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1

Permian Basin as a radioactive waste repository  

International Nuclear Information System (INIS)

The Permian Basin comprises portions of many structural basins in which halite was deposited close together aerially during the Permian Period of time. It contains at least five areas where salt beds within a formation cumulatively total greater than 200 feet, and are overlain by between 1,000 and 5,000 feet of strata: the Colorado-Kansas, Kansas, Oklahoma-Texas, Clovis and Carlsbad areas. A few other areas within the Permian Basin may contain salt beds collectively greater than 200 feet thick. The Carlsbad area contains a great thickness of salt and covers a very large area. For the Clovis and Oklahoma-Texas areas there is little data available for the Texas portions. The Kansas area has the only halite mines with rooms comparable to those of the proposed waste repository facility. There is little data available for the Colorado-Kansas area, especially for the Colorado portion. The Permian Basin major tectonic elements were formed before deposition of Permian salt beds, and only minor igneous activity and possible fault movement is along the periphery. The greatest seismic activity is associated with the Nemaha Ridge along the northeast side of the Permian Basin, and there is no proven movement, only a suggestion of movement in the form of lineaments to have caused earthquakes. All of the Permian Basin is in zone 1 of Coffman and Cloud (1970) where only distant earthquakes may cause damage to structures; therefore, ground rupture is not anticipated in the Permian Basin during the time that the radioactive waste is dangerous

1975-01-01

2

Exploratory shaft facility preliminary designs - Permian Basin  

International Nuclear Information System (INIS)

The purpose of the Preliminary Design Report, Permian Basin, is to provide a description of the preliminary design for an Exploratory Shaft Facility in the Permian Basin, Texas. This issue of the report describes the preliminary design for constructing the exploratory shaft using the Large Hole Drilling method of construction and outlines the preliminary design and estimates of probable construction cost. The Preliminary Design Report is prepared to complement and summarize other documents that comprise the design at the preliminary stage of completion, December 1982. Other design documents include drawings, cost estimates and schedules. The preliminary design drawing package, which includes the construction schedule drawing, depicts the descriptions in this report. For reference, a list of the drawing titles and corresponding numbers are included in the Appendix. The report is divided into three principal sections: Design Basis, Facility Description, and Construction Cost Estimate. 30 references, 13 tables

1983-01-01

3

Permian Basin location recommendation report  

International Nuclear Information System (INIS)

Candidate study areas are screened from the Palo Duro and Dalhart Basin areas using data obtained from studies to date and criteria and specifications that consider: rock geometry; rock characteristics; human intrusion potential; surface characteristics; and environmental and socioeconomic conditions. Two preferred locations are recommended from among these areas for additional characterization to identify potential National Waste Terminal Storage (NWTS) salt repository sites. One location, in northeastern Deaf Smith County and southeastern Oldham County, is underlain by two salt units that meet the adopted screening specifications. The other location, in northcentral Swisher County, is underlain by one salt unit that meets the adopted screening specifications. Both locations have several favorable features, relative to surrounding areas, and no obviously undesirable characteristics. Both lie wholly on the Southern High Plains surface, are in relatively sparsely populated areas, contain no unique land use conflicts, and comprise large enough geographic areas to provide flexibility in site selection. Data gathered to date indicate that these locations contain salt units sufficient in thickness and in depth for the safe construction and operation of the underground facilities under consideration. 93 references, 34 figures, 6 tables

1983-01-01

4

77 FR 65446 - Iowa Pacific Holdings, LLC and Permian Basin Railways-Control Exemption-Cape Rail, Inc. and...  

Science.gov (United States)

...and Permian Basin Railways--Control Exemption--Cape Rail, Inc. and Massachusetts Coastal Railroad, LLC...owned subsidiary, Permian Basin Railways (Permian), Cape Rail, Inc. (Cape), P. Christopher Podgurski (Podgurski),...

2012-10-26

5

Non-hydrocarbon components of Carboniferous-sourced gas in the southern Permian basin, northwest Europe  

Energy Technology Data Exchange (ETDEWEB)

Natural gas sourced from Carboniferous coal-bearing strata is produced from Carboniferous, Permian and Triassic reservoirs in the Southern Permian Basin in northwest Europe. The composition of this gas has been reviewed.

Gras, R.; Clayton, C.J. [Schlumberger Geoquest, Montrouge (France). Africa Mediterranean Region

1998-05-01

6

Structure of the Anayet Permian basin (Axial Zone, Central Pyrenees)  

Science.gov (United States)

The Anayet Permian basin was generated by strike-slip tectonics that opened subsident basins with pull-apart geometries in the western Spanish Axial Zone (between the Aragon and Tena valleys). A continental succession of Permian age, that represents the first post-variscan deposits in the area, fills the basin and covers discordantly Devonian to Carboniferous limestones, sandstones and slates. Permian deposits have been classically divided in four main detrital groups, with three basic volcanic episodes interbedded (Gisbert, 1984, Bixel, 1987): the Grey Unit (50-120 m, Estefanian to Kungurian) with slates, conglomerates, tobaceous slates, coal and pyroclastic deposits, the Transition Unit (50 m maximum) showing grey and red sandstones and lutites with oolitic limestones intercalated, the Lower Red Unit (250 m) composed of cross-bedded red sandstones and andesitic volcanic rocks at the top, and finally the Upper Red Unit (400 m minimum, top eroded) formed by three fining up megasequences of carbonates, red sandstones and lutites with lacustrine carbonates intercalated and alkali basalts at the top. Increasingly older rocks are found towards the western part of the basin, where its depocenter is located. South-vergent angular folds deform the Permian sedimentary succession. Fold axes are N115 °E-trending, almost horizontal and are characterized by a remarkably constant orientation. Folds exhibit a long limb dipping slightly to the north and a short vertical limb, occasionally reversed. In the Anayet basin four main folds, with a wavelength of 400 m, can be distinguished, two anticlines and two synclines, with minor folds associated. Related to the angular folds an axial plane foliation, E-trending and dipping 40 to 60° to the north, is developed in the lutites. The more competent rocks, conglomerates and breccias, only locally show a spaced fracture cleavage. No main thrusts have been detected in Permian rocks. However, minor scale decollements, usually low angle to bedding-parallel, have been identified along low-dipping limbs of the folds. They can be recognized due to the high colour contrast between the red-coloured Permian beds and the concentration of calcite veins in the decollements. The development of the structures above described has to be linked to the Alpine compressional tectonics. This interpretation is supported by the good correlation in geometry and orientation between the structures observed in the Permian basin and in southernmost areas of the South Pyrenean Zone, where the deformation is imprinted in Cretaceous to Tertiary rocks. In this regard, the southern border of the Anayet basin, at least in the western part, can be interpreted as a normal fault reactivated as a high-angle reverse fault during the positive inversion tectonics induced by the Alpine Orogeny. Bixel, F., 1987. Le volcanisme stephano-permien des Pyrenees petrographie, mineralogie, geochimie. Cuadernos de Geología Ibérica 11, 41-55. Gisbert, J., 1984. Las molasas tardihercínicas del Pirineo, in: Geología de España. Libro Jubilar de J. M. Ríos, Comba, J.A. (Ed.), IGME, Madrid, 168-186.

Rodriguez, L.; Cuevas, J.; Tubía, J. M.

2012-04-01

7

Forward stratigraphic modeling of the Permian of the Delaware Basin  

Energy Technology Data Exchange (ETDEWEB)

Permian platform-to-basin strata of the Delaware Basin In west Texas and New Mexico represent one of the world`s most complete, best studied, and most hydrocarbon productive records of this geologic period in the world. This superb marriage of a refined stratigraphic framework and active exploration provided impetus to develop a forward stratigraphic model of this section to better predict the distribution of reservoir and seal relationships. The approximately 30 m.y. interval modeled is composed of 2 km of platform strata and 3 km of basinal strata divided into 8 composite sequences (average 3 m.y. duration) and 45 high-frequency sequences (400 ky m.y. duration). A 130 km dip section through the basin margin Guadalupe/Deleware Mountain outcrop is inversely modeled to derive local tectonic subsidence and a sea level curve for the Permian. In this process, the highest and lowest shoreline positions of each sequence are interpreted based on facies description which are assumed to approximate the highest and lowest relative sea level. A eustatic sea level curve is calculated by restoring these shoreline positions and removing local tectonic subsidence using a polynomial fit to the derived relative sea level curve. The quantitatively constrained curve for the Permian contains 2nd, 3rd, and 4th order 180m. This quantitatively constrained accommodation history (calculated eustatic curve and subsidence history) are input into the PHIL forward modeling program. Model variables of sediment supply are depositional system are adjusted to match known outcrop relations. The resulting model is potentially capable of predicting stratigraphy elsewhere in the basin using only subsidence history data from the inverse model.

Qiucheng, Ye; Kerans, C.; Bowman, S. [Univ. of Texas, Austin, TX (United States)] [and others

1996-12-31

8

Lower Permian Dry Mountain trough, eastern Nevada: preliminary basin analysis  

Energy Technology Data Exchange (ETDEWEB)

The Lower Permian Dry Mountain trough (DMT) is one of several basins that developed during the Late Pennsylvanian to Permian along the western edge of the North American continent. A tectonic mechanism has been suggested for the subsidence of the DMT, possibly due to reactivation of the Antler orogenic belt during the waning stages of Ancestral Rocky Mountain deformation. The DMT records marked subsidence with the appearance during the Artinskian (latest Wolfcampian) of a deeper water facies that consists of thin-bedded silty micrites and micritic mudstones rich in radiolarians and sponge spicules, characterized by a relative abundance of ammonoids, and rarer conodonts and Nereites ichnofacies trace fossils. Taxa recovered from a distinctive concretionary horizon at various locations provide an Artinskian datum on which to palinspastically reconstruct the DMT paleogeography. These taxa include ammonoids: Uraloceras, Medlicottia, Marathonites, Crimites, Metalegoceras, properrinitids; and conodonts: Neogondolella bisselli, Sweetognathus whitei, S. behnkeni, and Diplognathodus stevensi. The western margin facies of the DMT consists of Permian Carbon Ridge/Garden Valley Formations. Here, lowermost black Artinskianage euxinic micrites, considered a potential source rock for petroleum generation, are overlain by base-of-slope carbonate apron deposits, which, in turn, are overlain by base-of-slope carbonate apron deposits, which, in turn, are overlain by a thick, eastwardly prograding conglomerate wedge. Seismic profiles across Diamond Valley indicate a 3.0-4.6-km thick Tertiary sequence above the Paleozoic strata.

Schwarz, D.L.; Snyder, W.S.; Spinosa, C.

1987-08-01

9

Feasibility study of heavy oil recovery in the Permian Basin (Texas and New Mexico)  

International Nuclear Information System (INIS)

This report is one of a series of publications assessing the feasibility of increasing domestic heavy oil production. Each report covers select areas of the United States. The Permian Basin of West Texas and Southeastern New Mexico is made up of the Midland, Delaware, Val Verde, and Kerr Basins; the Northwestern, Eastern, and Southern shelves; the Central Basin Platform, and the Sheffield Channel. The present day Permian Basin was one sedimentary basin until uplift and subsidence occurred during Pennsylvanian and early Permian Age to create the configuration of the basins, shelves, and platform of today. The basin has been a major light oil producing area served by an extensive pipeline network connected to refineries designed to process light sweet and limited sour crude oil. Limited resources of heavy oil (10'' to 20'' API gravity) occurs in both carbonate and sandstone reservoirs of Permian and Cretaceous Age. The largest cumulative heavy oil production comes from fluvial sandstones of the Cretaceous Trinity Group. Permian heavy oil is principally paraffinic and thus commands a higher price than asphaltic California heavy oil. Heavy oil in deeper reservoirs has solution gas and low viscosity and thus can be produced by primary and by waterflooding. Because of the nature of the resource, the Permian Basin should not be considered a major heavy oil producing area

1993-01-01

10

Feasibility study of heavy oil recovery in the Permian Basin (Texas and New Mexico)  

Energy Technology Data Exchange (ETDEWEB)

This report is one of a series of publications assessing the feasibility of increasing domestic heavy oil production. Each report covers select areas of the United States. The Permian Basin of West Texas and Southeastern New Mexico is made up of the Midland, Delaware, Val Verde, and Kerr Basins; the Northwestern, Eastern, and Southern shelves; the Central Basin Platform, and the Sheffield Channel. The present day Permian Basin was one sedimentary basin until uplift and subsidence occurred during Pennsylvanian and early Permian Age to create the configuration of the basins, shelves, and platform of today. The basin has been a major light oil producing area served by an extensive pipeline network connected to refineries designed to process light sweet and limited sour crude oil. Limited resources of heavy oil (10'' to 20'' API gravity) occurs in both carbonate and sandstone reservoirs of Permian and Cretaceous Age. The largest cumulative heavy oil production comes from fluvial sandstones of the Cretaceous Trinity Group. Permian heavy oil is principally paraffinic and thus commands a higher price than asphaltic California heavy oil. Heavy oil in deeper reservoirs has solution gas and low viscosity and thus can be produced by primary and by waterflooding. Because of the nature of the resource, the Permian Basin should not be considered a major heavy oil producing area.

Olsen, D.K.; Johnson, W.I.

1993-05-01

11

Feasibility study of heavy oil recovery in the Permian Basin (Texas and New Mexico)  

Energy Technology Data Exchange (ETDEWEB)

This report is one of a series of publications assessing the feasibility of increasing domestic heavy oil production. Each report covers select areas of the United States. The Permian Basin of West Texas and Southeastern New Mexico is made up of the Midland, Delaware, Val Verde, and Kerr Basins; the Northwestern, Eastern, and Southern shelves; the Central Basin Platform, and the Sheffield Channel. The present day Permian Basin was one sedimentary basin until uplift and subsidence occurred during Pennsylvanian and early Permian Age to create the configuration of the basins, shelves, and platform of today. The basin has been a major light oil producing area served by an extensive pipeline network connected to refineries designed to process light sweet and limited sour crude oil. Limited resources of heavy oil (10`` to 20`` API gravity) occurs in both carbonate and sandstone reservoirs of Permian and Cretaceous Age. The largest cumulative heavy oil production comes from fluvial sandstones of the Cretaceous Trinity Group. Permian heavy oil is principally paraffinic and thus commands a higher price than asphaltic California heavy oil. Heavy oil in deeper reservoirs has solution gas and low viscosity and thus can be produced by primary and by waterflooding. Because of the nature of the resource, the Permian Basin should not be considered a major heavy oil producing area.

Olsen, D.K.; Johnson, W.I.

1993-05-01

12

Paleomagnetic investigation of Upper Permian sediments in the South Junggar Basin, China  

Science.gov (United States)

Lacustrine organic-rich mudstones of the Upper Permian Lucaogou Formation are a significant petroleum source bed throughout most of the Junggar basin in northwest China, and paleomagnetic data may provide insight into tectonic conditions prevalent during their deposition. Secondary magnetizations were removed from 180 samples from 29 sites within the South Junggar basin. Characteristic magnetizations of these samples were either revealed directly during thermal demagnetization or were calculated from great circle trajectories. The primary nature of the characteristic magnetization is attested to by a positive fold test, by exclusively reversed magnetizations which are consistent with the mid-Carboniferous to Late Permian Kiaman reversed interval for the geomagnetic field, and by relatively low levels of thermal maturity found in the mudstones. Tectonically corrected remagnetization circles and direct observations combined give a steep direction (I = -61.9°, D = 163.0°, k = 17, n = 78 specimens). The steep mean inclination recorded within the lacustrine organic-rich mudstones suggests that Junggar was situated near its present-day latitude during deposition of the mudstones in Late Permian times, consistent with the marginal ocean basin origin for Junggar that has been proposed based upon stratigraphic relationships. Our data suggest that Junggar may always have been associated with the northern continents of Laurasia, initially as a pre-Permian marginal ocean basin north of the Tethys and subsequently as a Permian, Mesozoic, and Cenozoic nonmarine foreland basin.

Sharps, Robert; Li, Yianping; McWilliams, Michael; Li, Yongan

1992-02-01

13

Facies and diagenesis of Grayburg-San Andres dolomite reservoirs, Central Basin platform, Permian basin  

Energy Technology Data Exchange (ETDEWEB)

Porous dolomites of the Grayburg and San Andres Formations (Permian, Guadalupian) form major hydrocarbon reservoirs on the Central Basin platform of the Permian basin. Wireline-log and core studies reveal a shallowing-upward carbonate shelf sequence, from 250 to 300 ft thick, in each of five fields that lie along 55 mi of the eastern edge of the platform. The sequence consists of (1) a basal unit of open shelf dolomudstones and bioturbated fusulinid dolowackestones/packstones; (2) a middle unit of shallow shelf dolomudstones and non-skeletal dolopackstones/grainstones; and (3) an upper unit of arid coastline dolomudstones, quartz siltstones, and evaporites that grade into the overlying Queen Formation. Reservoir zones averaging greater than 9% intercrystalline and moldic porosity and 10-md permeability are best developed in the middle unit of the depositional sequence. Diagenesis occurred in two stages. Stage 1, during deposition and earliest burial, involved submarine cementation, pervasive dolomitization, leaching of grains, minor dolomite cementation, and sulfate cementation and replacement; and stage 2, near maximum burial depth and during subsequent uplift, included fracturing, anhydrite cementation, minor calcite replacement of anhydrite, and gypsum and kaolinite formation.

Harris, P.M.; Garber, R.A.

1986-05-01

14

The not so simple relationship between seismicity and oil production in the Permian Basin, west Texas  

Science.gov (United States)

We have relocated seismicity occurring in the Permian Basin of west Texas between 1975 and 1979 using three-dimensional velocity models constructed from well log information and compared the locations to detailed geological and geophysical models of specific oil fields. The seismicity appears to be related to a variety of causes including migration of naturally occurring overpressured fluids, tectonic activity, reservoir production, and enhanced recovery operations. Many earthquakes may represent a combination of these effects. Although the Permian Basin is the site of numerous oil and gas fields, only a limited number of fields appears to be associated with seismicity. We find that there are similarities in the structural setting in the fields associated with seismicity. Furthermore, fields within the Delaware Basin that are associated with seismicity are located in regions of high vertical and lateral fluid pressure gradients related to an overpressured zone within the Delaware Basin.

Doser, D. I.; Baker, M. R.; Luo, M.; Marroquin, P.; Ballesteros, L.; Kingwell, J.; Diaz, H. L.; Kaip, G.

1992-09-01

15

Geochemical characteristics of Carboniferous-Permian coal-formed gas in Bohai Bay Basin  

Energy Technology Data Exchange (ETDEWEB)

Coal-formed gas reservoirs have been found in several depressions in Bohai Bay Basin. The gas was mainly generated by the Carboniferous-Permian coal measures, which are good source rocks. The exploration of coal-formed gas has a broad prospect. The main reservoirs of the coal-formed gas are Ordovician, Carboniferous-Permian, and Paleogene stratum. Coal-formed gas in the Bohai Bay Basin is chiefly composed of hydrocarbon gases. The percentage content of carbon dioxide is more than that of the nitrogen gas. The stable carbon isotope values of the hydrocarbon gases of different depressions and different reservoirs usually reversed. The reversed values of gas samples account for 52.1% of all the samples. Reversion values of the carbon isotope are mainly because of the mixing of gases from same source rocks but with different maturity. Among the three main reservoirs, coal-formed gas preserved in Paleogene stratum has the heaviest carbon isotope, the second is the gas in Carboniferous-Permian stratum, and the Ordovician gas possesses the lightest carbon isotope. Based on the analysis of the characteristics of carbon isotope of hydrocarbon gases in well Qishen-1 and the distribution of the Carboniferous-Permian coal measures, the gas of the well is derived from the high-matured Carboniferous-Permian coal measures.

Shipeng Huang; Fengrong Liao; Xiaoqi Wu [PetroChina, Beijing (China). Research Institute of Petroleum Exploration & Development

2010-03-15

16

Similarity of Grayburg/San Andres dolomite reservoirs - Eastern edge of Central Basin platform, Permian basin  

Energy Technology Data Exchange (ETDEWEB)

Porous dolomites of the Grayburg/San Andres Formations (Permian, Guadalupian) form major hydrocarbon reservoirs along the eastern edge of the Central Basin platform of the Permian basin, Texas. A comparison of the lithologic descriptions and depositional models for these reservoirs shows that although substantial local variation exists, the overall generalized vertical sequence and, particularly, the occurrence of porous shoal grainstones are strikingly similar. Data presented in this pilot study comes from the Gulf Oil 223-R J. T. McElroy Cons. well in McElroy field, the Gulf Oil 35 E.N. Snodgrass well in Waddell field, and the Gulf Oil 1359-56 C.A. Goldsmith et al well in Goldsmith field. Grayburg/San Andres reservoirs in all three fields occur mainly in the middle part of a shallowing-upward carbonate-shelf sequence that is 250-300 ft thick. The sequence consists of: (1) basal open-shelf, bioturbated dolowackestones/packstones; (2) middle shallow shelf fusulinid dolowackestones overlain by nonskeletal shoal dolopackstones/grainstones; and (3) upper variable intertidal/supratidal deposits that grade into the Queen Formation. The depositional sequence formed in a regional facies tract of shallow-water shelf and shoal environments with related tidal-flat and evaporitic (sabkha) sediments. The facies developed during easterly progradation across a deeper water open shelf. Porosity was formed by near-surface dolomitization and minor dissolution. Early and late evaporite plugging reduced porosity, so reservoir zones average 9% intercrystalline and moldic porosity with 10-md permeability.

Garber, R.A.; Harris, P.M. (Chevron Oil Field Research Co., La Habra, CA (USA))

1987-02-01

17

McElroy Field, Permian Basin, West Texas: Cyclic sequence dolomite reservoir of Central Basin platform  

Energy Technology Data Exchange (ETDEWEB)

The McElroy field, located in Crane and Upton Countries of west Texas, is one of several carbonate reservoirs developed along the eastern margin of the Central Basin platform. The reservoir rock at McElroy consists of Permian System (Guadalupian Series) dolomite of the Grayburg Formation. The Grayburg dolomite and the underlying San Andres Formation were formed as shallowing-upward carbonate sequences. The carbonate facies are overlain by the Queen Formation, an evaporite-dominated unit that serves as the reservoir seal. The Grayburg Formation carbonates consist of dolomitized lime mudstones, wackestones, pelletal and skeletal packstones, and ooid grainstones deposited in subtidal to supratidal environments. Facies prograde eastward toward the Midland basin, suggesting relative sea level lowering or progressive shallowing. The westward limit of the McElroy field is determined by pinch out of reservoir carbonates that interfinger with supratidal nodular and bedded anhydrite. The reservoir petrophysical characteristics are defined by diagenetic overprinting on primary carbonate depositional fabrics. The principal diagenetic processes include dolomitization, anhydrite occlusion of primary porosity, and leaching. McElroy, which was discovered in 1926, produces approximately 13,500 BOPD. This Chevron-operated field has 2.2 billion bbl of oil in place; 329 million bbl have been produced from nearly 1,600 wells. The field is currently under waterflood and is being evaluated for potential CO/sub 2/ injection.

Chalcraft, R.G.; Ward, R.F.

1988-01-01

18

Physical properties of Permian bituminous coals from the Sydney Basin, New South Wales  

Energy Technology Data Exchange (ETDEWEB)

This laboratory study, as part of a research programme on channel wave propagation in coal seams, looked at the densities and velocities (compressional and shear) of some Permian bituminous coals to elicit information on elastic properties, velocity variability and anisotropy, and dynamic elastic moduli. Resistivities and porosities were investigated also to provide basic information for surface, subsurface, and borehole data analyses in coal exploration and exploitation in the Sydney basin.

Greenhalgh, S.A.; Emerson, D.W.

1982-04-01

19

The problems of Paleozoic beds and reconstruction of the Middle Permian sedimentary basin in western Slovenia  

Directory of Open Access Journals (Sweden)

Full Text Available In the first part of paper geologic data from smaller outcrops of Val Gardena Formation in west Slovenia are assembled. Together with the already published information from larger outcrops they permit the reconstruction of the Middle Permian sedimentary basin on which the accent of paper is based. Attention is drawn to general problems of Upper Paleozoic beds, and conclusions regarding lithologic, stratigraphic and structural control of uranium and copper deposits in this part of Slovenia are given.

Ivan Mlakar

2003-01-01

20

Carboniferous-Lower Permian carbonate reservoirs of the Timan-Pechora Basin  

Energy Technology Data Exchange (ETDEWEB)

The Carboniferous-Lower Permian carbonate succession of the Timan-Pechora basin is a major hydrocarbon-bearing complex, hosting about half of the oil and nearly a third of the gas reserves of the basin. The succession represents the last episode of carbonate deposition on the northeastern margin of the Russian platform before the closure of the Ural seaway in the mid-Permian. The lower part of the succession (upper Visean-Moscovian) contains three major transgressive-regressive sequences. Depositional facies ranged from nearshore carbonate-shale-evaporite through shallow shelf detrital carbonates to outer-shelf carbonate-siliceous shale. The most pronounced regression during this interval occurred during the Serpukhovian, when marine sabkhas covered vast portions of the carbonate platform. Late Carboniferous-Early Permian sedimentation was complicated by the onset of Uralian tectonism. Flysch from the encroaching orogen accumulated initially in the east, advanced westward across the passive margin, and finally covered the carbonate platform in Artinskian-Kungurian time. Simultaneously, structural inversion along the Pechora-Kolva aulacogen and elsewhere provided sites for bioherm growth, in addition to exposing parts of the lower succession to erosion and karstification. Overall polarity of the basin switched as the eastern margin was elevated in the frontal thrusts of the Urals. The carbonate succession was terminated by increased clastic input from the advancing Ural orogen. 6 refs., 9 figs.

Zhemchugova, V.A. [Petroleum Scientific Research Geological Exploration Institute, Komi Republic (Russian Federation); Schamel, S. [Univ. of South Carolina, Columbia, SC (United States)

1994-01-01

 
 
 
 
21

Strontium and sulfur isotope study of well-preserved Permian anhydrite, Palo Duro basin, Texas  

International Nuclear Information System (INIS)

The ?34S, 87Sr/86Sr ratio, and strontium concentrations for 50 well-preserved samples of Permian marine anhydrite have been determined. The samples were collected from two continuous cores drilled through cyclic Permian evaporites, The Department of Energy drilled the samples in its search for a permanent storage facility for high-level nuclear waste. Primary depositional fabrics (selenite pseudomorphs) and high strontium concentrations (average 1,850 ppm), in association with published bromide and fluid inclusion data from associated halite, suggest primary seawater 87Sr/86Sr ratios may be recorded in many of the samples. The general shape of the 87Sr/86Sr ratio curve through the Permian is in accord with previously published observations. However, the increased stratigraphic detail from this unique set of cores constrains the abrupt charge in 87Sr/86Sr during the Permian at a precision previously available only in Deep Sea Drilling Project material. Interpretation of the more complex portions of the curve is limited by poor biostratigraphic control, the specter of provincial early diagenetic effects, and interpretation of the time significance of hiatal surfaces in cyclic strata. Age relationships are constrained by a K-Ar date on an interbedded volcanic ash in the Ochoan strata, and fusulinid age determinations of a well-documented regional transgression during the earliest Guadalupe. Sulfur isotopes yield typical Permian values of 12 per-thousand during the marine portion of the basin fill phase, and abruptly shift to 10 per-thousand in those cycles with a significant component of siliciclastic sediment

1990-01-01

22

Socioeconomic data base report for the Permian Basin  

International Nuclear Information System (INIS)

[en] This report presents the data base of socioeconomic characteristics of 14 counties and 13 key cities that surround the two locations in the Palo Duro Basin. The information describes the demographic features, economic base, community facilities and services, and governmental and fiscal structure. The land use patterns and zoning requirements for selected cities of varying sizes and complexities and the general social characteristics of the region as a whole are described also. Extensive references, 23 figures, 92 tables

1984-01-01

23

Porosity formation in deep-burial environment: overview, with examples, from Permian basin  

Energy Technology Data Exchange (ETDEWEB)

Porosity formation accompanying deep burial is ubiquitous and widespread in the Permian basin, particularly but not exclusively in offshore platform and resedimented basinal carbonates of Pennsylvanian and Permian age. Hydrocarbon reservoirs in such platform carbonate examples locally contain evidence of subaerial exposure and meteoric diagenesis. Commonly, much of the porosity formed during exposure is ultimately reduced by compaction and cementation during early burial. By contrast, no evidence of meteoric diagenesis is observed in associated basinal carbonates, although compaction and cementation accompanying progressive burial are readily evident. In both cases, however, such early diagenesis is overprinted by late burial dissolution, sometimes coincident with hydrocarbon emplacement, creating rocks of high porosity. The formation of porosity by cement dissolution may exhume occluded pores or enhance relict pores that formed in the eogenetic zone, the result being a preponderance of interparticle and moldic pores and residual cements that mimic vadose and phreatic products. In other cases, nonfabric selective dissolution, locally associated with fractures or stylolites, creates vuggy porosity which may resemble that formed during eodiagenesis. Multiple phases of deep-burial dissolution and partial cementation or replacement (by calcite or dolomite) are indicated for many of these diagenetic systems and result in a complex suite of different pore types.

Mazzullo, S.J.; Harris, P.M.

1989-03-01

24

Archaea dominate ammonia oxidizers in the permian water ecosystem of midland basin.  

UK PubMed Central (United Kingdom)

We investigated the existence and characteristics of ammonia oxidizers in Permian water from Midland Basin. Molecular surveys targeting the amoA gene showed that only ammonia-oxidizing archaea (AOA) exist and have potential activity in this special environment. In contrast, no ammonia-oxidizing bacteria (AOB) were detected in the water. Phylogenetic analysis indicated that 72-89% of the total screened AOA clones were affiliated with those found in underground water, and 10-24% of the AOA clones were related to those found in marine water or sediments. Our results indicate AOA might be the most abundant ammonia-oxidizing microbes in this ecological niche.

Hong Y; Youshao W; Chen F

2013-09-01

25

A paleomagnetic study of Permian and Triassic rocks from the Toulon-Cuers Basin, SE France: Evidence for intra-Pangea block rotations in the Permian  

Science.gov (United States)

The identification of a massive shear zone separating Gondwana from Laurasia during late Palaeozoic times is one of the prerequisites for the controversial Pangea B to A transition. Here we present new paleomagnetic data from Permian and Triassic sediments and volcanic rocks from the Toulon-Cuers basin, SE France, likely to be situated within this intra-Pangea shear zone. A total of 150 samples from 14 sites were collected in the field; 108 samples yielded reliable paleomagnetic component directions based on stepwise thermal demagnetization up to maximum temperatures of 690°C. After removal of an initial viscous magnetic component from room temperature up to 200°C, a second component of reverse polarity, oriented to the south-and-up, was identified in almost all samples of Permian age. The Triassic samples behave similarly, with the notable difference that here, two polarities of magnetization are present. Positive field tests suggest the primary character of this characteristic magnetization. The latitudes of the resulting Early to Mid Permian paleopoles agree well with the corresponding segment of the apparent polar wander path (APWP) for Europe, whereas the longitudes are strung out along a small circle segment, indicating relative rotations between the sampled regions and stable Europe. The Triassic poles, instead, plot close to the Triassic segment of the European APWP and provide an upper time limit for the observed rotations. These results suggest a wrench faulting event associated with intra-Pangea crustal instability and transformation during the Permian.

Aubele, K.; Bachtadse, V.; Muttoni, G.; Ronchi, A.; Durand, M.

2012-06-01

26

Isotope shifts in the late Permian of the Delaware Basin, Texas, precisely timed by varved sediments  

Energy Technology Data Exchange (ETDEWEB)

Closely spaced samples (285 in number) of varved sediments from the Upper Permian in Delaware Basin, Texas, have been analyzed for delta/sup 13/Csub(carb), delta/sup 13/Csub(org), delta/sup 18/Osub(carb), Csub(org), Csub(carb) and calcite/dolomite. delta/sup 13/C records a dramatic rise from -2.8 to + 5.7 per mille in only 4400 years, detected in three sections across the basin, extrapolating smoothly through a 600-year interruption by a local (west side of the basin) fresh-water inflow evidenced by low delta/sup 18/O. This continuity and low Csub(org) within the basin, both indicate that the excess net deposition of Csub(org), necessary to generate the rise in delta/sup 13/C, took place in the ocean external to the Delaware Basin, Correlation with similar records from the Zechstein Basin suggest that the event was world-wide, although this poses obvious difficulties for the carbon cycle. The rate of rise of delta/sup 13/C, and its sustained high level, must imply conversions of oxidized carbon to reduced carbon that are very large depending on which reservoirs were involved.

Magaritz, M. (Weizmann Inst. of Science, Rehovoth (Israel). Isotope Dept.; Oregon Univ., ugene (USA). Dept. of Geology); Anderson, R.Y. (New Mexico Univ., Albuquerque (USA). Dept. of Geology); Holser, W.T. (Oregon Univ., Eugene (USA). Dept. of Geology); Saltzmann, E.S. (Miami Univ., FL (USA). Rosenstiel School of Marine and Atmospheric Sciences); Garber, J. (Weizmann Inst. of Science, Rehovoth (Israel). Isotope Dept.)

1983-12-01

27

Geology and Permian coal resources of the Collie Basin, Western Australia  

Energy Technology Data Exchange (ETDEWEB)

The Collie Basin is a structure containing approximately 1200 m of generally southwesterly dipping Permian siliciclastics preserved as a consequence of right-lateral shear in a transtensional setting. Gravity and drilling data indicate the basin is 226 km{sup 2} in area and that it comprises two weakly folded grabens striking northwest. The coal-bearing section reaches a maximum thickness of 900 m, of which up to 74 m consist of coal in 60 principal seams between 0.5 and 1.3 m thick. Permian stratigraphy is revised. Significant tectonics in the Permian of Western Australia are inferred from vitrinite reflectance determinations, which indicate that maximum coal-burial depth approached 8 km. Collie coal resources total 2400 Mt. Approximately 37% of the coal lies in the current opencut mining window. Maximum vitrinite reflectance averages 0.43 in the Muja Coal Measures and 0.60 in the deeper Premier and Ewington Coal Measures. The coal rank is subbituminous in the Muja Coal Measures and bituminous in the Ewington and Premier Coal Measures. Tabulated qualities of Collier coal include proximate and specific energy, sulfur, ash fusion temperature, abrasiveness, hardgrove grindability, ultimate, ash, trace element, petrographic and maceral analyses. Coal is mined in four opencut and three underground mines by two companies. The Griffin Coal Mining Company Proprietary Limited and Western Collieries Limited. In the past 100 years over 100 Mt has been produced. About 79% of Collie coal is purchased by the State Energy Commission for power stations; the balance is used for private power generation, cement manufacture, brick making, mineral sands processing and other industrial applications. A demonstrated potential exists for alternative coal utilization technologies including direct reduction of metal ores. There are currently no coal exports. In a pocket with 8 folded plates. 173 refs., 46 figs., 12 tabs.

Le Blanc Smith, G.

1993-12-31

28

Total petroleum systems of the Bonaparte Gulf Basin area, Australia; Jurassic, Early Cretaceous-Mesozoic; Keyling, Hyland Bay-Permian; Milligans-Carboniferous, Permian  

Science.gov (United States)

The Bonaparte Gulf Basin Province (USGS #3910) of northern Australia contains three important hydrocarbon source-rock intervals. The oldest source-rock interval and associated reservoir rocks is the Milligans-Carboniferous, Permian petroleum system. This petroleum system is located at the southern end of Joseph Bonaparte Gulf and includes both onshore and offshore areas within a northwest to southeast trending Paleozoic rift that was initiated in the Devonian. The Milligans Formation is a Carboniferous marine shale that sources accumulations of both oil and gas in Carboniferous and Permian deltaic, marine shelf carbonate, and shallow to deep marine sandstones. The second petroleum system in the Paleozoic rift is the Keyling, Hyland Bay-Permian. Source rocks include Lower Permian Keyling Formation delta-plain coals and marginal marine shales combined with Upper Permian Hyland Bay Formation prodelta shales. These source-rock intervals provide gas and condensate for fluvial, deltaic, and shallow marine sandstone reservoirs primarily within several members of the Hyland Bay Formation. The Keyling, Hyland Bay-Permian petroleum system is located in the Joseph Bonaparte Gulf, north of the Milligans-Carboniferous, Permian petroleum system, and may extend northwest under the Vulcan graben sub-basin. The third and youngest petroleum system is the Jurassic, Early Cretaceous-Mesozoic system that is located seaward of Joseph Bonaparte Gulf on the Australian continental shelf, and trends southwest-northeast. Source-rock intervals in the Vulcan graben sub-basin include deltaic mudstones of the Middle Jurassic Plover Formation and organic-rich marine shales of the Upper Jurassic Vulcan Formation and Lower Cretaceous Echuca Shoals Formation. These intervals produce gas, oil, and condensate that accumulates in, shallow- to deep-marine sandstone reservoirs of the Challis and Vulcan Formations of Jurassic to Cretaceous age. Organic-rich, marginal marine claystones and coals of the Plover Formation (Lower to Upper Jurassic), combined with marine claystones of the Flamingo Group and Darwin Formation (Upper Jurassic to Lower Cretaceous) comprise the source rocks for the remaining area of the system. These claystones and coals source oil, gas, and condensate accumulations in reservoirs of continental to marine sandstones of the Plover Formation and Flamingo Group. Shales of the regionally distributed Lower Cretaceous Bathurst Island Group and intraformational shales act as seals for hydrocarbons trapped in anticlines and fault blocks, which are the major traps of the province. Production in the Bonaparte Gulf Basin Province began in 1986 using floating production facilities, and had been limited to three offshore fields located in the Vulcan graben sub-basin. Cumulative production from these fields totaled more than 124 million barrels of oil before the facilities were removed after production fell substantially in 1995. Production began in 1998 from three offshore wells in the Zone of Cooperation through floating production facilities. After forty years of exploration, a new infrastructure of pipelines and facilities are planned to tap already discovered offshore reserves and to support additional development.

Bishop, M. G.

1999-01-01

29

Implications of paleomagnetic results from the Permian Rodez basin for the late Variscan tectonics in the southern French massif Central.  

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A paleomagnetic study has been carried out on three sedimentary formations of the Permian Rodez basin in the southern France. Two of them yield paleomagnetic poles of Saxonian and Thuringian age showing counterclockwise rotation of moderate amplitude, during or after the Thuringian deposition. For t...

Diego-Orozco, Arturo; Chen, Yan; Henry, Bernard; Becq-Giraudon, Jean-François

30

Pre-Mesozoic basement of the SW Paris Basin (France): The structural pattern of the Stephano-permian basins revisited using combined seismic, aeromagnetic and gravimetric methods  

Science.gov (United States)

Stephano-permian basins are found in several rather small places in and around the present-day French Variscan basement. They are mostly considered as intramontane post-orogenic (Variscan) basins, developing in close relationships with crustal to lithospheric geological events (such as extensive strike-slip, exhumation of metamorphic rocks, and widespread magmatism). On the other hand, little is known about their occurrences under their post depositional sedimentary covers. This is for instance the case in the Paris Basin, where significant but scarce studies aimed to find their location under the Mesozoic sedimentary cover. There, the questions of their extension, thickness, sedimentary filling, internal geometry and structural control still remain open. In the same way, their differential conservation compared with the basins known in the field, or the possible structural decoupling between the pre-Mesozoic and Mesozoic units, has still to be debated. Our study addresses the Stephano-permian basins located in the south-western part of the Paris Basin. We use combined subsurface tools, such as boreholes, newly reprocessed seismic lines (about 1400 km length), recent high-resolution aeromagnetic surveys, and ground gravimetry data. Our main observations and results can be summarized as follow: (1) the Stephano-permian sedimentary sequences can reach thicknesses up to 2800 m; (2) the primary Stephano-permian structural signal is strongly disturbed by post Permian tectonic activity (polyphase and late strike-slip faults); the latter has therefore to be removed to get the former; (3) the sedimentation took place under 2 successive phases, with a clear structural control at the initiation of the basin, preceding a more diffuse subsidence pattern; (4) the map view of the structural pattern and the cartographic extension of the basins shows the predominant role of strike-slip structures during the sedimentation processes.

Beccaletto, Laurent; Lasseur, Eric; Martelet, Guillaume; Serrano, Olivier; Capar, Laure; Marc, Stéphane

2013-04-01

31

The achievement of the century. The petroleum geological atlas of the southern Permian basin is appeared; Das Jahrhundertwerk. Der erdoelgeologische Atlas des suedlichen Permbeckens ist erschienen  

Energy Technology Data Exchange (ETDEWEB)

The product impresses already by its dimensions: 12.3 kilograms in weight and in the format not smaller than a large flat screen: The atlas of petroleum geology of the southern Permian basin. But not only outwardly, but also internally the work has something to offer. In the atlas the knowledge from 150 years of industrial exploration activity and research in a region known as southern Permian basin or Central European basin is summarized. As the largest sediment basin of Europe it is a typical intracontinental basin which developed from the upper carbon to today and extends from East England to Belarus.

Doornenbal, Hans [TNO, Utrecht (Netherlands); Kosinowski, Michael; Pletsch, Thomas [Bundesanstalt fuer Geowissenschaften und Rohstoffe (BGR), Hannover (Germany)

2011-01-15

32

Dolomitization of coeval shelf and fore-shelf carbonates, Lower Permian, Midland basin, Texas  

Energy Technology Data Exchange (ETDEWEB)

Coeval shelf and fore-shelf carbonates in Lower Permian (Leonardian) rocks in the Midland basin are pervasively dolomitized. Shelf strata consist of a regional mosaic of shelf margin reef, lagoon, and peritidal facies associated with contemporaneous evaporite deposition; fore-shelf facies consist of resedimented shelf margin deposits. Numerous relative sea-level fluctuations that resulted in the formation of Type 1 and 2 unconformities are recognized throughout this section. Mean stable oxygen and carbon isotopic compositions of the shelf strate suggest that dolomitization occurred essentially syndepositionally, likely by interaction with normal marine( ) and hypersaline fluids. In fore-shelf strata petrographic evidence, in combination with paleotemperature estimates from isotopic data and the burial depth-temperature history of these rocks, suggest relatively early (late Permian) dolomitization in rock-dominated systems. Three possible modes of dolomitization could have affected these fore-shelf beds: (1) dolomitization by reflux of normal-marine and/or hypersaline fluids during sea level highstands or lowstands; (2) dolomitization by mixed meteoric-marine fluids during lowstands; and (3) replacement by calcic dolomites via reaction with circulating marine fluids during deposition and early, shallow burial without organic matter influences. The latter mode of origin, however, is favored for most of the rocks examined on the basis of the slightly positive carbon isotopic compositions, Sr versus MgCO{sub 3} compositions (mean Sr 61 ppm, mean MgCO{sub 3} 49.5), and low Mn contents (mean 61 ppm) of the dolomites, although later burial recrystallization is indicated by their relatively depleted isotopic compositions.

Mazzullo, S.J.; Qiuchang, Ye (Wichita State Univ., KS (United States))

1991-03-01

33

Origin, distribution, and movement of brine in the Permian Basin (U. S. A. ). A model for displacement of connate brine  

Energy Technology Data Exchange (ETDEWEB)

Na-Cl, halite Ca-Cl, and gypsum Ca-Cl brines with salinities from 45 to >300 g/L are identified and mapped in four hydrostratigraphic units in the Permian Basin area beneath western Texas and Oklahoma and eastern New Mexico, providing spatial and lithologic constraints on the interpretation of the origin and movement of brine. Na-Cl brine is derived from meteoric water as young as 5-10 Ma that dissolved anhydrite and halite, whereas Ca-Cl brine is interpreted to be ancient, modified-connate Permian brine that now is mixing with, and being displaced by, the Na-Cl brine. Displacement fronts appear as broad mixing zones with no significant salinity gradients. Evolution of Ca-Cl brine composition from ideal evaporated sea water is attributed to dolomitization and syndepositional recycling of halite and bittern salts by intermittent influx of fresh water and sea water. Halite Ca-Cl brine in the evaporite section in the northern part of the basin differs from gypsum Ca-Cl brine in the south-central part in salinity and Na/Cl ratio and reflects segregation between halite- and gypsum-precipitating lagoons during the Permian. Ca-Cl brine moved downward through the evaporite section into the underlying Lower Permian and Pennsylvanian marine section that is now the deep-basin brine aquifer, mixing there with pre-existing sea water. Buoyancy-driven convection of brine dominated local flow for most of basin history, with regional advection governed by topographically related forces dominant only for the past 5 to 10 Ma. 71 refs., 11 figs.

Bein, A.; Dutton, A.R. (Univ. of Texas, Austin (United States))

1993-06-01

34

Late orogenic magmatism and sedimentation within Late Carboniferous to Early Permian basins in the Balkan terrane (Bulgaria): geodynamic implications  

Science.gov (United States)

The orogenic Balkanid belt, which developed between the Moesian Plate and the Moravian-Rhodopi-Thracian Massifs, was affected by the Late Carboniferous and Early Permian opening of W-E oriented graben structures. The progressive tectonic rejuvenation of the basins is demonstrated by the deposition of repeated regional sedimentary cycles, associated with volcanism that was mostly localised along the tectonic boundaries, in an intramontane setting.

Cortesogno, Luciano; Gaggero, Laura; Ronchi, Ausonio; Yanev, Slavcho

2004-09-01

35

Charcoal remains from a tonstein layer in the Faxinal Coalfield, Lower Permian, southern Paraná Basin, Brazil  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Charcoal fóssil foi encontrado na Mina do Faxinal, Permiano Inferior, Formação Rio Bonito, na porção sul da Bacia do Paraná, Brasil. Foram descritos três tipos de lenhos gimnospérmicos picnoxílicos originários de um único nível de tonstein, o que confirma a ocorrência de paleoincêndios vegetacionais nesta área. Uma redução da concentração de charcoal da base para o topo no nível de tonstein indica que a quantidade de combustível diminuiu durante a dep (more) osição, provavelmente devido ao consumo da vegetação existente pelo fogo. A presença de inertinita na camada de carvão, em níveis sobrepostos e sotopostos ao tonstein , indica que incêndios não estavam restritos ao intervalo de deposição da cinza vulcânica. A integração dos novos dados aqui apresentados com outros publicados anteriormente acerca da Mina do Faxinal, demonstra que eventos vulcânicos ocorridos nas áreas circunvizinhas podem ser identificados como potenciais fatores de ignição para os incêndios. A presença de chacoal em sedimentos associados a níveis de carvão em diferentes localidades no Permiano, demonstra que incêndios vegetacionais foram relativamente comuns nos ambientes formadores dos depósitos de carvão da Bacia do Paraná. Abstract in english Fossil charcoal has been discovered in the Faxinal Coalfield, Early Permian, Rio Bonito Formation, in the southernmost portion of the Paraná Basin, Brazil. Three types of pycnoxylic gymnosperm woods recovered from a single tonstein layer are described and confirm the occurrence of paleowildfire in this area. A decrease of the charcoal concentration from the base to the top within the tonstein layer indicates that the amount of fuel declined during the deposition probably (more) due to the consumption of vegetation by the fire. The presence of inertinite in coals overlying and underlying the tonstein layer indicates that fire-events were not restricted to the ash fall interval. The integration of the new data presented in the current study with previously published data for the Faxinal Coalfield demonstrates that volcanic events that occurred in the surrounding areas can be identified as one potential source of ignition for the wildfires. The presence of charcoal in Permian sediments associated with coal levels at different localities demonstrates that wildfires have been relatively common events in the peat-forming environments in which the coal formation took place in the Paraná Basin.

Jasper, André; Uhl, Dieter; Guerra-Sommer, Margot; Abu Hamad, Abdalla M. B; Machado, Neli T. G

2011-06-01

36

High precision radiometric ages from the northern Sydney Basin and their implication for the Permian time interval and sedimentation rates  

International Nuclear Information System (INIS)

[en] Three pyroclastic samples that bracket the coal-bearing Permian System of the northern Sydney Basin have been dated using the zircon U/Pb and hornblende K/Ar methods. The Matthews Gap Dacitic Tuff Member, situated 170 m below the base of the Permian System, gives a best estimate of 309 ± 3 Ma. Its age correlates well with the Paterson Volcanics which suggests that the immediately overlying clastic sediments are equivalent to the Seaham Formation. The Awaba Tuff, which is located 50 m below the top of the Permian System, gives a best estimate of 256 ± 4 Ma. An intervening horizon, the Thornton Claystone of the Tomago Coal Measures, gives a best estimate of 266 ± 0.4 Ma. The ages indicate an earlier beginning ? 299 Ma BP), an earlier termination (? 255 Ma BP) and slightly longer duration (44±13 Ma) of the Permian System in the Hunter Valley than previously suggested. Sedimentation rates of ± 65m/Ma, calculated from proximal sequence thicknesses, are only half the rate calculated from the closest maximum thicknesses. Both are considerably lower than previously quoted rates. The estimated time interval of 10 Ma between the Thornton Claystone and the Awaba Tuff is more than twice the length of time previously attributed to accumulation of the combined Tomago and Newcastle Coal Measures. 38 refs., 5 tabs., 2 figs

1990-01-01

37

Evidence of a therapsid scavenger in the Late Permian Karoo Basin, South Africa  

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Full Text Available Dicynodonts are an extinct group of herbivorous non-mammalian therapsids (‘mammal-like’ reptiles) that are widely known from terrestrial Permo-Triassic strata throughout Pangaea. Dicynodont fossil remains are common within the Late Permian Beaufort Group of the Karoo Basin in South Africa. A large, partially articulated dicynodont skeleton recovered from the TropidostomaAssemblage Zone is taphonomically important in having an unusual disarticulation pattern, bone surface punctures and a broken tooth of an unidentified carnivore associated with it. Here we report on the nature of the bone damage, and the identity of the carnivore that lost a canine tooth whilst scavenging the dicynodont carcass. The morphological characteristics of the serrations on the unidentified tooth were compared with those of contemporaneous carnivores, the gorgonopsians and therocephalians. Scanning electron microscopy analysis of a silicone cast of the unidentified tooth revealed distinctive 0.5-mm square-shaped serrations. Our comparative assessment of the tooth size, curvature, cross-sectional shape and morphology of the serrations revealed that the unidentified canine most closely matched Aelurognathus,a gorgonopsian known from the same assemblage zone.

Nicholas Fordyce; Roger Smith; Anusuya Chinsamy

2012-01-01

38

Evidence of a therapsid scavenger in the Late Permian Karoo Basin, South Africa  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english Dicynodonts are an extinct group of herbivorous non-mammalian therapsids ('mammal-like' reptiles) that are widely known from terrestrial Permo-Triassic strata throughout Pangaea. Dicynodont fossil remains are common within the Late Permian Beaufort Group of the Karoo Basin in South Africa. A large, partially articulated dicynodont skeleton recovered from the Tropidostoma Assemblage Zone is taphonomically important in having an unusual disarticulation pattern, bone surface (more) punctures and a broken tooth of an unidentified carnivore associated with it. Here we report on the nature of the bone damage, and the identity of the carnivore that lost a canine tooth whilst scavenging the dicynodont carcass. The morphological characteristics of the serrations on the unidentified tooth were compared with those of contemporaneous carnivores, the gorgonopsians and therocephalians. Scanning electron microscopy analysis of a silicone cast of the unidentified tooth revealed distinctive 0.5-mm square-shaped serrations. Our comparative assessment of the tooth size, curvature, cross-sectional shape and morphology of the serrations revealed that the unidentified canine most closely matched Aelurognathus, a gorgonopsian known from the same assemblage zone.

Fordyce, Nicholas; Smith, Roger; Chinsamy, Anusuya

2012-01-01

39

McElroy field: Development of a dolomite reservoir, Permian Basin of west Texas  

Energy Technology Data Exchange (ETDEWEB)

McElroy field, located in west Texas along the boundary between Crane and Upton Counties, lies along the eastern edge of the Central Basin platform. Production is from the Permian Grayburg Formation. The structure of the reservoir in McElroy field is a north-south-trending asymmetrical anticline with a steep east flank and gently dipping west flank. A stratigraphic permeability barrier defines the western boundary of the field, whereas the eastern edge of the reservoir is limited by a gradual reduction of permeability coupled with an increase in water saturation. Wells in McElroy field range in depth from 3,000 to 4,100 ft and produce from a gross section that averages 275 ft in thickness. Average reservoir porosity is 14% with permeability ranging from 0.01 to 2,000 md. Total areal extent of the field exceeds 50 mi{sup 2}. Since the field was discovered in 1926, more than 1,800 wells have been drilled. Secondary recovery processing of the reservoir began in 1960.

Walker, S.D.; Harris, P.M. (Chevron U.S.A., Midland, TX)

1987-02-01

40

Petrology of the Permian coal, Cardiff Sub-basin, Collie Basin, Western Australia. [Australia - Western Australia  

Energy Technology Data Exchange (ETDEWEB)

The coal types and maceral composition of coal from the Cardiff Sub-basin, and the plant fossils in the interseam sediments reflect the formation of peat from woody vegetation (pteridophytes). The higher content of inertodetrinite represents fluctuating water table in the water logged ecosystems. 6 refs., 4 figs.

Sappal, K.K. (Curtin University of Technology, Perth, WA (Australia))

1989-10-01

 
 
 
 
41

Pumping test and fluid sampling report, Mansfield No. 1 well, Palo Duro Basin: Report of the Geologic Project Manager, Permian Basin  

Energy Technology Data Exchange (ETDEWEB)

This report describes pumping test and fluid sampling activities performed at the Mansfield No. 1 well in Oldham County about 10 miles north of Vega, Texas. The well site was selected by TBEG and is located along the northern margin of the Palo Duro Basin in an area of active dissolution with the Permian salt sections. The objectives of the pumping test and fluid sampling program were to collect data to determine the hydrologic characteristics (formation pressure and permeability) of deep water bearing formations, and to obtain formation fluid samples for analyses (gas and fluid chemistry) in order to evaluate fluid migration and age relationships in the Permian Basin. 4 refs., 8 figs., 2 tabs.

1983-07-01

42

Pumping test and fluid sampling report, Mansfield No. 1 well, Palo Duro Basin: Report of the Geologic Project Manager, Permian Basin  

International Nuclear Information System (INIS)

[en] This report describes pumping test and fluid sampling activities performed at the Mansfield No. 1 well in Oldham County about 10 miles north of Vega, Texas. The well site was selected by TBEG and is located along the northern margin of the Palo Duro Basin in an area of active dissolution with the Permian salt sections. The objectives of the pumping test and fluid sampling program were to collect data to determine the hydrologic characteristics (formation pressure and permeability) of deep water bearing formations, and to obtain formation fluid samples for analyses (gas and fluid chemistry) in order to evaluate fluid migration and age relationships in the Permian Basin. 4 refs., 8 figs., 2 tabs

1983-01-01

43

Geochemistry of post-uplift calcite in the Permian Basin of Texas and New Mexico  

Energy Technology Data Exchange (ETDEWEB)

Integration whole-oil gas chromatography of produced oil and oil inclusions, formation-water chemistry, and stable isotopes has identified environment-diagnostic differences in calcite cements between oil field and outcrop environments in the Permian Basin of Texas and New Mexico. Calcite-[delta][sup 13]C and fluid-inclusion composition are the most diagnostic of pore-fluid evolution and can help interpret rock-fluid reactions. Late-stage calcite cement in the northwestern part of the basin formed in a meteoric aquifer that was emplaced by Neogene-age uplift and tilting of the Guadalupe Mountains. Where the confined aquifer intersects the Henderson oil field, the water, which is less saline than sea water, has 900-1,400 ppm bicarbonate alkalinity because of oil oxidation and contains 750 ppm H[sub 2]S as a result of anhydrite calcitization and sulfate reduction. The oil field has been severly damaged by biodegradation. Modeling of [delta][sup 13]C in pore-filling calcite from the field (mean [delta][sup 13]C = [minus]17% PDB) suggests oxidation of oil provided nearly 100% of the carbon in the cement. Comparison of gas chromatograms of produced oil and oil liberated from fluid inclusions in calcite shows that inclusion oil is older and more severely biodegraded (paraffin-free) than produced oil. This implies that oil in the reservoir was remobilized soon after Neogene-age meteoric invasion and carbonate cementation. The Algerita Escarpment in the Guadalupe Mountains is the site of active meteoric water recharge and growth of phreatic calcite cement. The phreatic cement contains single-phase, aqueous fluid inclusions. The cement is depleted in [sup 13]C to an extent that is diagnostic of a 1:1 mixture of soil-CO[sub 2] from decay of C[sub 4]-type plants (desert grasses) and carbon derived from dolomite matrix by ground-water dissolution. 64 refs., 12 figs., 3 tabs.

Wiggins, W.D.; Harris, P.M. (Chevron Oil Field Research Company, La Habra, CA (United States)); Burruss, R.C. (Geological Survey, Denver, CO (United States))

1993-06-01

44

Natural gas qualities in the Southern Permian basin; Die Erdgasqualitaeten im suedlichen Permbecken  

Energy Technology Data Exchange (ETDEWEB)

There is a substantial amount of molecular and isotopic gas data in the literature but mostly in the archives of companies and geological services. As the geological services of most European countries traditionally contain (confidential and non-confidential) data on geology and resources these institutions from Great Britain, the Netherlands, Denmark, Poland and Germany decided to compile molecular and isotopic natural gas data from the area of the Southern European Permian basin. The partially EU-subsidised project was carried out between 1994 and 1997 (LOKHORST ed. 1998) The atlas is based on existing data and also on newly determined molecular and isotopic gas parameters. Ring analyses of national and international standard gases ensure the quality and comparability of the data thus obtained. The aim of the ``stocktaking`` of natural gas was to describe the gas qualities from the Southern North Sea in the West to the Eastern borders of Poland, to characterise them genetically and to relate the to the geological environment. (orig.) [Deutsch] Ein substantieller Anteil von molekularen und isotopischen Gasdaten existiert, teilweise in der Literatur, vor allem aber in den Archiven der Firmen und der geologischen Dienste. Da die geologischen Dienste der meisten europaeischen Laender traditionell (oeffentliche und vertrauliche) Daten ueber die Geologie und Rohstoffe vorhalten, haben sich diese Institutionen aus Grossbritanien, den Niederlanden, Daenemark, Polen und Deutschlands entschlossen, molekulare und isotopische Erdgasdaten aus dem Bereich des suedlichen europaeischen Permbeckens zu kompilieren. Das partiell von der EU gefoerderte Projekt wurde in den Jahren 1994 bis 1997 durchgefuehrt (LOKHORST ed. 1998). Ausser auf bereits vorhandenen Daten beruht der Atlas auf etwa 200 Neu-Bestimmungen molekularer und isotopischer Gasparameter. Ringanalysen nationaler und internationeler Standardgase gewaehrleisteten die Qualitaet und die Vergleichbarkeit der gewonnenen Daten. Ziele dieser `Erdgas-Inventur` waren, die Gasqualitaeten in ihrer raeumlichen Verteilung von der suedlichen Nordsee im Westen bis nahezu an die Ostgrenze Polens darzustellen, sie genetisch zu charakterisieren und eine Beziehung zu den geologischen Rahmenbedingungen herzustellen. (orig.)

Gerling, P.; Kockel, F. [BGR, Hannover (Germany); Lokhorst, A.; Geluk, M.C. [TNO, Haarlem (Netherlands); Nicholson, R.A. [British Geological Survey, Nottingham (United Kingdom); Laier, T. [Danmarks og Groenlands Geologiske Undersoegelse, Kopenhagen (Denmark); Pokorski, J. [Panstwowy Instytut Geologiczny, Warsaw (Poland)

1998-12-31

45

Thermal properties of Permian Basin evaporites to 493 K temperature and 30 MPa confining pressure  

International Nuclear Information System (INIS)

Laboratory measurements of the thermal conductivity and diffusivity of four rock salts, two anhydrites, and two dolomites bordering Cycle 4 and Cycle 5 bedded salt formations in the Permian Basin in Deaf Smith County, Texas, were made in conditions ranging from 303 to 473 K in temperature and 0.1 to 31.0 MPa in hydrostatic confining pressure. Within the +-5% measurement resolution neither conductivity nor diffusivity showed a dependence upon pressure in any of the rocks. Conductivity and diffusivity in all rocks had a negative temperature dependence. For the Cycle 4 salt samples, conductivity fell from 5.5 to 3.75 W/m . K, and diffusivity fell from about 2.7 to 1.7 x 10-6 m2/s. One Cycle 5 salt was a single crystal with anomalous results, but the other had a low conductivity with very weak temperature dependence and a high diffusivity. In the nonsalts, conductivity and diffusivity decreased 10 to 20% over the temperature range explored. In measurements of the coefficient of thermal linear expansion for Cycle 5 salt and nonsalts, the coefficient typically varied from about 12 x 10-6 K-1 at P = 3.0 MPa to 4 x 10-6 K-1 at P = 30 MPa for both nonsalt rocks. In anhydrite, it decreased with increasing temperature. In dolomite, the coefficient increased at roughly the same rate. Expansion of the salt ranged from 33 to 38 x 10-6 K-1 and was independent of pressure and temperature

1987-01-01

46

Diagenesis and reservoir potential of Permian-Triassic fluvial/lacustrine sandstones in the southern Junggar basin, northwestern China  

Energy Technology Data Exchange (ETDEWEB)

The Junggar basin is one of the largest oil-producing areas in China, and contains Upper Permian lacustrine oil shales with some of the greatest hydrocarbon potential in the world. In this study, we present the diagenetic characteristics of Permian-Triassic sandstones from the southern Junggar basin and evaluate their reservoir potential. The uppermost Permian and Lower Triassic Cangfanggou Group in the southern Junggar basin is characterized by alternating fluvial and lacustrine deposits, whereas the Middle-upper Triassic Xiaoquangou Group was deposited predominantly in a lacustrine environment; fluvial and deltaic sedimentation was subordinate. The sandstones of the Cangfanggou and Xiaoquangou groups are volcanic litharenites. Their detrital modes and textures of volcanic fragments suggest a primarily andesitic/basaltic volcanic-arc provenance. Early diagenesis of the sandstones is characterized by nonferroan calcite cementation, grain-coating, pore-lining clay minerals, and the initial dissolution of detrital grains. Authigenic quartz; pore-filling phyllosilicates; pore-filling, grain-replacive zeolites; albitized detrital plagioclase; authigenic K-feldspar; illite; and late calcite dominate burial diagenesis. The formation of iron oxides and dissolution of calcite cement resulted from tectonic uplift during the Tertiary. Albitization and zeolite formation during burial are among the most pronounced diagenetic processes that affected these sandstones. Pore-filling clay minerals, calcite, and zeolites have substantially reduced sandstone porosity. However, appreciable primary porosity has been preserved by the formation of early clay coats and pore linings, which retarded further cementation. Secondary porosity is present to varying degrees in the sandstones and is the result of dissolution of unstable framework grains.

Tang, Zhaohui; Longstaffe, F.J. [Univ. of Western Ontario, London (Canada); Parnell, J. [Queen`s Univ. of Belfast (United Kingdom)

1997-11-01

47

Petrographic composition and sulphur content of coals associated with alluvial fans in the Permian Sydney and Gunnedah Basins, eastern Australia  

Energy Technology Data Exchange (ETDEWEB)

The Sydney and Gunnedah Basins, which formed during the Permian on the eastern margin of Australia, contain restricted marine and terrestrial sediments deposited during two transgressive-regressive cycles. The progradational and aggradational regressive successions include back-barrier, prodelta, lower delta plain, upper delta plain and braided fluvial facies of alluvial-fan systems, the proportion of coarse clastics increasing eastward toward the orogenic hinterland. Coals associated with a 1000 m thick sequence of alluvial-fan dominated sediments deposited during the Early Permian in the Gunnedah Basin are generally vitrinite-rich (75% mmf), with mainly structured inertinite (semifusinite) and low sulphur contents (less than 0.55% daf). The coals were formed from a woody peat facies under consistently high water-table conditions, with access to terrestrial sulphate only. Coals associated with alluvial fans and associated fluvial and deltaic systems deposited during the Late Permian in the Sydney Basin consist of high vitrinite (65% mmf), low to medium sulphur (less than 1.0% daf) seams in the distal facies, and low to high vitrinite (35-65% mmf), low sulphur (less than 0.55% daf) seams in the more proximal facies. Semifusinite is the dominant inertinite in both facies, and the seams were formed from a woody peat. The progressively lower water-table levels and decreasing vitrinite content up the sequence are probably the result of eustatic control and increasing topographic elevation above the water-table. In coals associated with the upper delta plain and fluvial facies, sulphur is mainly organically bound (70-100%), and the proportion of pyritic sulphur increases to greater than 50% in the lower delta plain facies. 56 references.

Hunt, J.W.; Hobday, D.K.

1984-01-01

48

Regional summary and recommended study areas for the Texas panhandle portion of the Permian Basin. Technical report  

International Nuclear Information System (INIS)

This report summarizes the regional geologic and environmental characterizations that have been completed for the Permian region of study, and describes the procedure used to identify study areas for the next phase of investigation. The factors evaluated in the Permian region fall into three broad areas: health and safety, environmental and socioeconomic, and engineering and economic considerations. Health and safety considerations included salt depth and thickness, faults, seismic activity, groundwater, salt dissolution, energy and mineral resources, presence of boreholes, and interactive land uses. Salt depth and thickness was the key health and safety factor, and when mapped, proved to be a discriminator. The evaluation of environmental and socioeconomic conditions focused primarily on the presence of urban areas and on designated land uses such as parks, wildlife areas, and historic sites. Engineering and economic considerations centered primarily on salt depth, which was already evaluated in the health and safety area. The Palo Duro and Dalhart basins are recommended for future studies on the basis of geology. In these two basins, salt depth and thickness appear promising, and there is less likelihood of past or future oil and gas exploratory holes. Environmental and socioeconomic factors did not preclude any of the basins from further study

1979-01-01

49

OIL RESERVOIR CHARACTERIZATION AND CO2 INJECTION MONITORING IN THE PERMIAN BASIN WITH CROSSWELL ELECTROMAGNETIC IMAGING  

Energy Technology Data Exchange (ETDEWEB)

Substantial petroleum reserves exist in US oil fields that cannot be produced economically, at current prices, unless improvements in technology are forthcoming. Recovery of these reserves is vital to US economic and security interests as it lessens our dependence on foreign sources and keeps our domestic petroleum industry vital. Several new technologies have emerged that may improve the situation. The first is a series of new flooding techniques to re-pressurize reservoirs and improve the recovery. Of these the most promising is miscible CO{sub 2} flooding, which has been used in several US petroleum basins. The second is the emergence of new monitoring technologies to track and help manage this injection. One of the major players in here is crosswell electromagnetics, which has a proven sensitivity to reservoir fluids. In this project, we are applying the crosswell EM technology to a CO{sub 2} flood in the Permian Basin oil fields of New Mexico. With our partner ChevronTexaco, we are testing the suitability of using EM for tracking the flow of injected CO{sub 2} through the San Andreas reservoir in the Vacuum field in New Mexico. The project consisted of three phases, the first of which was a preliminary field test at Vacuum, where a prototype system was tested in oil field conditions including widely spaced wells with steel casing. The results, although useful, demonstrated that the older technology was not suitable for practical deployment. In the second phase of the project, we developed a much more powerful and robust field system capable of collecting and interpreting field data through steel-cased wells. The final phase of the project involved applying this system in field tests in the US and overseas. Results for tests in steam and water floods showed remarkable capability to image between steel wells and provided images that helped understand the geology and ongoing flood and helped better manage the field. The future of this technology is indeed bright with development ongoing and a commercialization plan in place. We expect that this DOE sponsored technology will be a major technical and commercial success story in the coming years.

Michael Wilt

2004-02-01

50

Geoscience/Engineering Characterization of the Interwell Environment in Carbonate Reservoirs Based on Outcrop Analogs, Permian Basin, West Texas and New Mexico.  

Energy Technology Data Exchange (ETDEWEB)

The objective of this project is to investigate styles of reservoir heterogeneity found in low permeability pelleted wackestone/packstone facies and mixed carbonate/clastic facies found in Permian Basin reservoirs by studying similar facies found in Permian Basin reservoirs by studying similar facies exposed in the Guadalupe Mountains. Specific objectives for the outcrop study include construction of a stratigraphic framework, petrophysical quantification of the framework, and testing the outcrop reservoir model for effects of reservoir heterogeneity on production performance. Specific objectives for the subsurface study parallel objectives for the outcrop study.

Lucia, F.J.; Kerans, C.

1997-05-29

51

Regulatory Project Manager for Salina and Permian Basins for the NWTS [National Waste Terminal Storage] Program: Final techical report  

International Nuclear Information System (INIS)

The identification of candidate sites for nuclear waste repositories involves geological and environmental studies to characterize potential sites. These investigations include the collection and analysis of detailed geological and environmental data and comparison of the data against predetermined site performance criteria, i.e., geologic characteristics, environmental protection, and socioeconomic impacts. The work summarized in this final technical report encompasses mainly ''environmental characterization'' studies in the Permian Basin in the Texas Panhandle during the period of 1977-86; in the earlier phase of the contract, regional environmental work was also done in the Salina Basin (1977-79) and certain licensing support activities and safety analyses were conducted (1977-82). Considerable regulatory support work was also performed during 1986. 9 figs., 2 tabs.

1986-01-01

52

PLAY ANALYSIS AND DIGITAL PORTFOLIO OF MAJOR OIL RESERVOIRS IN THE PERMIAN BASIN: APPLICATION AND TRANSFER OF ADVANCED GEOLOGICAL AND ENGINEERING TECHNOLOGIES FOR INCREMENTAL PRODUCTION OPPORTUNITIES  

Energy Technology Data Exchange (ETDEWEB)

A play portfolio is being constructed for the Permian Basin in west Texas and southeast New Mexico, the largest petroleum-producing basin in the US. Approximately 1300 reservoirs in the Permian Basin have been identified as having cumulative production greater than 1 MMbbl of oil through 2000. Of these major reservoirs, approximately 1,000 are in Texas and 300 in New Mexico. On a preliminary basis, 32 geologic plays have been defined for Permian Basin oil reservoirs and assignment of each of the 1300 major reservoirs to a play has begun. The reservoirs are being mapped and compiled in a Geographic Information System (GIS) by play. Detailed studies of three reservoirs are in progress: Kelly-Snyder (SACROC unit) in the Pennsylvanian and Lower Permian Horseshoe Atoll Carbonate play, Fullerton in the Leonardian Restricted Platform Carbonate play, and Barnhart (Ellenburger) in the Ellenburger Selectively Dolomitized Ramp Carbonate play. For each of these detailed reservoir studies, technologies for further, economically viable exploitation are being investigated.

Shirley P. Dutton; Eugene M. Kim; Ronald F. Broadhead; William Raatz; Cari Breton; Stephen C. Ruppel; Charles Kerans; Mark H. Holtz

2003-04-01

53

A synthesis of palynological data from the Lower Permian Cerro Pelado Formation (Parana Basin, Uruguay): A record of warmer climate stages during Gondwana glaciations  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper presents a synthesis of the palynological record in the Cerro Pelado Formation deposits (Lower Permian, Paraná basin, Cerro Largo Department, north-eastern Uruguay) based on pre-existing data and new findings. The successions studied in this formation consist mainly of non-marine to glaci...

Beri, A.

54

Integrated Synthesis of the Permian Basin: Data and Models for Recovering Existing and Undiscovered Oil Resources from the Largest Oil-Bearing Basin in the U.S.  

Energy Technology Data Exchange (ETDEWEB)

Large volumes of oil and gas remain in the mature basins of North America. This is nowhere more true than in the Permian Basin of Texas and New Mexico. A critical barrier to recovery of this vast remaining resource, however, is information. Access to accurate geological data and analyses of the controls of hydrocarbon distribution is the key to the knowledge base as well as the incentives needed by oil and gas companies. The goals of this project were to collect, analyze, synthesize, and deliver to industry and the public fundamental information and data on the geology of oil and gas systems in the Permian Basin. This was accomplished in two ways. First we gathered all available data, organized it, and placed it on the web for ready access. Data include core analysis data, lists of pertinent published reports, lists of available cores, type logs, and selected PowerPoint presentations. We also created interpretive data such as type logs, geological cross sections, and geological maps and placed them in a geospatially-registered framework in ARC/GIS. Second, we created new written syntheses of selected reservoir plays in the Permian basin. Although only 8 plays were targeted for detailed analysis in the project proposal to DOE, 14 were completed. These include Ellenburger, Simpson, Montoya, Fusselman, Wristen, Thirtyone, Mississippian, Morrow, Atoka, Strawn, Canyon/Cisco, Wolfcamp, Artesia Group, and Delaware Mountain Group. These fully illustrated reports include critical summaries of published literature integrated with new unpublished research conducted during the project. As such these reports provide the most up-to-date analysis of the geological controls on reservoir development available. All reports are available for download on the project website and are also included in this final report. As stated in our proposal, technology transfer is perhaps the most important component of the project. In addition to providing direct access to data and reports through the web, we published 29 papers dealing with aspects of Permian Basin and Fort Worth Basin Paleozoic geology, and gave 35 oral and poster presentations at professional society meetings, and 116 oral and poster presentations at 10 project workshops, field trips, and short courses. These events were attended by hundreds of scientists and engineers representing dozens of oil and gas companies. This project and the data and interpretations that have resulted from it will serve industry, academic, and public needs for decades to come. It will be especially valuable to oil and gas companies in helping to better identify opportunities for development and exploration and reducing risk. The website will be continually added to and updated as additional data and information become available making it a long term source of key information for all interested in better understanding the Permian Basin.

John Jackson; Katherine Jackson

2008-09-30

55

Ichnological analysis in San Gregorio deposits (Lower Permian) in the Guazunambi hills area Uruguayan north basin  

International Nuclear Information System (INIS)

Ichnological analysis in deposits corresponding to San Gregorio Fm.(lower Permian) in the Guazunambi hills area (Cerro Largo Department, Uruguay) was made.Trace fossils in sandstones and mud stones outcrops were studied.The ichnofossil assemblage studied allows to propose a shallow marine environment. (author)

1998-01-01

56

Depositional cyclicity and paleoecological variability in an outcrop of Rio Bonito Formation, Early Permian, Parana Basin, Rio Grande do Sul, Brazil  

Energy Technology Data Exchange (ETDEWEB)

This article integrates faciological, paleobotanical, and palynological analyses to establish the relationship between depositional cyclicity and paleoecological patterns for the (Early Permian) Quiteria outcrop, Rio Bonito Formation, southern Parana Basin, Rio Grande do Sul state. The record in some coal palynofloras of Striadopodocarpites fusus, a component of the Hamiapollenites karrooensis subzone, as defined in the palynostratigraphic framework for the Parana Basin, indicates a Kungurian age for the palynoflora.

Jasper, A.; Menegat, R.; Guerra-Sommer, M.; Cazzulo-Klepzig, M.; de Souza, P.A. [UNIVATES, Lajeado (Brazil)

2006-07-15

57

Play Analysis and Digital Portfolio of Major Oil Reservoirs in the Permian Basin: Application and Transfer of Advanced Geological and Engineering Technologies for Incremental Production Opportunities  

Energy Technology Data Exchange (ETDEWEB)

A play portfolio is being constructed for the Permian Basin in west Texas and southeast New Mexico, the largest onshore petroleum-producing basin in the United States. Approximately 1,300 reservoirs in the Permian Basin have been identified as having cumulative production greater than 1 MMbbl (1.59 x 10{sup 5} m{sup 3}) of oil through 2000. Of these significant-sized reservoirs, approximately 1,000 are in Texas and 300 in New Mexico. There are 32 geologic plays that have been defined for Permian Basin oil reservoirs, and each of the 1,300 major reservoirs was assigned to a play. The reservoirs were mapped and compiled in a Geographic Information System (GIS) by play. The final reservoir shapefile for each play contains the geographic location of each reservoir. Associated reservoir information within the linked data tables includes RRC reservoir number and district (Texas only), official field and reservoir name, year reservoir was discovered, depth to top of the reservoir, production in 2000, and cumulative production through 2000. Some tables also list subplays. Play boundaries were drawn for each play; the boundaries include areas where fields in that play occur but are smaller than 1 MMbbl (1.59 x 10{sup 5} m{sup 3}) of cumulative production. Oil production from the reservoirs in the Permian Basin having cumulative production of >1 MMbbl (1.59 x 10{sup 5} m{sup 3}) was 301.4 MMbbl (4.79 x 10{sup 7} m{sup 3}) in 2000. Cumulative Permian Basin production through 2000 was 28.9 Bbbl (4.59 x 10{sup 9} m{sup 3}). The top four plays in cumulative production are the Northwest Shelf San Andres Platform Carbonate play (3.97 Bbbl [6.31 x 10{sup 8} m{sup 3}]), the Leonard Restricted Platform Carbonate play (3.30 Bbbl [5.25 x 10{sup 8} m{sup 3}]), the Pennsylvanian and Lower Permian Horseshoe Atoll Carbonate play (2.70 Bbbl [4.29 x 10{sup 8} m{sup 3}]), and the San Andres Platform Carbonate play (2.15 Bbbl [3.42 x 10{sup 8} m{sup 3}]). Detailed studies of three reservoirs are in progress: Kelly-Snyder (SACROC unit) in the Pennsylvanian and Lower Permian Horseshoe Atoll Carbonate play, Fullerton in the Leonard Restricted Platform Carbonate play, and Barnhart (Ellenburger) in the Ellenburger Selectively Dolomitized Ramp Carbonate play. For each of these detailed reservoir studies, technologies for further, economically viable exploitation are being investigated.

Shirley P. Dutton; Eugene M. Kim; Ronald F. Broadhead; Caroline L. Breton; William D. Raatz; Stephen C. Ruppel; Charles Kerans

2004-01-13

58

Petrography and aliphatic hydrocarbon composition of the Barrett Coal Member, Upper Permian Wittingham Coal Measures, northern Sydney Basin  

Energy Technology Data Exchange (ETDEWEB)

The Barrett Coal Member in the Howick Opencut Mine, Hunter Valley, NSW, is a high-volatile bituminous coal that forms the basal seam of the Upper Permian Foybrook Formation of the Wittingham Coal Measures in the Howick area. Detailed petrographic analyses of the coal reveal cycles of peat formation defined by variations in the ratio: structured vitrinite/unstructured vitrinite (= Tissue Preservation Index, or TPI); and the percentage of liptinite macerals. These cycles also correspond to coal plies that are separated invariably by dirtbands. The n-alkane distribution of the aliphatic hydrocarbon fraction of the Barrett Coal Extracts are similar to other analysed coals of the Sydney Basin, the Lower Carboniferous coals from Nigeria and the Permian East Bokaro coals of India, suggesting commonality of n-alkane distributions for Gondwanan coals of similar rank and depositional setting. The petrographic cyclicity of the Barrett Coal is also manifested by a corresponding stratigraphic cyclicity in the biomarker composition of the aliphatic hydrocarbon fraction. The cyclic pattern of the TPI within each ply is mirrored by the absolute concentration of triterpanes, steranes, and parameters such as Carbon Preference Index (CPI), Pr/nC{sub 17} and Ph/nC{sub 18}. All these changes are evident in a coal member only 2.2m thick. The petrographic and geochemical evidence suggest that the environmental affinity of the Barrett Coal is that of a delta-plain depositional setting. 27 refs., 4 figs.

Casareo, F.; Batts, B.; Conaghan, P.; George, S.; Jardine, D. [Macquarie University, North Ryde, NSW (Australia). School of Chemistry

1995-08-01

59

A New Permian Bivalve (Megadesmidae, Plesiocyprinellinae) from the Serrinha Member, Rio do Rasto Formation, Paraná Basin, Brazil  

Directory of Open Access Journals (Sweden)

Full Text Available During a recent inspection in the Paleontological Collection of the Institute of Geosciences, University of São Paulo,we have identified some specimens of undescribed mollusk bivalves. These called our attention for the following reasons:a) all specimens are internal molds of conjugated and closed articulated valves, some of them presenting fragments ofsilicified shells; b) all internal molds have similar general shape and internal characters, representing specimens of thesame taxon; c) the internal molds and silicified valves are well preserved, including fragile structures, which are hardlypreserved, such as the internal mold of the external ligament and muscle scars; d) and equally important, according tothe labels of all specimens, they were collected from rocks of the Passa Dois Group (Permian), Serrinha Member of theRio do Rasto Formation. Although who collected the shells and the precise geographic location of the specimens are stillunknown, the detailed study of these fossils brings us to the conclusion that they are morphologically distinct from anyheretofore published genus of the endemic fauna of bivalves from Passa Dois Group. Based in its general shape, hingestructure and muscles scars, the new form can be classified under the Family Megadesmidae Vokes, 1967, the most diversegroup of Permian bivalves of the Paraná Basin. The specimens are referred as Beurlenella elongatella new gen. and sp. Theshell shape and taphonomy indicate that this bivalve was a shallow, rapid, active burrower, suspension feeder, probablypreserved in situ, in event deposits.

Luiz Eduardo Anelli; Marcello Guimarães Simões; Juliana Machado David

2010-01-01

60

Pipe formation and degassing from the Tunguska Basin in East Siberia and the consequences for the end-Permian environment  

Science.gov (United States)

The end of the Permian period is marked by a perturbation of the global carbon cycle and the largest known mass extinction on Earth. The crisis is commonly attributed to the formation of the Siberian Traps Large Igneous Province although the causal mechanisms remain disputed. We have recently suggested that heating of Tunguska Basin sediments by the ascending magma played a key role in triggering the crisis. Our conclusions are based on extensive field work in Siberia in 2004 and 2006. Here we present new data on contact metamorphism and gas release. Heating of organic-rich shale and petroleum bearing evaporites led to greenhouse gas and halocarbon generation in sufficient volumes to cause global warming and atmospheric ozone depletion. This is supported by experiments on heated rock samples from Siberia. The gases were released to the end-Permian atmosphere partly through spectacular phreatomagmatic pipe structures with kilometre-sized craters, formed during sill emplacement 252.0 ± 0.4 million years ago. We demonstrate that the composition of the heated sedimentary rocks below the flood basalts is the most important factor in controlling whether a Large Igneous Provinces causes an environmental crisis or not.

Svensen, Henrik; Planke, Sverre; Fristad, Kirsten; Polozov, Alexander; Schmidbauer, Norbert

2010-05-01

 
 
 
 
61

Irradiation of quartz grains - a new method of sedimentological analysis applied to Permian - Carboniferous arenites in the Maranhao Basin - Brazil  

International Nuclear Information System (INIS)

The quartz grains of sediments and sedimentary rocks change their colour in variable intensity to smoky-quartz by X-ray irradiation, Co60 or in reactors, dependent on their temperature of cristallization. The quantity of quartz grains which were stained and which were not stained after being irradiated are related to rock types from the source areas. This method was applied for selected sandstones of different stratigraphical levels of the Permian-Carboniferous in the Maranhao Basin of Brazil. Studeis on heavy minerals of these sandstones have been done before. The heavy mineral associations of the Permian Pedra de Fogo Formation corroborate the results of the analysis of quartz grains which indicate a predominance of the metamorphic rocks in the source area. However, the heavy mineral parageneses of the Carboniferous Piaui Formation are different. This may be because the frequency of those heavy minerals depend directly on the stage of the weathering of the sandstones. It should be mentioned that heavy minerals occur in paleozoic sediments only in a small quantity, sometimes below 1% of the rock constitution. The irradiation analysis, which is applied for the predominant mineral in sandstones, appears to be most reliable. It is used here as the basis for the interpretations presented. (Author)

1980-10-25

62

Progress on the palynostratigraphy of the Permian strata in Rio Grande do Sul State, Paraná Basin, Brazil  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Com base na distribuição de grãos de pólen, duas unidades palinobioestratigráficas são formalisadas para o Permiano da Bacia do Paraná no Rio Grande do Sul. As unidades correspondem, da base para o topo, às zonas de intervalo Vittatina costabilis e Lueckisporites virkkiae, sendo a primeira subdividida em duas subzonas: Protohaploxypinus goraiensis e Hamiapollenites karrooensis. A primeira zona é considerada eopermiana (Eo a Mesocisuraliano), tendo sido detectada (more) junto à seqüência glacial e pós-glacial referente ao Grupo Itararé e Formação Rio Bonito, abrangendo ainda porções inferiores da Formação Palermo. A Zona Lueckisporites virkkiae, considerada neo-eopermiana a mesopermiana (neocisuraliana a eoguadalupiana), ocorre nas formações Palermo e Irati, podendo ainda ser estendida a estratos mais superiores da bacia (formações Serra Alta e Teresina). Suas principais características e seções de referência são apresentadas, bem como outros critérios requeridos pelo Código Estratigráfico Internacional na proposição de unidades bioestratigráficas. Abstract in english A review of published papers and results of analysis of new material have allowed improvements on the palynostratigraphy of the Permian strata of the Paraná Basin in Rio Grande do Sul State. Based on first and last occurrences of certain species of pollen taxa, two palynozones are formalized, these are the Vittatina costabilis and Lueckisporites virkkiae Interval Zones, in ascending order. The Vittatina costabilis Interval Zone is subdivided into two units, in ascending (more) order the Protohaploxypinus goraiensis and the Hamiapollenites karrooensis Subzones, and is recognized from the glacial (Itararé Group) and post-glacial sequence (Rio Bonito Formation and the base of the Palermo Formation). The Lueckisporites virkkiae Interval Zone occurs from the uppermost Rio Bonito Formation, through the Palermo and Irati formations, and into the Serra Alta and Teresina formations. The main characteristics and reference sections are established, as well as additional criteria to recognize biostratigraphical units, in accordance with the International Stratigraphic Guide. Palynostratigraphical correlation suggests that the Vittatina costabilis Zone concerns the Early Permian (early Cisuralian), while the Lueckisporites virkkiae is regarded as late Early Permian to early Middle Permian (late Cisularian to early Guadalupian).

Souza, Paulo A.; Marques-Toigo, Marleni

2005-06-01

63

Combined tide and wave influence on sedimentation of Lower Gondwana coal measures of central India: Barakar Formation (Permian), Satpura basin  

Energy Technology Data Exchange (ETDEWEB)

The coal-bearing Barakar succession of the Satpura basin is typical of the Gondwanan coal basins of peninsular India, in that it has previously been interpreted as continental in origin. The succession comprises three main facies associations, which are documented within this paper. Medium- to fine-grained muddy sandstone deposits of 5-75 m thickness are reinterpreted as tidally influenced delta deposits. Mudstone deposits of 3-20 m thickness with subordinate sandstones, coals and carbonaceous shales are reinterpreted as delta top deposits, and medium to coarse sandstones of 3-38 m thickness are interpreted as braided delta-top channels. The evidence for tidal influence arises from documentation of bidirectional cross-strata, tidal bundles, tidal rhythmites and periodic variation in foreset thickness. The recognition of tidal deposits indicates marine depositional conditions and significantly changes existing palaeogeographical models. This in turn has important implications for our understanding of the depositional setting and distribution of the Permian coals that occur across much of the southern supercontinent. Furthermore, coal-bearing tidal-delta deposits have not previously been described from continental interior basins.

Ghosh, S.K.; Chakraborty, C.; Chakraborty, T. [Indian State Inst., Calcutta (India). Geological Studies Unit

2004-01-01

64

Diagenetic overprint of original depositional architecture in a shallow water carbonate reservoir, Permian Basin, Texas  

Energy Technology Data Exchange (ETDEWEB)

Permian shallow-water carbonate reservoirs are highly heterogeneous because of complex variations in depositional facies produced by high-frequency sea level rise and fall. Accordingly, establishment of a cycle stratigraphic framework is fundamental to defining reservoir heterogeneity. Because nearly all of these reservoirs have experienced multiple episodes of dolomitization and sulfate emplacement, however, permeability is a n of diagenetic overprint. The extent to which diagenesis can affect permeability development is dramatically displayed in the Grayburg Formation (middle Permian) at South Cowden field, Weit Texas. Three scales of cyclicity contribute to original depositional facies heterogeneity in the Grayburg; high-frequency cycles, averaging 3 meters in thickness, constitute the fundamental architectural element in the main reservoir interval. Despite original depositional heterogeneity due to this cyclicity, however, permeability development is substantially the result of two diagenetic events: (1) dolomite diagenesis in vertically burrowed wackestones and packstones and (2) late alteration and removal of anhydrite. Dolomite diagenesis in vertically burrowed wackestones and packstones has produced irregular vertical zones of higher permeability in mud-dominated bases of high-frequency cycles in leeward ramp-crest highstand successions. Because dolomite diagenesis is concentrated in burrowed highstand successions, the distribution of resultant permeability trends is partly constrained by patterns of longterm accommodation and high frequency cyclicity. Anhydrite diagenesis, which is characterized by conversion to gypsum or by complete removal of sulfate, is developed along basinward margins of the field and cross cuts original depositional framework.

Ruppel, S.C.; Lucia, F.J. (Univ. of Texas, Austin, TX (United States))

1996-01-01

65

Diagenetic overprint of original depositional architecture in a shallow water carbonate reservoir, Permian Basin, Texas  

Energy Technology Data Exchange (ETDEWEB)

Permian shallow-water carbonate reservoirs are highly heterogeneous because of complex variations in depositional facies produced by high-frequency sea level rise and fall. Accordingly, establishment of a cycle stratigraphic framework is fundamental to defining reservoir heterogeneity. Because nearly all of these reservoirs have experienced multiple episodes of dolomitization and sulfate emplacement, however, permeability is a n of diagenetic overprint. The extent to which diagenesis can affect permeability development is dramatically displayed in the Grayburg Formation (middle Permian) at South Cowden field, Weit Texas. Three scales of cyclicity contribute to original depositional facies heterogeneity in the Grayburg; high-frequency cycles, averaging 3 meters in thickness, constitute the fundamental architectural element in the main reservoir interval. Despite original depositional heterogeneity due to this cyclicity, however, permeability development is substantially the result of two diagenetic events: (1) dolomite diagenesis in vertically burrowed wackestones and packstones and (2) late alteration and removal of anhydrite. Dolomite diagenesis in vertically burrowed wackestones and packstones has produced irregular vertical zones of higher permeability in mud-dominated bases of high-frequency cycles in leeward ramp-crest highstand successions. Because dolomite diagenesis is concentrated in burrowed highstand successions, the distribution of resultant permeability trends is partly constrained by patterns of longterm accommodation and high frequency cyclicity. Anhydrite diagenesis, which is characterized by conversion to gypsum or by complete removal of sulfate, is developed along basinward margins of the field and cross cuts original depositional framework.

Ruppel, S.C.; Lucia, F.J. [Univ. of Texas, Austin, TX (United States)

1996-12-31

66

Outcrop analogs for mdoeling heterogeneous restricted platform reservoirs: Grayburg Formation (Guadalupian) of the Guadalupe Mountains and subsurface Permian basin  

Energy Technology Data Exchange (ETDEWEB)

Restricted platform deposits of the Permian basin have produced more than 10 billion bbl of oil, but because of complex internal facies architecture ultimate recovery rarely exceeds 30% of original oil in place. The first step in locating and exploiting the substantial unrecovered hydrocarbons in this play is developing improved development-oriented (as opposed to exploration-oriented) models of facies/permeability heterogeneity. Quantitative geologic/engineering analysis of outcrops analogous to reservoirs allows characterization of styles of variability and three-dimensional geometry at interwell, reservoir, and play scales beyond that possible using limited subsurface data. The Guadalupian Grayburg Formation is exposed in the northern Guadalupe Mountains less than 60 mi west of reservoir trends on the Northwest Shelf and Central Basin platform. These outcrops provide a test for the development of outcrop-based reservoir heterogeneity models. A 10-mi dip section of the mixed siliciclastic/carbonate Grayburg of the Guadalupes exhibits inner ramp (4-mi dip width), ramp-crest ooid shoal/tidal flat (4 mi dip width), and outer ramp fusulinid-peloid (2-mi dip width) facies tracts. Maximum facies heterogeneity occurs in upward-shallowing cycles of the ramp crest where porous ooid shoals pass laterally into tight peloid packstones in less than 1,000 ft. Siliciclastic sands are intercalated in all facies tracts typically as sheets. However, in the ramp crest they also occur as 15-ft-thick by 50-ft-wide channels dissecting ooid shoals. Grayburg reservoirs on the eastern side of the Central Basin platform contain facies tracts and styles of heterogeneity analogous to the outcrop. Production trends from these reservoirs similarly illustrate most variability in grainstone shoal complexes.

Kerans, C.; Nance, H.S.; Bebout, D.G. (Univ. of Texas, Austin (USA))

1990-05-01

67

Preliminary study of uranium in Pennsylvanian and lower Permian strata in the Powder River Basin, Wyoming and Montana, and the Northern Great Plains  

International Nuclear Information System (INIS)

Persistent and widespread radiometric anomalies occur in Pennsylvanian and Lower Permian strata in the subsurface of the northern Great Plains and the Powder River Basin. The primary host lithology of these anomalies is shale interbedded with sandstone, dolomite, and dolomitic sandstone. Samples from the project area indicate that uranium is responsible for some anomalies. In some samples there seems to be a correlation between high uranium content and high organic-carbon content, which possibly indicates that carbonaceous material acted as a trapping mechanism in some strata. The Pennsylvanian and Permian rocks studied are predominantly marine carbonates and clastics, but there are rocks of fluvial origin in the basal Pennsylvanian of Montana, North Dakota, and South Dakota and in the Pennsylvanian and Permian deposits on the east flank of the Laramie Mountains. Fine-grained clastic rocks that flank the Chadron arch in western Nebraska are possibly of continental origin. The trend of the Chadron arch approximately parallels the trend of radiometric anomalies in the subsurface Permian-Pennsylvanian section. Possible source areas for uranium in the sediments studied were pre-Pennsylvanian strata of the Canadian Shield and Precambrian igneous rocks of the Ancestral Rocky Mountains

1977-01-01

68

Variability of the Rotliegend sandstones in the Polish part of the Southern Permian Basin - permeability and porosity relationships  

Directory of Open Access Journals (Sweden)

Full Text Available The Flow Zone Index, FZI, applied to order relations between the effective porosity and permeability of the Rotliegend sandstones in the Polish part of the Southern Permian Basin turns out to be a useful and effective factor to evaluate ability of media flow in a rock formation. A dataset of over 2000 samples from 78 wells was analysed. Based only on porosity and permeability, FZI includes all non-parameterized features of rocks as tortuosity and diameters of porous channels, volume of trapped parts of capillary roads, specific surface of pore space, and others. When FZI increases, the ability of fluid to move through the porous space increases. In most cases, the Rotliegend sandstones reveal FZI in the range of 0.5-2.0. The highest FZI, ca. 100, is related to fractured part of the studied formation. The combination of FZI and facies information from several wells in the study area (over 1200 samples) showed a good correlation. On the basis of FZI we can divide a set of samples of the Rotliegend sandstone into groups of defined fluid flow abilities and relate them to facies. Also, we show the way of estimation of the reliable values of permeability in full geological log of a borehole on the basis of FZI, and the total porosity determined from well logging interpretation.

Jadwiga JARZYNA; Edyta PUSKARCZYK; Maria BA?A; Bartosz PAPIERNIK

2009-01-01

69

High-resolution stratigraphic forward modeling: A case study of the lower-middle San Andres formation, Permian basin  

Energy Technology Data Exchange (ETDEWEB)

This study has attempted to calibrate Shell's two-dimensional (2-D) basin modeling program as an exploration tool by simulating the stratigraphy of a mixed carbonate/clastic third-order depositional sequence. The lower-middle San Andres Formation was selected because available log, core, and outcrop data from the Northwest Shelf area, Permian basin, provided an excellent calibration set. A regional stratigraphic cross section from the Cato-Chaveroo to the Wasson fields was constructed delineating lithology and porosity distribution. Approximately 10 shoaling-upward depositional cycles were interpreted. A higher frequency, five-in-one cyclicity was also interpreted based on core and outcrop data. The observed stratigraphy was simulated using a composite eustasy consisting of third-order (2,000,000 yr), fourth-order (100,000 yr), and fifth-order (20,000 yr) sinusoids each at five-meter amplitudes. Subsidence input was constrained by back-stripped tectonic subsidence curves calculated from well data. Sedimentation parameters were interactively derived. New empirically based algorithms were used to model Dunham lithofacies, environmental facies, and sabkha anhydrite distribution. Synthetic log and 2-D synthetic seismic profiles were constructed from the simulation output. The simulation results suggest that (1) relative sea level is the dominant control on the observed depositional cyclicity, (2) the distribution of regional seal facies (anhydrite) reflects falling sea level and prolonged exposure, (3) limestone-dolomite trends on the shelf are grossly related to environment and (4) the distribution of grainstones and packstones (potential reservoirs) occurs as fourth- and fifth-order offlapping and aggradational pods. The synthetic log signatures compared to [open quotes]real[close quotes] logs substantiate the interpreted depositional cyclicity, but also point out the difficulty in interpreting high-order cycles based on log data alone.

Shuster, M.W. (KSEPL (Shell Research), Rijswijk (Netherlands)); Childers, D.W. (Shell Western Exploration and Production Inc., Houston, TX (United States))

1993-09-01

70

PLAY ANALYSIS AND DIGITAL PORTFOLIO OF MAJOR OIL RESERVOIRS IN THE PERMIAN BASIN: APPLICATION AND TRANSFER OF ADVANCED GEOLOGICAL AND ENGINEERING TECHNOLOGIES FOR INCREMENTAL PRODUCTION OPPORTUNITIES  

Energy Technology Data Exchange (ETDEWEB)

The Permian Basin of west Texas and southeast New Mexico has produced >30 Bbbl (4.77 x 10{sup 9} m{sup 3}) of oil through 2000, most of it from 1,339 reservoirs having individual cumulative production >1 MMbbl (1.59 x 10{sup 5} m{sup 3}). These significant-sized reservoirs are the focus of this report. Thirty-two Permian Basin oil plays were defined, and each of the 1,339 significant-sized reservoirs was assigned to a play. The reservoirs were mapped and compiled in a Geographic Information System (GIS) by play. Associated reservoir information within linked data tables includes Railroad Commission of Texas reservoir number and district (Texas only), official field and reservoir name, year reservoir was discovered, depth to top of the reservoir, production in 2000, and cumulative production through 2000. Some tables also list subplays. Play boundaries were drawn for each play; the boundaries include areas where fields in that play occur but are <1 MMbbl (1.59 x 10{sup 5} m{sup 3}) of cumulative production. This report contains a summary description of each play, including key reservoir characteristics and successful reservoir-management practices that have been used in the play. The CD accompanying the report contains a pdf version of the report, the GIS project, pdf maps of all plays, and digital data files. Oil production from the reservoirs in the Permian Basin having cumulative production >1 MMbbl (1.59 x 10{sup 5} m{sup 3}) was 301.4 MMbbl (4.79 x 10{sup 7} m{sup 3}) in 2000. Cumulative Permian Basin production through 2000 from these significant-sized reservoirs was 28.9 Bbbl (4.59 x 10{sup 9} m{sup 3}). The top four plays in cumulative production are the Northwest Shelf San Andres Platform Carbonate play (3.97 Bbbl [6.31 x 10{sup 8} m{sup 3}]), the Leonard Restricted Platform Carbonate play (3.30 Bbbl 5.25 x 10{sup 8} m{sup 3}), the Pennsylvanian and Lower Permian Horseshoe Atoll Carbonate play (2.70 Bbbl [4.29 x 10{sup 8} m{sup 3}]), and the San Andres Platform Carbonate play (2.15 Bbbl [3.42 x 10{sup 8} m{sup 3}]).

Shirley P. Dutton; Eugene M. Kim; Ronald F. Broadhead; Caroline L. Breton; William D. Raatz; Stephen C. Ruppel; Charles Kerans

2004-05-01

71

Ichnology of the non-marine deposits of the Boskovice Basin (Carboniferous-Permian, Czech Republic)  

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Full Text Available In the area of the Boskovice Basin, simple ichnoassemblages and ichnofabric patterns characterize a suite of lacustrine and fluvial deposits. The succession of ichnofabrics enables us to correlate several sections in the northern part of the basin, supporting the correlation of the previously recognized Ba?ov, Míchov and Obora horizons. The mostly finegrained lacustrine deposits below bituminous limestones contain Planolites beverleyensis, Planolites montanus, amphibian footprints, and rare Cruziana problematica. Reddish sandstones, which can be interpreted as alluvial plain deposits, contain Planolites, Scoyenia, 'star-like traces', and Diplocraterion. In the southern part of the basin, the coal-bearing strata are characterized by generally poor bioturbation, with isolated levels of 'root spots' and Planolites. The lowermost strata of the overlying red-bed unit show intensive and rhythmical Planolites ichnofabric, the intensity and uniformity of which decrease upwards.

Mikuláš R; Martínek K

2006-01-01

72

Palynology of the Permian San Miguel Formation (Western Paraná Basin, Paraguay): Gondwanan biostratigraphic correlations  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The palynological analysis of five samples from three levels in cores of the Mallorquín-1 well (Paraná Basin, eastern Paraguay) is presented here. The borehole penetrated the San Miguel Formation, the basal lithostratigraphic unit of the Independencia Group. This palynoflora represents the westernmo...

Pérez Loinaze, V.S.

73

Radiometric dating of ochoan (permian) evaporites, WIPP site, Delaware basin, New Mexico, USA  

International Nuclear Information System (INIS)

[en] The authors have attempted radiometric dating of halide-sulfate salts and clay minerals from the Delaware Basin, New Mexico, USA, as part of geochemical study of the stability of the evaporite sequence at the WIPP (Waste Isolation Pilot Plant - a US DOE facility) site. They undertook this dating to determine: (1) primary age of evaporite genesis or time(s) of recrystallization, (2) if previously undated evaporite minerals (leonite, polyhalite, kieserite) give useful data, and (3) if the detrital clay minerals have been radiometrically reset at any time following their incorporation into the evaporite medium. They have shown earlier that polyhalites can indeed be successfully dated by the K-Ar method, and once corrections are applied for admixed halide minerals, dates of 210-230 Ma for the Delaware Basin are obtained. Rb-Sr isochrons from early stage sylvites-polyhalites-anhydrites yield 220 +/- 10 Ma, even when some sylvites yield lower K-Ar dates due to loss of 40Ar*. K-Ar dates on leonites and kieserites are also low due to 40Ar* loss, but their Rb-Sr dates are higher. Detrital clay minerals from the Delaware Basin collectively yield a highly scattered isochron (390 +/- 77 Ma), but samples from a local area, such as the WIPP Site, give a much better age of 428 +/- 7 Ma. These dates show that the interaction between the clay minerals and the evaporitic brines was insufficient to reset the clay minerals Rb-Sr systematics. In a related study, they note that a dike emplaced into the evaporite at 34 Ma had only very limited effect on the intruded rocks; contact phenomena were all within 2 m of the dike. All of their geochemical (radio-metric and trace element) studies of the WIPP site argue for preservation of the isotopic and chemical integrity of the major minerals for the past 200 Ma. 19 references, 1 figure, 5 tables

1987-01-01

74

Coricladus quiteriensis gen. et sp. nov., a new conifer in Southern-Brazil Gondwana (Lower Permian, Paraná Basin)  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Um novo taxon de coníferas (Coricladus quiteriensis) é descrito a partir de fragmentos de megafósseis vegetais do nível de roof-shale do Afloramento Quitéria (Formação Rio Bonito - Permiano Inferior - Sul da Bacia do Paraná - Rio Grande do Sul - Brasil). Esta comunidade megaflorística é incluída na Zona Botrychiopsis - Sub-Zona Botrychiopsis valida (Kunguriano/Roadiano). A assembléia, preservada sob forma de impressões, não apresenta registros de caracteres (more) epidérmicos, e é composta por ramos vegetativos isolados, portando folhas aciculares dispostas helicoidalmente, as quais possuem uma nervura central conspícua. Além disso, são registrados ramos férteis com folhas esparsas e irregulares e cones terminais. Ramos principais, áfilos, conectados organicamente a ramos vegetativos e férteis, são raros. Escamas reprodutivas femininas, dispostas em um só plano, estão organizadas em cones terminais, compostos por 4 (quatro) escamas ovulíferas e 8 (oito) sementes anátropas alongado-elípticas. Dados paleoecológicos indicaram um habitat mesófilo a higrófilo, desenvolvido em um ambiente pantanoso. Abstract in english A new taxon of conifers (Coricladus quiteriensis) is described based on megafloristic remains from the roofshale level at the Quitéria Outcrop (Rio Bonito Formation - Lower Permian - Southern Paraná Basin - Rio Grande do Sul - Brazil). This megafloristic community is included in the Botrychiopsis Zone - Botrychiopsis valida Sub-Zone (Kungurian/Roadian). The assemblage, preserved as impressions, do not present remains of epidermic characters, and is composed mainly of is (more) olated vegetative branches with spirally disposed acicular leaves, presenting a conspicuous central vein and also isolated fertile branches with sparse and irregular leaves and terminal cones. Leafless principal branches, organically connected with sterile and fertile branches, are rare. Reproductive feminine scales, disposed in a plane, are organized in lax terminal cones on branches, composed by 4 (four) distal ovuliferous scales, and 8 (eight) elliptical-elongated anatropous seeds. Paleoecological data pointed out to a mesophylous to higrophylous habitat in swampy environments.

Jasper, André; Ricardi-Branco, Fresia; Guerra-Sommer, Margot

2005-03-01

75

Petrographic characteristics and palaeoenvironment of the Permian coal resources of the Barapukuria and Dighipara Basins, Bangladesh  

Science.gov (United States)

Twenty-seven coal samples from the Barapukuria and Dighipara Coal Basins of Bangladesh were analysed for their maceral content, petrographic characteristics and vitrinite reflectance. The most predominant maceral was the inertinite group (mean 40%), followed by vitrinite (mean 31%) and liptinite (mean 22%), with considerable amounts of mineral matter (mean 7%). Semifusinite, fusinite and inertodetrinite were the most common macerals of the inertinite group. Collotelinite, collodetrinite and vitrodetrinite were the most frequently found macerals of the vitrinite group, while sporinite and cutinite were the most common in the liptinite group. Clay minerals occurred in higher concentrations than other minerals. The measured vitrinite reflectance values (%Ro) ranged from 0.71 to 0.80, indicating a high volatile bituminous B ranking.Facies modelling using maceral composition and maceral indices suggested an environment of forest swamps with alternating oxic-anoxic depositional conditions. Microlithotype-dependent depositional modelling indicated evolution in limno-telmatic zones under fluvio-lacustrine control, accompanied by the development of upper to lower deltaic plain conditions. A terrestrial origin with dry forest to piedmont plain conditions was suggested by the Gelification Index (GI) and Tissue Preservation Index (TPI). The lateral variation of the measured TPI values indicated an increase in the rate of basin subsidence. A cross-plot of the Ground Water Index (GWI) vs. the Vegetation Index (VI) suggested mires under ombotrophic to mesotrophic hydrogeological conditions containing herbaceous plants.

Farhaduzzaman, Md.; Abdullah, Wan Hasiah; Islam, Md. Aminul

2013-03-01

76

Permian bivalves of the Taciba Formation, Itararé Group, Paraná Basin, and their biostratigraphic significance  

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Full Text Available A small and poorly diversified bivalve fauna from Taciba Formation, Itararé Group, Paraná Basin (State of Santa Catarina,Mafra Municipality), is described in this paper for the first time, based on new findings. The fauna is recorded in a 30 cmthick interval of fine sandstone locally at the top of Taciba Formation, in the Butiá quarry. The studied fossil-bearing sandstonebed is a marine intercalation recording a brief eustatic rise in sea-level, probably following glacier retreat and climateamelioration at the end of a broad glacial scenario. The fauna is mainly dominated by productid brachiopods, which are notdescribed here, and rare mollusk shells (bivalves and gastropods). Two bivalve species were identified: Myonia argentinensis(Harrington, 1955), and Aviculopecten multiscalptus (Thomas, 1928). The presence of Myonia argentinensis is noteworthysince this species is also present in the Baitaca assemblage found in marine siltstones (Baitaca assemblage) of theRio do Sul Formation, cropping out at the Teixeira Soares region, Paraná State. This species is also recorded in the bivalvefauna from the Bonete Formation, Pillahinco Group, Sauce Grande Basin, Buenos Aires Province, in Argentina. Hence, themarine bivalves of the Taciba Formation are associated with the transgressive event that characterizes the Eurydesma fauna,indicating a Late Asselian-Sakmarian age for the bivalve fauna. Presence of the Myonia argentinensis megadesmid speciesreinforces the Gondwanic nature of the studied fauna.

Marcello Guimarães Simões; Jacqueline Peixoto Neves; Luiz Eduardo Anelli; Luiz Carlos Weinschütz

2012-01-01

77

Sequence stratigraphy and depositional facies of the Silurian-Devonian interval of the northern Permian basin  

Energy Technology Data Exchange (ETDEWEB)

The Silurian and Devonian intervals of the northern Central Basin platform area of west Texas and southeastern New Mexico include the Fusselman, Wristen, and Thirtyone formations and the Woodford Shale. The carbonate-rich Fusselman, Wristen, and Thirtyone formations record a transition from ramp to platform deposition. Oolite grainstones of the lower Fusselman Formation were deposited in a ramp setting during an Upper Ordovician/Lower Silurian transgression. The overlying crinoid packstones and grainstones represent shoals that developed along a break in slope separating the evolving platform from a southward-dipping starved basin. By the close of Fusselman deposition, the platform was well developed, with shallow peridtidal mudstones and wackestones, and high-energy grainstones deposited as near-parallel facies tracts over the platform area. The platform system became fully developed during the deposition of the Wristen Formation. Porous dolomitic peridtidal and platform margin facies grade downdip into nonporous, limy and argillaceous open-shelf facies. Platform facies are typified by numerous shallowing-upward parasequences that terminated at subaerial exposure surfaces. The rocks of the Lower Devonian Thirtyone Formation were deposited as a wedge that onlaps the exposed Silurian platform margin. This formation contains a porous, chert-rich, lowstand deposit; a transgressive disconformity; and variably porous, grain-rich highstand deposits representing an overall sea level rise. A major unconformity marks the contact between the karsted upper surface of the Thirtyone Formation and the overlying organic-rich, anoxic Woodford Shale.

Canter, K.L.; Geesaman, R.C. (Coyote Geologic Services, Boulder, CO (United States)); Wheeler, D. (Ensign Oil and Gas, Denver, CO (United States))

1992-04-01

78

Cyclicity in the Middle Permian San Andres Formation, Palo Duro Basin, Texas Panhandle  

Energy Technology Data Exchange (ETDEWEB)

The San Andres Formation is largely composed of cyclic sequences of carbonate, anhydrite, and halite. Using geophysical log data, the authors traced these cycles across the entire Palo Duro Basin; four oversized plates reproduce cross sections that document the correlations. Cores received from 10 Department of Energy stratigraphic test wells were studied, and at least one cored well was incorporated in each cross section for precise lithologic control. Core photographs, showing typical textures of evaporite rocks and associated facies, are reproduced in the text. The authors discuss depositional systems, propose extrabasinal correlations of the San Andres Formation cycles, document lateral facies relationships and variations in the style of cyclicity, and note structural influences on sedimentation in the formation. The authors conclude that the entire suite of evaporitic cyclic facies reflects predominantly shallow-water marine deposition in contrast to previously proposed sabkha-like models of deposition. Systematic changes in thickness and completeness of the cycles allow the authors to divide the San Andres into three informal genetic sequences. These sequences share a similar cyclic mode but are characterized by differences in tempo of cyclicity, reflecting changes in regional basin subsidence rate of frequency of sea-level change or both.

Fracasso, M.A.; Hovorka, S.D.

1986-01-01

79

Petrography and depositional environments of the Permian coal deposits of Deoghar basin, Bihar  

Energy Technology Data Exchange (ETDEWEB)

An attempt has been made to carry out the petrographic characterization of coals from the Deoghar basin and to reconstruct the palaeo environmental conditions of coal formation using macerals and microlithotypes as tools. For this purpose, a large number of pillar coal samples from the Karharbari and Barakar seams were collected and were subjected to detailed petrographic examination. The results indicate that the Karharbari coals are rich in inertinite while the Barakar coals are comparatively rich in vitrinite. The rank of Deoghar coals (as per ASTM system), on the basis of the mean of random vitrinite reflectance, has been found to range between Sub-Bituminous 'B' and High Volatile 'C' Bituminous. The quantitative relationships of macerals, microlithotypes and mineral matter show that these coals have originated from the transitional plant communities in open to forest moor and under limno-telmatic to limnic conditions. Moreover, the Karharbari coals have evolved under oxic moor conditions with sudden high flooding while the Barakar coals have evolved under comparatively wet moor conditions with intermittent moderate to high flooding. Low values of TPI and GI indicate periodic dryness in the basin. This contention is supported by the dominance of inertodetrinite, particularly in the coals of Karharbari Formation.

Singh, M.P.; Singh, P.K.; Singh, A.K. [Banaras Hindu University, Varanasi (India). Dept. of Geology

2003-04-01

80

Geoscience/Engineering Characterization of the Interwell Environment in Carbonate Reservoirs Based on Outcrop Analogs, Permian Basin, West Texas and New Mexico.  

Energy Technology Data Exchange (ETDEWEB)

The objective of this project is to investigate styles of reservoir heterogeneity found in low permeability pelleted wackestone/packstone facies and mixed carbonate/clastic facies found in Permian Basin reservoirs by studying similar facies exposed in the Guadalupe Mountains. Specific objectives for the outcrop study include construction of a stratigraphic framework, petrophysical quantification of the framework, and testing the outcrop reservoir model for effects of reservoir heterogeneity on production performance. Specific objectives for the subsurface study parallel objectives for the outcrop study.

Lucia, F.J.; Kerans, C.

1996-12-31

 
 
 
 
81

Record of the genus Lycopodites in the Lower Permian of Paraná Basin, Brazil  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese O gênero Lycopodites, que engloba formas herbáceas de licópsidas, apresenta ampla distribuição temporal e espacial durante o Paleozóico no Hemisfério Norte, iniciando seu registro no Devoniano da Europa. Já no Paleozóico do Gondwana, até o presente momento, somente Lycopodites amazonica Dolianiti havia sido reportada para o Devoniano Médio da Amazônia (Grupo Curuá). Assim, os exemplares reportados no presente trabalho como Lycopodites sp., provenientes de roc (more) has sedimentares do Subgrupo Itararé, SP, e Lycopodites riograndensis sp. nov., coletados na Formação Rio Bonito, RS, representam as formas férteis mais antigas registradas para o Gondwana e as primeiras a serem descritas para a Bacia do Paraná. A sua presença em camadas depositadas após o término da glaciação neopaleozóica, evidencia o ingresso de novos taxa em latitudes altas, bem como a diversidade das licópsidas presentes na Bacia, já esboçada através dos abundantes esporos associados à Classe Lycopsida presentes nas assembléias de palinomorfos. Abstract in english The genus Lycopodites, which encompasses the herbaceous forms of the lycopsids, presents broad time and spacial distribution during the Paleozoic in the Northern Hemisphere, with its initial records dating from the European Devonian. As to Gondwanan Paleozoic, to this moment, only Lycopodites amazonica Dolianiti had been reported for the Amazonian Middle Devonian (Curuá Group). Thus, the specimens reported in this study such as Lycopodites sp., coming from sedimentary ro (more) cks of the Itararé Subgroup, São Paulo State, and Lycopodites riograndensis sp. nov., collected in Rio Bonito Formation, Rio Grande do Sul, represent the oldest fertile forms recorded for Gondwana and the first ones to be described for the Paraná Basin. Its presence in layers, deposited after the end of the Neopaleozoic Glaciation, shows the appearance of new taxa in high latitudes, as well as the diversity of the lycopsids present in the Basin, previously indicated through the abundance of spores associated to the Class Lycopsida present in the palinomorphous assemblages.

Salvi, Juliana; Jasper, André; Ricardi-Branco, Fresia; Bernardes-de-Oliveira, Mary Elizabeth C.; Guerra-Sommer, Margot

2008-09-01

82

Record of the genus Lycopodites in the Lower Permian of Paraná Basin, Brazil  

Directory of Open Access Journals (Sweden)

Full Text Available The genus Lycopodites, which encompasses the herbaceous forms of the lycopsids, presents broad time and spacial distribution during the Paleozoic in the Northern Hemisphere, with its initial records dating from the European Devonian. As to Gondwanan Paleozoic, to this moment, only Lycopodites amazonica Dolianiti had been reported for the Amazonian Middle Devonian (Curuá Group). Thus, the specimens reported in this study such as Lycopodites sp., coming from sedimentary rocks of the Itararé Subgroup, São Paulo State, and Lycopodites riograndensis sp. nov., collected in Rio Bonito Formation, Rio Grande do Sul, represent the oldest fertile forms recorded for Gondwana and the first ones to be described for the Paraná Basin. Its presence in layers, deposited after the end of the Neopaleozoic Glaciation, shows the appearance of new taxa in high latitudes, as well as the diversity of the lycopsids present in the Basin, previously indicated through the abundance of spores associated to the Class Lycopsida present in the palinomorphous assemblages.O gênero Lycopodites, que engloba formas herbáceas de licópsidas, apresenta ampla distribuição temporal e espacial durante o Paleozóico no Hemisfério Norte, iniciando seu registro no Devoniano da Europa. Já no Paleozóico do Gondwana, até o presente momento, somente Lycopodites amazonica Dolianiti havia sido reportada para o Devoniano Médio da Amazônia (Grupo Curuá). Assim, os exemplares reportados no presente trabalho como Lycopodites sp., provenientes de rochas sedimentares do Subgrupo Itararé, SP, e Lycopodites riograndensis sp. nov., coletados na Formação Rio Bonito, RS, representam as formas férteis mais antigas registradas para o Gondwana e as primeiras a serem descritas para a Bacia do Paraná. A sua presença em camadas depositadas após o término da glaciação neopaleozóica, evidencia o ingresso de novos taxa em latitudes altas, bem como a diversidade das licópsidas presentes na Bacia, já esboçada através dos abundantes esporos associados à Classe Lycopsida presentes nas assembléias de palinomorfos.

Juliana Salvi; André Jasper; Fresia Ricardi-Branco; Mary Elizabeth C. Bernardes-de-Oliveira; Margot Guerra-Sommer

2008-01-01

83

Diagenesis of Permian (Guadalupian) San Andres Formation, Central Basin platform, west Texas  

Energy Technology Data Exchange (ETDEWEB)

Reflux of Guadalupian brines is interpreted to have been the dominant mechanism of dolomitization of San Andres subtidal carbonates on and near the Central Basin platform. Other important diagenetic processes include anhydrite emplacement and a late stage of diagenesis linked to sulfate reduction. Supratidal dolomite has an average delta/sup 18/O of +4.5 +/- 0.5 per thousand (PDB, n = 9), suggesting stabilization in sea water evaporated to gypsum saturation. The strontium isotopic signature (/sup 87/Sr//sup 86/Sr) for these dolomites is 0.7068 +/- 0.0001 (n = 2) in the upper San Andres and 0.7071 +/- 0.0001 (n = 2) in the lower San Andres, reflecting differences in the timing of dolomitization of these strata. Because these dolomites have strontium isotopic ratios that correspond with the depositional ages predicted from a strontium sea water curve from the Palo Duro basin, supratidal dolomitization is interpreted to have occurred penecontemporaneous with sedimentation. The delta/sup 18/O of intertidal dolomite averages +3.6 +/- 0.5 per thousand (PDB, n = 12); this may indicate dolomitization by a less-evaporated sea water, although a later stabilization event is also possible. Gray, nonporous fusulinid wackestones typically have delta/sup 18/O values that average +4.7 +/- 0.5 per thousand (PDB, n = 15), again suggesting formation in the presence of gypsum-saturated brines. Patchy, brown, porous subtidal dolomites have delta/sup 18/O values that are about 1.6 +/- 0.9 per thousand (PDB, n = 1) less than adjacent unaltered samples. The lighter oxygen isotopes and intimate association of the two types of dolomite suggest that patchy dolomite recrystallized at a later time, either at a higher temperature or in an isotopically lighter fluid.

Leary, D.A.; Vogt, J.N.

1987-05-01

84

Petrographic characterization and evolution of the Permian coal deposits of the Rajmahal Basin, Bihar, India  

Energy Technology Data Exchange (ETDEWEB)

Lower Gondwana rocks are exposed as narrow bands and discontinuous patches along the western edges of the Rajmahal Hills covering a large area of the Bengal Basin, North Bengal and Purnea. Two coalfields - Hura and Chuperbhita - have productive coal mines. Pillar coal samples from the working coal seams of Hura and Chuperbhita coalfields were collected and subjected to a detailed petrographic and geochemical study using refined procedures on a large number of samples. The results of the micropetrographic study reveal that the Rajmahal coals are rich in liptinite and inertinite contents. The fluorescence microscopy indicates that a major part, identified as argillaceous mineral matter under white incident light, is composed of liptinite macerals such as bituminite, fluorinite and exsudatinite. The volatile matter and reflectance suggest these coals are subbituminous to high volatile bituminous B/C in rank. The quantitative relationships among maceral and microlithotype suggest that these coals were deposited in limnic to limno-telmatic conditions under very wet conditions that resulted from undisturbed peat that developed in situ along with subaquatic (limnic) sedimentation in swampy lakes. Further, the GI and TPI values indicate that the Hura coals were formed under oxic moor conditions with sudden episodes of flooding, while the Chuperbhita coals have originated in wet moors with intermittent moderate to high flooding. In addition, GI values suggest the formation of these coals in an upper delta/alluvial valley with braided plains. 33 refs., 8 figs., 5 tabs.

Singh, M.P.; Singh, P.K. [Banaras Hindu University, Varanasi (India)

1996-01-01

85

The Carboniferous-Permian boundary in the central western Argentinean basins: paleontological evidences/ El límite Carbonífero-Pérmico en las cuencas del centro oeste de Argentina: evidencias paleontológicas  

Scientific Electronic Library Online (English)

Full Text Available Abstract in spanish Las cuencas del centro oeste de Argentina, Río Blanco, Calingasta-Uspallata y el sector oeste de la cuenca Paganzo, contienen las secuencias marinas más completas para el estudio del límite Carbonífero-Pérmico en Gondwana. Un estudio detallado de secciones estratigráficas claves ha permitido la identificación de las asociaciones megaflo-rísticas NBG y de Intervalo, y de la palinozona DM (Raistrickia densa-Convolutispora muriornata), del Carbonífero Tardío, en la (more) parte inferior de dichas secciones; en tanto, en la parte media superior de las secciones estudiadas, se han identificado la biozona de invertebrados T-S (Tivertonia jachalensis-Streptorhynchus inaequiornatus) y la palinozona FS (Pakhapites fusus-Vittatina subsaccata), ambas asignadas al Pérmico Temprano. El registro de estas asociaciones diagnósticas de mega/microflora e invertebrados marinos provee un esquema bioestratigráfico integrado que permite ubicar el límite Carbonífero-Pérmico en las cuencas del centro oeste de Argentina. Abstract in english The central western Argentinean basins of Río Blanco, Calingasta-Uspallata and western Paganzo, enclose the most complete marine successions used for examining the Carboniferous-Permian boundary in Gondwana. A detailed review of the key stratigraphical sections has allowed the identification of the latest Carboniferous assemblages; NBG, Interval megafloristic Zone and DM (Raistrickia densa-Convolutispora muriornata) Palynological Zone in the lower part, and the earliest (more) Permian T-S (Tivertonia jachalensis-Streptorhynchus inaequiornatus) invertebrate Zone and FS (Pakhapitesfusus-Vittatina subsaccata) Palynological Zone in the upper part. This diagnostic mega/microflora and marine invertebrate paleontological evidence provides a biostratigraphical framework for the definition of the Carboniferous-Permian boundary inside the basins of central western Argentina.

Cisterna, Gabriela A; Sterren, Andrea F; Gutiérrez, Pedro R

2011-07-01

86

Diagenesis and secondary porosity enhancement from dissolution of analcime cement in reservoir sandstones: The Upper Permian Pingdiquan Formation, Junggar basin, northwest China  

Energy Technology Data Exchange (ETDEWEB)

The Junggar Basin is one of the largest and most important oil-producing basins in China, in which Upper Permian lacustrine oil shales are among the thickest and richest petroleum source rocks in the world. The Upper Permian Pingdiquan Formation was deposited predominantly in fan-delta sequences within a lacustrine setting. The Pingdiquan Formation sandstones constitute the principal oil reservoirs, whereas the interbedded black shales are the predominant oil source rocks. The early diagenetic mineral assemblage in the sandstones comprises siderite, pyrite, analcime, albite, calcite and authigenic quartz as well as trace amount of halite; By contrast, the late diagenetic minerals are characterized by authigenic K-feldspar, ankerite, and minor amounts of mixed-layer clay minerals. Petrographic, mineralogical and available paleoecological data suggest that early authigenic minerals in the sandstones were controlled by alternating periodic fresh water and saline/alkaline water episodes in a lacustrine environment. The cementation of siderite, analcime, calcite and albite occluded the substantial porosity in the sandstones at an early diagenetic stage. However, extensive dissolution of analcime cement and labile detrital feldspars occurred during burial diagenesis, resulting in a significant secondary porosity enhancement in the sandstones and making them very good quality oil reservoirs. The origin of secondary porosity is related to the generation of various organic acids due to organic maturation of the interbedded exceptionally organic-rich oil shales.

Zhaohui, T.; Longstaffe, F.J. [Univ. of Western Ontario, London (Canada); Parnell, J. [Univ. of Belfast (United Kingdom)

1996-12-31

87

Dispersal Syndromes of fossil Seeds from the Lower Permian of Paraná Basin, Rio Grande do Sul, Brazil  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese A Análise morfológica das sementes tem sido um importante objeto em estudos ecológicos modernos, uma vez que fornece evidências sobre a biologia e as adaptações das plantas-mãe de sementes. Entretanto, este tipo de estudo tem sido restrito a ecologia de plantas modernas e é raramente utilizado em interpretações de dados paleozóicos. A partir do entendimento da análise das sindromes de dispersão como uma importante ferramenta para reconstruções paleoecológi (more) cas, este estudo oferece uma primeira abordagem utilizando essa ferramenta com sementes do Permiano Inferior do Sul da Bacia do Paraná, no Rio Grande do Sul. Baseado em sementes previamente classificadas e utilizando seus dados biológicos e tafonômicos, a síndrome de dispersão foi interpretada, e a classificação das sementes nos grupos successionais (pioneira, secundária inicial ou secundária tardia) foi sugerida. Sete morfoespécies foram analisadas: Samaropsis gigas, representando uma espécie de secundária-tardia, vivendo próximo a corpos d'água, com síndrome de dispesão hidrocórica; Samaropsis kurtzii, típica espécie de sucessão secundária inicial, apresentando a anemocoria como síndrome de dispersão e habitando áreas distantes em relação a corpos d'água; Samaropsis aff. S. millaniana, Cordaicarpus aff. C. brasilianus, Cordaicarpus cerronegrensis e Cordaicarpus truncata com características típicas de plantas pioneiras, sendo a barocoria sua principal síndrome de dispersão com outras síndromes associadas. Abstract in english The morphological analysis of seeds has been an important subject in modern ecological studies, once it provides evidence about the biology and adaptations of the parent plant. However, this kind of study has been restricted to the ecology of modern plants and is rarely used in interpretations of Paleozoic data. From the understanding of dispersal syndromes analysis as an important tool to paleoecological reconstruction, this study provides a first approach using this too (more) l with seeds from the Lower Permian strata of southern Paraná Basin in Rio Grande do Sul. Based on previously classified seeds and using their biological and taphonomic data, the syndrome of dispersal was interpreted, and their placement in successional groups (pioneer, early-successional and later-successional) was suggested. Seven morphospecies were analyzed: Samaropsis gigas, representing a later-successional species living in water bodies with hydrochory as its dispersal syndrome; Samaropsis kurtzii, typical of early-successional species showing anemochory as its dispersal syndrome and living in distal areas in relation to water bodies; Samaropsis aff. S. millaniana, Cordaicarpus aff. C. brasilianus, Cordaicarpus cerronegrensis and Cordaicarpus truncata have typical characteristics of pioneer plants, exhibiting barochory as their primary dispersal syndrome with other syndromes associated.

Souza, Juliane M.; Iannuzzi, Roberto

2012-03-01

88

Dispersal Syndromes of fossil Seeds from the Lower Permian of Paraná Basin, Rio Grande do Sul, Brazil  

Directory of Open Access Journals (Sweden)

Full Text Available The morphological analysis of seeds has been an important subject in modern ecological studies, once it provides evidence about the biology and adaptations of the parent plant. However, this kind of study has been restricted to the ecology of modern plants and is rarely used in interpretations of Paleozoic data. From the understanding of dispersal syndromes analysis as an important tool to paleoecological reconstruction, this study provides a first approach using this tool with seeds from the Lower Permian strata of southern Paraná Basin in Rio Grande do Sul. Based on previously classified seeds and using their biological and taphonomic data, the syndrome of dispersal was interpreted, and their placement in successional groups (pioneer, early-successional and later-successional) was suggested. Seven morphospecies were analyzed: Samaropsis gigas, representing a later-successional species living in water bodies with hydrochory as its dispersal syndrome; Samaropsis kurtzii, typical of early-successional species showing anemochory as its dispersal syndrome and living in distal areas in relation to water bodies; Samaropsis aff. S. millaniana, Cordaicarpus aff. C. brasilianus, Cordaicarpus cerronegrensis and Cordaicarpus truncata have typical characteristics of pioneer plants, exhibiting barochory as their primary dispersal syndrome with other syndromes associated.A Análise morfológica das sementes tem sido um importante objeto em estudos ecológicos modernos, uma vez que fornece evidências sobre a biologia e as adaptações das plantas-mãe de sementes. Entretanto, este tipo de estudo tem sido restrito a ecologia de plantas modernas e é raramente utilizado em interpretações de dados paleozóicos. A partir do entendimento da análise das sindromes de dispersão como uma importante ferramenta para reconstruções paleoecológicas, este estudo oferece uma primeira abordagem utilizando essa ferramenta com sementes do Permiano Inferior do Sul da Bacia do Paraná, no Rio Grande do Sul. Baseado em sementes previamente classificadas e utilizando seus dados biológicos e tafonômicos, a síndrome de dispersão foi interpretada, e a classificação das sementes nos grupos successionais (pioneira, secundária inicial ou secundária tardia) foi sugerida. Sete morfoespécies foram analisadas: Samaropsis gigas, representando uma espécie de secundária-tardia, vivendo próximo a corpos d'água, com síndrome de dispesão hidrocórica; Samaropsis kurtzii, típica espécie de sucessão secundária inicial, apresentando a anemocoria como síndrome de dispersão e habitando áreas distantes em relação a corpos d'água; Samaropsis aff. S. millaniana, Cordaicarpus aff. C. brasilianus, Cordaicarpus cerronegrensis e Cordaicarpus truncata com características típicas de plantas pioneiras, sendo a barocoria sua principal síndrome de dispersão com outras síndromes associadas.

Juliane M. Souza; Roberto Iannuzzi

2012-01-01

89

Petrographic characteristics and depositional conditions of Permian coals of Pench, Kanhan, and Tawa Valley Coalfields of Satpura Basin, Madhya Pradesh, India  

Energy Technology Data Exchange (ETDEWEB)

This paper attempts to characterize the coals of Satpura Gondwana basin using a large number of pillar coal samples drawn from the working coal mines of Pench, Kanhan, and Tawa (Pathakhera) Valley Coalfields of this basin. This westernmost Gondwana basin of Peninsular India is graben/half-graben type and occupies an area of 12000 km{sup 2} with sedimentary fills (>5000 m) ranging in age from Permian to Cretaceous. The Barakar Formation (Permian) is exclusively coal-bearing with a total coal reserve of nearly 2000 Mt. The results show that the coals of this basin are equally rich in inertinite (22.8-58.7%, 24.5-62.0% mmf basis) and vitrinite (24.4-52.4%, 24.4-56.0% mmf basis). The concentration of liptinite ranges from 8.8% to 23.2% (9.0-26.0% mmf basis). The dominant microlithotypes of these coals are inertite and vitrite with comparatively low concentrations of vitrinertite and clarite. The vitrinite reflectance (Rom% values) suggests that the Pench Valley (0.30-0.58%) coals are subbituminous C to high volatile C bituminous in rank, while the Kanhan and Tawa Valley coals (0.52-0.92%) are subbituminous A to high volatile A bituminous in rank. The localized enhancement of rank in the latter two basins has been attributed to the extraneous heat flow from deep-seated igneous intrusions in the basin. The microlithotype composition of these coals is suggestive of their evolution in limno-telmatic zones, under fluvio-lacustrine control with the development of upper deltaic and lower deltaic conditions near the fresh water lacustrines. The floral input is characteristic of forest swamps with intermittent floods, leading to the development of reed moor and open moor facies, particularly in the Pench Valley basin. The Gelification Index (GI) and Tissue Preservation Index (TPI) are suggestive of terrestrial origin with high tree density. Further, moderately high GI and exceedingly high telovitrinite based TPI along with high ash content, particularly for the coals of Kanhan and Tawa Valley Coalfields, are indicative of the recurrence of drier conditions in the forested swamps. Furthermore, lateral variation in TPI values is indicative of increase in the rate of subsidence vis-a-vis depth of the basin from east to west (Pench to Tawa Valley Coalfield). The Ground Water Index (GWI) suggests that these coals have evolved in mires under ombotrophic to mesotrophic hydrological conditions. The Vegetation Index (VI) values are indicative of the dominance of herbaceous plants in the formation of Pench Valley coals and comparatively better forest input in the formation of Kanhan and Tawa Valley coals.

Singh, Mahendra P.; Shukla, R. Rakesh [Department of Geology, Banaras Hindu University, Varanasi- 221 005 (India)

2004-08-10

90

Depositional setting, petrology and chemistry of Permian coals from the Parana Basin: 2. South Santa Catarina Coalfield, Brazil  

Energy Technology Data Exchange (ETDEWEB)

In Brazil economically important coal deposits occur in the southern part of the Parana Basin, where coal seams occur in the Permian Rio Bonito Formation, with major coal development in the states of Rio Grande de Sul and Santa Catarina. The current paper presents results on sequence stratigraphic interpretation of the coal-bearing strata, and petrological and geochemical coal seam characterization from the South Santa Catarina Coalfield, Parana Basin. In terms of sequence stratigraphic interpretation the precursor mires of the Santa Catarina coal seams formed in an estuarine-barrier shoreface depositional environment, with major peat accumulation in a high stand systems tract (Pre-Bonito and Bonito seams), a lowstand systems tract (Ponta Alta seam, seam A, seam B) and a transgressive systems tract (Irapua, Barro Branco and Treviso seams). Seam thicknesses range from 1.70 to 2.39 m, but high proportions of impure coal (coaly shale and shaley coal), carbonaceous shale and partings reduce the net coal thickness significantly. Coal lithoypes are variable, with banded coal predominant in the Barro Branco seam, and banded dull and dull coal predominantly in Bonito and Irapua seams, respectively. Results from petrographic analyses indicate a vitrinite reflectance range from 0.76 to 1.63 %Rrandom (HVB A to LVB coal). Maceral group distribution varies significantly, with the Barro Branco seam having the highest vitrinite content (mean 67.5 vol%), whereas the Irapua seam has the highest inertinite content (33.8 vol%). Liptinite mean values range from 7.8 vol% (Barro Branco seam) to 22.5 vol% (Irapua seam). Results from proximate analyses indicate for the three seams high ash yields (50.2 - 64.2 wt.%). Considering the International Classification of in-Seam Coals, all samples are in fact classified as carbonaceous rocks (> 50 wt.% ash). Sulfur contents range from 3.4 to 7.7 wt.%, of which the major part occurs as pyritic sulfur. Results of X-ray diffraction indicate the predominance of quartz and kaolinite (also pyrite). Gypsum, gibbsite, jarosite and calcite were also identified in some samples. Feldspar was noted but is rare. The major element distribution in the three seams (coal basis) is dominated by SiO{sub 2} (31.3 wt.%, mean value), Al{sub 2}O{sub 3} (14.5 wt.%, mean value) and Fe{sub 2}O{sub 3} (6.9 wt.%, mean value). Considering the concentrations of trace elements that are of potential environmental hazards the Barro Branco, Bonito and Irapua seams (coal base) are significantly enriched in Co (15.7 ppm), Cr (54.5 ppm), Li (59.3 ppm), Mn (150.4 ppm), Pb (58.0 ppm) and V (99.6 ppm), when compared to average trace elements contents reported for U. S. coals. Hierarchical cluster analysis identified, based on similarity levels, three groups of major elements and seven groups of trace elements. Applying discriminant analyses using trace and major element distribution, it could be demonstrated that the three seams from Santa Catarina show distinct populations in the discriminant analyses plots, and also differ from the coals of Rio Grande do Sul analyzed in a previous study. (author)

Kalkreuth, W.; Mexias, A.; Balbinot, M.; Levandowski, J. [Instituto de Geociencias, UFRGS, Porto Alegre (Brazil); Holz, M. [Inst. de Geociencias, UFBA, Salvador, Bahia (Brazil); Willett, J.; Finkelman, R. [U.S. Geological Survey, Reston, VA (United States); Burger, H. [Freie Universitaet Berlin, Geoinformatik, (Germany)

2010-12-01

91

Permian chronostratigraphy in Kansas  

Energy Technology Data Exchange (ETDEWEB)

Correlations between the type Permian System of Russia and North American strata have been difficult for decades because of biostratigraphic and nomenclatural confusion. Consequently, a standard Permian section was established in west Texas that is widely accepted throughout North America. Series of the North American standard section are, in ascending order, Wolfcampian, Leonardian, Guadalupian, and Ochoan. This nomenclature was adopted for usage in Kansas in 1951, but was later abandoned in favor of local terminology. However, direct biostratigraphic correlations between Kansas and the west Texas standard section have now been firmly established, and local chronostratigraphic names, i.e., Big Blue, Lyon, Geary, Cimarron, and Custer, have not been widely accepted. The Kansas Geological Survey has now readopted usage of the Wolfcampian Series for rocks of the Admire, Council Grove, and Chase Groups; the Leonardian Series for rocks of the Summer and Nippewalla Groups; and the Guadalupian Series for rocks of the Whitehorse, Day Creek, and Big Basin Formations. The Wolfcampian Series in Kansas (and elsewhere in North America) contains post-Virgilian (latest Carboniferous) strata that predate the classical Permian System of the Russian type section. Consequently, the Pennsylvanian/Permian boundary will probably have to be raised stratigraphically to conform to global usage.

Baars, D.L. (Univ. of Kansas, Lawrence (USA))

1990-08-01

92

The age of the Tunas formation in the Sauce Grande basin-Ventana foldbelt (Argentina): Implications for the Permian evolution of the southwestern margin of Gondwana  

Science.gov (United States)

New SHRIMP radiogenic isotope dating on zircons in tuffs (280.8 ± 1.9 Ma) confirms the Early Permian (Artinskian) age of the uppermost section of the Tunas Formation. Tuff-rich levels in the Tunas Formation are exposed in the Ventana foldbelt of central Argentina; they are part of a deltaic to fluvial section corresponding to the late overfilled stage of the Late Paleozoic Sauce Grande foreland basin. Recent SHRIMP dating of zircons from the basal Choiyoi volcanics exposed in western Argentina yielded an age of 281.4 ± 2.5 Ma (Rocha-Campos et al., 2011). The new data for the Tunas tuffs suggest that the volcanism present in the Sauce Grande basin can be considered as the distal equivalent of the earliest episodes of the Choiyoi volcanism of western Argentina. From the palaeoclimatic viewpoint the new Tunas SHRIMP age confirms that by early Artinskian glacial conditions ceased in the Sauce Grande basin and, probably, in adajacent basins in western Gondwana.

López-Gamundí, Oscar; Fildani, Andrea; Weislogel, Amy; Rossello, Eduardo

2013-08-01

93

Illite/Smectite diagenesis in the NanXiang, Yitong, and North China Permian-carboniferous basins: Application to petroleum exploration in China  

Energy Technology Data Exchange (ETDEWEB)

The NanXiang basin in Henan Province and the Yitong basin in Jilin Province, located in the eastern part of China, are composed mainly of Tertiary nonmarine clastic sequences that thicken to more than 4000-5000 m. The North China Permian-Carboniferous basin consists of Permian-Carboniferous systems composed of marine and nonmarine coal-bearing sequences. Clay diagenesis in these basins was studied by systematic x-ray diffraction analysis. The clay mineralogy consists of illite, smectite, mixed-layered illite/smectite (I/S), kaolinite, and chlorite. The major clay reaction is the illitization of smectite with depth and temperature. The reactions generally involve discrete smectite stage to smectite, plus the randomly interstratified I/S (R = 0 in the Reichweite nomenclature), followed by the first rapid change (1) to the ordered I/S of short-range stacking (R = 1) and the second rapid change (11) to the metastable stage (with the ordered I/S of long-range stacking-R {ge}3). The first rapid change leads to the appearance of I/S-ordered I/S and disappearance of discrete smectite. The proportion of smectite layers (Ps) in the I/S in the metastable stage remained unchanged (15-20%) over a thick burial interval. The discrete illite stage finally occurs in highly mature areas. Potassium-feldspar (K-feldspar) in rocks and K ions in present formation waters are available for the I/S reactions; I/S reactions in these areas responded mainly to temperature. The I/S transition from the randomly interstratified I/S (R = 0) to the ordered I/S occurred at 80-95{degrees}C and coincided with the onset of the oil window in source rocks and with secondary porosity enhancement of sand-stones. Integrating the I/S reactions with thermal histories, hydrological regimes, structure, sedimentation, and sandstone diagenesis of each basin allows formulation of clay diagenetic models for each specific basin.

Xinhua Deng; Youngchuan Sun; Xinrong Lei [China Univ. of Geosciences, Wuhan (China)] [and others

1996-02-01

94

Dolomite, gypsum, and anhydrite in Permian McElroy field, Central Basin platform: genetic and spatial relationships to facies tracts, cyclicity, structure, and pay zones  

Energy Technology Data Exchange (ETDEWEB)

The Permian McElroy field at the eastern margin of the Central Basin platform is part of the giant P.J.W.D.M. field complex. Oil production occurs mainly from the Grayburg Formation, which consists of at least four and possibly five internal sedimentary cycles. Trapping is facilitated by a combination of structure (asymmetrical anticline) and a seal of fine-grained peritidal and supratidal dolostones plugged and overlain by gypsum and anhydrite. Although most oil is located close to the top of the structure, the gross pay zone appears to be subdivided into smaller irregularly shaped pods. The geometry and degree of interconnection of these pods are difficult to predict and may be related to the internal cyclicity as well as to diagenesis and structure. Dolomitization largely enhanced and emplacement of sulfates largely reduced the reservoir quality. Data suggest subhorizontal fluid flow in at least one part of the field during dolomite formation or recrystallization from gypsum-saturated brines. Sulfur and oxygen isotope data of the sulfates scatter from 10.0 to 12.5 /per thousand/ CDT and 10.0 to 14.3 /per thousand/ SMOW, respectively, suggesting precipitation from Late Permian brines and later recrystallization and redistribution accompanied by oxidation of bacterial sulfide, minor mixing with older or younger sulfate, equilibration of isotopically heavier formation waters, or a combination thereof.

Machel, H.G.; Longacre, S.A.

1989-03-01

95

Geoscience/Engineering Characterization of the Interwell Environment in Carbonate Reservoirs Based on Outcrop Analogs, Permian Basin, West Texas and New Mexico.  

Energy Technology Data Exchange (ETDEWEB)

The objective of this project is to investigate styles of reservoir heterogeneity found in low permeability pelleted wackestone/packstone facies and mixed carbonate/clastic facies found in Permian Basin reservoirs by studying similar facies exposed in the Guadalupe Mountains. Specific objectives for the outcrop study include construction of a stratigraphic framework, petrophysical quantification of the framework, and testing the outcrop reservoir model for effects of reservoir heterogeneity on production performance. Specific objectives for the subsurface study parallel objectives for the outcrop study. Subsurface Activities - We continue to prepare two final reports that summarize research results of the South Cowden Field study. One report summarizes results of the petrophysical characterization research, and one summarizes results of the fluid-flow modeling research. Outcrop Activities - We also continue to prepare the final report, which summarizes the research results of the Grayburg outcrop reservoir study.

Lucia, Jerry F.; Kerans, Charles

1997-05-29

96

Geoscience/Engineering Characterization of the Interwell Environment in Carbonate Reservoirs Based on Outcrop Analogs, Permian Basin, West Texas and New Mexico.  

Energy Technology Data Exchange (ETDEWEB)

The objective of this project is to investigate styles of reservoir heterogeneity found in low permeability pelleted wackestone/packstone facies and mixed carbonate/clastic facies found in Permian Basin reservoirs by studying similar facies exposed in the Guadalupe Mountains. Specific objectives for the outcrop study include construction of a stratigraphic framework, petrophysical quantification of the framework, and testing the outcrop reservoir model for effects of reservoir heterogeneity on production performance. Specific objectives for the subsurface study parallel objectives for the outcrop study. Subsurface Activities - We continue to prepare two final reports that summarize research results of the South Cowden Field study. One report summarizes results of the petrophysical characterization research, and one summarizes results of the fluid-flow modeling research. Outcrop Activities - We also continue to prepare the final report, which summarizes the research results of the Grayburg outcrop reservoir study.

Lucia, Jerry F.; Kerans, Charles

1997-05-19

97

Strike variability of carbonate platform margin stratal architecture and cycle stacking patterns: Outcrop and seismic examples from lower Permian depositional sequences of the Permian Basin, U. S. A  

Energy Technology Data Exchange (ETDEWEB)

Strike variability in stratal architecture, cycle stacking patterns and facies differentiation within sequences exemplifies the potential for differential stratigraphic response of platforms to eustasy. Variability exists within base-level cycles of several scales within a compound stratigraphic hierarchy, though the causes may vary among different scales. Cross-sections from outcrops in the Sierra Diablo document the framework and stacking pattern of 3rd-order sequences (HFS), including: two progradational middle Wolfcampian HFS (mW1-2), one backstepped upper Wolfcampian HFS (uW1), one progradational lower Leonardin HFS (L1), aggradational middle (L2) and upper Leonardian HFS (L3), three progradatic upper Leonardian HFS (L4-6), and two backstepped, aggradational upper Leonardian HFS (L7-8). Seismic lines from the northern Delaware and Midland Basins and San Simon Channel area document the regional consistency of 3rd-order sequence stacking patterns (a response to eustasy), but show variability related to local subsidence, antecedent topography (owing to deeper structures and platform margin erosion), windward vs. leeward facing, and siliciclastic sediment supply. Sequences L2 and L3 appear to exhibit the greatest variability in stacking pattern. Strike variability in 4th/5th-order cycle stacking patterns within 3rd-order sequences as studied in outcrop is greatest in sequences L2 and L3, in which headland-bight margin trends are developed on a lateral scale of 1-2 miles. Aggrational to backstepping reef-margin facies with steep ([le]35[degrees]) foreslopes developed along headlands. Mudstones abut these margin facies abruptly along headlands and may contain megabreccias at the toe-of-slope. More gently sloping (10-15[degrees]) [open quotes]ramp[close quotes] margin strata composed of fusulinid packstones characterize bights.

Fitchen, W.M. (Univ. of Texas, Austin, TX (United States))

1996-01-01

98

Petrology and chemistry of Permian coals from the Parana Basin: 1. Santa Terezinha, Leao-Butia and Candiota Coalfields, Rio Grande do Sul, Brazil  

Energy Technology Data Exchange (ETDEWEB)

The current paper presents results on petrological and geochemical coal seam characterization in Permian coal-bearing strata from the Parana Basin, southern Brazil. Sequence stratigraphic analysis shows that peat accumulation in Permian time was closely linked to transgressive/regressive cycles, with peat accumulation occurring in a predominantly back barrier/lagoonal setting. Coal petrographic analysis indicates subbituminous coals at Candiota and Leao-Butia and high volatile bituminous coals at Santa Terezinha, where locally the coal seams are thermally altered by volcanic intrusions. Petrographic composition is highly variable, with seams at Candiota and Santa Terezinha frequently enriched in inertinite. Chemical analyses indicate that all coals are mineral matter-rich (mean 49.09 wt.%), with SiO{sub 2} and Al{sub 2}O{sub 3} dominating as determined by ICP-AES. Quartz is also the predominant mineral detected by X-ray diffraction, where it is associated with feldspar, kaolinite and hematite and iron-rich carbonates. The results from Scanning Electron Microscopy are broadly consistent with the bulk chemical and mineralogical analysis. Quartz and clays are common in all samples analyzed. Other minerals observed were, amongst others, carbonates (calcite, siderite, ankerite), pyrite, monazite, kaolinite, barite, sphalerite, rutile and quartz of volcanic origin. The distribution of trace elements is well within the range typical for coal basins of other areas despite the fact that the Parana Basin coals are very high in ash yields. The average concentrations for elements of environmental concern (As, B, Be, Cd, Co, Cr, Cu, Hg, Li, Mn, Mo, Ni, Pb, Sb, Se, Tl, U, V, Zn) are similar to or less than the mean values for U.S. coal. However, considered on an equal energy basis, Parana Basin coals will produce in combustion 5 to 10 times the amount of most elements compared to an equal weight US coal. Concentrations of major and trace elements, such as Fe, B and S, appear to be controlled by depositional setting, with increasing values in coal seams overlain by brackish/marine strata. Hierarchical cluster analysis identified three groups of major minerals and seven groups of trace elements based on similarity levels. On a regional scale, the coalfields can be separated by the differences in rank (Candiota and Leao-Butia versus Santa Terezinha) and by applying discriminant analysis based on 4 trace elements (Li, As, Sr, Sb). Highest Rb and Sr values occur at Candiota and are linked to syngenetic volcanism of the area, whereas high Y and Sr values at Santa Terezinha can be related to the frequent diabase intrusions in that area. (author)

Kalkreuth, W.; Holz, M.; Kern, M.; Mexias, A.; Silva, M.B. [Instituto de Geociencias, UFRGS, Av. Bento Goncalves, 9500, 91501-970 Porto Alegre, RS (Brazil); Machado, G. [Instituto de Quimica, UFRGS, Av. Bento Goncalves, 9500, 91501-970 Porto Alegre, RS (Brazil); Willett, J.; Finkelman, R. [U.S. Geological Survey, Mail Stop 956, Reston, VA 20192 (United States); Burger, H. [Freie Universitaet Berlin-Geoinformatik-Malteserstr. 74-100, 12249 Berlin (Germany)

2006-08-01

99

Depositional record of tidal-flat sedimentation in the Permian coal measures of Central India: Barakar Formation, Mohpani coalfield, Satpura Gondwana basin  

Energy Technology Data Exchange (ETDEWEB)

The Permian Barakar Formation in the Mohpani coalfield, Satpura Gondwana basin, is composed of three broad lithologies that occur repetitively and are iterdigitated: (1) several metres thick coarse- to medium-grained sandstone bodies with scoured bases, (2) 5-20 m thick medium- to fine-grained sandstone bodies and (3) 5-20 m thick mudstone-dominated packages with variable proportions of centimetre- to decimetre-scale, fine- to medium-grained sandstone, carbonaceous shale and coal. The Barakar strata were previously interpreted as deposits of braided rivers and associated inter-channel flood basin in a continental setting. However, this study recognizes signatures of tidal current from the mudstone-dominated packages implying marine influence during Barakar sedimentation. The mudstone-dominated sediment bodies are the focus of this paper and comprise of three lithofacies that bear imprints of tidal processes during Barakar sedimentation: (1) heterolith, (2) sandstone, and (3) coal-carbonaceous shale, which alternate with one another within individual bodies. The coal-carbonaceous shale facies represent supratidal marsh environment.

Chakraborty, C.; Ghosh, S.K.; Chakraborty, T. [Indian State Institute, Kolkata (India). Geological Studies Unit

2003-10-01

100

A Resource Assessment Of Geothermal Energy Resources For Converting Deep Gas Wells In Carbonate Strata Into Geothermal Extraction Wells: A Permian Basin Evaluation  

Energy Technology Data Exchange (ETDEWEB)

Previously conducted preliminary investigations within the deep Delaware and Val Verde sub-basins of the Permian Basin complex documented bottom hole temperatures from oil and gas wells that reach the 120-180C temperature range, and occasionally beyond. With large abundances of subsurface brine water, and known porosity and permeability, the deep carbonate strata of the region possess a good potential for future geothermal power development. This work was designed as a 3-year project to investigate a new, undeveloped geographic region for establishing geothermal energy production focused on electric power generation. Identifying optimum geologic and geographic sites for converting depleted deep gas wells and fields within a carbonate environment into geothermal energy extraction wells was part of the project goals. The importance of this work was to affect the three factors limiting the expansion of geothermal development: distribution, field size and accompanying resource availability, and cost. Historically, power production from geothermal energy has been relegated to shallow heat plumes near active volcanic or geyser activity, or in areas where volcanic rocks still retain heat from their formation. Thus geothermal development is spatially variable and site specific. Additionally, existing geothermal fields are only a few 10’s of square km in size, controlled by the extent of the heat plume and the availability of water for heat movement. This plume radiates heat both vertically as well as laterally into the enclosing country rock. Heat withdrawal at too rapid a rate eventually results in a decrease in electrical power generation as the thermal energy is “mined”. The depletion rate of subsurface heat directly controls the lifetime of geothermal energy production. Finally, the cost of developing deep (greater than 4 km) reservoirs of geothermal energy is perceived as being too costly to justify corporate investment. Thus further development opportunities for geothermal resources have been hindered. To increase the effective regional implementation of geothermal resources as an energy source for power production requires meeting several objectives. These include: 1) Expand (oil and gas as well as geothermal) industry awareness of an untapped source of geothermal energy within deep permeable strata of sedimentary basins; 2) Identify and target specific geographic areas within sedimentary basins where deeper heat sources can be developed; 3) Increase future geothermal field size from 10 km2 to many 100’s km2 or greater; and 4) Increase the productive depth range for economic geothermal energy extraction below the current 4 km limit by converting deep depleted and abandoned gas wells and fields into geothermal energy extraction wells. The first year of the proposed 3-year resource assessment covered an eight county region within the Delaware and Val Verde Basins of West Texas. This project has developed databases in Excel spreadsheet form that list over 8,000 temperature-depth recordings. These recordings come from header information listed on electric well logs recordings from various shallow to deep wells that were drilled for oil and gas exploration and production. The temperature-depth data is uncorrected and thus provides the lower temperature that is be expected to be encountered within the formation associated with the temperature-depth recording. Numerous graphs were developed from the data, all of which suggest that a log-normal solution for the thermal gradient is more descriptive of the data than a linear solution. A discussion of these plots and equations are presented within the narrative. Data was acquired that enable the determination of brine salinity versus brine density with the Permian Basin. A discussion on possible limestone and dolostone thermal conductivity parameters is presented with the purpose of assisting in determining heat flow and reservoir heat content for energy extraction. Subsurface maps of temperature either at a constant depth or within a target geothermal reservoir are discusse

Erdlac, Richard J., Jr.

2006-10-12

 
 
 
 
101

Deposition of the Early to Late Permian Whitehill Formation during a sea-level highstand in a juvenile foreland basin  

Energy Technology Data Exchange (ETDEWEB)

The black, laminated, carbonaceous shales of the Whitehill Formation were deposited in a very young, underfilled foreland basin under anoxic bottom conditions. A sea-level highstand, basin tectonics, and climate were the controlling factors - interplay of which resulted in bounding conditions for organic-rich mud deposition during a specific time slot in the history of the basin. Coal-forming environments along the steep palaeo-eastern basin margin were the source of mud and organic matter transported as fresh-water plumes in an offshore direction during episodic flooding and erosion of the organic-rich deposits. Air-borne volcanic ash deposited together with the muds as well as in discrete layers was derived from a tectonic arc in the palaeo-west. The high concentration of organic matter in the water body and the restricted oceanic circulation in the morphologically complex basin created anoxia in the water column. Preservation of organic matter in the absence of benthonic fauna was high. Less anoxic conditions prevailed in the shallow marginal regions where deposition of siltstone and carbonate rocks interbedded with the black shales took place. Continuous inflow of fresh-water plumes in the restricted basin progressively caused brackish conditions suitable for the proliferation of aquatic fauna. 67 refs., 10 figs., 1 tab.

Visser, J.N.J. (Orange Free State University, Bloemfontein (South Africa). Dept. of Geology)

1992-12-01

102

Suspension- and current-deposit reservoirs in the Delaware basin: Trends and cycles in siltstones of the Permian Bone Spring Limestone  

Energy Technology Data Exchange (ETDEWEB)

Cores show that siltstone to very fine-grained sandstone oil reservoirs within the Permian Bone Spring Limestone are composed of submillimeter- to centimeter-thick sedimentation laminae. Blanketing of small-scale topography suggests that the laminae were deposited over wide areas as sediment settled vertical to the sea floor. Superimposed on the event laminae, were (1) background sedimentation of dolomitic, organic-rich, mudstone, (2) invertebrate burrowing, and (3) reworking by gentle bottom currents. Currents produced wispy ripply bedding and starved ripple forms that were draped by later deposits. Paleoflow was subparallel to the basin margin. Several sedimentation patterns occur within the formation. Three clastic intervals 25-50-m thick are interbedded with dolomitic mudstones of similar thickness. The clastic intervals are composed of three to six siltstone beds, each up to 25-m thick. Upsection within the beds increases in event-laminae, thickness, bioturbation, and current reworking. Other reports have suggested that these are turbidite-fan deposits, but locally, paleocurrent orientations and the lack of diagnostic assemblages and sequences of sedimentary structures argue against this interpretation. Rather, some of these deposits compare favorably with the few existing sedimentologic descriptions of Quaternary dust storm deposition in marine basins. The siltstone beds may also record deflation of the exposed adjacent shelf during lowered sea level. Very fine grain size and extensive carbonate cementation produce 5-10 pd permeability and 4-15% porosity. Sedimentary laminations cause significantly reduced vertical permeability where they are not disrupted by bioturbation, but permeability may be enhanced by natural fractures. Some reservoir thickenings are attributed to the formation of giant ripples by bottom currents, dictating a different exploration rationale than the turbidite-fan model.

Lorenz, J.C. (Sandia National Lab., Albuquerque, NM (USA)); Brooks, L.L. (Harvey E Yates Petroleum Co., Roswell, NM (USA))

1990-05-01

103

A Middle Permian-Middle Triassic accretionary complex and a Late Triassic foredeep basin: Forerunners of an Indosinian (Late Triassic) thrust complex in the Thailand-Malaysia border area  

Science.gov (United States)

The Semanggol Formation of NW Peninsular Malaysia is a Middle Permian-Late Triassic sequence of predominantly radiolarian chert, sandstone and mudstone (including turbidites), and conglomerate. The belt of country occupied by this unit extends into Thailand where various names including Na Thawi formation have been applied to its correlatives. Fossil evidence, particularly radiolarian, has established its age but also revealed that it is tectonically complex, with numerous out-of-sequence slices interpreted here to be caused by thrusting.The model proposed here involves, initially, in the Middle Permian, accumulation in the oceanward part of an accretionary complex as Palaeotethys began subducting beneath Indochina/East Malaya. This regime, it is proposed, continued until about the end of the Middle Triassic when Sibumasu collided with Indochina/East Malaya bringing an end to subduction. But as crustal shortening continued into the Late Triassic a foredeep basin formed in front of the now-inactive subduction zone and accretionary complex, and the youngest part of the Semanggol Formation was deposited. During this final stage the whole package of rocks comprising those in the accretionary complex and those deposited in the foredeep basin underwent lateral compression resulting in a thrust complex.The Semanggol Formation and its Thailand correlatives occupy part of a N-S belt of imbricately-thrust, deeper-water, sediments which include slope-deposited Carboniferous and Lower Permian beds. That belt is interpreted as a series of thrust slices juxtaposing rocks of different ages, referred to here as the Songkhla-Semanggol terrane. Its western boundary is a N-S line of inferred thrusting which coincides with a major westward facies change to platform carbonates of Middle Permian to Late Triassic age, called here the Rattaphum-Kodiang tectonic line.

Ridd, Michael F.

2013-10-01

104

Radiometric dating of Ochoan (Permian) evaporites, WIPP [Waste Isolation Pilot Plant] site, Delaware Basin, New Mexico, USA  

International Nuclear Information System (INIS)

[en] We have attempted radiometric dating of halide-sulfate salts and clay minerals from the Delaware Basin, New Mexico, USA, as part of geochemical study of the stability of the evaporite sequence at the WIPP (Waste Isolation Pilot Plant - a US DOE facilty) site. We undertook this dating to determine: (1) primary age of evaporite genesis or time(s) of recrystallization; (2) if previously undated evaporite minerals (leonite, polyhalite, kieserite) give useful data; and (3) if the detrital clay minerals have been radiometrically reset at any time following their incorporation into the evaporite medium. We have shown earlier that polyhalites can indeed be successfully dated by the K-Ar method, and once corrections are applied for admixed halide minerals, dates of 210-230 Ma for the Delaware Basin are obtained. Rb-Sr isochrons from early stage sylvites-polyhalites- anhydrites yield 220 +- 10 Ma, even when some sylvites yield lower K-Ar dates due to loss of *40-Ar. K-Ar dates on leonites and kieserities are also low due to *40-Ar loss, but their Rb-Sr dates are higher. Detrital clay minerals from the Delaware Basin collectively yield a highly scattered isochron (390 +- 77 Ma), but samples from a local area, such as the WIPP Site, give a much better age of 428 +- 7 Ma. These dates show that the interaction between the clay minerals and the evaporitic brines was insufficient to reset the clay minerals Rb-Sr systematics. In a related study, we note that a dike emplaced into the evaporite at 34 Ma had only very limited effect on the intruded rocks; contact phenomena were all within 2 m of the dike. All of our geochemical (radio-metric and trace element) studies of the WIPP site argue for preservation of the isotopic and chemical integrity of the major minerals for the past 200 Ma

1986-01-01

105

Radiometric dating of Ochoan (Permian) evaporites, WIPP (Waste Isolation Pilot Plant) site, Delaware Basin, New Mexico, USA  

Energy Technology Data Exchange (ETDEWEB)

We have attempted radiometric dating of halide-sulfate salts and clay minerals from the Delaware Basin, New Mexico, USA, as part of geochemical study of the stability of the evaporite sequence at the WIPP (Waste Isolation Pilot Plant - a US DOE facilty) site. We undertook this dating to determine: (1) primary age of evaporite genesis or time(s) of recrystallization; (2) if previously undated evaporite minerals (leonite, polyhalite, kieserite) give useful data; and (3) if the detrital clay minerals have been radiometrically reset at any time following their incorporation into the evaporite medium. We have shown earlier that polyhalites can indeed be successfully dated by the K-Ar method, and once corrections are applied for admixed halide minerals, dates of 210-230 Ma for the Delaware Basin are obtained. Rb-Sr isochrons from early stage sylvites-polyhalites- anhydrites yield 220 +- 10 Ma, even when some sylvites yield lower K-Ar dates due to loss of *40-Ar. K-Ar dates on leonites and kieserities are also low due to *40-Ar loss, but their Rb-Sr dates are higher. Detrital clay minerals from the Delaware Basin collectively yield a highly scattered isochron (390 +- 77 Ma), but samples from a local area, such as the WIPP Site, give a much better age of 428 +- 7 Ma. These dates show that the interaction between the clay minerals and the evaporitic brines was insufficient to reset the clay minerals Rb-Sr systematics. In a related study, we note that a dike emplaced into the evaporite at 34 Ma had only very limited effect on the intruded rocks; contact phenomena were all within 2 m of the dike. All of our geochemical (radio-metric and trace element) studies of the WIPP site argue for preservation of the isotopic and chemical integrity of the major minerals for the past 200 Ma.

Brookins, D.G.; Lambert, S.J.

1986-01-01

106

Coal petrology of coal seams from the Leao-Butia Coalfield, Lower Permian of the Parana Basin, Brazil - Implications for coal facies interpretations  

Energy Technology Data Exchange (ETDEWEB)

In the Leao-Butia Coalfield, Rio Grande do Sul the coal seams occur in the Rio Bonito Formation, Guata Group, Tubarao Supergroup of the Parana Basin, Brazil and are of Permian (Artinskian-Kungurian) age. This study is the first detailed investigation on the coal petrographic characterization of the coal-bearing sequence in relation to the depositional settings of the precursor mires, both in terms of whole seam characterization and in-seam variations. The study is based on the analyses of nine coal seams (I2, CI, L4, L3, L2, L1, S3, S2, S1), which were selected from core of borehole D-193, Leao-Butia and represent the entire coal-bearing sequence. The interpretation of coal facies and depositional environment is based on lithotype, maceral and microlithotype analyses using different facies-critical petrographic indices, which were displayed in coal facies diagrams. The seams are characterized by the predominance of dull lithotypes (dull, banded dull). The dullness of the coal is attributed to relatively high mineral matter, inertinite and liptinite contents. The petrographic composition is dominated by vitrinite (28-70 vol.% mmf) and inertinite (> 30 vol.% mmf) groups. Liptinite contents range from 7 to 30 vol.% (mmf) and mineral matter from 4-30 vol.%. Microlithotypes associations are dominated by vitrite, duroclarite, carbominerite and inertite. It is suggested that the observed vertical variations in petrographic characteristics (lithotypes, microlithotypes, macerals, vitrinite reflectance) were controlled by groundwater level fluctuations in the ancient mires due to different accommodation/peat accumulation rates. Correlation of the borehole strata with the general sequence-stratigraphical setting suggests that the alluvial fan system and the coal-bearing mudstone succession are linked to a late transgressive systems tract of sequence 2. Based on average compositional values obtained from coal facies diagrams, a deposition in a limno-telmatic to limnic coal facies is suggested. (author)

Silva, M.B. [Laboratorio de Oceanografia Geologica, Departamento de Geociencias, Fundacao Universidade Federal do Rio Grande, FURG, Av. Italia km 08, Campus Carreiros, 96201-900, Rio Grande, RS (Brazil); Kalkreuth, W.; Holz, M. [Instituto de Geociencias, UFRGS, Av. Bento Goncalves, 9500 91501-970 Porto Alegre, RS (Brazil)

2008-02-01

107

Geoscience/engineering characterization of the interwell environment in carbonate reservoirs based on outcrop analogs, Permian Basin, West Texas and New Mexico. Quarterly report, January 1--April 30, 1996  

Energy Technology Data Exchange (ETDEWEB)

The objective of this project is to investigate styles of reservoir heterogeneity found in low-permeability pelleted wackestone/packstone facies and mixed carbonate/clastic facies found in Permian Basin reservoirs by studying similar facies exposed in the Guadalupe Mountains. Specific objectives for the outcrop study include construction of a stratigraphic framework, petrophysical quantification of the framework, and testing the outcrop reservoir model for effects of reservoir heterogeneity on production performance. Specific objectives for the subsurface study parallel objectives for the outcrop study.

Lucia, F.J.; Kerans, C.

1996-04-30

108

Geoscience/engineering characterization of the interwell environment in carbonate reservoirs based on outcrop analogs, Permian Basin, West Texas and New Mexico. Quarterly technical progress report, April 1, 1995--June 1, 1995  

Energy Technology Data Exchange (ETDEWEB)

The objective of this project is to investigate styles of reservoir heterogeneity that occur in low permeability pelleted wackestone/packstone facies and mixed carbonate/clastic facies found in Permian Basin reservoirs by studying similar facies exposed in the Guadalupe mountains. Specific objectives for the outcrop study include construction of a stratigraphic framework, petrophysical quantification of the framework, and testing the outcrop reservoir model for effects of reservoir heterogeneity on production performance. Specific objectives for the subsurface study parallel objectives for the outcrop study. Technical progress is reported for outcrop activities and subsurface activities.

Lucia, F.J.; Kerans, C.

1995-09-01

109

Variable eruptive styles in an ancient monogenetic volcanic field: examples from the Permian Levín Volcanic Field (Krkonoše Piedmont Basin, Bohemian Massif)  

Directory of Open Access Journals (Sweden)

Full Text Available The Permian pyroclastic deposits of the Levín Volcanic Field within the Krkonoše Piedmont Basin were studied in terms of volcanology. Pyroclastic rocks are exposed in two quarries and the study was supported with the 30 m deep borehole K1 penetrating these rocks. The pyroclastic rocks are altered but preserved textures enabled reconstruction of eruptive styles. The volcanic sequence exposed in the abandoned Hv?zda quarry starts with a phreato-Strombolian pyroclastic rocks rich in basaltic scoriae, cuspate glass shards, armoured- and accretionary lapilli overlain with mafic lava. Subsequent activity was phreatomagmatic in style and produced fall-out of accretionary lapilli and accumulation of base surge deposits. Overlying subhorizontally bedded matrix-supported pyroclastic deposits are rich in scoria and contain spindle-shaped bombs. These rocks are interpreted as mafic pyroclastic flow deposits related to Strombolian eruptions. A similar succession capped by scoriaceous fall-out deposit was documented in the K1 borehole. A coherent mafic volcanic rock (lava or sill) terminates the succession exposed in the Hv?zda quarry. Agglutinates at the base of the Studenec quarry were produced during Hawaiian eruptions building up a spatter cone. The cone most probably dammed a stream and created an ephemeral lake. Increasing influence of water on eruptive styles is documented in overlying pyroclastic deposits of phreatomagmatic eruptions. Subsequent lava flowed into the lake. Quenching of the lava resulted in formation of pillows enclosed in hyaloclastite breccia. Further up in the exposure, transition of pillow lava to massive lava has been recognized. Overlaying pyroclastic deposits are matrix-supported and rich in scoria and spindle-shaped bombs. Similarly to the Hv?zda quarry, these are interpreted as mafic pyroclastic flow deposits. Volcanic activity in the Levín Volcanic Field was characterized by Hawaiian, Strombolian, phreato-Strombolian and phreatomagmatic eruptions accompanying lava effusions and possibly sills emplacement. The lavas were emitted in both subaerial and subaquatic conditions. The character and distribution of volcaniclastic facies suggests existence of several monogenetic volcanoes.

Stárková M; Rapprich V; Breitkreuz Ch

2011-01-01

110

Geoscience/engineering characterization of the interwell environment in carbonate reservoirs based on outcrop analogs, Permian basin, west Texas and New Mexico. Quarterly technical progress report, July 1--September 30, 1995  

Energy Technology Data Exchange (ETDEWEB)

The objective of this project is to investigate styles of reservoir heterogeneity found in low-permeability pelleted wackestone/packstone facies and mixed carbonate/clastic facies found in Permian Basin reservoirs by studying similar facies exposed in the Guadalupe Mountains. Specific objectives for the outcrop study include construction of a stratigraphic framework, petrophysical quantification of the framework, and testing the outcrop reservoir model for effects of reservoir heterogeneity on production performance. Specific objectives for the subsurface study parallel objectives for the outcrop study. Mapping and documenting ooid channel deposits continued through the third quarter. A report on the geological characterization of the South Cowden field has been completed and submitted as the 1995 annual report. An initial simulation model of part of the Moss Unit has been prepared using a simple layering scheme and geostatistical techniques.

Lucia, F.J.; Kerans, C.

1995-12-01

111

TSR versus non-TSR processes and their impact on gas geochemistry and carbon stable isotopes in Carboniferous, Permian and Lower Triassic marine carbonate gas reservoirs in the Eastern Sichuan Basin, China  

Science.gov (United States)

The Palaeozoic and lowermost Mesozoic marine carbonate reservoirs of the Sichuan Basin in China contain variably sour and very dry gas. The source of the gas in the Carboniferous, Permian and Lower Triassic reservoirs is not known for certain and it has proved difficult to discriminate and differentiate the effects of thermal cracking- and TSR-related processes for these gases. Sixty-three gas samples were collected and analysed for their composition and carbon stable isotope values. The gases are all typically very dry (alkane gases being >97.5% methane), with low (PDB showing that it was not solely derived from the oxidation of alkanes. Instead CO2 may partly result from reaction of sour gas with carbonate reservoir minerals, such as Fe-rich dolomite or calcite, resulting in pyrite growth as well as CO2-generation.

Liu, Q. Y.; Worden, R. H.; Jin, Z. J.; Liu, W. H.; Li, J.; Gao, B.; Zhang, D. W.; Hu, A. P.; Yang, C.

2013-01-01

112

SHRIMP chronology of the Magallanes Basin basement, Tierra del Fuego: Cambrian plutonism and Permian high-grade metamorphism/ Geocronología SHRIMP del basamento de la Cuenca de Magallanes, Tierra del Fuego: plutonismo Cámbrico y metamorfismo Pérmico de alto grado  

Scientific Electronic Library Online (English)

Full Text Available Abstract in spanish Cinco nuevas edades radiométricas logradas mediante análisis U-Pb en circón utilizando el SHRIMP, fueron determinadas en gneises y rocas plutónicas foliadas obtenidas desde el fondo de pozos de sondajes en la Cuenca de Magallanes y pertenecientes al denominado Complejo ígneo y Metamór-fico de Tierra del Fuego. En tres de las muestras fueron calculadas edades del Cámbrico Temprano (523±7 Ma, 522±6 Ma y 538±6 Ma), interpretadas como edades de cristalización ígne (more) a de las rocas estudiadas. Un gneis migmatítico presenta 'peaks' de circones heredados de ca. 950-1.100 Ma y de 560-650 Ma además de dos granos de edades de 525 Ma, indicando la participación de material Grenviliano y Brasiliano en el protolito de la migmatita cámbrica. Un gneiss de cordierita-sillimanita-granate presenta una población de circones ígneos de edad cámbrica y otro grupo de circones metamórficos, ricos en U, de edad pérmica, indicando que en el Pérmico un evento metamórfico del alto grado acompañado de anatexis (P=2-3 kbar, T=730-770°C) afectó a rocas ígneas cámbricas y/o a rocas sedimentarias derivadas de ellas. Rocas plutónicas cámbricas/ediacaranas han sido descritas en el NW de Argentina, en los basamentos de la Sierra de la Ventana y del Cinturón Plegado del Cabo (en el sur de África), y en el Orógeno de Ross en Antartica. El evento metamórfico Pérmico es contemporáneo con la deformación y metamorfismo de bajo grado, registrado en las sucesiones sedimentarias que sobreyacen el basamento en muchas de estas areas. Siguiendo al episodio Pérmico de metamorfismo de alto grado, en Tierra del Fuego fueron removidos al menos 8 a 12 km de rocas de cobertura antes de la depositación de las rocas volcánicas de la Formación Tobífera en el Jurásico Medio y Superior. Las rocas erosionadas representan una fuente importante de material para las sucesiones conglomerádicas pérmicas y triásicas? ubicadas en las regiones vecinas de América del Sur, África y Antartica. Abstract in english Five new SHRTMP U-Pb zircon ages are reported for gneisses and foliated plutonic rocks belonging to the Tierra del Fuego igneous and metamorphic basement complex (TFIMC), obtained from the bottom of borehole cores through the Magallanes Basin. Three of the samples yielded weighted mean 206Pb/238U ages (523±7 Ma, 522±6 Ma and 538±6 Ma), interpreted as indicating Early Cambrian igneous crystallization of the host rocks. A migmatitic gneiss shows peaks at ca. 950-1,100 Ma (more) and 560-650 Ma from inherited zircon grains in addition to two grains with ages of ca. 525 Ma, suggesting involvement of Grenvillian and Brasiliano material in the protolith of a Cambrian migmatite. A cordierite-sillimanite-garnet gneiss contains igneous zircons of Cambrian age and a population of U-rich metamorphic Permian zircons, indicating that a Permian high-grade metamorphic and anatectic (P=2-3 kbar, T=730-770°C) event affected the Cambrian igneous rocks or sedimentary rocks derived from them. Cambrian/Ediacaran plutonic rocks are known from the basement of NW Argentina, the Sierra de la Ventana, the Cape Fold Belt in South Africa, and the Ross Orogen in Antarctica. The Permian metamorphic event is coeval with the deformation and low-grade metamorphism of the sedimentary successions that overlie the basement in many of these areas. In Tierra del Fuego at least 8 to 12 km of cover rocks were removed following the high-grade Permian metamorphic episode and the unconformable deposition of the Tobífera Formation volcanic rocks in the Middle to Late Jurassic. This eroded cover could nave been an important source of detritus for the conglomeratic Permian and Triassic? Successions of neighboring regions in South America, Africa and Antarctica.

Hervé, Francisco; Calderón, Mauricio; Fanning, C. Mark; Kraus, Stefan; Pankhurst, Robert J

2010-07-01

113

SHRIMP chronology of the Magallanes Basin basement, Tierra del Fuego: Cambrian plutonism and Permian high-grade metamorphism Geocronología SHRIMP del basamento de la Cuenca de Magallanes, Tierra del Fuego: plutonismo Cámbrico y metamorfismo Pérmico de alto grado  

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Full Text Available Five new SHRTMP U-Pb zircon ages are reported for gneisses and foliated plutonic rocks belonging to the Tierra del Fuego igneous and metamorphic basement complex (TFIMC), obtained from the bottom of borehole cores through the Magallanes Basin. Three of the samples yielded weighted mean 206Pb/238U ages (523±7 Ma, 522±6 Ma and 538±6 Ma), interpreted as indicating Early Cambrian igneous crystallization of the host rocks. A migmatitic gneiss shows peaks at ca. 950-1,100 Ma and 560-650 Ma from inherited zircon grains in addition to two grains with ages of ca. 525 Ma, suggesting involvement of Grenvillian and Brasiliano material in the protolith of a Cambrian migmatite. A cordierite-sillimanite-garnet gneiss contains igneous zircons of Cambrian age and a population of U-rich metamorphic Permian zircons, indicating that a Permian high-grade metamorphic and anatectic (P=2-3 kbar, T=730-770°C) event affected the Cambrian igneous rocks or sedimentary rocks derived from them. Cambrian/Ediacaran plutonic rocks are known from the basement of NW Argentina, the Sierra de la Ventana, the Cape Fold Belt in South Africa, and the Ross Orogen in Antarctica. The Permian metamorphic event is coeval with the deformation and low-grade metamorphism of the sedimentary successions that overlie the basement in many of these areas. In Tierra del Fuego at least 8 to 12 km of cover rocks were removed following the high-grade Permian metamorphic episode and the unconformable deposition of the Tobífera Formation volcanic rocks in the Middle to Late Jurassic. This eroded cover could nave been an important source of detritus for the conglomeratic Permian and Triassic? Successions of neighboring regions in South America, Africa and Antarctica.Cinco nuevas edades radiométricas logradas mediante análisis U-Pb en circón utilizando el SHRIMP, fueron determinadas en gneises y rocas plutónicas foliadas obtenidas desde el fondo de pozos de sondajes en la Cuenca de Magallanes y pertenecientes al denominado Complejo ígneo y Metamór-fico de Tierra del Fuego. En tres de las muestras fueron calculadas edades del Cámbrico Temprano (523±7 Ma, 522±6 Ma y 538±6 Ma), interpretadas como edades de cristalización ígnea de las rocas estudiadas. Un gneis migmatítico presenta 'peaks' de circones heredados de ca. 950-1.100 Ma y de 560-650 Ma además de dos granos de edades de 525 Ma, indicando la participación de material Grenviliano y Brasiliano en el protolito de la migmatita cámbrica. Un gneiss de cordierita-sillimanita-granate presenta una población de circones ígneos de edad cámbrica y otro grupo de circones metamórficos, ricos en U, de edad pérmica, indicando que en el Pérmico un evento metamórfico del alto grado acompañado de anatexis (P=2-3 kbar, T=730-770°C) afectó a rocas ígneas cámbricas y/o a rocas sedimentarias derivadas de ellas. Rocas plutónicas cámbricas/ediacaranas han sido descritas en el NW de Argentina, en los basamentos de la Sierra de la Ventana y del Cinturón Plegado del Cabo (en el sur de África), y en el Orógeno de Ross en Antartica. El evento metamórfico Pérmico es contemporáneo con la deformación y metamorfismo de bajo grado, registrado en las sucesiones sedimentarias que sobreyacen el basamento en muchas de estas areas. Siguiendo al episodio Pérmico de metamorfismo de alto grado, en Tierra del Fuego fueron removidos al menos 8 a 12 km de rocas de cobertura antes de la depositación de las rocas volcánicas de la Formación Tobífera en el Jurásico Medio y Superior. Las rocas erosionadas representan una fuente importante de material para las sucesiones conglomerádicas pérmicas y triásicas? ubicadas en las regiones vecinas de América del Sur, África y Antartica.

Francisco Hervé; Mauricio Calderón; C. Mark Fanning; Stefan Kraus; Robert J Pankhurst

2010-01-01

114

Influence of an intrusion on the extent of isomerism in acyclic isoprenoids in the Permian Kupferschiefer of the Lower Rhine Basin, N. W. Germany  

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The intrusive body near Krefeld, North-West Germany, the so-called Krefeld High, is known to have increased the coalification of the Carboniferous coal seams in the western part of the Ruhr coal mining district. However, no evidence of its influence on the partly overlying Permian sediments has been given to date. Therefore, organic geochemical investigations on the extractable organic matter from 30 core samples of the Permian Kupferschiefer covering an area of about 600km{sup 2} were undertaken. The determination of selected molecular maturation parameters reveals a low average maturation of the Kupferschiefer within the area investigated. Locally varying thermal effects could be measured by the extent of isomerism of pristane and phytane. In an area not affected by the intrusive body the extent of isomerism is shown to be influenced only by the burial depth and by some minor tectonic events. In the proximity of the Krefeld High, the extent of isomerism is significantly higher than expected from the actual burial depth. The extent of pristane and phytane epimerisation have been used to deduce isolines for the characterisation of thermal effects in the area investigated. 32 refs., 7 figs., 2 tabs.

Puettmann, W.; Eckhardt, C.B. (Lehrstuhl fuer Geologie, Geochemie und Lagerstaetten des Erdoels und der Kohle, Aachen (Germany, F.R.))

1989-01-01

115

Petrographic report on clay-rich samples from Permian Unit 4 salt, G. Friemel No. 1 well, Palo Duro Basin, Deaf Smith County, Texas: unanalyzed data  

Energy Technology Data Exchange (ETDEWEB)

This report presents the results of mineralogic and petrographic analyses performed on five samples of clay-rich rock from salt-bearing Permian strata sampled by drill core from G. Friemel No. 1 Well, Deaf Smith County, Texas. Five samples of clay-rich rock from depths of about 2457, 2458, 2521, 2548, and 2568 feet were analyzed to determine the amounts of soluble phase (halite) and the amounts and mineralogy of the insoluble phases. The amounts of halite found were 59, 79, 47, 40, and 4 weight percent, respectively, for the samples. The insoluble minerals are predominately clay (20 to 60 volume percent) and anhydrite (up to 17 volume percent), with minor (about 1.0%) and trace amounts of quartz, dolomite, muscovite, and gypsum. The clays include illite, chlorite, and interstratified chlorite-smectite. The results presented in this petrographic report are descriptive, uninterpreted data. 2 references, 7 tables.

Fukui, L.M.

1983-09-01

116

Petrographic report on clay-rich samples from Permian Unit 4 salt, G. Friemel No. 1 well, Palo Duro Basin, Deaf Smith County, Texas: unanalyzed data  

International Nuclear Information System (INIS)

This report presents the results of mineralogic and petrographic analyses performed on five samples of clay-rich rock from salt-bearing Permian strata sampled by drill core from G. Friemel No. 1 Well, Deaf Smith County, Texas. Five samples of clay-rich rock from depths of about 2457, 2458, 2521, 2548, and 2568 feet were analyzed to determine the amounts of soluble phase (halite) and the amounts and mineralogy of the insoluble phases. The amounts of halite found were 59, 79, 47, 40, and 4 weight percent, respectively, for the samples. The insoluble minerals are predominately clay (20 to 60 volume percent) and anhydrite (up to 17 volume percent), with minor (about 1.0%) and trace amounts of quartz, dolomite, muscovite, and gypsum. The clays include illite, chlorite, and interstratified chlorite-smectite. The results presented in this petrographic report are descriptive, uninterpreted data. 2 references, 7 tables

1983-01-01

117

News Palynology data of the basal section of Formacion San Gregorio located in Paso de las Bochas (I lower permian north basin, Uruguay  

International Nuclear Information System (INIS)

Samples from outcrops and concretions of the locality of Paso de las Bochas on the Negro River, provided new palynologycal data to the basal section of the San Gregorio Formation. At least 10 new ta xa are added for San Gregorio concretions, and some of the cited palynomorphs are mentioned for the first time for Uruguay (Rattiganispora minor, Waltzispora pol ita). Moreover, some of the found ta xa have been mentioned for glacial deposits related to the Carboniferous-Permian boundary in other Gondwana regions (p.e. Psomospora detect a, Waltzispora pol ita). The preliminary results reached here allow to admit the hypothesis of the existence of carboniferous dee posits on the Uruguayan territory whose were eroded or not yet recognized. Keywords: San Gregorio Formation, Carboniferous.

2004-01-01

118

Strike variability of carbonate platform margin stratal architecture and cycle stacking patterns: Outcrop and seismic examples from lower Permian depositional sequences of the Permian Basin, U.S.A.  

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Strike variability in stratal architecture, cycle stacking patterns and facies differentiation within sequences exemplifies the potential for differential stratigraphic response of platforms to eustasy. Variability exists within base-level cycles of several scales within a compound stratigraphic hierarchy, though the causes may vary among different scales. Cross-sections from outcrops in the Sierra Diablo document the framework and stacking pattern of 3rd-order sequences (HFS), including: two progradational middle Wolfcampian HFS (mW1-2), one backstepped upper Wolfcampian HFS (uW1), one progradational lower Leonardin HFS (L1), aggradational middle (L2) and upper Leonardian HFS (L3), three progradatic upper Leonardian HFS (L4-6), and two backstepped, aggradational upper Leonardian HFS (L7-8). Seismic lines from the northern Delaware and Midland Basins and San Simon Channel area document the regional consistency of 3rd-order sequence stacking patterns (a response to eustasy), but show variability related to local subsidence, antecedent topography (owing to deeper structures and platform margin erosion), windward vs. leeward facing, and siliciclastic sediment supply. Sequences L2 and L3 appear to exhibit the greatest variability in stacking pattern. Strike variability in 4th/5th-order cycle stacking patterns within 3rd-order sequences as studied in outcrop is greatest in sequences L2 and L3, in which headland-bight margin trends are developed on a lateral scale of 1-2 miles. Aggrational to backstepping reef-margin facies with steep ({le}35{degrees}) foreslopes developed along headlands. Mudstones abut these margin facies abruptly along headlands and may contain megabreccias at the toe-of-slope. More gently sloping (10-15{degrees}) {open_quotes}ramp{close_quotes} margin strata composed of fusulinid packstones characterize bights.

Fitchen, W.M. [Univ. of Texas, Austin, TX (United States)

1996-12-31

119

Taphonomy of Condensed Shell Storm beds of the Teresina Formation in Rio Preto (State of Paraná, Middle Permian, Paraná Basin): Paleoenvironmental Implications  

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Full Text Available The deposits of the Permian Teresina Formation are mainly characterized by fi ne-grained siliciclastic rocks and centimetricintercalations of tempestites (bioclastic sandstones and coquinas). Despite the relevance of the bivalve-rich carbonate bedsof the Teresina Formation to paleoenvironmental studies, their taphonomy is still poorly studied. The fossil concentrationstudied in this work was found in a quarry in the city of Irati, Rio Preto district, Paraná State. The fossil concentration is locatedin the middle/upper portion of the unit, far from the top. The studied bed is a bioclastic, intraclastic, peloidal, grainstone/packstone, with abundant bivalve shell fragments, pelitic and micritic intraclasts, peloids, rare ooids and oncoids, as well aspermineralized of Lycophyta microphylles and fi sh scales. The grains of this carbonate concentration show: high degree oftime-averaging, variable degree of packing (dense to disperse), no sorting and chaotic orientation. Notably, the concentrationincludes a mixture of elements which are indicative of: a) restrictive, low energy, carbonate environment (peloids, ooidsand oncoids); b) subaerial environment surrounding the main body of water (Lycophyta microphylles) and c) quiet-waterenvironment punctuated by storm events, where the suspension-feeding bivalves thrived. At least four depositional eventscaused by storm fl ows were recorded. The amalgamated nature of the bed is a result of storm events in an intracratonic basinwith very low seafl oor slope and low rates of sedimentation and subsidence.

Jacqueline Peixoto Neves; Rosemarie Rohn Davies; Marcello Guimarães Simões

2011-01-01

120

Contribution of research borehole data to modelling fine-grained turbidite reservoir analogues, Permian Tanqua-Karoo basin-floor fans (South Africa)  

Energy Technology Data Exchange (ETDEWEB)

Outcrop analogue studies can be augmented and constrained by drilling research wells through the same stratigraphic interval. Close-to-outcrop wells help to validate outcrop observations with well log and core data and thus improve the use of such data in actual field developments. Research wells located further away from the outcrops increase the spatial data coverage and can give important insight into regional facies distributions and net:gross changes. In the Tanqua-Karoo Basin (South Africa), seven wells were drilled into fine-grained sand-rich basin-floor fans and interfan mudstones to supplement outcrop data. Three close-to-outcrop wells proved useful in establishing characteristic log responses of the main architectural elements identified from the nearby outcrops. Lithofacies were correctly identified in more than 80% of cases using an artificial neural network. Borehole images provided detailed information on sedimentary structures, including a wealth of palaeocurrent data from climbing ripples that significantly enhanced the interpretations based only on outcrops. Wells sited away from the outcrops supplied information on lateral thickness and facies trends and intrafan stacking patterns, which helped to define the stratigraphic evolution of the fans. The combined data indicate that deposition was controlled in part by subtle basin-floor topography, and that intrafan lobe switching took place, leading to internal subdivisions that potentially caused effective compartmentalization of the basin-floor fan. (Author)

Luthi, Stefan M. [Delft Univ. of Technology, Dept. of Geotechnology, Delft (Netherlands); Hodgson, David M.; Flint, Stephen S. [Liverpool Univ., Dept. of Earth and Ocean Sciences, Liverpool (United Kingdom); Drinkwater, Nicholas J. [Schlumberger Cambridge Research, Cambridge (United Kingdom); Johannessen, Erik P. [Statoil, Stavanger (Norway); Geel, Cees R.; Goedbloed, Jan Willem

2006-07-01

 
 
 
 
121

Permian and uranium metallogeny  

International Nuclear Information System (INIS)

[en] In Europe, many uranium deposits are of Permian age and the following models are discussed: (1) Formation of uranium deposits during the Permian. Many granite-associated uranium deposits in France, Portugal and Czechoslovakia are dated at between 290 and 260 Ma. Stable isotopic data have shown that sedimentary formation waters and meteoric waters are important in the mineralisation process. (2) Uranium preconcentration during the Permian. Sedimentation is favourable to uranium concentration, especially in organic-rich environments. The presence of zirconium in pitchblende indicates leaching of cinerites during the mineralisation process. (3) Formation of uranium deposits in the Permian host rocks. Two major periods (170-185 Ma and 100-110 Ma) were identified that correspond to phases of extension related to oceanic openings. For the 180 Ma mineralisation, the role of sedimentary brines has been demonstrated. Some mineralisation of Alpine age are also known. (4) Spatial association of uranium deposits with Permian formations. The Mullenbach uranium deposit (FRG) located in Upper Carboniferous sediments beneath sediments of Permian age has been dated at 240 Ma. This corresponds to the tectonic phase between the Permian and the Triassic periods. Fluid circulation along a vertical redox front (oxidised Permian - reduced Carboniferous) is responsible for the deposition of pitchblende[fr] En Europe, de nombreux gisements d'uranium sont d'age permien et les modeles suivants sont discutes: (1) Formation de gisements d'uranium durant le Permien. De nombreux gisements d'uranium intragranitiques en France mais aussi au Portugal et en Tchecoslovaquie sont dates entre 290 et 260 Ma. Les donnees des isotopes stables ont montre que les eaux de formation des bassins sedimentaires et les eaux meteoriques ont joue un role important dans le processus mineralisateur. (2) Preconcentration d'uranium durant le Permien. La sedimentation est favorable a des preconcentrations d'uranium, en particulier dans les environnements riches en matieres organiques. La presence de zirconium dans la pechblende est interpretee comme l'indice du lessivage des cinerites durant le processus mineralisateur. (3) Formation de gisements d'uranium dans les formations sedimentaires permiennes. Deux periodes majeures sont reconnues (170-185 Ma et 100-110 Ma) qui correspondent a des phases d'extension liees a des ouvertures oceaniques. Pour les mineralisations jurassiques, le role des saumures sedimentaires a ete mis en evidence. Des mineralisations d'age alpin sont egalement connues. (4) Association spatiale de gisements d'uranium avec les formations permiennes. Le gisement d'uranium de Mullenbach (R.F.A.) localise dans des sediments carboniferes immediatement sous des sediments permiens a ete date a 240 Ma. Cet age correspond a la phase tectonique (palatine) entre le Permien et le Trias. La circulation verticale des solutions mineralisatrices le long d'un front redox (Permien oxyde et Carbonifere reduit) est responsable du depot de la pechblende

1990-01-01

122

Early Permian bipedal reptile.  

UK PubMed Central (United Kingdom)

A 290-million-year-old reptilian skeleton from the Lower Permian (Asselian) of Germany provides evidence of abilities for cursorial bipedal locomotion, employing a parasagittal digitigrade posture. The skeleton is of a small bolosaurid, Eudibamus cursoris, gen. et sp. nov. and confirms the widespread distribution of Bolosauridae across Laurasia during this early stage of amniote evolution. E. cursoris is the oldest known representative of Parareptilia, a major clade of reptiles.

Berman DS; Reisz RR; Scott D; Henrici AC; Sumida SS; Martens T

2000-11-01

123

Early Permian bipedal reptile.  

Science.gov (United States)

A 290-million-year-old reptilian skeleton from the Lower Permian (Asselian) of Germany provides evidence of abilities for cursorial bipedal locomotion, employing a parasagittal digitigrade posture. The skeleton is of a small bolosaurid, Eudibamus cursoris, gen. et sp. nov. and confirms the widespread distribution of Bolosauridae across Laurasia during this early stage of amniote evolution. E. cursoris is the oldest known representative of Parareptilia, a major clade of reptiles. PMID:11062126

Berman, D S; Reisz, R R; Scott, D; Henrici, A C; Sumida, S S; Martens, T

2000-11-01

124

Permian karst topography in the Wichita uplift, southwestern Oklahoma  

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The Wichita uplift in southwestern Oklahoma is one part of a record of Pennsylvania and early Permian deformation that affected the Southern Oklahoma aulacogen. As a result of a partial inversion, the Lower Paleozoic section of this aulacogen was sequentially stripped off an uplift between the Wichita uplift and the Anadarko basin, resulting in the exposure of ultrabasic rocks deep in the Cambrian igneous fill of the aulacogen. Following the late Paleozoic tectonism, the topography of the uplift was entombed beneath Permian sediments and remained essentially undisturbed until exhumation during the present erosional cycle. Modern erosion is gradually exposing this topography, permitting morphometric analysis of the Permian hill forms. Because of the variation of lithology in the uplift, it is possible to isolate the effects of weathering processes such as intense hydrolysis of the igneous rocks (producing, among other features, or topography) and limestone dissolution, in the form of a surface and subsurface karst imprint. The latter process resulted in a network of small caves that are essentially fissures eroded along tectonic fractures. These small caves can be found in all the exposed areas of limestone. They are particularly noteworthy for three reasons: in at least five examples they contain a complex fauna of Permian vertebrates (mostly fragmentary), speleothems in some examples contain hydrocarbon inclusions, derived from the underlying Anadarko basin, some of the caves yield evidence of post burial evolution in the form of clay infiltration from the surface and brine flushing from the underlying Anadarko basin.

Donovan, R.N. Busbey, A.B. (Texas Christian Univ., Ft. Worth, TX (United States). Geology Dept.)

1993-02-01

125

Middle-Late Permian mass extinction on land  

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The end-Permian mass extinction has been envisaged as the nadir of biodiversity decline due to increasing volcanic gas emissions over some 9 million years. We propose a different tempo and mechanism of extinction because we recognize two separate but geologically abrupt mass extinctions on land, one terminating the Middle Permian (Guadalupian) at 260.4 Ma and a later one ending the Permian Period at 251 Ma. Our evidence comes from new paleobotanical, paleopedological, and carbon isotopic studies of Portal Mountain, Antarctica, and comparable studies in the Karoo Basin, South Africa. Extinctions have long been apparent among marine invertebrates at both the end of the Guadalupian and end of the Permian, which were also times of warm-wet greenhouse climatic transients, marked soil erosion, transition from high- to low-sinuosity and braided streams, soil stagnation in wetlands, and profound negative carbon isotope anomalies. Both mass extinctions may have resulted from catastrophic methane outbursts to the atmosphere from coal intruded by feeder dikes to flood basalts, such as the end-Guadalupian Emeishan Basalt and end-Permian Siberian Traps.

Retallack, G.J.; Metzger, C.A.; Greaver, T.; Jahren, A.H.; Smith, R.M.H.; Sheldon, N.D. [University of Oregon, Eugene, OR (United States). Dept. of Geological Science

2006-11-15

126

A saponite and chlorite-rich clay assemblage in permian evaporite and red-bed strata, Palo Duro Basin, Texas Panhandle  

Energy Technology Data Exchange (ETDEWEB)

In this Department of Energy-funded project, the author describes lithology of core samples from two Department of Energy wells in Randall and Swisher Counties and determines clay mineralogy and X-ray diffraction response using 73 samples from the Randall County well and 40 samples from the Swisher County well. On the basis of his analyses, the author identifies the clay assemblage in the Palo Duro Basin evaporites as consisting of saponite, a magnesium-rich smectite; mixed-layer chlorite/smectite; chlorite/vermiculite; chlorite/swelling chlorite; vermiculite/swelling chlorite; chlorite, and illite. Chemical analyses reveal that the chemical composition of the mixed-layer clays is intermediate between normal aluminum-rich detrital clays and normal vermiculite and chlorite, magnesium clays of hydrothermal or metamorphic origin. The author postulates that rates and amounts of clay alteration are probably controlled by magnesium ion activity, brine salinity, brine pH, and sediment and clay residence time in the marine evaporite environment.

Palmer, D.P.

1987-01-01

127

Comparative petrological analysis between the Permian coals of India and Western Australia: paleoenvironments and thermal history  

Energy Technology Data Exchange (ETDEWEB)

Permian sequences preserved in Western Australian basins (Collie, Perth and Canning) and the Gondwana basins of India (Damodar, Son-Mahanadi, Pench-Kanhan and Godavari Valley) have similar stratigraphic succession, faunal and floral assemblages, coal types and rank, and structure. The type and rank of the Permian coals indicate a similar depositional and thermal histories for the basins studied in India and western Australia. This is consistent with the view that India and Western Australia were in close proximity before the break up of Gondwanaland.

Mishra, H.K. [Central Mine Planning and Design Institute Ltd., Ranchi (India). Division of Exploration

1996-10-01

128

Permian potentiometric analysis  

Energy Technology Data Exchange (ETDEWEB)

Pacific Northwest Laboratory (PNL) was requested to analyze potentiometric data from the Wolfcamp Formation of the Permian System to evaluate the recommendations by the University of Texas/Bureau of Economic Geology (UT/BEG) that additional geohydrologic boreholes be drilled into the Wolfcamp. The UT/BEG recommended that two stratigraphic and two geohydrologic borings be drilled into the Permian System during FY83 and that several shallow hydrologic tests be made in the Dockum Formation. A geostatistical technique known as kriging was applied to objectively evaluate these geohydrologic borehole recommendations. The Deaf Smith County location appears to be an excellent choice for a borehole. No high quality potentiometric data are available from Deaf Smith County and a borehole location immediately upgradient from the candidate repository site is needed. Adding this borehole location to the potentiometric data base will significantly reduce field data uncertainty near the location being studied. The Swisher County location does not appear to be the best choice. High quality data values H2206 and H2360 are located immediately upgradient from the proposed repository site. The best placement of additional geohydrological boreholes in the Wolfcamp Formation depends strongly upon the proposed repository location. The variability of the potentiometric data causes estimation errors to rapidly increase away from locations of field measurements. Suggested locations for additional boreholes for the Deaf Smith investigations are in northwest Randall or central Potter Counties. Ideal borehole locations for the Swisher county studies appear to be in southeast Randall and Armstrong Counties.

Devary, J.L.

1983-09-01

129

Permian potentiometric analysis  

International Nuclear Information System (INIS)

Pacific Northwest Laboratory (PNL) was requested to analyze potentiometric data from the Wolfcamp Formation of the Permian System to evaluate the recommendations by the University of Texas/Bureau of Economic Geology (UT/BEG) that additional geohydrologic boreholes be drilled into the Wolfcamp. The UT/BEG recommended that two stratigraphic and two geohydrologic borings be drilled into the Permian System during FY83 and that several shallow hydrologic tests be made in the Dockum Formation. A geostatistical technique known as kriging was applied to objectively evaluate these geohydrologic borehole recommendations. The Deaf Smith County location appears to be an excellent choice for a borehole. No high quality potentiometric data are available from Deaf Smith County and a borehole location immediately upgradient from the candidate repository site is needed. Adding this borehole location to the potentiometric data base will significantly reduce field data uncertainty near the location being studied. The Swisher County location does not appear to be the best choice. High quality data values H2206 and H2360 are located immediately upgradient from the proposed repository site. The best placement of additional geohydrological boreholes in the Wolfcamp Formation depends strongly upon the proposed repository location. The variability of the potentiometric data causes estimation errors to rapidly increase away from locations of field measurements. Suggested locations for additional boreholes for the Deaf Smith investigations are in northwest Randall or central Potter Counties. Ideal borehole locations for the Swisher county studies appear to be in southeast Randall and Armstrong Counties

1983-01-01

130

Siberian gas venting and the end-Permian environmental crisis  

Science.gov (United States)

The end of the Permian period is marked by global warming and the biggest known mass extinction on Earth. The crisis is commonly attributed to the formation of the Siberian Traps Large Igneous Province although the causal mechanisms remain disputed. We show that heating of Tunguska Basin sediments by the ascending magma played a key role in triggering the crisis. Our conclusions are based on extensive field work in Siberia in 2004 and 2006. Heating of organic-rich shale and petroleum bearing evaporites around sill intrusions led to greenhouse gas and halocarbon generation in sufficient volumes to cause global warming and atmospheric ozone depletion. Basin scale gas production potential estimates show that metamorphism of organic matter and petroleum could have generated > 100,000 Gt CO2. The gases were released to the end-Permian atmosphere partly through spectacular pipe structures with kilometre-sized craters. Dating of a sill intrusion by the U Pb method shows that the gas release occurred at 252.0 ± 0.4 million years ago, overlapping in time with the end-Permian global warming and mass extinction. Heating experiments to 275 °C on petroleum-bearing rock salt from Siberia suggests that methyl chloride and methyl bromide were significant components of the erupted gases. The results indicate that global warming and ozone depletion were the two main drivers for the end-Permian environmental crisis. We demonstrate that the composition of the heated sedimentary rocks below the flood basalts is the most important factor in controlling whether a Large Igneous Provinces causes an environmental crisis or not. We propose that a similar mechanism could have been responsible for the Triassic-Jurassic (~ 200 Ma) global warming and mass extinction, based on the presence of thick sill intrusions in the evaporite deposits of the Amazon Basin in Brazil.

Svensen, Henrik; Planke, Sverre; Polozov, Alexander G.; Schmidbauer, Norbert; Corfu, Fernando; Podladchikov, Yuri Y.; Jamtveit, Bjørn

2009-01-01

131

European Sedimentary Basins: Deciphering Palaeozoic intra-Pangea Wrench Faulting  

Science.gov (United States)

Thick sections of sedimentary deposits act as tape recorders of the geomagnetic field over time and allow high resolution paleogeographic reconstructions. Over the past years, we were able to put together a considerable paleomagnetic data set collected from Early Permian and Mesozoic deposits in numerous sedimentary basins throughout Southwest Europe. This data set monitors relative block rotations about vertical axis in this area and thus provides convincing evidence for intra-Pangean wrench faulting in the Early Permian (~ 285-265 Ma). Here, we present previously processed data from Permian sedimentary sections from Southwest France and Sardinia together with data from the Saar-Nahe basin in West Germany. New data from the Permian/Triassic boundary from Sardinian sedimentary basins and data from Permian dyke swarms add further information to draw a more complete picture of the paleogeographic evolution of the Gondwana/Laurasia plate boundary and help to describe controversial intra-Pangean mobility and wrench faulting in the Early Permian.

Aubele, K.; Bachtadse, V.; Muttoni, G.; Ronchi, A.; Durand, M.

2012-04-01

132

Paleomagnetic studies of Carboniferous and Permian in the U. K. Southern North Sea: Core orientation, paleocurrent analysis, and diagenetic application  

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The U.K. southern North Sea is a major gas province with production from Carboniferous and Permian reservoirs. It was a foreland basin in Carboniferous times uplifted to form a Lower Permian desert basin and subsequently deeply buried during the Mesozoic. Paleomagnetic methods have been used for burial analysis, core orientation, and paleocurrent studies. VRM is shown to be of only limited value for core orientation; problems relating to drilling effects and deflection by ChRM will be discussed. Detailed thermal demagnetization studies are most valuable. Blocking temperature spectra can be related to burial history curves, and ChRM directions isolated and compared with Carboniferous and Permian reference directions. ChRM is a valuable parameter for core orientation and thus paleocurrent studies. Examples will be shown from the Carboniferous and Lower Permian.

Turner, P. (Birmingham Univ. (United Kingdom)); Hartley, A.J. (Univ. College of Wales, Cardiff (United Kingdom))

1991-03-01

133

Geoscience/engineering characterization of the interwell environment in carbonate reservoirs based on outcrop analogs, Permian Basin, West Texas and New Mexico-stratigraphic hierarchy and cycle stacking facies distribution, and interwell-scale heterogeneity: Grayburg Formation, New Mexico. Final report  

Energy Technology Data Exchange (ETDEWEB)

The Grayburg Formation (middle Guadalupian) is a major producing interval in the Permian Basin and has yielded more than 2.5 billion barrels of oil in West Texas. Grayburg reservoirs have produced, on average, less than 30 percent of their original oil in place and are undergoing secondary and tertiary recovery. Efficient design of such enhanced recovery programs dictates improved geological models to better understand and predict reservoir heterogeneity imposed by depositional and diagenetic controls. The Grayburg records mixed carbonate-siliciclastic sedimentation on shallow-water platforms that rimmed the Delaware and Midland Basins. Grayburg outcrops in the Guadalupe and Brokeoff Mountains region on the northwest margin of the Delaware Basin present an opportunity to construct a detailed, three-dimensional image of the stratigraphic and facies architecture. This model can be applied towards improved description and characterization of heterogeneity in analogous Grayburg reservoirs. Four orders of stratigraphic hierarchy are recognized in the Grayburg Formation. The Grayburg represents a long-term composite sequence composed of four high-frequency sequences (HFS 1-4). Each HFS contains several composite cycles comprising two or more cycles that define intermediate-scale transgressive-regressive successions. Cycles are the smallest scale upward-shoaling vertical facies successions that can be recognized and correlated across various facies tracts. Cycles thus form the basis for establishing the detailed chronostratigraphic correlations needed to delineate facies heterogeneity.

Barnaby, R.J.; Ward, W.B.; Jennings, J.W. Jr.

1997-06-01

134

Permian-Triassic mafites of Sette-Daban  

International Nuclear Information System (INIS)

The paper describe the ores which form the Permian-Triassic dike zones of the Southern part of the Sette-Daban fold-blowing structure adjacent to the Siberian platform. The data are presented on K-Ar age of gabbro-diabase dike in the basin of Ariavkan River: the age of plagioclase is 276 ± 1 million years and that of kali feldspar - 222 ± 30 million years. It agrees with potassium - argon dating of mafites with similar compositions in the Northern part of the region. It is shown that the Permian-Triassic dikes can be of interest for the prospecting of the deposits of lead, zinc, phosphates and other minerals. 10 refs., 1 fig., 1 tab,.

1995-01-01

135

Early Permian Pangea `B' to Late Permian Pangea `A'  

Science.gov (United States)

The pre-drift Wegenerian model of Pangea is almost universally accepted, but debate exists on its pre-Jurassic configuration since Ted Irving introduced Pangea 'B' by placing Gondwana farther to the east by ˜3000 km with respect to Laurasia on the basis of paleomagnetic data. New paleomagnetic data from radiometrically dated Early Permian volcanic rocks from parts of Adria that are tectonically coherent with Africa (Gondwana), integrated with published coeval data from Gondwana and Laurasia, again only from igneous rocks, fully support a Pangea 'B' configuration in the Early Permian. The use of paleomagnetic data strictly from igneous rocks excludes artifacts from sedimentary inclination error as a contributing explanation for Pangea 'B'. The ultimate option to reject Pangea 'B' is to abandon the geocentric axial dipole hypothesis by introducing a significant non-dipole (zonal octupole) component in the Late Paleozoic time-averaged geomagnetic field. We demonstrate, however, by using a dataset consisting entirely of paleomagnetic directions with low inclinations from sampling sites confined to one hemisphere from Gondwana as well as Laurasia that the effects of a zonal octupole field contribution would not explain away the paleomagnetic evidence for Pangea 'B' in the Early Permian. We therefore regard the paleomagnetic evidence for an Early Permian Pangea 'B' as robust. The transformation from Pangea 'B' to Pangea 'A' took place during the Permian because Late Permian paleomagnetic data allow a Pangea 'A' configuration. We therefore review geological evidence from the literature in support of an intra-Pangea dextral megashear system. The transformation occurred after the cooling of the Variscan mega-suture and lasted ˜20 Myr. In this interval, the Neotethys Ocean opened between India/Arabia and the Cimmerian microcontinents in the east, while widespread lithospheric wrenching and magmatism took place in the west around the Adriatic promontory. The general distribution of plate boundaries and resulting driving forces are qualitatively consistent with a right-lateral shear couple between Gondwana and Laurasia during the Permian. Transcurrent plate boundaries associated with the Pangea transformation reactivated Variscan shear zones and were subsequently exploited by the opening of western Neotethyan seaways in the Jurassic.

Muttoni, Giovanni; Kent, Dennis V.; Garzanti, Eduardo; Brack, Peter; Abrahamsen, Niels; Gaetani, Maurizio

2003-10-01

136

Palynology of Permian Gondwana sequence of Umrer coalfield, Maharashtra  

Energy Technology Data Exchange (ETDEWEB)

Quantitative and qualitative palynological analysis of Early Permian sediments, Umrer Coalfield, Wardha Basin has been carried out. The microspore assemblage consists of 22 genera and 40 species. It is characterized by dominance of radial monosaccates chiefly, Parasacciles and subdominance of non-striate disaccates chiefly, Scheuringipollenites. Presence of Crucisaccites and Caheniasaccites suggests Upper Karharbari (Late Sakmarian-Early Artinskian) affinity. The presence of the Karharbari palynozone has been demarcated in lithologically designated Barakar Formation. The present finding corroborates the earlier studies by Bharadwaj and Anand Prakash (1974).

Jha, N.; Tewari, R.; Rajanikanth, A. [Birbal Sahni Institute of Paleobotany, Lucknow (India)

2007-04-15

137

Unayzah Formation: a new Permian-Carboniferous unit in Saudi Arabia  

Energy Technology Data Exchange (ETDEWEB)

The sandstones, shales, and thin beds of argillaceous limestone previously included as the basal part of the Permian Khuff Formation were described as the Unayzah Formation by al-Laboun in 1982 and 1986. The type locality (stratotype.) of this formation is in the town of Unayzah, and a reference section was established in the Qusayba area, al-Qasim district, Saudi Arabia. Fossil flora collected from outcrops and palynomorphs obtained from boreholes support a Late Carboniferous-Early Permian age for these strata. The Unayzah Formation is conformably overlain by the massive carbonates of the Khuff Formation, whereas its basal contact is marked by a regional angular unconformity with various older units. The Unayzah Formation is widespread in the Greater Arabian basin. The formation represents cyclic transgressive and regressive deposits preceding the Permian regional marine transgression, during which the massive carbonates of the Khuff Formation were deposited. This Permian transgression marked a major change in the Sedimentation and evolution of the Greater Arabian basin. The porous sandstones of the Unayzah Formation are important exploration targets because several fields in the eastern and southeastern parts of the Greater Arabian basin produce hydrocarbons from the Unayzah. 11 figures, 1 table.

Al-Laboun, A.A.

1987-01-01

138

Carboniferous and Permian stratigraphy in Guizhou  

Energy Technology Data Exchange (ETDEWEB)

A guide book prepared for Excursion 5 to southern Guizhou during the 11 International Congress of Carboniferous Stratigraphy and Geology. The excursion was aimed at examining some type sections of Carboniferous and Lower Permian, including the Devonian-Carboniferous boundary and the Carboniferous-Permian boundary. Mineral deposits of great economic significance are bauxite, manganese and coal.

Wei Jiayong; Xiao Weimin; Wang Hongdi; Dong Wenlan; Feng Rulin; Wu Xianghe; Zheng Shufang

1987-01-01

139

Early Permian intrusions in the Paleozoic sediments of the Eastern North Sea area  

DEFF Research Database (Denmark)

This study presents the geometry of Paleozoic intrusions in the Skagerrak area located at the northern flank of the Ringkøbing-Fyn High and suggests factors controlling the formation of the intrusions. The intrusions have here been mapped in detail using 3D seismic data. The study area is located in the Northern Permian Basin which in the eastern North Sea is separated from the Southern Permian Basin by the Ringkøbing-Fyn High. The Permian basins were initiated during thermal subsidence following a late Carboniferous- early Permian rifting phase associated with extensive igneous activity recorded across the entire North Sea Basin. The easternmost intrusions and extrusions have been associated to the “Skagerrak-Centered Large Igneous Province” that has an early Permian age of c. 297 Ma. Compared to the Southern Permian Basin which historically has been intensely investigated because of the known presence of hydrocarbons within the Paleozoic sediments, the Northern Permian Basin has gained much less interest outside the hydrocarbon producing Mesozoic graben systems. This is mainly due to an apparent lack of potential source rocks. A major E-W striking northward dipping fault system characterizes the study area and causes rotation of older probably Paleozoic sediments and creates syn-tectonic sediment wedges. The syn-tectonic wedges most probably contain volcaniclastic sediments of the Karl Formation or sandstones of the Auk Formation, but it cannot be excluded that the earliest late Permian Kupfershiefer which is a potential source rock, has local depositional maxima associated to the basement faults. Salt structures which have been periodically active during the post Paleozoic dominate the northern part of the study area. The Paleozoic intrusions observed in the hanging-wall segment of the E-W striking fault system are generally planar and strike parallel to the fault with a southward dip geometrically similar to antithetic faults. In contrast, the intrusions in the footwall segment show a much more complex pattern striking at a high angle to the E-W basement fault and outlining a sill complex, which in certain areas resembles a poorly outlined composite cone. The intrusions are not observed in the syn-tectonic sedimentary wedges and this combined with the general age of the intrusions suggests that the syn-tectonic wedges are of latest early Permian or earliest late Permian age. The study demonstrates Paleozoic intrusions with a systematic orientation and geometry that most likely was directly controlled by the basement faulting. Syn-tectonic hanging-wall deformation represented by antithetic fractures is suggested to be the most important controlling factor for the intrusions at the hanging-wall. At the footwall a more composite geometry of the intrusions is observed, resulting in a much more complex compartmentalization of the Paleozoic sediments due to intrusions compared to the hanging-wall segment. The intrusions and especially the compartmentalization must be taken into account during evaluation of the hydrocarbon potential of the Paleozoic.

Clausen, O.R.; Andresen, Katrine Juul

140

Permian of Southeast Asia: an overview  

Energy Technology Data Exchange (ETDEWEB)

Permian rocks are widely distributed throughout Southeast Asia. Because of the tropical-equatorial climate the rocks are commonly deeply weathered and covered by dense vegetation over much of the region. Elsewhere, Permian rocks are well exposed and easy to access, particularly where limestone outcrops have weathered to form spectacular, castellated, tower karst. Many limestone outcrops, containing abundant fusulinaceans, were recognized early on to be of Permian age, but many outcrops without fusulinaceans, erroneously assigned to the Permian, were found subsequently to be of Triassic age, and more careful studies have established the Permian age of rocks of other lithologies. Different depositional environments are represented by the Permian deposits in various parts of the region. Massive limestones, throughout the region represent extensive carbonate platforms; local occurrences of thick bedded cherts indicate deposition in deep marine environments, coal, bauxite and clastic sediments with vertebrate remains in North Vietnam and Laos indicate deposition in a continental environment, and pebbly mudstones in Myanmar, Peninsular Thailand, northwest Malaysia and Sumatra, are considered to have been formed in a glacial environment. Volcanic rocks are not found in northwest Peninsular Malaysia and Peninsular Thailand, but are extensively developed in North Vietnam, Sumatra, the eastern Malay Peninsula and Timor. Fossils are often prolific in Permian sediments, with fusulinaceans, for example, occurring in large numbers in many limestone outcrops. Age-diagnostic fossils demonstrate that the whole of the Permian is represented in different areas of Southeast Asia. Fossil faunal and floral assemblages have been used to establish climatic conditions and environments of deposition, to define distinct crustal blocks and to provide the basis for reconstructing the palaeogeography during Permian times.

Fontaine, H.

2002-07-01

 
 
 
 
141

Bivalves and brachiopods in the Carboniferous - Early Permian of Argentine Precordillera: Diversification and faunal turnover in Southwestern Gondwana  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Diversification patterns and faunistic turnovers of bivalves and brachiopods through the Carboniferous – Early Permian interval in the central western Argentinian basins are analyzed and compared with the global events proposed in former studies. This study reveals a generalized increase of bivalves...

Fabiana Sterren, Andrea

142

Permian basalts and trachytes from Esterel (SE France): a transitional tholeiitic suite emplaced during lithosphere thinning  

International Nuclear Information System (INIS)

Geochemical (major, trace and rare earth elements) and isotopic (143Nd/144Nd) compositions of lavas emplaced in the Esterel Massif (eastern Provence, France) at the end of the Permian allow to estimate the evolution of the continental lithosphere between the end of the Hercynian orogenesis and the beginning of the Tethyan rifting. Basalts from Agay basin and trachyte from Batterie des Lions belong to a transitional tholeiitic suite, characterized by negative Nb and Ta anomalies (relative to N-MORB) and homogeneous ?Nd(T=250Ma) ratios, close to the Bulk Earth. This suggests that the basalts from Agay basin and trachyte from Batterie des Lions derived from the partial melting of a mantle contaminated by lower continental crust. Maure Vieille trachytes differ from the differentiated rocks of the transitional suite by higher heavy rare earth abundances and ?Nd(T=250Ma) of +4/+5. These high ?Nd ratios suggest that the Maure Vieille trachytes could derive from the partial melting of a more depleted source, likely an asthenospheric mantle. The isotopic compositions of the Permian lavas from Esterel suggest the thinning (and perhaps the disappearance) of the lithospheric mantle which is associated at the surface with a NNW-SSE extension. The progressive change recorded in Agay basin from a stretching regime to a strike-slip regime may be related to the end of the lithospheric thinning and of the Permian magmatism. (authors)

1999-01-01

143

A potential biomarker for the Permian Triassic ecological crisis  

Science.gov (United States)

A unique biomarker, a C 33n-alkylcyclohexane ( n-heptacosylcyclohexane), which strongly increases in abundance within the extinction interval of the end-Permian ecological crisis, is here reported from the key Permian-Triassic (P-Tr) marine section in Greenland. Prior to this study, this compound had been known from Early Triassic organic-rich marine rocks and oils from the northern Perth Basin, Western Australia for two decades. We have identified the compound in high relative abundance in 29 samples from P-Tr marine sections from two separate paleogeographic localities, from Laurasia and Gondwana. Relative concentrations of the C 33n-alkylcyclohexane show similar changes to the relative abundances of extinct spinose acritarchs ( Veryhachium and Micrhystridium) indicating that the source organism of the C 33n-alkylcyclohexane is associated with the depositional environments/facies in which the acritarchs are identified. These organisms probably formed the cornerstone of the unique marine ecosystem that thrived in the extinction aftermath in the Early Triassic Ocean.

Grice, Kliti; Twitchett, Richard J.; Alexander, Robert; Foster, C. B.; Looy, Cindy

2005-07-01

144

Palinologia das formações Rio Bonito e Palermo (Permiano Inferior, Bacia do Paraná) em Candiota, Rio Grande do Sul, Brasil: novos dados e implicações bioestratigráficas/ Palynology of the Rio Bonito and Palermo formations (Lower Permian, Paraná Basin) in Candiota, Rio Grande do Sul, Brazil: new data and biostratigraphic implications  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Novos conjuntos palinológicos foram recuperados de um afloramento localizado às margens da BR 293, situado entre os municípios de Bagé e Candiota, sul do Estado do Rio Grande do Sul, correspondentes às formações Rio Bonito e Palermo, Permiano Inferior da Bacia do Paraná. Um total de oito amostras foi estudado, revelando palinofloras ricas e diversificadas, com a identificação de 76 espécies, dentre as quais 42 são relativas a esporos, 24 a grãos de pólen, e (more) 10 relacionadas a algas e fungos. Em termos bioestratigráficos, palinomorfos documentados na seqüência sedimentar analisada permitiram identificar duas unidades bioestratigráficas na seção, as zonas Vittatina costabilis e Lueckisporites virrkiae. Algumas espécies de distribuição estratigráfica limitada a determinados níveis do Subgrupo Itararé e da Formação Rio Bonito foram registrados em posição estratigráfica mais superior, podendo sugerir, à primeira vista, aumento na amplitude estratigráfica destes táxons. Entretanto, outras implicações estratigráficas são também admitidas, e constituem parte da discussão da presente contribuição. Abstract in english New palynologic associations were recovered from an outcrop located at BR 293 Highway, between Bagé and Candiota municipalities, Rio Grande do Sul state, Brazil, related to the Rio Bonito and Palermo formations, Lower Permian of Paraná Basin. Eight samples were colected and studied, showing rich and diversified palynofloras. A total of 76 species were recognized, 42 corresponding to spores, 24 to pollen grains and 10 related to algae and fungi. Palynomorphs registered i (more) n the section here analysed indicate the recognition of the Vittatina costabilis and Lueckisporites virrkiae zones. Species with stratigraphic ranges limitated to Itararé Subgroup and Rio Bonito Formation were identified in a higher stratigrapical levels, meaning for instance, increasing on the stratigraphic range of these taxa. On the other hand, other stratigraphic interpretations are possible, constituting the scope of the present contribution.

Mori, Ana L.O.; Souza, Paulo A.

2010-03-01

145

Provincialization of terrestrial faunas following the end-Permian mass extinction.  

UK PubMed Central (United Kingdom)

In addition to their devastating effects on global biodiversity, mass extinctions have had a long-term influence on the history of life by eliminating dominant lineages that suppressed ecological change. Here, we test whether the end-Permian mass extinction (252.3 Ma) affected the distribution of tetrapod faunas within the southern hemisphere and apply quantitative methods to analyze four components of biogeographic structure: connectedness, clustering, range size, and endemism. For all four components, we detected increased provincialism between our Permian and Triassic datasets. In southern Pangea, a more homogeneous and broadly distributed fauna in the Late Permian (Wuchiapingian, ?257 Ma) was replaced by a provincial and biogeographically fragmented fauna by Middle Triassic times (Anisian, ?242 Ma). Importantly in the Triassic, lower latitude basins in Tanzania and Zambia included dinosaur predecessors and other archosaurs unknown elsewhere. The recognition of heterogeneous tetrapod communities in the Triassic implies that the end-Permian mass extinction afforded ecologically marginalized lineages the ecospace to diversify, and that biotic controls (i.e., evolutionary incumbency) were fundamentally reset. Archosaurs, which began diversifying in the Early Triassic, were likely beneficiaries of this ecological release and remained dominant for much of the later Mesozoic.

Sidor CA; Vilhena DA; Angielczyk KD; Huttenlocker AK; Nesbitt SJ; Peecook BR; Steyer JS; Smith RM; Tsuji LA

2013-05-01

146

Radionuclides distribution in blooming of the permian sediments from the Irati Formation of the Parana Basin; Distribuicao de radionuclideos em um afloramento de sedimentos permianos da Formacao Irati na Bacia do Parana  

Energy Technology Data Exchange (ETDEWEB)

The objective of this work is to study natural radionuclides in sedimentary rocks. The concentration of them reflects the origin of the sediments, the depositional environment as well as some mineralogical characteristics of the rock matrix, and also more recent events as weathering and erosion. Using gamma ray high resolution spectrometry, the profile of activity concentration of the natural radionuclides was assessed for {sup 226}Ra, {sup 238}U, {sup 32}Th and {sup 40}K in rocks of the Irati Formation belonging to Parana Sedimentary Basin. The samples were collected at a limestone abandoned mine, in the city of Sapopema, (PR). 24 samples were collected, eleven from the exposed vertical profile with approximately 5.50 m, whose stratigraphy is represented by an alternation among decimetrics layers of limestones, bituminous shales, and some rhythmits layers (milimetric sheets of limestone and bituminous shales), 9 repetitions of a sample to study the variability, and three rigolits samples in sequential apprenticeships of weathering. Each sample was dried in the sun during about 48 hours, broken, drizzled in a sieve of 4 mesh and put, in a cylindrical container. The measures were accomplished using a Germanium Hyper Pure detector (HPGe) with relative efficiency of 66%, connected to a standard spectrometry electronic chain. The measured concentrations of activity of {sup 238}U were smaller for the limestones (17.80 {+-}0.09 Bq.Kg{sup -1}), larger for the bituminous shales (125.5 {+-} 2.6 Bq.Kg{sup -1} with enrichment of uranium in the sample (200), 548 {+-} 16 Bq.Kg{sup -1}, upper part of the column), and intermediate for the rhythmits (23.0 {+-} 1,3 Bq.Kg{sup -1}. The ratio eTh/K obtained for the studied profiles has equivalent values, indicating similar mineralogical characteristics for the limestones, bituminous shales, rhythmits and studied rigolits. On the other hand, to the ratio eTh/eU showed that two of the three regolits samples belong to oxidizer atmospheres, favoring the leaching of uranium, what can be causing the enrichment of the sample (200), once these soils are above the column. The average measured doses were 16 nGy.h{sup -1} for the limestones and rhythmits, 79.5 nGy.h{sup -1} for the bituminous shales and 329.5 nGy.h{sup -1} for the enriched bituminous shales of the top of the column. These results supply data to estimate the contribution of these products for the radiation dose received by the public in general, besides of database for mineralogical and geophysical studies of the Parana Basin. (author)

Ferreira, Ademar de Oliveira

2008-02-15

147

Early Permian deep-water allochthonous limestone facies and reservoir, west Texas  

Energy Technology Data Exchange (ETDEWEB)

Conventional cores from six wells in southwest Reagan and northern Crockett Counties, Texas, recovered interbedded limestone conglomerate, intraclast and bioclast limestone, calcarenite, and shale. Twenty-one lithologies are grouped into six lithofacies based on study of slabbed core surfaces. The limestone facies are interpreted on the basis of petrologic characteristics, biota regional stratigraphic setting, and facies stratigraphy as deep water and allochthonous. Biotic constituents within the lithoclasts and matrix indicate an Early Permian (Wolfcamp) age. Age and facies determinations from cores in the Gunnx area significantly alter earlier stratigraphic interpretations made with wireline logs alone. Late Paleozoic allochthonous carbonate facies may provide significant new reserves in the Permian basin. 19 figures, 2 tables.

Hobson, J.P.; Caldwell, C.D.; Toomey, D.F.

1985-12-01

148

Pangean Reconstruction of the Yucatan Block and its Permian, Triassic, and Jurassic Geologic and Tectonic History  

Science.gov (United States)

Paleomagnetic studies of Paleozoic sedimentary and plutonic rocks demonstrate that the Yucatan Block lay inverted off the NW coast of South America (SA) in Pangea, and rotated in a series of clockwise motions as SA and NA separated. Mid-Permian Yucatan was a fragment of the western margin of Pangea, just south of the equator. By 230 Ma, Yucatan rotated ˜20° clockwise and moved to the equator. Clockwise rotation continued through the Jurassic: ˜54° between 230 Ma and about Oxfordian, and another ˜32° between ˜Oxfordian and Tithonian, when the approximate present orientation was achieved. Passage of the Yucatan Block into the gap created by the separation of North and South America requires left-lateral motion relative to North America, perhaps by translation along the Mojave Sonora megashear. One remanence, carried by magnetite in red bed strata from the margins of the marine Santa Rosa basin (Maya Mtns), decays exceedingly linearly to the origin of orthogonal-axes plots. Biostratigraphy indicates a Late Pennsylvanian to Middle Permian age, and the presence of dual polarities in a 110 m, four polarity, magnetostratigraphic sequence demonstrates a post-Late Paleozoic Reversed Superchron (i.e., Middle Permian) age. Plutonic rocks exhibit a second, also dual-polarity, remanence, which corresponds to a paleopole 60° clockwise of the mid-Permian pole. The spatial relationship between the Permian and pluton paleopoles is very similar to that of the North American Permian and Late Triassic poles. Moreover, exceedingly uniform K/Ar ages of 231±7 Ma characterize all Maya Mtns plutons and the southern volcanic complex, indicating a 230 Ma resetting of the K/Ar radiometric systems of plutons dated by U/Pb as Late Silurian (Steiner and Walker, 1996). Metamorphic aureoles developed in the Pennsylvanian-Permian Santa Rosa strata bordering the Silurian plutonic complexes suggest the occurrence of a post-intrusion hydrothermal event. The 230 Ma reset K/Ar systems, metamorphic aureoles in strata younger than the plutons, and a magnetization resembling a Late Triassic remanence all suggest that a 230 Ma hydrothermal event remagnetized and reset the igneous rocks, probably during the initial break-up of Pangea. The Maya Mtns pluton paleopole is statistically identical to that of the Chiapas Massif. Identical dual polarity magnetization populations characterizing both of these Yucatan plutonic complexes suggest that both were remagnetized around 230 Ma. Importantly, identical remanences in these widely separated plutonic complexes indicate that the Yucatan Block (including the Chiapas Massif) has been a structural entity since at least 230 Ma.

Steiner, M.

2004-12-01

149

Permian plants from the Chutani Formation (Titicaca Group, Northern Altiplano of Bolivia): II. The morphogenus Glossopteris  

Directory of Open Access Journals (Sweden)

Full Text Available Fossil plants belonging to the morphogenera Glossopteris, Pecopteris and Asterotheca were collected from the upper part of the Chutani Formation (Titicaca Group), near the town of San Pablo de Tiquina, on the southeastern shore of Lake Titicaca (northern Altiplano, Bolivia). This paper presents the first description of specimens of the morphogenus Glossopteris from Bolivia. The Bolivian specimens of Glossopteris consist of poorly-preserved impressions, although they present the diagnostic features of this morphogenus. They are fragments of leaves with secondary veins of taeniopterid-type, typical of glossopterids from Late Permian deposits of Gondwana. The only species of Pecopteris confirmed in the first part of this study, i.e. P. dolianitii Rösler and Rohn (see Vieira et al. 2004), was previously reported from the Late Permian beds of the Rio do Rasto and Estrada Nova formations in the Paraná Basin (southern Brazil). Therefore, a Late Permian age is proposed for the fossil plant-bearing beds of the Chutani Formation based on the analyzed assemblage. The phytogeographic implications of this new find are briefly analyzed.

Iannuzzi Roberto; Vieira Carlos E. L.; Guerra-Sommer Margot; Díaz-Martínez Enrique; Grader George W.

2004-01-01

150

Megaspores from coals of the Triunfo Member, Rio Bonito Formation (Lower Permian), northeastern Paraná State, Brazil  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents the results of a detailed study of megaspores occurring in coal seams of the Triunfo Member, Rio Bonito Formation at Figueira, Paraná State, Brazil. This coal-bearing sequence accumulated in a marine delta system during the Early Permian. Four species are described and illustrated: Lagenoisporites triunfensis, L. scutiformis, Sublagenicula cf. brasiliensis, and Setosisporites cf. furcatus. Of these, the two species of Lagenoisporites are predominant. Relationships to other megaspore species are discussed; and the temporal and spatial distributions of the four species in the Paraná Basin are documented.

RICARDI-BRANCO FRESIA; ARAI MITSURU; RÖSLER OSCAR

2002-01-01

151

A Temnospondyl amphibian from the Rio do Rasto Formation, Upper Permian of southern Brazil  

Directory of Open Access Journals (Sweden)

Full Text Available A partially preserved lower jaw constitutes the holotype of Bageherpeton longignathus n. g., n. sp., a probable archegosaurid amphibian, which is here assigned to the Platyoposaurinae. The material was collected in the beds of the Rio do Rasto Formation outcropping in Rio Grande do Sul State, southern Brazil. This is the second archegosaurid described for the Permian of Brazil. Prionosuchus plummeri Price 1948, from the Pedra do Fogo Formation in the Parnaiba Basin (northeastern Brazil), is the first. The new taxon differs from other platyoposaurs by the presence of an extremely elongated precoronoid that participates in the mandibular symphysis.

DIAS ELISEU V.; BARBERENA MARIO C.

2001-01-01

152

Permian Basin, Texas: Volume 1, Text: Final preliminary design report  

International Nuclear Information System (INIS)

This report is a description of the preliminary design for an Exploratory Shaft Facility (ESF) at the proposed 49 acre site located 21 miles north of Hereford, Texas in Deaf Smith County. Department of Energy must conduct in situ testing at depth to ascertain the engineering and environmental suitability of the site for further consideration for nuclear waste repository development. The ESF includes the construction of two 12-ft diameter engineered shafts for accessing the bedded salt horizon to conduct in situ tests to ascertain if the site should be considered a candidate site for the first High Level Nuclear Waste Repository. This report includes pertinent engineering drawings for two shafts and all support facilities necessary for shaft construction and testing program operation. Shafts will be constructed by conventional drill-and-blast methods employing ground freezing prior to shaft construction to stabilize the existing groundwater and soil conditions at the site. A watertight liner and seal system will be employed to prevent intermingling of aquifers and provide a stable shaft throughout its design life. 38 refs., 37 figs., 14 tabs

1988-01-01

153

Permian Basin, Texas: Volume 1, Text: Final preliminary design report  

Energy Technology Data Exchange (ETDEWEB)

This report is a description of the preliminary design for an Exploratory Shaft Facility (ESF) at the proposed 49 acre site located 21 miles north of Hereford, Texas in Deaf Smith County. Department of Energy must conduct in situ testing at depth to ascertain the engineering and environmental suitability of the site for further consideration for nuclear waste repository development. The ESF includes the construction of two 12-ft diameter engineered shafts for accessing the bedded salt horizon to conduct in situ tests to ascertain if the site should be considered a candidate site for the first High Level Nuclear Waste Repository. This report includes pertinent engineering drawings for two shafts and all support facilities necessary for shaft construction and testing program operation. Shafts will be constructed by conventional drill-and-blast methods employing ground freezing prior to shaft construction to stabilize the existing groundwater and soil conditions at the site. A watertight liner and seal system will be employed to prevent intermingling of aquifers and provide a stable shaft throughout its design life. 38 refs., 37 figs., 14 tabs.

1988-01-01

154

Pumping test and fluid sampling report - Mansfield No. 1 (PD-4) well, Palo Duro Basin, Texas: unanalyzed data  

International Nuclear Information System (INIS)

This report contains pumping test and fluid sampling data collected at Mansfield No. 1 well, located in Oldham County, in the Permian Basin of Texas. These data were collected by Stone and Webster Engineering Corporation to support studies of fluid migration and age relationships in the Permian Basin. The testing and sampling took place between October 1981 and October 1982. These data are preliminary. They have been neither analyzed nor evaluated. 4 references, 8 figures, 2 tables

1981-10-00

155

Depositional environment of Lower Permian Stone Corral Formation  

Energy Technology Data Exchange (ETDEWEB)

The Lower Permian Stone Corral Formation is a 5-8 ft thick unit of dolomitic limestone and shale in a sequence of red beds that crops out in south-central Kansas. It forms a good stratigraphic marker bed in the subsurface, where it consists mainly of anhydrite (the Cimmaron anhydrite) up to 100 ft thick. At outcrop, the formation is weathered and consists of 2 interfingering facies - a crinoidal-echinoidal grainstone (in the north) and a laminated mudstone (in the south). Both the grainstone and mudstone exhibit diagenetic alteration. The grainstone is composed of well-rounded allochems of crinoid and echinoid fragments with scattered ooids, sponge spicules, peloids, and possible foraminifers and ostracods. Layers of sponge spicules alternate with peloid or ooid layers. The mudstone facies has a clotted texture and has laminations defined by the occurrence of fenestral fabric and peloids. Dolomite occurring in the Stone Corral Formation is of secondary origin. The grainstone is interpreted as being lagoonal in origin, whereas the mudstone facies is interpreted as supratidal. The grumous (clotted) texture may indicate phreatic diagenesis. The absence of anhydrite on outcrop, where it was presumably leached by surface waters leaving the less soluble dolomite, is additional evidence for a regional disconformity above the unit on the eastern side of a large, shallow, evaporitic basin.

Hylton, A.K.; Merriam, D.F.

1985-02-01

156

Tectonic control of geological hazards in the Northern Sydney Basin  

Energy Technology Data Exchange (ETDEWEB)

A structural model for the formation of the northeastern margin of the Sydney Basin is presented. This model envisages that during the Permian and Triassic, the northeastern part of the Sydney Basin, (encompassing the Gunnedah, Hunter Valley and Newcastle Coalfields) developed as a foreland basin to the rising New England Orogen lying to the east and north east. The relationship of this model to the Australian coalfields is described. 69 refs., 5 figs.

Beckett, J.; Glen, D. [Geological Survey of New South Wales, NSW (Australia)

1997-12-31

157

Distribution of Permo-Carboniferous clastics of Greater Arabian basin  

Energy Technology Data Exchange (ETDEWEB)

Strikingly correlative sequences of sediments composed of sandstones, siltstones, shales, and thin argillaceous carbonate beds are present, practically everywhere, underlying the Late Permian carbonates in the Greater Arabian basin. The Greater Arabian basin as defined here occupies the broad Arabian Shelf that borders the Arabian shield. This basin is composed of several smaller basins. These clastics are exposed as thin bands and scattered small exposures in several localities around the margins of the basin. The Permo-Carboniferous clastics are represented by the Unayzah Formation of Arabia, the Doubayat Group of Syria, the Hazro Formation of southeast Turkey, the Ga'arah Formation of Iraq, the Faraghan Formation of southwest Iran, and the Haushi Group of Oman. A Late Carboniferous-Early Permian age is assigned to these clastics because they contain fossil plants and palynomorphs. These sediments represent time-transgressive fluctuating sea deposits following a phase of regional emergence, erosion, and structural disturbance which preceded the Permian transgression. The basal contact of these clastics is marked by a well-pronounced angular unconformity with various older units, ranging in age from early Carboniferous to late Precambrian. This regional unconformity is probably related to the Hercynian movements. The upper contact is conformable with the Permian carbonates. The porous sandstones of the Permo-Carboniferous sediments are important hydrocarbon exploration targets. These reservoir rocks sometimes overlie mature source rocks and are capped by shales, marls, and tight carbonates. Significant quantities of hydrocarbons are contained in these reservoirs in different parts of the Greater Arabian basin.

Al-Laboun, A.A.

1987-05-01

158

Petroleum geology of the Palo Duro Basin, Texas Panhandle  

Energy Technology Data Exchange (ETDEWEB)

The Palo Duro Basin, Permian Basin, Texas is an asymmetric, relatively shallow, intracratonic basin in the southern Texas Panhandle filled mostly by Mississippian, Pennsylvanian, and Permian sedimentary rocks. Although deeper and prolific prolific petroleum-producing basins adjoin it on the north (Anadarko Basin), south (Midland Basin), and east (Hardeman Basin), the Palo Duro Basin has produced remarkably small amounts of oil and gas to date. This is all the more noteworthy because the sedimentary sequence and rock types of the basin are similar to those of the adjacent basins. Analyses of the stratigraphic succession and structural configuration of the Palo Duro Basin suggest that adequate reservoir rocks, top-seals, and geologic structures are present. Most of the structures formed early enough to have trapped hydrocarbons if they were migrating in the rock column. Although additional work is under way to properly address the question of the petroleum source rocks, generation, and migration, the general absence of production in the basin may relate to an overall deficiency in hydrocarbon generation within the basin. Geologic information in this report will form part of the basis for further analysis and conclusions on hydrocarbon potential in the Palo Duro Basin.

Rose, P.R.

1986-03-01

159

Petroleum geology of the Palo Duro Basin, Texas Panhandle  

International Nuclear Information System (INIS)

The Palo Duro Basin, Permian Basin, Texas is an asymmetric, relatively shallow, intracratonic basin in the southern Texas Panhandle filled mostly by Mississippian, Pennsylvanian, and Permian sedimentary rocks. Although deeper and prolific prolific petroleum-producing basins adjoin it on the north (Anadarko Basin), south (Midland Basin), and east (Hardeman Basin), the Palo Duro Basin has produced remarkably small amounts of oil and gas to date. This is all the more noteworthy because the sedimentary sequence and rock types of the basin are similar to those of the adjacent basins. Analyses of the stratigraphic succession and structural configuration of the Palo Duro Basin suggest that adequate reservoir rocks, top-seals, and geologic structures are present. Most of the structures formed early enough to have trapped hydrocarbons if they were migrating in the rock column. Although additional work is under way to properly address the question of the petroleum source rocks, generation, and migration, the general absence of production in the basin may relate to an overall deficiency in hydrocarbon generation within the basin. Geologic information in this report will form part of the basis for further analysis and conclusions on hydrocarbon potential in the Palo Duro Basin

1986-01-01

160

Porosity distribution in San Andres Formation (Permian), Cochran and Hockley Counties, Texas  

Energy Technology Data Exchange (ETDEWEB)

The lower San Andres Formation in Cochran and Hockley Counties, Texas, is one of the most prolific hydrocarbon-bearing horizons of the Permian basin. It is a cyclic sequence of shallow-water carbonates and evaporites which prograded across the northwest shelf toward the Midland and Delaware basins. San Andres production results from the vertical stacking of porous dolomite reservoirs. Stratigraphic trapping of hydrocarbons results from porosity pinch-outs defined by the degree of dolomitization and anhydrite plugging, both vertically near the top of depositional cycles, and on a regional scale. Stratigraphic trapping, combined with subtle structural nosing and changes in dip, define the limits of production. Reservoir zones are regionally correlatable and mappable. Major productive trends pinch out northward onto the Matador arch, defining this feature as a major influence on San Andres deposition and production.

Cowan, P.E.; Harris, P.M.

1986-06-01

 
 
 
 
161

Paleosalinity of permian nonmarine deposits in antarctica.  

UK PubMed Central (United Kingdom)

Argillites of the Permian Mount Glossopteris Formation were analyzed for clay minerals, trace elements, and phosphate paleosalinity. Mainly degraded and stripped illites occur. The determined salinity range, 29 to 33 parts per mille is designated the "paleosalinity signature" of the formation. Analysis of trace elements supports phosphate paleosalinity determinations. Data from Leaia-bearing beds indicate a salinity range of 30 to 31 parts per mille that persisted some 137 years. Subsequent increase to 33 parts per mille corresponded to termination of leaiid occupancy of the area. These findings confirm and extend Nelson's study of phasphate paleosalinity.

Tasch P; Gafford EL

1968-06-01

162

Regional distribution and chemical characterization of Permian Capitan fore-reef slope dolomite: Implications for paleohydrology  

Energy Technology Data Exchange (ETDEWEB)

Dolomitized fore-reef slope facies recently have become significant targets for petroleum exploration in the Permian basin and elsewhere. Despite this, very little is known about the dolomitization process that largely controls porosity distribution in this facies. An integrated field, petrographic, and geochemical study has been conducted in the fore-reef slope strata of the Permian Capitan Formation to provide insight into this problem. Dolomitization of the Capitan fore-reef slope facies ranges from 0 to 100%. Regionally, the variation is related to stratigraphic age, with older forereef slope facies more dolomitized than younger facies. This generalization is consistent throughout the Guadalupe Mountains and appears to continue into the subsurface. On a local scale, more permeable beds were the first dolomitized, and within these, dolomitization decreases downslope. In the Capitan reef facies, dolomitization is restricted to vertical karst breccia pipes and other zones of high primary porosity. The majority of Capitan dolomite is finely crystalline (5-30 {mu}) with average {delta}{sup 18}O = 0.9 and {delta}{sup 13}C = 5.9. A second coarser (130-{mu}) dolomite generation is also present but is not as volumetrically important. The relative positive (for the Late Permian) {delta}{sup 18}O values indicates an evaporitively concentrated dolomitizing fluid. The most likely paleohydrologic model for the main phase of forereef slope dolomitization calls for descending hypersaline brines passing through the reef facies in vertical karst breccia pipes and then following permeable beds down the foreslope. Several sources are possible for these brines, with the most likely being the hypersaline back-reef lagoonal environment.

Melim, L.A. (Southern Methodist Univ., Dallas, TX (USA))

1990-05-01

163

South Pacific Sedimentary Basins  

Energy Technology Data Exchange (ETDEWEB)

The geological development of the South Pacific can be viewed through four quite discrete time windows. The first is the main assembly of Gondwana in the Precambrian and Palaeozoic, we are still far from getting a coherent basin story, so no attempt was made to include Palaeozoic basins. The second window, early Permian through early Cretaceous, provides the great bulk of the rock that underpins mainland New Zealand, the Chatham Rise and the Norfolk Ridge. Apparently, non-stop subduction saw the creation and eventual amalgamation of at least five discrete subduction-related terranes and one abduction-related terrane. The original configurations, locations and relationships of these terranes have yet to be established, but by the early Cretaceous they were all assembled and docked with Gondwana. Subduction lingered but by the middle Cretaceous the region had entered the third window, the era of great extension and spreading of marginal basins. Gondwana had been breaking apart for a long time, but the New Zealand-Australia-Antarctica segment had remained intact. The local break-up was heralded by rifting followed by thermal relaxation and widespread passive margin subsidence. All the major marginal basins of the southwest Pacific formed then. Convergent margins were far away and the great bulk of New Zealand's coal, limestone and hydrocarbon source rocks were deposited. At the end of the Oligocene period the Pacific Ring of Fire propagated rapidly southward from Tonga into the North Island, and the region reverted to convergent margin status. Regression coal basins occurred. The fourth section of the book describes some basins with a dual history, initial deposition during the great extensional phase, followed by deposition relating to Neogene convergence. These include the region's major hydrocarbon basin, Taranaki Basin the Chatham Rise, the Challenger Plateau and the Great South Basin.

Ballance, P.F. (ed.) (University of Auckland, Auckland (New Zealand). Geology Department)

1993-01-01

164

Environmental mutagenesis during the end-Permian ecological crisis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

During the end-Permian ecological crisis, terrestrial ecosystems experienced preferential dieback of woody vegetation. Across the world, surviving herbaceous lycopsids played a pioneering role in repopulating deforested terrain. We document that the microspores of these lycopsids were regularly rele...

Visscher, Henk; Looy, Cindy V.; Collinson, Margaret E.; Brinkhuis, Henk; van Konijnenburg-van Cittert, Johanna H. A.

165

XII international congress on Carboniferous and Permian geology and stratigraphy  

Energy Technology Data Exchange (ETDEWEB)

Contains abstracts of papers and posters presented at the 12th international congress. Various aspects of Carboniferous and Permian geology and stratigraphy throughout the world are covered, including coal seams and oil shales.

1991-01-01

166

Synecology of lower Permian Qixia Formation in Hunan and Guangxi  

Energy Technology Data Exchange (ETDEWEB)

The fossils found in lower Permian Qixia Formation in Hunan and Guangxi often appear in typical associations. Each of these associations indicates the ecological factors of the environments in which they were formed. This paper describes the organic compositions and ecological character of these associations and discusses their significance in environmental analysis. According to the synecological analysis of these associations, some paleogeographic inferences of Hunan and Guangxi in Lower Permian Qixia stage have been drawn. 7 refs., 8 figs.

Liu, Z. (Xiangtan Mining Institute (China). Geology Department)

1992-06-01

167

Radiaxial fibrous calcite as early-burial, open-system cement: isotopic evidence from Permian of China  

Energy Technology Data Exchange (ETDEWEB)

The Nanpanjiang basin of south China occupies about 100,000 km/sup 2/ in southern Guizhou and eastern Yunnan Provinces and northwestern Guangxi Autonomous Region. This basin contains a thick Paleozoic carbonate sequence overlain by about 3000 m of Triassic basinal deposits. Permian carbonate rocks comprise a large portion of the Paleozoic strata and form several platforms separated by basins containing dark, thin-bedded limestones, siliceous shales, and cherts. The platform margins are rimmed by sponge or algal reefs. Radiaxial fibrous calcite (RFC) is the most abundant cement in very coarse sponge or algal debris of Upper Permian reef and fore-reef sediments exposed along the western margin of the nanpanjiang basin. Small volumes of syndepositional cement,s interpreted to have been fibrous magnesium calcites and botryoidal aragonite, predate RFC. Coarse, blocky burial calcite postdates RFC. Evidence that RFC was precipitated during sediment deposition was not found. RFC occurs as isopach layers up to 15 mm thick and exhibits white, gray, and black bands about 1 mm wide. The presence of microdolomite inclusions in these cements indicates that they were originally magnesium calcites. delta/sup 18/O of RFC cements are more positive than any of the earlier or later components of the reef and fore-reef facies. Analyses of successive bands reveals the most positive delta/sup 18/O near the center of the isopach layers. delta/sup 13/C of successive bands reveals generally more negative values toward the centers of layers. RFC layers are interpreted to have precipitated during early burial of the platform margin while reef and fore-reef sediments were in communication with seawater. Cement layers recorded isotopic characteristics of seawater as platform-edge sediments subsided through the water column at the basin margin.

Halley, R.B.; Scholle, P.A.

1985-02-01

168

Biostratigraphic correlation in the Karoo: The case of the Middle Permian parareptile Eunotosaurus  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english The richness of fossil tetrapods from the Beaufort Group of South Africa has enabled biostratigraphic subdivision of this Permo-Triassic succession, with global applicability. Despite being the thickest of the seven biozones recognised, attempts at further subdivision of the Middle Permian Tapinocephalus Assemblage Zone (Abrahamskraal Formation) have not been successful, largely because the exact stratigraphic ranges of fossil taxa are unknown. This gap in knowledge has l (more) imited stratigraphic correlation of the Abrahamskraal Formation and hindered understanding of Middle Permian Karoo basin development. Currently, the lowermost Beaufort Group is split between an eastern and a western stratigraphic scheme and, because of poor outcrop and the relative paucity of fossils in the east, stratigraphic correlation between the two areas has been uncertain. Recent fossil discoveries of the parareptile Eunotosaurus africanus in the Eastern Cape and Free State provinces have extended its known geographic range in the east. An additional specimen from the lower Middleton Formation in the Eastern Cape has, for the first time, enabled the biostratigraphic correlation of this unit with the Poortjie Member of the Teekloof Formation in the west. These finds confirm the diachroneity of the boundary between the marine Ecca Group and the terrestrial Beaufort Group.

Day, Mike; Rubidge, Bruce; Almond, John; Jirah, Sifelani

2013-01-01

169

Geotectonic implications of Permian and Triassic carbonate successions in the Central Plain of Thailand  

Science.gov (United States)

Two carbonate successions constituting Paleozoic–Mesozoic basement rocks distributed in the Nakhon Sawan–Uthai Thani area in the Chao Phraya Central Plain of Thailand were investigated to understand basic geotectonic subdivision of the area. Of them, we newly proposed the term Khao Pathawi Limestone for a Triassic succession exposed in eastern Uthai Thani Province, from which a rich foraminiferal fauna consisting of Aulotortus sinuosus, A. friedli, Tetrataxis inflata, Diplotermina subangulata, Agathammina austroalpina, Ammobaculites rhaeticus, Alpinophragmium perforatum, Gaudryina triadica, and others was discriminated. They clearly suggest a Late Triassic age and highly probably Norian/Rhaetian. This limestone succession is considered to have formed a carbonate platform and is comparable to those on the Triassic Lampang–Phrae Basin in the Sukhothai Zone of Northern Thailand. In contrast, the Uthai Thani Limestone exposed just west of the Khao Pathawi Limestone, in the form of NNW–SSE trending monadnocks, represents a slightly metamorphosed, thick-bedded Permian succession. Its outcrop alignment is distinct from the north–south trending Khao Pathawi Limestone, suggesting their structural separation. The Uthai Thani Limestone is correlated to the Sai Yok Formation and the Ratburi Limestone, both of which are well-known as typical Permian successions on the Sibumasu Block. By integrating these data from the carbonates, together with available geological information from other Paleozoic–Mesozoic basement units in the Central Plain, such as petrochemical properties of granitoids and volcanic/volcaniclastic rocks and litho- and chronostratigraphic characteristics of sedimentary successions, including the Permian Khao Gob Chert, we explain that the central part of the Nakhon Sawan–Uthai Thani area where the Khao Pathawi Limestone and the Khao Gob Chert are distributed, corresponds geotectonically to the direct southern extension of the Sukhothai Zone of Northern Thailand. Thus, as is the case of Northern Thailand, we recognized three geotectonic domains also in the Central Plain; they are the Indochina Block (part of Cathaysialand), Sukhothai Zone (Permian–Triassic island arc system), and Sibumasu Block (part of Gondwanaland) from east to west. To the south, the Sukhothai Zone probably extends to the Klaeng Zone of Southeast Thailand. In this paper, Endotriada martiniae Ueno, Miyahigashi and Charoentitirat, n. sp. from the Khao Pathawi Limestone is also described.

Ueno, Katsumi; Miyahigashi, Akira; Kamata, Yoshihito; Kato, Miyako; Charoentitirat, Thasinee; Limruk, Seranee

2012-11-01

170

Paleothermometry of the Sydney Basin  

Energy Technology Data Exchange (ETDEWEB)

Evidence from overprinting of magnetizations of Late Permian and Mesozoic rocks and from the rank of Permian coals and Mesozoic phytoclasts (coal particles) suggests that surface rocks in the Sydney Basin, eastern Australia, have been raised to temperatures of the order of 200 /sup 0/C or higher. As vitrinite reflectance, an index of coal rank or coalification, is postulated to vary predictably with temperature and time, estimates of the paleotemperatures in the Sydney Basin based on observed vitrinite reflectance measurements can be made in conjunction with reasonable assumptions about the tectonic and thermal histories of the basin. These estimates give maximum paleotemperatures of present day surface rocks in the range 60--249 /sup 0/C, depending on factors such as location in the basin, the thickness of the sediment eroded, and the maximum paleogeothermal gradient. Higher coal rank and, consequently, larger eroded thicknesses and paleogeothermal gradients occur along the eastern edge of the basin and may be related to seafloor spreading in the Tasman Sea on the basin's eastern margin. A theory of thermal activation of magnetization entailing the dependence of magnetic viscosity on the size distribution of the magnetic grains is used to obtain an independent estimate of the maximum paleotemperatures in the Sydney Basin. This estimate places the maximum paleotemperature in the range 250--300 /sup 0/C along the coastal region. Both coalification and thermal activation of magnetization models provide strong evidence of elevated paleotemperatures, which in places exceed 200 /sup 0/C, and the loss of sediment thicknesses in excess of 1 km due to erosion.

Middleton, M.F.; Schmidt, P.W.

1982-07-10

171

Glacial-eustatic sea-level fluctuation curve for Carboniferous-Permian boundary strata based on outcrops in the North American Midcontinent and North-Central Texas  

Energy Technology Data Exchange (ETDEWEB)

Based on lithologic and faunal analysis of uppermost Carboniferous through Lower Permian strata (Wabaunsee through lower Chase groups) exposed from southeastern Nebraska through north-central Oklahoma, a preliminary glacial-eustatic sea-level fluctuation curve is presented herein. In addition to the sea-level curve presented for the Midcontinent region, one for coeval outcropping strata (middle and upper Cisco Group) of the Eastern Shelf of the Midland Basin is also presented based on similar criteria. This sea-level curve is derived from new field studies as well as a refinement of earlier curves presented by Harrison (1973), and Boardman and Malinky (1985). The conclusion on the nature of the Carboniferous-Permian boundary strata cyclothems in the Midcontinent is mirrored by the results of that from North-Central Texas. Each of the primary biostratigraphically-based picks for the Carboniferous-Permian boundary coincide with either intermediate of major cycles in both study areas. Utilization of a glacial-eustatic maximum transgressive event for the Carboniferous-Permian boundary should result in a more correlatable level for intercontinental correlation.

Boardman, D.R. (Oklahoma State Univ., Stillwater, OK (United States). School of Geology)

1993-02-01

172

Volcanically induced environmental change at the Permian–Triassic boundary (Xiakou, Hubei Province, South China): Related to West Siberian coal-field methane releases?  

Science.gov (United States)

A detailed geochemical investigation of the Permian–Triassic boundary in a carbonate-ramp setting at Xiakou, South China, provides new insights regarding the role of volcanism in the largest mass extinction in Earth history. The Xiakou section records 9 intervals of volcanic activity, some producing up to 25-cm-thick composite ash layers, during the latest Permian and earliest Triassic. Each volcanic episode coincided with major changes in marine environments. The largest changes occurred in conjunction with volcanic interval VI-4, correlative with the latest Permian mass extinction, during which (1) the oceanic oxygen-minimum zone expanded (as shown by framboidal pyrite flux), (2) marine productivity declined sharply (as shown by multiple productivity proxies), and (3) climate conditions became more humid (as shown by increased clay fluxes). The mechanism by which volcanic eruptions forced marine environmental changes may be inferred from the relationship between ash layer thickness and the magnitude of the associated negative C-isotope excursion. The most likely connection is through volcanogenic methane release to the atmosphere, possibly as a result of magmatic intrusions into the West Siberian Coal Basin, triggering increases in global temperature and humidity. These climate changes in turn resulted in stronger oceanic stratification, oxygen-minimum zone expansion, and a decline in marine productivity. The Xiakou section is important in demonstrating links between volcanism and the marine environment during the Permian–Triassic transition interval.

Shen, Jun; Algeo, Thomas J.; Feng, Qinglai; Zhou, Lian; Feng, Lanping; Zhang, Ning; Huang, Junhua

2013-10-01

173

Capitan reef complex (Permian), Guadalupe Mountains, southwestern United States: a classic sedimentologic model in flux  

Energy Technology Data Exchange (ETDEWEB)

The Capitan reef complex of west Texas and New Mexico has been an important sedimentologic model since a reef origin was proposed for the Capitan Limestone in 1929. The Capitan's magnificent exposures in the Guadalupe Mountain area; its large scale; its variety of carbonate, sandstone, and evaporite facies; and its relationship to major petroleum resources of the Permian basin have made it a justly famous sedimentary geologic model for academic and industrial geologists alike. Since 1950, extensive research has yielded markedly contrasting sedimentologic interpretations of key features, such as the nature and origin of the Capital massive (reef wall); the back-reef pisolite, sandstone, and evaporite facies; the depositional profile of the shelf and shelf edge; the importance and magnitude of sea level fluctuations; and the role of submarine, vadose, and phreatic diagenesis.

Pray, L.C.

1987-11-01

174

Seismic facies of the Permian section of the Barents Shelf: analysis and interpretation  

Energy Technology Data Exchange (ETDEWEB)

Hydrocarbon exploration has been intensively conducted on the Barents Shelf during the last 10 years. The main target consisted of the Mesozoic section and, more recently, of the Palaeozoic section. Only a limited number of deep wells and shallow cores have been used to investigate the Palaeozoic succession on the elevated areas of the shelf. However, dense and often high-quality seismic data covering the entire shelf permit the extrapolation of the sporadic well control to the entire basin. The Palaeozoic succession of the Barents Shelf has been investigated with data from only a few wells. However, a considerable amount of high-quality seismic data complements the sporadic well control, permitting an extensive seismic study of the three major intervals distinguished in the Permian section. (author).

Gerard, J.; Buhrig, C. (Fina Exploration Norway, Stavanger (NO))

1990-08-01

175

Plant biodiversity in the Mahanadi Basin, India, during the Gondwana period  

Energy Technology Data Exchange (ETDEWEB)

The Mahanadi Basin is one of five major sedimentary basins of Peninsular India. The sediments are exposed in two different regions: an extensive basin comprising Lower to Upper Gondwana with coal measures towards the west (Talchir and Ib-River Sub-basins); and the Athgarh Sub-basin in the east with rocks of only Upper Gondwana age. This study was mainly concerned with plant species diversification and the development of flora in the Mahanadi Basin from the Early Permian to the Early Cretaceous. A number of successive megafloras were recognised with gaps in the sequence. Leaves were the dominant part of the preserved flora, followed by fruits. Maximum plant diversification in gymnosperms was recorded in the Late Permian (Kamthi Formation), and in pteridophytes in the Early Cretaceous (Athgarh Formation).

Singh, K.J. [Birbal Sahni Institute of Paleobotany, Lucknow (India)

2000-07-01

176

Rayn formation, a new name for the permian khuff formation (s. S.) In saudi arabia ????? ????? ? ??? ???? ?????? ???? (?????? ) ??????? ??????? ?? ??????? ??????? ????????  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The rank of the Khuff Formation (late Carboniferous-late Permian) in Saudi Arabia is raised to group status and it is divided into Unayzah (late Carboniferous-early Permian) and Rayn (middle-late Permian) Formations. The name Rayn Formation is suggested as a new term to replace the Khuff Formation s...

El Nakhal, Hamed A. [???? ???? ??????

177

Volcanic perturbations of the marine environment in South China preceding the latest Permian mass extinction and their biotic effects.  

UK PubMed Central (United Kingdom)

The Dongpan section in southern Guangxi Province records the influence of local volcanic activity on marine sedimentation at intermediate water depths (~200-500 m) in the Nanpanjiang Basin (South China) during the late Permian crisis. We analyzed ~100 samples over a 12-m-thick interval, generating palynological, paleobiological, and geochemical datasets to investigate the nature and causes of environmental changes. The section records at least two major volcanic episodes that culminated in deposition of approximately 25- to 35-cm-thick ash layers (bentonites) and that had profound effects on conditions in both the Dongpan marine environment and adjacent land areas. Intensification of eruptive activity during each volcanic cycle resulted in a shift toward conifer forests, increased wildfire intensity, and elevated subaerial weathering fluxes. The resulting increase in nutrient fluxes stimulated marine productivity in the short term but led to a negative feedback on productivity in the longer term as the OMZ of the Nanpanjiang Basin expanded, putting both phytoplankton and zooplankton communities under severe stress. Radiolarians exhibit large declines in diversity and abundance well before the global mass extinction horizon, demonstrating the diachroneity of the marine biotic crisis. The latest Permian crisis, which was probably triggered by the Siberian Traps flood basalts, intensified the destructive effects of the earlier local eruptions on terrestrial and marine ecosystems of the South China craton.

Shen J; Algeo TJ; Zhou L; Feng Q; Yu J; Ellwood B

2012-01-01

178

Volcanic perturbations of the marine environment in South China preceding the latest Permian mass extinction and their biotic effects.  

Science.gov (United States)

The Dongpan section in southern Guangxi Province records the influence of local volcanic activity on marine sedimentation at intermediate water depths (~200-500 m) in the Nanpanjiang Basin (South China) during the late Permian crisis. We analyzed ~100 samples over a 12-m-thick interval, generating palynological, paleobiological, and geochemical datasets to investigate the nature and causes of environmental changes. The section records at least two major volcanic episodes that culminated in deposition of approximately 25- to 35-cm-thick ash layers (bentonites) and that had profound effects on conditions in both the Dongpan marine environment and adjacent land areas. Intensification of eruptive activity during each volcanic cycle resulted in a shift toward conifer forests, increased wildfire intensity, and elevated subaerial weathering fluxes. The resulting increase in nutrient fluxes stimulated marine productivity in the short term but led to a negative feedback on productivity in the longer term as the OMZ of the Nanpanjiang Basin expanded, putting both phytoplankton and zooplankton communities under severe stress. Radiolarians exhibit large declines in diversity and abundance well before the global mass extinction horizon, demonstrating the diachroneity of the marine biotic crisis. The latest Permian crisis, which was probably triggered by the Siberian Traps flood basalts, intensified the destructive effects of the earlier local eruptions on terrestrial and marine ecosystems of the South China craton. PMID:22051197

Shen, J; Algeo, T J; Zhou, L; Feng, Q; Yu, J; Ellwood, B

2011-11-03

179

Source potential and sequence stratigraphic characterization of microbial evaporitic mudrocks: Upper Permian Zechstein Group, Northern Germany  

Science.gov (United States)

Microbial evaporitic carbonate mudrocks are important source rocks throughout much of the earth history. Some of the largest hydrocarbon provinces are potentially sourced by evaporite source rocks such as the Cretaceous and Jurassic in the Middle East, the Tertiary in Spain, the Permian in northern Germany, the Devonian in Canada, and the Pennsylvanian in the USA. Carbonate mudrocks deposited under mesosaline conditions are often over-looked and dismissed as potential source rocks. However, preservation and accumulation of organic matter in salinity-layered intraplatform epeiric depressions and restricted basin centers are significant. These mudrocks may not only constitute the source but also exhibit reservoir qualities. Slope and basin laminated mudrocks were investigated for their source and reservoir potential using sequence stratigraphic and geochemical techniques to investigate the exploration potential of the northern German Upper Permian Zechstein Formation. The lower Zechstein cycles Z1 and Z2 are characterized by calcareous to argillaceous, laminated, organic-rich mudstones with TOC (total organic carbon) contents ranging mostly 6% in the Z1 cycle. Maturities range from 0.9 to >3% Ro depending on depth of burial for these two cycles. While the Z1 mudrocks deposited above the Rotliegend clastic section are more argillaceous and clay-rich grading upward from calcareous mudstones to intraclast, coated grain, thrombolitic wacke- and packstones into coated-grain grainstones, the Z2 mudrocks are dominated by calcareous to dolomitic laminated mudstones. Both cycles are characterized by microbially bound carbonates ranging from thrombolytic to crenulated laminated structures that are overlain by anhydrite and salt. Stacking patterns of the Z1 3rd-order cycle reveal three 5th-order parasequences stacking into two 4th-order sequences; Z2 3rd-order cycle is composed of three 4th-order parasequences that first deepen and then shallow upwards. Sediments associated with deepening events contain the highest amount of TOC and maturities along the slope and basin. The configuration of the two Zechstein cycles within this epeiric basin favored accumulation of microbial source rocks, carbonate reservoirs and evaporite seals.

Hammes, Ursula; Mutti, Maria

2013-04-01

180

The Permian mega floras of Uruguay.A synthesis  

International Nuclear Information System (INIS)

The Permian megafloras of Uruguay. A synthesis. An analysis of the impression and fossil wood floras from the Permian of Uruguay is given through a series of Tables. These show : (1) the list of taxa, (2) anatomical characters of the woods, (3) data on the microfloral associations, (4) paleoenvironmental information and (5) comparisons with contemporaneous Gondwana floras. The evolutionary degree of the woods is briefly analyzed where they correspond to the so-called ''transition xilotaphofloras'' as they present typical Paleozoic anatomical characters but with secondary xylem of more advanced characteristics. (author)

2007-01-01

 
 
 
 
181

Permian plants from the Chutani Formation (Titicaca Group, Northern Altiplano of Bolivia): II. The morphogenus Glossopteris  

Directory of Open Access Journals (Sweden)

Full Text Available Fossil plants belonging to the morphogenera Glossopteris, Pecopteris and Asterotheca were collected from the upper part of the Chutani Formation (Titicaca Group), near the town of San Pablo de Tiquina, on the southeastern shore of Lake Titicaca (northern Altiplano, Bolivia). This paper presents the first description of specimens of the morphogenus Glossopteris from Bolivia. The Bolivian specimens of Glossopteris consist of poorly-preserved impressions, although they present the diagnostic features of this morphogenus. They are fragments of leaves with secondary veins of taeniopterid-type, typical of glossopterids from Late Permian deposits of Gondwana. The only species of Pecopteris confirmed in the first part of this study, i.e. P. dolianitii Rösler and Rohn (see Vieira et al. 2004), was previously reported from the Late Permian beds of the Rio do Rasto and Estrada Nova formations in the Paraná Basin (southern Brazil). Therefore, a Late Permian age is proposed for the fossil plant-bearing beds of the Chutani Formation based on the analyzed assemblage. The phytogeographic implications of this new find are briefly analyzed.Plantas fósseis, pertencentes aos morfo-gêneros Glossopteris, Pecopteris e Asterotheca, foram coletadas na porção superior da seção aflorante da Formação Chutani, próxima ao povoado de San Pablo de Tiquina, sudeste do lago Titicaca (Altiplano norte, Bolívia). Este trabalho apresenta a primeira descrição de espécimes do morfo-gênero Glossopteris provenientes da Bolívia. Os espécimes estudados de Glossopteris consistem em impressões foliares pobremente preservadas nas quais feições diagnósticas estão presentes. Os fragmentos foliares apresentam venação secundária do tipo teniopteróide, uma característica típica de glossopterídeas encontradas em depósitos do Permiano Superior do Gondwana. Por sua vez, a única espécie de Pecopteris confirmada para estes níveis da Formação Chutani, i.e. P. dolianitii Rohn and Rösler (ver Vieira et al. 2004), foi previamente assinalada para estratos do Permiano Superior da Bacia do Paraná (formações Estrada Nova e Rio do Rasto). Portanto, uma idade neopermiana é tentativamente proposta para os níveis da Formação Chutani que contém a associação estudada. As implicações fitogeográficas deste novo achado são brevemente analisadas.

Roberto Iannuzzi; Carlos E. L. Vieira; Margot Guerra-Sommer; Enrique Díaz-Martínez; George W. Grader

2004-01-01

182

Influence of Permian salt dissolution on distribution of shallow Niobrara gas fields, eastern Colorado  

Energy Technology Data Exchange (ETDEWEB)

Subsurface analysis of Permian salt and related strata in the shallow Niobrara gas area on the eastern flank of the Denver basin reveals that the location of faulted anticlines which produce gas from porous chalk is related to the occurrence of six Nippewalla Group (Leonardian) salt zones. Salt distribution is controlled by the configuration of evaporate basins during the Leonardian, truncation at a sub-Jurassic unconformity (which has completely removed Guadalupian salts), and post-Jurassic subsurface dissolution. Significant dissolution took place in response to Laramide orogeny and subsequent eastward regional groundwater flow within the Lyons (Cedar Hills) Sandstone aquifer. Initially, dissolution occurred along a regional facies change from sandstone to salt. Solution collapse allowed for cross-formational flow and removal of younger salts. Shallow Niobrara gas fields are situated above salt outliers or along regionally updip salt edges. No significant Niobrara production exists in areas where salt is absent. Structural relief across fields is related to Leonardian thickness variations, rather than subsalt offset. Seismic data reveal abrupt Leonardian thinning at the regionally updip limit of Eckley field, which has produced over 33 BCFG. Thickness of residual salt may be important in controlling the amount of gas trapped within the Niobrara. Where thick salts are preserved, structural relief is greater, the gas-water transition zone is thicker, and gas saturation is higher at the crests of faulted anticlines.

Oldham, D.W.; Smosna, R.A. [West Virginia Univ., Morgantown, WV (United States)

1996-06-01

183

Chronostratigraphic assignment, based in Strontium isotopes (87 Sr/86 Sr) from the Andira Formation (Amazon Basin) and Cruzeiro do Sul Formation (Acre Basin), Brazil  

International Nuclear Information System (INIS)

This paper presents some Sr isotope data (87 Sr/86 Sr ratios) from the Andira Formation (Amazon Basin) and Cruzeiro do Sul Formation (Acre Basin) in Northern Brazil. For the first one the analyzed materials were anhydrite found in the median portion of the stratigraphic unit. Limestones samples in the basal portion were the rocks studied in the second unit. The results suggest, respectively, the Sakmarian and Asselian/Sakmarian stages for their depositions, both in the Lower Permian.

1997-01-01

184

Hydrocarbon accumulations in the Tarim basin, China  

Energy Technology Data Exchange (ETDEWEB)

The Tarim basin is the largest and least explored inland basin in China. The areal extent of the basin reaches 560,000 km{sup 2}. The interior of the basin is mostly covered by the Takla Mekan Desert, which is about 330,000 km{sup 2} in areal extent. The basin has become the object of special attention since China set aside first- and third-round onshore bidding blocks in the Tarim basin for foreign oil firms to explore. The Tarim basin is a polyhistory superimposed basin that has experienced seven evolutionary stages: (1) Sinian-Cambrian-Ordovician aulacogen stage, (2) Silurian-Devonian intracratonic depression stage, (3) Carboniferous marginal sea stage, (4) Permian rift basin stage, (5) Triassic-Jurassic foreland basin stage, (6) Cretaceous-Paleogene NeoTethys bay stage, and (7) Neogene-Pleistocene foreland and inland basin stage. Both the basin`s Paleozoic marine platform sequences and the Mesozoic-Cenozoic terrestrial fills are believed to contain substantial volumes of hydrocarbons. After recent years of exploration, nine oil and gas fields have been proven and 23 discoveries have been made in the Tabei, Tazhong, and Southwest areas. Kekeya, Lunnan, Sangtamu, Jiefangqudong, Donghetang, and Tazhong 4 oil fields have been put into production. Output of crude oil was 2.6 million t (metric tons) (52,000 BOPD) in 1995. The production will increase to 5 million t (100,000 BOPD) in 1997. Giant oil and gas traps probably will be discovered in the Tarim basin. The prospect is promising.

Li Desheng [Research Institute of Petroleum Exploration and Development, Beijing (China); Liang Digang; Jia Chengzao; Wang Gang [Tarim Petroleum Exploration and Development Bureau, Korle (China)] [and others

1996-10-01

185

Paleohydrology of the Anadarko Basin, central United States  

Science.gov (United States)

Geohydrologic systems in the Anadarko basin in the central United States are controlled by topography, climate, geologic structures, and aquifer hydraulic properties, all of which are the result of past geologic and hydrologic processes, including tectonics and diagenesis. From Late Cambrian through Middle Ordovician time, a generally transgressive but cyclic sea covered the area. The first deposits were permPable sand, followed by calcareous mud. During periods of sea transgression, burial diagenesis decreased porosity and permeability. During periods of sea recession, uplift diagenesis increased porosity and permeability, especially in exposed rocks. During most of Silurian and Devonian time, the sea receded; increased porosity and permeability resulted from uplift diagenesis. However, at the end of the Devonian and during the Early Mississippian, very slightly permeable clay, which now is a regional confining unit, was deposited in a mostly euxinic sea. Later during Mississippian time, calcareous muds, which became limestone, were deposited in and adjacent to the Anadarko basin and underwent burial diagenesis. During Pennsylvanian time, rapid sedimentation accompanied rapid subsidence in the Anadarko basin. A geopressure zone probably resulted when sediments with little permeability trapped depositional water in Lower Pennsylvanian sands. Burial diagenesis included compaction and thermal alteration of deeply buried organic material, which released carbon dioxide, water, and hydrocarbons. By Middle Pennsylvanian time, the sea had submerged most of the central United States, including the Ozarks, as tectonic activity reached its maximum. During Late Pennsylvanian and Early Permian time, the Ouachita uplift had been formed and was higher than the Ozarks. Uplift was accompanied by a regional upward tilt toward the Ouachita-Ozarks area; the sea receded westward, depositing large quantities of calcareous mud and clay, and precipitating evaporitic material in the restricted-circulation environment. By the end of Permian time, > 20,000 ft of Pennsylvanian and Permian sediments had been deposited in the Anadarko basin. These thick sediments caused rapid and extreme burial diagenesis, including alteration of organic material. During Permian time in the Ozarks area, development of the Ozark Plateaus aquifer system commenced in the permeable Cambrian-Mississippian rocks near the St. Francois Mountains as the Pennsylvanian confining material was removed. Since Permian time, uplift diagenesis has been more active than burial diagenesis in the Anadarko basin. Synopsis of paleohydrologic interpretation indicates that Cambrian-Mississippian rocks in the Anadarko basin should be relatively impermeable, except for local secondary permeability, because rocks in the basin have undergone little uplift diagenesis.

Jorgensen, Donald G.

1989-01-01

186

Fold superimposition in the Permian groups in the central Beishan orogenic collage (northwestern China): highlights for the late evolution of the Altaids  

Science.gov (United States)

The southernmost part of the Central Asian Orogenic Belt (CAOB) or Altaids (Sengör and Burtman, 1993; Xiao et al., 2009), a rare and magnificent example of mesoscopic fold superimposition, involving the Permian sandstone, slightly to mildly metamorphosed clastic rocks, is well exposed in the central Beishan Orogenic Collage (BOC). We provide a detailed description of the morphological features of this phenomenon, based on an enormous amount of structural data collected during recent twice field mapping in the study area. Two phases of folds are readily distinguishable both in satellite image (Fig.la) and our own field map (Fig.1b). Fold is tight to close, N-S-trending in the first phase (F1), and open and E-W-trending in the second phase (F2). The first phase upright folds were refolded into a smaller number of (F2), whose axial planes and axes are vertical or subvertical. They plunge gentle to moderately in the former and moderately to steeply in the latter. Their interference is in general categorized as Ramsay's (Ramsay, 1967) type 2 or Ghosh's third/fourth mode based on the value of initial tightness. However, from east to west there exists a slight variation of a zigzag to crescent to mushroom interference pattern. This subtle variation corresponds with the westward increases of the F2 interlimb angle and of the percentage of coarse-grain clastic rocks, suggesting its dependence upon the F2 deformation and the lithology. Axial slaty cleavages (S1) and associated dip-slip slickensides are more abundant in the first phase. Cleavages and strike-slip slickensides related to the seconding refolding are also occurred in the area. Finally, according to the petrological, geochemical and geochronological data, we conclude that the deformation history of the superposed folds were associated with the late evolution in the BOC. In the late Permian, the fold superimposition occurred in sedimentary rocks deposited in a Permian back-arc basin. The basin was intensely inverted, when the Huaniushan arc collided presumably obliquely with the Tarim block in late Permian, to the west, and with the Duanhuang block in the Early to Middle Triassic. The latter collision eventually ended the evolution of the BOC. In interpretation, these collisions produced an earlier local E-W and later regional N-S compressions for the fold superimposition. Finally, the mafic dyke with the age of 219 Ma intruding the refolded Permian rocks post-dates the two stages of deformation.

Zhonghua, Tian; Wenjiao, Xiao; Yehua, Shan

2013-04-01

187

The formation of Serra Alta, Teresina and Rio do Rasto, Brazil, in the SP-23-PR (Permian, Passa Dois group, and the eastern border of the Parana basin) borehole; As Formacoes Serra Alta, Teresina e Rio do Rasto no furo de sondagem SP-23-PR (Permiano, Grupo Passa Dois, Borda Leste da Bacia do Parana)  

Energy Technology Data Exchange (ETDEWEB)

The borehole SP-23-PR of the CPRM company, located in Congonhinhas-PR (UTM coord. 7374.863N/545.384E at an altitude of 953,64m), has the longest cored interval of the Passa Dois Group, in the eastern border of the Parana Basin. The Serra Alta and the Teresina formations and the Serrinha Member of the Rio do Rasto Formation, in an approximately 600 m long vertical succession, were analysed with emphasis to the lithofaciology and to the lithostratigraphic boundaries. Almost the whole interval is siliciclastic, but there are many carbonatic intercalations, which were studied in detail. The borehole shows a gradual contact between the Serra Alta and Teresina formations, suggesting a transition from distal and low energy environments to shallow or coastal settings of an interior sea, dominated by storm waves, in an intracratonic large basin. The carbonates of the Teresina Formation are decimetric, mainly micritic and oosparitic, frequently impure and amalgamated, with abundant ostracodes and endemic bivalves, correlationable for long distances (according to the interpreted other borehole wireline logs), and they were probably originated during drier climatic intervals. The boundary between the Teresina and the Rio do Rasto formations is abrupt, probably discordant, characterized by the appearance of thick sandstones, but still occurring micritic and coquine intercalations. There also appear abundant fossil conchostracans, which indicate continental aquatic environments. (author)

Rohn, Rosemarie; Lourenco, Augusto Tortolero Araujo [UNESP, Rio Claro (Brazil)]. E-mail: rohn@rc.unesp.br; atal20@bol.com.br; Meglhioratti, Thiago [UNESP, Rio Claro (Brazil). Dept. de Geologia]. E-mail: madmaxth@yahoo.com.br

2003-07-01

188

A comparison of fusible inertinite in Carboniferous and Permian coals  

Energy Technology Data Exchange (ETDEWEB)

It is generally agreed that the demarcation between fusible and infusible macerals does not coincide with the vitrinite/inertinite boundary but is situated within the range of low-reflecting inertinite. In the widely accepted Schapiro-Gray system of coke stability calculations, 1/3 of semifusinite is considered to be fusible, but the imposition of such a rigid fusibility cut-off failed to give correct estimates of coke stability indices in past ICCP ring analyses of Permian and Cretaceous coals. This failure was due to an underestimation of the high degree of fusibility of a considerable percentage of inertinite group macerals. Since the Schapiro-Gray method is based on Carboniferous coals, it is possible that coals of other ages and origins contain different proportions of infusible and fusible inertinite. Alternatively, different coals may have similar proportions of infusible and fusible inertinite, but they could differ in the actual levels of thermoplasticity. Having established a close link between the fusibility of inertinite and its optical properties, we used microfluorescence intensity and reflectance of inertinite as a measure of the degree of fusibility. No significant differences were found in inertinite fluorescence between the two sets of coals when fresh samples were compared. Likewise, the study revealed no difference in the reflectance distribution of inertinite between Carboniferous and Permian coals, which raises the question whether the underestimation of inertinite reactivity by the Schapiro-Gray method applies to Carboniferous coals as much as it does to Permian coals. 38 refs., 7 figs., 1 tab.

Diessel, C.F.K.; Gammidge, L.C. [University of Newcastle, Newcastle, NSW (Australia). Dept. of Geology

1995-12-31

189

Spiral-shaped graphoglyptids from an Early Permian intertidal flat  

Science.gov (United States)

Spiral-shaped foraging trace fossils, assigned to the grapho glyptid cf. Spirorhaphe azteca, are reported from an Early Permian intertidal flat in the Robledo Mountains of southern New Mexico, USA. Remarkably similar spiral-shaped structures are produced in modern intertidal flats by the paraonid polychaete Paraonis fulgens, and function as traps to capture mobile microorganisms migrating in the sediment in response to tides. We envisage a similar function for the Early Permian trace fossils. Previous studies have suggested that the lack of P. fulgens type traces from ancient intertidal deposits indicates that such behavior only evolved geologically recently in such settings. However, this report demonstrates that such specialized foraging behavior was present in intertidal settings by at least the Early Permian. Graphoglyptids are typical of deep-marine settings, and characteristic of the Nereites ichnofacies. This represents their first undoubted occurrence in intertidal facies in the geological record. We postulate that the occurrence of graphoglyptids in deep-marine and intertidal settings is related to the predictability of resources. The scarcity of intertidal graphoglyptids in the geological record is most likely a preservational effect.

Minter, Nicholas J.; Buatois, Luis A.; Lucas, Spencer G.; Braddy, Simon J.; Smith, Joshua A.

2006-12-01

190

Thecamoebians from Late Permian Gondwana sediments of peninsular India.  

UK PubMed Central (United Kingdom)

The evolutionary history of thecamoebians (testate amoebae) extends back to the Neoproterozoic Era. However, until now, these have had a restricted, discontinuous and modest record across the world. The studied sediment of Raniganj Formation (Godavari Graben), Andhra Pradesh, India has been assigned as Late Permian on the basis of co-occurring age-diagnostic Late Permian palynomorphs. About sixteen thecamoebian species and one taxon incertae sedis have been recorded here in the palynological slides on the basis of shell morphology and morphometry. Out of these, five belong to the family Arcellidae, seven to Centropyxidae, two to Trigonopyxidae, one to Difflugiidae, one to Plagiopyxidae, and one is regarded incertae sedis. The morphometric characteristics of fossil forms resemble their corresponding extant species studied from ecologically diverse fresh water wetlands in India. In general, the ratio of shell diameter and aperture diameter of Late Permian fossil and extant specimens show significant correlation in all the studied species. Except that, the ratio of shell length and breadth is the distinguishing feature between Centropyxis aerophila and C. aerophila 'sylvatica', rather than the ratio of shell length and longest diameter of the shell aperture in both fossil and extant forms. The study elucidates the minimal morphological evolution in thecamoebians and their survival during mass extinction periods and stressful environmental conditions over the geological timescale.

Farooqui A; Aggarwal N; Jha N

2013-07-01

191

Permian plants from the Chutani Formation (Titicaca Group, Northern Altiplano of Bolivia): I. Genera Pecopteris and Asterotheca  

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Full Text Available Fossil plants belonging to the morphogenera Glossopteris, Pecopteris and Asterotheca were collected from the upper part of the Chutani Formation (Titicaca Group), near the town of San Pablo de Tiquina, on the southeastern shore of Lake Titicaca (northern Altiplano, Bolivia). Here we report the analysis of fern-type foliage found at this location. Three species of pecopterid fronds are identified: Pecopteris dolianitii Rohn and Rösler, P. cf. P. cadeadensis Rohn and Rösler, and P. cf. P. pedrasica Read. All these species are typically found in Permian deposits of the Paraná Basin in southern Brazil. Despite the poor preservation of the material, a fertile specimen could be studied and was determined as Asterotheca sp. The paleoenvironmental and paleoecological implications of this new find are briefly analyzed.

Vieira Carlos E. L.; Iannuzzi Roberto; Guerra-Sommer Margot; Díaz-Matrínez Enrique; Grader George W.

2004-01-01

192

Thermal state of the Arkoma Basin and the Anadarko Basin, Oklahoma  

Science.gov (United States)

One of the most fundamental physical processes that affects virtually all geologic phenomena in sedimentary basins is the flow of heat from the Earth's interiors. The Arkoma Basin and the Anadarko Basin, Oklahoma, are a prolific producer of both oil and natural gas. Both basins also have important geologic phenomena. Understanding the thermal state of the these basins is crucial to understanding the timing and extent of hydrocarbon generation, the genesis of Mississippi Valley-type ore deposits, and the origin of overpressures in the Anadarko Basin. In chapter one, heat flow and heat production in the Arkoma basin and Oklahoma Platform are discussed. Results of this study are not generally supportive of theories which invoke topographically driven regional groundwater flow from the Arkoma Basin in Late Pennsylvanian-Early Permian time (˜290 Ma) to explain the genesis of geologic phenomena. In chapter 2, different types of thermal conductivity temperature corrections that are commonly applied in terrestrial heat flow studies are evaluated. The invariance of the relative rankings with respect to rock porosity suggests the rankings may be valid with respect to in situ conditions. Chapter three addresses heat flow and thermal history of the Anadarko Basin and the western Oklahoma Platform. We found no evidence for heat flow to increase significantly from the Anadarko Basin in the south to the Oklahoma Platform to the north. In chapter four, overpressures in the Anadarko Basin, southwestern Oklahoma are discussed. Using scale analyses and a simple numerical model, we evaluated two endmember hypotheses (compaction disequilibrium and hydrocarbon generation) as possible causes of overpressuring. Geopressure models which invoke compaction disequilibrium do not appear to apply to the Anadarko Basin. The Anadarko Basin belongs to a group of cratonic basins which are tectonically quiescent and are characterized by the association of abnormal pressures with natural gas. (Abstract shortened by UMI.)

Lee, Youngmin

1999-12-01

193

Caribbean basin framework, 4: Maracaibo basin, northwestern Venezuela  

Energy Technology Data Exchange (ETDEWEB)

The Maracaibo basin is presently located in a topographic depression on the Maracaibo block, a triangular, fault-bounded block within the Caribbean-South America plate boundary of northwestern Venezuela. Intense oil exploration over the last 50 years has produced a large amount of seismic and well data that can be used to constrain four Jurassic to Recent tectonic and depositional events that affected the region: (1). Late Jurassic rift phase and subsidence along normal faults striking north-northeast across the floor of the basin; (2) Cretaceous to early Eocene subsidence recorded by shallow to deep marine carbonate and clastic rocks that thicken from south to north and completely cover Permian rocks of the Merida arch; (3) Eocene folding, thrusting, and initial reactivation of Jurassic normal faults as convergent strike-slip and reverse faults. Eocene clastic sediments are thickest in a narrow northwest-trending foredeep on the northeastern margin of the basin; (4) Late Miocene to Recent northwest-southeast convergence is marked by continued reactivation of Jurassic normal faults as reverse and left-lateral strike-slip faults, uplift of mountain ranges bordering the basin, and deposition of up to 10 km of clastic sediment.

Lugo, J. (Univ. of Texas, Austin (United States))

1991-03-01

194

A preliminary study of REE distributions in mudrocks of Permian Beacon Supergroup, Central Transantarctic Mountains  

Energy Technology Data Exchange (ETDEWEB)

Partial REE patterns have been determined for ten Permian mud-rock samples from the central Transantarctic Mountains. Depositional environments of the samples range from fluvial overbank to open-water deltaic and basinal. REE patterns have beeh characterized by a LREE enrichment factor (EF), defined as the NASC-normalized La/Lu ratio. The response of LREE to weathering intensity, thermal diagenesis, and compositional variability has been assessed. Average LREE EF for the ten samples is 2.00 (+-0.6), similar to published LREE EF for recent riverine and marine siliciclastics. This agreement suggests that the LREE EF of a sediment is established early in its weathering/transport history. LREE EF do not covary with either an index of chemical weathering of vitrinite reflectance, indicating that LREE are not fractionated by either bulk weathering processes or diagenesis. LREE EF increases as grain size decreases and clay mineral abundance increases. Geographic variations in LREE EF, however, may also reflect a provenance control. These stratigraphic and geographic distributions of LREE EF emphasize the importance of grain size and mineralogy as controls on REE compositions, but also suggest that the early development of LREE enrichment can include a stable provenance signal.

Krissek, L.A.; Horner, T.C.

1988-01-01

195

Megaspores from coals of the Triunfo Member, Rio Bonito Formation (Lower Permian), northeastern Paraná State, Brazil  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents the results of a detailed study of megaspores occurring in coal seams of the Triunfo Member, Rio Bonito Formation at Figueira, Paraná State, Brazil. This coal-bearing sequence accumulated in a marine delta system during the Early Permian. Four species are described and illustrated: Lagenoisporites triunfensis, L. scutiformis, Sublagenicula cf. brasiliensis, and Setosisporites cf. furcatus. Of these, the two species of Lagenoisporites are predominant. Relationships to other megaspore species are discussed; and the temporal and spatial distributions of the four species in the Paraná Basin are documented.No presente trabalho são apresentados os resultados obtidos a partir do estudo sistemático detalhado dos megásporos provenientes das camadas de carvão do Membro Triunfo, Formação Rio Bonito, Estado do Paraná, Brasil. A seqüência portadora de carvão, foi o resultado do acúmulo de matéria orgânica num de sistema deltaico marinho durante o Eopermiano. Quatro espécies são aqui descritas e ilustradas: Lagenoisporites triunfensis, L. scutiformis, Sublagenicula cf. brasiliensis, e Setosisporites cf. furcatus. Destas, as duas espécies de Lagenoisporites são dominantes. São igualmente discutidas as relações existentes com outras espécies de megásporos, assim como documentada a distribuição temporal e espacial das quatro espécies na Bacia do Paraná.

FRESIA RICARDI-BRANCO; MITSURU ARAI; OSCAR RÖSLER

2002-01-01

196

A Temnospondyl amphibian from the Rio do Rasto Formation, Upper Permian of southern Brazil  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Uma mandíbula parcialmente preservada constitui o holótipo de Bageherpeton longignathus n. g., n. sp., um provável anfíbio arquegossaurídeo aqui considerado como um Platyoposaurinae. O material foi coletado nas camadas da Formação Rio do Rasto que afloram no Estado do Rio Grande do Sul, no sul do Brasil. Este é o segundo arquegossaurídeo descrito para o Permiano do Brasil. O primeiro é Prionosuchus plummeri Price 1948, da Formação Pedra de Fogo na Bacia do Par (more) naíba (nordeste do Brasil). O novo taxon difere dos outros platiopossauros pela presença de um pre-coronóide extremamente longo que participa da sínfise mandibular. Abstract in english A partially preserved lower jaw constitutes the holotype of Bageherpeton longignathus n. g., n. sp., a probable archegosaurid amphibian, which is here assigned to the Platyoposaurinae. The material was collected in the beds of the Rio do Rasto Formation outcropping in Rio Grande do Sul State, southern Brazil. This is the second archegosaurid described for the Permian of Brazil. Prionosuchus plummeri Price 1948, from the Pedra do Fogo Formation in the Parnaiba Basin (north (more) eastern Brazil), is the first. The new taxon differs from other platyoposaurs by the presence of an extremely elongated precoronoid that participates in the mandibular symphysis.

DIAS, ELISEU V.; BARBERENA, MARIO C.

2001-03-01

197

A Temnospondyl amphibian from the Rio do Rasto Formation, Upper Permian of southern Brazil  

Directory of Open Access Journals (Sweden)

Full Text Available A partially preserved lower jaw constitutes the holotype of Bageherpeton longignathus n. g., n. sp., a probable archegosaurid amphibian, which is here assigned to the Platyoposaurinae. The material was collected in the beds of the Rio do Rasto Formation outcropping in Rio Grande do Sul State, southern Brazil. This is the second archegosaurid described for the Permian of Brazil. Prionosuchus plummeri Price 1948, from the Pedra do Fogo Formation in the Parnaiba Basin (northeastern Brazil), is the first. The new taxon differs from other platyoposaurs by the presence of an extremely elongated precoronoid that participates in the mandibular symphysis.Uma mandíbula parcialmente preservada constitui o holótipo de Bageherpeton longignathus n. g., n. sp., um provável anfíbio arquegossaurídeo aqui considerado como um Platyoposaurinae. O material foi coletado nas camadas da Formação Rio do Rasto que afloram no Estado do Rio Grande do Sul, no sul do Brasil. Este é o segundo arquegossaurídeo descrito para o Permiano do Brasil. O primeiro é Prionosuchus plummeri Price 1948, da Formação Pedra de Fogo na Bacia do Parnaíba (nordeste do Brasil). O novo taxon difere dos outros platiopossauros pela presença de um pre-coronóide extremamente longo que participa da sínfise mandibular.

ELISEU V. DIAS; MARIO C. BARBERENA

2001-01-01

198

Dolomitization in permiah rocks in Sichuan Basin  

Energy Technology Data Exchange (ETDEWEB)

The Permian System in Sichuan basin is composed of shallow water carbonate rocks deposited on a platform in a warm and humid climate with very fluorishing biota. Dolomitization occurred under the following circumstances: (1) replacement by large coarse-grained dolomites along the fractures and pores; (2) replacement by small rhombohedral dolomites along the suture lines and (3) replacement by large coarse-grained dolomites of fresh-saline water origin. The last mentioned dolomites predominate the other two, with the ancient carbonate rock upland of biolith origin in neighboring provinces playing the controlling role.

Zhang, Y.

1982-01-01

199

Thermal maturation pattern in the southern Bowen, northern Gunnedah and Surat Basins, northern New South Wales, Australia  

Energy Technology Data Exchange (ETDEWEB)

Comprehensive maximum vitrinite (telocollinite) reflectance data have been obtained for more than 260 polished sections from 28 petroleum exploration wells in the southern Bowen and northern Gunnedah Basins, and the overlying Surat Basin, in an area from north of Boggabri to the New South Wales-Queensland border. The samples studied were coal and dispersed organic matter (DOM) taken from ditch cuttings and drill cores of the Permian, Triassic and Jurassic sedimentary successions. Vitrinite reflectance profiles show that the coals and DOM in the Early Permian Back Creek Group of the southern Bowen Basin have anomalously low (suppressed) reflectance values and a higher reflectance gradient (rate of increase in vitrinite reflectance with depth) relative to the overlying Late Permian, Triassic and Jurassic sequences. Suppression of vitrinite reflectance is recorded in the Early Permian Maules Creek and Goonbri Formations in the northernmost part of the Gunnedah Basin, relative to the overlying Triassic and Jurassic sequences. Dispersed organic matter in the marine sediments of the Watermark and Porcupine Formations of the Gunnedah Basin also shows suppression of vitrinite reflectance. The vitrinite in several wells of the study area, however, displays anomalously high reflectance in parts of the sequence due to the influence of igneous intrusions. After allowing for heat effects due to intrusions and anomalies due to marine influence, the reflectance gradient over equivalent intervals in the southern Bowen Basin is higher towards the west, where the Permian sequence pinches out and the Triassic sequence overlies the basement. Vitrinite reflectance also increases at a higher rate with depth close to the Gil Gil Ridge in the east and close to the Moree High in the south. This may reflect additional heat flow associated with the basement high features. The areas between the Gil Gil Ridge and the Goondiwindi Thrust in the east, and to the west of the Gil Gil Ridge, appear to have lower reflectance gradients, and equivalent or lower reflectance values despite the greater burial depths.

Othman, Rushdy; Ward, Colin R. [School of Geology, University of New South Wales, NSW 2052 Sydney (Australia)

2002-08-01

200

Mid-Permian shelf margin erosion surfaces, western escarpment, Guadalupe Mountains, Texas  

Energy Technology Data Exchange (ETDEWEB)

Three basin-sloping erosion surfaces, interpreted as submarine seismic sequence boundaries, are spectacularly exposed along the Guadalupe Mountains' western escarpment. Each surface has about 300 m of basin margin relief over 2 to 3 km and displays 30 to 80 m of local channeling and/or listric-shaped relief. The upper (post-Grayburg) and lower (post-Victorio Peak) surfaces truncate predominantly flat-bedded, shoaling-upward bank (or low-angle ramp) dolomite strata. The middle surface (post-Cutoff) locally cuts through the deep marine drape of 300 m relief of the 75-m thick Cutoff formation. The post-Grayburg surface is listric-shaped and truncates about 140 m of Grayburg in a basinward distance of 1.5 km. This post-Grayburg erosion surface marks a major change in Permian carbonate sedimentation from earlier bank strata to the steep foreslopes of 400 + relief of the Goat Seep-Capitan reef complex. Erosional retreat of the Grayburg and Victorio Peak bank margin may have been 100 m to 1 km or more. Evidence of submarine erosion includes deep marine facies directly overlying the erosion surfaces, the regional improbability of hundreds of meters of sea level lowering, and the lack of recognition of subaerial or coastal features. The erosion processes remain uncertain. Retrograde slumping is favored for the listric-shaped post-Grayburg surface. Bottom-hugging density currents were likely important for the lower two surfaces and perhaps for all three surfaces. Bare and eroded slopes are increasingly being recognized in modern submarine environments. They are likely more abundant and important in the geologic record than has been recognized to date.

Franseen, E.K.; Pray, L.C.; Fekete, T.E.

1987-05-01

 
 
 
 
201

The Himalayan Lopingian Series (Late Permian) in Southern Tibet, China  

UK PubMed Central (United Kingdom)

Investigations into three Permian-Triassic sections (the Selong Xishan, Qubu and Tulong sections) suggest the widespread distribution of the Lopingian Series (Late Permian) and the continuous Permian-Triassic boundary in southern Tibet. The Lopingian series in southern Tibet is characterized by containing typical Gondwanatype brachiopods such as Taeniothaerus, Fusispirifer, Neospirifer (neopirifer) kubeiensis, Retimarginifera xizangensis and Spiriferella rajah, which suggest a correlation with those known from the upper part of the Wargal and Chhidru Formations in the Salt Range, Pakistan, the Zewan Formation in Kashmir, the Basleo Bed in West Timor, the Senja Formation in Northwest Nepal and the Hardman Formation in Western Australia. According to the occurrences of the conodont Clarkina dukouensis zone in the middle part of the Wargal Formation and the Clarkina longicuspidata zone in the lower part of the Chhidru Formation, and the association with the ammonoid Cyclolobus and the foraminifer Colaniella fauna in the Salt Range, the Selong Group in the Himalayan region, as a whole, is considered to be Lopingian in age. The Himalayan Lopingian Series represents a third-order sequence and can be divided roughly into two different sedimentary types. The Qubu-type Lopingian represents deposits developed in restricted coastal envionments along the northern peri-Gondwana continental margin. The Qubu Formation in the lower part consists mainly of quartzose sandstone interbedde with black shale containing the Glossopteris flora. The Qubuerga Formation in the upper part is composed of a siltstone- and bioclastic limestone-dominated member in the lower part with abundant brachiopods and a shale- and siltstone-dominated member in the upper part with the Atomodesma fauna and abundant terrestrial palynomorphs and acritarchs. The Selong-type Lopingian represents a sequence developed on the inner shelf and is composed of the Selong Group dominated by carbonates with numerous brachipods and a Waagenites bed in the lowest Kangshare Formation.

Shen Shuzhong; Cao Changqun; Wang Xiangdong; Mei Shilong; Jin Yugan

2002-01-01

202

Ocean redox change at the Permian-Triassic mass extinction  

DEFF Research Database (Denmark)

Earth’s history is marked by multiple events of ocean anoxia developing along continental margins and po¬tentially into the open ocean realm. These events of¬ten coincide with the emplacement of large igneous provinces (LIPs) on continents, major perturbations of global geochemical cycles and marine (mass) ex¬tinction. The geographic and temporal extend and the intensity (ferruginous vs. euxinic) of anoxic con¬ditions is, however, strongly debated and not well constraint. This complicates understanding of close coupling between Earth’s physical, chemical and bi¬ological processes. We studied ocean redox change over the largest mass extinction event in Earth history, at the Permian-Tri¬assic boundary (at ~252 Ma). This event is marked by a major perturbation in the global exogenic carbon cycle (and associated major negative carbon isotope excursion (CIE)), likely initiated by carbon outgassing from the Siberian Traps. We measured redox-sensitive trace element concentrations (e.g. Mo, Cu, U) and the speciation of iron [Fe-HR/Fe-T and Fe-PY/ Fe- HR] in marine sediments from Svalbard (Festningen). We compare these data to additional, new, high-lati-tude data from eastern Greenland and the equatorial Tethys realm in Iran. We show that the Permian-Tri¬assic boundary at Svalbard is marked by 2 phases of euxinic (sulfidic) ocean conditions. An initial short phase at the onset of atmospheric carbon release is separated from a subsequent longer phase by a re¬turn to ferruginous ocean conditions (anoxic but not euxinic) coinciding with the main extinction event. Molybdenum enrichments, often indicative for freely available sulfide in the water-column, only occur dur¬ing the second phase of euxinia. This pattern of ocean redox-change in Svalbard direct¬ly reflects similar trends in Greenland and Iran. It sug¬gests a strongly decreased global ocean molybdenum (and possibly also ocean sulfate) inventory by massive molybdenum drawdown (and possibly pyrite buri¬al) at the onset of end-Permian atmospheric carbon release and leading up to the Permian-Triassic mass extinction. We compare these oceanographic changes to similar observations for the Triassic-Jurassic mass extinction and discuss environmental forcing, poten¬tially inherent to major volcanic events and leading to global environmental change and extinction.

Ruhl, Micha; Bjerrum, Christian J.

203

Tectono-metamorphic map of the Mont Morion Permian metaintrusives (Mont Morion - Mont Collon - Matterhorn Complex, Dent Blanche Unit), Valpelline - Western Italian Alps  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The presented map displays the structural and metamorphic evolution of lithotypes from pre-Permian to present. We distinguish pre-Permian rocks (e.g., amphibolite, biotite-bearing gneiss and acid granulite) preserved as roof pendants (i.e., xenoliths) within Permian intrusives. Permian intrusives an...

ZUCALI, MICHELE

204

Geology of principal Australia coals and coal basins: a review  

Energy Technology Data Exchange (ETDEWEB)

Bituminous or subbituminous coals are known from nearly all parts of Australia. Those of greatest economic importance today are found in the Permian and Triassic Bowen and Galilee basins of Queensland and the Sydney-Bowen basin of New South Wales, with some coalfields of lesser significance in the Clarence-Moreton basin in Queensland and New South Wales. Structural, sedimentary, and paleobiologic features of the coal-bearing strata and regional trends of various coal characteristics of some of the principal economic or geologically interesting basins and coals are reviewed and illustrated. These include the Hail Creek syncline, Goonyella, Peak Downs, German Creek, Blackwater, Baralaba, Tolmeis and Moura Mines of the Bowen basin. In New South Wales these include the Hunter Valley area Singleton Coal Measures represented by the Foyebrook-Liddell Seam and Ravensworth mines; the Newcastle area; the Ulan Seam of the Goulburn Valley area; the western shelf area and Sydney-Wollongong region represented by the Illawarra (Permian) Coal Measures which are overlain by the thick Triassic Narrabean Series, Hawksbury Sandstone, and Wianamatta Group. A paleobiologic analysis of the thick brown coal sequences in the Yallourn, Latrobe Valley, and Bacchus Marsh areas of Victoria, and the significance of tectonics in the development of these great coal swamps will be reviewed.

Cross, A.T.

1983-09-01

205

Mixing mechanisms in siliciclastic-carbonate successions of Khan Formation (Permian), Central Iran  

Science.gov (United States)

Mixing mechanisms in siliciclastic-carbonate successions of Khan Formation (Permian), Central Iran M. Shadan & M. Hosseini-Barzi Geology Department, Faculty of Earth Science, Shahid Beheshti University, Tehran, Iran shadangeo@gmail.com Mixing mechanisms in siliciclastic-carbonate successions of Khan Formation (Permian) have been studied in two sections (Chahroof with 197 m thick in north and Cheshmeh Bakhshi with 204 m thick in south) along basement Kalmard fault in Posht-e-Badam block, Central Iran. Siliciclastic units are characterized by well sorted, fine to medium grain quartzarenites with laterite interbeds, deposited in shoreline zone (foreshore, upper and lower shoreface) influencing wave and longshore currents. Longshore sands which have been transported along the coast made the sand bars in the shoreface. Further along the coast, returning of these currents as rip currents produced erosive channel inlets and caused to carry fine grain into the deeper regions of the basin. Based on this sedimentary model we introduced longshore currents as a probable agent for mixing, by transporting some volumes of sands into the adjacent carbonate environments. Vertically, clastic units of Khan Formation underlined by carbonate units of a tidal flat and high-energy inner ramp system. Repeating of this pattern produced 3 cycles in each section. Cyclic evolution, in studied sections, is accompanied with discrepancy in erosion and sedimentation. These factors caused to disperse local sub-aerial exposures in successions which are recognizable by laterite and conglomerate interbeds. These horizons of sub-aerial exposures are more often in Chahroof section than in Cheshmeh Bakhshi section and indicate more fluctuations of relative sea level probably due to more local tectonic activity in the northern part of the Kalmard fault than in the southern part of it. Also, thicker siliciclastic units in Chahroof section show higher rate of sediment supply and/or more accommodation space there. Moreover, the late Paleozoic glacial conditions in Gondwana lands supported the large volume of clastic supply into the basin by intense weathering and erosion of vast exposed regions in Posht-e-Badam block. Also, tectonic activity along Kalmard basement fault mainly controlled local sea level changes and lithology of outcrops in the hinterlands. Therefore, interplay of these factors during lowstand of relative sea level, with lower accommodation space and higher gradient led to high rate of sediment input and distribution of siliciclastics in the base of each cycles. In contrast, relative sea level rises have been corresponded to the more accommodation space and reducing of siliciclastic entrance into the sedimentary basin that made a suitable condition for carbonate production. Therefore, during relative sea level rise, verities of carbonate-producing organisms tend to more rates of biogenic carbonate products and eventually formation of carbonate units upon the preexistence silisiclastics. Therefore, mixing of siliciclastics with carbonate deposits in Khan Formation have mainly been controlled temporally by sea level fluctuations due to local and/or eustatic sea level changes and spatially by variations in local tectonic activities and lateral facies mixing by longshore currents.

Shadan, Mahdi; Hosseini-Barzi, Mahboubeh

2010-05-01

206

Polyphase tectonic events and Cenozoic basin-range coupling in the Tianshan Belt, Northwestern China  

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Studies show that the Tianshan orogenic belt was built in the late stage of the Palaeozoic, as evidenced by the Permian red molasses and foreland basins; which are distributed in parallel with the Tianshan belt, indicating that an intense folding and uplifting event took place. During the Triassic, this orogenic belt was strongly eroded, and basins were further developed. The folding and faulting of Mesozoic sedimentary rocks, spontaneous combustion of Jurassic coal layers and formation of sintered rocks, the Cenozoic earthquakes and active faulting, and the unique mosaic pattern of basin-range framework of Xinjiang are all products of tectonism since the Neogene.

Shu, L.S.; Wang, B.; Yang, F.; Lu, H.F.; Charvet, J.; Laurent-Charvet, S. [Nanjing University, Nanjing (China). Dept. of Earth Science

2003-12-01

207

Basaltic activity preserved in an Upper Permian radiolarian chert from the Paleo-Tethys in the Inthanon Zone, northern Thailand  

Science.gov (United States)

Basaltic sandstone composed mainly of clay- to sand-sized fragments of glass and basaltic rock has been discovered in a pelagic chert sequence in northern Thailand. The sandstone conformably underlies and is partly intercalated with the Upper Permian (Wuchiapingian-early Changhsingian) radiolarian-bearing chert. Geological age dating based on radiolarians, petrographic examination of the bedded chert with the basaltic sandstone, and geochemical studies were conducted to investigate the origin and sedimentary mode of the lithologic sequence. The bedded chert overlying the basaltic sandstone yielded Late Permian radiolarians and was correlatable with the Wuchiapingian Follicucullus charveti–Albaillella yamakitai assemblage zone as well as the early Changhsingian Neoalbaillella ornithoformis assemblage zone. Lithofacies and microfacies of the bedded chert indicated deposition in a pelagic realm of the Paleo-Tethys. Although the tectonic setting was difficult to estimate based on geochemical features because of element mobility and alteration, the basaltic fragments likely originated as oceanic basalt such as oceanic island basalt. Microfacies and sedimentary structures of the chert and sandstone indicated that the studied sequence is composed of intermittent high sedimentation rates, mainly gravity currents of basaltic fragments, in a background setting of very slowly accumulating radiolarian chert. The sedimentary mode of the sequence, the rare terrigenous influx, and the presence of fusulinoidean or other foraminiferal tests indicate that the basaltic rocks fragment were originally sourced from an oceanic topographic high such as a seamount or an oceanic plateau, and that the volcanic activity occurred in the chert-accumulated oceanic basin of the Paleo-Tethys in the Wuchiapingian.

Kamata, Yoshihito; Maezawa, Ayako; Hara, Hidetoshi; Ueno, Katsumi; Hisada, Ken-ichiro; Sardsud, Apsorn; Charoentitirat, Thasinee; Charusiri, Punya

2012-11-01

208

Molecular Evidence for Radical Changes in Ocean Chemistry Across the Permian Triassic Boundary at Meishan in South China  

Science.gov (United States)

Samples from outcrop and from a new core drilled through the Permian Triassic Boundary at the type section at Meishan have been examined for biomarker and isotopic evidence of biotic and associated environmental change. Late Permian sediments from Meishan Beds 22-27 are characterized by indicators of anoxia including low Pr/Ph ratios and abundant aryl isoprenoids and isoreneieratane derived from the precursor carotenoid isorenieratene. The latter compounds are biomarkers for green sulfur bacteria (Chlorobiaceae) and are considered reliable indicators of euxinic water columns where sulfide extends to the photic zone. The peak of Chlorobiaceae biomarker abundance coincides with a rapid and synchronous drop in the ƒO13C and ƒO15N values of kerogen. On passing up into the Early Triassic, the biomarker signal for Chlorobiaceae wanes and is almost absent by Bed 30 where it is replaced by one for cyanobacteria including abundant hopanes and 2-methylhopanes and accompanying methyl and dimethyl alkanes. A very high value for the hopane/sterane ratio from Beds 30-38 indicates continuing dominant cyanobacterial productivity and only minor inputs from an algal plankton. The prevalence of aryl isoprenoids in P-Tr sediments at the Meishan section of South China is also recorded in a recently cored borehole, Hovea-3, of the Perth Basin, Western Australia. This suggests similar paleoenvironmental conditions prevailed across the Tethys Ocean during and immediately after the P-Tr Boundary. In particular, the presence of biomarkers for Chlorobiaceae at two separate locations indicates that water column euxinia was pervasive during the extinction event and suggests that sulfide may have been a key toxic agent.

Love, G. D.; Cao, C.; Jin, Y.; Summons, R. E.

2004-12-01

209

The Cordon del Portillo Permian magmatism, Mendoza, Argentina, plutonic and volcanic sequences at the western margin of Gondwana  

Science.gov (United States)

The Cerro Punta Blanca, Cerro Bayo and Cerro Punta Negra stocks, parts of the Cordillera Frontal Composite Batholith, cropping out in the Cordón del Portillo, records the Gondwana magmatic development of the Cordillera Frontal of Mendoza, in western Argentina. In this area, the San Rafael Orogenic phase, that represents the closure of the Late Carboniferous-Early Permian marine basins, begins at 284 Ma, and ceased before 276 Ma. The Cerro Punta Blanca, Cerro Bayo and Cerro Punta Negra stocks represent a post-orogenic magmatism and are equivalents to the Choiyoi Group. The Gondwana magmatic activity in the Cordón del Portillo area can be divided into two stages. The Cerro Punta Blanca stock (c.a. 276 Ma) represents an early post-orogenic, subduction-related magmatism similar to the basic-intermediate section of the Choiyoi Group (c.a. 277 Ma). The late post-orogenic second event was recorded by the Cerro Bayo (262 Ma) and Cerro Punta Negra stocks which represent a transition between subduction-related and intra-plate magmatism. This event represents the intrusive counterpart of the acidic facies of the upper section of the Choiyoi Group (c.a. 273 Ma). This extensional condition continued during the Triassic when the Cacheuta basin developed.

Gregori, Daniel; Benedini, Leonardo

2013-03-01

210

Structural style and evolution of the Pechora basin, USSR  

Energy Technology Data Exchange (ETDEWEB)

The Pechora basin is the complexity structured foreland depression west of the Northern Urals. The majority of the large, commonly hydrocarbon-bearing, anticlinal structures within the basin on their relationship to the sub-Paleozoic basement and origin identified in high-resolution reflection seismic lines, two general classes of structures can be distinguished. The broad northwest-trending anticlinoria (Pechora-Kozhva, Kolva, and Sorokin swells) crossing the central and northern portions of the basin comprise en echelon anticlines formed above relatively steep basement-rooted faults. Folds of this group developed in the Permian, during the early phase of the Uralian orogeny, by left-lateral transpressional inversion of Late Devonian half-grabens that underlie the anticlinoria. The anticlinoria within the broad Timan Ridge, the southeast margin of the basin, may have a similar origin. A second group of fault propagation folds frames the basin on the east and northeast, comprising the frontal structures (Chernov, Chernyshov, and Vuktyl anticlines) of the Northern Urals and Pay-Khoy thrustbelts. Spatial relationships between the anticlinoria and associated thrusts in the Pechora basin and those in the frontal zone of the Northern Urals point to strong mechanical control of individual thrust sheets in the Urals by the northwest-trending middle Paleozoic rifts within the basin. Furthermore, spatial and timing relations suggest that all of the structures in the Pechora basin and Northern Urals root on a common, deep crustal detachment and that much, if not all, of the basin is allochthonous.

Malyshev, N.A.; Udin, V.V. (Komi Science Center, Syktyvkar, (USSR)); Schamel, S. (Univ. of South Carolina, Columbia (United States))

1991-08-01

211

The upper Paleozoic coalbed methane system in the Qinshui basin, China  

Energy Technology Data Exchange (ETDEWEB)

The coalbed methane resource is very abundant in Qinshui basin (3.28 x 10{sup 12} m{sup 3}; 114 tcf). The upper Paleozoic coalbed methane system in the Qinshui basin is sealed by a low-permeability roof and floor strata comprising mudstone, siltstone, and bauxite of the Carboniferous Benxi Formation and the Permian Shanxi and Xiashihezi formations. The overburden is the Lower Permian Xiashihezi Formation and the Upper Permian, Triassic, and Middle Jurassic clastic deposits. The source and reservoir rocks are the Carboniferous Permian coal seams. The hydrocarbon generation of the source rocks reached its first peak in the Late Triassic. The highest maturity was about R{sub o} = 1.2% under a normal paleogeothermal gradient (2-3{sup o}C/100 m; 1.1-1.7 {sup o}F/100 ft). A tectonic thermal event during the Jurassic and Cretaceous Yanshanian orogeny enhanced the coal maturity and caused a second peak of hydrocarbon generation. Varying igneous intrusions caused the coal maturity to be higher in the southern, northern, and eastern parts of the Qinshui basin instead of the central and western parts. The highest maturity was greater than R{sub o} = 4% in the Jincheng area. The migrated thermogenetic coalbed methane accumulated in the reservoirs in which abnormally high reservoir pressure exists locally under the hydrodynamic drive. Because of the different hydrodynamic background and sealing condition, the distribution of coalbed methane content is inhomogeneous. The reservoir is undersaturated with gas in most areas. Based on the coalbed methane system investigation we assessed, the coalbed methane producibility in different parts of the Qinshui basin, and the major producibility area is in the southern part of the basin.

Su, X.B.; Lin, X.Y.; Zhao, M.J.; Song, Y.; Liu, S.B. [Henan Polytechnic University, Henan (China)

2005-01-01

212

Aspects of thermal evolution of Anadarko basin, Oklahoma  

Energy Technology Data Exchange (ETDEWEB)

Individual microcline-bearing clasts in cores from depths of 2.17, 3.27, 3.34, 3.57, and 4.40 km provided to us by the Oklahoma Geological Survey yield /sup 40/Ar//sup 39/Ar age spectra showing a clear correlation for the Pennsylvanian-Permian granite wash between depth and radiogenic /sup 40/Ar (/sup 40/Ar*) loss, consistent with the expectation that the deeper parts of the Anadarko basin have experienced the higher temperatures. A less-expected result is that the initial ages in the five age spectra converge at approx. 100 Ma, indicating these samples were hot enough to cause diffusive loss of /sup 40/Ar* from the microcline lattice until as late as Albian times. Activation energies for this process are very similar to some of those involved in producing fluid hydrocarbons from organic matter. They therefore suggest that although there is good evidence of petroleum generation in the Anadarko basin by the end of the Permian, progressively larger volumes of source rock may have resided within the oil window in the Triassic to Early Cretaceous as the thick sediments of the basin warmed by conduction. Plateau ages indicate that temperatures as high as 180/sup 0/C were obtained during the Mesozoic in rocks now lying at a depth of about 4 km. The coherence of the age spectra strongly suggest abrupt uplift of the basin beginning 100 Ma moving perhaps 2 km of sediment by erosion.

Harrison, T.M.; Heizler, M.T.; Burke, K.

1987-05-01

213

Intrashelf basins: A geologic model for source-bed and reservoir facies deposition within carbonate shelves  

Energy Technology Data Exchange (ETDEWEB)

Intrashelf basins (moats, inshore basins, shelf basins, differentiated shelf, and deep-water lagoons of others) are depressions of varying sizes and shapes that occur within tectonically passive and regionally extensive carbonate shelves. Intrashelf basins grade laterally and downdip (seaward) into shallow-water carbonates of the regional shelf, are separated from the open marine basin by the shelf margin, and are largely filled by fine-grained subtidal sediments having attributes of shallow- and deeper water sedimentation. These basins are commonly fringed or overlain by carbonate sands, reefs, or buildups. These facies may mimic those that occur along the regional shelf margin, and they can have trends that are at a high angle to that of the regional shelf. Intrashelf basins are not intracratonic basins. The history of most intrashelf basins is a few million to a few tens of million of years. Examples of intrashelf basins are known throughout the Phanerozoic; the southern portion of the Holocene Belize shelf is a modern example of an intrashelf basin. Two types of intrashelf basins are recognized. Coastal basins pass updip into coastal clastics of the craton with the basin primarily filled by fine clastics. Shelf basins occur on the outer part of the shelf, are surrounded by shallow-water carbonate facies, and are filled by peloidal lime mud, pelagics, and argillaceous carbonates. Intrashelf basins are commonly the site of organic-rich, source-bed deposition, resulting in the close proximity of source beds and reservoir facies that may fringe or overlie the basin. Examples of hydrocarbon-charged reservoirs that were sourced by an intrashelf basin include the Miocene Bombay High field, offshore India; the giant Jurassic (Arab-D) and Cretaceous (Shuaiba) reservoirs of the Arabian Shelf; the Lower Cretaceous Sunniland trend, South Florida basin; and the Permian-Pennsylvanian reservoirs surrounding the Tatum basin in southeastern New Mexico.

Grover, G. Jr. (Sauid Aramco, Dhahran (Saudi Arabia))

1993-09-01

214

ON DISCOVERY OF THE GENUS CAULOPTERIS FROM THE LOWER PERMIAN IN WESTERN HENAN,CHINA  

UK PubMed Central (United Kingdom)

The Genus Caulopteris represents the fossil imprints remained on the trunk surface of the ferir tree after the fronds fell down .The fern trees are important coal making plants .Their fossil fronds are very wide-spread and abundant in the Late Paleozoic coal-fields .Their relic species still live in Indonesia and Guizhou Province of China?and are designated as the living fossils .It is clear now that almost all of them belong to the Filicopsida such as the genera Asterotheca?Acitheca or Ptychocarpus?Cyathea?etc .This does not rule out a few of them belonging to the Pteridospermopsida. On the contrary?fossils of the scars remained on the trunk surface of the ferir tree are very rare in the world.In China?specialists have only discovered 6 specimens of this kind.One of them was foundby Ha tae ,in 1931 ,from the?Wuhuzui Coal Field of Benxi City?Liaoning Province .The second was discovered from the Kaipin Basin of Hebei Province by Gunthner in 1936 and was known as C. manchuriensis Hatae .The third was found from Daqingshan of Inner Mongolia by Lee in 1963 and erected as a new species C.sinensis.Lee corrected Gunthner' s error and placed the his specimen in thenew species in Lee' s monograph .The fourth was discovered from the Junlian Coal-Field of Sichuan Province ,China and was described by Zhu et al .as C.sichuanensis.The fifth was found from East Hill of Taiyuan City by He et al who published it in their monograph( 1995) :this specimen belongs toC .sinensis Lee .The sixth occurred from the Jurassic?which is not discussed in this paper. At present ,the authors have found another complete specimen belonging to the genus Caulopteris from the Shanxi Formation of the Lower Permian in Shanyuan Village?Dengfeng County?western Henan Province of China .This new species is described as follows:

HeXilin; Sun Banian

1998-01-01

215

The Permian-Triassic mass extinction: Ostracods (Crustacea) and microbialites  

Science.gov (United States)

The end-Permian mass extinction (EPE), about 252 Myr ago, eradicated more than 90% of marine species. Following this event, microbial formations colonised the space left vacant after extinction of skeletonised metazoans. These post-extinction microbialites dominated shallow marine environments and were usually considered as devoid of associated fauna. Recently, several fossil groups were discovered together with these deposits and allow discussing the palaeoenvironmental conditions following the EPE. At the very base of the Triassic, abundant Ostracods (Crustacea) are systematically present, only in association with microbialites. Bacterial communities building the microbial mats should have served as an unlimited food supply. Photosynthetic cyanobacteria may also have locally provided oxygen to the supposedly anoxic environment: microbialites would have been refuges in the immediate aftermath of the EPE. Ostracods temporarily disappear together with microbialites during the Griesbachian.

Forel, Marie-Béatrice

2013-04-01

216

A new coil-stemmed camerate crinoid from the Permian of Eastern Australia  

Energy Technology Data Exchange (ETDEWEB)

A new dichocrinid camerate Neocamptrocrinus is proposed for a number of coiled stem species from the Permian of eastern Australia. As its name reflects, the genus closely resembles Camptrocrinus Wachsmuth and Springer from the Carboniferous of North America.

Willink, R.J.

1980-01-01

217

Late Paleozoic paleolatitude and paleogeography of the Midland basin, Texas  

Energy Technology Data Exchange (ETDEWEB)

During the Late Pennsylvanian through Early Permian, the Midland basin was located in the low latitudes. In the Desmoinesian (Strawn), the basin was astride the equator; during the Missourian (Canyon), the center of the basin had migrated northward so it was located at 1-2N latitude. In the Virgilian (Cisco), the basin center was located around 2-4N latitude, and by the Wolfcampian, it was positioned at around 4-6N latitude. From the Desmoinesian (312 Ma) through the Missourian (306 Ma), the relative motion of the basin was 63NE. Later during the Virgilian (298 Ma) to Wolfcampian (280 Ma), the direction of motion was 24NE. This change in motion reflects a major tectonic event, occurring between the Missourian and Virgilian, that greatly modifed the movement of the Laurentian (North American) plate. At that time, Laurentia had collided with Gondwana and become part of the supercontinent Pangea. Throughout the late Paleozoic, Laurentia was rotated so the Midland basin was oriented 43{degree} northeast from its current setting. Late Paleozoic paleogeography and paleolatitude controlled the direction of prevailing winds and ocean currents, thereby influencing the distribution of carbonate facies in the Midland basin. Present prevailing winds and ocean currents have been shown to have a major impact on modern carbonate sedimentation and facies distribution in Belize, the Bahamas and Turks, and Caicos. A clearer understanding of how late Paleozoic latitude and geography affected sedimentation helps explain and predict the distribution of carbonates throughout the Midland basin.

Walker, D.A. (Mobil Exploration and Producing U.S., Midland, TX (United States)); Golonka, J. (Mobil Exploration and Producing Services Inc., Dallas, TX (United States)); Reid, A.M.; Reid, S.T. (Consulting Geologist, Midland, TX (United States))

1992-04-01

218

The Siberian Traps and the end-Permian event: Geology, geochemistry and atmospheric modeling of gas release  

Science.gov (United States)

The Siberian Traps were emplaces through sedimentary basins covering the Siberian Craton, passing thick accumulations of carbonates and evaporites. Contact metamorphism of the sedimentary rocks around dolerite sills and dikes generated greenhouse gases and halocarbons to such an extent that the process could be responsible for both the end-Permian carbon isotope excursion and the mass extinction. The key processes are suggested to be 1) metamorphism of oil-saturated rock salt sequences (halocarbon production), 2) methane generation from metamorphism of organic-rich shales (methane production), and 3) decarbonation of dolostones (carbon dioxide production). We have analyzed the petrography and geochemistry (including carbon isotopes) of contact metamorphic carbonates from outcrops, and can document the devolatilization processes. In addition, we have explored the potential global warming effects of CO2 and CH4 emissions to the end-Permian atmosphere from the volatile generation. We have constrained the effect of century scale degassing events using the atmospheric lifetime of CH4 and CO2, the pre-event atmospheric composition in terms of methane and carbon-dioxide as well as H2S, the gas flux to the atmosphere, the IR absorption efficiency, the radiative forcing and the climate sensitivity. Assuming rapid emplacement of one single major sill intrusion into the Tunguska Basin, and 100 year gas release with 60% CH4 and 40% CO2, the global annual mean temperature could rise by 2-5°C (best estimate ~3.5°C). In contrast, degassing from subaerial lava flows with the same magma volume as a sill has one order of magnitude lower influence on the global climate, resulting in a warming of about 0.1°C. Per molecule CH4 is much more efficient in absorbing and re-emitting IR radiation than CO2, yielding a much stronger greenhouse effect in the Earth's atmosphere. Considering that the heat trapped in the atmosphere over a 100 year period resulting from an emission of CH4 is, under current conditions, about 25 times larger than from a similar mass of CO2, i.e. the Global Warming Potential (GWP) is ~25, the climate impact of a mixture containing 60% CH4 is strongly dominated by this compound. This effect increases with the amount of available H2S as it strongly influences the lifetime of CH4 in the atmosphere by reducing the oxidation potential. The method and geological model can be applied to other boundary events with LIPs, such as the Triassic-Jurassic boundary (~3.1°C), the Toarcian event (~2.9°C), and the Palaeocene-Eocene Thermal Maximum (~3.5°C).

Svensen, Henrik; Stordal, Frode; Roscher, Marco; Sokalska, Ewa; Planke, Sverre

2013-04-01

219

Acritarchs and tasmanites of the permo-carboniferous sediments of the Parana Basin; Acritarcos e tasmanites do permo-carbonifero da Bacia do Parana  

Energy Technology Data Exchange (ETDEWEB)

Reworked devonian palynomorphs are commonly found in Permo-Carboniferous sediments of the Parana Basin. The present study documents in situ Permo-Carboniferous acritarchs and tasmanites. The low abundance and taxonomic diversity of these palynomorphs are possibly related to shallow marine conditions. Three species, Comasphaeridium daemoni, Dictyotidium souzae and Micrhystridiium toigae, are described as new. Spores and pollen from the Carboniferous and Permian of the Parana Basin occurs associated to these acritarchs. (author)

Quadros, Luiz Padilha de. E-mail: luizquadros@hotmail.com

2002-06-01

220

Waterflood improvement in the Permian Basin: Impact of in-situ-stress evaluations  

Energy Technology Data Exchange (ETDEWEB)

The authors evaluated in-situ-stress magnitudes and directions to support waterflood improvement programs in McElroy field and North Westbrook Unit. In-situ-stress and hydraulic-fracture directions coincided with directional floodwater effects. This information contributed to successful waterflood realignment programs.

Nolen-Hoeksema, R.C.; Avasthi, J.M. (Chevron Petroleum Technology Co., Houston, TX (United States)); Pape, W.C. (West Australian Petroleum Pty. Ltd., Perth (Australia)); El Rabaa, A.W. (Mobil E and P Technical Center, Dallas, TX (United States))

1994-11-01

 
 
 
 
221

Declining Petroleum Production and the Effect Upon Communities in New Mexico's Permian Basin  

Science.gov (United States)

The petroleum industry, a vital component of New Mexico's economy, is in a gradual decline. As petroleum production is primarily focused in the southeastern corner of the state, this decline phenomenon is particularly relevant to area residents. The problem addressed in this study was that little information is available regarding the lived experiences of business and community leaders concerning this phenomenon, particularly in terms of future economic sustainability. The purpose of this qualitative phenomenological study was to interview a purposive sample of business and community leaders regarding their lived experiences and perceptions relating to the economic sustainability of the region. Research questions asked about the general awareness of the decline of oil production---data collected from federal and state databases---and potential options for alternative economic development. Coded data were analyzed and themes and patterns were identified. Findings included a general lack of awareness of area residents regarding a decline of production, assumed economic stability, and resistance to change based on a lack of incentive. Included in the findings were potential options for strategic economic diversification. Recommendations included a campaign to promote awareness of the decline of oil, provide incentives for change, and economic diversification as method of moving the local economy away from dependence upon the petroleum industry. Implications for positive social change were that the affected region can use the findings to identify sustainable alternative industries to support the communities into the future.

Tipton, Ryan D.

222

Oxidoreduction processus in a uranium deposit (Aumance - Cerilly Permian basin, Allier (France))  

International Nuclear Information System (INIS)

[en] Stratigraphic and tectonic data are briefly reviewed. Then a method giving the oxidoreducing properties of elements and using the chemical oxygen demand is exposed. The study of secondary textures shows the effects of the oxidoreducing process. Three pyrite textures were identified at Cerilly by petrographic observations. They are always bound to a secondary enrichment in uranium and they can be used as an exploration guide. Application of factor analysis confirms the studied phenomenon

1982-01-01

223

Late Permian global coal hiatus linked to {sup 13}C depleted CO{sub 2} flux into the atmosphere during the final consolidation of Pangea  

Energy Technology Data Exchange (ETDEWEB)

At a time when all continents were finally arrayed in their Pangea supercontinental configuration (250 {+-} 50 Ma), Earth`s stratigraphy records a global and very abrupt coal discontinuity. From the Tartarian stage of the Late Permian to the Middle Triassic, reduced coal productivity and/or preservation overlaps with a period of anomalous oceanic and atmospheric decrease in {sup 13}C, as recorded in marine carbonates and organic matter, and terrestrial plant and animal fossils from the Northern and Southern hemispheres. During the same short period, the peripheral margin of the entire supercontinent Pangea, except for the southern shores of Tethys, was effectively under compressive stress. This unique tectonic state caused deformation and uplift of coal-bearing foreland basins and oxidation of Pangea`s vast peat deposits. The latter resulted in a rapid, massive {sup 13}C-depleted CO{sub 2} flux into the atmosphere, which in turn may have forced global warming.

Faure, K.; Dewit, M.J.; Willis, J.P. [University of Cape Town, Rondesbosch (South Africa). Dept. of Geological sciences

1995-06-01

224

Evolution of the Early Permian volcanic-plutonic complex in the western part of the Permian Gobi-Altay Rift (Khar Argalant Mts., SW Mongolia)  

Directory of Open Access Journals (Sweden)

Full Text Available The Lower Permian volcano-sedimentary complexes of the Khar Argalant and Delger Khangay formations in the Khar Argalant Mts. in south-western Mongolia are products of postorogenic within-plate magmatic activity. They consist of terrestrial lavas and pyroclastic flows with local intercalations of clastic sedimentary rocks. Vascular plants in volcano-clastic layers correspond to typical Lower to Middle Permian terrestrial associations formed under dry to intermediate conditions of temperate to colder climatic zones. The plant communities of all three formations show affinities to the Siberia (Angara) “Cordaitean taiga”. Relationships of volcanic rocks suggest simultaneous eruptions of mafic (basalt to trachyandesite) and felsic (trachyte to rhyolite) lavas. The rocks of both formations have similar major- and trace-element contents as well as volcanological character. The granite of the Shar Oroy Massif, with zircon concordia age of 285 ± 1 Ma, was roughly contemporaneous with the volcanic rocks of the Delger Khangay Fm. The Early/Late Permian clastic sedimentary rocks of the Butnaa Khudag Fm. in the hanging wall of the Delger Khangay Fm. postdated the terrestrial volcanic events. Geochemical and structural characteristics suggest that the Shar Oroy Massif and the surrounding Permian volcanic suite represent an eroded, shallow-level plutonic centre and its eruptive cover, which evolved during a crustal extension.

Buriánek D; Hanžl P; Budil P; Gerdes A

2012-01-01

225

Oil and gas potential of Amazon Paleozoic basins  

Energy Technology Data Exchange (ETDEWEB)

The Paleozoic basins, covering an area of about 800,000 km/sup 2/ (309,000 mi/sup 2/) in the Amazon region, are elongate symmetrical intracratonic synclines filled with as much as 4000 m (13,000 ft) of sediments, separated by basement uplifts or major arches and located in continental interior areas (as are the United State Illinois, Michigan, and Williston basins). Tectonics affected differentially these basins during the Triassic Jurassic and Early Cretaceous, associated with widespread basic volcanism. 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 m/sup 3/ (4.237 tcf) and exploration follows the productive trend toward the west-southwest. Potential reservoir rocks in Middle and Lower Amazon basis are Permian Monte Alegre and Devonian Oriximina sandstones. Major source rocks in all three basins are Devonian Barreirinha black, shales. 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.

Mosmann, R.; Falkenhein, F.U.H.; Goncalves, A.; Nepomuceno, F.

1984-09-01

226

Salt tectonics in the northeastern Nordkapp Basin, southwestern Barents Sea  

Energy Technology Data Exchange (ETDEWEB)

Salt structures in the northeastern Nordkapp subbasin are interpreted on reflection seismic profiles. Thickness variations indicate localized accumulation of the mother salt in Late Carboniferous-Early Permian time. Rapid sedimentation in the Early Triassic accompanied rise of salt into asymmetric salt pillows during regional extension. These pillows domed the prekinematic Permian sediments and became diapiric during the late Early-Middle Triassic, perhaps as a result of thin-skinned normal faulting decoupled by the salt from old basements faults reactivated by thick-skinned regional (northwest-southeast) extension. Variations in size, maturity, and evolution history of individual salt structures can be attributed to local differences in thickness of the initial salt layer and its burial history. Salt structures form three rows concentric to the basin margins and cover {approximately}20% of the basin area. Some salt stocks appear to overlie basement faults. Asymmetric primary, secondary, and in places tertiary, peripheral sinks indicate that salt was withdrawn mainly from the basin side of most diapirs throughout Triassic downbuilding.

Koyi, H.; Talbot, C.J. [Hans Ramberg Tectonic Lab., Uppsala (Sweden); Torudbakken, B.O. [Saga Petroleum a.s., Sandvika (Norway)

1996-12-31

227

Simulated warm polar currents during the middle Permian  

Energy Technology Data Exchange (ETDEWEB)

During Permian Stage 6 (Wordian, Kazanian) the Pangaean supercontinent was surrounded by a superocean - Panthalassa. An ocean general circulation model has been coupled to an atmospheric energy balance model to simulate the sensitivity of the Wordian climate ({proportional_to}265 million years ago) to changes in greenhouse gas concentrations, high latitude geography, and Earth orbital configurations. The model shows a high sensitivity of the ocean circulation to changes in the greenhouse gas forcing, ranging from a forceful southern circulation at low CO{sub 2} concentration (present level) to a more symmetric circulation cell with deep water formation in both hemispheres at high CO{sub 2} concentration (8 x present level). The simulated climate with 4 x present level CO{sub 2} concentration agrees generally well with climate-sensitive sediments and phytogeographic patterns. In this experiment, the model simulates strong subtropical gyres with similarities to the modern South Pacific circulation and moderate surface temperatures on the southern continent Gondwana, resulting from a strong poleward heat transport in the ocean. An even more moderate climate can be generated if high latitude land is removed so that ocean currents can penetrate into the polar regions or if orbital configurations favor high summer insolation over Gondwana. (orig.)

Winguth, A.M.E.; Kutzbach, J.E. [Wisconsin Univ., Madison, WI (USA). Center for Climatic Research; Heinze, C.; Maier-Reimer, E.; Mikolajewicz, U. [Max-Planck-Institut fuer Meteorologie, Hamburg (Germany); Rowley, D.; Rees, A.; Ziegler, A.M. [Chicago Univ., IL (United States). Dept. of Geophysical Sciences

2001-05-01

228

Time-calibrated Milankovitch cycles for the late Permian.  

UK PubMed Central (United Kingdom)

An important innovation in the geosciences is the astronomical time scale. The astronomical time scale is based on the Milankovitch-forced stratigraphy that has been calibrated to astronomical models of paleoclimate forcing; it is defined for much of Cenozoic-Mesozoic. For the Palaeozoic era, however, astronomical forcing has not been widely explored because of lack of high-precision geochronology or astronomical modelling. Here we report Milankovitch cycles from late Permian (Lopingian) strata at Meishan and Shangsi, South China, time calibrated by recent high-precision U-Pb dating. The evidence extends empirical knowledge of Earth's astronomical parameters before 250 million years ago. Observed obliquity and precession terms support a 22-h length-of-day. The reconstructed astronomical time scale indicates a 7.793-million year duration for the Lopingian epoch, when strong 405-kyr cycles constrain astronomical modelling. This is the first significant advance in defining the Palaeozoic astronomical time scale, anchored to absolute time, bridging the Palaeozoic-Mesozoic transition.

Wu H; Zhang S; Hinnov LA; Jiang G; Feng Q; Li H; Yang T

2013-09-01

229

Complete tylosis formation in a latest Permian conifer stem.  

UK PubMed Central (United Kingdom)

BACKGROUND AND AIMS: Our knowledge of tylosis formation is mainly based on observations of extant plants; however, its developmental and functional significance are less well understood in fossil plants. This study, for the first time, describes a complete tylosis formation in a fossil woody conifer and discusses its ecophysiological implications. METHODS: The permineralized stem of Shenoxylon mirabile was collected from the upper Permian (Changhsingian) Sunjiagou Formation of Shitanjing coalfield, northern China. Samples from different portions of the stem were prepared by using the standard thin-sectioning technique and studied in transmitted light. KEY RESULTS: The outgrowth of ray parenchyma cells protruded into adjacent tracheids through pits initially forming small pyriform or balloon-shaped structures, which became globular or slightly elongated when they reached their maximum size. The tracheid luminae were gradually occluded by densely spaced tyloses. The host tracheids are arranged in distinct concentric zones representing different growth phases of tylosis formation within a single growth ring. CONCLUSIONS: The extensive development of tyloses from the innermost heartwood (metaxylem) tracheids to the outermost sapwood tracheids suggests that the plant was highly vulnerable and reacted strongly to environmental stress. Based on the evidence available, the tyloses were probably not produced in response to wound reaction or pathogenic infection, since evidence of wood traumatic events or fungal invasion are not recognizable. Rather, they may represent an ecophysiological response to the constant environmental stimuli.

Feng Z; Wang J; Rößler R; Kerp H; Wei HB

2013-06-01

230

Petrographic composition, sedimentary structures and palaeocurrent analysis in Northern Gondwana: The Lower Permian Warchha Sandstone of the Salt Range, Pakistan  

Science.gov (United States)

The Warchha Sandstone is a Lower Permian fluvial succession present in both outcrop and subsurface throughout the Salt Range and the Potwar Basin of Pakistan that originally accumulated in a palaeogeographic setting adjacent to the northern margin of Gondwana. Sandstone beds are feldspatho-quartzose, including dominantly monocrystalline quartz, more K-feldspar than plagioclase, and mainly plutonic and low-grade metamorphic rock fragments. Twenty-eight fining-upward cycles, composed of conglomerate, sandstone, siltstone and claystone are identified. A varied range of sedimentary structures is recognised, including different forms of cross-bedding, ripple marks, flute casts, load casts, desiccation cracks, rain prints, cone-in-cone structures, and a variety of types of concretions and bioturbation. The occurrence and abundance of these structures varies in a systematic manner throughout the vertical thickness of the succession. Sedimentary structures, palaeocurrent data and lithofacies arrangement indicate deposition in a high-sinuosity meandering river system. Detailed palaeocurrent analysis reveals a broad unimodal palaeoflow within each cycle with dominant flow direction having been towards the north-northwest, but with significant changes in local bedform migration direction between each cycle. The northward flowing river transported sediments from the Aravalli and Malani Ranges that lay to the south to the Salt Range, northwards to the Tethyan proto-ocean in the north.

Ghazi, Shahid; Mountney, Nigel P.

2012-10-01

231

Organic petrology, thermal maturity, geology, and petroleum source rock potential of Lower Permian coal, Karoo supersystem, Zambia  

Energy Technology Data Exchange (ETDEWEB)

This paper reports on data concerning organic petrology and thermal maturity of Lower Karoo coal measures (Lower Permian) which are of considerable importance in determining the hydrocarbon potential of sediments in the rift-valley and half-graben complexes of the Luangwa and Zambezi valleys of eastern and southern Zambia, respectively, and in the extensive sedimentary basin developed on relatively stable Precambrian basement in western Zambia, a total area in excess of 3000 km{sup 2}. Samples from seven outcrop and subsurface localities situated in the northeast (northern Luangwa Valley), east (mid-Luangwa Valley), south (mid-Zambezi Valley), and the Western Province of Zambia were studied. The coal measures are from 9 to 280 m thick, but individual coal seams are generally less than 6 m. The coal macerals contain an average of 60% vitrinite and 9% liptinite, enough to have potential to generate hydrocarbon. A few samples contain twice this amount of liptinite. Reflected-light microscopy and the thermal alteration index of spores were used to determine the thermal maturity. The organic matter in samples studied is within the oil generation zone (thermal alteration index 2{minus} to 2+; %R{sub 0} max = 0.5-0.9). The petrological and palynological data indicate that the organic matter consists of Types II (generally approximately 25% in carbonaceous shale samples), III, and IV, indicating source rock potential. Late Karoo ( ) and post-Karoo fault blocks with differential vertical displacements may have produced structural traps suitable for oil and gas accumulation.

Utting, J. (Institute of Sedimentary and Petroleum Geology, Calgary, AB (Canada)); Wielens, H. (Unocal Canada Exploration Ltd., 150 6th Av. SW, Calgary, Alberta (CA))

1992-10-01

232

Raining lead around 250mya a smoking gun for an Australian impact origin of the Permian Extinction  

CERN Multimedia

Recent documentation of extreme atmospheric sulfur and methane contents at the time of the vast Permo-Triassic (P-T) extinction makes it possible to interpret an observation that has lain unnoticed in the geological literature for 40 years. This is the finding of microscopic metallic lead tear drops in the fluvial strata of the early Triassic sandstones that overlie Permian coal beds and other sedimentary deposits in the Sydney basin of Australia. Elemental lead is almost unknown in nature, so its occurrence in these graphite-loaded sandstones is a provocative finding. While climate change and vulcanism could explain the carbon and sulfur anomalies, the only way to account for metallic lead aerodynamic droplets is by massive impact and vaporization of lead mineral-containing formations. Since lead occurs geologically as the sulfide and since lead is an easily reduced element, its occurrence in conjunction with sulfur and carbon count anomalies suggests a bolide impact on carbon-loaded strata in a sulfide mine...

Standard, J C

2003-01-01

233

Permian plants from the Chutani Formation (Titicaca Group, Northern Altiplano of Bolivia): I. Genera Pecopteris and Asterotheca  

Directory of Open Access Journals (Sweden)

Full Text Available Fossil plants belonging to the morphogenera Glossopteris, Pecopteris and Asterotheca were collected from the upper part of the Chutani Formation (Titicaca Group), near the town of San Pablo de Tiquina, on the southeastern shore of Lake Titicaca (northern Altiplano, Bolivia). Here we report the analysis of fern-type foliage found at this location. Three species of pecopterid fronds are identified: Pecopteris dolianitii Rohn and Rösler, P. cf. P. cadeadensis Rohn and Rösler, and P. cf. P. pedrasica Read. All these species are typically found in Permian deposits of the Paraná Basin in southern Brazil. Despite the poor preservation of the material, a fertile specimen could be studied and was determined as Asterotheca sp. The paleoenvironmental and paleoecological implications of this new find are briefly analyzed.Plantas fósseis, pertencentes aos morfo-gêneros Glossopteris, Pecopteris e Asterotheca, foram coletadas na porção superior da seção aflorante da Formação Chutani, próxima ao povoado de San Pablo de Tiquina, sudeste do lago Titicaca (Altiplano norte, Bolívia). Este trabalho analisa folhagens do tipo feto encontradas neste sítio. Entre os espécimes estéreis, três espécies de frondes pecopterídeas foram identificadas: Pecopteris dolianiti, P. cf. cadeadensis e P. cf. pedrasica. Todas essas espécies eram até agora restritas aos depósitos permianos da Bacia do Paraná. A despeito do estado de preservação ruim do material, um espécime fértil pôde ser determinado como pertencente ao gênero Asterotheca. Implicações paleoambientais e paleoecológicas deste novo achado são brevemente analisadas.

Carlos E. L. Vieira; Roberto Iannuzzi; Margot Guerra-Sommer; Enrique Díaz-Matrínez; George W. Grader

2004-01-01

234

A new captorhinid reptile, Gansurhinus qingtoushanensis, gen. et sp. nov., from the Permian of China.  

UK PubMed Central (United Kingdom)

Captorhinids, a clade of Paleozoic reptiles, are represented by a rich fossil record that extends from the Late Carboniferous into the Late Permian. Representatives of this clade dispersed from the equatorial regions of Laurasia into the temperate regions of Pangea during the Middle and Late Permian. This rich fossil record shows that there was an evolutionary trend from faunivorous to omnivorous and herbivorous feeding habits within this clade. The discovery of well-preserved captorhinid materials in the Middle Permian of China allows us to determine that the new taxon, Gansurhinus qingtoushanensis, gen. et sp. nov, is a member of Moradisaurinae, a clade of captorhinids with multiple tooth rows arranged in parallel. The presence of this moradisaurine in the Middle Permian of south central Asia leads us to suggest that paleogeographic changes during the Permian, with part of what is today China becoming a large peninsula of Pangea, allowed these early reptiles as well as other terrestrial vertebrates to extend their geographic ranges to this region of the Late Paleozoic supercontinent.

Reisz RR; Liu J; Li JL; Müller J

2011-05-01

235

A new captorhinid reptile, Gansurhinus qingtoushanensis, gen. et sp. nov., from the Permian of China  

Science.gov (United States)

Captorhinids, a clade of Paleozoic reptiles, are represented by a rich fossil record that extends from the Late Carboniferous into the Late Permian. Representatives of this clade dispersed from the equatorial regions of Laurasia into the temperate regions of Pangea during the Middle and Late Permian. This rich fossil record shows that there was an evolutionary trend from faunivorous to omnivorous and herbivorous feeding habits within this clade. The discovery of well-preserved captorhinid materials in the Middle Permian of China allows us to determine that the new taxon, Gansurhinus qingtoushanensis, gen. et sp. nov, is a member of Moradisaurinae, a clade of captorhinids with multiple tooth rows arranged in parallel. The presence of this moradisaurine in the Middle Permian of south central Asia leads us to suggest that paleogeographic changes during the Permian, with part of what is today China becoming a large peninsula of Pangea, allowed these early reptiles as well as other terrestrial vertebrates to extend their geographic ranges to this region of the Late Paleozoic supercontinent.

Reisz, Robert R.; Liu, Jun; Li, Jin-Ling; Müller, Johannes

2011-05-01

236

Palaeomagnetic results from the Early Permian Copacabana Group, southern Peru: Implication for Pangaea palaeogeography  

Science.gov (United States)

Samples collected from folded carbonate rocks of the Early Permian Copacabana Group exposed in the Peruvian Subandean Zone have been subjected to detailed palaeomagnetic analysis. Thermal demagnetisation of most samples yield stable high unblocking temperature directions dominantly carried by titanomagnetite minerals. This remanence, identified in 32 samples (43 specimens), is exclusively of reverse polarity consistent with the Permian Carboniferous Reversal Superchron (PCRS). The overall directions pass the fold test at the 99% confidence level and are considered as being a pre-folding remanence acquired in Early Permian times. The Copacabana Group yields an overall mean direction of D = 166°, I = +49° (?95 = 4.5°, k = 131.5, N = 9 sites) in stratigraphic coordinates and a corresponding palaeosouth pole position situated at ? = 68°S, ? = 321°E (A95 = 5.2°, K = 100). Combining this pole with the coeval high quality data from South America, Africa and Australia results in a mean pole for Gondwana situated at ? = 34.4°S, ? = 065.6°E (A95 = 4.9°, K = 73.6, N = 13 studies) in African coordinates. This pole position supports a Pangaea B palaeogeography in Early Permian times. In contrast, the combined pole for Gondwana diverges from the coeval Laurasian mean pole when assuming the Pangaea A-type configuration. Poor quality of the Gondwana dataset and inclination shallowing in sediments seem to play no role in the misfit between the Permian Triassic poles from Gondwana and Laurasia in Pangaea A reconstruction.

Rakotosolofo, N. A.; Tait, J. A.; Carlotto, V.; Cárdenas, J.

2006-02-01

237

Stratigraphy of Upper Permian and Lower Triassic Strata of the Žiri Area (Slovenia)  

Directory of Open Access Journals (Sweden)

Full Text Available The paper deals with the stratigraphy of Late Permian and Early Triassic strata of the Luka? section in the Žiri area of western Slovenia. This is the only section presently known in the External Dinarides where the Permian-Triassic boundary is defined following international criteria based on the first appearance of the conodont Hindeodus parvus. The following lithostratigraphic units have been formalized: the Bellerophon Limestone and Evaporite-dolomite Members of the Bellerophon Formation and the Luka~ Formation with the three members,the Transitional Beds, Streaky Limestone and Carbonate-clastic Member. The paper presents the results of micropaleontologicalstudy based on foraminifers and conodonts as well as petrographic and sedimentologic research results. The investigation of conodont assemblages enabled the conodont biozonation of the Permian-Triassic interval of the studied Luka? section.

Tea Kolar-Jurkovšek; Bogdan Jurkovšek; Dunja Aljinovi?; Galina P. Nestell

2011-01-01

238

Upper Permian ostracode assemblage from the Jadar Block (Vardar zone, NW Serbia)  

Directory of Open Access Journals (Sweden)

Full Text Available Ostracodes from the Changhsingian (latest Permian age) in the uppermost part of the “Bituminous Limestone” Formation of the Komiri? Section in NW Serbia (Jadar Block, Vardar Zone) are described and illustrated. Three new species of ostracodes are introduced: Basslerella jadarensis n. sp., Acratia serbianella n. sp., and Knoxiella vardarensis n. sp. The ostracode assemblage, together with conodonts and foraminifers, is the first record of the youngest Late Permian age microfaunas from Serbia and from the central part of the Balkan Peninsula.

Crasquin Sylvie; Sudar Milan N.; Jovanovi? Divna; Kolar-Jurkovšek Tea

2010-01-01

239

Stratigraphy and depositional history of the Upper Palaeozoic and Triassic sediments in the Wandel Sea Basin, central and eastern North Greenland  

Energy Technology Data Exchange (ETDEWEB)

A lithostratigraphic scheme is erected for the Lower Carboniferous to Triassic sediments of the Wandel Sea Basin, from Lockwood {phi} in the west to Holm Land in the east. The scheme is based on the subdivision into the Upper Carboniferous - Lower Permian Mallemuk Mountain Group and the Upper Permian - Triassic Trolle Land Group. In addition the Upper Carboniferous Sortebakker Formation and the Upper Permian Kap Kraka Formation are defined. Three formations and four members are included int he Mallemuk Mountain Group. Lithostratigraphic units include: Kap Jungerson Formation (new) composed of interbedded limestones, sandstones and shales with minor gypsum - early Moscovian; Foldedal Formation compsed of interbedded limestones and sandstones - late Moscovian to late Gzhelian; Kim Fjelde Formation composed of well bedded limestones - late Gzhelian to Kungurian. The Trolle Land Group includes three formations: Midnatfjeld Formation composed of dark shales, sandstones and limestones - Late Permian; Parish Bjerg Formation composed of a basal conglomeratic sandstone overlain by shales and sandstones - Early Triassic (Scythian); Dunken Formation composed of dark shales and sandstones - Triassic (Scythian-Anisian). The Sortebakker Formation (new) is composed of interbedded sandstones, shales and minor coal of floodplain origin. The age is Early Carboniferous. The Kap Kraka formation (new) includes poorly known hematitic sandstone, conglomerates and shales of Lat Permian age. (author) 34 refs.

Stemmerik, L. (Geological Survey of Greenland, Copenhagen (DK)); Haakansson, E. (Institute of Historical Geology and Palaeontology, Copenhagen (DK))

1989-01-01

240

Sequences and stratigraphic hierarchy of the Parana Basin (Ordovician Cretaceous), Southern Brazil  

Energy Technology Data Exchange (ETDEWEB)

The Parana Basin, a vast sedimentation area during Paleozoic and Mesozoic times, holds a stratigraphic record ranging in age from late Ordovician to late Cretaceous and comprising six supersequences or unconformity-bounded units (Milani, 1997): Rio Ivai (Ordovician-Silurian), Parana (Devonian), Gondwana I (Carboniferous-early Triassic), Gondwana II (middle-late triassic), Gondwana III (late Jurassic-early Cretaceous), and Bauru (late Cretaceous). Three of them coincide with major Paleozoic transgressive-regressive cycles, and the others are Mesozoic continental sedimentary packages with associated igneous rocks. These supersequences are the remnant record of successive phases of sediment accumulation alternating with times of erosion. The evolution of each supersequence was constrained by a particular tectonic and climatic setting. The Rio Ivai supersequence is closely associated with basin inception and its geometry suggests that deposition was to some extent controlled by normal faulting. The Parana supersequence deposited during a time of widespread marine flooding over the cratonic area of southwester Gondwana. From the deposition of the Gondwana I supersequence onward tru intracration conditions were established. Sharing Gondwana's dessication trend the Parana Basin sedimentation history culminated with extensive desertic conditions during the Jurassic. The Lower Cretaceous Serra Geral continental flood basalts are related to the initial moments of South Atlantic rifting and the upper Cretaceous Bauru continental cover ended the history of the basin. The hydrocarbon potential of the Parana Basin is related to two well defined source beds: the Devonian shales (Ponta Grossa Formation) and the upper Permian bituminous shales and limestones (Irati Formation). Sandy reservoirs can be found in the lower Devonian Furnas Formation, in the upper Carboniferous/lower Permian Iatarare Group and in the lower Permian Rio Bonito Formation. The role of intrusive bodies in the maturation of source rocks and in the trapping of hydrocarbons seems to be crucial and deserves more investigation. (author)

Milani, E.J.; Araujo, L.M.; Cupertino, J.A. [PETROBRAS, Rio de Janeiro, RJ (Brazil). Exploracao e Producao; Faccini, U.F. [Universidade do Vale do Rio dos Sinos (UNISINOS), Sao Leopoldo, RS (Brazil); Scherer, C.M. [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Inst. de Geociencias

1998-07-01

 
 
 
 
241

Direct shear testing on rock core samples from Mansfield No. 1 (PD-4) well, Palo Duro Basin, Texas: unanalyzed data  

Energy Technology Data Exchange (ETDEWEB)

This report contains the direct shear strength testing procedure and testing results for rock core samples from the Mansfield No. 1 Well in the Permian Basin. These attachments are included: shear surface photographs, shear surface profiles, shear stress and vertical displacement versus horizontal displacement, and stress ratio and vertical displacement versus horizontal displacement. These data are preliminary. They have been neither analyzed nor evaluated. 2 figures.

1984-08-01

242

Direct shear testing on rock core samples from Mansfield No. 1 (PD-4) well, Palo Duro Basin, Texas: unanalyzed data  

International Nuclear Information System (INIS)

[en] This report contains the direct shear strength testing procedure and testing results for rock core samples from the Mansfield No. 1 Well in the Permian Basin. These attachments are included: shear surface photographs, shear surface profiles, shear stress and vertical displacement versus horizontal displacement, and stress ratio and vertical displacement versus horizontal displacement. These data are preliminary. They have been neither analyzed nor evaluated. 2 figures

1984-01-01

243

Records of Late Permian surface temperatures in continental Gondwana in isotope geochemistry of upper Permian early diagenetic calcite concretions  

Energy Technology Data Exchange (ETDEWEB)

We present geochemical and isotopic evidence of paleotemperatures from freshwater continental deposits from 55{degrees}S in interior southern Gondwana. Lacustrine shales host spheroidal concretions with abundant septarian cracks. Cement carbonate varies from 65% at the centre to 15% at the edges. Cistraccide remains are preserved. Septarian calcite occurs in dull and bright bands, with three distinct generations of vein-fills. Early-formed cement both in concretions and septarian veins is magnesium-rich whereas, later-formed carbonates are pure calcite. Carbon- and oxygen-isotope ratios (PDB) are: host shales, {delta}{sup 13}C= -4.36 to o.77{per_thousand}, {delta}{sup 18}O= -12.73 to -17.12{per_thousand}; concretion cements, {delta}{sup 13}C=+0.26 to {delta}{sup 18}O= -9.34{per_thousand}; and vein-fills, {delta}{sup 13}C= -7.05 to +1.09{per_thousand}, {delta}{sup 18}O= -8.28 to -18.24{per_thousand}. 13C and 18O ratios are depleted from the center of concretions to the periphery, as well as from the centre of veins to the tip. Near-surface cementation is suggested by textural evidence. {delta}18O in the range of -12.636{per_thousand} to -8.989 SMOW is calculated for the meteoric palaeowaters, from which average annual surface temperatures of 5-8{degrees}C are inferred. {delta}18O of early-formed cements also yields a mean annual surface temperature of 2-6{degrees}C. Based on continentality and palaeolatitudes of northern Malawi during the Late Permian, we propose that mean annual surface palaeotemperatures may have been as high as 10{degrees}C, similar to those found in modern continental temperate climates.

Yeman, E. [Univ. Pennsylvania, Philadelphia, PA (United States); Kelts, K. [Univ. of Minnesota, Minneapolis, MN (United States)

1996-12-31

244

Sedimentology and cyclicity in the Lower Permian De Chelly Sandstone on the Defiance Plateau: eastern Arizona  

Science.gov (United States)

The Lower Permian (Leonardian) De Chelly Sandstone crops out along a north-south trend on the Defiance Plateau of eastern Arizona. It is divided into lower and upper members separated by a tongue of the Supai Formation that pinches out to the north. Stratigraphy, and lateral and vertical facies relations within the lower and upper members, are discussed. -from Author

Stanesco, J. D.

1991-01-01

245

Large Perturbations of the Carbon Cycle During Recovery from the End-Permian Extinction  

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High-resolution carbon isotope measurements of multiple stratigraphic sections in south China demonstrate that the pronounced carbon isotopic excursion at the Permian-Triassic boundary was not an isolated event but the first in a series of large fluctuations that continued throughout the Early Trias...

Schrag, Daniel; Knoll, Andrew; Orchard, Michael J.; Wei, Jiayong; Lehrmann, Daniel J.; Payne, Jonathan L.

246

Controls on body size during the Late Permian mass extinction event.  

UK PubMed Central (United Kingdom)

This study examines the morphological responses of Late Permian brachiopods to environmental changes. Quantitative analysis of body size data from Permian-Triassic brachiopods has demonstrated significant, directional changes in body size before, during and after the Late Permian mass extinction event. Brachiopod size significantly reduced before and during the extinction interval, increased for a short time in more extinction-resistant taxa in the latter stages of extinction and then dramatically reduced again across the Permian/Triassic boundary. Relative abundances of trace elements and acritarchs demonstrate that the body size reductions which happened before, during and after extinction were driven by primary productivity collapse, whereas declining oxygen levels had less effect. An episode of size increase in two of the more extinction-resistant brachiopod species is unrelated to environmental change and possibly was the result of reduced interspecific competition for resources following the extinction of competitors. Based on the results of this study, predictions can be made for the possible responses of modern benthos to present-day environmental changes.

He WH; Twitchett RJ; Zhang Y; Shi GR; Feng QL; Yu JX; Wu SB; Peng XF

2010-12-01

247

Controls on body size during the Late Permian mass extinction event.  

Science.gov (United States)

This study examines the morphological responses of Late Permian brachiopods to environmental changes. Quantitative analysis of body size data from Permian-Triassic brachiopods has demonstrated significant, directional changes in body size before, during and after the Late Permian mass extinction event. Brachiopod size significantly reduced before and during the extinction interval, increased for a short time in more extinction-resistant taxa in the latter stages of extinction and then dramatically reduced again across the Permian/Triassic boundary. Relative abundances of trace elements and acritarchs demonstrate that the body size reductions which happened before, during and after extinction were driven by primary productivity collapse, whereas declining oxygen levels had less effect. An episode of size increase in two of the more extinction-resistant brachiopod species is unrelated to environmental change and possibly was the result of reduced interspecific competition for resources following the extinction of competitors. Based on the results of this study, predictions can be made for the possible responses of modern benthos to present-day environmental changes. PMID:20550584

He, W-H; Twitchett, R J; Zhang, Y; Shi, G R; Feng, Q-L; Yu, J-X; Wu, S-B; Peng, X-F

2010-12-01

248

CHEMICAL SIGNATURE OF TWO PERMIAN VOLCANIC ASH DEPOSITS WITHIN A BENTONITE BED FROM MELO, URUGUAY  

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A Permian bentonite deposit at Melo, Uruguay is composed of a calcite-cemented sandstone containing clay pseudomorphs of glass shards (0-0.50 m) overlying a pink massive clay deposit (0.50-2.10m). The massive bed is composed of two layers containing quartz and smectite or pure smectite respectively....

Calarge, L.; Meunier, A.; Lanson, B.; L. Formoso, M.

249

Unique organic remains from an upper Permian coal bearing sequence in the Talcher Coalfield, Orissa, India  

Energy Technology Data Exchange (ETDEWEB)

The playnological assemblage of coal bearing upper Permian sequence of Talcher Coalfield registers presence of some peculiar organic remains. These are described as Orissiella gen. nov., which is characterized by a vesicle with collar-like structure at the oral end, spines and or corrugations on the body. The affinity and palaeoecological significance of Orissiella is also discussed. 12 refs., 4 figs., 2 plates.

Tripathi, A. [Birbal Sahni Institute of Palaeobotany, Lucknow (India)

2004-07-01

250

Sedimentology of a Permian playa lake: the Boda Claystone Formation, Hungary  

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The Upper Permian Boda Claystone Formation (BCF) in SW Hungary has been previously been identified as a saline lake deposit. A country-wide screening found this 800–1000 m thick succession the most suitable for the disposal of high-level radioactive waste in Hungary, and research into this formation...

Konrád, Gyula; Sebe, Krisztina; Halász, Amadé; Babinszki, Edit

251

Absence of Extraterrestrial 3He in Permian–Triassic Age Sedimentary Rocks  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Helium concentration and isotopic composition were measured in a suite of samples across the Permian–Triassic boundary at Opal Creek, Canada, to determine whether high extraterrestrial helium concentrations are associated with a possible extinction-inducing impact event at this time. No extraterrest...

Garrison, G.; Ward, P.; Farley, K. A.; Mukhopadhyay, Sujoy

252

Ostracods (Crustacea) associated with microbialites across the Permian-Triassic boundary in Dajiang (Guizhou Province, South China)  

Directory of Open Access Journals (Sweden)

Full Text Available 26 samples were processed for a taxonomic study of ostracods from the Upper Permian (Changhsingian) - Lower Triassic (Griesbachian) interval of the Dajiang section, Guizhou Province, South China. 112 species belonging to 27 genera are recognized. Five new species are described: Acratia candyae sp. nov, Bairdia adelineae sp. nov., Bairdia? huberti sp. nov., Bairdia jeromei sp. nov., Orthobairdia jeanlouisi sp. nov. The unexpected survival faunas associated with microbial formations in the aftermath of the end-Permian extinction are documented for the first time. Ostracod biodiversity variations and palaeo-environmental modifications associated with microbial growth through the Permian-Triassic boundary (PTB) are discussed.

Marie-Beatrice FOREL

2012-01-01

253

Stratigraphic and palaeoenvironmental framework of the Early Permian sequence in the Salt Range, Pakistan  

Science.gov (United States)

The Early Permian Gondwana regime succession of the Nilawahan Group is exposed only in the Salt Range of Pakistan. After a prolonged episode of non-deposition that spanned much of the Palaeozoic, the 350 m thick predominantly clastic sequence of the Nilawahan Group records a late glacial and post-glacial episode in which a range of glacio-fluvial, marine and fluvial environments evolved and accumulated. The Early Permian succession of the Salt Range has been classified into four formations, which together indicates a changing climatic regime during the Early Permian in the Salt Range region. The lower-most, Tobra Formation unconformably overlies a Cambrian sequence and is composed of tillite, diamictite and fresh water facies, which contain a floral assemblage ( Gangamopteris and Glossopteris) that confirms an Asselian age. The Tobra Formation is overlain by marginal marine deposits of the Dandot Formation (Sakmarian), which contain an abundant brachiopods assemblage ( Eurydesma and Conularia). Accumulation of the Dandot Formation was terminated by a regional sea-level fall and a change to the deposition of the fluvial deposits of the Warchha Sandstone (Artinskian). The Warchha Sandstone was deposited by high sinuosity meandering, avulsion prone river with well developed floodplains. This episode of fluvial sedimentation was terminated by a widespread marine transgression, as represented by the abrupt upward transition to the overlying shallow marine Sardhai Formation (Kungurian). The Early Permian Gondwana sequence represented by the Nilawahan Group is capped by predominantly shallow shelf carbonate deposits of the Tethyan realm. The sedimentologic and stratigraphic relationship of these four lithostratigraphic units in the Salt Range reveals a complex stratigraphic history for the Early Permian, which is mainly controlled by eustatic sea-level change due to climatic variation associated with climatic amelioration at the end of the major Gondwana glacial episode, and the gradual regional northward drift to a lower latitude of the Indian plate.

Ghazi, Shahid; Mountney, Nigel P.; Butt, Aftab Ahmad; Sharif, Sadaf

2012-10-01

254

Species of the medullosan ovule Stephanospermum from the Lopingian (late Permian) floras of China  

Science.gov (United States)

The medullosan pteridosperm ovule Stephanospermum Brongniart is a well-known component of Carboniferous aged coal-ball and siderite nodule floras from North America and Europe but also occurs in the Permian floras of Cathaysia where it is represented by the Lopingian (late Permian) aged species Stephanospermum trunctatum (Li) Wang et al. (2009) from coal-balls in the Wangjiazhai Formation in Southern China. We provide a detailed emendation of S. trunctatum and illustrate it comprehensively for the first time, and document an additional specimen from the Wangjiazhai Formation coal-ball assemblage that we assign to Stephanospermum shuichengensis sp. nov. S. shuichengensis is distinguished from S. trunctatum by the absence of apical teeth in the sclerotesta and non-obovate base. The two species of Stephanospermum from the Wangjiazhai Formation are important as they extend the stratigraphic and geographical range of the genus from the Pennsylvanian of Euramerica into the Lopingian of Southern China, and demonstrate that the genus persisted in wetland, peat forming environments in the run up to the end-Permian mass extinction event. The 44 MY stratigraphic discontinuity between the Euramerican and the Cathaysian species, here named the Stephanospermum gap, leads us to infer that the genus was likely to have occurred in the Pennsylvanian-Permian successions of southern Russia and northern China that are geographically and stratigraphically intermediate to the known occurrences but from which the genus has yet to be discovered. Medullosan pteridosperms appear to have become extinct at or immediately prior to the Permian-Triassic boundary that coincides with the Permo-Trias mass extinction event; although the exact causes of this loss in plant diversity remains unknown, a response to regional climatic drying is likely to have been a contributing factor.

Spencer, Alan R. T.; Wang, Shi-Jun; Dunn, Michael T.; Hilton, Jason

2013-10-01

255

Empirical model of temperature structure, Anadarko basin, Oklahoma  

Energy Technology Data Exchange (ETDEWEB)

Attempts at mapping the thermal structure of sedimentary basins most often are based on bottom-hole temperature (BHT) data. Aside from the inaccuracy of the BHT data itself, this approach uses a straight-line geothermal gradient, which is an unrealistic representation of the thermal structure. In fact, the temperature gradient is dependent upon the lithology of the rocks because each rock type has a different thermal conductivity. The mean gradient through a given sedimentary section is a composite of the gradients through the individual sedimentary units. Thus, a more accurate representation of the temperature variations within a basin can be obtained by calculating the temperature gradient through each layer of contrasting conductivity. In this study, synthetic temperature profiles are calculated from lithologic data interpreted from well logs, and these profiles are used to build a three-dimensional model of the temperature structure of the Anadarko basin. The lithologies that control the temperature in the Anadarko basin include very high-conductivity evaporites in the Permian, low-conductivity shales dominating the thick Pennsylvanian section, and relatively intermediate conductivity carbonates throughout the lower Paleozoic. Shale is the primary controlling factor because it is the most abundant lithology in the basin and has a low thermal conductivity. This is unfortunate because shale thermal conductivity is the factor least well constrained by laboratory measurements.

Gallardo, J.D.; Blackwell, D.D. (Southern Methodist Univ., Dallas, TX (USA))

1989-08-01

256

Tectonic structures of the Palo Duro basin, Texas Panhandle  

Energy Technology Data Exchange (ETDEWEB)

As part of an extensive basin analysis program conducted by the Bureau for the U.S. Department of Energy, this research summarizes the structural geology of the Palo Duro Basin. Surface and subsurface study, including examinations of outcrop, well log, and seismic reflection data, indicate that the structures within and adjoining the Palo Duro Basin consist primarily of isolated, fault-bounded, basement highs and poorly defined subbasins. Overall structural configuration of these features was produced during the Pennsylvanian Ancestral Rocky Mountain Orogeny and modified by subsidence during the Permian and Triassic Periods, although some structures formed before the late Paleozoic and were later reactivated. Recognized structures in the Palo Duro Basin include the Arney positive in Castro, Randall, and Swisher Counties, the central Randall High in Randall County, and the Littlefield-Illusion Lake structure in Lamb County. Structures marginal to the Palo Duro Basin include the Amarillo Uplift, Whittenburg Trough, Oldham-Harmon trend, and the Matador Arch; in this report the author delineates these and other structures in detail.

1989-01-01

257

Occurrence and origin of minerals in a chamosite-bearing coal of Late Permian age, Zhaotong, Yunnan, China  

Energy Technology Data Exchange (ETDEWEB)

The minerals found in the no. 5 coal (Late Permian) from the Zhaotong Coalfield, Yunnan Province, southwestern China, have been examined and found to consist mainly of kaolinite, pyrite, chamosite, quartz, and calcite, with trace amounts of illite and mixed-layer illite-smectite. The proportion of chamosite in clay minerals ranges from 32 to 56 wt%, with an average of 46 wt%. Chamosite is distributed not only in collodetrinite, but also occurs as cell fillings in fusinite, semifusinite, and telinite. The high content and mode of occurrence of chamosite in this mine indicate its formation by interaction of kaolinite with Fe-Mg-rich fluids during early diagenesis. Except for a minor amount of terrigenous quartz, most quartz is of authigenic origin and formed from kaolinite desilication. The calcite content of the no. 5 coal is 1.4-6.3% (with an average of 3%) and is distributed in collodetrinite and as cell fillings of coal-forming plants. Calcite originated from seawater invasion during peat accumulation. Pyrite occurs in several ways: as massive, framboidal, isolated enhedral/anhedral, and euhedral forms. In addition, the presence of a large amount of pyritized red algae provides strong evidence of seawater invasion during peat accumulation. The red algae may have played an important role in the enrichment of sulfur in the coal. The characteristic assemblage of minerals in this mine resulted from a unique basinal environment in which the mineral matter was derived from a basaltic source region, volcanic activity, and seawater transgression during coal formation.

Dai, S.; Chou, C.L. [China University of Mining and Technology, Beijing (China)

2007-08-15

258

Late Palaeozoic palynomorph assemblages from the Karoo Supergroup and their potential for biostratigraphic correlation, Kalahari Karoo Basin, Botswana  

Directory of Open Access Journals (Sweden)

Full Text Available Late Carbonifeous to Permian core samples from two borehole sections, STRAT 1 and CKP 6, that penetrate the glacial to postglacial and coal-bearing Lower Karoo sequence, Kalahari Karoo Basin, Botswana, contain well preserved pollen and spore palynomorphs. The palynomorph assemblages comprise 165 species of spores and pollen, and few acritarchs and chlorophycean algae. This paper presents a local biozonation of three succeeding assemblage zones, recognisable in each borehole section. The assemblage zones are named: the Hamiapollenites bullaeformis Biozone, the Cyclogranisporites gondwanensis Biozone and the Platysaccus papilionis-Striatopodocarpites fusus Biozone, in ascending order of stratigraphy. Assemblages are compared and correlated with assemblages described from other Gondwana areas of Africa, Australia, Arabia, South America and Antarctica. A general analysis of taxa from the Kalahari Karoo Basin indicates a distinct similarity with assemblages from the Paraná Basin of South America. The Hamiapollenites bullaeformis Biozone is comparable with the Vittatina costabilis Interval Zone of the Paraná Basin. Assemblages from the Cyclogranisporites gondwanensis and the Platysaccus papilionis-Striatopodocarpites fusus zones are comparable with the Lueckisporites virkkiae Interval Zone. Age determination for the assemblages in the Kalahari Karoo Basin is inferred from comparison with similar assemblages from previous Gondwana studies, and ranges from the Late Carboniferous (Kasimovian-Gzhelian) to latest Early or possibly earliest Middle Permian (Late Cisularian to Early Guadalupian).

Modie B N; Le Hérissé A

2009-01-01

259

Heat flow and thermal history of the Anadarko basin, Oklahoma  

Science.gov (United States)

New heat-flow values for seven sites in the Anadarko basin, Oklahoma, were determined using high-precision temperature logs and thermal conductivity measurements from nearly 300 core plugs. Three of the sites are on the northern shelf, three sites are in the deep basin, and one site is in the frontal fault zone of the northern Wichita Mountains. The heat flow decreased from 55 to 64 mW/m2 in the north, and from 39 to 54 mW/m2 in the south, due to a decrease in heat generation in the underlying basement rock toward the south. Lateral lithologic changes in the basin, combined with the change in heat flow across the basin, resulted in an unusual pattern of thermal maturity. The vitrinite reflectance values of the Upper Devonian-Lower Mississippian Woodford formation are highest 30-40 km north-northwest of the deepest part of the basin. The offset in highest reflectance values is due to the contrast in thermal conductivity between the Pennsylvanian "granite wash" section adjacent to the Wichita uplift and the Pennsylvanian shale section to the north. The geothermal gradient in the low-conductivity shale section is elevated relative to the geothermal gradient in the high-conductivity "granite wash" section, thus displacing the highest temperatures to the north of the deepest part of the basin. Apatite fission-track, vitrinite reflectance, and heat-flow data were used to constrain regional aspects of the burial history of the Anadarko basin. By combining these data sets, we infer that at least 1.5 km of denudation has occurred at two sites in the deep Anadarko basin since the early to middle Cenozoic (40 ?? 10 m.y.). The timing of the onset of denudation in the southern Anadarko basin coincides with the period of late Eocene erosion observed in the southern Rocky Mountains and in the northern Great Plains. Burial history models for two wells from the deep Anadarko basin predict that shales of the Woodford formation passed through the hydrocarbon maturity window by the end of the Permian section in the deep basin moved into the hydrocarbon maturity window during Mesozoic burial of the region. Presently, the depth interval of the main zone of oil maturation (% Ro = 0.7-0.9) is approximately 2800-3800 m in the eastern deep basin basin and 2200-3000 m in the western deep basin. The greater depth to the top of the oil maturity zone and larger depth range of the zone in the eastern part of the deep basin are due to the lower heat flow associated with more mafic basement toward the east. The burial history model for the northern shelf indicates that the Woodford formation has been in the early oil maturity zone since the Early Permian.

Carter, L. S.; Kelley, S. A.; Blackwell, D. D.; Naeser, N. D.

1998-01-01

260

A natural analogue for copper waste canisters: The copper-uranium mineralised concretions in the Permian mudrocks of south Devon, United Kingdom  

International Nuclear Information System (INIS)

[en] This report presents the results of a small-scale pilot study of the mineralogy and alteration characteristics of unusual sheet-like native copper occurring together with uraniferous and vanadiferous concretions in mudstones and siltstones of the Permian Littleham Mudstone Formation, at Littleham Cove, south Devon, England. The host mudstones and siltstones are smectitic and have been compacted through deep Mesozoic burial. The occurrence of native copper within these rocks represents a natural analogue for the long-term behaviour of copper canisters, sealed in a compacted clay (bentonite) backfill, that will be used for the deep geological disposal of high-level radioactive waste by the SKB. The study was undertaken by the British Geological Survey (BGS) on behalf of SKB between November 1999 and June 2000. The study was based primarily on archived reference material collected by the BGS during regional geological and mineralogical surveys of the area in the 1970's and 1980's. However, a brief visit was made to Littleham Cove in January 2000 to try to examine the native copper in situ and to collect additional material. Unfortunately, recent landslips and mudflows obscured much of the outcrop, and only one new sample of native copper could be collected. The native copper occurs as thin plates, up to 160 mm in diameter, which occur parallel to bedding in the Permian Littleham Mudstone Formation at Littleham Cove (near Budleigh Salterton) in south Devon. Each plate is made up of composite stacks of individual thin copper sheets each 1-2 mm thick. The copper is very pure (>99.4% Cu) but is accompanied by minor amounts of native silver (also pure - >99%) which occurs as small inclusions within the native copper. Detailed mineralogical and petrological studies of the native copper sheets, using optical petrography, backscattered scanning electron microscopy, X-ray diffraction analysis and electron probe microanalytical techniques, reveal a complex history of mineralisation and alteration that can be related to the burial and diagenetic history of the Permian strata. The native copper mineralisation exhibits close temporal association with the formation of uraniferous and vanadiferous concretions (known as 'fish-eyes') in the same rocks. Petrographical relationships indicate that both the copper and the 'fish-eye' concretions formed during burial diagenesis but before the maximum compaction of the host mudstone and siltstone. The regional burial history Wessex Basin, indicates that the maximum compaction of the Permian strata would have been achieved by at least the end of the Lower Jurassic (possibly even in the Triassic). Therefore, the native copper mineralisation is older than 176 Ma. The native copper sheets display a complex sequence of alteration and subsequent mineral growth of minerals on their surfaces. The earliest alteration was to copper oxides - principally cuprite with minor tenorite, indicating a change to more oxidising groundwater conditions. The dissolution of native silver and the growth of fringes of copper arsenides followed this. Nickel arsenides and chalcocite, associated with the precipitation of uranium silicates occurred in the later stages of alteration. This suggests a return to a more reducing pore water environment. Again, petrographical relationships indicate that this alteration and subsequent mineralisation is geologically old (i.e. Lower Jurassic or older). Secondary malachite, intimately intergrown copper sulphate and copper oxides, copper chloride, copper-uranium arsenate and uranium vanadates have formed as late-stage alteration products of the native copper and earlier diagenetic cuprite, chalcocite, copper-nickel arsenide and uranium silicate alteration and mineralisation. This latest stage alteration is most probably attributable to near-surface weathering processes. Although the native copper is affected by corrosion, the study has shown that a significant proportion (30-80% of the original thickness) of the copper sheets has been preserved in the saturated compacted clay en

2000-01-01

 
 
 
 
261

A natural analogue for copper waste canisters: The copper-uranium mineralised concretions in the Permian mudrocks of south Devon, United Kingdom  

Energy Technology Data Exchange (ETDEWEB)

This report presents the results of a small-scale pilot study of the mineralogy and alteration characteristics of unusual sheet-like native copper occurring together with uraniferous and vanadiferous concretions in mudstones and siltstones of the Permian Littleham Mudstone Formation, at Littleham Cove, south Devon, England. The host mudstones and siltstones are smectitic and have been compacted through deep Mesozoic burial. The occurrence of native copper within these rocks represents a natural analogue for the long-term behaviour of copper canisters, sealed in a compacted clay (bentonite) backfill, that will be used for the deep geological disposal of high-level radioactive waste by the SKB. The study was undertaken by the British Geological Survey (BGS) on behalf of SKB between November 1999 and June 2000. The study was based primarily on archived reference material collected by the BGS during regional geological and mineralogical surveys of the area in the 1970's and 1980's. However, a brief visit was made to Littleham Cove in January 2000 to try to examine the native copper in situ and to collect additional material. Unfortunately, recent landslips and mudflows obscured much of the outcrop, and only one new sample of native copper could be collected. The native copper occurs as thin plates, up to 160 mm in diameter, which occur parallel to bedding in the Permian Littleham Mudstone Formation at Littleham Cove (near Budleigh Salterton) in south Devon. Each plate is made up of composite stacks of individual thin copper sheets each 1-2 mm thick. The copper is very pure (>99.4% Cu) but is accompanied by minor amounts of native silver (also pure - >99%) which occurs as small inclusions within the native copper. Detailed mineralogical and petrological studies of the native copper sheets, using optical petrography, backscattered scanning electron microscopy, X-ray diffraction analysis and electron probe microanalytical techniques, reveal a complex history of mineralisation and alteration that can be related to the burial and diagenetic history of the Permian strata. The native copper mineralisation exhibits close temporal association with the formation of uraniferous and vanadiferous concretions (known as 'fish-eyes') in the same rocks. Petrographical relationships indicate that both the copper and the 'fish-eye' concretions formed during burial diagenesis but before the maximum compaction of the host mudstone and siltstone. The regional burial history Wessex Basin, indicates that the maximum compaction of the Permian strata would have been achieved by at least the end of the Lower Jurassic (possibly even in the Triassic). Therefore, the native copper mineralisation is older than 176 Ma. The native copper sheets display a complex sequence of alteration and subsequent mineral growth of minerals on their surfaces. The earliest alteration was to copper oxides - principally cuprite with minor tenorite, indicating a change to more oxidising groundwater conditions. The dissolution of native silver and the growth of fringes of copper arsenides followed this. Nickel arsenides and chalcocite, associated with the precipitation of uranium silicates occurred in the later stages of alteration. This suggests a return to a more reducing pore water environment. Again, petrographical relationships indicate that this alteration and subsequent mineralisation is geologically old (i.e. Lower Jurassic or older). Secondary malachite, intimately intergrown copper sulphate and copper oxides, copper chloride, copper-uranium arsenate and uranium vanadates have formed as late-stage alteration products of the native copper and earlier diagenetic cuprite, chalcocite, copper-nickel arsenide and uranium silicate alteration and mineralisation. This latest stage alteration is most probably attributable to near-surface weathering processes. Although the native copper is affected by corrosion, the study has shown that a significant proportion (30-80% of the original thickness) of the copper sheets has been preserved in the s

Milodowski, A.E.; Styles, M.T.; Hards, V.L. [Natural Environment Research Council (United Kingdom). British Geological Survey

2000-08-01

262

Trace elemental analysis of permian gondwana coals in Bangladesh by PIXE technique  

International Nuclear Information System (INIS)

[en] The study of trace elements level in coal arouses much interest days to assess and evaluate the environmental impact related to its benefit and usage in applying it to the problem of mining site. Further, it is more important during the coal combustion in thermal power stations particularly in relation to the emission of air toxic, disposal and utilization of fly ash. The paper describes the level of nineteen environmentally significant trace elements found in recently discovered Permian Gondwana coals in Barapukuria and Khalaspir of Northwestern Bangladesh using Proton Induced X-ray Emission (PIXE) spectroscopy. Both the mineral species and trace elements are expected to be due to sedimentary and aerobic environmental condition where the Permian coals have been generated depending on their degree of evolution. (author)

2004-01-01

263

Geochemical changes at the Permian–Triassic transition in Southern Alps and adjacent area: a review  

Directory of Open Access Journals (Sweden)

Full Text Available Compilation of the recent literature from the Southern Alps and adjacent area confirms the geochemical variations of unusual amplitudes during the Permian-Triassic boundary interval (PTBI). A great attention has been given to the negative ?13C anomaly within the Tesero Member close to the Permian-Triassic boundary. Very detailed geochemical works have been done on the scientific Gartnerkofel core (Gk-1) and on the Slovenian sections. Major minor and rare earth elements (REE) data are reported and show a marked enrichment in alkaline metals and REE of some levels of the boundary interval. But recent studies show that the low Iridium anomalies and the Osmium and Helium isotopes anomalies lack the characteristics of a large extraterrestrial impact.

Aymon Baud

2005-01-01

264

Sulfur and oxygen isotopes in Italian marine sulfates of Permian and Triassic ages  

Energy Technology Data Exchange (ETDEWEB)

Evaporitic sulfates of Permian and Triassic ages from Italian occurrences were analyzed for sulfur and oxygen isotopes in order to supplement the corresponding isotope-age curves and to use isotopic data to trace the origin of the sulfate in hydrologic systems. The sulfur-isotopic composition-age relationships obtained in this study generally agree with those found throughout the world. In two cases, i.e. in samples from the Carniola di Bovegno Formation (Bergamo and Brescia Alps) and from the lower part of the Gracilis Formation (Recoaro, Vicenza), sulfur isotopes suggest different ages for the rocks than the formerly ascribed ones. Oxygen-isotopic compositions show the same range from approximately +10.5 to +18.5per thousand, without any consistent relationship with sulfur. These ranges of values are almost identical to those published previously for sulfates of Permian and Triassic ages from other locations.

Cortecci, G.; Reyes, E.; Berti, G. (Pisa Univ. (Italy)); Casati, P. (Milan Univ. (Italy))

1981-11-01

265

Permian reefs of Texas and New Mexico: history of their study and scientific influence  

Energy Technology Data Exchange (ETDEWEB)

No fossil reef has more influenced thinking on carbonate and evaporite deposition, paleontology, paleoecology, and accumulation of petroleum than the Permian reefs of Texas and New Mexico. Study of the reefs can be divided into six fairly distinct periods. Little attention was given these Permian rocks, following discovery in 1855, until work by Girty and Richardson resulted in the monumental Guadalupian Fauna. Their study and those of Udden, Darton, Baker and others typify the first period. Discovery of oil in Permian rocks in Winkler County, Texas in 1926 initiated the second period, one when outcrops in the Guadalupe Mountains and elsewhere were examined to help explain puzzling stratigraphic relationships seen in the subsurface. E.R. Lloyd published in 1929 that the Capitan Limestone was a reef. The third period was dominated by P.B. and R.E. King and their colleagues. It was a time of geologic mapping and stratigraphic study. Adams et al. proposed Permian series based on sections in the Glass and Guadalupe Mountains. The fourth period is characterized by the classic study of Newell and his associates and was a time of paleoecologic and paleontologic work. Seminal studies by industry geologists, such as Dunham (Shell) and Pray and Tyrrell (Amoco) typify the fifth period. Dunham's work, in particular, spurred study of massive reef and bedded shelf facies and reef profiles. The sixth period is characterized by continuing detailed study of physical aspects of reef and shelf rocks by University of Wisconsin students and faculty, although they have also included work on algae and conodonts.

Rigby, J.K.

1985-01-01

266

Study of association of fossil levels in the Mangrullo Formation (Terminal Permian age) Uruguay  

International Nuclear Information System (INIS)

This contribution makes reference to new findings, product of paleontological surveys performed in the Mangrullo Formation in the NE region of the country. The presence of a new group of vertebrates associated to mesosaurid remains was confirmed , in strata where only the latter where recorded until this moment. Palynological analysis were carried out in fossil bearing levels confirming a Terminal Permian Age and a possibly non marine acuatic depostional environment under an arid climate. (author)

1998-01-01

267

Geochemical anomalies near the Eocene-Oligocene and Permian-Triassic boundaries  

Energy Technology Data Exchange (ETDEWEB)

Evidence is presented to support the theory that several mass extinctions, i.e., those that define the Permian-Triassic boundary, the Cretaceous-Tertiary boundary, and the Eocene-1 Oligocene boundary, were caused by impact on the earth of extraterrestrial objects having the composition of carbonaceous chondrites and diameters of about 10 km. The evidence consists of anomalously high concentrations of iridium and other siderophile elements at the stratigraphic levels defining the extinctions. (ACR)

Asaro, F.; Alvarez, L.W.; Alvarez, W.; Michel, H.V.

1981-10-01

268

Tectonic and climatic controls on sedimentation during deposition of the Sinakumbe Group and Karoo Supergroup in the mid-Zambezi Valley Basin, southern Zambia  

Energy Technology Data Exchange (ETDEWEB)

Sediments of the Ordovician to Devonian Sinakumbe Group (about 210 m thick) and overlying Upper Carboniferous to Lower Jurassic Karoo Supergroup (about 4.5 km thick) were deposited in the mid-Zambezi Rift Valley Basin, southern Zambia. The Sinakumbe-Karoo succession represents deposition in a extensional fault-controlled basin of half-graben type. The basin-fill succession incorporates two major fining-upward cycles that resulted from major tectonic events, one event beginning with Sinakumbe Group sedimentation, possibly as early as Ordovician times, and the other beginning with Upper Karoo Group sedimentation near the Permo-Triassic boundary. Minor tectonic pulses occurred during deposition of the two major cycles. Glaciation followed by deglaciation resulted in glaciofluvial and glacio-lacustrine deposits of the Upper Carboniferous to Lower Permian Siankondobo Sandstone Formation of the Lower Karoo Group, and isostatic rebound eventually produced a broad flood plain on which the coal-bearing Lower Permian Gwembe Coal Formation was deposited. Fault-controlled maximum subsidence is represented by the lacustrine Upper Permian Madumabisa Mudstone Formation. Block-faulting and downwarping culminated with the introduction of large quantities of sediment through braided fluvial systems. Outpourings of basaltic flows in the Early Jurassic terminated Karoo sedimentation.

Nyambe, I.A. (University of Zambia, Lusaka (Zambia). Dept. of Geology)

1999-02-01

269

A new Early Permian reptile and its significance in early diapsid evolution.  

UK PubMed Central (United Kingdom)

The initial stages of evolution of Diapsida (the large clade that includes not only snakes, lizards, crocodiles and birds, but also dinosaurs and numerous other extinct taxa) is clouded by an exceedingly poor Palaeozoic fossil record. Previous studies had indicated a 38 Myr gap between the first appearance of the oldest diapsid clade (Araeoscelidia), ca 304 million years ago (Ma), and that of its sister group in the Middle Permian (ca 266 Ma). Two new reptile skulls from the Richards Spur locality, Lower Permian of Oklahoma, represent a new diapsid reptile: Orovenator mayorum n. gen. et sp. A phylogenetic analysis identifies O. mayorum as the oldest and most basal member of the araeoscelidian sister group. As Richards Spur has recently been dated to 289 Ma, the new diapsid neatly spans the above gap by appearing 15 Myr after the origin of Diapsida. The presence of O. mayorum at Richards Spur, which records a diverse upland fauna, suggests that initial stages in the evolution of non-araeoscelidian diapsids may have been tied to upland environments. This hypothesis is consonant with the overall scant record for non-araeoscelidian diapsids during the Permian Period, when the well-known terrestrial vertebrate communities are preserved almost exclusively in lowland deltaic, flood plain and lacustrine sedimentary rocks.

Reisz RR; Modesto SP; Scott DM

2011-12-01

270

Permian vegetational Pompeii from Inner Mongolia and its implications for landscape paleoecology and paleobiogeography of Cathaysia.  

UK PubMed Central (United Kingdom)

Plant communities of the geologic past can be reconstructed with high fidelity only if they were preserved in place in an instant in time. Here we report such a flora from an early Permian (ca. 298 Ma) ash-fall tuff in Inner Mongolia, a time interval and area where such information is filling a large gap of knowledge. About 1,000 m(2) of forest growing on peat could be reconstructed based on the actual location of individual plants. Tree ferns formed a lower canopy and either Cordaites, a coniferophyte, or Sigillaria, a lycopsid, were present as taller trees. Noeggerathiales, an enigmatic and extinct spore-bearing plant group of small trees, is represented by three species that have been found as nearly complete specimens and are presented in reconstructions in their plant community. Landscape heterogenity is apparent, including one site where Noeggerathiales are dominant. This peat-forming flora is also taxonomically distinct from those growing on clastic soils in the same area and during the same time interval. This Permian flora demonstrates both similarities and differences to floras of the same age in Europe and North America and confirms the distinct character of the Cathaysian floral realm. Therefore, this flora will serve as a baseline for the study of other fossil floras in East Asia and the early Permian globally that will be needed for a better understanding of paleoclimate evolution through time.

Wang J; Pfefferkorn HW; Zhang Y; Feng Z

2012-03-01

271

Petroleum potential and stratigraphy of Holitna basin, Alaska  

Energy Technology Data Exchange (ETDEWEB)

The Holitna basin, an interior Alaskan basin, is flanked by Cambrian to cretaceous sedimentary rocks that have been highly folded and faulted. Gravity mapping and modeling indicate up to 15,000 ft of sedimentary section is present within the basin. Cambrian rocks consist of trilobite-hash lime mudstone, red siltstone, and basinal chert. Ordovician through Devonian basinal facies rocks consist of platy limestone to graptolitic shale with minor interbeds of limestone turbidites and turbidite-channel debris flows. Ordovician through Middle Devonian shallow-water platform carbonate rocks prograde over the basinal rocks and are composed of algal boundstone buildups with associated inboard lagoonal, oolitic shoal, and tidal-channel deposits. Toward the interior of the platform, restricted subtidal and intertidal to supratidal carbonate rocks were deposited. Upper Devonian to Permian platform carbonate deposition occurred to the east of the older platform rocks and conformably(.) over basinal rocks. Minor mixed carbonate-clastic deposition occurred into Triassic time. The Cretaceous Kuskokwim Group is in fault contact with and/or unconformably overlies the Paleozoic carbonates. This unit varies from lithic-rich conglomerates to marine turbidite deposits. Maturation values for Cretaceous and Paleozoic rocks are within the oil window, with most of the shales showing a thermal alteration index (TAI) from 2 to 3. Organic carbon content exceeds 3% in some samples, however, deep surface weathering has resulted in low hydrocarbon values. The lithic-rich Cretaceous sandstones are well indurated, poorly sorted, and are considered to have low reservoir potential. Partly dolomitized, shallow-water Ordovician to Devonian carbonate rocks are the best potential reservoir rocks exhibiting vuggy porosities greater than 10% and good intergranular porosity.

Smith, T.N.; Clough, J.G.; Meyer, J.F.; Blodgett, R.B.

1985-02-01

272

Evolution of overpressured and underpressured oil and gas reservoirs, Anadarko Basin of Oklahoma, Texas, and Kansas  

Science.gov (United States)

Departures of resistivity logs from a normal compaction gradient indicate that overpressure previously extended north of the present-day overpressured zone. These indicators of paleopressure, which are strongest in the deep basin, are mapped to the Kansas-Oklahoma border in shales of Desmoinesian age. The broad area of paleopressure has contracted to the deep basin, and today the overpressured deep basin, as determined from drillstem tests, is bounded on the north by strata with near normal pressures (hydrostatic), grading to the northwest to pressures that are less than hydrostatic (underpressured). Thus the pressure regime in the northwest portion of the Anadarko Basin has evolved from paleo-overpressure to present-day underpressure. Using pressure data from drillstem tests, we constructed cross sections and potentiometric maps that illustrate the extent and nature of present-day underpressuring. Downcutting and exposure of Lower Permian and Pennsylvanian strata along, and east of, the Nemaha fault zone in central Oklahoma form the discharge locus where pressure reaches near atmospheric. From east to west, hydraulic head increases by several hundred feet in each rock formation, whereas elevation increases by thousands of feet. The resulting underpressuring of the aquifer-supported oil and gas fields, which also increases from east to west, is a consequence of the vertical separation between surface elevation and hydraulic head. A 1,000-ft thick cap of Permian evaporites and shales isolates the underlying strata from the surface, preventing re-establishment of a normal hydrostatic gradient. Thus, the present-day pressure regime of oil and gas reservoirs, overpressured in the deep basin and underpressured on the northwest flank of the basin, is the result of two distinct geologic events-rapid burial and uplift/erosion-widely separated in time.

Nelson, Phillip H.; Gianoutsos, Nicholas J.

2011-01-01

273

Regional magnetotelluric surveys in hydrocarbon exploration, Parana' Basin, Brazil  

Energy Technology Data Exchange (ETDEWEB)

The magnetotelluric geophysical method has been used effectively as a hydrocarbon exploration tool in the intracratonic Parana basin of South America. The 1-2 km thick surface basalts and buried diabase sills pose no problem for the magnetotelluric method because the natural electromagnetic fields used as the energy source pass easily through the basalt. Data for the regional study were taken on six profiles with soundings spaced 8 to 15 km apart. The magnetotelluric sounding data outline a linear uplift known as the Ponta Grossa arch. This major structural feature cuts across the northeast-trending intracratonic basin almost perpendicularly, and is injected with numerous diabase dikes. In the survey area, MT interpretations show that basalts have aggregate thicknesses of as much as 2 km (6,600 ft), and basement may be as much as 6 km (20,000 ft) below the surface. Over most of the basin, the basalts are covered by Upper Cretaceous to Holocene continental sediments of a few hundred meters thickness and are underlain by 2 to 4 km (6,600 to 13,100 ft) thick Paleozoic sediments with possible hydrocarbon potential. Significant electrical contrasts occur between the Permian sediments and older units, so that magnetotelluric measurements can give an indication of the regional thickness of the Permian and younger sediments to aid in interpreting hydrocarbon migration patterns and possible trap areas.

Stanley, W.D.; Ohofugi, W.; Saad, A.R.

1985-03-01

274

Middle Carboniferous fusulinacean biostratigraphy, northern Ellesmere Island (Sverdrup Basin, Canadian Arctic Archipelago)  

Energy Technology Data Exchange (ETDEWEB)

It is generally considered that Carboniferous and Permian strata in the Sverdrup Basin and elsewhere in the circum-Arctic regions of the world have significant petroleum potential. The Sverdrup Basin is an elongate pericratonic depression underlying much of the Canadian Arctic Archipelago. The oldest rocks in the basin, nonmarine marlstones that constitute the Visean Emma Fiord Formation, occur in isolated structural depressions along the southern margin and in the centre of the basin. The Borup Fiord Formation, consisting mainly of marine and nonmarine siliciclastics, was the first widespread sedimentary unit to be deposited following initial rifting and collapse of the basin. At its type section on northern Ellesmere Island, the Borup Fiord Formation contains a thin marine limestone with biseriamminid and asteroarchaediscid foraminifers of Serpukhovian age. This limestone is the only datable unit in the whole Borup Fiord Formation. Continued rifting and subsidence of the the Sverdrup Basin led to predominantly marine conditions, which are recorded at the basin margins by a thick succession of bioclastic limestone belonging to the Nansen Formation. The presence of primitive fusilinaceans from the lower several meters of the Nansen and its type strongly suggests an early Bashkirian age. Erosional relief, coupled with biostratigraphic evidence, indicates an unconformable contact between the Borup Fiord and Nansen formations. Successively higher deposits within the lower 350 m of the Nansen are characterized by fusilinacean assemblages that range from Bashkirian through early late Moscovian time. 160 refs., 11 figs., 1 tab.

Grooves, J.R.; Nassichuk, W.W.; Lin Rui; Pinard, S.

1994-01-01

275

The origin of the top surface of Carboniferous in the Upper Silesian Coal Basin  

Energy Technology Data Exchange (ETDEWEB)

In the Upper Silesian coal basin, the upper boundary of the coal-bearing Carboniferous strata is an erosive surface covered by patches of deposits of different age. Locally, this surface and its overburden are cut by post-Carboniferous faults. The study of this top surface of Carboniferous is important for recognition of the extent of coal seam outcrops at this surface, for studying the nature of the Carboniferous-Permian boundary and of the origin of this discordant surface. 8 refs., 2 figs.

Jura, D.

1988-01-01

276

Thermal history of the periphery of the Junggar Basin, Northwestern China  

Science.gov (United States)

Geochemical analysis of rock core samples show that the basin periphery has experienced low thermal stress; present-day heat flows are in the range of 25-35 mW/m2 and have not been significantly higher than the worldwide mean of approx. 63 mW/m2 since the mid-Permian. Present day heat flows were determined from corrected borehole temperatures and rock thermal conductivities. Paleo-heat flows were determined by first-order reaction kinetic modeling of several geochemical paleothermometers (vitrinite reflectance, clay mineral diagenesis and relative proportions of sterane and hopane biological marker diastereomers). ?? 1994.

King, J. D.; Yang, J.; Pu, F.

1994-01-01

277

Dissolution of the Upper Seven Rivers and Salado salt in the interior Palo Duro Basin, Texas: Revision: Topical report  

Energy Technology Data Exchange (ETDEWEB)

The Upper Seven Rivers and Salado Formations contain the uppermost salts within the interior Palo Duro Basin, Stratigraphic and structural evidence based on geophysical well logs indicate that both dissolution and facies change have influenced the thickness of these uppermost salts. The magnitude of vertical salt loss due to dissolution is interminable at this time because original salt thickness is unknown. Gradual thinning of the Upper Seven Rivers Formation is recognized from south to north across the Palo Duro Basin. Anhydrites within the formation pinch out toward the basin margins, indicating that section loss is in part depositionally controlled. Additionally, informal subdivision of the Upper Seven Rivers Formation suggests that salt dissolution has occurred in the uppermost salt. A northeast-trending zone of thin Upper Seven Rivers Formation in portions of Deaf Smith, Randall, Castro, and Parmer Counties is possibly related to Tertiary dissolution. In New Mexico, local thinning of the Upper Seven Rivers Formation may be associated with faulting. Triassic erosion on uplifted fault blocks has affected the Upper Permian section. The Salado salt margin is located within the interior Palo Duro Basin. Geophysical well logs and core evidence indicate that the salt margin has migrated basinward as a result of dissolution. Permian dissolution probably contributed to some salt loss. 106 refs., 31 figs., 2 tabs.

DeConto, R.T.; Murphy, P.J.

1987-09-01

278

Dissolution of the Upper Seven Rivers and Salado salt in the interior Palo Duro Basin, Texas: Revision: Topical report  

International Nuclear Information System (INIS)

[en] The Upper Seven Rivers and Salado Formations contain the uppermost salts within the interior Palo Duro Basin, Stratigraphic and structural evidence based on geophysical well logs indicate that both dissolution and facies change have influenced the thickness of these uppermost salts. The magnitude of vertical salt loss due to dissolution is interminable at this time because original salt thickness is unknown. Gradual thinning of the Upper Seven Rivers Formation is recognized from south to north across the Palo Duro Basin. Anhydrites within the formation pinch out toward the basin margins, indicating that section loss is in part depositionally controlled. Additionally, informal subdivision of the Upper Seven Rivers Formation suggests that salt dissolution has occurred in the uppermost salt. A northeast-trending zone of thin Upper Seven Rivers Formation in portions of Deaf Smith, Randall, Castro, and Parmer Counties is possibly related to Tertiary dissolution. In New Mexico, local thinning of the Upper Seven Rivers Formation may be associated with faulting. Triassic erosion on uplifted fault blocks has affected the Upper Permian section. The Salado salt margin is located within the interior Palo Duro Basin. Geophysical well logs and core evidence indicate that the salt margin has migrated basinward as a result of dissolution. Permian dissolution probably contributed to some salt loss. 106 refs., 31 figs., 2 tabs

1987-01-01

279

Supai salt karst features: Holbrook Basin, Arizona  

Energy Technology Data Exchange (ETDEWEB)

More than 300 sinkholes, fissures, depressions, and other collapse features occur along a 70 km (45 mi) dissolution front of the Permian Supai Formation, dipping northward into the Holbrook Basin, also called the Supai Salt Basin. The dissolution front is essentially coincident with the so-called Holbrook Anticline showing local dip reversal; rather than being of tectonic origin, this feature is likely a subsidence-induced monoclinal flexure caused by the northward migrating dissolution front. Three major areas are identified with distinctive attributes: (1) The Sinks, 10 km WNW of Snowflake, containing some 200 sinkholes up to 200 m diameter and 50 m depth, and joint controlled fissures and fissure-sinks; (2) Dry Lake Valley and contiguous areas containing large collapse fissures and sinkholes in jointed Coconino sandstone, some of which drained more than 50 acre-feet ({approximately}6 {times} 10{sup 4} m{sup 3}) of water overnight; and (3) the McCauley Sinks, a localized group of about 40 sinkholes 15 km SE of Winslow along Chevelon Creek, some showing essentially rectangular jointing in the surficial Coconino Formation. Similar salt karst features also occur between these three major areas. The range of features in Supai salt are distinctive, yet similar to those in other evaporate basins. The wide variety of dissolution/collapse features range in development from incipient surface expression to mature and old age. The features began forming at least by Pliocene time and continue to the present, with recent changes reportedly observed and verified on airphotos with 20 year repetition. The evaporate sequence along interstate transportation routes creates a strategic location for underground LPG storage in leached caverns. The existing 11 cavern field at Adamana is safely located about 25 miles away from the dissolution front, but further expansion initiatives will require thorough engineering evaluation.

Neal, J.T.

1994-12-31

280

Basin-centered gas accumulation in the Timan-Pechora Basin, Russia  

Energy Technology Data Exchange (ETDEWEB)

As a consequence of the USAID-funded program between the USGS and ROSCOMNEDRA, a very large basin-centered gas accumulation has been identified in Permian orogenic flysch and molasse rocks in the pre-Ural (Kosyu-Rogov) depression of the Timan-Pechora Basin, Russia. In the Timan-Pechora Basin the Artinskian, Kungurian, and Ufimian (Leonardian-Guadalupian) gas-bearing sequence is as thick as 2,000 in and is composed of interbedded sandstone, siltstone, shale, and coal. Sandstone porosity ranges from 3 to 15% and permeability is commonly less than 0.1 md. Drill-stem and production tests indicate that these rocks are gas saturated with little or no producible water. Pore pressures are abnormally high with gradients of about 0.50 to 0.60 psi/ft. The source of the gas is most likely the interbedded coals and other carbonaceous lithologies. The organic carbon content of these rocks, exclusive of coal, ranges from <0.2 to 4.0 weight percent, averaging 1.5%. The top of the gas accumulation is interpreted to cut across structural and stratigraphic boundaries similar to basin-centered gas accumulations in North America. However, south of the Kosyu-Rogov depression, coal-bearing Kungurian rocks have undergone a facies change into evaporates, forming a regional seal that extends southward into the Volga-Ural Province. The southern extent of the gas accumulation below the evaporate seal is unknown, but it may extend far to the south, making it one of the largest gas accumulations in the world.

Law. B.E. [Geological Survey, Denver, CO (United States); Bogatsky, V.; Danileksky, S.; Galkina, L. [TPO, VNIGRI, Ukhta (Russian Federation)] [and other

1996-12-31

 
 
 
 
281

Basin-centered gas accumulation in the Timan-Pechora Basin, Russia  

Energy Technology Data Exchange (ETDEWEB)

As a consequence of the USAID-funded program between the USGS and ROSCOMNEDRA, a very large basin-centered gas accumulation has been identified in Permian orogenic flysch and molasse rocks in the pre-Ural (Kosyu-Rogov) depression of the Timan-Pechora Basin, Russia. In the Timan-Pechora Basin the Artinskian, Kungurian, and Ufimian (Leonardian-Guadalupian) gas-bearing sequence is as thick as 2,000 in and is composed of interbedded sandstone, siltstone, shale, and coal. Sandstone porosity ranges from 3 to 15% and permeability is commonly less than 0.1 md. Drill-stem and production tests indicate that these rocks are gas saturated with little or no producible water. Pore pressures are abnormally high with gradients of about 0.50 to 0.60 psi/ft. The source of the gas is most likely the interbedded coals and other carbonaceous lithologies. The organic carbon content of these rocks, exclusive of coal, ranges from <0.2 to 4.0 weight percent, averaging 1.5%. The top of the gas accumulation is interpreted to cut across structural and stratigraphic boundaries similar to basin-centered gas accumulations in North America. However, south of the Kosyu-Rogov depression, coal-bearing Kungurian rocks have undergone a facies change into evaporates, forming a regional seal that extends southward into the Volga-Ural Province. The southern extent of the gas accumulation below the evaporate seal is unknown, but it may extend far to the south, making it one of the largest gas accumulations in the world.

Law. B.E. (Geological Survey, Denver, CO (United States)); Bogatsky, V.; Danileksky, S.; Galkina, L. (TPO, VNIGRI, Ukhta (Russian Federation)) (and other)

1996-01-01

282

Nuevos gastrópodos del Pérmico inferior de la Formación Mojón de Hierro, provincia del Chubut, Argentina/ New Lower Permian gastropods from the Mojón de Hierro Formation, Chubut Province, Argentina  

Scientific Electronic Library Online (English)

Full Text Available Abstract in spanish Se describen nuevos gastrópodos del Pérmico inferior (Zona de Euphemites chubutensis-Palaeoneilo aff. concentrica) de la cuenca Tepuel-Genoa. El material corresponde a las localidades de Quebrada Honda y El Molle de la Formación Mojón de Hierro. El género Borestus Thomas (Pleurotomarioidea) es registrado por primera vez para Argentina con la nueva especie Borestus lunatus. También se propone un nuevo subgénero y nueva especie, Sinuitina (Spirilira) tenuis. El nuevo (more) subgénero se caracteriza por la presencia de ornamentación espiral, perfil de las vueltas subcordado y debilitamiento de la ornamentación colabral de la mitad exterior del flanco hacia el dorso. Abstract in english New gastropods from the Lower Permian (Euphemites chubutensis-Palaeoneilo aff. concentrica Zone) of the Tepuel-Genoa Basin are described. The material was recovered from the Mojón de Hierro Formation, at the Quebrada Honda and El Molle localities. The genus Borestus Thomas (Pleuroto-marioidea) is reported for the first time in Argentina with the new species Borestus lunatus. In addition, Sinuitina (Spirilira) tenuis nov. subgen. nov. sp. ( Bellerophontoidea) is proposed. (more) The new subgenus is characterized by spiral ornamentation, subcordate whorls in section, and a reduced collabral ornamentation on outer flanks and dorsum.

Pinilla, Karina; Sabattini, Nora; Hlebszevitsch, Julio

2007-06-01

283

Global coal gap between Permian-Triassic extinction and Middle Triassic recovery of peat-forming plants  

Energy Technology Data Exchange (ETDEWEB)

Early Triassic coals are unknown, and Middle Triassic coals are rare and thin. The Early Triassic coal gap began with extinction of peat-forming plants at the end of the Permian (ca. 250 Ma), with no coal known anywhere until Middle Triassic (243 Ma). Permian levels of plant diversity and peat thickness were not recovered until Late Triassic (230 Ma). Tectonic and climatic explanations for the coal gap fail because deposits of fluctuating sea levels and sedimentary facies and paleosols commonly found in coal-bearing sequences are present also in Early Triassic rocks. Nor do we favor explanations involving evolutionary advances in the effectiveness of fungal decomposers, insects or tetrapod herbivores, which became cosmopolitan and much reduced in diversity across the Permian-Triassic boundary. Instead, we favor explanations involving extinction of peat-forming plants at the Permian-Triassic boundary, followed by a hiatus of some 10 m.y. until newly evolved peat-forming plants developed tolerance to the acidic dysaerobic conditions of wetlands. This view is compatible not only with the paleobotanical record of extinction of swamp plants, but also with indications of a terminal Permian productivity crash from {delta}{sup 13}C{sub org} and total organic carbon of both nonmarine and shallow marine shales. 205 refs., 3 figs., 3 tabs.

Retallack, G.J. [Univ. of Oregon, Eugene, OR (United States); Veevers, J.J.; Morante, R. [Macquarie Univ., New South Wales (Australia)

1996-02-01

284

Paleomagnetic results from the Upper Permian of the eastern Qiangtang Terrane of Tibet and their tectonic implications  

Science.gov (United States)

Paleomagnetic samples were collected from red intercalations within the Upper Permian Tuoba Formation from the eastern Qiangtang Terrane of Tibet. Progressive thermal demagnetization has revealed a prefolding, possibly primary, characteristic remanent magnetization (ChRM), which yields a tilt-corrected mean direction ofD/I=25.2°6.7° (? 95 = 8.6°). The equatorial paleolatitude for the Qiangtang Terrane indicated by this result and the similarity of Late Permian fauna and flora shared by the Qiangtang Terrane and South China Block (SCB) suggest that the two terranes were in close proximity during the Late Permian. A Late Permian paleogeographic reconstruction involving the major terranes of the present-day East Asia is constructed, in which the Songpan-Garze Sea is surrounded by Laurasia, the North China Block (NCB), the SCB and the Qiangtang Terrane. The Permian development of the Songpan-Garze Sea appears to be related to the rifting of the Qiangtang Terrane off the SCB. Its Triassic evolution may resemble that of the Solomon Sea today in the southwestern Pacific.

Huang, Kainian; Opdyke, Neil D.; Peng, Xingjie; Li, Jiguang, Li

1992-06-01

285

Biostratigraphy and event stratigraphy in Iran around the Permian Triassic Boundary (PTB): Implications for the causes of the PTB biotic crisis  

Science.gov (United States)

The conodont succession and stratigraphic events around the Permian Triassic boundary (PTB) have been investigated in detail in the open sea deposits of Iran (Abadeh and Shahreza in central Iran, and Jolfa and Zal in northwestern Iran). This investigation produced a very detailed conodont zonation from the Clarkina nodosa Zone up to the Isarcicella isarcica Zone. All significant events have been accurately located and dated within this zonation, and the duration of most of these conodont zones has been calculated by cross-correlation with continental lake deposits that display obvious Milankovitch cyclicity. The unusually short duration of all conodont zones in the interval from the C. nodosa up to the Hindeodus parvus Zone indicates that there was persistent high ecological stress during this time interval. Most of the conodont zones can be accurately correlated with South China. In the interval from the C. hauschkei Zone to the H. parvus Zone, even correlation with the Arctic is possible. Within three thin stratigraphic intervals, the Changhsingian (Dorashamian) warm water conodont fauna of the C. subcarinata lineage is replaced by a cool water fauna with small H. typicalis, rare Merrillina sp., and cool water Clarkina that have very widely spaced denticles. The uppermost cool water fauna horizon comprises the lower C. zhangi Zone and can be accurately correlated with continental beds by recognition of a short reversed magnetozone below the long uppermost Permian lowermost Triassic normal magnetozone. In Iran and Transcaucasia, this short reversed zone comprises the upper C. changxingensis C. deflecta Zone and most of the C. zhangi Zone. Its top lies 50 cm below the top of the Paratirolites Limestone (s.s.) in the Dorasham 2 section, which is at the beginning of the upper quarter of the C. zhangi Zone. In the Germanic Basin, this short palaeomagnetic interval comprises the lower and the basal part of the upper Fulda Formation. On the Russian Platform, the Nedubrovo Formation belongs to this short reversed magnetic interval. In its upper part (corresponding to the top of the lower C. zhangi Zone, see above) there is a fallout of mafic tuffs from the Siberian Trap event that originated about 3000 km away in eruption centres in the Siberian Tungusska Basin. In the Germanic Basin and in Iran, this horizon contains volcanic microsphaerules. Thus, a direct correlation can be made between the immigration of a cool water fauna into the tropical realm and an exceptionally strong interval of explosive activity during the Siberian Trap volcanic episode. These faunal changes are the same as those found at the base of the Boundary Clay, suggesting that a short cooling event at this horizon also was due to intense volcanism. Additional influence by a bolide impact cannot be excluded. Most of the events in the interval from the C. nodosa up to the I. isarcica Zone (upper Changhsingian to middle Gangetian) in the Iranian sections can be also observed in other marine sections (e.g., in Meishan) and even in continental sections of the Germanic Basin. Of particular significance is the fact that, in the investigated Iranian sections, the PTB lies either in red sediments or in light grey sediments (as in Abadeh) that contain an ostracod fauna indicative of highly oxygenated bottom waters. Therefore, anoxia cannot be the reason for the PTB extinction event in this region, even though anoxia does cause locally or regionally elsewhere an overprint on the extinction event.

Kozur, H. W.

2007-01-01

286

Geologic evolution and hydrocarbon prospects in the Chotts Basin, Tunisia  

Energy Technology Data Exchange (ETDEWEB)

The Chotts Basin, running east-west across central Tunisia, is a complex Late Paleozoic to Mesozoic graben system with a sediment thickness reaching over 5000m. It covers an area of over 15,000 km{sup 2} but is underexplored. It has been drilled by only a few wells; several of which gave oil and gas shows. A number of oil and condensate fields lie immediately south. ETAP, the national oil company, has undertaken a detailed investigation of the basin, greatly improving our understanding of its evolution and prospectivity. The basin is floored by Lower Paleozoic sediments. These occur at shallow depth on the southern flank where they were affected by periodic contemporary tectonism. The succession includes Ordovician clastics with good reservoir potential and both Ordovician and uppermost Silurian source rocks. Locally, the latter unconformably overlie Ordovician reservoir sections. The basin developed into a major, east-west trending, intracratonic wrench basin during the late Permian. Carbonate facies dominate the southern shelf area and, although lithofacies distributions are poorly constrained, the existence of quality source rocks is a strong possibility. The graben complex was inverted and partly eroded prior to deposition of Upper Triassic volcanics and sandstones. The sandstones are a proven reservoir and several leads are identified. Substantial subsidence occurred in the northern part of the basin from the Middle Jurassic to Early Cretaceous. Jurassic carbonates provide numerous reservoir sections, while Callovian shales constitute a proven, mature source rock. Large fault- and fold- related traps were formed during latest Cretaceous to Paleocene and Mio-Pliocene orogeny; they provide promising objectives.

Johns, C. [Scott Pickford Group, Surrey (United Kingdom); Chine, A. [Entreprise Tunisienne d`Activites Petrolieres (ETAP), Tunis (Tunisia)

1995-08-01

287

Subsidence beneath a playa basin on the Southern High Plains, U. S. A. Evidence from shallow seismic data  

Energy Technology Data Exchange (ETDEWEB)

Shallow seismic data from Sevenmile Basin, a large ephemeral lake (playa) basin in the Texas Panhandle, reveal that subsidence has been an important agent in basin formation. Sevenmile Basin is 5.5 x 3.6 km across and 14 m deep and contains 20 m of lacustrine and eolian sediments that interfinger with the Quaternary Blackwater Draw Formation. Seismic reflection and refraction data were collected from the unlithified and variably saturated clastic sequence beneath Seven-mile Basin to investigate the geological history and hydrogeological framework of playa basins, which recharge the regionally important Ogallala aquifer. Three-layer velocity models provide good solutions for reversed refraction data. Near-surface p-wave velocities (layer 1) range from 349 to 505 m/s, layer 2 velocities range from 806 to 851 m/s, and layer 3 velocities range from 2,037 to 2,161 m/s. Shallow test holes and drillers' logs suggest that layer 1 is composed of playa and upper Blackwater Draw Formation deposits, layer 2 consists of lower Blackwater Draw Formation and upper Ogallala Formation deposits, and layer 3 represents a competent and partly saturated zone near the top of the Ogallala aquifer. Reflection sections show a middle Ogallala reflector, a reflector at the top of Permian or Triassic bedrock, and internal bedrock reflectors that indicate a structural low beneath Sevenmile Basin. Increasing relief with age, from 14 m at the surface to 70 m on the middle Ogallala reflector to 110 m at the base of the Ogallala, is interpreted as evidence of subsidence of underlying Permian evaporite-bearing strata before or during Ogallala deposition. 29 refs., 12 figs., 2 tabs.

Paine, J.G. (Univ. of Texas, Austin, TX (United States))

1994-02-01

288

Possible origins of Permian remagnetizations in Devonian and Carboniferous limestones from the Moroccan Anti-Atlas (Tafilalet) and Meseta  

Science.gov (United States)

Permian overprints have been recognized for several years in different regions of the Hercynian chain. This process seems to affect not only large internal parts, but also external zones of the chain. Devonian limestones sampled in the Tafilalet and Maider massifs near Erfoud and Msissi reveal a strong Permian component carried mainly by magnetite. Scanning Electron Microscope (SEM) and X-ray investigations were performed in order to unravel the origin of this magnetite. Permian remagnetizations are also present in Visean limestones from the Meseta. Isothermal Remanent Magnetization studies and SEM analysis of magnetic separates show that this magnetization is carried mainly by pyrrhotite which could be a result of oxidation of pre-existing pyrite.

Salmon, E.; Edel, J. B.; Pique, A.; Westphal, M.

1988-11-01

289

Size-frequency distributions along a latitudinal gradient in Middle Permian fusulinoideans.  

UK PubMed Central (United Kingdom)

Geographic gradients in body size within and among living species are commonly used to identify controls on the long-term evolution of organism size. However, the persistence of these gradients over evolutionary time remains largely unknown because ancient biogeographic variation in organism size is poorly documented. Middle Permian fusulinoidean foraminifera are ideal for investigating the temporal persistence of geographic gradients in organism size because they were diverse and abundant along a broad range of paleo-latitudes during this interval (~275-260 million years ago). In this study, we determined the sizes of Middle Permian fusulinoidean fossils from three different paleo-latitudinal zones in order to examine the relationship between the size of foraminifers and regional environment. We recovered the following results: keriothecal fusulinoideans are substantially larger than nonkeriothecal fusulinoideans; fusulinoideans from the equatorial zone are typically larger than those from the north and south transitional zones; neoschwagerinid specimens within a single species are generally larger in the equatorial zone than those in both transitional zones; and the nonkeriothecal fusulinoideans Staffellidae and Schubertellidae have smaller size in the north transitional zone. Fusulinoidean foraminifers differ from most other marine taxa in exhibiting larger sizes closer to the equator, contrary to Bergmann's rule. Meridional variation in seasonality, water temperature, nutrient availability, and carbonate saturation level are all likely to have favored or enabled larger sizes in equatorial regions. Temporal variation in atmospheric oxygen concentrations have been shown to account for temporal variation in fusulinoidean size during Carboniferous and Permian time, but oxygen availability appears unlikely to explain biogeographic variation in fusulinoidean sizes, because dissolved oxygen concentrations in seawater typically increase away from the equator due to declining seawater temperatures. Consequently, our findings highlight the fact that spatial gradients in organism size are not always controlled by the same factors that govern temporal trends within the same clade.

Zhang Y; Payne JL

2012-01-01

290

Chronostratigraphic assignment, based in Strontium isotopes ({sup 87} Sr/{sup 86} Sr) from the Andira Formation (Amazon Basin) and Cruzeiro do Sul Formation (Acre Basin), Brazil; Indicacao cronoestratigrafica, com base em isotopos de estroncio ({sup 87} Sr/{sup 86} Sr), das Formacoes Andira (Bacia do Amazonas) e Cruzeiro do Sul (Bacia do Acre)  

Energy Technology Data Exchange (ETDEWEB)

This paper presents some Sr isotope data ({sup 87} Sr/{sup 86} Sr ratios) from the Andira Formation (Amazon Basin) and Cruzeiro do Sul Formation (Acre Basin) in Northern Brazil. For the first one the analyzed materials were anhydrite found in the median portion of the stratigraphic unit. Limestones samples in the basal portion were the rocks studied in the second unit. The results suggest, respectively, the Sakmarian and Asselian/Sakmarian stages for their depositions, both in the Lower Permian. 14 refs., 4 figs., 2 tabs.

Rodrigues, Rene; Takaki, Tikae [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas; Soliani Junior, Enio [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Inst. de Geociencias; Sato, Kei; Kawashita, Koji [Sao Paulo Univ., SP (Brazil). Inst. de Geociencias

1997-06-01

291

Impact event at the Permian-Triassic boundary: evidence from extraterrestrial noble gases in fullerenes.  

UK PubMed Central (United Kingdom)

The Permian-Triassic boundary (PTB) event, which occurred about 251.4 million years ago, is marked by the most severe mass extinction in the geologic record. Recent studies of some PTB sites indicate that the extinctions occurred very abruptly, consistent with a catastrophic, possibly extraterrestrial, cause. Fullerenes (C60 to C200) from sediments at the PTB contain trapped helium and argon with isotope ratios similar to the planetary component of carbonaceous chondrites. These data imply that an impact event (asteroidal or cometary) accompanied the extinction, as was the case for the Cretaceous-Tertiary extinction event about 65 million years ago.

Becker L; Poreda RJ; Hunt AG; Bunch TE; Rampino M

2001-02-01

292

Configuration of the magnetic field and reconstruction of Pangaea in the Permian period.  

UK PubMed Central (United Kingdom)

The virtual geomagnetic poles of Laurasia and Gondwanaland in the Carboniferous and Permian periods diverge significantly when these continents are reassembled according to the fit calculated by Bullard et al. Two interpretations have been offered: Briden et al. explain these divergences by a magnetic field configuration very different from that of a geocentric axial dipole; Irving (and private communication), Van der Voo and French(4) suggest a different reconstruction and it is shown here that these two interpretations are not incompatible and that the first may help the second.

Westphal M

1977-05-01

293

Configuration of the magnetic field and reconstruction of Pangaea in the Permian period.  

Science.gov (United States)

The virtual geomagnetic poles of Laurasia and Gondwanaland in the Carboniferous and Permian periods diverge significantly when these continents are reassembled according to the fit calculated by Bullard et al. Two interpretations have been offered: Briden et al. explain these divergences by a magnetic field configuration very different from that of a geocentric axial dipole; Irving (and private communication), Van der Voo and French(4) suggest a different reconstruction and it is shown here that these two interpretations are not incompatible and that the first may help the second. PMID:16073416

Westphal, M

1977-05-12

294

Sponge assemblage of some Upper Permian reef limestones from Phrae province (Northern Thailand)  

Directory of Open Access Journals (Sweden)

Full Text Available The sponge fauna of uppermost Permian reef or reefal limestones of the Phrae province in northern Thailand include representatives of hexactinellida, sclerospongea,"sphinctozoans", and "inozoans". The "sphinctozoans" and "inozoans"are described in detail. Following taxa are new:"Sphinctozoans": Phraethalamia tubulara n. gen., n. sp., Ambithalamia pérmican. gen., n. sp."Inozoans": Bisiphonella tubulara n. sp., Solutossaspongia crassimuralis n.gen., n. sp.The genus name Belyaevaspongia nom. nov. is proposed for PolysiphonellaBelyaeva, 1991 (in Boiko et al., 1991), non Polysiphonella Russo, 1981.

Baba Senowbari-Daryan; Rucha Ingavat-Helmcke

1994-01-01

295

Impact event at the Permian-Triassic boundary: evidence from extraterrestrial noble gases in fullerenes.  

Science.gov (United States)

The Permian-Triassic boundary (PTB) event, which occurred about 251.4 million years ago, is marked by the most severe mass extinction in the geologic record. Recent studies of some PTB sites indicate that the extinctions occurred very abruptly, consistent with a catastrophic, possibly extraterrestrial, cause. Fullerenes (C60 to C200) from sediments at the PTB contain trapped helium and argon with isotope ratios similar to the planetary component of carbonaceous chondrites. These data imply that an impact event (asteroidal or cometary) accompanied the extinction, as was the case for the Cretaceous-Tertiary extinction event about 65 million years ago. PMID:11222855

Becker, L; Poreda, R J; Hunt, A G; Bunch, T E; Rampino, M

2001-02-23

296

Palynology and stratigraphy preliminary study and the perforation 313/1, lower Permian. Uruguay  

International Nuclear Information System (INIS)

The palynomorphs in the bore 313/1 of the Direccion Nacional de Mineria y Geologia are analyzed. Twenty three samples were processed, and only 9 were fertile. The lithologies correspond to sandstones of variable grain size, to mudstone and to diamictite, all of them assigned to the San Gregorio and Tres Islas Fms. The most abundant genera of sporare are essentially represented by monosaccate grains. Bisaccate and striated grains are very scare. The palynoflora is comparable with those studied in Brazil in the Fm Rio Bonito. Therefore, it is proposed that the sediments studied were deposited in the early Permian. (author)

1998-01-01

297

Geodynamic evolution of the Southeastern part of the Volga-Ural oil and gas bearing basin  

Energy Technology Data Exchange (ETDEWEB)

Voluminous informations on regional geology (DSS, geophysical and drilling data) of the southeastern part of the Volga Ural sedimentary basin in discussed to define its geodynamical setting. The first evidence of plate interaction is related to Riphean aulacogens, which are seen as aborted rifts. The morphology and types of structures formed during the Phanerozoic reflect the stress evolution along the eastern and southern boundaries of the Volga-Ural basin. The ancient stress regime there was connected with rifting, the drift of the East European plate from the southern to the northern hemisphere, and with the collision which caused the formation of the folded Urals and relict oceanic basin. The pre-Caspian depression is still identified by the shape of its sedimentary basins. The formation of present structural contours started in the late Permian, when the southeastern margin of the East European plate was blocked from all sides. In this model of basin evolution, problems of generation, migration and accumulation of hydrocarbons are also discussed. The location of oil and gas fields is mainly controlled by the history of basin development, reservoir rocks being mainly deposited during marine episodes. (authors). 6 refs., 12 figs.

Kazmin, L.L.; Gorelov, A.A.; Surovikov, Y.Y.; Khudnev, V.F. [AN SSSR, Moscow (Russian Federation). Inst. Geologii i Razvedki Goryuchikh Iskopaemykh

1996-12-01

298

Geology of coalbed methane reservoirs in the Southeast Qinshui Basin of China  

Energy Technology Data Exchange (ETDEWEB)

The No. 15 coal seam of the Pennsylvanian Taiyuan Formation and the No. 3 coal seam of the Permian Shanxi Formation in the Southeast Qinshui Basin are relatively thick (>3 m), laterally continuous, and are of anthracite rank (R{sub o}=2.2-4.5%). The depth of these coal seams is generally between 200 and 700 m. A tectonic-thermal event during the Jurassic to Cretaceous Yanshanian Orogeny controlled coalification and thermogenic hydrocarbon generation. Because the generation of late-stage bacterial gas, coalbed methane in the Southeast Qinshui Basin occupies two zones, which are the mixed thermogenic and late-stage bacterial gas zone near the basin margins, and the dominantly thermogenic gas zone in the structurally deep part of the basin. Basin hydrodynamics causes low gas content in the shallow subsurface (<20 m{sup 3}/t) and high gas content at the deep part of basin (>20 m{sup 3}/t). Because cleats are rare and are mostly filled with calcite, the permeability of the coalbed methane reservoir is controlled by shear fractures. The recharge and flow of groundwater not only control gas content, but also control reservoir pressure. Abnormally high pressure reservoir in the deep stagnant zone is a favorable area for coalbed methane exploration and development. The current coalbed methane wells are generally completed in the deep stagnant zone.

Su, Xianbo; Lin, Xiaoying [Henan Polytechnic University, Jiaozuo, Henan 454000 (China); Liu, Shaobo; Zhao, Mengjun; Song, Yan [Research Institute of Petroleum Exploration and Development, PetroChina, Beijing 10083 (China)

2005-06-22

299

Hydrocarbon potential of the Lamu basin of south-east Kenya  

Energy Technology Data Exchange (ETDEWEB)

The Lamu basin occupies the coastal onshore and offshore areas of south-east Kenya. This fault bounded basin formed as a result of the Paleozoic-early Mesozoic phase of rifting that developed at the onset of Gondwana dismemberment. The resultant graben was filled by Karroo (Permian-Early Jurassic) continental siliciclastic sediments. Carbonate deposits associated with the Tethyan sea invasion, dominate the Middle to Late Jurassic basin fill. Cessation of the relative motion between Madagascar and Africa in the Early Cretaceous, heralded passive margin development and deltaic sediment progradation until the Paleogene. Shallow seas transgressed the basin in the Miocene when another carbonate regime prevailed. The basin depositional history is characterized by pulses of transgressive and regressive cycles, bounded by tectonically enhanced unconformities dividing the total sedimentary succession into discrete megasequences. Source rock strata occur within Megasequence III (Paleogene) depositional cycle and were lowered into the oil window in Miocene time, when the coastal parts of the basin experienced the greatest amount of subsidence. The tectono-eustatic pulses of the Tertiary brought about source and reservoir strata into a spatial relationship in which hydrocarbons could be entrapped. A basement high on the continental shelf has potential for Karroo sandstone and Jurassic limestone reservoirs. Halokinesis of Middle Jurassic salt in Miocene time provides additional prospects in the offshore area. Paleogene deltaic sands occur in rotated listric fault blacks. A Miocene reef Play coincides with an Eocene source rock kitchen.

Nyagah, K.; Cloeter, J.J.; Maende, A. [National Oil Corp. of Kenya, Nairobi (Kenya)

1996-12-31

300

Laboratory testing of rock and salt samples for determination of specific gravity and total porosity of the Mansfield No. 1 Well (PD-4), Palo Duro Basin, Texas: unanalyzed data  

International Nuclear Information System (INIS)

[en] This report contains the specific gravity and total porosity determinations for rock and salt samples from Mansfield No. 1 Well of the Permian Basin. Laboratory test samples were measured for water content, apparent specific gravity, specific gravity of solids, total porosity and effective porosity. Specimen descriptions including specimen number, formation/group, and lithologic description as well as typical data sheets are included in the appendices. These data are preliminary. They have been neither analyzed nor evaluated. 1 table

1984-01-01

 
 
 
 
301

78 FR 16569 - Iowa Pacific Holdings, LLC, Permian Basin Railways, and San Luis & Rio Grande Railroad-Corporate...  

Science.gov (United States)

...operating as the Texas-New Mexico Railroad; (3) Chicago Terminal Railroad; (4) Mount Hood Railroad; (5) Rusk, Palestine & Pacific Railroad, LLC; (6) Santa Cruz and Monterey Bay Railway Company; and (7) West Texas & Lubbock...

2013-03-15

302

Permian and Triassic carbonate deposits in the drainage basin of the Toptal and Djankaindy Rivers in Central Pamirs (Kalaktash zone)  

International Nuclear Information System (INIS)

[en] Perm and triassic carbonate adjournment are drawn for the first time. Kaolin and bauxite breeds of these adjournments structure are certain. These breeds should be studied as raw material for manufacture of the aluminium industry

1993-01-01

303

Report of liquid permeability measurements on rock core samples from Mansfield No. 1 Well, Permian Basin project  

International Nuclear Information System (INIS)

[en] This report presents the results of the measurements on specimens from the Mansfield No. 1 Well, and it describes in some detail the apparatus and procedure used for the measurements to assist the reader in understanding how they were made. Where unusual specimen responses were encountered, the data reflecting the responses are presented and explanations offered. Finally, evaluations are made of both the results and the apparatus and procedure. 4 refs., 13 figs

1985-01-01

304

77 FR 49863 - Iowa Pacific Holdings, LLC and Permian Basin Railways-Continuance in Control Exemption-Santa Cruz...  

Science.gov (United States)

...Continuance in Control Exemption--Santa Cruz and Monterey Bay Railway Company Iowa Pacific...2) to continue in control of Santa Cruz and Monterey Bay Railway Company (SCMB...UP). The Line, known as the Santa Cruz Branch, extends from milepost...

2012-08-17

305

Petroliferous basins of India  

Energy Technology Data Exchange (ETDEWEB)

This special volume on petroliferous basins of India presents a summary of exploratory efforts in different basins, giving a cohesive picture incorporating historical perspective, review, and analysis of each basin in terms of its hydrocarbon potential. Arranged in order of defined categories of basins, the 15 papers cover extensively explored, partially explored, moderately explored, and essentially unexplored basins; a few papers overlapping these categories are structured to accommodate an overall assessment of the respective areas.

1983-11-01

306

Estudios sedimentológicos en los depósitos carboníferos y pérmicos del borde occidental de la puna/ Sedimentological study of Carboniferous and Permian deposits on the western edge of the Puna  

Scientific Electronic Library Online (English)

Full Text Available Abstract in spanish Se realizó el estudio de los depósitos carboníferos y pérmicos expuestos al sudoeste del Salar del Rincón, en el borde occidental de la Puna argentina; éstos comprenden a las capas rojas continentales de la Formación Cerro Oscuro (Carbonífero Superior) y a las calizas marinas de la Formación Arizaro (Pérmico Inferior). La columna estratigráfica analizada consta de 480 m de rocas clásticas y carbonáticas, con niveles volcaniclásticos intercalados. Los depósi (more) tos integran una estructura sinclinal de rumbo NNO, que se hunde hacia el NO. Los depósitos carbonífero-pérmicos fueron relevados en ambos flancos del sinclinal. En base a las características estratigráficas y sedimentológicas analizadas en las Formaciones Cerro Oscuro y Arizaro, se brindan nuevas interpretaciones paleoambientales: i. La secuencia grano y estratodecreciente que documenta la Formación Cerro Oscuro comprende, de base a techo, flujos de detritos acumulados en un sistema de abanico aluvial y tres ciclos o secuencias positivas, correspondientes a un sistema fluvial gravoso a arenoso tipo braided. ii. En las secciones analizadas, la relación entre las Formaciones Cerro Oscuro y Arizaro es una paraconformidad. iii. La Formación Arizaro comprende tres ciclos desarrollados en paleoambientes de plataforma marina silicoclástico - carbonática. Se describen características mineralógicas y petrográficas de las facies reconocidas y se incorpora un análisis de proveniencia, que sugiere la existencia de diferentes áreas de aporte. Se analiza la transgresión que documenta la Formación Arizaro y se la vincula con el evento de inundación global que provocaron los fenómenos de deglaciación ocurridos durante el Artinskiano-Kunguriano. Se discute la injerencia de procesos tectónicos y volcánicos que habrían afectado la cuenca durante su evolución. Abstract in english The study of Carboniferous - Permian deposits exposed in the south-west of Salar del Rincón, on the western edge of the Argentine Puna has been carried out. These deposits include the continental red beds of the Cerro Oscuro Formation (Upper Carboniferous) and the marine limestones of the Arizaro Formation (Lower to Middle Permian). The stratigraphic column analyzed consists of 480 m of clastic and carbonate rocks with interbedded volcaniclastic levels. The deposits inte (more) grate a synclinal structure of NNW-SSE trend, which pitches to the NW. The carboniferous-permian deposits were analized in both flanks of the syncline. Based on the stratigraphic and sedimentologic characteristics analyzed in the Cerro Oscuro and Arizaro Formations, new paleoenvironmental interpretations are given: i. The thinning and fining sequence that documents the Cerro Oscuro Formation includes, from base to top, debris flows accumulated in an alluvial fan system, and three cycles or minor positive sequences, corresponding to a sand-gravel braided fluvial system. ii. In the analyzed sections, the relationship between the Cerro Oscuro and Arizaro formations is a paraconformity. iii. The Arizaro Formation includes three cycles developed in a mixed carbonate-siliciclastic marine shelf paleoenvironment. Mineralogic and petrographic characteristics of the recognized facies are described and a provenance analysis wich suggests the existence of different source areas is included. The transgression that documents the Arizaro Formation is analyzed and it has been related with the global sea level rise event caused by deglaciation phenomena during the Artinskian-Kungurian time. The effect of tectonic and volcanic processes that would have affected the basin during their evolution is discussed.

Galli, Claudia Inés; Moya, María Cristina; Arnosio, Marcelo

2010-03-01

307

Estudios sedimentológicos en los depósitos carboníferos y pérmicos del borde occidental de la puna Sedimentological study of Carboniferous and Permian deposits on the western edge of the Puna  

Directory of Open Access Journals (Sweden)

Full Text Available Se realizó el estudio de los depósitos carboníferos y pérmicos expuestos al sudoeste del Salar del Rincón, en el borde occidental de la Puna argentina; éstos comprenden a las capas rojas continentales de la Formación Cerro Oscuro (Carbonífero Superior) y a las calizas marinas de la Formación Arizaro (Pérmico Inferior). La columna estratigráfica analizada consta de 480 m de rocas clásticas y carbonáticas, con niveles volcaniclásticos intercalados. Los depósitos integran una estructura sinclinal de rumbo NNO, que se hunde hacia el NO. Los depósitos carbonífero-pérmicos fueron relevados en ambos flancos del sinclinal. En base a las características estratigráficas y sedimentológicas analizadas en las Formaciones Cerro Oscuro y Arizaro, se brindan nuevas interpretaciones paleoambientales: i. La secuencia grano y estratodecreciente que documenta la Formación Cerro Oscuro comprende, de base a techo, flujos de detritos acumulados en un sistema de abanico aluvial y tres ciclos o secuencias positivas, correspondientes a un sistema fluvial gravoso a arenoso tipo braided. ii. En las secciones analizadas, la relación entre las Formaciones Cerro Oscuro y Arizaro es una paraconformidad. iii. La Formación Arizaro comprende tres ciclos desarrollados en paleoambientes de plataforma marina silicoclástico - carbonática. Se describen características mineralógicas y petrográficas de las facies reconocidas y se incorpora un análisis de proveniencia, que sugiere la existencia de diferentes áreas de aporte. Se analiza la transgresión que documenta la Formación Arizaro y se la vincula con el evento de inundación global que provocaron los fenómenos de deglaciación ocurridos durante el Artinskiano-Kunguriano. Se discute la injerencia de procesos tectónicos y volcánicos que habrían afectado la cuenca durante su evolución.The study of Carboniferous - Permian deposits exposed in the south-west of Salar del Rincón, on the western edge of the Argentine Puna has been carried out. These deposits include the continental red beds of the Cerro Oscuro Formation (Upper Carboniferous) and the marine limestones of the Arizaro Formation (Lower to Middle Permian). The stratigraphic column analyzed consists of 480 m of clastic and carbonate rocks with interbedded volcaniclastic levels. The deposits integrate a synclinal structure of NNW-SSE trend, which pitches to the NW. The carboniferous-permian deposits were analized in both flanks of the syncline. Based on the stratigraphic and sedimentologic characteristics analyzed in the Cerro Oscuro and Arizaro Formations, new paleoenvironmental interpretations are given: i. The thinning and fining sequence that documents the Cerro Oscuro Formation includes, from base to top, debris flows accumulated in an alluvial fan system, and three cycles or minor positive sequences, corresponding to a sand-gravel braided fluvial system. ii. In the analyzed sections, the relationship between the Cerro Oscuro and Arizaro formations is a paraconformity. iii. The Arizaro Formation includes three cycles developed in a mixed carbonate-siliciclastic marine shelf paleoenvironment. Mineralogic and petrographic characteristics of the recognized facies are described and a provenance analysis wich suggests the existence of different source areas is included. The transgression that documents the Arizaro Formation is analyzed and it has been related with the global sea level rise event caused by deglaciation phenomena during the Artinskian-Kungurian time. The effect of tectonic and volcanic processes that would have affected the basin during their evolution is discussed.

Claudia Inés Galli; María Cristina Moya; Marcelo Arnosio

2010-01-01

308

Tectonic evolution of the Colorado Basin, offshore Argentina, inferred from seismo-stratigraphy and depositional rates analysis  

Science.gov (United States)

Based on a dense 2D seismic reflection dataset and information from 8 exploration wells, we reinterpreted the stratigraphic evolution of the Colorado Basin. The basin is located on the continental shelf and slope within 50 to 2250 m of bathymetry. The total sediment fill can be up to 16,000 m. Seismic-to-well log correlations provide a chrono-stratigraphic framework for the interpreted seismic sequences. We show that the Colorado Basin records the development of a Permian pre-rift period, a Triassic/Jurassic to Early Cretaceous rift phase and a Lower Cretaceous to Tertiary drift phase. This passive margin represents the evolution of lithospheric extension from active rifting to the thermal subsidence/drift stage. Several Cretaceous to Cenozoic slumping episodes were identified and related to progradation of the sequences and sediment build-up in the slope, as well as to the development of seaward dipping extensional faults.

Loegering, M. J.; Anka, Z.; Autin, J.; di Primio, R.; Marchal, D.; Rodriguez, J. F.; Franke, D.; Vallejo, Eduardo

2013-09-01

309

Correlation of structural lineaments with oil discoveries in Potwar sub-basin, Pakistan  

International Nuclear Information System (INIS)

The Potwar sub-basin is located in the foothills of western Himalayas. It is developed as a result of continent collision between the Indian and Eurasian plates. This sub-basin is one of the major oil and gas producing-region of the country. Clastics of Cambrian, Permian, Jurassic, Paleocene, and carbonates of Permian, Paleocene, and Eocene are producing reservoir. Fractured and eocene carbonate reservoirs (Sakesar and Chorgali) are the main producing horizons in the region. Shale of infra-Cambrian-Cambrian and Paleocene are the main source rocks in the area. Interpretation of satellite data for lineament analysis coupled with stress models indicate that 63% of oil and gas fields fall along and 37% within 2-5 km radius of extensional lineaments and their corresponding open fractured zones developed due to various stress regimes. It is therefore suggested that exploration for hydrocarbon may be targeted in the strike extension of the mentioned lineaments in areas where optimum conditions for hydrocarbon generation exist. (author)

2001-01-01

310

Microbial response to limited nutrients in shallow water immediately after the end-Permian mass extinction.  

UK PubMed Central (United Kingdom)

Previous work indicates that a variety of microbes bloomed in the oceans after the end-Permian faunal mass extinction, but evidence is sporadically documented. Thus, the nature and geographic distribution of such microbes and their associations are unclear, addressed in this study using a series of biomarker groups. On the basis of microbial biomarker records of the 2-methylhopane index, evidence is presented for cyanobacterial blooms in both the western and eastern Tethys Sea and in both shallow and deep waters, after the mass extinction. The enhanced relative abundance of C(28) (expressed by the C(28) /C(29) ratio of) regular steranes suggests a bloom of prasinophyte algae occurred immediately after the end-Permian faunal extinction, comparable with those observed in some other mass extinctions in Phanerozoic. Significantly, cyanobacteria and prasinophyte algae show a synchronized onset of bloom in the shallow water Bulla section, north Italy, inferring for the first time their coupled response to the biotic crisis and the associated environmental conditions. However, in Meishan of Zhejiang Province in south China, the bloom declined earlier than in Bulla. The association of increased 2-methylhopane index with a negative shift in the nitrogen isotope composition infers a scenario of enhanced nitrogen fixation by cyanobacteria immediately after the faunal mass extinction. N(2) fixation by cyanobacteria is here interpreted to have provided prasinophyte algae with ammonium in nutrient-limited shallow waters, and thus caused their associated blooms.

Jia C; Huang J; Kershaw S; Luo G; Farabegoli E; Perri MC; Chen L; Bai X; Xie S

2012-01-01

311

Provenance evolution recorded by fine-grained Permian clastics, central Transantarctic Mountains  

Energy Technology Data Exchange (ETDEWEB)

During austral summer 1985-1986, the authors collected approximately 310 samples of fine-grained clastics from 24 measured sections in the Permian sequence of the central Transantarctic Mountains. The objective is to extract provenance and paleoclimatic information from these fine-grained sediments, using their mineral and chemical compositions as well as principles established by other workers. Because the Permian sequence in the central Transantarctic Mountains records the transition from a glacial regime (Pagoda Formation), through subaqueous clastic (deltaic) deposits (Mackellar Formation), to fluvial sequences (Fairchild Formation) with coals (Buckley Formation), such an examination promises to provide valuable insight into the timing and nature of this paleoenvironmental change. Samples that have experienced minimal post-depositional alteration have been recognized on the basis of five criteria: presence of kaolinite; low illite crystallinity index, indicating relatively abundant less-ordered illites; low illite polytype parameter, indicting relatively abundant less-ordered (i.e., low temperature) 1Md illites; low vitrinite reflectance value, indicating limited heating of organic components; and high organic carbon content.

Krissek, L.A.; Horner, T.C. (Ohio State Univ., Columbus (USA))

1987-01-01

312

Modeling the response to changes in tropospheric methane concentration: Application to the Permian-Triassic boundary  

Science.gov (United States)

We discuss model experiments valid for the Permian-Triassic boundary in which we explore the impact of changes in tropospheric methane concentration. For scenarios relevant to methane clathrate release, we consider surface methane concentration with values up to 5000 times its preindustrial concentration. We employ a comprehensive three-dimensional tropospheric-stratospheric model with chemistry that allows for the feedbacks between chemistry and climate. We show that stratospheric ozone starts collapsing for methane surface concentrations on the order of 1000 times their preindustrial concentration. At 5000 times, more than half of the total ozone column has disappeared. As a result a large rise (up to a factor of 7) in surface UV-B radiation is found. Other chemical consequences include a rise in CO and ozone surface concentrations; although becoming very large (up to 17 ppmv for CO), neither seems to reach lethal values according to present-day life forms. Finally, we show that tropospheric OH does not collapse for any of the scenarios; a corollary of this is a finite methane lifetime (45 years at the most). As a result, if methane were to increase significantly enough over a short period, the associated UV-B increase and/or deterioration of surface conditions could provide an explanation for the landmass extinction at the Permian-Triassic boundary.

Lamarque, J.-F.; Kiehl, J. T.; Shields, C. A.; Boville, B. A.; Kinnison, D. E.

2006-09-01

313

Rapid expansion of oceanic anoxia immediately before the end-Permian mass extinction.  

UK PubMed Central (United Kingdom)

Periods of oceanic anoxia have had a major influence on the evolutionary history of Earth and are often contemporaneous with mass extinction events. Changes in global (as opposed to local) redox conditions can be potentially evaluated using U system proxies. The intensity and timing of oceanic redox changes associated with the end-Permian extinction horizon (EH) were assessed from variations in (238)U/(235)U (?(238)U) and Th/U ratios in a carbonate section at Dawen in southern China. The EH is characterized by shifts toward lower ?(238)U values (from -0.37‰ to -0.65‰), indicative of an expansion of oceanic anoxia, and higher Th/U ratios (from 0.06 to 0.42), indicative of drawdown of U concentrations in seawater. Using a mass balance model, we estimate that this isotopic shift represents a sixfold increase in the flux of U to anoxic facies, implying a corresponding increase in the extent of oceanic anoxia. The intensification of oceanic anoxia coincided with, or slightly preceded, the EH and persisted for an interval of at least 40,000 to 50,000 y following the EH. These findings challenge previous hypotheses of an extended period of whole-ocean anoxia prior to the end-Permian extinction.

Brennecka GA; Herrmann AD; Algeo TJ; Anbar AD

2011-10-01

314

Characterization of bedded salt for storage caverns -- A case study from the Midland Basin, Texas  

Energy Technology Data Exchange (ETDEWEB)

The geometry of Permian bedding salt in the Midland Basin is a product of interaction between depositional facies and postdepositional modification by salt dissolution. Mapping high-frequency cycle patterns in cross section and map view using wireline logs documents the salt geometry. Geologically based interpretation of depositional and dissolution processes provides a powerful tool for mapping and geometry of salt to assess the suitability of sites for development of solution-mined storage caverns. In addition, this process-based description of salt geometry complements existing data about the evolution of one of the best-known sedimentary basins in the world, and can serve as a genetic model to assist in interpreting other salts.

Hovorka, Susan D.; Nava, Robin

2000-06-13

315

Regional well-log correlation in the New Mexico portion of the Delaware Basin  

International Nuclear Information System (INIS)

[en] Although well logs provide the most complete record of stratigraphy and structure in the northern Delaware Basin, regional interpretations of these logs generate problems of ambiguous lithologic signatures and on-hole anomalies. Interpretation must therefore be based on log-to-log correlation rather than on inferences from single logs. In this report, logs from 276 wells were used to make stratigraphic picks of Ochoan horizons (the Rustler, Salado, and Castile Formations) in the New Mexico portion of the Delaware Basin. Current log correlation suggests that: (1) the Castile is characterized by lateral thickening and thinning; (2) some Castile thinnings are of Permian age; (3) irregular topography in the Guadalupian Bell Canyon Formation may produce apparent structures in the overlying Ochoan units; and (4) extensive dissolution of the Salado is not apparent in the area of the Waste Isolation Pilot Project (WIPP) site. 13 refs., 37 figs

1985-01-01

316

Regional well-log correlation in the New Mexico portion of the Delaware Basin  

Energy Technology Data Exchange (ETDEWEB)

Although well logs provide the most complete record of stratigraphy and structure in the northern Delaware Basin, regional interpretations of these logs generate problems of ambiguous lithologic signatures and on-hole anomalies. Interpretation must therefore be based on log-to-log correlation rather than on inferences from single logs. In this report, logs from 276 wells were used to make stratigraphic picks of Ochoan horizons (the Rustler, Salado, and Castile Formations) in the New Mexico portion of the Delaware Basin. Current log correlation suggests that: (1) the Castile is characterized by lateral thickening and thinning; (2) some Castile thinnings are of Permian age; (3) irregular topography in the Guadalupian Bell Canyon Formation may produce apparent structures in the overlying Ochoan units; and (4) extensive dissolution of the Salado is not apparent in the area of the Waste Isolation Pilot Project (WIPP) site. 13 refs., 37 figs.

Borns, D.J.; Shaffer, S.E.

1985-09-01

317

The application of FAMM (Fluorescence Alteration of Multiple Macerals) analyses for evaluating rank of Parana Basin coals, Brazil  

Energy Technology Data Exchange (ETDEWEB)

Combining vitrinite reflectance (VR) and fluorescence alteration of multiple macerals (FAMM) analyses provide insights into the chemical nature of vitrinites (i.e., perhydrous vs. orthohydrous vs. subhydrous compositions) in Permian Gondwana coals of the Parana Basin, Brazil. The FAMM-derived equivalent VR (EqVR) values and relationships with VR can be determined according to calibration curves based largely on Permian Gondwana coals of eastern Australia.The analytical results indicate that vitrinites in the Parana Basin coals studied generally range from orthohydrous to perhydrous, with interpreted VR suppression ranging up to 0.2% absolute for the most perhydrous case. The EqVR values of the Santa Catarina coals, which range from about 0.85% to 0.95% differ from VR values by about 0.10-0.15% absolute, potentially having significant implications on coal utilization. The causes of vitrinite reflectance suppression in the Parana Basin coals are as yet poorly understood, but are likely to be related to a combination of factors.

Kalkreuth, W.; Cioccari, G.; Correa da Silva, Z.; Silva, M. [Instituto de Geociencias, Univ. Federal do Rio Grande do Sul, Av. Bento Goncalves, 9500, RS 91501-970 Porto Alegre (Brazil); Sherwood, N. [CSIRO Petroleum, P.O. Box 136, North Ryde, 1670 NSW (Australia); Zhong, N. [Department of Geoscience, University of Petroleum, Chang Ping, Beijing 102200 (China); Zufa, L. [School of Geography and Planning, Sun Yat-Sen University, Guangzhou 510275 (China)

2004-03-23

318

Facies and diagenesis of Triassic (Austrian alpine) and upper Permian (New Mexico-Texas) platform-margin carbonates: a comparison  

Energy Technology Data Exchange (ETDEWEB)

Platform-margin carbonates of the Austrian Middle and basal Upper Triassic (Carnian) (Wettersteinkalk) and Upper Permian (Capitan reef, Guadalupian) are similar in terms of facies development, biota, and syndepositional diagenetic fabrics. These similarities are noteworthy because of their occurrence across the Permian-Triassic boundary, and the fact that these carbonates are distinct from younger (Upper Triassic Dachsteinkalk) depositional systems. The Upper Permian and Middle to basal Upper Triassic were deposited as subdued rimmed platforms with component lagoonal, reef-flat, reef, and fore-reef facies belts. The reef facies appear to represent upper slope marginal mounds, and consist mainly of sponges, solitary corals, Tubiphytes, and various encrusting biota; typically, this facies is pervasively marine cemented. The reef-flat facies consist of similarly lithified biograin-stones deposited in high-energy wave-base zones along the platform margins. By contrast, steep rimmed platforms with massive framework coral buildups and relatively less syndepositional marine cements dominate in Upper Triassic units (e.g., Dachsteinkalk, Steinplatte reef). Proximal fore-reef beds in the Upper Permian and Middle to basal Upper Triassic are characterized by carbonate-clast debris cemented by coarse crystalline carbonate. The precipitation of this cement (grossoolith) may have occurred during early shallow burial of the fore-reef beds. Similar depositional and diagenetic facies are poorly developed in the Upper Triassic, instead being represented mainly by bedded micrites.

Mazzullo, S.J.; Lobitzer, H.

1988-02-01

319

ADVANCED OIL RECOVERY TECHNOLOGIES FOR IMPROVED RECOVERY FROM SLOPE BASIN CLASTIC RESERVOIRS, NASH DRAW BRUSHY CANYON POOL, EDDY COUNTY, NM  

Energy Technology Data Exchange (ETDEWEB)

The overall objective of this project is to demonstrate that a development program based on advanced reservoir management methods can significantly improve oil recovery at the Nash Draw Pool (NDP). The plan includes developing a control area using standard reservoir management techniques and comparing its performance to an area developed using advanced reservoir management methods. Specific goals are (1) to demonstrate that an advanced development drilling and pressure maintenance program can significantly improve oil recovery compared to existing technology applications and (2) to transfer these advanced methodologies to oil and gas producers in the Permian Basin and elsewhere throughout the U.S. oil and gas industry.

Mark B. Murphy

2002-12-31

320

Resultados paleomagnéticos preliminares en las sedimentitas neo-paleozoicas de la Formación El Imperial, bloque de San Rafael, Mendoza Preliminary paleomagnetic results from the Carboniferous-Permian El Imperial Formation sedimentary rocks in the San Rafael Block, Mendoza province  

Directory of Open Access Journals (Sweden)

Full Text Available Durante el Pérmico Temprano se desarrolló, en el margen sudoccidental del Gondwana, una extensa faja de deformación contraccional conocida con el nombre de cordón de las Gondwánides. En el extremo occidental de esta faja se instaló, durante el Carbonífero Tardío-Pérmico Temprano, una cuenca de antepaís cuyo relleno se encuentra representado por las sedimentitas de la Formación El Imperial aflorante en el bloque de San Rafael. Esta unidad presenta una sección superior que registra una inversión de las paleopendientes, la cual ha sido interpretada como la primera evidencia de la migración del frente de deformación hacia el antepaís. Se ha encarado un estudio paleomagnético de esta unidad en busca de elementos que permitan acotar la deformación en el tiempo para poder evaluar así el posible carácter diacrónico de la misma. Se presentan y discuten los primeros resultados paleomagnéticos obtenidos en sedimentitas del miembro inferior (Represa Agua del Toro) y superior (Puesto La Josefa) de la Formación El Imperial. Estas rocas son portadoras de magnetizaciones remanentes reversas portadas principalmente por hematita, de posible edad pérmica. Las posiciones paleopolares obtenidas en ambas localidades no coinciden con las esperadas según la edad de estas rocas, lo que se podría explicar o bien por que no se ha cancelado correctamente la variación secular, por rotaciones según ejes verticales en los bloques de las localidades de muestreo, o bien por la combinación de algunos o de todos estos factores.During the Early Permian an extensive deformation belt well-known as Gondwánides developed in the southwest Gondwana margin. A foreland basin has been settled during the Late Carboniferous - Early Permian in the western end of this strip, and is represented by the El Imperial Formation, which crops out in the San Rafael Block. The upper section of this unit records an inversion of the ancient slopes, which has been interpreted as the first evidence of the migration of the orogenic front towards the foreland. Therefore, a paleomagnetic study has been carried out on this unit, searching for elements that allow to constraint the deformation age to evaluate the possible diachronism of it. First paleomagnetic results obtained in El Imperial Formation, from the lower member in the Represa Agua del Toro and from the upper member in the Puesto La Josefa, are presented and discussed. These rocks have reverse magnetizations carried by hematite, of possible Permian age. Pole positions are discordant with the apparent polar wander path from South America. These differences could be explained because: secular variation was not properly averaged; rotations about vertical axes of the sampling localities; or the combination of these factors.

R.N. Tomezzoli; M.S. Japas

2006-01-01

 
 
 
 
321

Resultados paleomagnéticos preliminares en las sedimentitas neo-paleozoicas de la Formación El Imperial, bloque de San Rafael, Mendoza/ Preliminary paleomagnetic results from the Carboniferous-Permian El Imperial Formation sedimentary rocks in the San Rafael Block, Mendoza province  

Scientific Electronic Library Online (English)

Full Text Available Abstract in spanish Durante el Pérmico Temprano se desarrolló, en el margen sudoccidental del Gondwana, una extensa faja de deformación contraccional conocida con el nombre de cordón de las Gondwánides. En el extremo occidental de esta faja se instaló, durante el Carbonífero Tardío-Pérmico Temprano, una cuenca de antepaís cuyo relleno se encuentra representado por las sedimentitas de la Formación El Imperial aflorante en el bloque de San Rafael. Esta unidad presenta una sección s (more) uperior que registra una inversión de las paleopendientes, la cual ha sido interpretada como la primera evidencia de la migración del frente de deformación hacia el antepaís. Se ha encarado un estudio paleomagnético de esta unidad en busca de elementos que permitan acotar la deformación en el tiempo para poder evaluar así el posible carácter diacrónico de la misma. Se presentan y discuten los primeros resultados paleomagnéticos obtenidos en sedimentitas del miembro inferior (Represa Agua del Toro) y superior (Puesto La Josefa) de la Formación El Imperial. Estas rocas son portadoras de magnetizaciones remanentes reversas portadas principalmente por hematita, de posible edad pérmica. Las posiciones paleopolares obtenidas en ambas localidades no coinciden con las esperadas según la edad de estas rocas, lo que se podría explicar o bien por que no se ha cancelado correctamente la variación secular, por rotaciones según ejes verticales en los bloques de las localidades de muestreo, o bien por la combinación de algunos o de todos estos factores. Abstract in english During the Early Permian an extensive deformation belt well-known as Gondwánides developed in the southwest Gondwana margin. A foreland basin has been settled during the Late Carboniferous - Early Permian in the western end of this strip, and is represented by the El Imperial Formation, which crops out in the San Rafael Block. The upper section of this unit records an inversion of the ancient slopes, which has been interpreted as the first evidence of the migration of th (more) e orogenic front towards the foreland. Therefore, a paleomagnetic study has been carried out on this unit, searching for elements that allow to constraint the deformation age to evaluate the possible diachronism of it. First paleomagnetic results obtained in El Imperial Formation, from the lower member in the Represa Agua del Toro and from the upper member in the Puesto La Josefa, are presented and discussed. These rocks have reverse magnetizations carried by hematite, of possible Permian age. Pole positions are discordant with the apparent polar wander path from South America. These differences could be explained because: secular variation was not properly averaged; rotations about vertical axes of the sampling localities; or the combination of these factors.

Tomezzoli, R.N.; Japas, M.S.

2006-09-01

322

Termination of a continent-margin upwelling system at the Permian-Triassic boundary (Opal Creek, Alberta, Canada)  

Science.gov (United States)

Models of mass extinctions caused by greenhouse warming depend on the ability of warming to affect the oxygenation of the ocean, either through slowing circulation or changes in biological productivity and the organic carbon budget. Opal Creek, Alberta, Canada is a biostratigraphically continuous Permian-Triassic Boundary (PTB) section deposited in deep water on an outer shelf setting in the vast and understudied Panthalassic Ocean, along the western margin of Pangaea. The latest-Permian extinction is here represented as the disappearance of the previously dominant benthic fauna (siliceous sponges). On the basis of nitrogen and reduced sulfur isotopes as well as productivity-sensitive trace elements, the Middle Permian at Opal Creek is interpreted as a highly productive coastal upwelling zone where vigorous denitrification and sulfate reduction occurred in a mid-water oxygen minimum. Similar conditions appear to have continued into the latest Permian until the onset of a euxinic episode represented by a discrete pyrite bed and several trace element indicators of high productivity. This euxinic pulse is followed by the extinction of benthic fauna and a shift in nitrogen and sulfur isotopes to more normal marine values, suggesting the cessation of coastal upwelling and the consequent weakening of the mid-water oxygen minimum. The Lower Triassic appears to be a dysoxic, relatively unproductive environment with a bottom water oxygen minimum. Rhenium-osmium isotope systematics show a minimum of radiogenic Os near the main extinction event, which may be due to volcanic input, and increasingly radiogenic values approaching the PTB, possibly due to increased continental erosion. The Opal Creek system demonstrates that, while the biogeochemical crisis in the latest Permian was capable of impacting the coastal upwelling modality of ocean circulation, a transient increase in productivity likely drove the system toward euxinia and, ultimately, extinction.

Schoepfer, Shane D.; Henderson, Charles M.; Garrison, Geoffrey H.; Foriel, Julien; Ward, Peter D.; Selby, David; Hower, James C.; Algeo, Thomas J.; Shen, Yanan

2013-06-01

323

Chloride control and monitoring program in the Wichita River Basin, Texas, 1996-2009  

Science.gov (United States)

Water resources of the Wichita River Basin in north-central Texas are vital to the water users in Wichita Falls, Tex., and surrounding areas. The Wichita River Basin includes three major forks of the Wichita River upstream from Lake Kemp, approximately 50 miles southwest of Wichita Falls, Tex. The main stem of the Wichita River is formed by the confluence of the North Wichita River and Middle Fork Wichita River upstream from Truscott Brine Lake. The confluence of the South Wichita River with the Wichita River is northwest of Seymour, Tex. (fig. 1). Waters from the Wichita River Basin, which is part of the Red River Basin, are characterized by high concentrations of chloride and other salinity-related constituents from salt springs and seeps (hereinafter salt springs) in the upper reaches of the basin. These salt springs have their origins in the Permian Period when the Texas Panhandle and western Oklahoma areas were covered by a broad shallow sea. Over geologic time, evaporation of the shallow seas resulted in the formation of salt deposits, which today are part of the geologic formations underlying the area. Groundwater in these formations is characterized by high chloride concentrations from these salt deposits, and some of this groundwater is discharged by the salt springs into the Wichita River.

Haynie, M.M.; Burke, G.F.; Baldys, Stanley III

2011-01-01

324

Re-evaluation of Halle's fertile pteridosperms from the Permian floras of Shanxi Province, China  

UK PubMed Central (United Kingdom)

In 1927, T. G. Halle published an extensive synthesis of the Permian fossil plant assemblages from China's Shanxi Province that included five genera and species of seed plant that either had ovules in organic attachment or closely and repeatedly associated with foliage. These fertile pteridosperms were the subject of a later publication (1929) that provided additional information on each species, but since that time only Nystroemia pectiniformis Halle has been subjected to detailed investigation based on the original materials. Reinvestigation of the remaining four species has yielded additional examples and new information for each species, and has confirmed the pteridospermalean affinity for three of the four species. Alethopteris norinii Halle shows organic attachment of a pollen organ similar to Wittleseya (Newberry) Halle and is reinterpreted as a microsporangiate medullosan pteridosperm. Emplectopteris triangularis Halle and Sphenopteris tenuis (Schenk) Halle both bear numerous ovules attached directly to the leaf laminae, with Emplectopteris conforming with the gross-organisation of callistophytalean pteridosperms and S. tenuis being interpreted as a derived lagenostomalean pteridosperm. However, discovery of the counterpart to the key specimen of Pecopteris wongii Halle that Halle interpreted as bearing ovules demonstrates this species to be a sterile marattialean frond that agrees with its assignment to Pecopteris. In addition, two further specimens are demonstrated to be fertile organs of previously unknown pteridosperms; Norinosperma shanxiensis gen. et sp. nov. bears cardiocarpalean ovules abaxially on the proximal portions of the frond with ovules positioned directly on the veins of a leaf lamina; Norinotheca shanxiensis gen. et sp. nov. bears large pollen organs abaxially and singly on the vein of the leaf lamina. Collectively Halle's pteridosperms remain important today as they are some of the few specimens that actually demonstrate organic connection of fertile organs to foliage, helping to characterise the morphology and organisation of this seed plant group. These species also demonstrate the persistence of seed plant families and genera in the Permian of China that became regionally extinct at the end of the Carboniferous in Euramerica, and show that pteridosperms remained an important component of Permian as well as Carboniferous floras globally.

Seyfullah LeylaJ; Hilton Jason

2009-05-01

325

Classification of sedimentary basins  

Energy Technology Data Exchange (ETDEWEB)

Classification of sedimentary basins is akin to the purpose of investigation. Therefore, it varies a lot. Our chief interest is laid mainly upon the kind of sedimentary deposits that are relevant to the genetic history of sedimentary basins. To meet this end, we have first differentiated the temporal sequence relationship between sedimentation and basin-forming, and second have given due consideration to the genetic processes of sedimentary basins.

Ye, L.; Sun, S.

1980-07-01

326

Basin workshop Aarhus 1989  

Energy Technology Data Exchange (ETDEWEB)

Papers presented at the Basin Workshop held at the University of Aarhus on April 20-22, 1989 under the auspices of the Department of Earth Sciences (Geologisk Institut). The main subject was sedimentary basins and a wide range of geological topics was covered. These included regional and deep geology, stratigraphy, source rock and reservoir analysis and basin and hydrocarbon modelling. (AB).

Balling, N.; Bjoerslev Nielsen, O.; Korstgaard, J.A.; Nielsen, S.B. (eds.)

1990-01-01

327

The equisetalean genus Cruciaetheca nov. from the Lower Permian of Patagonia, Argentina.  

UK PubMed Central (United Kingdom)

The new genus Cruciaetheca (Equisetales, Sphenopsida) is described from the Río Genoa Formation, Lower Permian of Chubut Province, Argentina. Ramified, whorled vegetative axes terminally bearing leaf whorls of the Phyllotheca type characterize this genus; some last-order axes bear fertile internodes with whorls of cruciate sporangiophores between unmodified leaf whorls. We describe three species, Cruciaetheca patagonica (Feruglio) Cúneo et Escapa nov. comb., Cruciaetheca feruglioi Cúneo et Escapa nov. sp., and Cruciaetheca genoensis Cúneo et Escapa nov. sp., that are diagnosed from vegetative and reproductive features. The new material is compared with other Paleozoic equisetaleans from different geographical regions. We reevaluate the use of the genus Phyllotheca in light of finding Phyllotheca foliar whorls associated with completely distinct reproductive characters. The systematic position of Cruciaetheca is discussed as well as the significance of its cruciate sporangiophores and other characters.

Cuneo NR; Escapa I

2006-01-01

328

Silicification of trace fossils in carbonates; evidence from Permian Kaibab Formation, southwestern Utah  

Energy Technology Data Exchange (ETDEWEB)

Silicification in carbonates, particularly silicified trace fossils, has received relatively little previous study. Chert comprises a significant percentage of the upper Fossil Mountain Member of the Kaibab Formation, a Permian epicontinental limestone. Distribution and origin of this chert were studied from outcrops in southwestern Utah. The origin of much of this chert is believed to be as silicified Thalassinoides burrows. Field evidence for trace fossil silicification includes (1) silicified cylindrical tubes with Y-shaped branching patterns as well as hollow tubes, and (2) polygonal box-work patterns of tubes. In addition, brachiopods, bryozoans, and abundant specimens of the sponge Actinocelia maendrina Finks are also silicified. Recognition of silicified trace fossils in carbonates provides a different approach to the study of early diagenetic silica precipitation. These silicified trace fossils also represent new information on bioturbation in ancient carbonates, a subject that has, until recently, been relatively unstudied.

Whidden, K.J.; Bottjer, D.J.

1989-04-01

329

Control of sea-level change to coal accumulation in Carboniferous-Permian, north China  

Energy Technology Data Exchange (ETDEWEB)

According to the results of sequence stratigraphic research, the Carboniferous-Permian depositional formation in North China were formed in a second order sea-level change cycle, which includes 4 cycles in the third order and 26 cycles in the fourth order. Several large scale coal accumulations took place during the turning point between the fall and rise of the third order sea-level, locating at the top of highstand system tracts. The formation of thin coal seams was correlated to the fourth order sea-level change cycle and occurred at the top of the parasequences. The development of coal accumulation was controlled by the sea-level change cycle. The sea-level change supplied the potential accommodate space for the accumulation of organic materials. The developmental range of coal accumulation was controlled by the periodic range of sea-level change, which controlled the evolution of coal accumulation in time and space. 9 refs., 4 figs.

Chen, S. [Petroleum University of China (China). Resource Department

2000-10-01

330

Depositional environment of Upper Carboniferous – Lower Permian beds in the Karavanke Mountains (Southern Alps, Slovenia)  

Directory of Open Access Journals (Sweden)

Full Text Available Late Paleozoic rocks were studied in detail in the Dovžanova soteska section. The Upper Carboniferous sedimentary succession, correlated with upper part of Auernig and SchulterkofelFm. in the Carnic Alps, indicates cyclic clastic-carbonate deposition in a coastal to shallow marine ramp setting with strong influenceofcoarse-grainedfluvial-deltaicsilici-clastics from the hinterland, storm dominated regime of nearshore sediments, and offshore algal buildups. The Lower Permian sequence is developed differently from its time equivalentGrenzland Fm. and is subdivided into Dovžanova soteska Fm., Born Fm., and Rigelj beds. It is marked by the formation of a reef mound on the platform margin. Open-marine inner platform close to the marginal shoals represented the depositional environment of the mixed carbonate-siliciclastic sediments. Thus, a platform evolution from a ramp into a rimmed shelf is suggested.

Matevž Novak

2007-01-01

331

Pre-Alleghenian (Pennsylvanian-Permian) hydrocarbon emplacement along Ordovician Knox unconformity, eastern Tennessee  

Energy Technology Data Exchange (ETDEWEB)

Cores taken during exploration for Mississippi Valley-type lead and zinc ores in the Mascot-Jefferson City zinc district of eastern Tennessee commonly contain hydrocarbon residues in carbonate rocks of the Knox Group immediately below the Lower Ordovician Knox unconformity. The location and number of these residue-bearing strata reveal information about the Paleozoic history of hydrocarbon emplacement in the region. Contour maps, generated from nearly 800 holes covering more than 20 km/sup 2/, indicate that zones with elevated organic content in the uppermost 30 m of the Lower Ordovician Mascot Dolomite show a strong spatial correlation with Middle Ordovician paleotopographic highs. These same zones show no spatial association with present-day structural highs, which were formed during Pennsylvanian-Permian Alleghenian tectonism. This suggests that the physical entrapment of hydrocarbons migrating through the upper permeable units of the Mascot must have occurred prior to the principal tectonism of the Alleghenian orogeny. 7 figures, 1 table.

Haynes, F.M.; Kesler, S.E.

1989-03-01

332

The upper permian (Zechstein) tunstall reef of North East England: Palaeoecology and early diagenesis  

Science.gov (United States)

Detailed field studies and laboratory examination have identified the palaeocommunities of the Late Permian Tunstall Reef Complex of N.E. England, and have enabled accurate 3-dimensional diagrams to be constructed illustrating the palaeocommunity structure. The different palaeocommunities reflect the development of the reef through time, from reef-base coquine to lower reef core palaeocommunities, and then through space, in the laterally equivalent reef-flat, upper reef core, reef crest and fore-reef talus palaeocommunities, and the backreef patch reef palaeocommunity. An important factor in the formation of the Tunstall Reef was the precipitation of sea-floor cement. Aragonite particularly was an extensive and rapid precipitate in the reef-base coquina, as revealed in undolomitized limestones, and this type of cementation appears to have been widespread in other reef facies too, as judged by the rare occurrence of undolomitized limestones and by textures in the dolomites which can now be interpreted as relics of marine cements.

Hollingworth, Neville T. J.; Tucker, Maurice E.

333

Application of advanced reservoir characterization, simulation and production optimization strategies to maximize recovery in slope and basin clastic reservoirs, West Texas (Delaware Basin). Annual report  

Energy Technology Data Exchange (ETDEWEB)

The objective of this project is to demonstrate that detailed reservoir characterization of slope and basin clastic reservoirs in sandstones of the Delaware Mountain Group in the Delaware Basin of West Texas and New Mexico is a cost-effective way to recover a higher percentage of the original oil in place through strategic placement of infill wells and geologically based field development. This project involves reservoir characterization of two Late Permian slope and basin clastic reservoirs in the Delaware Basin, West Texas, followed by a field demonstration in one of the fields. The fields being investigated are Geraldine Ford and Ford West fields in Reeves and Culberson Counties, Texas. Project objectives are divided into two major phases, reservoir characterization and implementation. The objectives of the reservoir characterization phase of the project were to provide a detailed understanding of the architecture and heterogeneity of the two fields, the Ford Geraldine unit and Ford West field. Reservoir characterization utilized 3-D seismic data, high-resolution sequence stratigraphy, subsurface field studies, outcrop characterization, and other techniques. Once reservoir characterized was completed, a pilot area of approximately 1 mi{sup 2} at the northern end of the Ford Geraldine unit was chosen for reservoir simulation. This report summarizes the results of the second year of reservoir characterization.

Dutton, S.P.; Asquith, G.B.; Barton, M.D.; Cole, A.G.; Gogas, J.; Malik, M.A.; Clift, S.J.; Guzman, J.I.

1997-11-01

334

Regional focus: Victorian basins  

Energy Technology Data Exchange (ETDEWEB)

Victoria is the largest oil producing state in Australia. Exploration activity in 1994/95 has resulted in a number of exploration wells drilled in the Gippsland Basin, and the Otway Basin. This feature contains several articles on the geology and hydrocarbon potential of these basins together with the Murray Basin, the Portland Trough and Torquay Sub-basin. Production licenses for petroleum and exploration permits are listed, showing the tenement number, tenement holder, the area covered by the license and the date of expiration. Tables. figs.

Anon.

1995-10-01

335

Divergent/passive margin basins  

Energy Technology Data Exchange (ETDEWEB)

This book discusses the detailed geology of the four divergent margin basins and establishes a set of analog scenarios which can be used for future petroleum exploration. The divergent margin basins are the Campos basin of Brazil, the Gabon basin, the Niger delta, and the basins of the northwest shelf of Australia. These four petroleum basins present a wide range of stratigraphic sequences and structural styles that represent the diverse evolution of this large and important class of world petroleum basins.

Edwards, J.D. (Shell Oil Company (US)); Santogrossi, P.A. (Shell Offshore Inc. (US))

1989-01-01

336

Post-Carboniferous tectonics in the Anadarko Basin, Oklahoma: Evidence from side-looking radar imagery  

Science.gov (United States)

The Anadarko Basin is a west-northwest east-southeast elongated trough filled with 10+ km of Paleozoic sediments. Most models call for tectonic activity to end in Pennsylvanian time. NASA Shuttle Imaging Radar (SIR-A) has revealed a distinctive and very straight west-northwest striking lineament set extending virtually the entire length of the Anadarko Basin. The lineaments cut across the relatively flat-lying Permian units exposed at the surface. The character of these lineaments is seen most obviously as a tonal variation. Between the lineaments there is a poorly reflecting “gray” zone; better reflectors are located south and particularly north of the lineaments. Analysis of stream drainage and topography suggests that the area between the lineaments is low in the west and high in the east. Major streams, including the Washita and Little Washita rivers, appear to be controlled by the location of the lineaments. Subsurface data indicate that the lineaments may be the updip expression of a buried major fault system, the Mountain View fault. This fault is characterized as southerly dipping; recent COCORP data suggest a shallow dip (30° 40°). Two principal conclusions arise from this analysis: (1) the complex Mountain View fault system appears to extend southeast to join the Reagan, Sulphur, and/or Mill Creek faults of the Arbuckle Mountains, and (2) this fault system has been reactivated in Permian or more recent time. We infer that minor reactivation of the Pennsylvanian faults has resulted in a subdued surficial expression of buried structures that largely control the location of several oil fields in the Anadarko Basin.

Nielsen, K. C.; Stern, R. J.

1985-06-01

337

Impact of Zn-Pb mining in the Olkusz ore district on the Permian aquifer (SW Poland).  

UK PubMed Central (United Kingdom)

Long-term extensive mining of Zn-Pb ores in the Olkusz area resulted in significant changes of water table levels and chemical composition of water in all aquifers in this area. Within the Permian aquifer, hydrochemical type of water evolved in two general stages. Short-term effect was freshening in the zones of contact with overlying the Triassic limestones and dolomites. Long-term effect was a change in flow pattern and, as a consequence, an inflow of naturally altered and antropogenically contaminated water from the Triassic aquifer into the Permian complex. This was especially intensive in densely fissured and fault zones. As a result of all these processes, hydrochemical type of water shifted from multi-ion types with various combinations of ions towards higher shares of sulphates, calcium and magnesium.

Motyka J; Postawa A

2013-05-01

338

Impact of Zn-Pb mining in the Olkusz ore district on the Permian aquifer (SW Poland).  

Science.gov (United States)

Long-term extensive mining of Zn-Pb ores in the Olkusz area resulted in significant changes of water table levels and chemical composition of water in all aquifers in this area. Within the Permian aquifer, hydrochemical type of water evolved in two general stages. Short-term effect was freshening in the zones of contact with overlying the Triassic limestones and dolomites. Long-term effect was a change in flow pattern and, as a consequence, an inflow of naturally altered and antropogenically contaminated water from the Triassic aquifer into the Permian complex. This was especially intensive in densely fissured and fault zones. As a result of all these processes, hydrochemical type of water shifted from multi-ion types with various combinations of ions towards higher shares of sulphates, calcium and magnesium. PMID:23633000

Motyka, Jacek; Postawa, Adam

2013-05-01

339

Burial diagenesis in the Upper Devonian reef complexes of the Geikie Gorge region, Canning basin, Western Australia  

Energy Technology Data Exchange (ETDEWEB)

The Devonian carbonates of the Geikie Gorge region, Canning basin, have undergone a long and complex diagenetic history that began in Devonian seawater with extensive marine cementation of platform-margin lithologies. Devonian-Lower Carboniferous burial diagenesis was the most important porosity occluding episode because almost all primary porosity was destroyed by equant calcite cements during this interval. Dolomitization and consequent secondary porosity development also occurred during early burial diagenesis. The distribution and geochemistry of the major calcite cements and dolomite types are consistent with these phases having been precipitated from connate marine or basinal brines. Karstification and minor calcite cementation took place during late Carboniferous subaerial exposure. Minor calcite cementation occurred during Permian-Cenozoic burial, predominantly in secondary porosity within pervasively dolomitized lithologies. Karstification, dedolomitization, and calcite recrystallization took place in association with Cenozoic meteoric diagenesis. Secondary moldic and intercrystalline porosity within the completely dolomitized lithologies were the longest lived porosity types in the carbonates. Some secondary porosity escaped both Devonian-Carboniferous and Permian-Cenozoic burial cementation, probably due to a lack of nucleation sites for calcite cements within completely dolomitized lithologies.

Wallace, M.W. (Univ. of Tasmania, Hobart (Australia)); Kerans, C. (Univ. of Texas, Austin (United States)); Playford, P.E. (Geological Survey of Western Australia, East Perth (Australia)); McManus, A. (National Centre for Petroleum Geology and Geophysics, Adelaide, South Australia (Australia))

1991-06-01

340

An Introduction and Virtual Field Trip to the Permian Reef Complex, Guadalupe and Delaware Mountains, New Mexico-West Texas  

Science.gov (United States)

Dr. Peter Scholle, a professor of geology at New Mexico Tech, oversees this site showcasing the geology of the Permian reefs of West Texas and southeastern New Mexico. The Salado Formation, part of this sequence, has been in the spotlight lately because it contains the newly discovered, 250 million-year-old, salt-dwelling bacteria (see this week's Scout Report's In the News). The classic sedimentary sections of the Guadalupe and Delaware mountains have been well studied because of their magnificent exposures of Permian aged carbonate platform and slope deposits. Each year, geology students flock to the region to learn about sequence stratigraphy, sedimentology, and tectonic history, among other things. At this information-rich, well-illustrated site, everyone gets a chance to see and learn about these rocks. Sections of the virtual guidebook feature text with links to the bibliography, and color diagrams and photographs. The site is divided into the following sections: General Settings, Previous Studies, Structural History, Stratigraphic Setting and Nomenclature, Depositional Patterns, Diagenetic Patterns, Recent Models, Oil and Gas Production, and Field Trip and Safety Notes. Especially useful to those planning a field trip are road logs and field stop descriptions of road cuts between El Paso and Carlsbad, McKittrick Canyon, Walnut Canyon, and Dark Canyon-Sitting Bull Falls-Rocky Arroyo. Take a moment to discover the beauty and amazing geology of these classic Permian Reefs.

 
 
 
 
341

A new bolosaurid parareptile, Belebey chengi sp. nov., from the Middle Permian of China and its paleogeographic significance  

Science.gov (United States)

A new bolosaurid parareptile, Belebey chengi sp. nov., is described from Dashankou, Gansu Province, China, a Middle Permian locality which is known mostly for its therapsid fauna. The material consists of well-preserved mandibular and anterior skull remains and currently represents the largest and latest surviving member of Bolosauridae. Phylogenetic analysis of bolosaurid interrelationships, the first analysis of any clade of Early Permian parareptiles, indicates that the new taxon groups consistently with the other (Russian) members of the genus Belebey, and forms the sister clade to the genus Bolosaurus from North America. The Early Permian Eudibamus cursoris from Germany falls into the basal most position within Bolosauridae. Our analysis also shows that the split between the main bolosaurid lineages must have occurred near or before the Permo-Carboniferous boundary and that the paleo-equatorial region of Laurasia probably served as the center of origination for these parareptiles. A similar pattern can be found in other clades of Paleozoic amniotes, suggesting that this may be the general trend in early amniote evolution.

Müller, Johannes; Li, Jin-Ling; Reisz, Robert R.

2008-12-01

342

A new bolosaurid parareptile, Belebey chengi sp. nov., from the Middle Permian of China and its paleogeographic significance.  

UK PubMed Central (United Kingdom)

A new bolosaurid parareptile, Belebey chengi sp. nov., is described from Dashankou, Gansu Province, China, a Middle Permian locality which is known mostly for its therapsid fauna. The material consists of well-preserved mandibular and anterior skull remains and currently represents the largest and latest surviving member of Bolosauridae. Phylogenetic analysis of bolosaurid interrelationships, the first analysis of any clade of Early Permian parareptiles, indicates that the new taxon groups consistently with the other (Russian) members of the genus Belebey, and forms the sister clade to the genus Bolosaurus from North America. The Early Permian Eudibamus cursoris from Germany falls into the basal most position within Bolosauridae. Our analysis also shows that the split between the main bolosaurid lineages must have occurred near or before the Permo-Carboniferous boundary and that the paleo-equatorial region of Laurasia probably served as the center of origination for these parareptiles. A similar pattern can be found in other clades of Paleozoic amniotes, suggesting that this may be the general trend in early amniote evolution.

Müller J; Li JL; Reisz RR

2008-12-01

343

Massive volcanism at the Permian-Triassic boundary and its impact on the isotopic composition of the ocean and atmosphere  

DEFF Research Database (Denmark)

Bulk carbonate and conodonts from three Permian-Triassic (P-T) boundary sections at Guryul Ravine (Kashmir), Abadeh (central Iran) and Pufels/Bula/Bulla (Italy) were investigated for d13C and d18O. Carbon isotope data highlight environmental changes across the P-T boundary and show the following features: (1) a gradual decrease of 4‰ to more than 7‰ starting in the Late Permian (Changhsingian) C. bachmanni Zone, with two superimposed transient positive excursions in the C. meishanensis-H. praeparvus and the M. ultima-S. ? mostleri Zones; (2) two d13C minima, the first at the P-T boundary and a higher, occasionally double-minimum in the lower I. isarcica Zone. It is unlikely that the short-lived phenomena, such as a breakdown in biological productivity due to catastrophic mass extinction, a sudden release of oceanic methane hydrates or meteorite impact(s), could have been the main control on the latest Permian carbon isotope curve because of its prolonged (0.5 Ma) duration, gradual decrease and the existenceof a >1‰ positive shift at the main extinction horizon. The P-T boundary d13C trend matches in time and magnitude the eruption of the Siberian Traps and other contemporaneous volcanism, suggesting that volcanogenic effects, such as outgassed CO2 from volcanism and, even more, thermal metamorphism of organic-rich sediments, as the likely cause of the negative trend.

Korte, Christoph; Pande, P.

2010-01-01

344

The armoured dissorophid Cacops from the Early Permian of Oklahoma and the exploitation of the terrestrial realm by amphibians.  

UK PubMed Central (United Kingdom)

Cacops, one of the most distinctive Paleozoic amphibians, is part of a clade of dissorophoid temnospondyls that diversified in the equatorial region of Pangea during the Late Carboniferous and Early Permian, persisting into the Late Permian in Central Russia and China. Dissorophids were a successful group of fully terrestrial, often spectacularly armoured predators, the only amphibians apparently able to coexist with amniotes when the latter started to dominate terrestrial ecosystems. In this paper, we describe excellent new skulls from the Early Permian of Oklahoma attributed to Cacops, Cacops morrisi sp. nov. and provide for the first time detailed information about this iconic dissorophid. These specimens show anatomical and ontogenetic features that will impact on future studies on the evolution of terrestriality in tetrapods. For example, the large, posteriorly closed tympanic embayment has fine striations on an otherwise smooth surface, documenting the oldest known clear evidence for the presence of a tympanic membrane in the fossil record, a structure that is used for hearing airborne sound in extant tetrapods. The skull of C. morrisi also has several features associated with predatory behaviour, indicating that this dissorophid may have been one of the top terrestrial predators of its time.

Reisz RR; Schoch RR; Anderson JS

2009-07-01

345

Stable carbon and oxygen isotope shifts in Permian seas of West Spitsbergen-Global change or diagenetic artifact?  

Science.gov (United States)

We performed petrographic, cathodoluminescence, electron-microprobe, and isotopic analyses of brachiopod shells from the Permian Kapp Starostin Formation in West Spitsbergen to reevaluate the >9‰ negative shift in ?13C and ?18O values reported in 1989 by M. Gruszczynski, S. Halas, A. Hoffman, and K. Malkowski. The ?13C and ?18O values within shells typically decrease with increasing luminescence, indicating diagenesis. Nonluminescent (NL) shell ?13C and ?18O values are 4.3‰ and 6.2‰ higher, respectively, than those of associated cements and matrix. For the same stratigraphic interval, ?13C and ?18O values of the NL shells are equal to, or substantially greater than, those reported by Gruszczynski et al. For the interval where those authors saw a 10‰ ?13C shift, our mostly NL Spiriferella polaris shells only yield a 1.5‰ shift. Gruszczynski et al. reported a 9‰ ?18O shift, whereas we observe almost none. Our results strongly suggest that the >9‰ isotopic shifts reported in Gruszczynski et al. are diagenetic artifacts. On the other hand, their Kazanian-Tatarian ?13C maximum of 7.5‰ is substantiated by our data. This Late Permian 13C maximum represents the highest spiriferid brachiopod ?13C values in the Phanerozoic and, within stratigraphic uncertainty, correlates with the whole-rock ?13C maximum in East Greenland and northwestern Europe. The ?13C shift may reflect changes in global storage of organic carbon indicated by coal-volume changes in the Late Permian.

Mii, Horng-Sheng; Grossman, Ethan L.; Yancey, Thomas E.

1997-03-01

346

Stable-isotope geochemistry of groundwaters in the Delaware Basin of southeastern New Mexico  

International Nuclear Information System (INIS)

18O/16O and D/H ratio measurements have been made on groundwaters sampled from the Rustler Formation (Ochoan, Permian) and related rocks in the northern Delaware Basin of southeastern New Mexico. Most confined Rustler waters at the Waste Isolation Pilot Plant (WIPP) site and to the west in Nash Draw and confined waters from the Capitan limestone constitute one population in ?D/?18O space, while unconfined groundwaters inferred to originate as modern surface recharge to alluvium, sandstones in the Ogallala Formation, the near-surface Rustler in southwestern Nash Draw, and the Capitan vadose zone in the Guadalupe Mountains (Carlsbad Caverns) constitute a distinctly different population; the two do not overlap. A likely explanation for this distinction is that meteoric recharge to most of the Rustler and Capitan took place in the geologic past under climatic conditions significantly different from the present. Available tritium and radiocarbon data are consistent with this hypothesis, and the apparent age of confined groundwaters is in excess of 12,000 radiocarbon years, suggesting that recharge took place under wetter conditions in the late Pleistocene. Processes governing recharge in the Delaware Basin are significantly different from those in the nearby Roswell Artesian Basin, but may be similar to those previously described for the Albuquerque (New Mexico) and Murray (South Australia) Basins. 133 refs

1987-01-01

347

Waterford Formation in the south-eastern Karoo: Implications for basin development  

Directory of Open Access Journals (Sweden)

Full Text Available Extensive research on the rocks of the Karoo Supergroup has shown that this sequence, which contains an unsurpassed record of Permian–Jurassic tetrapods, records a largely unbroken stratigraphic succession from 300 Ma to 180 Ma. This Gondwanan succession was deposited in a changing environmental setting reflecting glacial marine through deltaic to fluvial and aeolian desert conditions. The contact between the Ecca and Beaufort Groups (at the top of the Waterford Formation of the Ecca Group) in the southern and western Karoo represents a change in depositional environment from a subaqueous to a subaerial delta plain. By contrast, the Waterford Formation has not yet been recognised in the south-eastern Karoo Basin, which might imply that a major unconformity is present between the Fort Brown Formation of the Ecca Group, deposited in a prodelta environment, and the overlying fluvially deposited Koonap Formation of the Beaufort Group. From careful documentation of lithofacies and sedimentological data, it can be demonstrated that the Waterford Formation is indeed present in the south-eastern part of the basin and that no major unconformity is present – a fact that has implications for the mapping of Karoo rocks in the Eastern Cape Province of South Africa, for understanding the depositional environment of ’reptilian‘ fossils from the lowermost Beaufort in this part of the Karoo basin, and for basin development models.

Bruce S. Rubidge; P. John Hancox; Richard Mason

2012-01-01

348

Waterford Formation in the south-eastern Karoo: Implications for basin development  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english Extensive research on the rocks of the Karoo Supergroup has shown that this sequence, which contains an unsurpassed record of Permian-Jurassic tetrapods, records a largely unbroken stratigraphic succession from 300 Ma to 180 Ma. This Gondwanan succession was deposited in a changing environmental setting reflecting glacial marine through deltaic to fluvial and aeolian desert conditions. The contact between the Ecca and Beaufort Groups (at the top of the Waterford Formation (more) of the Ecca Group) in the southern and western Karoo represents a change in depositional environment from a subaqueous to a subaerial delta plain. By contrast, the Waterford Formation has not yet been recognised in the south-eastern Karoo Basin, which might imply that a major unconformity is present between the Fort Brown Formation of the Ecca Group, deposited in a prodelta environment, and the overlying fluvially deposited Koonap Formation of the Beaufort Group. From careful documentation of lithofacies and sedimentological data, it can be demonstrated that the Waterford Formation is indeed present in the south-eastern part of the basin and that no major unconformity is present - a fact that has implications for the mapping of Karoo rocks in the Eastern Cape Province of South Africa, for understanding the depositional environment of 'reptilian' fossils from the lowermost Beaufort in this part of the Karoo basin, and for basin development models.

Rubidge, Bruce S; Hancox, P. John; Mason, Richard

2012-01-01