Igneous rock associations in Canada 3. Large Igneous Provinces (LIPs) in Canada and adjacent regions: 3 Ga to Present.SUMMARY
Earth history is punctuated by numerous periods during which large volumes of mafic maf·ic
Containing or relating to a group of dark-colored minerals, composed chiefly of magnesium and iron, that occur in igneous rocks. magma were emplaced. Such magmas not generated by a 'normal' spreading ridge or by subduction sub·duc·tion
A geologic process in which one edge of one crustal plate is forced below the edge of another.
[French, from Latin subductus, past participle of are termed Large Igneous Provinces Large Igneous provinces (LIPS) were originally defined by Coffin and Eldholm (1992) as areas of Earth's surface that contain very large volumes of magmatic rocks (typically basalt but including rhyolites) erupted over extremely short geological time intervals of a few million years (LIPs), and consist of continental flood basalts A flood basalt or trapp basalt is the result of a giant volcanic eruption or series of eruptions that coats large stretches of land or the ocean floor with basalt lava. Flood basalts have occurred on continental scales (large igneous provinces) in prehistory, creating great , volcanic rifted margins, oceanic plateaus oceanic plateau
or submarine plateau
Large submarine elevation rising sharply at least 660 ft (200 m) above the surrounding seafloor and having an extensive, relatively flat or gently tilted summit. , ocean basin flood basalts, submarine ridges, and seamount seamount
Large submarine volcanic mountain rising at least 3,000 ft (1,000 m) above the surrounding seafloor; smaller submarine volcanoes are called sea knolls, and flat-topped seamounts are called guyots. Seamounts are abundant and occur in all major ocean basins. chains. Associated felsic rocks felsic rock
Igneous rock dominated by the light-coloured, silicon- and aluminum-rich minerals feldspar and quartz. The presence of these minerals gives felsic rock its characteristic light gray colour. may also be present. LIPs of Mesozoic and Cenozoic age are typically the best preserved. Those of Paleozoic and Proterozoic age are usually more deeply eroded e·rode
v. e·rod·ed, e·rod·ing, e·rodes
1. To wear (something) away by or as if by abrasion: Waves eroded the shore.
2. To eat into; corrode. , and consist of flood basalt remnants and a deep-level plumbing system (of giant dyke swarms, sill provinces and layered intrusions). In the Archean the most promising LIP candidates are greenstone belts Greenstone belts are zones of variably metamorphosed mafic to ultramafic volcanic sequences with associated sedimentary rocks that occur within Archaean and Proterozoic cratons between granite and gneiss bodies. containing komatiites. Many LIPs have been linked to regional-scale uplift, continental rifting continental rift
A long, narrow fissure in the Earth marking a zone of the lithosphere that has become thinner due to extensional forces associated with plate tectonics. and breakup breakup
The division of a company into separate parts. The most famous breakup to date was the 1984 division of AT&T (formerly, American Telephone & Telegraph Company). This breakup was intended to increase competition in the communications industry. , and climatic crises. They can be used as precisely dated time markers in the stratigraphic stra·tig·ra·phy
The study of rock strata, especially the distribution, deposition, and age of sedimentary rocks.
strat record, and are key targets for Ni-Cu-PGE exploration. LIPs have also become a focus in the debate on the existence and nature of mantle plumes.
Canada has a rich record of LIPs. At least 80 candidates are recognized in Canada and adjacent regions, with ages ranging from 3100 to 17 Ma. We review proposed links between the LIP record of Canada and mantle plumes, continental breakup, regional uplift, and ore deposits. However, given that many mafic units in Canada remain poorly characterized, a concerted geochronology geochronology
Dating and interpretation of geologic events in the history of the Earth. The classical technique of geochronology was stratigraphy, including faunal succession. campaign with integrated paleomagnetism paleomagnetism, study of the intensity and orientation of the earth's magnetic field as preserved in the magnetic orientation of certain minerals found in rocks formed throughout geologic time. and geochemistry geochemistry, study of the chemical changes on the earth. More specifically, it is the study of the absolute and relative abundances of chemical elements in the minerals, soils, ores, rocks, water, and atmosphere of the earth and the distribution and movement of would be invaluable in expanding the application of the Canadian LIP record to solving major geological problems.
L'histoire de la Terre est La Terre (The Earth) is a novel by Émile Zola, published in 1887. It is the fifteenth novel in Zola's Rougon-Macquart series. The action takes place in a rural community in La Beauce, an area of northern France. ponctuee de nombreuses periodes de mise en place Mise en place (IPA pronunciation: [miz eñ 'plass]), literally translated from French, means "setting in place." Culinary Institute of America describes the term as "Everything in place". de forts volumes de magma mafiques. De tels magmas qui ne sont pas issus de zones d'expansion << normale >> ou de subduction sont appeles Grandes provinces ignees (GPI (Graphical Programming Interface) A graphics language in OS/2 Presentation Manager. It is a derivative of the GDDM mainframe interface and includes Bezier curves. ), et celles-ci sont constituees de basaltes d'epanchements continentaux, de marges de fosse volcaniques, de plateaux oceaniques, d'epanchements de basaltes de bassins oceaniques, de cretes sous-marines, et de chaines de monts sous-marines. Peuvent egalement y etre associees des suites de roches felsiques. Generalement, les GPI du Mesozoique et du Cenozoique sont les mieux preservees. Celles du Proterozoique et du Paleozoique sont generalement plus fortement erodees et sont constituees de vestiges de basaltes d'epanchement et des reseaux de conduits d'origine (reseaux geants de dykes, provinces de filons-couches et d'intrusifs stratifiees). Dans l'Archeen, les meilleurs candidats sont representes par les bandes de roches vertes a komatiites. De nombreuses GPI ont ete associees a des episodes de soulevement regionaux, de derives ou de fragmentations continentales, ainsi qu a des crises climatiques. Elles peuvent servir de marqueurs temporels stratigraphiques et sont des cibles de premiere importance dans l'exploration de gisements de Cu-Ni-EGP. Les GPI sont aussi devenues des arguments tres consideres dans le debat sur l'existence et la nature des panaches mantelliques.
Le Canada possede de riches archives de GPI, et au moins 80 candidatures ont ete isolees sur le territoire canadien et dans les regions adjacentes, leur age delimitant une fourchette fourchette /four·chette/ (fldbomacr-shet´) [Fr.] frenulum of pudendal labia.
See frenulum of pudendal lips. allant de 3 100 Ma a 17 Ma. Nous passons en revue revue, a stage presentation that originated in the early 19th cent. as a light, satirical commentary on current events. It was rapidly developed, particularly in England and the United States, into an amorphous musical entertainment, retaining a small amount of les liens proposes entre la suite des GDI (Graphics Device Interface) The traditional programming interface (API) for output in Windows. When an application needs to display or print, it makes a call to a GDI function and sends it the parameters for the object that must be created. canadiennes d'une part, et celle Celle (tsĕl`ə), city (1994 pop. 73,670), Lower Saxony, N Germany, on the Aller River. Its manufactures include food products, electronic components, chemicals, and textiles. Wax processing and horse breeding are important locally. des panaches mantelliques, des fragmentations continentales, des soulevements regionaux, et des gisements mineraux, d'autre part. Toutefois, vu le pietre etat de caracterisation des unites mafiques au Canada, une campagne de caracterisation geochronologique, paleomagnetique et geochimique serait d'une valeur inestimable in·es·ti·ma·ble
1. Impossible to estimate or compute: inestimable damage. See Synonyms at incalculable.
2. pour favoriser l'utilisation des GDI canadiennes pour nous aider a solutionner de grands problemes geologiques.
Large Igneous Provinces (LIPs) represent voluminous magmatic events that were not generated by a 'normal' spreading ridge or by subduction (Coffin and Eldholm, 1994; 2001; Ernst et al., 2004). They may be emplaced as often as once every 10 Ma (e.g. Coffin and Eldholm, 2001), and time series analysis of the LIP record for the past 3.5 Ga suggests weak cyclicity (Isley and Abbott, 2002; Prokoph et al., 2004).
The most dramatic LIPs are emplaced rapidly (within <10 Ma and often within only a few Ma). These include continental flood basalts, seaward-dipping reflector reflector: see telescope. sequences, oceanic plateaus, and ocean basin flood basalts. Continental flood basalts can be as large as several million cubic km (e.g. the Siberian Traps The Siberian Traps (Russian: Сибирские траппы) form a large igneous province in Siberia. ; Reichow et al., 2002). The largest LIP is the Ontong Java oceanic plateau, which has a volume of 44.4 million cubic km (Coffin and Eldholm, 2001) for combined extrusive ex·tru·sive
1. Tending to push or thrust out.
2. Tending to protrude or project.
3. Derived from magma poured out or ejected at the earth's surface. Used of igneous rocks.
Adj. 1. (6 million cubic km) and intrusive components (Courtillot and Renne, 2003). The initial large-volume short-duration stage of magmatism of some LIPs has been linked to the arrival of a mantle plume (e.g. White and McKenzie, 1989; Campbell and Griffiths, 1990; Coffin and Eldholm, 1994; 2001; Campbell, 1998, 2001; Ernst and Buchan, 2001; Courtillot et al., 2003). Subsequent rifting/breakup is often associated with a second burst of volcanism volcanism
Any of various processes and phenomena associated with the surface discharge of molten rock or hot water and steam, including volcanoes, geysers, and fumaroles. (Campbell, 1998) by decompression decompression /de·com·pres·sion/ (de?kom-presh´un) removal of pressure, especially from deep-sea divers and caisson workers to prevent bends, and from persons ascending to great heights. melting (White and McKenzie, 1989). In addition, LIP magmatism can continue for prolonged periods after the initial outburst (or outbursts), in the form of seamount chains and ridges, which are usually explained as hotspot tracks associated with a plume tail. Other models invoke plate fracturing and 'edge convection' (upper mantle convection Mantle convection is the slow creeping motion of Earth's rocky mantle in response to perpetual gravitationally unstable variations in its density. Material near the surface of Earth, particularly oceanic lithosphere, cools down by conduction of heat into the oceans and atmosphere, between thick and adjacent thin lithosphere lithosphere (lĭth`əsfēr '), brittle uppermost shell of the earth, broken into a number of tectonic plates. The lithosphere consists of the heavy oceanic and lighter continental crusts, and the uppermost portion of the mantle. ), and have been suggested as an alternative to plume models for LIPs and hotspot chains (e.g. Anderson, 2001; Foulger and Natland, 2003).
The volcanic portion of older continental LIPs is largely removed by erosion and deformed de·formed
Distorted in form. during continental collision
Any of a group of igneous and metamorphic rocks, rich in iron and magnesium, whose origin is associated with an early phase of the development of a geosyncline. complexes (e.g., Coffin and Eldholm, 2001; Moores, 2002).
The extrapolation (mathematics, algorithm) extrapolation - A mathematical procedure which estimates values of a function for certain desired inputs given values for known inputs.
If the desired input is outside the range of the known values this is called extrapolation, if it is inside then of the LIP record into the Archean is more speculative. There are erosional remnants of typical flood basalt provinces, namely the Fortescue sequence of the Pilbara craton The Pilbara craton (the Pilbara province in northwest Western Australia), along with the Kaapvaal craton (the Kaapvaal province of South Africa) are the only remaining areas of pristine Archaean 3.6-2.7 Ga crust on Earth. of Australia and the Ventersdorp sequence of the Kaapvaal craton The Kaapvaal craton (Limpopo province of South Africa), along with the Pilbara craton of Western Australia, are the only remaining areas of pristine 3.6-2.5 Ga crust on Earth. of southern Africa
See also: Volcanic occur as deformed and fault-fragmented packages termed greenstone belts. Among these, the best candidates for LIPs are thick tholeiite tholeiite
Any of a series of igneous rocks that are similar in composition to basalt, but are richer in silica and iron and poorer in aluminum than basalt is. Tholeiites form especially at mid-ocean ridges and in continental rift areas. sequences that contain komatiites. The nature of Archean LIPs is discussed in greater detail below.
LIPs are important 1) for testing plume and non-plume models for the generation of LIPs; 2) as precise time markers for stratigraphic correlations; 3) as an aid in reconstructing continents; and 4) as the hosts of major PGE PGE Pacific Gas and Electric Company
PGE Portland General Electric
PGE Prostaglandin E
PGE Platinum Group Elements
PGE Pacific Great Eastern (Railroad)
PGE Phenyl Glycidyl Ether
PGE Perfect Girl Evolution deposits and as a potential tool in diamond exploration. In addition, they can be helpful in studying 5) climatic effects, and 6) regional uplift. We return to these topics after a review of the LIP record of Canada and adjacent regions.
PRELIMINARY LIP HISTORY OF CANADA Canada is a country of 32 million inhabitants that occupies the northern portion of the North American continent, and is the world's second largest country in area. AND ADJACENT REGIONS
Our compilation is based on a recent summary of the global LIP distribution (Ernst and Buchan, 2001) and a newly published compilation of dyke swarms and related magmatic units in Canada and adjacent regions (Buchan and Ernst, 2004). We currently recognize at least 80 LIPs and possible LIP remnants in and adjacent to Canada. The Proterozoic and Phanerozoic mafic magmatic record is reviewed first since its links with LIPs are better defined (Table 1, Fig. 1). The more speculative Archean LIP history follows (Table 2, Fig. 1).
The Proterozoic record relies heavily on diabase diabase: see basalt.
Fine- to medium-grained, dark gray to black intrusive igneous rock. Diabase is one of the dark rocks known commercially as “black granite. dyke swarms and sills Sills , Beverly Originally Belle Silverman. Born 1929.
American operatic soprano and manager who joined the New York City Opera in 1953 and was its general director from 1980 to 1989.
Noun 1. (Fig. 2). Dykes injected laterally into the interior of continents have a preservation potential that is much greater than that of associated lavas, and therefore provide a robust record of cratonic LIP events (e.g. Halls, 1982; Fahrig, 1987; Buchan and Halls, 1990).
The compilation includes information on tectonic tectonic /tec·ton·ic/ (tek-ton´ik) pertaining to construction. setting. Our criteria for determining setting rely heavily on dyke swarm geometry and its relationship to cratonic margins (Fig. 3, Table 3). Events are inferred to have a mantle plume origin if a giant radiating ra·di·ate
v. ra·di·at·ed, ra·di·at·ing, ra·di·ates
1. To send out rays or waves.
2. To issue or emerge in rays or waves: Heat radiated from the stove. dyke swarm is present. Giant linear dyke swarms that extend into a craton craton (krā`tŏn): see continent. (i.e. trend perpendicular to a cratonic margin) are inferred to represent an aulacogen-type swarm ('failed-arm' type in Fahrig, 1987), and can also be used to infer a plume origin with the plume centre situated at the edge of a craton. By contrast, linear swarms that parallel the edge of a craton may simply be rift/breakup related (Ernst and Buchan, 1997) or may possibly represent a back arc rifting setting (e.g. Rivers and Corrigan, 2000), or overriding of a spreading ridge (Gower and Krogh, 2002).
In addition (Table 3), those Archean greenstone belts containing komatiites are inferred to be plume-related on the basis of the elevated temperatures required for generation of komatiites (e.g. Campbell, 1998, 2001; Arndt et al., 1998; Condie, 2001). Finally, small, intraplate events not obviously linked to a cratonic boundary are categorized cat·e·go·rize
tr.v. cat·e·go·rized, cat·e·go·riz·ing, cat·e·go·riz·es
To put into a category or categories; classify.
cat as 'hotspots'.
Below (and in Tables 1 and 2) we summarize the main events, their age distribution and tectonic setting. It should be noted that referencing has been minimized in the text below because detailed referencing is available through Tables 1 and 2. Also note that we have included number-labels of the form [#14a] in order to facilitate easy cross-correlation with entries in Tables 1 and 2, and with the distribution of main units in Figure 1.
Proterozoic to Present
2.51-2.41 Ga: The earliest Proterozoic LIPs consist of dykes, layered intrusions and volcanic rocks and are mainly associated with the eastern and southern margin of Laurentia. Most notable are the ca. 2.5 Ga Mistassini [#1a] and 2.49-2.45 Ga Matachewan events [#1b] whose radiating diabase dyke swarms locate two plume centres about 800 km apart, and imply rifting of the southeast margin of Laurentia at this time. The conjugate conjugate /con·ju·gate/ (kon´jdbobr-gat)
1. paired, or equally coupled; working in unison.
2. a conjugate diameter of the pelvic inlet; used alone usually to denote the true conjugate diameter; see margin may have been Baltica, which has a remarkably similar age range of magmatism (e.g. Heaman, 1997; Buchan et al., 2000), or the Hearne craton (Bleeker, 2004). Additional units in eastern and southwestern Laurentia, the 2.505 Ga Ptarmigan ptarmigan (tär`məgən): see grouse.
Any of three or four species of grouse (genus Lagopus) of cold regions. Ptarmigan plumage changes from white in winter to gray or brown, with barring, in spring and summer. dykes [#1a, unit not displayed in Fig. 1] and the 2.408 Ga Du Chef dykes [#1a, unit not displayed in Fig. 1] have uncertain relationship with the events in the southeastern and southern parts of the Superior Province.
[FIGURE 1 OMITTED]
Elsewhere in Canada, there are additional events falling in this age range. These include the Kaminak dykes [#1c] in the Hearne Province, and the Mirond Lake dykes [#1d] in the Sask craron of the Trans Hudson orogen.
2.24-2.21 Ga: The next burst of activity in Laurentia was widespread in the North Atlantic (Nain), Superior, and Slave cratons The Slave craton is a relatively small Archean craton (about 300,000 km²) located in the Northwest Territories of Canada. It is dominated by ca. 2.73-2.63 Ga greenstones and turbidite sequences and ca. 2.72-2. [#2a-d]. The 2.235 Ga Kikkertavak swarm [#2a] has been linked with breakup along the southern margin of the North Atlantic Craton (lower Aillik Group) at 2.178 Ga (Ketchum et al., 2001) although the long interval between emplacement of the swarm and breakup 57 Ma later is problematic. The 2.21 Ga BN1 (and possibly correlative Having a reciprocal relationship in that the existence of one relationship normally implies the existence of the other.
Mother and child, and duty and claim, are correlative terms. MD1) dykes [#2b] of western Greenland are also likely linked with North Atlantic Craron breakup.
Superior Province elements of this age include the 2.217-2.210 Ga Ungava giant radiating swarm [#2c] that spans the entire eastern half of the Superior Province (Buchan et al. 1998). The convergence point marks a plume centre and possible breakup of a continental fragment from the eastern margin of the Superior Province. Buchan et al. (1998) proposed that the Nipissing sills [#2c] of the Southern Province were fed laterally via the Ungava radiating swarm from the plume centre region >1000 km to the northeast.
The Slave Province is another node of activity in this age interval. The 2.23 Ga Malley and 2.21 Ga MacKay dyke swarms [#2d] are both roughly linear, and crosscut at a shallow angle. If they represent rift-parallel swarms (Fig. 3c) then they could be linked to breakup along the southeastern margin of the Slave Province (LeCheminant et al., 1996). However, if they represent an aulacogen (Failed-arm) type swarm (Fig. 3b), then the plume centre and locus of breakup would have to lie at one end of the swarms; i.e., either on the east or southwest margins of the Slave Province.
[FIGURE 3 OMITTED]
2.19-2.17 Ga: Widespread activity occurred during this age interval. The oldest activity is represented by the 2.19 Ga Dogrib dyke swarm [#3a] in the Slave Province and the similar age Tulematu-MacQuoid swarm [#3b] in the Hearne Province. While a connection would seem likely based on the age match, preliminary paleomagnetic data indicate that the Slave and Rae cratons The Rae craton is an Archean craton located in northern Canada north of the Superior craton. Ungava Peninsula
The Ungava Peninsula, situated on the northeast portion of the Canadian Shield, is where the Rae Province connects with the Superior Province. were not in their present relative positions at this time (LeCheminant et at., 1997). Globally, a stage of Birimian magmatic activity in Western Africa has this age (event #187 in Ernst and Buchan, 2001). Magmatic activity in the Slave Craton continues to 2.18 Ga, the age of the Duck Lake Duck Lake, small lake, central Sask., Canada, SW of Prince Albert. It was the scene of the first encounter in Riel's Rebellion (see under Riel, Louis) in 1885. sill [#3a, unit not displayed in Fig. 1].
The 2.17 Ga Biscotasing dyke swarm [#3c] is one of the most widespread in Canada, extending throughout much of the southern and central Superior Craton The Superior craton (or Superior Province) forms the core of both the North American continent and the Canadian Shield. It extends from Quebec in the east to eastern Manitoba in the west. . Similar age activity [#3d] is present as the Payne River dykes in northern Ungava (Cape Smith Belt) and Cramolet Lake sills (part of "Cycle 1" magmatism) in the Labrador Trough. It seems unlikely that all these elements are part of a single event, but the association of Payne River dykes and "Cycle 1" magmatism in the Labrador Trough suggests a link to breakup along the eastern Superior Province. Globally, an identical age has also been obtained fiom a quartz diorite Quartz diorite is an igneous, plutonic (intrusive) rock, of felsic composition, with phaneritic texture. Feldspar is present as plagioclase (typically oligoclase or andesine) with 10% or less potassium feldspar. Quartz is present at between 5 to 20% of the rock. dyke in the Wyoming Province, although paleomagnetic data are inconclusive INCONCLUSIVE. What does not put an end to a thing. Inconclusive presumptions are those which may be overcome by opposing proof; for example, the law presumes that he who possesses personal property is the owner of it, but evidence is allowed to contradict this presumption, and show who is regarding the relative locations of the Wyoming and Superior provinces at this time (Harlan et al., 2003a).
2.12-2.07 Ga: In the Superior Province there are several distinct stages of activity during this time interval. The 2.12-2.10 Ga Marathon dyke swarm [#4a] is a broadly linear swarm that cuts northward north·ward
adv. & adj.
Toward, to, or in the north.
A northern direction, point, or region.
north across the Superior Province from Lake Superior. This is an aulacogen-type swarm, and therefore could be associated with a breakup margin at the end of the swarm. Since the swarm may reach the cratonic margin on its north end as well as its south end (c.f. Fig. 3b), then the applicable breakup margin may also be at either end, either to the north in Hudson Bay Hudson Bay, inland sea of North America, c.475,000 sq mi (1,230,000 sq km), c.850 mi (1,370 km) long and c.650 mi (1,050 km) wide, E central Canada. Hudson Bay and James Bay (its southern extension) and all their islands border Nunavut Territory, Manitoba, Ontario, or to the south in Lake Superior.
Slightly younger is the 2.09-2.07 Ga Cauchon swarm [#4b], which has been linked with breakup along the northwest margin of the Superior Province (e.g. Halls and Heaman, 2000). Two other events are also of this age: the 2.077 Ga Fort Frances Fort Frances, town (1991 pop. 8,891), SW Ont., Canada, on Rainy River, opposite International Falls, Minn. It is chiefly a lumbering center with sawmills and a pulp and paper factory. Tourism is also an important industry, with abundant fishing and hunting nearby. (Kenora-Kabetogama) dykes [#4c] that are linked with breakup along the southern margin of the Superior Province, and the 2.069 Ga Lac Esprit swarm [#4d] located east of James Bay James Bay, shallow southern arm of Hudson Bay, c.300 mi (480 km) long and 140 mi (230 km) wide, E central Canada, in Nunavut Territory between Ont. and Que. Numerous rivers flow into the bay; many of these have been developed for hydroelectric power in Quebec (see . There are no obvious connections between these widely separated but coeval co·e·val
Originating or existing during the same period; lasting through the same era.
One of the same era or period; a contemporary. 2.07 Ga events. However, future identification of additional dykes of this age in intervening areas could suggest a link.
In the Hearne Province, the widespread 2.111 Ga Griffin gabbros (formerly Hurwitz gabbros) [#4e] are presumably pre·sum·a·ble
That can be presumed or taken for granted; reasonable as a supposition: presumable causes of the disaster. linked to breakup along the Trans-Hudson margin (Aspler el al., 2002).
Finally, the Napaktok swarm [#4f] trends perpendicular to and extends along the Labrador coast for at least 200 km. These dykes have an uncertain age between 2.50 and 2.10 Ga, and uncertain tectonic setting. Although more than one age of dykes may be present, at least part of this activity is dated by the 2.121 Ga age for the Tikkigatsiagak dyke.
2.05-2.02 Ga: In the Nain Province, the 2.045 Ga Iglusuataliksuak dyke [#5a, unit not displayed in Fig. 1] is coeval with the Kangfimuit swarm [#5a] of adjacent southern Greenland. The combined 2.04-2.05 Ga event would be areally significant, and may represent a breakup event associated with the northern margin of the North Atlantic Craton. Korak sills associated with the lower Povungnituk sequence [#5b] in the Cape Smith Belt of the northeastern Superior Province are of the same age as the Iglusuataliksuak dyke. However, given that the North Atlantic Craton had not yet docked at this time, two independent events are probable. The younger Upper Povungnituk sequence [#6c] is discussed below in the next section.
The third locus of activity of this age is in the Slave Craton. The 2.038 Ga Hearne dykes [#5c] parallel the southern Slave margin, possibly representing breakup along that margin (cf. with evidence discussed above for an earlier 2.23-2.21 Ga breakup along that margin associated with the Malley/ MacKay swarms [#2d]). In contrast, the younger 2.030-2.023 Ga Lac de Gras Lac de Gras is a lake approximately 300 km north of Yellowknife, Northwest Territories, Canada. Lac de Gras was the centre of the Canadian diamond rush of the 1990s. There are two working diamond mines in the area, Ekati Diamond Mine, and Diavik Diamond Mine. swarm [#5d] is not easily linked to any margin. It is centred in the Slave province and slightly converges to the north toward the similar-aged Booth River Complex in the Kilohigok sedimentary basin The term sedimentary basin is used to refer to any geographical feature exhibiting subsidence and consequent infilling by sedimentation. As the sediments are buried, they are subjected to increasing pressure and begin the process of lithification. . LeCheminant et at. (1996) suggest that the Lac de Gras swarm is coeval with rifting on the western margin of the Slave Province.
2.00-1.95 Ga: Magmatism of this age range is distributed along the circum-Superior margin (e.g. Baragar and Scoates 1987).
In the Belcher Islands Belcher Islands, c.1,110 sq mi (2,870 sq km), in E Hudson Bay, Nunavut Territory, Canada, off W Quebec. Flaherty Island is the largest of the tundra-covered group. there are two main volcanic suites, the Eskimo [#6a] and overlying overlying
suffocation of piglets by the sow. The piglets may be weak from illness or malnutrition, the sow may be clumsy or ill, the pen may be inadequate in size or poorly designed so that piglets cannot escape. Flaherty [#6b] volcanics. Based on paleomagnetic correlations, the Eskimo volcanics may be linked with Richmond Gulf, Persillon, Pachi and Nastapoka Group volcanics (Chandler and Schwarz, 1980; Schwarz and Fujiwara, 1981), and with 1.998 Ga Minto dykes (Buchan et at., 1998). The Minto dykes and correlated suites are also coeval and perhaps cogenetic with the precisely dated Watts Group ophiolitc. The Eskimo volcanics have been linked geochemically with the western Povungnituk [#6c] (Legault et al., 1994), but this link is now doubtful based on more extensive recent geochemical study (Modeland et al., 2003).
The overlying Flaherty Group [#6b] is essentially undated un·dat·ed
1. Not marked with or showing a date: an undated letter; an undated portrait.
2. except for a very uncertain Pb-Pb age of 1960+/-80 Ma. However, paleomagnctic data suggest a link with the Haig and Sutton Inlier in·li·er
An area or formation of older rocks completely surrounded by younger layers.
[in1 + (out)lier.] sills (Schwarz and Fujiwara, 1981). Geochemical correlations indicate that the Flaherty Group may be linked with the upper (eastern) Povungnituk [#6c] (Legault et al., 1994).
The Cape Smith Belt includes the tectonically juxtaposed jux·ta·pose
tr.v. jux·ta·posed, jux·ta·pos·ing, jux·ta·pos·es
To place side by side, especially for comparison or contrast. 1.998 Ga Watts Group, 2.04-1.96 Ga Povungnituk suites [#5b & #6c], and ca. 1.87 Ga Chukotat Group volcanics [#8b]. (Note that the older 2.04 Ga portion of the Povungituk sequence [#5b] was discussed in the previous section.)
Additional magmatism in this age interval is present in the Nain Province. A 1.95 Ga plateau basalt basalt (bəsôlt`, băs`ôlt), fine-grained rock of volcanic origin, dark gray, dark green, brown, reddish, or black in color. Basalt is an igneous rock, i.e., one that has congealed from a molten state. sequence in the Mugford Mountains of Labrador [#6d] represents a rifting event (Wardle et al., 2002) that may be more widespread in the North Atlantic Craton based on possible correlations with the Ramah and Snyder groups.
1.90-1.88 Ga (Tram Hudson Orogen and Rae-Hearne Craton): Several non-arc packages are associated with the Trans Hudson during this age interval. These include the Sandy Bay Sandy Bay can refer to:
Three-dimensional construction made from household materials such as rope and newspapers or from any found materials. of the Flin Flon Flin Flon (flĭn flŏn), city (1991 pop. in Manitoba, 7,119; in Saskatchewan, 330), on the Man.-Sask. border, Canada. It is a mining and smelting center in a region producing copper, zinc, silver, gold, and cadmium; it also serves a lumbering Belt [#7a], which contains accreted oceanic crust oceanic crust
See under crust. of various affinities, including an oceanic plateau. In addition there are the Josland and related sills [#7b] in the Lynn Lake Belt of the Amisk collage collage (kəläzh`, kō–) [Fr.,=pasting], technique in art consisting of cutting and pasting natural or manufactured materials to a painted or unpainted surface—hence, a work of art in this medium. , and the mafic magmatism in the Piling-Penhryn [#7c], and Lake Harbour [#7d] groups on Baffin Island Baffin Island, 183,810 sq mi (476,068 sq km), c.1,000 mi (1,610 km) long and from 130 to 450 mi (210–720 km) wide, in the Arctic Ocean, Nunavut Territory, Canada. It is the fifth largest island in the world and the easternmost member of the Arctic Archipelago. .
1.88-1.86 Ga (Circum-Superior Province): 1.88-1.87 Ga mafic magmatism surrounds the Superior Province on all sides except the southeast where, if originally present, it has been obscured by the Grenville allochthon. This magmatism is present in the Labrador Trough (Montagnais sills belonging to New Quebec Orogen Cycle 2 [#8a]), Cape Smith Belt (Chukotat Group [#8b]), northwest Superior province (Fox River sill, Molson dykes, Thompson Nickel Belt
Nickel Belt is an informal nickname for the Sudbury region in Northern Ontario, because of the belt of nickel ore deposits found in the area. , and Wmnipegosis komatiites [#8c]), and the Animikie Basin and Marquette Range Supergroup of the southern Province (Hemlock hemlock, any tree of the genus Tsuga, coniferous evergreens of the family Pinaceae (pine family) native to North America and Asia. The common hemlock of E North America is T. and Gunflint gun·flint
The piece of flint used to strike the igniting spark in a flintlock.
Noun 1. gunflint - the piece of flint that provides the igniting spark in a flintlock weapon formations and associated Kiernan sills [#8d]). The 1.88 Ga event or events are of particular importance because they represent a metallotect; the major NiCu-PGE sulphide sulphide: see sulfide. ores of both the Thompson Nickel Belt and the Raglan deposits of the Cape Smith Belt appear to be associated with this age of magmatism (e.g. Hulbert et al., 2004 for TNB TNB Tenaga Nasional Berhad (electric power utility in Malaysia)
TNB Tacoma Narrows Bridge
TNB Thomas and Betts
TNB Télévision Nationale du Burkina (Burkina Faso) ; Wodicka, pers. comm. 2004 for Raglan).
1.88 Ga magmatism in the Cape Smith belt and Labrador Trough has been linked to rifting and possible separation of a microcontinent (St-Onge et al., 2000). However, the magmatism in both the Thompson belt and Animikie basin occurs within a broad period of ocean closure, and therefore may represent back-arc rifting. The recent discovery of a major ca. 1.88 Ga dyke, the NW-trending Pickle pickle, general term for fruits or vegetables preserved in vinegar or brine, usually with spices or sugar or both. Vegetables commonly pickled include the beet, cabbage, cauliflower, cucumber, olive, onion, pepper, and tomato. Crow dyke [#8c] crossing the interior of western Superior Province provides a link between the Animikie Basin and Thompson Belt magmatic activity, and may suggest a mantle plume model for the western part of the 1.88 Ga event (Buchan et al., 2003).
1.83-1.82 Ga: The Sparrow dyke swarm [#9a] of the western Rae Province is as yet uncorrelated with any volcanic sequences. Other units of similar age but uncertain relationship are 1) a meta-gabbro and two monzogabbros with U-Pb ages of 1.83-1.82 Ga in the Close Lake, Wollaston-Mudjatik Transition zone [#9a, unit not displayed in Fig. 1], and 2) the widespread Christopher Island formation volcanics of the Baker Basin region [#9a, unit not displayed in Fig. 1].
1.75-1.71 Ga: The Cleaver dykes in the Great Bear Magmatic Zone, the Hadley Bay sills on Victoria Island and MacRae Lake dykes in the northern Rae Province are coeval in age [#10a], suggesting a widespread event in northwestern Canada. This large region of 1.75 Ga activity could be associated with the generation of Wernecke sediments in the northwestern Cordillera cor·dil·le·ra
An extensive chain of mountains or mountain ranges, especially the principal mountain system of a continent.
[Spanish, from cordilla, diminutive of cuerda, cord , and the approximately 40 Ma younger 1.71 Ga Bonnet Plume River The Bonnet Plume River is one of the Yukon's better-known rivers. It flows from a mountain lake source in the Bonnet Plume Range in the Mackenzie Mountains through several mountain ranges to its confluence with the Peel. marie magmatism [#10a; unit not displayed in Fig. 1]. The Wernecke sediments are inferred to represent the earliest rift stage of activity associated with the Cordilleran margin (Cook et al. in Percival et al., 2004). The Pitz formation fclsic volcanics and Nueltin felsic fel·sic
Containing a group of light-colored silicate minerals that occur in igneous rocks.
[fel(dspar) + s(ilica) + -ic. intrusive suite [#10a, units not displayed in Fig. 1] of the Baker Basin region are similar in age.
Subhorizontal seismic reflectors interpreted as sills are present over a huge region (about 120,000 sq. km) in the basement underlying the Western Canada
Western Canada, commonly referred to as the West Basin. These Winagami sills [#10b] are roughly bracketed in age between 1.89 and 1.76 Ga, and have been tentatively linked with the Cleaver dykes by Ross and Eaton (1997).
1.64 Ga: The 1000 km long Melville Bugt swarm [#11a] is located in western Greenland. Although close to Baffin Island and other Canadian Arctic islands Arctic Islands may mean:
1.47-1.44 Ga: There are two nodes of activity with this age. The Belt Basin of the western Cordillera contains extensive Moyie-Purcell sills and associated Purcell volcanics [#12a]. These may have been generated when a continent (perhaps Australia) was rifted from the western margin of Laurentia. It is also interesting that in the Wyoming Province there is an extensive linear dyke swarm (Tobacco Root--Group B; [#12a]) of the same age. Assuming that the dykes fed the volcanics and sills, we can infer that the magma source area was either on the western margin of Laurcntia in the vicinity of the Belt Basin, or far to the southeast on the southern margin of Laurentia with magma being transported laterally via the dykes to the Belt Basin. Long distance feeding of a sill province has been described above for the 2.22 Ga Ungava event, and may be a not uncommon consequence of the lateral flow pattern in giant dyke swarms (e.g. Ernst and Buchan, 1997).
A second node of this age is located in southeastern Laurentia. The Michael and Shabagamo gabbros [#12b] have an approximate age of 1.47-1.46 Ga and represent a significant event in the southeastern Laurentia. They are located in a back-arc setting to the evolving Grenville Orogen (Rivers et al. in Percival et al., 2004).
1.38 Ga: Hart River volcanic rocks and sills, and coeval sills from the Belt Basin region [#13a], may represent rift sequences (Abbott, 1997; Thorkelson et al., 2003).
1.28-1.27 Ga: One of the largest magmatic events in Canada occurred at 1.267 Ga [#14a]. Most prominently this event consists of the Mackenzie giant radiating dyke swarm. Mackenzie dykes (Fig. 2a) fan over an arc of 100[degrees] and cover almost 3 million sq. km of the Canadian Shield Canadian Shield or Laurentian Plateau (lôrĕn`chən), U-shaped region of ancient rock, the nucleus of North America, stretching N from the Great Lakes to the Arctic Ocean. . Coeval Coppermine volcanics and the Muskox musk·ox or musk ox
n. pl. musk·ox·en
A large, stocky, oxlike bovid (Ovibos moschatus) native to the coastal regions of northern Canada and Greenland, having broad flat horns with curved tips and a long, shaggy, brown or Intrusion are situated near the plume center, but additional volcanic and sill packages are distributed throughout the swarm and are inferred to be fed via lateral flow along dykes originating from near the plume center (e.g. Ernst and Baragar, 1992; Baragar et al., 1996). This LIP is presumed to be linked with continental breakup and formation of a northern ocean, which has been termed the Poseidon Ocean (G. Jackson cited in Fahrig, 1987). However, the missing rift block(s) has not yet been identified, although Siberia has been a repeated suggestion (see summary in Ernst et al., 2000; cf. Sears et al., 2004).
The North Atlantic Craton of North America North America, third largest continent (1990 est. pop. 365,000,000), c.9,400,000 sq mi (24,346,000 sq km), the northern of the two continents of the Western Hemisphere. and Greenland is another locus of magmatic activity during this time period [#14b]. The 1.280-1.277 Ga Nain-LP dykes of Labrador are correlative with the BD0 dykes of Greenland (Buchan et al., 1996). Also the 1.273 Ga Harp harp, stringed musical instrument of ancient origin, the strings of which are plucked with the fingers. Harps were found in paintings from the 13th cent. B.C. at Thebes. In different forms it was played by peoples of nearly all lands throughout the ages. dykes of Labrador may be linked with Gardar (BD1, BD2, BD3) dykes of Greenland (Baragar, 1977). The setting of this 1.28-1.27 Ga activity is unknown, but it is clearly distinct in location, dyketrend, and probably in origin from the coeval Mackenzie event. Also widespread in Labrador are the anorthosites, granites, diorites and troctolites of the older and probably unrelated 1.35-1.29 Ga Nain plutonic plu·ton·ic
Of deep igneous or magmatic origin: plutonic rocks.
[From Latin Pl suite (Ryan and James, 2004 and references therein).
Coeval activity of this age is represented globally by the Central Scandinavian Dolerite dol·er·ite
n. Chiefly British
A dark, fine-grained igneous rock; diabase.
[French dolérite, from Greek doleros, deceitful (from its easily being mistaken for diorite) Complex (sills) of the Baltic Shield Baltic Shield, the continental core of Europe, composed of Precambrian crystalline rock, the oldest of Europe. The tectonically stable region was not affected by the Caledonian, Hercynian, and Alpine mountain-building periods of Europe, although mountains did rise . Paleomagnetic data and geological evidence suggest a reconstructed location east of Greenland (Buchan et al., 2000, and references therein), which is supported by geological evidence (Bingen et al., 2002). Given its great spatial separation from Canada in this reconstruction, the Central Scandiuavian Dolerite Complex of Baltica must represent a separate event from the coeval Mackenzie (and also possibly the Nain Province) activity. The occurrence of multiple independent LIPs has been considered evidence for plume cluster events (Ernst and Buchan, 2002).
1.25-1.22 Ga: The Grenville Province and adjacent Superior Province contain widely separated packages of similar-aged magmatism. From southwest to northeast, these include 1.235 Ga Sudbury dykes [#15a], 1.25-1.225 Ga Seal Lake volcanic rocks and Naskaupi sills [#15b], and the 1.250 Ga Mealy meal·y
adj. meal·i·er, meal·i·est
1. Resembling meal in texture or consistency; granular: mealy potatoes.
a. Made of or containing meal.
b. dykes [#15b]. These 1.25-1.22 Ga events along the Grenville Orogen have not been previously linked to each other and more work is required to assess whether they represent disparate elements of the same event. They are situated in a back-arc setting with respect to the evolving Grenville orogen (e.g. Rivers and Corrigan, 2000; Rivers et al. in Percival et al., 2004). However a plume origin should not be ruled out. The Seal Lake suite has previously been considered analogous to a flood basalt sequence ("plateau basalt" is the term used in Baragar, 1977), and the aulacogen type geometry of the Sudbury dykes suggests derivation derivation, in grammar: see inflection. from a spreading center located to the southeast of the swarm (Fahrig, 1987).
1.18-1.14 Ga: Widely separated but possibly linked nodes of mafic magmatism of 1.18 Ga are distributed along the Grenville Orogen. Specifically, toward the northeast end of the Grenville Province the Davy Group sills and dykes [#16a] in the Wakeham Group have an age of 1.177 Ga. Similar ages are found in coronitic gabbros [#16a] in the Baie du Nord segment of Tshenukutish domain. Finally, the same age but with larger uncertainties applies to Algonquin metagabbros [#16a] in the Central Gneiss gneiss (nīs), coarse-grained, imperfectly foliated, or layered, metamorphic rock. Gneiss is characterized by alternating light and dark bands differing in mineral composition and having coarser grains than those of schist. Belt, southwestern Grenville Province.
Late Gardar magmatism in South Greenland ranges in age from 1.18-1.14 Ga [#16b], and includes the 1.18 and 1.163 Ga Giant Tugtutoq Dykes.
The sparsely distributed 1.141 Ga Abitibi dyke swarm [#16c] of the Central Superior Province has a width of 400 km and extends for nearly 700 km across the southern and eastern Superior Province. This event has long been considered as a precursor to the 1.109-1.085 Ga Keweenawan event [#17a] located at the southwest end of the swarm (next entry). However, the broadly linear pattern of the Abitibi swarm does not eliminate a possible source at the other (northeast end) of the swarm.
1.11-1.08 Ga: One of the most dramatic flood basalt events in Canada and the United States The United States and Canada share a unique legal relationship. U.S. law looks northward with a mixture of optimism and cooperation, viewing Canada as an integral part of U.S. economic and environmental policy. is arguably ar·gu·a·ble
1. Open to argument: an arguable question, still unresolved.
2. That can be argued plausibly; defensible in argument: three arguable points of law. the Keweenawan magmatism [#17a] of the Mid-Continent Rift (e.g. Ojakangas et al., 2001). It comprises at least 2 x [10.sup.6] cubic km of volcanic rocks and possibly an equal volume of intrusive rocks (Geol.) rocks which have been forced, while in a plastic or melted state, into the cavities or between the cracks or layers of other rocks. The term is sometimes used as equivalent to plutonic rocks ltname>. It is then contrasted with effusive or volcanic rocks.
See also: Intrusive (Fig. 2b). The Mid-Continent Rift (and subsurface sub·sur·face
Of, relating to, or situated in an area beneath a surface, especially the surface of the earth or of a body of water.
Adj. 1. lavas) can be traced eastward through Michigan and southwestward into the central United States The Central United States is sometimes conceived as between the Eastern United States and Western United States as part of a three-region model, roughly coincident with the Midwestern United States plus the western and central portions of the Southern United States; the term is . A similar age of activity is found in the "Southwestern USA Diabase Province", and in the Moores Lake sills of the Athabasca Basin The Athabasca Basin is a region of Northern Saskatchewan and Alberta Canada that is best known as the world's leading source of uranium. It currently supplies about 30% of the world's uranium.
The basin is located just to the south of Lake Athabasca. (1000 km to the northwest). The Keweenawan activity consists of main pulses of activity at 1.109-1.105 Ga and 1.100-1.094 Ca, but activity is continuous to 1.085 Ca. Emplacement of the Keweenawan LIP is similar in age to that of terminal collision of the Grenville orogen (Rivers et al. in Percival et al., 2004). Although a back-arc rifting origin linked to the coeval Grenville orogeny The Grenville orogeny was an episode of mountain-building (orogeny) associated with the assembly of the ancient supercontinent Rodinia. The Grenville orogeny occurred in the late Proterozoic eon, 1300-1000 million years ago (mya), as numerous continental plates collided around the has been suggested, the most widely accepted model links the event to a mantle plume on the basis of the great volume of tholeiitic magma generated in an intraplate setting (e.g. Ojakangas et al., 2001).
[FIGURE 2 OMITTED]
0.78 Ga: The Gunbarrel magmatte event [#18a] is distributed over a distance of 2400 km in western North America. Precise 0.780 Ga ages are found in the Hottah sheets of the Slave Province, the Mackenzie Mountains Mackenzie Mountains
A range of the northern Rocky Mountains in eastern Yukon Territory and western Northwest Territories, Canada, rising to 2,973.8 m (9,750 ft). dykes and sills, the MacDonald dykes, and the Tobacco Root- Group B and Wolf Creek Wolf Creek may refer to several places in the United States: Cities
0.72 Ga: Another major LIP event is represented by the Franklin dyke swarm [#19a] which extends throughout the southern Arctic Islands, but is most significant on Baffin Island, and also on reconstructed Greenland as the Thule swarm [#19a]. The convergence point marking the plume centre for this event is located north or northwest of Banks Island Banks Island, c.26,000 sq mi (67,340 sq km), NW Northwest Territories, Canada, in the Arctic Ocean, in the Arctic Archipelago. It is the westernmost of the group and is separated from the mainland by Amundsen Gulf. . Natkusiak volcanics, and Minto Inlier and Coronation sills [#19a] are also part of the Franklin event and are generally concentrated toward the plume centre region. The Franklin event may be linked with separation of an as yet unidentified continent.
Another possible locus of similar-aged activity is the Appalachians. A very approximate Rb-Sr age of 0.735 Ga has been suggested for coast-parallel dykes in basement inliers of the Appalachians of the United States United States, officially United States of America, republic (2005 est. pop. 295,734,000), 3,539,227 sq mi (9,166,598 sq km), North America. The United States is the world's third largest country in population and the fourth largest country in area. (event #72 in Ernst and Buchan, 2001). This activity can been linked with additional magmatism and a stage of rifting along the Laurentian margin in the southern Appalachians (Aleinikoff et al., 1995).
0.62-0.56 Ga (Laurentian margin, Appalachians): The formation of the Iapetus Ocean The Iapetus Ocean was an ocean that existed in the Southern Hemisphere between Laurentia (Scotland and North America) and Baltica (Scandinavia) between 400 and 600 million years ago. was preceded by several distinct major magmatic events along the eastern margin of Laurentia. These include the 0.615 Ga Long Range dykes [#20a], the 0.590 Ga Grenville-Adirondack fanning swarm [#20b] and the 0.563 Ga Sept lies layered intrusion [#20c]. The latter is roughly coeval with the Catoctin flood basalts [#20c, unit not displayed in Fig. 1] situated in the southern Appalachians of the United States. Other basaltic ba·salt
1. A hard, dense, dark volcanic rock composed chiefly of plagioclase, pyroxene, and olivine, and often having a glassy appearance.
2. A kind of hard unglazed pottery. units and syenitic sy·e·nite
An igneous rock composed primarily of alkali feldspar together with other minerals, such as hornblende.
[Latin Sy intrusions with ages 0.56 to 0.55 Ga are widely distributed Adj. 1. widely distributed - growing or occurring in many parts of the world; "a cosmopolitan herb"; "cosmopolitan in distribution"
bionomics, environmental science, ecology - the branch of biology concerned with the relations between organisms (Puffer puffer, common name for some tropical marine fish of the family Tetraodontidae. The puffers and their allies, the boxfish, the porcupinefish, and the ocean sunfish or headfish, form an odd group (order Tetraodontiformes). , 2002; Higgins and van Breemen, 1998).
[FIGURE 1 OMITTED]
The oldest event, the 0.615 Ga dykes [#20a] may have been linked to similar-aged magmatism in Baltica, which is represented by the aulacogen-type Egersund dykes (Bingen et al., 1998) and the coast-parallel Baltoscandian breakup swarm (event #55 in Ernst and Buchan, 2001). Two younger rifting events are also recorded in Laurentia: an early separation of Amazonia, and a later separation of the peri-Laurentian Dashwoods microcontinent (Waldron and van Staal, 2001; cf. Cawood et al., 2001). Within this context, the 0.590 Ga radiating swarm [#20b] (associated with the St. Lawrence rift system) may presage the separation of Amazonia from Laurentia at 0.57 Ga to form the Iapetus Ocean, and the magmatism at 0.563 Ga [#20c] may similarly be linked to the separation of the Dashwoods terrane ter·rane also ter·rain
1. A series of related rock formations.
2. An area having a preponderance of a particular rock or rock groups.
[Alteration of terrain.] at 0.550-0.540 Ga.
0.62-0.55 Ga (Avalon zone, Appalachians): The ca. 0.62 Ga Harbour Main Harbour Main, formerly Harbour Main-Whitbourne is a provincial electoral district for the House of Assembly of Newfoundland and Labrador, Canada. External links
0.57-0.52 Ga (Cordillera): The 0.57 Ga Hamill-Gog Group magmatism [#22a] in the southern Cordillera has been linked with a breakup along this Laurentian margin (Colpron et al., 2002).
In the northern Cordillera lower Paleozoic alkalic and potassic mafic magmatism [#22b] is linked with rifting of the Selwyn Basin (Goodfellow et al., 1995). This magmatism includes the Demster, Menzie Creek, Niddery volcanics, and younger Fossil Creek This article is about a creek in Arizona. For the creek in Colorado by the same name, see Fossil Creek (Colorado).
Fossil Creek is a perennial river in central Arizona. volcanics. The only precise age is a 0.518 Ga U-Pb age from a Post-Hyland Group sill, probably representing a widespread set of sills (Abbott, 1997). However, a range of volcanic ages from Lower Cambrian to Early Devonian In the geological timescale, the Early Devonian epoch (from 416.0 ± 2.8 million years ago to 397.5 ± 2.7 million years ago) occurred during the Devonian period, after the end of the Silurian period. is suggested on biostratrigraphic grounds (Goodfellow et al., 1995; Abbott, 1997).
0.47-0.41 Ga (Dunnage DUNNAGE, mer. law. Pieces of wood placed against the sides and bottom of the hold of a vessel, to preserve the cargo from the effect of leakage, according to its nature and quality. 2 Magens, 101, art. 125, 126 Abbott on Shipp. 227. , Gander Gander, town (1991 pop. 10,339), NE Newfoundland, N.L., Canada. Gander's airport, an important base in World War II, is a hub for international flights; it also attracts many refugees. It was the site of a Dec. , Avalon and Meguma zones, Appalachians): In Atlantic Canada several important mafic (and bimodal bi·mod·al
1. Having or exhibiting two contrasting modes or forms: "American supermarket shopping shows bimodal behavior ) magmatic suites include the 0.46 Ga Dunn Point [#23a], and 0.44-0.43 Ga Bayswater and Cape St. Mary's suites of the Avalon zone [#23b], the Middle Ordovician The Middle Ordovician (from 472 to 461 million years ago) is the second subdivision of the Ordovician period. During this time warm shallow sea covered much of the land, and was home to a rich diversity of marine life. Overstep Sequence of the Gander and Dunnage zones [#23a], the 0.44 Ga White Rock formation of the Meguma zone [#23b], and the early Silurian Overstep Sequence [#23b] of central Newfoundland (mainly in the Dunnage Zone). Much of this magmatism has been emplaced in a back-are setting. During this period the Iapetus Ocean was closing, but the spatial relationship between these Iapetan terranes is still under debate.
0.36-0.32 Ga: The Carboniferous Magdalen Magdalen: see Mary Magdalene. (or Maritimes) Basin is thought to have been underplated by a layer of mafic magma with an average thickness of 13 km based on geophysical ge·o·phys·ics
n. (used with a sing. verb)
The physics of the earth and its environment, including the physics of fields such as meteorology, oceanography, and seismology. modelling [#24a] (Marillier and Verhoef, 1989). In addition, volcanic rocks and intrusions of this age are distributed widely around the western and southern perimeter of the basin. The Magdalen Basin magmatic event [#24a] has been inferred to represent the final breakthrough of a plume that had been trapped beneath a subducting slab (Murphy et al., 1999).
0.27-0.21 Ga (Cordillera): The mid-Permian to upper Jurassic (ca. 0.27-0.20 Ga) Cache Creek There are several places named Cache Creek.
adj. tar·di·er, tar·di·est
1. Occurring, arriving, acting, or done after the scheduled, expected, or usual time; late.
2. Moving slowly; sluggish. et al., 2001 and Struik et al., 2001).
Wrangellia is an important accreted terrane of the Cordilleran orogen [#25b], consisting of Karmutsen and Nikolai volcanics and associated 0.232 Ga Maple Creek Maple Creek can refer to:
Long, curved chain of oceanic islands associated with intense volcanic and seismic activity and mountain-building processes. Examples include the Aleutian-Alaska Arc and the Kuril-Kamchatka Arc. Most island arcs consist of two parallel rows of islands. before being accreted onto the Cordilleran orogen (e.g. Richards et al., 1991).
Note that the Wrangell Lavas (0.065-0.002 Ga) (event #331 in Buchan and Ernst 2004), which extend from the Yukon into Alaska for a distance of -430 km, are distinct from the much older Wrangellia flood basalts, despite the similar names. The extensive Wrangell lavas are not catalogued in Table 1 because they are linked to subduction along the Aleutian are.
0.20 Ga: The largest magmatic event on Earth in terms of areal distribution is the Central Atlantic Magmatic Province The Central Atlantic magmatic province (CAMP) was formed during the breakup of Pangaea during the Mesozoic Era. The initial breakup of Pangaea in early Jurassic time provided a legacy of basaltic dikes, sills, and lavas over a vast area around the present central North Atlantic (CAMP) [#26a]. Found in North America, Europe, Africa and South America South America, fourth largest continent (1991 est. pop. 299,150,000), c.6,880,000 sq mi (17,819,000 sq km), the southern of the two continents of the Western Hemisphere. , it covers an area of nearly 7 million sq. km. It mainly consists of a giant radiating dyke swarm centred near Florida that was the precursor to the 0.175 Ga opening of the central Atlantic Ocean Atlantic Ocean [Lat.,=of Atlas], second largest ocean (c.31,800,000 sq mi/82,362,000 sq km; c.36,000,000 sq mi/93,240,000 sq km with marginal seas). Physical Geography
Extent and Seas
. Extensive sill provinces and volcanic packages are also found on all formerly adjacent blocks. In Atlantic Canada, this event is represented by several major dykes, as well as the North Mountain and Grand Manan Grand Manan (mənăn`), island c.16 mi (26 km) long and c.7 mi (11.3 km) wide, S N.B. Canada, in the Bay of Fundy. On the north and west sides are bold cliffs, rising from 200 ft to 400 ft (61–122 m) high, visible from the Maine coast. volcanics [#26a].
A plume origin seems most likely based on the large scale and short duration of the event as well as presence of a giant radiating dyke swarm. However, a model involving "edge convection" has also been advocated mainly on the basis of 'non-plume' chemistry, and the suggestion that the dykes represent a superposition su·per·po·si·tion
1. The act of superposing or the state of being superposed: "Yet another technique in the forensic specialist's repertoire is photo superposition" of distinct linear swarms rather than an overall single radiating swarm (e.g. several papers in Haines et al., 2003).
0.14-0.09 Ga: From 0.14 to 0.11 Ga there was extensive NEQ NEQ Numéro d'Entreprise du Québec (French: Québec Enterprise Number)
NEQ Net Explosive Quantity
NEQ New England Quarterly
NEQ Noise Equivalent Quanta
NEQ Northeast Qualifier (gaming tournament) (New England-Quebec) magmatic activity [#27a] in the eastern United States and Quebec. The Monteregian Hills The Monteregian Hills (French: Collines Montérégiennes) is a linear chain of isolated hills in Montreal and the Montérégie, between the Laurentians and the Appalachians. plutons and dykes of this magmatic event have been linked to a plume tail (the Great Meteor hotspot track) associated with the New England seamount chain The New England Seamount chain is an underwater chain of seamounts in the Atlantic Ocean stretching over 1,000 kilometers from the edge of the Georges Bank off the coast of Massachusetts southeast to the Bermuda Rise. (Heaman and Kjarsgaard, 2000). Problems with a plume origin for this magmatic province have been discussed by McHone (1996).
Another node of activity at this time is represented by the 400 km long Trap dyke swarm [#27b], which was emplaced along the southwestern coast of Greenland at 0.138 Ga. Given the proximity of Greenland to Labrador at this time, we would expect a continuation of this extensive magmatic event into eastern Canada Eastern Canada (also the Eastern provinces) is the region of Canada generally considered to be east of Manitoba, consisting of the following provinces:
[FIGURE 8 OMITTED]
Magmatism on the Queen Elizabeth Islands Queen Elizabeth Islands, northern part of the Arctic Archipelago, Northwest Territories and Nunavut, N Canada. Ellesmere Island (the largest), the Parry group (Melville, Bathurst, Devon, Prince Patrick, and Cornwallis islands), and the Sverdrup group (Axel Heiberg, [#27c] is part of the High Arctic Large Igneous Province The High Arctic Large Igneous Province (HALIP) is a major Late Cretaceous large igneous province located in the Arctic. It includes the Ellesmere Island Volcanics, Strand Fiord Formation, Alpha Ridge, Franz Josef Land and Svalbard. References
1. (HALIP) [#27c]. This event is also present in northern Greenland, Svalbard and Franz Josef Land Franz Josef Land (frăns jō`zəf, fränts yō`zĕf), Rus. Zemlya Frantsa Iosifa, archipelago, c.8,000 sq mi (20,720 sq km), in the Arctic Ocean N of Novaya Zemlya, Russia. , as well as offshore (Tarduno et al., 1998; Maher, 2001). Precise dates of 0.095-0.092 Ga apply to both the Strand Fiord fiord: see fjord. volcanics and the Wootton intrusion (Tarduno et al., 1998). However K-Ar and Rb-Sr dating as well as biostratigraphic control suggests that the magmatism may have begun at ca. 0.13 Ga. While a continuum of activity may be present, Maher (2001) interprets two pulses of activity, at ca. 0.13 and ca. 0.09 Ga. The identification of a radiating dyke swarm suggests a plume origin with a plume centre located near the Alpha Ridge
0.07-0.05 Ga: The 0.070 Ga Carmacks volcanics [#28a1 of the northern Cordillera have a slightly more potassic composition than most of the other events discussed in this paper, but they have a large areal extent (about 60,000 sq. km) and were apparently emplaced in a short duration. The slightly younger 0.06-0.05 Ga Crescent Terrane volcanics [#28b] consist of thick basaltic sequences distributed over a ca. 600 km distance along the Coast Ranges of western North America. They are inferred to represent accreted seamounts. Both the Carmacks volcanics [#28a] as well as the Crescent Terrane volcanics [#28b] have been interpreted as originating from earlier stages of the Yellowstone plume, prior to its main expression as the Columbia River Columbia River
River, southwestern Canada and northwestern U.S. Rising in the Canadian Rockies, it flows through Washington state, entering the Pacific Ocean at Astoria, Ore.; it has a total length of 1,240 mi (2,000 km). LIP at 0.017 Ga (see next entry, [#29b]) (e.g. Johnston et al., 1996; Murphy et al., 2003).
The North Atlantic igneous ig·ne·ous
1. Of, relating to, or characteristic of fire.
a. Formed by solidification from a molten state. Used of rocks.
b. Of or relating to rock so formed; pyrogenic. Province (NAIP NAIP National Agricultural Imagery Program
NAIP National Association of Inpatient Physicians
NAIP National Association of Investment Professionals
NAIP National Association of Independent Publishers
NAIP North Atlantic Ice Patrol ) [#28c] is most voluminous in eastern Greenland and the UK, and adjacent offshore regions. Minor activity at Cape Dyer and Cape Searle on Baffin Island, as well as more substantial magmatism in west Greenland are linked with the NAIP. The NAIP LIP is linked to the present-day Icelandic hotspot.
0.025-0.015 Ga: An important intraplate event is the widespread Behm Canal event [#29a] of the Cordillera, which is also known as the Tertiary Lamprophyre lam·pro·phyre
Any of several intermediate igneous rocks constituting feldspar and ferromagnesium minerals that occur as dikes and minor intrusions. Province. It consists of alkaline lamprophyres that are considered volatile-enriched equivalents of alkali alkali (ăl`kəlī) [Arab., al-gili=ashes of saltwort], hydroxide of an alkali metal. Alkalies are readily soluble in water and form strongly basic solutions with a characteristic acrid taste. basalts (Rock, 1991, p. 11-12, 122).
The voluminous Columbia River Basalt Group (CRBG) LIP [#29b] of the northwestern United States Noun 1. northwestern United States - the northwestern region of the United States
western United States, West - the region of the United States lying to the west of the Mississippi River was mainly erupted from 0.017 to 0.015 Ga. It has been linked to the Yellowstone plume. The coeval Chilcotin Group volcanics [#29c] are located a short distance to the north in Canada, and although they arc areally extensive they are volumetrically vol·u·met·ric
Of or relating to measurement by volume.
[volu(me) + -metric.]
Archean greenstone belts represent deformed and fragmented volcanic suites, and are of two main affinities: calc-alkaline and tholeiitic (e.g. de Wit and Ashwal, 1997; Condie, 2001; Blecker, 2002). The calc-alkaline suites are considered to be of arc origin whereas the tholeiitic suites, particularly those containing komatiites, are not. The presence of komatiites satisfies one requirement for the identification of LIPs, i.e. that they not be produced by subduction. In addition, greenstone belts with komatiites arc probably not produced by normal spreading ridge processes because komatiites indicate source region temperatures higher than those associated with normal spreading ridges. There is some controversy on this point since the Archean geotherm was hotter. The scale of Archean LIP candidates is also uncertain. In most cases deformation deformation /de·for·ma·tion/ (de?for-ma´shun)
1. in dysmorphology, a type of structural defect characterized by the abnormal form or position of a body part, caused by a nondisruptive mechanical force.
2. and faulting prevents the recognition of Archean tholeiitekomatiite greenstone belts over LIPscale distances. So the Archean LIP history, discussed below and summarized in Table 2 and Figure 1, remains speculative. Events are included in Table 2 on the basis of either the presence of komatiites, and/or inferred oceanic plateau setting.
[FIGURE 1 OMITTED]
3.11-2.98 Ga: The oldest known period of potential LIP activity is represented by komatiite-bearing greenstone belts (3.105 Ga Hunt River [#A1a] and 2.99-2.98 Ga Florence Lake Florence Lake (1 January 1904 – 11 April 1980) was an American actress who was the best known and most prolific of Edgar Kennedy's screen wives in his series of domestic short comedies which ran until 1948. [#A1b] belts) located in the Hopedale block of the Nain Province of the North Atlantic Craton. Another important magmatic event is associated with the ca. 2.99 Ga rifting [#A1c] of the ancient Archean nucleus in the western Superior Province comprising the North Caribou Caribou, town, United States
Caribou (kâr`ĭb), town (1990 pop. 9,415), Aroostook co., NE Maine, on the Aroostook River; inc. 1859. , Central Wabigoon and Marmion blocks (Tomlinson et al., 1999; Tomlinson and Condie, 2001).
2.93-2.92 Ga: A subsequent stage of komatiite-bearing greenstone belts [#A2a] at about 2.93-2.92 Ga is also widespread in the western Superior Province, but the setting and link with associated are-type greenstone belts is unclear.
2.86 Ga: The Pickle Crow greenstone belt [#A3a] in the Uchi subprovince is approximately dated at 2.86 Ga and contains komatiites.
2.79-2.77 Ga: The 2.786 Ga Vizien greenstone belt [#A4a] of northern Quebec contains komatiites and has been linked with formation of an oceanic plateau. Greenstone belt fragments (containing komatiites) within the Faribault-Thury Complex [#A4b] are also situated in northern Quebec, and are bracketed in age between 2.785 and 2.710 Ga. (Note that if future dating determines an age closer to the younger end of the age bracket, then the Faribault-Thury Complex event would be grouped in the next entry.)
The 2.775 Ga Fourbay sequence [#A4c] of the western Superior Province lacks komatiites, but is included in this LIP compilation because of its inferred oceanic plateau origin.
2.75-2.70 Ga: In various portions of the Canadian Shield there was widespread mafic magmatism falling in the age range 2.75-2.70 Ga. This is discussed in terms of three regional groupings.
It has been suggested that the Prince Albert Prince Albert, city (1991 pop. 34,181), central Sask., Canada, on the North Saskatchewan River. Prince Albert is a commercial and distribution center for a lumbering, gold- and uranium-mining, and mixed-farming area. There are wood-products and meatpacking industries. Group [#A5a] can be correlated with the Woodburn and Mary River groups, thus defining a single event in the Rae Province of northern Canada Northern Canada is the vast northernmost region of Canada variously defined by geography and politics. Definitions and usage
Also referred to as the Canadian North or (locally) as the North , which is distributed over a lateral distance of nearly 1000 km. The magmatism which includes komatiites is interpreted to have initiated at 2.73 Ga and may be associated with plume-generated continental breakup.
The Kam Group [#A5b] has been traced across large parts of the Slave Province through a complicated deformation pattern (Bleeker, 2003, and references therein). The magmatism of the Kam Group ranges from 2.734-2.700 Ga, and was particularly voluminous from 2.72-2.70 Ga.
Magmatism in the Abitibi greenstone belt The Abitibi greenstone belt is a 2,800-2,600 million year old greenstone belt that spans across the Ontario-Quebec border in Canada. It is mostly made of volcanic rocks, but also includes ultramafic rocks, mafic intrusions, granitoid rocks, and early and middle Precambrian [#A5c] of the central Superior Province is widespread and consists of four distinct stages of komatiite-associated magmatism cmplaced during the interval 2.75-2.70 Ga (e.g. Sproule et al., 2002). The interspersed calc-alkaline magmatism suggests a plume arc association (e.g. Wyman, 1999). The Schreiber-Hemlo-White River-Dayohessarah packages found in the Wawa greenstone belt [#A5d], also contain significant komatiite-bearing tholeiitic magmatism with ages between 2.75 and 2.73 Ga. The Wawa belt is on strike with and is probably the continuation of the Abitibi belt.
As described above, Canada has a rich LIP history consisting of at least 80 possible events (Fig. 1, Tables 1 and 2). They range from Archean greenstone belts (containing komatiites) such as the Prince Albert Group and probable correlatives, which may extend for >1000 km along the Rae Province, through Proterozoic giant radiating dyke swarms, such as the Mackenzie swarm that covers nearly 3,000,000 sq. km of the Canadian Shield, to young flood basalts, such as the rift-related Keweenawan Group and the accreted oceanic plateau, Wrangellia, in the Cordillera. LIPs are key to resolving a number of important geological issues and processes. Here we apply our database of Canadian LIPs to several frontier issues.
Plume vs. Non-plume Origins
As mentioned earlier, there is currently an intense debate about plume versus non-plume origins for LIPs. This debate is occurring both on the web (e.g. www.mantleplumes.org; www.largeigneousprovinces.org) and in the scientific literature (e.g. Anderson, 2001; Foulger and Natland, 2003; DePaolo and Manga maNga is a popular Turkish nu metal/rapcore band. Their music is mainly a fusion of alternative metal and hip hop music, with a touch of Anatolian melodies; with heavy use of turntables, invoking comparisons with modern American nu metal bands. , 2003; Ernst et al., 2004). The Canadian LIP database can contribute to this debate in various ways. Giant radiating dyke swarms are strongly indicative of mantle plumes (e.g. Ernst and Buchan, 1997). Using this criteria, plumes would be inferred at 2.45, 1.27, 0.78, 0.72, 0.20 Ga. Furthermore, many Canadian swarms have a failed-arm (aulacogen setting) (Fig. 3b, Table 3), which also suggests plume involvement. In addition, Archean greenstone belts, which contain komatiites, are arguably plume-related. Finally, recognition of additional mantle plumes may also derive from studies of regional uplift patterns (see below). On the other hand, some LIPs having a linear distribution, such as those in a back-arc setting, may be consistent with non-plume origins. Those along a breakup margin may be generated by decompression melting accompanying rifting. Some LIPs may consist of two pulses, an initial burst of magmatism associated with plume arrival and a second caused by the onset of decompression melting associated with breakup.
[FIGURE 3 OMITTED]
Precise Time Markers for Stratigraphic Correlation
The wide distribution (potentially over millions of sq. km) and the typically short duration of events makes them ideal as precise stratigraphic markers (e.g. LeCheminant and Heaman, 1989; Harlan et al., 2003b). For instance, recognition of the same magmatic event within widely separated sedimentary sed·i·men·ta·ry also sed·i·men·tal
1. Of, containing, resembling, or derived from sediment.
2. Geology Of or relating to rocks formed by the deposition of sediment. sequences represents an ideal marker for inter-basin correlation. In Canada, the 1.27 Ga Mackenzie, 0.78 Ga Gunbarrel, and 0.72 Ga Franklin LIPs represent particularly good markers.
Reconstruction of Continents
Globally there is a clear link between young LIPs and breakup margins (e.g. Courtillot et al., 1999). The Canadian landmass land·mass
A large unbroken area of land.
a large continuous area of land
landmass preserves a history of continental breakup, and subsequent reassembly reassembly - segmentation marked by sutures. Therefore, the Canadian LIP record is fertile ground for exploring links with breakup events. Archean continental fragments each contain a particular age distribution of mafic events (mostly Proterozoic dyke swarms) that represent a distinct "bar code" (Bleeker, 2003, 2004). Comparison of the "bar code" from the approximately 35 different Archean continental fragments (at least eight of which are in Canada) represents a key tool for proposing reconstructions between these fragments. Reconstructions can be tested by comparing the paleomagnetism of coeval mafic units on the different continental fragments (Buchan et al., 2000). In addition, linear (Fig. 4a) and radiating (Fig. 4b) dyke swarms can be used to constrain con·strain
tr.v. con·strained, con·strain·ing, con·strains
1. To compel by physical, moral, or circumstantial force; oblige: felt constrained to object. See Synonyms at force.
2. the reconstruction geometry. Some suggested correlations are given in Tables 1 and 2, and in the accompanying text.
[FIGURE 4 OMITTED]
Exploration (Ni-Cu-PGEs and Diamonds)
Ni-Cu-PGE deposits are commonly associated with LIPs. Notable examples include the Siberian Traps and the Bushveld bushveld
S African bushy countryside [Afrikaans] Complex (e.g. Naldrett, 1999; Pirajno, 2000; Diakov et al., 2002; Hulbert, 2002). Ernst and Hulbert (2003) carried out a preliminary analysis of background PGE levels in about 60 Canadian LIPs and other intraplate mafic events in order to assess which are more likely to host such deposits. Events with elevated background PGE levels (>10 ppb ppb
parts per billion Pt and Pd) are thought to have greater potential for enrichment during magmatic emplacement. Ernst and Hulbert (2003) found that events with high background levels include the 2.50-2.45 Ga Matachewan, 2.22-2.21 Ga Ungava-Nipissing, 1.27 Ga Mackenzie, 0.72 Ga Franklin, 0.59 Ga Grenville and portions of the 1.11-1.09 Ga Keweenawan and 0.13-0.09 Ga Sverdrup Basin events.
Some studies have proposed a direct link between kimberlites and underlying plumes (Haggerry, 1999; Heaman and Kjarsgaard, 2000; Schissel and Small, 2001). Recently it has also been suggested that some kimberlites might be preferentially localized along particular dyke swarms such as the 2.023 Ga Lac de Gras swarm of the Slave Province (Wilkinson et al., 2001; Stubley, 2003) and the 2.50-2.45 Ga Matachewan dykes of the Attawapiskat region in the James Bay lowlands (Stott and Halls, 2002). Further work is required to test the potential of fractures and zones of weakness represented by major dyke swarms to localize lo·cal·ize
v. lo·cal·ized, lo·cal·iz·ing, lo·cal·iz·es
1. To make local: decentralize and localize political authority.
2. kimberlite kimberlite: see diamond.
or blue ground
Dark, heavy, often fragmented igneous rock that may contain diamonds in the rock matrix. magmas during their ascent through the crust.
Numerous studies have explored the link between LIPs and climate change (e.g. Condie, 2001; Isley and Abbott, 2002; Courtillot and Renne, 2003; Ernst and Buchan, 2003, Prokoph et al., 2003). The correlation between extinction events For the Big Finish Productions audio play, see .
An extinction event (also known as: mass extinction; extinction-level event, ELE) is a sharp decrease in the number of species in a relatively short period of time. and LIPs is compelling (Courtillot et al., 1996; Courtillot and Renne, 2003) and suggests that some LIPs, perhaps acting in concert with meteorite meteorite, meteor that survives the intense heat of atmospheric friction and reaches the earth's surface. Because of the destructive effects of this friction, only the very largest meteors become meteorites. impact events, may be the trigger for extinction events. Evaluation of a robust Canadian HP record can contribute to the global understanding of the effect of LIPs on climate. For instance, all other factors being equal, the largest LIP events should have the largest climatic effect. Some of the largest LIPs in Canada are the ca. 1.88 Ga Circum-Superior, 1.27 Ga Mackenzie, 0.72 Ga Franklin, 0.615-0.555 Ga Central Iapetus, and 0.20 Ga CAMP events. Only the climatic effect of the youngest of these events has been evaluated (Palfy 2003).
Regional Domal Uplift
LIPs linked to mantle plumes should be associated with regional domal uplift. The scale of uplift corresponds to the size of the plume head (e.g. Cox, 1989; Rainbird rainbird
S African a common name for [Burchell's coucal], a bird whose call is believed to be a sign of impending rain and Ernst, 2001; Campbell, 2001; Sengor, 2001; He et al., 2003). The largest plumes are thought to generate uplifts with a radius 1000 km and a peak elevation 1 to 2 km. Such uplifts should exert a first-order control In control theory, first-order control is when a desired result is attempted by adjusting a scalar (first-order) control. Such mechanisms, where first-order change successfully produces desired results, are called first-order mechanisms. on concurrent regional sedimentation sedimentation
In geology, the process of deposition of a solid material from a state of suspension or solution in a fluid (usually air or water). Broadly defined it also includes deposits from glacial ice and materials collected under the effect of gravity alone, as in talus patterns. Plume head related uplift has only received preliminary investigation in Canada, where it has been associated with 1.27 Ga Mackenzie, 0.72 Ga Franklin, and 0.615-0.555 Ga Central Iapetus events (e.g. Rainbird and Ernst, 2001). It is hoped that the LIP database for Canada will stimulate further investigation of regional uplift patterns.
EXPANDING THE LIP DATABASE TO ADDRESS FRONTIER ISSUES
The frontier issues discussed above can only be fully addressed using a more robust LIP record. Although an extensive database is presented in this paper, many major mafic and ultramafic ul·tra·maf·ic
Containing mainly mafic minerals. Used of igneous rocks and often used interchangeably with ultrabasic. Dunite is an ultramafic rock. units remain undated and poorly characterized. Rapid improvement in the LIP database can be achieved only through a concerted campaign of geochronology integrated with other fields such as paleomagnetism and geochemistry, as is being proposed for Canada by Bleeker (2004) and internationally by Ernst et al. (2004).
Table 1 Large Igneous Provinces (LIPs) and potential LIPs in Canada and adjacent regions since 2.5 Ga. Names of the largest events are underlined. Obsolete names in square brackets. Pre-2.5 Ga record is discussed in Table 2. Anorthosites have not been included. Details and full referencing on most events are available in compilations  (=Ernst and Buchan, 2001) and  (=Buchan and Ernst, 2004), or in the additional cited references. Abbreviations: se. = southeast, ne. = northeast, c. = central, etc. Units in each entry are ordered in terms of decreasing size. "REF.:" = key reference(s). SETTING codes are explained in Table 3. Event name Magmatic components (Age) (Age) (Location) [Size] 1 2.51-2.41 Ga 1a Mistassini (-2.5 Ga) DYKES: Mistassini (-2.5 Ga) (e. Superior Prov.) REF.: #204 in ; #43 in  [100,000 sq. km] COMMENT: ?Link with Ptarmigan swarm (2.51 Ga [#35 in ] of ne Superior Prov. ?Link with Du Chef swarm (2.41 Ga) [#45 in ] along Grenville Front SETTING: Plume (P1); Breakup (B1; se. Superior Craton) 1b Matachewan DYKES: Matachewan [Hearst] (2.49-2.45 Ga) (2.47 and 2.45 Ga) (s. & e. Superior Prov.) LAYERED INTRUSIONS: East Bull [360,000 sq. km] Lake (2.48 Ga); Agnew (2.49 Ga); River Valley (2.475 Ga); Falconbridge Twp (2.44 Ga) VOLCANIC ROCKS: Dollyberry; Ellise Mountain; Copper Cliff rhyolites (-2.45 Ga); Thessalon. REF.: #206 in ; #42 in  COMMENT: ? Link with Ptarmigan swarm (2.51 Ga [#35 in ] of ne. Superior Craton) SETTING: Plume (P1); Breakup (B1; s. Superior Craton) 1c Kaminak DYKES: Kaminak (-2.45 Ga) (ca. 2.45 Ga REF.: #203 in ; #44 in  (Hearne Prov.) SETTING: Plume (?P1); ?Breakup [18,000 sq. km] (Hearne Craton) COMMENT: Linked with Matachewan event [#1b] by Bleeker (2004) 1d Mirond Lake (2.49 Ga) DYKES: Mirond Lake (2.49 Ga) (Trans Hudson) REF.: #41 in  [two 'windows' into SETTING: ?Breakup (Sask Craton) Archean basement about 120 km apart] 2 2.24-2.21 Ga 2a Kikkertavak DYKES: Kikkertavak (2.235 Ga) (2.235 Ga) REF.: #47 in  (Makkovik Prov.) COMMENT: Linked with Lower Aillik [6500 sq. km] Group (2.18 Ga) rift magmatism [Ketchum et al., 2001] SETTING: ?Breakup (s. North Atlantic [Nain] Craton) 2b BN-1 (2.21 Ga) DYKES: BN-1 (norite) (2.21 Ga); (s. Greenland) MD-1 undated but possibly similar [54,000 sq. km] in age REF.: #193 in ; #40 in  SETTING: ?Breakup (? North Atlantic [Nain] Craton) 2c Ungava DYKES: Ungava radiating swarm = (2.22-2.21 Ga) Senneterre (2.22 Ga), Maguire (ne. and e. and Klotz (2.21 Ga) Superior Prov.) SILLS: Nipissing (2.22 Ga) [500,000 sq. km] REF.: #191 in ; #50-52 in  SETTING: Plume (P1); Breakup (B1, e. Superior Craton) 2d Malley-MacKay DYKES: Malley NE trend (2.23 and 2.21 Ga) (-2.23 Ga)]; MacKay ENE-E (Slave Prov.) trend (-2.21 Ga) [35,000 sq. km] REF.: #192 and #197 in ; #48 and #57 in  SETTING: Breakup (Slave Craton) 3 2.19-2.17 Ga 3a Dogrib (2.19 Ga) DYKES: Dogrib (2.19 Ga) (Slave Prov.) SILLS: Duck Lake (2.18) [11,000 sq. km] REF.: #185 in ; #60 in ; Bleeker & Kamo, 2003 SETTING: Breakup (Slave Craton) 3b Tulemalu-MacQuoid DYKES: Tulemalu-MacQuoid (2.19 Ga) (2.19 Ga) REF.: #186 in ; #61 in  (Hearne Prov.) SETTING: Breakup (Hearne Craton) [15,000 sq. km] 3c Biscotasing (2.17 Ga) DYKES: Biscotasing (2.17 Ga) (Superior Prov) REF.: #184 in ; #64 in ; [350,000 sq. km] Halls and Davis, 2004 SETTING: Plume (P3) 3d Cramolet MAGMATISM: 'Cycle 1', including Lake-Payne River Cramolet Lake sill of basal (2.17 Ga) Seward Subgroup (2.17 Ga) (New Quebec Orogen) DYKES: Payne River -2.17 Ga [30,000 sq. km] [S. Pehrsson, pers. comm., 2000] REF.: #63 in  SETTING: Breakup (B2, e. Superior Craton) 4 2.12-2.07 Ga 4a Marathon DYKES: Marathon-N (2.12 Ga); (2.12-2.10 Ga) Marathon-R (2.10 Ga) (c. Superior Prov.) REF.: #180 & 181 in ; #69 in  [60,000 sq. km] SETTING: Plume (P2); Breakup (B1, either nc. or sc. Superior Craton) 4b Cauchon Lake DYKES: Cauchon Lake (2.09-2.07 Ga) (includes Birthday Rapids) (nw. Superior Prov.) (2.09 and 2.07 Ga) REF.: #175 in ; #72 in  SETTING: ?Breakup (B2, nw. Superior Craton) 4c Fort Frances DYKES: Fort Frances (2.08 Ga) (2.075 Ga) REF.: #174 in [l]; #73 in  (sw. Superior Prov.) SETTING: Plume (P2); Breakup [75,000 sq. km] (B1, sc. Superior Craton) 4d Lac Esprit (2.07 Ga) DYKES: Lac Esprit (2.07 Ga) (ne. Superior Prov.) REF.: #74-75 in , Buchan et al., 2004 SETTING: Plume (P2); ?Breakup (B1, nc. Superior Craton) 4e Griffin (2.11 Ga) SILLS: Griffin [Hurwitz] (2.11 Ga) (Hearne Prov.) REF.: #179 in ; #70 in  [80,000 sq. km] SETTING: Plume (P3); ?Breakup (Hearne Craton) 4f Napaktok (?2.12 Ga) DYKES: Napaktok (<2.13 Ga); (Labrador Coast) Tikkigatsiagak (2.12 Ga); ?Domes REF.: #182 in ; #68 in  SETTING: ? 5 2.05-2.02 Ga 5a Kangamuit DYKES: Kangamuit (of Greenland) (2.05-2.04 Ga) (2.04-2.05 Ga); Iglusuataliksuak (wc. Greenland; (2.05 Ga) Nain Prov.) REF.: #170 in ; #80 in ; [20,000 sq. km] [#78 in  SETTING: Breakup (?B2, n. North Atlantic [Nain] Craton) 5b Lower Povungnituk VOLCANIC ROCKS: Lower Povungnituk (2.04 or 1.96 Ga) SILLS: Korak [2.04 Ga) (Cape Smith Belt, REF.: #169 in ; ne. Superior Prov.) Modeland et al., 2003 SETTING: Breakup (B3, n. Superior Craton) 5c Hearne (2.04 Ga) DYKES: Hearne (2.04 Ga) (Slave Prov.) REF.: #168 in ; #81 in  [15,000 sq. km] SETTING: Breakup (B2, s. Slave Craton) 5d Lac de Gras DYKES: Lac de Gras (2.02-2.03 Ga) (ca 2.025 Ga) LAYERED INTRUSION: Booth River (Slave Prov.) Complex (2.02 Ga) [30,000 sq. km] REF.: #167 in , #82 in  SETTING: ?Plume (P3) 6 2.00-1.95 Ga 6a Minto-Eskimo DYKES: Minto (2.00 Ga); Inukjuak (2.00 Ga) VOLCANIC ROCKS: Eskimo; Persillon (e. Hudson Bay, (Pachi); Nastapoka Group ne. Superior Prov.) OPHIOLITE: Watts Group (2.00 Ga) [10,000 sq. km REF.: #162 in ; #88 and #92 for dykes only] in ; Scott et al., 1999 COMMENT: geochemically linked with western Povungnituk (2.04 Ga) by Legault et al. (1994) SETTING: Plume (P3); ?Breakup (nc. Superior Craton) 6b Flaherty-Haig VOLCANIC ROCKS: Flaherty (?1.96 Ga) (? -1.96 Ga) (e. Hudson Bay) SILLS: Haig; Sutton Inlier; Sleeper Island REF.: #161 in ; Chandler and Schwarz, 1980; Schwarz, and Fujiwara, 1981 COMMENT: linked with eastern Povungituk (1.96 Ma) by Legault et al. (1994) SETTING: ?Breakup (B3, nc. Superior Craton) 6c Upper Povungnituk VOLCANIC ROCKS: Upper Povungnituk (ca. 1.96 Ca) (1.96 Ga) (Cape Smith Belt, REF.: #169 in ; Pehrsson per. ne. Superior Prov.) comm., 2000; Legault et al., 1994; Modeland et al., 2003 SETTING: Breakup (B3, n. Superior Prov. at 2.04 Ga) 6d Mugford (1.95 Ga) VOLCANIC ROCKS: Mugford (Nain Prov.) (-1.95 Ga); ?Ramah; ?Snyder 400 sq. km 1.2 km thick REF.: #159 in ; Hamilton pers. comm., 2000 SETTING: ? Rifting 7 1.90-1.88 Ga (in Trans Hudson and adjacent Rae-Hearne Craton) 7a Sandy Bay VOLCANIC ROCKS: oceanic plateau (Sandy (1.90 Ga) Bay), oceanic island basalts and ocean (Flip Flon belt) (Trans floor assemblages Hudson Belt) REF.: #154 in ; Syme et al., 1999; Stern et al., 1999 SETTING: ? Plume (P6) 7b Josland (1.88 Ga) SILLS: Josland Lake including Mikanagan (Amisk collage, Trans Hudson) (1.89-1.88 Ga) REF.: Stern et al. 1999; Zwanzig et al., 2001; Turek et al. 2000 SETTING: Back-arc (A2) 7c Bravo Lake (1.90-1.88 Ga) VOLCANIC ROCKS AND SILLS: Bravo Lake (Piling-Penhryn Group, Rae (1.90-1.88 Ga) Prov.) REF.: Jackson and Taylor, 1972; Scott et al., 2002 SETTING: Rift 7d Lake Harbour VOLCANIC ROCKS AND SILLS: Lake Harbour (-1.87 Ga) Group (~1.87 Ga) (Lake Harbour Group, Rae REF.: St-Onge et al., 2000 Prov.) SETTING: Rifting and breakup of the Meta Incognita microcontinent from the northern Superior Craton [St-Onge et al., 2000] 8 1.88-1.86 Ga (Circum-Superior events) 8a New Quebec-Cycle 2 VOLCANIC ROCKS AND SILLS: 'Cycle 2' (1.88 Ga) SILLS: Montagnais (1.88-1.87 Ga) (New Quebec orogen) REF.: #151 in  [30,000 sq. km] SETTING: Back Arc (A1) 8b Chukotat VOLCANIC ROCKS: Chukotat (lower portion (1.89-1.87 Ga) are komatiitic basalt,) (1.87 Ga) (Cape Smith Belt, ne. SILLS: Katniq sills (1.92 or ~1.89 Ga) Superior Prov.) REF.: #153 in ; N. Wodicka, pers. comm., 2004 SETTING: Plume (P4) 8c Molson-Thompson DYKES: Molson (1.88 Ga); Pickle Crow (1.88-1.86 Ga) (1.88 Ga) (Thompson Belt; nw. Superior SILLS: Fox River (1.88 Ga); Thompson Prov.) Nickel Belt magmatism [>30,000 sq. km] KOMATIITES: Winnipegosis (1.86 Ga) REF.: #150 in [l]; #85 and #98 in ; Hulbert et al., 1994; Buchan et al., 2003; Hulbert er al., 2004 SETTING: Plume (?P1, P4); Back-arc (A1) 8d Hemlock VOLCANIC ROCKS: Hemlock put (1.87 Ga); (1.88 Ga) Gunflint Fm. (1.88 Ga); Badwater (Animikie Basin--Marquette Greenstone Range, Southern Prov.) SILLS: Kiernan REF.: Ueng et al., 1988; Schneider et al., 2002; Fralick et al., 2002 SETTING: Rifting or Foredeep 9 1.83-1.82 Ga 9a Sparrow DYKES: Sparrow (1.83 Ga) (1.83 Ga) GABBRO BODIES: In Wollaston-Mudjatik (Rae Prov.) Transition zone (1.83-1.82 Ga) [100,000 sq. km] REF.: #146 in  & #101 ; Annesley et al., 2003 COMMENT: Is there a link with Christopher Island Fm (Baker Lake basin) (Cousens er al., 2001; Peterson et al., 2002)? SETTING: ? Breakup (Rae Craton) 10 1.75-1.71 Ga l0a Cleaver (1.75-1.74 Ga) DYKES: Cleaver (1.74 Ga); Hadley Bay (Bear and Rae Pov.) (~1.75 Ga) and MacRae Lake (~1.75 Ga) [three locations spanning an REF.: #105-107 in ; Irving et al., area of 300,000 sq. km] 2004 COMMENT: Is this event a precursor to Bonnet River dykes and stocks, and Slab volcanics (1.71 Ga), which have been linked with Wernecke Supergroup (Thorkelson et al., 2001)? Is there a link to Pitz Fm and Nueltin Intrusive Suite of Baker Lake area (Turner et al., 2003; Peterson et al., 2002)? SETTING: ? Plume (P3) Breakup (preceeding breakup of nw. Laurentia) 10b Winagami (?1.89-1.76 Ga) SUBSURFACE SHEETS: Winagami (1.89-1.76 (Western Canada Basin) Ga). [120,000 sq. km] REF.: #149 in  COMMENT: Imaged seismically; possible link with Cleaver dykes suggested by Ross and Eaton (1997) SETTING: ? Plume (P3) 11 1.64 Ga 11a Melville Bugt (ca. DYKES: Melville Bugt (~1.64 Ga) 1.64 Ga) REF.: #132 in ; Hamilton et al., 2004 (w. Greenland) SETTING: ? [220,000 sq. km] 12 1.47-1.44 Ga 12a Moyie (1.47 Ga) SILLS: Moyie (Purcell) (1.47 Ga) (Belt-Purcell basin, VOLCANIC ROCKS: Purcell Cordillera) DYKES: Tobacco Root (Wyoming Block-1) [120,000 sq. km dykes only] (1.46 Ga) REF.: #124 in ; #117 in  SETTING: Plume (P2); Breakup (w. or sc. Laurentia) 12b Michael-Shabagamo (ca. SHEETS: Michael Gabbro (~1.47 Ga); 1.47 Ga) Shabagamo (~1.46, 1.45 Ga) (ne. Grenville Prov.) REF.: Corrigan et al., 2000; Krogh, 1993 [two regions spanning 50,000 in Gower and Krogh, 2002; #122 in ; sq. km] #119-120 in  SETTING: Back-arc (A1) 13 1.38 Ga 13a Hart River-Salmon River VOLCANIC ROCKS and SILLS: Hart River Arch (1.38 Ga) of n. Cordillera; Salmon River (1.38 Ga) Arch (1.38 Ga) of s. Belt Basin (n. Cordillera and s. Belt REF.: entry in Table 4 of ; #121 Basin) in  SETTING: ? Plume (P2) ? Breakup (nw. Laurentia) 14 1.28-1.27 Ga 14a Mackenzie (1.27 Ga) DYKES: Mackenzie (radiating swarm) (1.27 (Canadian Shield) Ga); Bear River (127 Ga); '305' [2,700,000 sq. km] VOLCANIC ROCKS: Coppermine; Ekalulia; Nauyat; Hansen; Tweed Lake SILLS: Christie Bay; Tremblay; Goding Bay LAYERED INTRUSIONS: Muskox (1.27 Ga) REF.: #107 in ; 140, 142, 143 in ; Sevigny et al., 1991; French et al., 2002; Schwab et al., 2004 SETTING: Plume (P1); Breakup (B1, n. Laurentia) 14b Harp-Nain-Nutak-middle DYKES: Nain-LP (1.28 Ga); Nutak (1.27 Gardar Ga); Nain-HP; Harp (1.27 Ga) Gardar-BDO 1.28 and 1.27 Ga (~1.28 Ga) Gardar-BD1 (North Atlantic Craton) REF.: #108 in ; #132, #133, #137, (Nain Prov. and s. Greenland) #138, #139 and #141 in  [80,000 sq. km] SETTING: ?Breakup (se. Laurentia) COMMENT: The anorthosites, diorites, granites, and troctolites of the 1.35-1.29 Ga Nain Plutonic Suite [e.g. Ryan and James, 2004] which cover an area of 20,000 sq. km in Labrador, are unrelated 15 1.25-1.225 Ga (Grenville Province) 15a Sudbury [dykes] (1.24 Ga) DYKES: Sudbury (1.24 Ga) (Superior and Grenville REF.: #104 in ; #146 in  Prov.) SETTING: Plume (P2); Back-arc (A1) [90,000 sq. km] 15b Seal Lake-Mealy (1.25 Ga) VOLCANIC ROCKS: Seal Lake (Grenville Prov.) SILLS: Naskaupi (1.25 and 1.22 Ga) [20,000 sq. km] DYKES: Mealy (1.25 Ga) North West River. REF.: #105 in ; #113, #144, & #144a in  SETTING: Back-arc (A1) 16 1.18-1.14 Ga 16a Davy Group-Tshenukutish- SILLS AND DYKES: Davy Group in Wakeltam Algonquin rift (1.18 Ga); Lillian Suite (1.18-1.16) CORONITIC GABBRO: in Baie du Nord (Grenville Prov.) segment of Tshenukutish domain (1.17 Ga) METAGABBROS: Algonquin metagabbros in Central Gneiss Belt (~1.17 Ga) DYKES: Kingston (~1.16 Ga) REF.: #97 in ; #145, #147 & #149 in  COMMENT: Widely separated events in Grenville Prov. of the same age SETTING: Back-arc (A1) 16b Late Gardar (1.16 Ga) DYKES: Tugtutoq Giant Dykes (1.18 and (North Atlantic Craton, 1.16 Ga) southern Greenland) REF.: Buchan et al., 2000; Upton et al., 2003 SETTING: Breakup (?) 16c Abitibi [dykes] (1.14 Ga) DYKES: Abitibi (1.14 Ga) (Superior Prop.) REF.: #94 in ; #155 in  [240,000 sq. km] SETTING: Plume (P1); Breakup (? precursor to Keweenawan) 17 1.11-1.09 Ga 17a Keweenawan (Mid-continent VOLCANIC ROCKS, SILLS AND DYKES: rift system) Keweenawan (1.11-1.09 Ga; main pulses, (1.11-1.09 Ga; main pulses: 1.107 and 1.097 Ga). 1.11, 1.10 Ga) REF.: #90 in ; #158-170 in  (Southern Prov.) COMMENT: ?Relationship with Southwestern [160,000 sq. km] USA Diabase Province [#89 in ]; and Moores Lake sills (1.11 Ga) in Athabasca basin [French et al., 20021. ?Link with Umkondo event of Africa [#91 in ; Hanson er al., 2004] SETTING: Plume (P3) Breakup (attempted breakup of Laurentia) 18 0.78 Ga 18a Gunbarrel (0.78 Ga) SHEETS: Hottah (sheets) (0.78 Ga) (Slave Prov; Mackenzie Mtns. VOLCANIC ROCKS: Huckleberry; Irene (ca. of n. Cordillera; Wyoming 0.76 Ga) Prov.) SILLS: Faber Lake Gabbro (0.78); Wolf [several areas spanning a Creek (0.78 Ga); Mackenzie Mountains distance of about 2500 km] DYKES (0.78 Ga): MacDonald; Mackenzie Mountains; Tobacco Root-Group B REF.: #63 in ; #178-181 in ; Harlan et al., 2003b COMMENT: ?Link with Windermere rifting [#77 in ]; Both South China and Australia have been proposed as the rifted block(s) SETTING: Plume (P1); Breakup (B1, w. Laurentia) 19 0.72 Ga 19a Franklin-Thule (0.72 Ga) VOLCANIC ROCKS: Natkusiak Arctic Islands, mainly Baffin DYKES: Franklin (0.72 Ga); Thule (of Island also n. Superior Greenland) Prov.) SILLS: (0.72 Ga) Minto Inlier; [1,100,000 sq. km for Coronation; Dybbol; Banks Island; Canadian portion] Steensby Land (of Greenland) REF.: #58 in  and #185-186 in  COMMENT: Note 0.69 Ga Gataga and Hyland Group volcanics of northern Cordillera [Ferri et al., 1999; Colpron et al., 2002]. Do these represent subsequent rifting associated with the Franklin-Thule event? SETTING: Plume (P1); ?Breakup (B1, n. Laurentia) 20 0.615-0.56 Ga Central Iapetus (Laurentian margin, Event [Puffer 2002] Appalachians) 20a Long Range (0.62 Ga) DYKES: Long Range (0.62 Ga) (e. North America) VOLCANIC ROCKS: Lighthouse Cove [105,000 sq. km] REF.: #54 in ; #192 in  SETTING: ?Plume ?Breakup (B2, e. Laurentia from Baltica) 20b Grenville-Rideau (0.59 DYKES: Grenville (0.59 Ga)-Rideau- Ga) Adirondack (fanning swarm) (e. North America) REF.: #53 in ; #194-196 in  [140,000 sq. km] SETTING: Plume (P1); ?Breakup (B1, e. Laurentia from ?Amazonia) 20c Sept-Iles-Catoctin (0.56 LAYERED INTRUSION: Sept-Iles (0.56 Ga) Ga) VOLCANIC ROCKS: Skinner Cove; Catoctin (e. North America) (in US Appalachians) (0.56 Ga) REF.: #52 in  SETTING: ?Plume (P3); ?Breakup (e. Laurentia from Dashwoods Terrane) 21 0.62-0.55 Ga (Avalon terrane, Appalachians) 21a Harbour Main VOLCANIC ROCKS: part of Harbour Main (ca. 0.62 Ga) Group (0.63-0.59 Ga) (Avalon Zone, Appalachians) INTRUSIONS: Holyrood granite suite (0.62 Ga); Connaigre Bay Group (0.63 Ga); Simmons Brook suite (0.62 Ga); Cap au Miquelon Group (ca. [greater than or equal to] 6.2 Ga); East Bay Hills Belt (ca. 0.62 Ga); Coxheath Hills Belt (ca. 0.62 Ga) REF.: Rabu et al., 1996; Bevier et al., 1993 SETTING: ? 21b Marystown VOLCANIC ROCKS: Marystown Group (0.59-0.55 Ga) (0.59-0.575 Ga); Long Harbour Group Avalon Zone, Appalachians) (0.57-0.55 Ga); St. Pierre Group (0.58 Ga); Belle Riviere Group (0. 57 Ga); part of Harbour Main Group (0.63-0.59 Ga); Coastal Belt (0.58 Ga) REF.: p. 15, O'Brien et al., 1996; Rabu et al., 1996; Bevier et al., 1993; Fig. 3 in McNamara et al., 2001 SETTING: Arc/ back-arc 22 0.57-0.52 Ga (Cordillera) 22a Hamill-Gog (0.57 Ga) VOLCANIC ROCKS: Hamill-Gog Group (SE Canadian Cordillera) (0.57 Ga) REF.: Colpron et al., 2002 SETTING: ?Breakup 22b Selwyn Basin (0.54-0.45 SILLS: Post-Hyland Group (0.52 Ga) Ga) VOLCANIC ROCKS: Alkali and potassic (Cordillera, n. of and within mafic volcanism Selwyn Basin) REF.: #218 in ; Goodfellow et al., 1995; Abbott, 1997 SETTING: Selwyn Basin rifting 23 0.47- 0.42 Ga (Appalachians) 23a Middle Ordovician VOLCANIC ROCKS: Middle Ordovican 'Overstep' Sequence Overstep Sequence' includes bimodal (0.47-0.45 Ga) magmatism (in Exploits subzone of (Gander Zone-Dunnage Zone) Newfoundland, Bathurst area of New Brunswick, Maine, and United Kingdom) (0.47-0.45 Ga) REF.: van Staal et al., 1996 COMMENT: Coeval Dunn Point bimodal volc. (0.46 Ga) occur in the Avalon terrane, Nova Scotia (Hamilton and Murphy, 2004) SETTING: Back-arc 23b Late Ordovician-Silurian GANDER ZONE-DUNNAGE ZONE (of New magmatism of Atlantic Canada Brunswick, Quebec and Maine) (0.43-0.41 (11.44-11.41 Ga) Ga) (e. Newfoundland and VOLCANIC ROCKS: Tobique and Piscataquis Maritimes) volcanic belts REF.: Keppie and Dostal, 1994 AVALON ZONE (of Nfld. and New Brunswick) (0.44-0.43 Ga) SILLS: Cape St. Mary's (0.44 Ga) VOLCANIC ROCKS: Bayswater Group (0.44 Ga); Coastal Volcanic Belt (0.43-0.42 Ga) DYKES: Kingston Terrane dyke complex (0.44-0.41 Ga); Passamaquoddy Bay REF.: Van Wagoner et al., 2001; Barr et al., 1999; Hodych and Buchan, 1998 MEGUMA ZONE (of Nova Scotia) (0.44 Ga) VOLCANIC ROCKS: White Rock Fm (0.44 Ga) INTRUSION: Brenton monzogranite (0.44 Ga) REF.: MacDonald et al., 2002; Keppie and Krogh, 2000 OVERSTEP SEQUENCE OF NEWFOUNDLAND (0.43-0.42 Ga) VOLCANIC ROCKS: bimodal volc. such as King George IV (0.43 Ga); Springdale (0.42 Ga), and Botwood groups; and mainly felsic volc. such as Sops Arm and La Poile groups INTRUSION: Taylor Brook (0.43 Ga); Main Gut (0.43 Ga) REF.: Chandler et al., 1987; Heaman et al., 2002 SETTING:? 24 0.36-0.32 Ga 24a Magdalen (Maritimes) INTRUSIONS: magmatic underplate Basin underlying entire Magdalen (Maritimes) (0.36-0.32 Ga) Basin, interpreted from gravity; (Maritimes) Wentworth and Wyvern gabbros VOLCANIC ROCKS: Cape an Diable; Fountain Lake (mafic to felsic) DYKES: widespread REF.: Pe-Piper and Piper, 1998; Murphy et al., 1999 SETTING: Plume 25 0.27-0.20 Ga (Cordillera) 25a Cache Creek VOLCANIC ROCKS: Late Triassic volcanics (Late Triassic and interpreted to represent oceanic plateau mid-Permian) (Cordillera) (Tardy et al., 2001). Overlies [~1500 km long, 50-100 km mid-Permian magmatism interpreted to wide] represent underlying Permian Crust Alternative, more complex model suggested by Struik et al. (2001) REF.: #38 in  SETTING: ?Plume (?P6) 25b Wrangellia (0.23 Ga) VOLCANIC ROCKS: Karmutsen; Nikolai (Cordillera) INTRUSIONS: Kluane [1,000,000 cu. km] SILLS: Maple Creek (0.23 Ga) REF.: #34 in ; #303-304 in  SETTING: Plume (P6) 25c Ramparts Group (0.21 Ga) SILLS AND VOLCANIC ROCKS: Ramparts Group (Alaska) (0.21 Ga) [100,000 sq. km] REF.: #306 in  SETTING: ? 26 0.20 Ga 26a ENA (Eastern North VOLCANIC ROCKS: North Mountain Basalt; America) portion of Grand Manan CAMP (Central Atlantic DYKES: ENA (0.20 Ga) Magmatic Province) (0.20 Ga) COMMENT: Rest of CAMP event is located (Atlantic Canada) along east coast of US and also in [7,000,000 sq. km for entire Europe, NW Africa and South America event] REF.: #32 in ; #307 in  SETTING: Plume (P1); Breakup (B1, forming Atlantic Ocean) 27 0.14-0.09 Ga 27a New England-Quebec (NEQ); INTRUSIONS AND PLUTONS: Monteregian Monteregian) Hills intrusions of Quebec and related (0.14-0.11 Ga) plutons of [60,000 sq. km] New England) (0.14-0.11 Ga) REF.: #323 in  SETTING: Hotspot 27b Trap (sw. Greenland) DYKES: Trap (0.14 Ga) [20,000 sq. km] REF.: #30 in ; #322 in  SETTING: ? Breakup (B2, Linked to subsequent breakup of Greenland from Laurentia to form Labrador Sea) 27c Sverdrup Basin Magmatic VOLCANIC ROCKS AND SILLS: including Province Strand Fiord pot (0.13-0.09 Ga; major (part of High Arctic Large pulse at 0.095 Ga); Alpha Ridge Igneous Province; HALIP) DYKES: Queen Elizabeth Islands (inludes (0.13-0.09 Ga) (Arctic Hazen Strait); Lightfoot River Islands) INTRUSIONS: Wootton (0.092 Ga) [550,0110 sq. km] REF.: #12 in ; #325 in ; Tarduno et al., 1998; Trettin and Parrish, 1987 COMMENT: Part of Large Igneous Province that includes Svalbard and Franz Josef Land (Maher, 2001 SETTING: Plume (P1); Breakup 28 0.07-0.05 Ga 28a Carmacks VOLCANIC ROCKS: Carmacks (0.07 Ga) (n. Cordillera) RER: #9 in  [63,000 sq. km] SETTING: Plume (? P6) 28b Crescent (0.06-0.05 Ga) VOLCANIC ROCKS: Crescent Terrane ("Coast (western margin of North Range Basalt Province") (0.06-0.05 Ga) America) REF.: #339 in ; Murphy et al., 2003 SETTING: Plume (? P6) 28c North Atlantic Igneous VOLCANIC ROCKS: Cape Dyer; West Province (NAIP) Greenland (0.06 Ga) DYKES: Cape Searle; West Greenland (Baffin Island, w. Greenland) RER: #334 and 335 in ; #5 in  [1,300,000 sq. km for entire COMMENT: Part of Noah Atlantic Igneous NAIP event] Province of Greenland, United Kingdom (0.062-0.052 Ga), and linked to present-day Iceland hotspot SETTING: Plume Breakup (Europe from Greenland) 29 0.025-0.015 Ga 29a Behm Canal (Tertiary DYKES: Behm Canal (0.023-005 Ga) 'Lamprophyre' Province) REF.: #348 in  (ca. 0.023-0.005 Ga) COMMENT: alkalic lamprophyres (c. British Columbia) SETTING: Hotspot (H1) [25,000 sq. km] 29b Columbia River Basalt VOLCANIC ROCKS, DYKES AND SILLS: Group Columbia River Basalt Group (CRBG) (mainly 0.017-0.0150 Ga) REF.: #1 in  (nw. US) SETTING: Plume (P1, P7) [165,000 sq. km] 29c Chilcotin (Neogene- VOLCANIC ROCKS: Chilcotin Group basalts; Paleogene; mainly Miocene) Anahim volcanic belt; Cheslatta Lake (c. and sc. British Columbia) suite; Masset Fm [25,000 sq. km] REF.: Anderson et al., 2001 COMMENT: Nearby to and potentially linked to Columbia River Basalt Group SETTING: Hotspot (H1) Back-arc (partial melting) Table 2 Archean greenstone belts in Canada interpreted to have a plume origin (i.e. tholeiitic sequences containing komatiites and/ or those interpreted as oceanic plateaus). Details and full referencing on most events is available in compilations  (=Ernst and Buchan 2001) and  (=Buchan and Ernst 2004), and Tomlinson and Condie (2001), or in the additional cited references. "REF.:" = key reference(s). SETTING codes are explained in Table 3. Event name Magmatic components (Age) (Age) (Location) A1 3.11-2.98 Ga A1a Hunt River GREENSTONE BELTS: Hunt River (3.11 Ga) (3.11 Ga) REF.: James et al., 2002 (Hopedale block, North COMMENT: Includes komatiites Atlantic Craton) SETTING: ?Plume (P4) A1b Florence Lake GREENSTONE BELTS: Florence Lake (2.99-2.98 Ga) (2.99-2.98 Ga) (Hopedale block, North REF.: James et al., 2002 Atlantic Craton) COMMENT: Includes komatiites SETTING: ?Plume (P4) A1c North Caribou GREENSTONE BELTS: Balmer Assemblage (Red (2.99 Ga) Lake greenstone belt) (2.99 Ga) (n. Caribou Terrane, nw. REF.: #256 in ; Tomlinson et al., Superior Prov.) 1998; Hollings et al., 1999 "plume related rifting" COMMENT: Includes komatiites SETTING: ?Plume (P4) A2 2.93-2.92 Ga A2a Western Superior GREENSTONE BELTS: Steep Rock; Finlayson; (2.93 Gal North Rim Unit of McGruer Assemblage (Wabigoon subprov., w. (2.93 Ga) Lumby Lake 2963-2898 Ma, ? Superior Prov.) Heaven Lake [U 2954 Ma] REF.: #252 in  COMMENT: Includes komatiites. Rifting or impingement of plume in subduction setting (Hollings et al. 1999) SETTING: ?Plume (P4) Back-arc (A2) A3 2.86 Ga A3a Pickle Crow GREENSTONE BELTS: Pickle Crow Assemblage (2.86 Ga) (~2.86 Ga) (Uchi subprov., nw. Superior REF.: #244 in  Prov.) COMMENT: Includes komatiites SETTING: ?Plume (P4) A4 2.79-2.78 Ga A4a Vizien GREENSTONE BELTS: Vizien (2.79 Ga) (2.79 Ga) REF.: #236 in  (Minto Block, ne. Superior COMMENT: Includes komatiites Prov.) SETTING: ?Plume (P4, P6) A4b Faribault-Thury GREENSTONE BELTS: greenstone belt (ca. 2.88-2.71 Ga) remnants in Faribault-Thury Complex (Minto Block, ne. Superior (~2.88-2.71 Ga) Prov.) REF.: Maurice et al., 2003 SETTING: ?Plume (P4) A4c Fourbay GREENSTONE BELTS: Fourbay Sequence in (2.78 Ga) Savant Lake and Sturgeon Lake (2.78 Ga) (Wabigoon subprov, w. REF.: Sanborn-Barrie and Skulski, 1999 Superior Prov.) COMMENT: Possible oceanic plateau setting SETTING: ?Plume (P6) A5 2.75-2.70 Ga A5a Prince Albert-Woodburn GREENSTONE BELTS: (~2.73 Ga): Prince (2.73 Ga) Albert Group; Woodburn Group; Mary River (Rae Prov.) Group, ?Murmac Bay Group [>1000 km. long belt] REF.: #220 in ; Schau, 1997; Aspler et al., 1999; Zaleski et al., 2001; Hartlaub et al., 2002; Skulski et al., 003a,b. COMMENT: Includes komatiites SETTING: ?Plume (P4) ?Breakup Rae Craton A5b Kam VOLCANIC ROCKS and DYKES: Kam Group and (2.73-2.70 Ga) early dykes (2.73-2.70 Ga). (Slave Prov.) REF.: #227 in  COMMENT: Widespread tholeiitic cover sequence SETTING: ?Plume (?P3) A5c Abitibi GREENSTONE BELTS: includes komatiites: (2.75-2.70 Ga) Pacaud (2750-2735 Ma); Stoughton- (Abitibi belt, Superior Roquemaure (2725-2720 Ma); Kidd-Munro Prov.) (2718-2710 Ma); Tisdale (2710-2703 Ma) REF.: #224 in ; Ayer et al., 2002; Sproule et al., 2002 COMMENT: Includes komatiites SETTING: ?Plume (P4); Back-arc (A2) A5d Wawa GREENSTONE BELTS: Schreiber-Hemlo-White (2.75-2.74 Ga) River-Dayohessarah (2.75-2.74 Ga) (Wawa belt, Superior Prov.) REF.: #230 in [1) COMMENT: Includes komatiites SETTING: ?Plume (P4) Table 3 Selected criteria for interpreting origin and setting of LIPs and smaller intraplate mafic events. Label Criteria MANTLE PLUME LINK P1 Radiating dyke swarm P2 Linear dyke swarm (or belt of mafic magmatism) perpendicular to cratonic margin (failed-arm type of Fahrig, 1987; could also be called aulacogen-type). P3 Large event, distal from cratonic boundary P4 Presence of high-Mg rocks, e.g. komatiites in Archean greenstone belts P5 Geochemistry: OIB or FOZO signature P6 Accreted oceanic plateaus P7 Link to present-day hotspot BREAKUP LINK B1 Radiating swarm or failed-arm type swarm (Fahrig, 1987) with convergence point near cratonic margin of similar age B2 Linear dyke swarm, parallel to and nearby cratonic margin of similar age. This is termed passive margin type swarm by Fahrig (1987) B3 LIP situated nearby cratonic margin of similar age ARC LINK A1 Location in a back-arc setting relative to concurrent orogenic activity. However, this does not necessarily require back-arc extension processes. (See Note 1, below) A2 Coexisting with arc magmatism HOTSPOT (OF UNSPECIFIED ORIGIN) H1 Small (sub-LIP scale) region of anomalous intraplate mafic volcanism Note 1: The Keweenawan rift activity is arguably in a back-arc setting with respect to the Grenville orogen, yet it is generally viewed that the Keweenawan magmatism is plume-related (see discussion in text).
John Morgan John Morgan is a common name, especially in Wales, UK. Well-known people with this name include: Per profession
A geological survey of Canada.
[FIGURE 2 OMITTED]
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Anderson, D.L., 2001, Top-down tectonics tectonics
Scientific study of the deformation of the rocks that make up the Earth's crust and the forces that produce such deformation. It deals with the folding and faulting associated with mountain building; the large-scale, gradual, upward and downward movements of the : Science, v. 293, p. 2016-2018.
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Silicate mineral, zirconium silicate, ZrSiO4, the principal source of zirconium. Zircon is widespread as an accessory mineral in acid igneous rocks; it also occurs in metamorphic rocks and, fairly often, in detrital deposits. and monazite monazite (mŏn`əzīt), yellow to reddish-brown natural phosphate of the rare earths, mainly the cerium and lanthanum metals, usually with some thorium. Yttrium, calcium, iron, and silica are frequently present. geochronology of tonalitic gneiss from Close Lake, Wollaston-Mudjatik Transition Zone, northern Saskatchewan [abstract], Vancouver 2003 (GAC-MAC-SEG meeting), abstract no. 545 CD-ROM CD-ROM: see compact disc.
in full compact disc read-only memory
Type of computer storage medium that is read optically (e.g., by a laser). .
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tr.v. tran·sect·ed, tran·sect·ing, tran·sects
To divide by cutting transversely.
[trans- + -sect. across the Snowbird snowbird: see junco. tectonic zone, western Angikuni Lake, Northwest Territories Northwest Territories, territory (2001 pop. 37,360), 532,643 sq mi (1,379,028 sq km), NW Canada. The Northwest Territories lie W of Nunavut, N of lat. 60°N, and E of Yukon. (Nunavut): in Current Research, Part C, Geological Survey of Canada Paper 1999-C, p. 107-118.
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Any of several medium- or coarse-grained rocks that consist primarily of plagioclase feldspar and pyroxene. Gabbros are found widely on the Earth and on the Moon. sills (2.11 Ga), Hurwitz Basin, Nunavut, Canada: Precambrian Research, v. 117, p. 269-294.
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The process by which the body uses minerals to build bone structure.
Mentioned in: Rickets
n the bioprecipitation of an inorganic substance. of Proterozoic Volcanic Suites: Geological Society Special Publication (London), no. 33, p. 113-131.
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natural resource, natural resources - resources (actual and potential) supplied by nature Report 99-4, p. 1-17.
Bell, R., 1870, Report of Mr. Robert Bell Robert Bell may refer to:
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Dike: see Horae.
dike, in technology
dike, in technology: see levee.
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Any one of the sciences, such as geology or geochemistry, that deals with the earth.
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n. pl. min·er·al·o·gies
1. The study of minerals, including their distribution, identification, and properties.
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Of or relating to a crust, especially that of the earth or the moon.
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The process of mountain formation, especially by a folding and faulting of the earth's crust.
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The branch of petrology that deals with the origin of rocks, especially igneous rocks.
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A beer mug.
[German, from Middle High German sdel, from Latin situla, bucket.]
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named after North America.
North American blastomycosis
see North American blastomycosis.
North American cattle tick
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Hulbert, L., 2002, Magmatic platinum group The platinum group (alternatively, the platinum group metals or platinum metals) is a collective name sometimes used for six metallic elements clustered together in the periodic table. element environments in Canada: present and future exploration target areas: Geological Association of Canada Robinson Lecture 2002, MP#2 [CD-ROM]
Hulbert, L., Stern, R., Kyser, T.K., Pearson, J., Lesher, M. and Grinenko, L., 1994, The Winnipegosis komatiite Komatiites are ultramafic mantle-derived volcanic rocks. They have low SiO2, low K2O, low Al2O3, and high to extremely high MgO.
Komatiites were named for their type locality along the Komati River in South Africa. belt Central Manitoba. Manitoba Energy and Mines, Manitoba: Mining Minerals and Petroleum Convention 94. Program with Abstracts, p. 21.
Hulbert, L.J., Hamilton, M.A., Horan, M.J. and Scoates, R.F.J., 2004, U-Pb zircon and Re-Os isotope isotope (ī`sətōp), in chemistry and physics, one of two or more atoms having the same atomic number but differing in atomic weight and mass number. The concept of isotope was introduced by F. geochronology of mineralized min·er·al·ize
v. min·er·al·ized, min·er·al·iz·ing, min·er·al·iz·es
1. To convert to a mineral substance; petrify.
2. To transform a metal into a mineral by oxidation.
3. ultramafic intrusions and associated nickel ores from the Thompson Nickel Belt, Manitoba, Canada: Economic Geology economic geology
Scientific discipline concerned with the distribution of mineral deposits, the economic considerations involved in their recovery, and assessment of the reserves available. (in press).
Irving, E., Baker, J., Hamilton, M. and Wynne, P.J., 2004, Early Paleoproterozoic geomagnetic field geomagnetic field
Magnetic field associated with the Earth. It is essentially dipolar (i.e., it has two poles, the northern and southern magnetic poles) on the Earth's surface. Away from the surface, the field becomes distorted. in western Laurentia: implications for paleolatitude, local rotations and stratigraphy: Precambrian Research, v. 129, p. 251-270.
Isley, A. E. and Abbott, D. H., 2002, Implications for the temporal distribution of high-Mg magmas for mantle plume volcanism through time: The Journal of Geology, v. 110, p. 141-158.
Jackson, G.D. and Taylor, F.C., 1972, Correlation of major Aphebian rock units in the northeastern Canadian Shield: Canadian Journal of Earth Sciences, v. 9, p. 1650-1669.
James, D.T., Kamo, S. and Krogh, T., 2002, Evolution of 3.1 and 3.0 Ga volcanic belts A volcanic belt is a large volcanic region. Other terms are used for smaller areas of activity; in shrinking size there are volcanic belts, clusters, chains and fields. and a new thermotectonic model for the Hopedale Block, North Atlantic craton (Canada): Canadian Journal of Earth Sciences, v. 39, p. 687-710.
Johnston, S.T., Wynne, P.J., Francis, D., Hart, C.J.R., Enkin, R.J. and Engebretson, D.C., 1996, Yellowstone in Yukon: the Late Cretaceous Late Cretaceous (100mya - 65mya) refers to the second half of the Cretaceous Period, named after the famous white chalk cliffs of southern England, which date from this time. Rocks deposited during the Late Cretaceous Period are referred to as the Upper Cretaceous Series. Carmacks Group: Geology, v. 24, p. 997-1000.
Ketchum, J.W.F., Jackson, S.E., Culshaw, N.G. and Barr, S.M., 2001, Depositional and tectonic setting of the Paleoproterozoic Lower Aillik Group, Makkovik, Province, Canada: evolution of a passive margin-foredeep sequence based on petrochemistry pet·ro·chem·is·try
1. The chemistry of petroleum and its derivatives.
2. The branch of geochemistry that deals with the chemical composition of rocks. and U-Pb (TIMS TIMS Thermal Ionization Mass Spectrometry
TIMS The Institute of Management Sciences
TIMS Thermal Infrared Multispectral Scanner
TIMS Transportation Information Management System
TIMS The International Molinological Society
TIMS Tuberculosis Information Management System and LAM-ICP-MS) geochronology: Precambrian Research, v.105, p. 331-356.
Keppie, J.D. and Dostal, J., 1994, Late Silurian--Early Devonian transpressional rift origin of the Quebec Reentrant re·en·trant also re-en·trant
Reentering; pointing inward.
A reentrant angle or part.
Adj. 1. reentrant - (of angles) pointing inward; "a polygon with re-entrant angles"
re-entrant , northern Appalachians: constraints from geochemistry of volcanic rocks: Tectonics, v. 13, p. 11831-189.
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Marillier, F. and Verhoef, J., 1989, Crustal thickness under the Gulf of St. Lawrence Noun 1. Gulf of St. Lawrence - an arm of the northwest Atlantic Ocean off the southeastern coast of Canada
Gulf of Saint Lawrence
Atlantic, Atlantic Ocean - the 2nd largest ocean; separates North and South America on the west from Europe and Africa on the east , northern Appalachians, from gravity and deep seismic data: Canadian Journal of Earth Sciences, v. 26, p. 1517-1532.
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n. pl. min·er·al·o·gies
1. The study of minerals, including their distribution, identification, and properties.
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Mountain-building event that affected the northern portion of the Appalachian Geosyncline from present-day New York to Newfoundland during the Devonian period. The orogeny was most intense in northern New England. in the northern Appalachians: A Laramide-style plume-modified orogeny orogeny
Mountain-building event, generally one that occurs in a geosyncline. Orogeny tends to occur during a relatively short geologic time frame. It is usually accompanied by folding and faulting of strata and by the deposition of sediments in areas adjacent to the orogenic ?: Geology, v. 27, p. 653-656.
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linked metal, curved bars that fit around the horse collar and serve as the attachment for the trace chains and traces. , W.E., McHone, J.G., Renne, P.R., and Ruppel, C. (eds.), The Central Atlantic Magmatic Povince: insights from fragments of Pangea: American Geophysical Union, Geophysical Monograph, v. 136, p. 255-267.
Park, J.K., Buchan, K.L., and Hadan, S.S., 1995, A proposed giant radiating dyke swarm fragmented by the separation of Laurentia attd Australia--based on paleomagnetism of circa circa
prep. Abbr. ca
In approximately; about. 780 Ma mafic intrusions in western North America: Earth and Planetary Science Letters, v. 132, p. 129-139.
Pe-Piper, G. and Piper D.J.W., 1998, Geochemical evolution of Devonian-Carboniferous igneous rocks igneous rock: see rock.
Any of various crystalline or glassy, noncrystalline rocks formed by the cooling and solidification of molten earth material (magma). of the Magdalen basin, eastern Canada: Pb- and Nd-isotope evidence for mantle and lower crustal sources: Canadian Journal of Earth Sciences, v. 35, p. 201-221.
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Water that makes up the oceans and seas. Seawater is a complex mixture of 96.5% water, 2.5% salts, and small amounts of other substances. Much of the world's magnesium is recovered from seawater, as are large quantities of bromine. composition through the past 3500 million years [abstract]: in Kerr, A., England, R. and Wignall, P. (convenors), Mantle plumes: Physical processes, chemical signatures, biological effects. Multidisciplinary meeting held at Cardiff University Cardiff University (Welsh: Prifysgol Caerdydd) is a leading university located in the Cathays Park area of Cardiff, Wales. It received its Royal charter in 1883 and is a member of the Russell Group of Universities. It has an annual turnover of £315 million. and the National Museum and Gallery, Cardiff, Wales Wales, Welsh Cymru, western peninsula and political division (principality) of Great Britain (1991 pop. 2,798,200), 8,016 sq mi (20,761 sq km), west of England; politically united with England since 1536. The capital is Cardiff. , 11-12 September 2003.
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Assessment of relationships between two or among more variables over periods of time. of Large Igneous Provinces: 3500 Ma to Present: The Journal of Geology, v. 112, p. 1-22.
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Rainbird, R. and Ernst, R.E., 2001, The sedimentary record of mantle-plume uplift, in Ernst, R.E. and Buchan, K.L. (eds.), Mantle Plumes: Their Identification Through Time: Geological Society of America, Special Paper 352, Boulder, CO., p. 227-245.
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Variant of blacky. and Co. Publishers Ltd., Glasgow, United Kingdom, 285 p.
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NTS National Trust for Scotland
NTS Nevada Test Site
NTS NT Server (Microsoft Windows)
nts Not the Same
NTS National Traffic System (amateur radio) 14D/9 and 16), in Current Research, Newfoundland Department of Mines and Energy, Geological Survey, Report 04-1, p. 235-258.
Sanborn-Barrie, M., and Skulski, T., 1999, Tectonic assembly of continental margin and oceanic terranes at 2.7 Ga in the Savant sa·vant
1. A learned person; a scholar.
2. An idiot savant.
[French, learned, savant, from Old French, present participle of savoir, to know Lake--Sturgeon Lake greenstone belt, Ontario: in Current Research Part C; Geological Survey of Canada, Paper 1999-C, p. 209-220.
Schau, M., 1997, Geology of the Archean Prince Albert Group in the Richards Bay Richards Bay is one of South Africa's largest harbours (). It is situated on a 30 square kilometre lagoon of the Mhlatuze River, (forceful), on the northern coast of KwaZulu-Natal. area, northeastern Melville Peninsula Melville Peninsula, 24,156 sq mi (62,564 sq km), c.250 mi (400 km) long and from 70 to 135 mi (113–217 km) wide, Nunavut, Canada, between the Gulf of Bothnia and Foxe Basin, and separated from Baffin Island to the N by the Fury and Hecla Strait; it is joined to , District of Franklin The District of Franklin was a former regional administrative district of Canada's Northwest Territories. The district consisted of the Canadian high Arctic Islands, notably Ellesmere Island, Baffin Island, and Victoria Island. , Northwest Territories: Geological Survey of Canada, Bulletin 385, 44 p.
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Schwab, D.L., Thorkelson, D.J., Mortensen, J.K., Creaser crease
1. A line made by pressing, folding, or wrinkling.
a. A rectangular area marked off in front of the goal in hockey and lacrosse.
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v. in·trud·ed, in·trud·ing, in·trudes
1. To put or force in inappropriately, especially without invitation, fitness, or permission: by OIB-like magmatism: Ofioliti, v. 24, p. 199-215.
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Having the edges overlapping in a regular arrangement like roof tiles or the scales of a fish.
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One of two or more atoms having the same atomic number but different mass numbers.
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1. Place of origin; derivation.
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Van Wagoner The Van Wagoner was an American automobile manufactured between 1899 and 1900. Advertised as being "built on a simple plan that does away with several levers and push buttons", the car was built in Syracuse, New York, and could supposedly be "controlled with one hand". , N., Leybourne, M.I., Dadd, K.A. and Huskins, M.L.A., 2001, The Silurian(?) Passamaquoddy Bay Passamaquoddy Bay (păsəməkwŏd`ē), inlet of the Bay of Fundy, between Maine and New Brunswick, at the mouth of the St. Croix River. Most of it (including Campobello island) is within Canada's border. mafic dyke swarm, New Brunswick: petrogenesis and tectonic implications: Canadian Journal of Earth Sciences, v. 38, p. 1565-1578.
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Waldron, J.W.F. and van Staal, C.R., 2001, Taconic orogeny Taconic Orogeny
Mountain-building event that affected the Appalachian Geosyncline along the eastern coast of the U.S. Evidence for the orogeny is most pronounced in the northern Appalachian Mountains, but its effects can be noted as far away as Tennessee and Georgia. and the accretion of the Dashwoods block: a peri-Laurentian microcontinent in the Iapetus Ocean: Geology v. 29, p. 811-814.
White, R.S. and McKenzie, D.P., 1989, Magmatism at rift zones rift zone
A large area of the earth in which plates of the earth's crust are moving away from each other, forming an extensive system of fractures and faults. : the generation of volcanic continental margins and flood basalts: Journal of Geophysical Research Journal of Geophysical Research is a publication of the American Geophysical Union. JGR was formerly titled Terrestrial Magnetism from its founding by the AGU's president Louis A. , v. 94, p. 7685-7729.
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Wyman DA., 1999, A 2.7 Ga depleted de·plete
tr.v. de·plet·ed, de·plet·ing, de·pletes
To decrease the fullness of; use up or empty out.
[Latin d tholeiite suite: evidence of plume-arc interaction in the Abiribi belt, Canada: Precambrian Research, v. 97, p. 27-42
Zaleski, E., Davis, W.J. and Sandeman, H.A., 2001, Continental extension, mantle magmas and basement cover relationships, in Cassidy, K.F., Dumphy, J.M. and Van Kranendonk, M.J. eds., extended abstracts, 4th International Archean Symposium 2001, Australian Geological Survey Organization--Geoscience Australia, Record 2001/37, p.374-376.
Zwanzig, H.V., Bailes, A.H. and Bohm, Ch.O., 2001, Josland Lake sills: U-Pb age and tectonostratigraphic implications (parts of NTS 63K and 63N): in Report of Activities 2001, Manitoba Industry, Trade and Mines, Manitoba Geological Survey, p. 28-32.
R.E. Ernst and K.L. Buchan
Geological Survey of Canada
601 Booth Street
Ottawa, Ontario K1A OE8
Geological Survey of Canada publication no. 2004026
Accepted as revised 30 June 2004