The Braen quarry: Haledon, Passaic County, New Jersey.
The Braen quarry in Haledon, Passaic County, New Jersey has been supplying crushed stone products since 1920. It is presently owned by Braen Stone Industries Inc., which acquired the operation in 1948.
During the quarry's first 78 years of existence, very few collector-quality specimens were gathered by mineral collectors. This was clearly evident from the scarcity of Braen minerals in local trap rock collections. In 1999, word began to spread of a highly mineralized zone having been exposed in the lowest benches of the pit. Within several months of the discovery, material from this section started appearing at area mineral shows.
Around 2000, Kurt Hennig, a New Jersey field collector, decided to visit the quarry office in an attempt to obtain permission to search for minerals. After speaking with management, he was granted access to the property under certain conditions. Collecting was to occur during normal business hours, and the wearing of the proper safety equipment was required to protect against injury. Over the next several years, Kurt and his friend Wes Conahay visited the operation frequently, and were often joined by one of the quarry owners in the hunt for specimens. At times, quarry machinery was utilized to expose mineralized areas and facilitate collecting. Management continued to gather specimen-grade material and set it aside, even when Hennig and Conahay were unable to make the trip. Thousands of specimens entered the mineral market from this prolific zone. Unfortunately, in 2003 specimen production was reduced to a trickle when the company decided that the liabilities associated with collecting were too great.
The Braen quarry is situated within the Newark Basin, a half-graben which formed during the late Triassic and early Jurassic periods as the supercontinent of Pangaea began to divide. The basin is approximately 190 km long and 50 km wide, and is filled with sedimentary and volcanic rocks having an estimated thickness of 6.8 km (Schlische, 1992; Olsen et al., 1996). It extends from southern New York through northeastern and central New Jersey and into southeastern Pennsylvania. In its northern portion the Newark Basin is bounded to the northwest by the Ramapo fault, which separates Precambrian rocks from the late Triassic and early Jurassic deposits inside the basin. At its eastern edge the basin is truncated by an erosional surface. The contact between the basal Stockton Formation and the underlying metamorphic rocks of the Piedmont Province is mostly obscured by the Hudson River and the glacial deposits that fill its valley. From Staten Island southwestward, Cretaceous and Tertiary sediments overlap the Newark Basin's southeastern and southern margins (Schlische 1992; Cummings, personal communication, 2007).
[FIGURE 1 OMITTED]
Three basalt flows, each separated by sedimentary deposits, lie within the upper third of the stratigraphic section of the Newark Basin. From the oldest to the youngest they are the Orange Mountain Basalt, the Preakness Mountain Basalt and the Hook Mountain Basalt. Jointly the three volcanic ridges are known as the Watchung Mountains. In the Haledon area the basalt flows and the sedimentary beds dip northwest at about 9-10 degrees (Volkert, 2006).
The Braen quarry is within the northern part of the Preakness Basalt outcrop area. The Preakness Basalt is the thickest extrusive body in the Newark Basin, reaching an estimated thickness of 300 meters (Olsen, 1980). Approximately 106 meters of the lower flow and the uppermost beds of the underlying Feltville Formation are exposed within the quarry. The lowermost 8 meters of the basalt contain four types of mineralized structures: (1) pillow lava, (2) scoria (3) amygdaloidal basalt and (4) veins.
The occurrence of pillow basalts (caused by the eruption of basaltic lava into a body of water) seems to have been much more isolated in the basal Preakness Basalt than in the Orange Mountain Basalt and has rarely been reported in the literature. At the basal contact of the Preakness Basalt, exposed in the quarry, the development of pillows is not continuous. In some places, massive, columnar basalt, which is capped by scoria, rests on the underlying Feltville sediments and is flanked laterally by accumulations of pillow lava. The basal contact at Braen is relatively flat, without any down-dropped areas or other indications of a pre-existing pond. This suggests that two separate pulses of lava arrived in rapid succession. The initial tongues of lava that invaded the area altered the local drainage, leading to the formation of ponds. It is in these ponds that the next surge of lava was able to form pillows. The columnar basalt resting directly on the sediments may represent one of the initial tongues (Cummings, personal communication, 2009).
The majority of minerals at the Braen quarry are located within the basal unit of the lower flow. Some mineralization also occurs in the basalt above this horizon, in veins that transect the flows and in vertically bulging, dome-like regions of amygdaloidal basalt, referred to as diapirs by Laskowich and Puffer (1990). Thus far only one diapir has been identified, approximately 9.1 meters high and 7.6 meters wide (Laskowich, personal communication, 2007). Prehnite, calcite and sulfides were the main constituents found within the irregularly shaped vugs of this structure.
Within the mineral-bearing zone at the base of the Preakness, the pillow basalt, averaging 4 meters in thickness, is the most productive of the mineralized structures. Voids generally measure around 18 cm, while the largest can be 1.5 meters across or greater. Quartz, datolite, calcite, anhydrite, hematite, goethite and pyrite are the primary components deposited in these openings. A flow-top amygdaloid of varying thickness rests atop the pillows. Sporadic pockets, between 10 and 60 cm, commonly lined with datolite or prehnite followed by zeolites, calcite and sulfides, are distributed unevenly within this layer. A scoriaceous cap 2.4 to 3.1 meters thick overlies the amygdaloid and includes numerous breccia cavities, some as large as 1.8 meters. These commonly contain well-crystallized zeolites, occasionally in association with datolite, prehnite, calcite and sulfides.
ORIGIN OF SECONDARY MINERALS
The secondary minerals found in the Braen quarry are the result of the hydrothermal alteration of the Preakness Basalt. The hydrothermal fluids are believed to be saline brines driven out of the lacustrine strata which enclose the Preakness Formation by the increasing depth of burial and the accompanying compaction within the Newark Basin.
The Preakness Formation probably underwent a period of burial and metamorphism prior to the main stage of secondary mineral deposition. In the low-temperature environment, minor alteration of the basalt occurred, producing clay and perhaps zeolites on the walls of the openings in the basalt. The principal phase of mineralization did not begin until some 15 to 20 million years after the basalt flow was extruded and buried. Late in the basin's history, sometime during the early to middle Jurassic period, there was a shift from crustal extension to shortening. This event was accompanied by extensive fracturing which allowed for a period of vigorous fluid circulation and high heat flow (Schlische et al., 2003). The saline formation brines flowed upward into the basal layer of the porous and permeable basalt flow. The presence of pumpellyite and minor epidote suggests that temperatures in the Preakness Basalt were elevated for a brief time to just over 200[degrees]C (Kristmannsdottir, 1979; Seki, 1972). As the temperatures rose, the host rock was attacked, broken down and partially replaced.
The formation brines in the sediments of the Newark Basin contained calcium and sodium sulfate. When these sulfate-rich fluids reacted with the basaltic glass and the calcium-rich clays and zeolites that resulted from burial metamorphism, the released calcium and silicon dioxide initially provided for the deposition of anhydrite, accompanied or immediately followed by chalcedony and quartz. Throughout the pillow lava, quartz coated a large percentage of the anhydrite that had developed. Although glauberite normally forms in such a depositional environment, no indications of the mineral have been found at the Braen quarry.
As temperatures increased, alteration of the permeable horizons within the basalt intensified. Not only the glassy part, but the basalt itself, was partially to totally replaced by a very fine-grained mineral assemblage that included chlorite, pumpellyite and epidote. In the permeable and glass-rich regions of the basalt there was an enhanced mix of elements that included components derived from the country rock and introduced by the hydrothermal fluid. In the higher-temperature environment quartz deposition declined markedly as other elements, mainly calcium, aluminum and boron, united with silica to form prehnite, datolite and other silicates. Like quartz, prehnite and datolite also crystallized over anhydrite.
Sulfides also formed during the time of peak temperatures within the Preakness Basalt. Among the sulfides that occur at the Braen quarry are pyrite, galena, wurtzite and sphalerite. The presence of these minerals distinguishes the rocks of the Braen quarry from those in the trap rock quarries within the Orange Mountain Basalt, where pyrite and zinc sulfides are either rare or absent. Their presence suggests that the mineralizing fluid that invaded the basalt at the Braen quarry was more chemically reduced than those responsible for mineralization at most of the region's better known sites. This subtle chemical difference may be due to the influence of the Feltville sediments that underlie the Preakness Basalt, that separate it from Orange Mountain Basalt, and that include a prominent black unit known as the Washington Valley Member. The Newark Basin brines, which migrated upward through this layer and into the Preakness Formation, may have caused a more reducing environment to occur locally, allowing for the deposition of pyrite and the zinc sulfides.
As the crystallization of prehnite and datolite began to wane, anhydrite began to dissolve. It was preserved only where permeability had been reduced to a very low level. The dissolution of anhydrite left the hollow cavities or molds in the quartz, datolite and prehnite that are such a well known feature of mineral specimens from the entire region.
The taking up of silica by later silicates is illustrated by the zeolites found at Braen. Their formation reflects a period of waning temperatures, reaction rates and, perhaps, fluid salinity. The common zeolites, including heulandite and stilbite, are calcium-dominated minerals that are fairly high in silica. Those that are lower in silica, including natrolite and analcime, are sodium-rich minerals that tend to develop in areas of higher fluid flux where more sediment-derived sodium was available.
Calcite precipitated throughout the secondary mineralization in the Preakness Basalt. The mineralizing fluids were in chemical equilibrium with the calcite-containing sediments of the basin. Through most of the paragenetic sequence calcite was locally stable relative to other minerals. At the end of the depositional event, with low temperatures and a thoroughly altered host rock, calcite was dominant among the minerals still being deposited.
The following is a compilation of all the validated species collected at the Braen quarry as of January 1, 2009.
Albite is found as elongated microscopic blades on scoriaceous basalt. Albite has also been seen as pseudomorphs after natrolite crystals.
Analcime NaAl[Si.sub.2][O.sub.6] * [H.sub.2]O
Analcime is a rare zeolite at the Braen quarry. Crystals up to 1.8 cm are found as isolated, opaque white trapezohedrons inside breccia cavities.
Anhydrite forms as blue crystal groups up to 14 cm in quartz and datolite pockets in the pillow basalt. A number of anhydrite specimens have been partially altered to gypsum. Rectangular crystal cavities after anhydrite are often found in quartz, datolite and cal cite. None of New Jersey's former or active trap rock quarries has produced more specimens of anhydrite than the Braen quarry.
[FIGURE 4 OMITTED]
[FIGURE 5 OMITTED]
[FIGURE 6 OMITTED]
[FIGURE 7 OMITTED]
[FIGURE 8 OMITTED]
Apophyllite-(KF) [KCa.sub.4] [Si.sub.8][O.sub.20](F,OH) * 8[H.sub.2]O
Apophyllite-(KF) (formerly known as fluorapophyllite) is relatively uncommon at the Braen quarry compared to most other New Jersey basalt quarries. It is collected as isolated crystals on datolite, prehnite or calcite, or directly attached to the walls of breccia cavities. The largest crystal measures 1.8 cm and exhibits a prismatic habit with dipyramidal modifications.
Barite occurs in the quartz-lined openings in the pillow basalt as isolated white crystals and bladed spherical rosettes up to 2 cm. Although small, the crystals and rosettes make for attractive specimens when resting on smoky quartz and amethyst.
Calcite is ubiquitous in the mineralized areas at the Braen quarry. It occurs in a wide variety of habits, but the scalenohedron and rhombohedron are the most common forms. Colors range from white to golden brown to a pink color caused by hematite on or inside the crystals. Crystals up to 12 cm are known, although most are much smaller. Many specimens display rectangular molds after anhydrite.
Chabazite Ca([Al.sub.2][Si.sub.4])[O.sub.12] * 6[H.sub.2]O
Only a few specimens of chabazite are known from the Braen quarry, the largest observed crystal measuring 1 cm. The chabazite crystals are pseudorhombohedral in habit, and very pale pink, white or colorless.
Chalcopyrite is found throughout most of the mineral horizons at the Braen quarry as brassy sphenoidal crystals ranging in size from 1 to 12 mm. Crystals are typically associated with other sulfides, making for showy specimens.
Chamosite forms as platy dark green to black microcrystals inside breccia cavities. This member of the chlorite group has also been collected as earthy brown pseudomorphs after analcime and natrolite. Positive identification was made by chemical analysis (B. Plotkin, personal communication 2007).
After calcite, datolite is the most common mineral at the Braen quarry. Nearly all datolite specimens are found as drusy plates of whitish to pale green crystals up to 1.3 cm completely lining cavities. Prehnite, apophyllite, calcite, hematite, heulandite and sulfides are known to form on the crystal faces. Datolite epimorphs after anhydrite are often found within crystal aggregates of datolite. Datolite has crystallized in all of the quarry's mineralized areas except in the veins.
Microscopic brownish green epidote crystals have been noted from a small vesicle containing pumpellyite in scoria. The tabular crystals, several of which are twinned, have been identified by their crystal morphology and by chemical analysis (B. Plotkin, personal communication 2007).
Galena is probably the rarest sulfide found in the Braen quarry. It forms sharp cubes up to 4 mm associated with calcite, datolite and other sulfides.
Acicular red and black goethite microcrystals are frequently found on or included in calcite and quartz within the pillow basalts and in the vesicular basalt cavities of the scoria.
Gypsum [CaSO.sub.4] * 2[H.sub.2]O
Transparent gypsum crystals formed as a result of the hydration of anhydrite. Free-standing transparent crystal groups and large crystallized masses are found in the pillow formation on quartz and datolite. Gypsum commonly includes sections which are partially altered to thaumasite. Microcrystals are also found in tiny vesicles of the scoria.
Hematite occurs in the pillow basalt as 1 to 7-mm black to red platy crystals perched on or included in quartz and calcite; these microcrystals can impart a reddish hue to other minerals.
Hemimorphite [Zn.sub.4][(OH).sub.2][Si.sub.2][O.sub.7] * [H.sub.2]O
Minute yellowish brown hemimorphite overgrowths viewed at 800X magnification have been found on sphalerite in a vesicle containing calcite and pumpellyite. Identification is based on the morphology and on chemical analysis (B. Plotkin, personal communication 2007).
Heulandite [(Na,Ca).sub.[2-3]][Al.sub.3][(Al,Si).sub.2][Si.sub.13][O.sub.36] * 12[H.sub.2]O
Heulandite is found commonly in the breccia cavities of the scoriaceous basalt. It is usually found as pearly coffin-shaped crystals in association with stilbite. The largest crystal found to date measures 2.7 cm, and sits isolated on a vesicular matrix. However, most crystals are approximately 1 cm and are colored white, golden or honey-brown.
[FIGURE 11 OMITTED]
Laumontite Ca([Al.sub.2][Si.sub.4])[O.sub.12] [4H.sub.2]O
Laumontite is the rarest zeolite to be identified from the quarry. The only known specimen, found in a natrolite vein, shows 4 to 5-mm white prismatic crystals on chabazite.
Mesolite [Na.sub.2][Ca.sub.2]([Al.sub.6][Si.sub.9])[O.sub.30] * [8H.sub.2]O
Clusters of mesolite microcrystals are often found as linings within the smallest vesicles of the scoriaceous basalt. Identification is based on the index of refraction (B. Plotkin, personal communication 2007).
Natrolite [Na.sub.2]([Al.sub.2][Si.sub.3])[O.sub.10] * 2[H.sub.2]O
Natrolite is another rare Braen quarry zeolite often found in seams which transect the columnar basalt, and in breccia pockets of the slag-like basalt. Specimens show jumbled acicular crystals up to 1.8 cm with pyramidal terminations.
[FIGURE 12 OMITTED]
[FIGURE 13 OMITTED]
[FIGURE 14 OMITTED]
Prehnite occurs as pale green botryoidal coatings, in spherules up to 2.5 cm and in spheroidal clusters. It is commonly associated with calcite, datolite, sulfides and rarely with zeolites. In contrast to most northern New Jersey quarries, prehnite is uncommon at the Braen quarry, and its distribution is limited to the amygdaloidal and scoriaceous basalt overlying the pillow basalt complex; it is also found in the openings in diapirs.
Pumpellyite [Ca.sub.2][MgAl.sub.2]([SiO.sub.4])([Si.sub.2][O.sub.7])[(OH).sub.2] * [H.sub.2]O
Pumpellyite is found as blue-green to black fibrous coatings inside breccia pockets.
Pyrite is rare in the New Jersey trap rocks outside of the Millington quarry, but at the Braen quarry it is the most common sulfide. Cubic to octahedral crystals typically occur in clusters and as coatings on earlier minerals. Although most pyrites are microscopic in size, some reach 1.2 cm.
Quartz lines numerous pockets of the pillow formation as crystals between 5 mm and 2.5 cm. Rectangular quartz molds after anhydrite are also plentiful in these openings. Varieties include colorless, amethystine and smoky quartz. The quartz crystals are usually so densely packed together that only their rhombohedral terminations are visible. It is also found in lavender botryoidal specimens up to 2.5 cm thick. Quartz is not present in the mineral-bearing horizons above the pillow lava.
Sphalerite (Zn, Fe)S
Sphalerite commonly forms on prehnite, datolite, calcite and quartz as sharp, green to reddish brown to black crystals up to 1.9 cm. They are highly prized by local trap rock collectors since they are rarely found outside of the Braen and Millington quarries.
Stellerite Ca([Al.sub.2][S.sub.7][O.sub.18]) * [7H.sub.2]O
Stellerite probably ranks as the Braen quarry zeolite most highly valued by collectors. Initially it was found as small translucent spheres and linings in cavities in the scoriaceous basalt, but large white to gray and cream-colored spheres up to 4 cm are now known. The best pocket produced between 25 and 30 attractive specimens with large, isolated, radiating spheres and spherical groups on drusy stellerite. Several of the spheroids have a ridge running across their midsections. The stellerite identification has been confirmed by chemical analyses (K. Hennig, personal communication 2007).
Stilbite [NaCa.sub.2]([Al.sub.5][Si.sub.13])[O.sub.36] * [14H.sub.2]O
Stilbite is the most interesting mineral discovered at the Braen quarry. Crystals occur as half and full bowties and radiating spherical groups in white, brown and tan. The most impressive specimens consist of isolated
spheres to 7.5 cm. Stilbite typically forms directly on the walls of the breccia cavities in the scoria.
Thaumasite [Ca.sub.3]Si([CO.sub.3])([SO.sub.4])[(OH).sub.6] * 12[H.sub.2] O
Thaumasite occurs in both datolite and quartz pockets in the pillow basalts as whitish compact masses. On some specimens thaumasite can be seen alongside unaltered gypsum.
Wurtzite (Zn, Fe)S
Wurtzite has not previously been reported from the New Jersey traps. A few examples have been collected at the Braen quarry, the best being a striated black 1.2-cm crystal on datolite, identified by the morphology and by chemical analysis (B. Plotkin, personal communication 2007).
[FIGURE 17 OMITTED]
[FIGURE 18 OMITTED]
[FIGURE 19 OMITTED]
[FIGURE 20 OMITTED]
[FIGURE 21 OMITTED]
[FIGURE 22 OMITTED]
[FIGURE 23 OMITTED]
After nearly 80 years in production, the Braen quarry has only recently become known as a source for fine specimens. Some of New Jersey's best quartz, stilbite and anhydrite have been recovered there, as well as the state's best examples of stellerite. Blasting will continue for approximately 14 more years. At present, the operation has moved through the extremely productive areas of the quarry and is excavating mostly barren rock. During the final years of mining, however, several buildings adjacent to the pit are scheduled to be razed to allow the removal of the underlying rock. It is expected that when the basal unit is reached again in this area, an abundance of fine mineral specimens will be uncovered. Whether the company will allow them to be salvaged at that time remains unknown.
Currently, the company does not allow collecting, and all such requests will be refused. In addition, management does not tolerate trespassing, and intends to prosecute any and all trespassers.
I would like to thank the management of Braen Stone Industries, Inc. for their permission to visit the quarry in order to study and photograph the local geology. I also greatly appreciate the assistance of Warren Cummings, a retired geologist formerly with the New Jersey Department of Transportation, who not only reviewed the article, but contributed information which was incorporated. Finally, thanks to Kurt Hennig, Eric Stanchich and Brad Plotkin for giving of their time to allow me to study and/or photograph their Braen collections.
FAUST, G. T. (1975) A review and interpretation of the geologic setting of the Watchung Basalt flows, New Jersey. United Sates Geological Survey Professional Paper 864-A, 1-42.
KENT, B. P., and BUTKOWSKI, B. (2000) Minerals of the Millington Quarry, Somerset County, New Jersey. Mineralogical Record, 31, 399-411.
KRISTMANNSDOTTIR, H. (1979) Alteration of basaltic rocks by hydrothermal activity at 190C-300 C, in MORTLAND, M. M., and FARNER, V. C, eds. Procedings of the International Clay Conference. Elsevier, 359-367.
LASKOWICH, C, and PUFFER, J. H. (1990) Volcanic diapirs of the Orange Mountain Basalt, New Jersey. New Jersey Academy of Science Bulletin, 35, 1-9.
MANSPEJZER, W. (1980) Rift tectonics inferred from volcanic and clastic structures, in: Field Studies of New Jersey Geology and Guide to Field Trips, 52, 314-50. New York State Geological Association Annual Meeting.
MASON, B. (1960) The trap rock minerals of New Jersey. New Jersey Geologic Survey Bulletin 64.
OLSEN, P. E., KENT, D. V., CORNET, B., WITTE, W. K., and SCHLISCHE, R. W. (1996) High-resolution stratigraphy of the Newark rift basin (early Mesozoic, eastern North America). Geology Society of America Bulletin, 108, 40-77.
OLSEN, P. E. (1980) The latest Triassic and Early Jurassic formations of the Newark Basin (Eastern North America, Newark Supergroup): stratigraphy, structure, and correlation. New Jersey Academy of Science Bulletin, 25, 25-51.
PETERS, T. A., PETERS, J. J., and WEBER, J. (1980) Famous mineral localities: Paterson, New Jersey. Mineralogical Record, 9, 157-179.
PUFFER, J. H. (1987) The Palisades sill and Watchung Basalt flows, northern New Jersey. Geological Society of America Centennial Field Guide--Northeastern Section, 91-96.
SCHALLER, W. T. (1932) The crystal cavities of the New Jersey Zeolite Region. U.S. Geologic Survey Bulletin 832, 463-503.
SCHLISCHE, R. W. (1992) Structural and stratigraphic development of the Newark extensional basin, eastern North America: evidence for growth of the basin and its bounding structures. Geological Society of America Bulletin 104.
SCHLISCHE, R. W., WITHJACK, M. O., and OLSEN, P. E. (2003) Relative timing of CAMP, rifting, continental breakup, and inversion: tectonic significance, in HAMES, W. E., MCHONE, G. C, RENNE, P. R., and RUPPEL, C, eds. The Central Atlantic Magmatic Province. American Geophysical Union Monograph 136, 33-59.
SEKI, Y. (1972) Lower grade stability limit of epidote in light of natural occurrences. Journal of the Geological Society of Japan, 78,405-413.
VOLKERT, R. A. (2006) Bedrock geologic map of the Paterson quadrangle, Passaic, Essex and Bergen Counties, New Jersey. New Jersey Geological Survey Geologic Map Series, GMS 06-6, Scale 1:24 000.
Frank A. Imbriacco III
1 Fox Hill Road
Edison, New Jersey 08820
|Printer friendly Cite/link Email Feedback|
|Author:||Imbriacco, Frank A., III|
|Publication:||The Mineralogical Record|
|Date:||Nov 1, 2009|
|Previous Article:||Famous mineral localities: Volodarsk-Volynski Zhitomir Oblast, Ukraine.|
|Next Article:||The museum directory.|