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Chair: David Ufnar, University of Southern Mississippi

Vice-chair: James Starnes, MS Department of Environmental Quality

FRIDAY MORNING

Hunter Henry Brunson

9:00 HYDROGEOLOGIC ASSESSMENT OF A PROPOSED RESERVOIR SITE, SMITH COUNTY, MISSISSIPPI Smith County is a county located in the U.S. state of Mississippi. As of 2000, the population is 16,182. Its county seat is Raleigh6. Smith County is named for Major David Smith. Geography
According to the U.S.
 

Jason A. McIlwain*, Darrel W. Schmitz, and James H. May, Mississippi State University Mississippi State University, at Mississippi State, near Starkville; land-grant and state supported; coeducational; chartered 1878 as an agricultural and mechanical college, opened 1880. From 1932 to 1958 it was known as Mississippi State College. , Mississippi State, MS 39762

The Oakohay Creek watershed in Smith County, Mississippi, is a proposed site for the development of a reservoir intended to boost the county's economy. The site is being assessed for suitability based on the hydrogeology hy·dro·ge·ol·o·gy  
n.
The branch of geology that deals with the occurrence, distribution, and effect of ground water.



hy
 of the area. There are three components to the site assessment. The first component involves examining the hydrologic characteristics of the drainage basin. Stream discharge is monitored at eight locations along Oakohay Creek and its tributaries. Stage-discharge hydrographs are constructed based on the obtained data. The second component of the study is based on studying the site's geology. The geology is being studied through field reconnaissance, surface mapping, and examination of geophysical well log data from the MDEQ MDEQ Michigan Department of Environmental Quality
MDEQ Mississippi Department of Environmental Quality
MDEQ Montana Department of Environmental Quality
MDEQ Massachusetts Department of Environmental Quality
 as well as drillers' logs from seismic exploration. Cross-sections have been constructed based on the available data. Surface mapping of the Glendon/Marianna formations (limestones and marls) of the Vicksburg Group is being conducted. Outcrops of the Glendon/Marianna formations are present along Oakohay Creek near the proposed dam site. Potential dissolution of the Glendon/Marianna formations could cause leakage and instability of the dam. Currently, drilling, along with coring of the Glendon/Marianna formations, is taking place that will provide information for the project. The third component of the study involves the assessment of water quality within the basin. Samples are taken for analysis by the Mississippi State Chemical Laboratory.

9:20 DETERMINING THE POTENTIAL FOR DIRECT RECHARGE IN THE MISSISSIPPI RIVER ALLUVIAL AQUIFER USING SOIL CORE ANALYSES, WASHINGTON CO., MS

Claire E. Rose (1), Jeannie Bryson (2), and Stan Galicki (1), (1) Millsaps College, Jackson, MS 39210 and (2) USGS USGS United States Geological Survey (US Department of the Interior) , Pearl, MS 39208

The potential for water and chemical transport to the Mississippi River Alluvial Aquifer in the Bogue Phalia watershed via vertical recharge was investigated by determining the hydraulic conductivity of sediment in the upper 6 m. Three methods were used; direct measurement of core segments using a falling head permeameter, bulk density and sediment composition data in conjunction with the Rosetta Stone software, and the Hazen method using particle size distribution The particle size distribution[1] ("PSD") of a powder, or granular material, or particles dispersed in fluid, is a list of values or a mathematical function that defines the relative amounts of particles present, sorted according to size.  data. The upper 3 m of topostratum consists of a clay loam with vertical hydraulic conductivity values ranging from [10.sup.-5] to as low as [10.sup.-7] cm/s. The interval from 3 m to approximately 6 m was a sandy loam with hydraulic conductivity values ranging from [10.sup.-3] to [10.sup.-4] cm/s. The sediment composition, bulk density values, and vertical hydraulic conductivity values in the upper 3 m indicate that a relatively homogenous blanket of lower permeability clay loam persists in the area and that that the potential for vertical recharge is low. Appreciable lateral recharge from the nearby Bogue Phalia River is likely as the river incises through the clay loam to the higher conductivity fine, sandy loam interval.

9:40 NON-POINT SOURCE CONTAMINATION OF WETLAND SEDIMENT, LEFLUER'S BLUFF STATE PARK, JACKSON, MS

Becky D. McDole and Stan Galicki, Millsaps College, Jackson, MS 39210

Runoff and overland flow from the 40 hectare Lefluer's Bluff Golf Course contribute to Eubanks Creek and the Pearl River within the Jackson Watershed. The area of study is situated in a cypress-tupelo alluvial swamp adjacent to the golf course. Two sediment cores were dated using [210.sup.Pb] and [137.sup.Cs]. One core was immediately adjacent to the golf course drainage; the second was at a remote location in the floodplain floodplain, level land along the course of a river formed by the deposition of sediment during periodic floods. Floodplains contain such features as levees, backswamps, delta plains, and oxbow lakes. . Carbon, nitrogen, and phosphorus concentrations were determined at regular intervals from the cores. Based on a calculated sediment accumulation rate of approximately 2 cm/yr, element concentration profiles were constructed for each core. Phosphorus and N concentrations in the core adjacent to the golf course are typically greater overall, but also display a notable increase in concentration from horizons that post date golf course construction; nutrient concentration increases in the remote core are more gradual. Correlations between nutrient concentrations in each sample also reflect a difference; values in the remote core typically maintain higher correlation coefficients which range from 0.77 to 0.93, while correlation coefficients from the remote core only range from 0.17 to 0.54. A similar relationship is also observed for pre and post construction intervals in the core most influenced by runoff. The difference observed between cores is attributed to the increased availability of N and P in stormwater in the area most heavily influenced by runoff.

10:00 THE GEOLOGY AND HYDROLOGY OF A PROPOSED IMPOUNDMENT An action taken by the president in which he or she proposes not to spend all or part of a sum of money appropriated by Congress.

The current rules and procedures for impoundment were created by the Congressional Budget and Impoundment Control Act of 1974 (2 U.S.C.A.
 OF THE UPPER SAND CREEK, CHOCTAW COUNTY, MISSISSIPPI Choctaw County is a county located in the U.S. state of Mississippi. As of 2000, the population is 9,758. Its county seat is Ackerman6. Choctaw County is named after the Choctaw Native Americans. History
Choctaw County was formed in 1833.
 

Jonathan R McMillin*, Darrel W. Schmitz, and James H. May, Mississippi State University, Mississippi State, MS 39762

The Sand Creek watershed, Choctaw County, Mississippi, constitutes a proposed site for a recreational and water management reservoir. Prior to the development of the site, the geology and hydrogeology of the watershed must be investigated to determine suitability for impoundment. The proposed site is located within the Wilcox Group, a sequence of interbedded sands, silts, clays and lignites of Eocene age. Geological cross sections derived from geophysical logs and field exploration provides information regarding facies distributions within the proposed site area. Discharge characteristics of both perennial and ephemeral streams at seven locations provide data concerning surface runoff that can then be related to infiltration into the Lower Wilcox Aquifer. These measurements will aid in determining if there is sufficient water flow for impoundment. All data collected and the characteristics of the reservoir are mapped using ArcGIS 9.1 software. Analysis of the study area suggests that the proposed site is suitable for the location of a reservoir. Mitigation of permeable sands should be accomplished by the construction of a levee at the mouth of the reservoir.

10:20 Break

10:40 THE TOMBIGBEE RIVER TERRACE SYSTEM E.

Russell and D. Schmitz*, Mississippi State University, Mississippi State, MS 39762

The Tombigbee River in Mississippi has three to four well developed and one poorly preserved terrace deposits. Near Amory the relatively flat surface of the modern alluvium al·lu·vi·um  
n. pl. al·lu·vi·ums or al·lu·vi·a
Sediment deposited by flowing water, as in a riverbed, flood plain, or delta. Also called alluvion.
 ranges from 190 to 200 feet MSL. The terrace surfaces are progressively more dissected with age and the average elevation of the basal gravels in the first terrace deposit is ~230 feet MSL, the second at ~260 feet MSL, third at ~290 feet MSL, and the fourth at ~320 feet MSL. The uppermost fifth terrace deposit outcrop has no topographic expression. Downstream the base of the terrace deposits decrease in elevation. Typically, the Tombigbee River alluvium is about 30 feet (9 meters) thick as are the first four terrace deposits. The basal horizon consists of iron stained, poorly sorted chert chert: see flint.  gravel with small rounded pebbles of quartzite quartzite, usually metamorphic rock composed of firmly cemented quartz grains. Most often it is white, light gray, yellowish, or light brown, but is sometimes colored blue, green, purple, or black by included minerals.  and fine- to coarse-grained quartz sands that grade upward into quartz sand that, in turn, grades upward into yellowish-orange, sandy silts and clays, a typical meandering stream deposit. The fifth terrace deposit consists locally of remnants of quartz sand with small, well-rounded, chert pebbles, and rare quartzite pebbles in the basal beds. Like the alluvium, the gravels in the terrace deposits diminish down stream away from the source beds, the Gordo Gordo, the Spanish word for fat, may refer to:
  • Gordo (space monkey), the first monkey to travel beyond Earth's orbit
  • Gordo, Alabama, Alabama, USA
  • Gordo (comic strip) a comic strip created by Gus Arriola
 Formation. The terraces are best developed where the chert gravels defend the terraces below the confluence of Bull Mountain Creek and Buttahatchie River.

11:00 PRE-POST KATRINA BACTERIAL POLLUTION OF THE MISSISSIPPI SOUND

David F. Ufnar, University of Southern Mississippi, Hattiesburg, MS 39406

Microbial source tracking efforts have traditionally focused on the input of fecal bacteria from sources such as storm drains, sewers, and runoff. Fecal coliform coliform /col·i·form/ (kol´i-form) pertaining to fermentative gram-negative enteric bacilli, sometimes restricted to those fermenting lactose, e.g., Escherichia, Klebsiella, or Enterobacter.  levels in the Mississippi Sound have been analyzed and compared to physical factors in an attempt to characterize possible non-point sources of pollution. Results from this study show that a primary factor in elevated levels of fecal coliforms is barometric pressure and the resulting changes in wind direction. Fecal coliform counts collected from monitoring stations along the Harrison County, Mississippi Harrison County is a county located in the U.S. state of Mississippi. It is part of the Gulfport-Biloxi, Mississippi Metropolitan Statistical Area. As of 2000, the population was 189,601. Its county seats are Biloxi and Gulfport. Harrison County is named for U.S.  coast during May-August, 2005 prior to Hurrican Katrina, 8/29/05, and following Katrina (9/24/05--present) have been compared with barometric pressure readings over that time interval. The occurrence of high fecal coliform counts can be qualitatively correlated with low barometric pressure. Statistically, there is a correlation between high barometric pressure (>1019 mb) and low bacterial counts. The low bacterial counts are most likely to occur when the winds are from a northerly direction. The passage of warm and cold fronts through the northern Gulf of Mexico Noun 1. Gulf of Mexico - an arm of the Atlantic to the south of the United States and to the east of Mexico
Golfo de Mexico

Atlantic, Atlantic Ocean - the 2nd largest ocean; separates North and South America on the west from Europe and Africa on the east
 cause excursions in barometric pressure, and numerous 90[degrees]-180[degrees] shifts in wind directions over a period of 6-8 days. Commonly, a rise in fecal coliform counts is observed at coastal monitoring stations after an abrupt change in barometric pressure, and a shift in wind directions and wind speeds. When these trends of increased fecal coliform levels occur prior to rainfall, it is inferred that the sediment may be a source of the fecal coliform bacteria observed in the water column. The changes in wind direction and speed may induce more energetic conditions at the shoreline (e.g. increased wave heights, and increased nearshore current velocities).

11:20 Poster

LOESS loess (lĕs, lō`əs, Ger. lös), unstratified soil deposit of varying thickness, usually yellowish and composed of fine-grained angular mineral particles mixed with clay.  CAVES OF VICKSBURG

Amber L. Bufk in and Danny Harrelson*, U.S. Army Engineer Research and Development Center The Engineer Research and Development Center or ERDC is a United States government funded military base located at Vicksburg, Mississippi. The base was set up after the 1927 flood disaster of the Mississippi River. The base is staffed by the U.S. Army Corps of Engineers.  (ERDC ERDC Engineer Research and Development Center
ERDC Economic Research and Development Center
ERDC Eleanor Roosevelt Democratic Club (Orange County, California)
ERDC Exploratory Research and Development Center
ERDC Extended Response Data Call
), Vicksburg, MS 39180

The loess caves of Vicksburg were made famous during the Siege of Vicksburg in the American Civil War American Civil War
 or Civil War or War Between the States

(1861–65) Conflict between the U.S. federal government and 11 Southern states that fought to secede from the Union.
. They were not true caves in the geologic sense because none were naturally formed subterranean openings. The caves uniqueness lies in the fact that they were made in loess materials as shelters to avoid artillery bombardments during the Vicksburg Campaign. Because of loess's ability to hold a vertical cut, the material made easily excavated bombardment shelters with walls that could stand for many years without slumping. However, a few of the caves did become unstable during constant bombardment and it was reported some collapsed and buried alive some unfortunate souls. Loughborough, 1990, describes in details life in these caves and recounts how many persons tried to live their lives "normally" in a loess cave during the siege operations. Contemporary accounts reported the caves to be large enough for several humans to enter and some even large enough to accommodate 200 people. Because of the ability to hold stable vertical slopes, loess caves are still a popular form of dwelling that is still in use today in many countries (e.g. China) for human habitation.

FRIDAY AFTERNOON

Hunter Henry Brunson

1:30 HOUSING THE STATE GEOLOGICAL SURVEY

Michael B. E. Bograd, Mississippi Office of Geology, Jackson, MS 39289

The Mississippi Geological Survey, now the Office of Geology, Mississippi Department of Environmental Quality (MDEQ), has been housed in several locations since 1850. Some moves followed changes in enabling legislation. The first location was a prominent second-floor room in the Lyceum at the University of Mississippi The University of Mississippi, also known as Ole Miss, is a public, coeducational research university located in Oxford, Mississippi. Founded in 1848, the school is composed of the main campus in Oxford and three branch campuses located in Booneville, Tupelo, and Southaven.  (UM) where the State Geologist was professor of geology. State Geologist Lewis Harper moved the Survey to the State Penitentiary in Jackson and had a prisoner on staff. Dr. Eugene Hilgard, who is credited with convincing Union troops not to burn the UM campus, had offices at UM and in the State Capitol. After a hiatus during Reconstruction, the Survey was reestablished in 1906 with State Geologist Albert Crider at Biloxi, and his staff Calvin Brown at UM and William Logan at Mississippi A & M College. From 1909 to 1924 the Survey was in the New and then Old Capitol at Jackson. From 1924 to 1963 the Survey was housed at UM's Old Library Building, the most attractive building on campus. In 1960 the Survey opened a core and sample library at 2525 North West Street in Jackson to better serve the state's oil industry; the entire agency moved to that building in 1963. Most staff moved in 1991 to the MDEQ headquarters in Southport Center at Ellis Avenue and Highway 80 in Jackson. MDEQ hopes new quarters off the flood plain of Lynch Creek will be found soon.

1:50 THE GEOLOGY OF MISSISSIPPI; A DVD DVD: see digital versatile disc.
DVD
 in full digital video disc or digital versatile disc

Type of optical disc. The DVD represents the second generation of compact-disc (CD) technology.
 PUBLICATION STATUS REPORT

David T. Dockery III, Mississippi Office of Geology, Jackson, MS 39289

The Geology of Mississippi text is an 891-page (single-spaced) WordPerfect file containing 462,606 words and over 4,000 references. A separate file contains several hundred captioned illustrations in tiff format to accompany the text. These files will be merged, with connecting links, in a DVD publication. An abridged version is planned for a color hardcopy publication. Both the DVD and hardcopy publications will contain many illustrations of historical value, depicting outcrops no longer exposed today. The book contains introductory chapters, the largest of which are on groundwater, physiographic phys·i·og·ra·phy  
n.
See physical geography.



physi·ogra·pher n.
 provinces, and ecoregions This is a list of ecoregions as compiled by the World Wildlife Fund (WWF). The WWF identifies terrestrial, freshwater, and marine ecoregions.

The terrestrial scheme divides the Earth's land surface into 8 terrestrial ecozones, containing 867 smaller ecoregions.
, followed by a systematic discussion of the state's geology from the oldest to the youngest rocks. Discussions of global time-rock units and the geologic column contain important references published in Nature and Science, as well as information on global boundary stratotypes. The discussion of Mississippi's local geology is based on personal experience, institutional knowledge, and a review of relevant literature, including a complete review of the following: all publications of the Mississippi Geological Survey (now Office of Geology), all publications of the Mississippi Mineral Resources Institute, all volumes of Gulf Coast Association of Geological Societies Transactions, and all issues of Geology and the Journal of Paleontology The Journal of Paleontology is a scientific journal covering the field of paleontology, published by The Paleontological Society. It is indexed by BIOSIS Previews, Science Citation Index, The Zoological Record and GeoRef and has an impact factor of 0.4499 [1]. . The societal impact of the state's geology is reflected in the citation of numerous newspaper articles. Significant geologic outcrops in the state are described as Mississippi Geological Survey (MGS) localities 1-166.

2:10 THE DEFINING OF CITRONELLE SURFACES IN SOUTH MISSISSIPPI AND THE SURFACE EXPRESSION OF RUTH SALT DOME

James E. Starnes* and Patricia Mason, Mississippi Office of Geology, Jackson, Mississippi 39289 and Mississippi Office of Land and Water Resources, Jackson, MS 39289

The use of the Mississippi Automated Resource Information Systems (MARIS) 10-meter Digital Elevation Model A digital map of the elevation of an area on the earth. The data are either collected by a private party or purchased from an organization such as the U.S. Geological Survey (USGS) that has already undertaken the exploration of the area.  (DEM See digital elevation model. ) allows for accurate identification and mapping of Pliocene age alluvial surfaces of the Citronelle Formation. These surfaces consist predominantly of tan to yellow silt with a minor constituent of fine sand, which is indicative of a floodplain depositional environment. The highest of these surfaces is 550 feet MSL in southwestern Simpson County and is typified at the Magee Municipal Airport in Section 3, Township 10 North, Range 18 West. The next highest, for which remnants can be found capping much of Lincoln County, is about 500 feet MSL. This is typified near Brookhaven in Section 5, Township 7 North, Range 8 East. Centered in the northwest 1/4 of Section 22, Township 5 North, Range 9 East, in southeastern Lincoln County, a roughly circular area approximately 1 mile in diameter is expressed above the local Citronelle alluvial surface, with a hilltop reaching an elevation of 570 feet MSL. This is 70 feet above the local Citronelle alluvial surface at 500 feet MSL. Gravity data centers this feature directly above Ruth Salt Dome, a shallow piercement type salt dome. Radial drainage off this feature and coarse sand and gravel exposed on the hilltop also support the presence of a geological structure.

2:30 GRAVEL PETROLOGY petrology, branch of geology specifically concerned with the origin, composition, structure, and properties of rocks, primarily igneous and metamorphic, and secondarily sedimentary.  OF THE PRE-LOESS TERRACE DEPOSITS

James E. Starnes, Mississippi Office of Geology, Jackson, MS 39289

The Pre-loess Terrace Deposits are early Pleistocene sand and gravel deposits overlain by loess that border the current floodplain of the Mississippi River in Mississippi and are probably equivalent to the Mounds Gravel Fm. of Missouri. The gravel portion of the deposits are dominantly composed of chert commonly containing Paleozoic fossils of crinoids, brachiopods, corals, bryozoans, gastropods, stromatolites, stromotoporids, and rare trilobites This list of trilobites is a comprehensive listing of all genera that have ever been included in the class Trilobita, excluding purely vernacular terms. The list includes all commonly accepted genera, but also genera that are now considered invalid, doubtful (nomina dubia . Chert varieties include oolitic o·o·lite   also o·o·lith
n.
1. A small round calcareous grain found, for example, in limestones.

2. Rock, usually limestone, composed of oolites.
, chalcedony chalcedony (kălsĕd`ənē) [from Chalcedon], form of quartz the crystals of which are so minute that its crystalline structure cannot be seen except with the aid of a microscope. , cornelian cornelian: see carnelian. , lace agate, jasper, banded chert, and tripolitic chert. Chert breccias and conglomerates are also common. In addition to chert and its varieties, the following gravel clasts have been identified in Pre-loess Terrace Deposits: Sioux and Baraboo Quartzite (fine to coarse-grained, pink to purple and often banded, occasionally brecciate brec·ci·ate  
tr.v. brec·ci·at·ed, brec·ci·at·ing, brec·ci·ates
To form (rock) into breccia.



brec
, pebble to boulder size), St. Francis Mountain rhyolite (fine to coarse-grained; pink, red, green, gray; massive or flow banded, pebble to cobble size), Keokuk geodes (cauliflower cherts lined inside with rock crystal quartz, quartz druse Druse: see Druze. , or chalcedony; pebble to large cobble size), sandstone (fine to coarse-grained; white, pink, red, green, gray; cobble to boulder size; some sandstones are loosely cemented as a result of quartz overgrowths displaying prismatic pris·mat·ic   also pris·mat·i·cal
adj.
1. Of, relating to, resembling, or being a prism.

2. Formed by refraction of light through a prism. Used of a spectrum of light.

3. Brilliantly colored; iridescent.
 crystal faces on individual grains and commonly containing authigenic An authigenic mineral or sedimentary rock deposit is one that was generated where it is found or observed. Can be used to characterize metamorphic minerals formed in situ  feldspars), Arkose arkose

Coarse sandstone that has formed by the disintegration of granite without appreciable decomposition. It thus consists primarily of quartz and feldspar grains.
 and weathered granite (pink, coarse-grained, pebble to cobble size, very rare), quartz (milky, pink, clear, gray; pebble to large cobble size). Authogentic and allogentic silicified si·lic·i·fy  
v. si·lic·i·fied, si·lic·i·fy·ing, si·lic·i·fies

v.tr.
To convert into or impregnate with silica.

v.intr.
To become converted into or impregnated with silica.
 wood, including fossil palm, is common.

3:10 LATE CRETACEOUS ECHINODERMS IN THE CENTRAL GULF STATES: AN UPDATE

George E. Phillips* and Charles N. Ciampaglio, Mississippi Museum of Natural Science The Mississippi Museum of Natural Science is the largest museum in state of Mississippi. Description
Located in Jackson, in Lefleur's Bluff State Park, the Mississippi Museum of Natural Science features aquariums, habitat exhibits, and nature trails specializing in the
, Jackson, MS 39202, and Wright State University, Celina, OH 45822

With the recent discovery of new species and new species occurrences, Late Cretaceous echinoderm echinoderm

Any of various marine invertebrates (phylum Echinodermata) characterized by a hard spiny covering, a calcite skeleton, and five-rayed radial body symmetry.
 paleontology in Mississippi, Alabama, and Arkansas is in need of significant updating. Given that no one has looked at any particular echinoderm group in the region in the last 50 years, a closer examination of echinoderms in the north-central Gulf is long overdue. For example, several new species of the cassiduloid Hardouinia have recently been identified in Santonian and Campanian deposits in the region. A pair of small burrowing spatangoids is abundant in a sandy marl horizon just above the b asal lag of the Maastrichtian Prairie Bluff Formation in Pontotoc County, Mississippi Pontotoc County is a county located in the U.S. state of Mississippi. As of 2000, the population was 26,726. Its county seat is Pontotoc6. Pontotoc is a Chickasaw word meaning "land of hanging grapes". . The crinoid Uintacrinus socialis, an important stratigraphic marker for Late Santonian deposits in the Western Interior and Europe, has now been found in the Tombigbee Sand Member of the Eutaw Formation in Mississippi. The bourgueticrinid Dunnicrinus, published from Late Maastrichtian deposits in Mississippi, the Netherlands, and Delaware, is now recorded from earlier Gulfian deposits in Mississippi. The type of Bourgueticrinus alabame nsis, the only specimen known to exist of this species, is now officially lost, requiring a search for a neotype ne·o·type
n.
A new specimen selected to replace a holotype that has been lost or destroyed.
. Asteroids, never before described from Mississippi or Alabama, are now documented. Articulated goniasterids have been recovered from the Campanian Mooreville Formation of Alabama, and Maastrichtian units in the north-central Gulf have yielded individual goniasterid ossicles Ossicles
The three small bones of the middle ear: the malleus (hammer), the incus (anvil) and the stapes (stirrup). These bones help carry sound from the eardrum to the inner ear.

Mentioned in: Otitis Media, Stapedectomy
.

3:30 EARLY CENOMANIAN PALEOCLIMATOLOGY paleoclimatology
 or palaeoclimatology

Scientific study of the extended climatic conditions of past geologic ages. Paleoclimatologists seek to explain climate variations for all parts of the Earth during any given geologic period, beginning with the time of
 AND PEDOGENIC PROCESSES IN THE NORTH AMERICAN WESTERN INTERIOR BASIN

David F. Ufnar, University of Southern Mississippi, Hattiesburg, MS 39406

Stable isotope mass balance modeling results of meteoric [[delta].sup.18]O values from the Cenomanian Stage of the Cretaceous Western Interior Basin (KWIB) suggest that precipitation and evaporation fluxes were greater than that of the present. Sphaerosiderite meteoric [[delta].sup.18]O values have been compiled from the Lower Tuscaloosa Formation of Mississippi (25[degrees]N paleolatitude), The Dakota Formation of Nebraska (35[degrees]N) and the Dunvegan Formation of British Columbia (55[degrees]N paleolatitude). These paleosol pa·le·o·sol  
n.
A soil horizon from the geologic past, usually buried beneath other rocks or recent soil horizons.



[New Latin : paleo- + Latin solum, soil.
 siderite siderite (sĭd`ərīt) or chalybite (kăl`ĭbīt), a mineral, varying in color from brown, green, or gray to black and occurring in nature in massive and crystalline form.  [[delta].sup.18]O values define a paleolatitudinal gradient ranging from -4.2 [per thousand] VPDB VPDB Vienna PeeDee Belemnite  at 25[degrees]N to -12.5 [per thousand] VPDB at 55[degrees]N. This trend is significantly steeper and more depleted than a Holocene meteoric calcite trend (27[degrees]N: -3.6 [per thousand]; 67[degrees]N: -7.4 [per thousand] VPDB). The steep latitudinal trend in meteoric [[delta].sup.18]O values may be the result of increased precipitation and evaporation fluxes (amount effects) under a more vigorous greenhouse-world hydrologic cycle. A stable-isotope mass balance model has been used to generate estimates of Cenomanian precipitation rates that range from 1500 mm/yr at 25[degrees]N paleolatitude to 3200 mm/yr at 45[degrees]N paleolatitude. Comparisons between Cenomanian siderite and Holocene calcite latitudinal trends show an amplification of Cretaceous low-latitude moisture deficits between 5-25[degrees]N paleolatitude and moisture surpluses between 40-60[degrees]N paleolatitude. The low latitude moisture deficits correlate with a mean annual average heat loss of 71 W/[m.sup.2] at 10[degrees]N paleolatitude (present, 16 W/[m.sup.2]). The increased precipitation flux and moisture surplus in the mid-latitudes corresponds to a mean average annual heat gain of 160 W/m2 at 50[degrees]N paleolatitude (present, 21 W/[m.sup.2]). The heat transferred to the atmosphere via latent heat of condensation was 7.0 x that of the present at 50[degrees]N. The intensified hydrologic cycle of the mid-Cretaceous greenhouse warming may have played a significant role in the poleward transfer of heat and more equable eq·ua·ble  
adj.
1.
a. Unvarying; steady.

b. Free from extremes.

2. Not easily disturbed; serene: an equable temper.
 global conditions.

3:50 Divisional Business Meeting
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Date:Jan 1, 2007
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