Devonian Black Shales Research Articles

Methods for distinguishing carbonized specimens of the presumed cephalopod aptychusSidetes(Spathiocaris) from the plantProtosalvinia(Foerstia)

The purpose of this note is to point out the similarities betweenProtosalvinia (Foerstia)andSidetes (Spathiocaris)and to discuss characters that can be used to distinguish the two taxa.ProtosalviniaClarke, 1885 (Figure 1.1-1.4), also commonly referred to by the junior subjective synonymFoerstia, is a plant fossil that is frequently noted as occurring in Upper Devonian black shale sequences of North America. This taxon has been of great interest to stratigraphers, paleoecologists, plant taxonomists, and plant morphologists over the years (see, for example, Winslow, 1962, p. 7, p. 22, fig. 3; Barron and Ettensohn, 1981, p. 30-31; Matthews, 1983; and Romankiw et al., 1988). Most workers in recent years have consideredProtosalviniato be a marine alga, but there is also evidence for a land plant affinity (Romankiw et al., 1988).

Rhenium and osmium isotopes in black shales and Ni-Mo-PGE-rich sulfide layers, Yukon Territory, Canada, and Hunan and Guizhou provinces, China

Rhenium and osmium abundances and osmium isotopic compositions were determined by negative thermal ionization mass spectrometry for samples of Devonian black shale and an associated Ni-enriched sulfide layer from the Yukon Territory, Canada. The same composition information was also obtained for samples of early Cambrian Ni-Mo-rich sulfide layers hosted in black shale in Guizhou and Hunan provinces, China. This study was undertaken to constrain the origin of the PGE enrichment in the sulfide layers. Samples of the Ni sulfide layer from the Yukon Territory are highly enriched in Re, Os, and other PGE, with distinctly higher Re/ 192Os but similar Pt/Re, compared to the black shale host. Re-Os isotopic data of the black shale and the sulfide layer are approximately isochronous, and the data plot close to reference isochrons which bracket the depositional age of the enclosing shales. Samples of the Chinese sulfide layers are also highly enriched in Re, Os, and the other PGE. Re/ 192Os are lower than in the Yukon sulfide layer. Re-Os isotopic data for the sulfide layers lie near a reference isochron with an age of 560 Ma, similar to the depositional age of the black shale host. The osmium isotopic data suggest that Re and PGE enrichment of the brecciated sulfide layers in both the Yukon Territory and in southern China may have occurred near the time of sediment deposition or during early diagenesis, during the middle to late Devonian and early Cambrian, respectively.

C-S-Fe Relationships and Stable Isotopes of Devonian Black Shales, MacKenzie Mountains, N.W.T. Canada

C-S-Fe Relationships and Stable Isotopes of Devonian Black Shales, MacKenzie Mountains, N.W.T. Canada

Age and depositional environment of upper devonian (early Frasnian to early famennian) black shales and limestones (Kellwasser facies) in the eastern Anti-Atlas, Morocco

The so-called Kellwasser facies consists of black bituminous limestones and shales which were deposited on pelagic platforms and in adjacent shallow basins. In contrast to the well-known European counterparts, Moroccan Kellwasser lithologies are extremely fossiliferous and, in addition to the predominating nektonic and planktonic, also contain different groups of benthic organisms. A first short-time Kellwasser episode during the lowermost Frasnian is succeeded, after an interval of grey nodular and crinoid limestone deposition, by a second longer one during the late Frasnian/early Famennian. On the platforms the upper member consists of slowly deposited cephalopod/tentaculitid/styliolinid coquinas and debris flows. Towards the basins they pass into shales with intercalated fine-grained sandstones and limestone lenses. This facies pattern reflects not only the regional palaeogeography but also local depositional environments on the platforms which were formed by differential subsidence, synsedimentary tensional tectonics and submarine erosion. Uni- or bidirectional bottom currents which reflect the overall palaeogeographic pattern are very pronounced in the platform environments but decrease towards the basins. The discontinuous stratigraphical record of the pelagic platforms images major sea-level oscillations which left only minor traces in the continuous basinal sequences. Widespread transgressions occurred during the Lowerasymmetricus, the Lower and Uppergigas, the Lowermarginifera and the Lowerexpansa Zones. They are separated by sea-level lowstands during the Middleasymmetricus/A. triangularis, therhomboidea and the (Middle?)praesulcata Zones. In contrast to the inferred fluctuations at the Frasnian/ Famennian transition in Euramerica, this interval in Morocco is represented by a more or less continuous highstand of sea-level.

Horizontal Drilling Opportunities in Ohio

Horizontal drilling has become commonplace in certain parts of Texas. The Austin Chalk is the favorite target, especially where fracture systems are present. The activity has become so intense that leases are now costly or nearly impossible to find. This type of activity was prevalent during the late oil boom, but with vertical wells. So, the same areas that were drilled then are being redone with horizontal drilling. In the past few months, carbonates with little or no evidence of fracture systems are being drilled with some success. Because of the difficulty in lease acquisition, operators are turning their attention elsewhere. Even though horizontal drilling has been conducted limitedly in the Devonian black shales, the Appalachian basin is an area that calls for attention. In Ohio, there have been instances of discoveries of one-well fields in both the Trenton and Trempealeau formations. The initial production from these wells ranges from a few to hundreds of barrels of oil per day. The lack of success in offset wells has been attributed to the interpretation that the producing wells were serendipitously drilled into a limited fractured reservoir. In most cases, the producer is surrounded by clusters of dry holes. These Ohio wellsmore » and wells in one other area are studied using well data, spectral and sonic logs, aerial photographs, side-looking radar surveys, and other data. The results are presented on structure contour and lineament maps, and quantitative log interpretations. The maps show the interpretations of those areas of fracture systems that might be viable targets for horizontal drilling.« less

Fractured Gas Reservoirs in the Devonian Shale of the Illinois and Appalachian Basins

The Devonian and Lower Mississippian black shale sequence of Kentucky includes the New Albany Shale of Illinois basin and the Ohio Shale of the Appalachian basin. Fractured reservoirs in the Ohio Shale contain a major gas resource, but have not been so prolific in the New Albany Shale. The authors propose two models of fractured shale reservoirs in both the Illinois and the Appalachian basins, to be tested with gas production data. (1) Where reactivated basement faults have propagated to the surface, the lack of an effective seal has prevented the development of overpressure. The resulting fracture system is entirely tectonic is origin, and served mainly as a conduit for gas migration from the basin to the surface. Gas accumulations in such reservoirs typically are small and underpressured. (2) Where basement faults have been reactivated but have not reached the surface, a seal on the fractured reservoir is preserved. In areas where thermal maturity has been adequate, overpressuring due to gas generation resulted in a major extension of the fracture system, as well as enhanced gas compression and adsorption. Such gas accumulations are relatively large. Original overpressuring has been largely lost, due both to natural depletion and to uncontrolled production. more » The relative thermal immaturity of the Illinois basin accounts for the scarcity of the second type of fractured reservoir and the small magnitude of the New Albany Shale gas resource. « less

The Long Rapids Formation: an Upper Devonian black shale in the Moose River Basin, northern Ontario

The Long Rapids Formation, a sequence of interbedded black shales, green–grey mudstones, and carbonates in the Moose River Basin of northern Ontario, is Late Devonian in age and has counterpart equivalents in the Michigan, Appalachian, and Illinois basins. The Long Rapids Formation has a maximum known thickness of 85 m and can be divided into three informal members. Based on conodont studies, the formation spans the Frasnian–Famennian age boundary.The Long Rapids Formation is an organic-rich, laminated, marine black-shale sequence interbedded with green–grey mudstones and concretionary carbonate interbeds and nodules. The environment of deposition was principally reducing, allowing for preservation of large amounts of organic matter both originating in the overlying water column and derived from terrestrial sources. The depositional basin was stratified, and anoxic bottom waters and oxic surface waters were separated by a pycnocline. The position of the pycnocline (or the absence of it) dictated the type of sediment facies deposited.The Moose River Basin in the Late Devonian was located on the Laurasian Continent, proximal to the equator, in an area where tropical weather conditions prevailed. Conditions were warm and wet along the Appalachian highlands, and farther inland they were warm and dry as a result of the rain-shadow effect. The black shales in the Long Rapids Formation represent a period of transgression of the large epicontinental Catskill Sea, and the green–grey mudstones and carbonates represent periods of minor eustatic or tectonic perturbations.Dark-coloured, organic-rich shale facies (sometimes with abundant bioturbation) are succeeded by lighter coloured shale or mudstone facies and carbonate facies in a repetitive fashion. The facies sequences appear to represent a three-part sedimentary package, or "rhythm", that is very common in the lower two members of the Long Rapids Formation. Bioturbation and total organic carbon content are less in the green–grey shales or mudstones, as well as in the carbonate facies, than in the darker shale facies.

Depositional Model for Upper Devonian Black Shale (Woodford Formation) in Permian Basin, West Texas and Southeastern New Mexico: ABSTRACT

Depositional Model for Upper Devonian Black Shale (Woodford Formation) in Permian Basin, West Texas and Southeastern New Mexico: ABSTRACT

Former Presence of Thick Post-Devonian Strata in Northern Appalachian Basin: Evidence from Fluid-Inclusion Studies: ABSTRACT

Along an 80-km long belt south of Syracuse, New York, the maximum fluid-inclusion homogenization temperatures (T{sub max}) of late-stage cements of the lower Middle Devonian Onondaga Limestone show a local high of 150{degree}-160{degree}C in central New York. T{sub max} decreases both west and east of this area reaching about 100{degree}C in outcrops near Buffalo and Albany, respectively. Southward from Albany, along the western margin of the Hudson Valley, T{sub max} again rises sharply to 170{degree}-180{degree}C in the Kingston area. The thermal alteration index (TAI) and vitrinite reflectance of the overlying Marcellus-Bakoven (Middle Devonian) black shales in central and eastern New York show a comparable trend. The east-west profile of T{sub max} of the Onondaga rocks as well as thermal maturity of the black shales show excellent correlation with similar profiles of authigenic magnetite in the Onondaga Limestone and of clay diagenesis and fission-track ages of the Middle Devonian Tioga Metabentonite Bed, as reported by others. The T{sub max} of the Onondaga Limestone is believed to have been attained during maximum burial, the extent of which can not be accounted for by the present thickness of post-Onondaga strata. As a result of an inferred late Paleozoic uplift, in western and easternmore » New York, 2-3 km of post-Devonian strata were removed, in central New York 4-5 km, and in southeastern New York 5-6 km were removed. The north-south variation in maximum burial along the Hudson Valley may be explained by additional impact of tectonic loading in the south.« less

Risk-Qualified Prediction of Gas Initial Potential and Production from Devonian Black Shales, West Virginia: ABSTRACT

Risk-Qualified Prediction of Gas Initial Potential and Production from Devonian Black Shales, West Virginia: ABSTRACT

Stratigraphy and Production Characteristics of Upper Devonian Black Shales and Siltstones, West Virginia: ABSTRACT

Prior to 1979, drilling for oil and gas from Upper Devonian clastic reservoirs in West Virginia was separated into two main trends; (1) oil and gas reservoirs in thin nearshore sandstones, or bundles of discontinuous marine sandstones and siltstones, associated with the Catskill delta and (2) gas reservoirs in organic-rich black shales in the finer clastic, more offshore facies farther to the southwest. Recent exploration and development drilling in the area between these two productive trends has provided sufficient control to carefully document key facies changes and intertonguing relationships. Fine-grained sandstones and siltstone bundles that extend into the area from the east are replaced by gray shales to the west. Black, organic-rich shales interfinger with, and are replaced by, nonorganic, gray marine shales to the east. Oil and gas production have been developed in these distal tongues of sandstones and siltstones and in the thin black shales that thicken to the west. Although exceptional wells have been drilled, the typical well in this area of recent drilling is marginally economic. Initial decline rates are high, and most wells will be short-lived, in contrast to the low-volume, long-term wells characteristic of the black shale reservoirs farther to the southwest. In general,more » productivity from black shale reservoirs increases progressively to the southwest, from fields associated with the detached Burning Springs anticline to fields that overlie the Rome trough in eastern Kentucky. The difference between opposite ends of this productive trend is significant. The average shale well to the southwest produces more gas in its thirtieth year than the average shale well to the northeast produces during second year on line.« less

Erosion on an anaerobic seafloor: Significance of reworked pyrite deposits from the Devonian of New York state

Several Devonian black shale units in New York State display conspicuous basal discontinuities marked by accumulations of exhumed and reworked pyrite nodules, tubes, and fossil steinkerns. This coarse debris is overlain by, and/or interlayered with, black, laminated shale. The most important level is the Leicester Pyrite Member, which occurs along a regional unconformity flooring black shale deposits of the basal Genesee Formation; the detrital pyrite occurs in discontinuous lenses both on, and slightly above this surface. Basal Genesee beds (Geneseo Shale Member) record westward overlap of basinal, anoxic muds during a major marine transgression (Taghanic onlap). The reworked pyrite deposit is regionally diachronous, as indicated by conodont data and shingling of lenses with basal Genesee beds which are successively younger from east to west. Pyrite, chemically unstable in aerobic bottom settings, was exhumed and concentrated on the sea floor during brief erosion episodes in a normally anaerobic environment. Lenses contain istinctive diagenetic pyrite structures (e.g., fossil steinkerns, burrow tubes) derived from muds underlying the discontinuities. Erosional reworking of pyrite on the sea floor is shown by mechanical breakage of pyrite grains, reorientation of geopetal stalactitic pyrite and compactional features, plus alignment of pyritic tubes by bottom currents. General absence of carbonate allochems in lenses is believed to reflect dissolution of carbonate, following its exhumation. Episodic, deep storm-generated turbulence was probably important in exhuming and transporting pyrite. However, shoaling internal waves, impinging the sediment-starved basin margin slope, may also have been important in scouring the bottom. A model of internal wave erosion during the Taghanic transgression is presented herein; we feel that such erosion, concentrated at or near the base of the pycnocline during a period of relative sea level rise, offers a particularly good explanation for the observed juxtaposition of Geneseo and other similar black shale deposits on erosional discontinuities. The diachronous character of Leicester lenses and associated black Genesee muds above the unconformity suggests a transient rather than fixed basin axis allowing for progressive westward burial of the unconformity and assiciated remanié deposits by onlapping black muds. Older and younger occurrences of resedimented pyrite are briefly described from other Devonian basinal units and are shown to have formed in about the same manner as the Leicester. Reworked pyrite is believed to be common, although seldom recognized, in Phanerozoic sediment-starved basinal settings. Moreover, detrital pyrite, analogous to that described herein, probably awaits discovery in certain modern marine basins.

Rb-Sr dating of diagenesis and source age of clays in Upper Devonian black shales of Texas

The Rb-Sr method can be used to date diagenetic events that have affected the illitic clays commonly found in sedimentary rocks. Diagenetic 1Md illite forms in equilibrium with pore-water Sr and appears to be a stable phase that is able to maintain a closed chemical system even under deep burial conditions. Meaningful analytical data can be obtained after careful size fractionation to separate coarse-grained, detrital 2M illite from finer-grained, diagenetic 1Md illite, followed by removal of exchangeable Rb and Sr with ammonium acetate. Rb-Sr data from the µ fraction of widely separated samples of Upper Devonian black shales in Texas fall on a single isochron having an age of 302 ± 4 m.y. Diagenetic illite must have formed rapidly in response to activity in the nearby Ouachita orogenic belt. In the middle Pennsylvanian, none of the shales was buried more than a few hundred metres, and so clay diagenesis may have been initiated by updip migration of hot brines out of the Ouachita tectonic zone. Later burial to as much as 7 km did not result in further diagenetic changes affecting the Rb-Sr system. Coarse-grained illite (2–1 µ ) from the west Texas Woodford Shale records an isochron age of the source region of 539 ± 18 m.y. This is an age not commonly encountered in rocks of North America, suggesting a derivation of Woodford clays from the southern continental landmass.

Geology of the Devonian black shales of the Appalachian Basin

Black shales of Devonian age in the Appalachian Basin are a unique rock sequence. The high content of organic matter, which imparts the characteristic lithology, has for years attracted considerable interest in the shales as a possible source of energy. The recent energy shortage prompted the U.S. Department of Energy through the Eastern Gas Shales Project of the Morgantown Energy Technology Center to underwrite a research program to determine the geologic, geochemical, and structural characteristics of the Devonian black shales in order to enhance the recovery of gas from the shales. Geologic studies by Federal and State agencies and academic institutions produced a regional stratigraphic network that correlates the 15 ft black shale sequence in Tennessee with 3000 ft of interbedded black and gray shales in central New York. These studies correlate the classic Devonian black shale sequence in New York with the Ohio Shale of Ohio and Kentucky and the Chattanooga Shale of Tennessee and southwestern Virginia. Biostratigraphic and lithostratigraphic markers in conjunction with gamma-ray logs facilitated long-range correlations within the Appalachian Basin. Basinwide correlations, including the subsurface rocks, provided a basis for determining the areal distribution and thickness of the important black shale units. The organic carbon content of the dark shales generally increases from east to west across the basin and is sufficient to qualify as a hydrocarbon source rock. Significant structural features that involve the black shale and their hydrocarbon potential are the Rome trough, Kentucky River and Irvine-Paint Creek fault zone, and regional decollements and ramp zones.

Oil and Gas Potential of Amazon Paleozoic Basins: ABSTRACT

The Paleozoic basins, covering an area of about 800,000 km2 (309,000 mi2) in the Amazon region, are elongate symmetrical intracratonic synclines filled with as much as 4,000 m (13,000 ft) of sediments, separated by basement uplifts or major arches and located in continental interior areas (as are the United States Illinois, Michigan, and Williston basins). These Amazon basins resulted from an initial crustal thinning followed by rifting with associated ultrabasic intrusions and, finally, cooling and subsidence. Gravity anomalies, coinciding with the axes of the synclines, support this genetic hypothesis. These synclines were filled during the Silurian-Devonian with one cycle of continental alluvial sediments grading upward to deltaic marine clastics and minor periglacial deposits. A regional unconformity separates the Devonian from the Permo-Carboniferous cycle when, following fluviodeltaic sedimentation, highly restricted marine conditions developed a sequence of evaporite deposits. Tectonics affected differentially these basins during the Triassic-Jurassic and Early Cretaceous, associated with widespread basic volcanism. A northeast-southwest thrust-fault system, branching southwest, characterizes a compressional orogenic province in the Upper Amazon basin. This compressional province, located in the Jurua River area, constitutes a major structural trend. Adjacent to those faults and extending for over 500 km (310 mi), large natural gas accumulations occur in several domal features. Sandstones of the Permian Monte Alegre Formation, sealed by evaporite strata, are the main reservoir rock. Geologic estimates of natural gas resources are presently rated at 120 billion m3 (4.237 tcf) and exploration follows the productive trend toward the west-southwest. The Middle Amazon basin, separated from the Upper Amazon by the Purus arch, was affected by lineament-block tectonics, also with associated volcanism and some local mild shearing. Minor domal features of Devonian periglacial Oriximina Formation sandstones comprise small subcommercial oil accumulations. In contrast with the Upper and Middle Amazon basins, the Lower Amazon basin has been the site of rifting since the Permo-Triassic. The rifting was associated with a nearby hot spot that uplifted the eastern part of the basin, forming the Gurupa arch. As a consequence of this uplift, a set of collapse grabens developed in the Lower Amazon basin. Potential reservoir rocks in Middle and Lower Amazon basins are Permian Monte Alegre and Devonian Oriximina sandstones. Major source rocks in al three basins are Devonian Barreirinha black shales. Organic geochemistry data indicate that both Upper and Lower Amazon basins are predominantly gas-prone, whereas the Middle Amazon basin shows potential for oil generation. Forecasts for the major exploratory trends in the Upper Amazon indicate a good possibility of extending the already discovered natural gas province. In the Lower Amazon basin, further exploration will consist in drilling well-defined structural features identified for the first time by seismic methods, with a possibility of discovering another gas province. Prospects in the Middle Amazon basin are for both oil and gas, but the main problem is identification of adequate structures, as well as stratigraphic traps. End_of_Article - Last_Page 1205------------

Oil and Gas Developments in New York in 1983

In 1983, 481 wells were completed in New York. In existing fields, 48 oil and 385 gas wells were completed. Exploratory drilling resulted in 5 new gas-field discoveries, 1 new oil-pool discovery, 32 extensions to existing gas fields, and 1 extension to an old, shallow oil field. All of the extensions were to Medina sandstone fields in western New York. One small Oriskany discovery was completed in Allegany County. In Cattaraugus County, a small Medina sandstone gas discovery was drilled in the northwestern part of the county and a small Upper Devonian sandstone oil extension was completed near the state line. In Chautauqua County, 17 extensions to known Medina gas fields were completed. A new Medina sandstone producing area was opened by a discovery in the Ellington area. One new oil pool was discovered in the Ellery area of the Akron structural trend. Two dry Devonian black shale tests were drilled by the New York State Energy Research and Development Authority (NYSERDA), one in Rushville field in Yates County and the other in Naples field in Ontario County. Columbia Gas completed a dry wildcat northeast of Albany in the Eastern Overthrust trend. The total depth of the well was 7,764 ft, and only a few small shows of gas were encountered. Oil production in 1983 was 867,429 bbl and gas production was 18,500 mmcf. The price for New York stripper crude was $30/bbl on January 1, 1983, and ended the year at $28/bbl. In 1983, 38 crew-weeks of reflection seismic work were accomplished in New York. FERC Section 107, Tight Formation, pricing for the Medina and Queenston in 10 additional counties was approved in January 1983. There will be continued Medina sandstone and Akron trend drilling in 1984. Akron oil production may boost the overall New York production slightly in 1984. Gas purchasers continued extensive shut-in periods during 1983 because of the oversupply of gas. Because of this, a slight decline in drilling is expected in 1984. Columbia Gas plans to drill a 10,500-ft wildcat in northwestern Vermont near Lake Champlain in the summer of 1984. The installation of gas-operated cogeneration electrical generating units increased in 1983, but this trend may be halted by a court ruling which allows for lower payment for the electricity generated.

Silurian and Lower Devonian of Southwestern Virginia: ABSTRACT

Thermal maturity of the Silurian and Lower Devonian rocks in Virginia west of New River decreases southwestward. Oil and gas shows are reported. The total thickness of Lower Devonian plus Silurian strata ranges from 52 to 1,000 ft (16 to 305 m), with a maximum in Buchanan County. Sandstones were derived from sources southeast of the central Appalachian basin, some from lands southeast of the outcrop belt, and some formed by reworking of sandstones within the outcrop area. Sandstones change northwestward to shales in the Clinch and Rose Hill Formations. In the Middle Silurian and Helderberg Group, sandstones grade northwestward to limestones. Limestones in the Hancock Formation change westward to dolomite. The Onesquethaw Stage is represented by sandstone, chert, and limestone assigned to the Wildcat Valley and Huntersville Formations. In the Middle Silurian (Keefer or Big Six sandstone) and Early Devonian (Wildcat Valley Sandstone), longshore currents carried sand across the southwest end of the basin toward Kentucky. Several regional unconformities are present. These unconformities are mostly related to sea level changes, but some are probably tectonic in origin. Five unconformities are significant: (1) at base of Silurian, (2) at base of upper Helderberg over much of the area, (3) at base of Oriskany Sandstone, (4) at base of Huntersville Formation, and (5) at base of Upper Devonian black shales in extreme western Virginia, where Chattanooga Shale overlies Middle Devonian to Middle Silurian strata. End_of_Article - Last_Page 1918------------

Geochemical investigations of paleozoic shales and carbonates in the Aachen region

In the western part of the Rheinisches Schiefergebirge geochemical investigations were carried out on Paleozoic black shales and carbonates in the Aachen region. Primary and secondary metal distributions were determined in selected units of sedimentary rocks by XRF-analysis and in stream sediments by AAS-analysis. The primary geochemical pattern and the results of geological studies reveal that Frasnian (Upper Devonian) black shales and nodular limestones were deposited in a restricted environment under euxinic conditions of a swell and basin facies. Black shales and nodular limestones are enriched in Zn and Cu resp., possibly indicating stratiform sulphide mineralization. Geochemical anomalies in stream sediments with increased values of Pb, Zn, Cd, Cu, Co, and Ni were found in areas of Lower Paleozoic sedimentary rocks and associated acid intrusives which are known to contain low grade sulphide mineralization of the “porphyry copper-type”.

Plants of Devonian-Mississippian Black Shales, Eastern Interior, U.S.A.: ABSTRACT

Macrofossils of the New Albany shale and equivalents of Late Devonian of Early Mississippian age in the east-central United States are known from three main floras or assemblages. One is almost entirely composed of Callixylon logs, slabs, End_Page 444------------------------------ and slivers, presumed to be driftwood permineralized after burial. Callixylon fossils are most abundant in the upper part of the Clegg Creek Member of the New Albany shale ()Famennian) and equivalent strata in western New York, Ohio, and contiguous areas, perhaps because these Progymnosperms reached the zenith of their development at that time. They also occur sporadically throughout the New Albany shale and equivalent strata. The principal geographic concentration of Callixylon is in western New York, principally in marine sediments, and on the west side of the Cincinnati arch. Callixylon is also sparsely and sporadically distributed in nearly all areas of outcrop of the Devonian black shales including the New Albany, Antrim, Kettle Point, and Ohio shales, and is found in Kinderhooki n age shales from Illinois and Tennessee. A second, and later, flora consists principally of permineralized wood pieces (phosphatized free-wood or concretions) of stems, rachises, petioles, and possibly even mid-veins of pinnules of diverse members of the Lycopsida, Sphenopsida, Cladoxylales, Coenopteridales, Progymnospermae, and Pteridospermae. A few of these disjunct pieces have been reconstructed into more complete plants known from the Catskill delta in western New York, Pennsylvania, and West Virginia. The principal concentration of these stem and petiolar segments is in the Falling Run Member of Sanderson Formation of the New Albany shale on the west side of the Cincinnati arch in southern Indiana and Kentucky, and in central Kentucky in the low saddle between the Cincinnati arch proper and its southward extension as th Nashville dome. This abundant distribution of minute stem axes and other such small plat fragments strongly suggests the source of these palnts to be a nearby island (Cincinnatia?). Alternatively, it is proposed that they have been concentrated by currents on a very shallow choal on or near a structurally positive submarine rise of the Cincinnati arch, or by floating algal mats in which the waterworn wood and leaf fragments became enmeshed as flotsam near some shore and were transported by these mats to more distant sites before the disintegration of the mats. The third type of macrofossil palnt assemblage is constituted of Foerstia. These plants are considered to be algal in origin and indicate no clear relationship either to distance from shore or depth of water. The main concentration is in middle and lower New Albany shale and equivalents. It is also found sparingly in West Virginia and Michigan and much farther west (one specimen from the Exshaw shale of Montana). End_of_Article - Last_Page 445------------

Oil and Gas Developments in New York in 1982

In 1982, 533 wells were completed in New York. In existing fields, 57 oil and 426 gas wells were completed. Exploratory drilling resulted in 4 new gas field discoveries, 1 deeper pool discovery, and 32 extensions to existing gas fields. Thirty of the extensions were to Medina sandstone fields in western New York. Pennzoil completed 2 Oriskany Sandstone gas discoveries in southeastern Cattaraugus County. Berea Oil & Gas drilled a dry downdip Medina sandstone test in the same general area. In Cayuga County, Devonian Energy drilled 3 dry Queenston tests and 1 dry Precambrian test. In Chautauqua County, 35 producers have been drilled in the northeast-southwest Akron (Bass Islands) trend. High levels of oil and gas production have occurred from fractured zones along this thrust-faulted anticlinal feature. Open flows of more than 2,400 BOPD and 60 MMCFGD have been reported. Two Devonian black shale gas tests were drilled in central-southern New York by the New York State Energy Research and Development Authority (NYSERDA). One, in Chemung County, was completed as a good gas producer, but the other, in Tioga County, was only a small producer. NYSERDA also drilled a geothermal test in the city of Auburn in central New York. The well was drilled to the Precambrian and is being tested for the production of saline formation water at 125°F for possible use in space heating. Oil production in 1982 was 831,491 bbl; gas production amounted to 18,760 mmcf. The price for New York stripper crude was $35/bbl on January 1, 1982, and ended the year at $30/bbl. In 1982, an estimated 24 crew-weeks of reflection seismic work was done in New York. Federal Energy Regulatory Commission (FERC) Section 107, tight formation, designation for the Medina in Chautauqua and Cattaraugus Counties was approved in January 1982. An application for Section 107 pricing for the Medina and Queenston in 10 additional New York counties was near approval at year end. Gas purchasers initiated extensive shut-in periods during 1982 because of the oversupply of gas. Contract renegotiations for a lower price for Section 107 gas were common. Because of this, a decline in drilling is expected in 1983. In early 1982, the U.S. Corps of Engineers gave final approval to drilling for gas in the eastern United States portion of Lake Erie. The New York portion consists of 373,000 acres. Columbia Gas has leased and done seismic work on extensive acreage in eastern New York and Vermont in the concealed eastern overthrust trend. It may drill a deep test on this acreage, near Albany, in 1983.