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1

Permian Basin as a radioactive waste repository  

Energy Technology Data Exchange (ETDEWEB)

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.

Smith, J.W.

1975-11-02

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

Exploratory shaft conceptual design report: Permian Basin  

International Nuclear Information System (INIS)

This conceptual design report summarizes the conceptualized design for an exploratory shaft facility at a representative site in the Permian Basin locatd in the western part of Texas. Conceptualized designs for other possible locations (Paradox Basin in Utah and Gulf Interior Region salt domes in Louisiana and Mississippi) are summarized in separate reports. The purpose of the exploratory shaft facility is to provide access to the reference repository horizon to permit in situ testing of the salt. The in situ testing is necessary to verify repository salt design parameters, evaluate isotropy and homogeneity of the salt, and provide a demonstration of the constructability and confirmation of the design to gain access to the repository. The fundamental purpose of this conceptual design report is to assure the feasibility of the exploratory shaft project and to develop a reliable cost estimate and realistic schedule. Because a site has not been selected and site-specific subsurface data are not available, it has been necessary to make certain assumptions in order to develop a conceptual design for an exploratory shaft facility in salt. As more definitive information becomes available to support the design process, adjustments in the projected schedule and estimated costs will be required

1983-01-01

4

Thermal Conductivity of Permian Basin Bedded Salt at Elevated Pressure.  

Science.gov (United States)

Measurements of thermal conductivity were made on five core samples of bedded rock salt from the Permian Basin in Texas. The sample size was 100 mm in diameter by 250 mm in length. Measurements were conducted under confining pressures ranging from 3.8 to ...

W. B. Durham C. O. Boro J. M. Beiriger

1984-01-01

5

Thermal conductivity of Permian Basin embedded salt at elevated pressure  

International Nuclear Information System (INIS)

The authors report on the results of measurements of thermal conductivity made on five core samples of bedded rock salt from the Permian Basin in Texas. This work was done in line with the premise that rock salt formations are among the leading contenders as sites for nuclear waste disposal

1985-01-01

6

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

7

The Central European Permian Basins; Rheological and structural controls on basin history and on inter-basin connectivity  

Science.gov (United States)

We analyse the relative importance of the major crustal-scale fault zones and crustal architecture in controlling basin formation, deformation and the structural connections between basins. The North and South Permian Basins of Central Europe are usually defined by the extend of Rotliegend sedimentary and volcanic units and not by a common tectonic origin or development. Instead, the sub-basins that together form the Permian Basins are each controlled by different structural and/or rheological controls that are inherited from Early Paleozoïc and older geodynamic processes, they are even located in different crustal/lithospheric domains. The North Permian basin is located on Baltic crust that was thinned during Late Proterozoïc - Early Paleozoïc times. South of the Thor suture, the South Permian basin and its sub-basins are located on Avalonian crust (Southern North Sea and North German Basins) and on the transition of East European cratonic and Avalonian crust (Polish Through). The size of crustal domains and of the faults that govern basin formation requires a regional-scale to assess their impact on basins and sub-basins. In the case of the Permian Basins this encompasses East Avalonia and surroundings, roughly speaking the area north of the Variscan Rheïc suture, east of the Atlantic and southwest of the Teisseyre-Tornquist line. This approach sheds light on the effects of long lived differences in crustal fabric which are responsible for spatial heterogeneity in stress and strain magnitudes and zonations of fracturing, burial history and temperature history. The focus on understanding the geomechanical control of large crustal-scale fault structures will provide the constraints and geometrical and compositional input for local models of stress and strain. Considering their fundamentally different structural and rheological controls, the Permian (sub)basins have a remarkably common history of subsidence and inversion, suggesting a more or less continuous link between them. Post-Variscan, Late Carboniferous-Early Permian wrench tectonics is the oldest and main identified cause for regional basin formation in Central Europe. This relatively short-lived tectonic regime cannot explain the observed common history of subsidence of the Permian Basins during the 200 My that followed. Our analysis demonstrates that transfer faults that both follow and cross rheological transitions and inherited fault zones continued to be active after the early Permian. We therefore suggests that crustal-scale transfer faults may be the missing link that explains the common subsidence history of basins with a fundamentally different crustal architecture and structural history.

Smit, Jeroen; Van Wees, Jan-Diederik; Cloetingh, Sierd

2014-05-01

8

Upper Permian lacustrine oil shales, southern Junggar basin, northwest China  

Energy Technology Data Exchange (ETDEWEB)

Upper Permian organic-rich lacustrine mudstones (oil shales) that crop out in the southern Junggar basin rank among the richest and thickest petroleum source rock intervals in the world, with maximum TOC values reaching 34% and Rock-Eval pyrolytic yields (S[sub 2]) up to 200 kg HC/t rock. Lacustrine sedimentary facies define an overall transgressive-regressive cycle of approximately 2000 m gross thickness, which includes approximately 800 m of source rocks averaging 4.1% TOC and 26.2 kg HC/t rock. Basinal facies comprise silicic, organic-rich, laminated lacustrine mudstones and interbedded siltstones; organic matter contained in the mudstones ranges in composition from type I to type III. Basinal facies were deposited in a deep, oxygen-deficient, stratified lake. Lake-margin facies consist of nonlaminated siliciclastic mudstones, rippled dolomitic silstones and sandstones, and minor limestones. Maximum TOC values are approximately 6%. Desiccation cracks are common in the marginal facies, but evaporite minerals are rare or absent. Biomarker correlation parameters measured from rock extracts exhibit significant stratigraphic variability, but strongly support the hypothesis that Upper Permian lacustrine oil shales charge the giant Karamay field in the northwestern Junggar basin. Karamay oils are characterized by high relative abundances of [beta]-carotane. This characteristic is restricted to desiccated facies in the outcrop sections, however. We therefore propose that an abundance of [beta]-carotane indicates elevated environmental salinities during deposition of the oil shales. 16 figs., 9 tabs.

Carroll, A.R.; Brassell, S.C.; Graham, S.A. (Stanford Univ., CA (United States))

1992-12-01

9

Thermal Properties of Permian Basin Evaporites to 493 K Temperature and 30 MPa Confining Pressure.  

Science.gov (United States)

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 rangin...

W. B. Durham H. C. Heard C. O. Boro K. T. Keller W. E. Ralph

1987-01-01

10

Thermal Properties of Permian Basin Evaporites to 493 K and 30 MPa Confining Pressure.  

Science.gov (United States)

Laboratory measurements have been made of the thermal conductivity and diffusivity of four rock salts, two anhydrites, and two dolomites bordering the Cycle 4 and Cycle 5 bedded salt formations in the Permian Basin in Deaf Smith County, Texas. Measurement...

W. B. Durham H. C. Heard C. O. Boro K. T. Keller W. E. Ralph

1987-01-01

11

The Collie transtensional extension Basin: a starting point for Permian Gondwana correlation  

Energy Technology Data Exchange (ETDEWEB)

A sequence from Asselian to approximately Ufimian is preserved in the Collie Basin by post-depositional extensional faulting. It is proposed that many Indian, African and Antarctic Permian basins result from the same style of extensional tectonics and contain similar Permian sequences. The Collie Basin sequence contains ten palynological zones that are extrapolated into the Perth and Carnarvon basins. Tentative correlations are made with comparable Gondwana coalfields in India and southern Africa, based on published palynomorph range charts, and allow speculation on coeval depositional and palaeoclimatic regimes. 20 refs., 4 figs.

Le Blanc Smith, G.; Backhouse, J. [CSIRO, Kenmore, Qld. (Australia). Exploration & Mining Division

1996-08-01

12

Evolution of Permian evaporite basin in Texas panhandle  

Energy Technology Data Exchange (ETDEWEB)

Permian (Leonardian to Ochoan) evaporites in the Texas Panhandle were deposited in a range of marine shelf to supratidal environments along an arid coastline. Carbonates in these strata generally were deposited in inner shelf systems and include subtidal to supratidal facies. Landward of shelf environments, evaporites were deposited in brine pans and salt flats. Brine-pan facies are laminated anhydrite and banded salt that formed in shallow, hypersaline water such as restricted lagoons or supratidal salines. Salt-flat facies are mainly chaotic mixtures of mudstone and halite possibly formed by salt deposition on and within mud flats that bordered brine pans, or in brine-soaked mud-flat depressions. Periodically, mud flats built across the evaporite systems and were supplied with red terrestrial clastics, mainly mud and silt. These facies occur together in at least three different types of lithogenetic units. Strata in the Clear Fork Group (Leonardian) are considered deposits of a coastal evaporite basin that was progressively filled by terrestrial clastics. These rocks exhibit regressive cycles of brine-pan, salt-flat, and mud-flat facies. In contrast, San Andres strata (Guadalupian) were deposited in a broad marine embayment with persistent brine-pan conditions, and contain cycles of inner shelf and brine-pan facies. Post-San Andres strata (late Guadalupian and Ochoan) were deposited in the inner reaches of a broad interior salt basin and are composed mainly of mud-flat, salt-flat, and halite-rich brine-pan facies. 20 figs., 2 tabs.

Presley, M.W. (Univ. of Texas, Austin (USA))

1987-02-01

13

New Middle Permian palaeopteran insects from Lodève Basin in southern France (Ephemeroptera, Diaphanopterodea, Megasecoptera).  

Science.gov (United States)

Three new palaeopteran insects are described from the Middle Permian (Guadalupian) of Salagou Formation in the Lodève Basin (South of France), viz. the diaphanopterodean Alexrasnitsyniidaefam. n., based on Alexrasnitsynia permianagen. etsp. n., the ParelmoidaePermelmoa magnificagen. etsp. n., and Lodevohymen lapeyrieigen. etsp. n. (in Megasecoptera or Diaphanopterodea, family undetermined). In addition the first record of mayflies attributed to family Syntonopteridae (Ephemeroptera) is reported. These new fossils clearly demonstrate that the present knowledge of the Permian insects remains very incomplete. They also confirm that the Lodève entomofauna was highly diverse providing links to other Permian localities and also rather unique, with several families still not recorded in other contemporaneous outcrops. PMID:22259265

Prokop, Jakub; Nel, André

2011-01-01

14

Tectonic controls on Upper Permian lacustrine oil shales in the Junggar basin, NW China  

Energy Technology Data Exchange (ETDEWEB)

Collision of the Tarim craton with the southern margin of Asia during the Late Carboniferous-Early Permian resulted in uplift of an ancestral Tian Shan range and geographic isolation of the previously marine Junggar basin. Dramatic shifts from marine to nonmarine sedimentation took place in both the southern Junggar and northern Tarim basins during the Permina. Paleocurrent analysis indicate that by the Late Permian, coarse-grained sediments in both basins were being supplied predominantly from the area of the Tian Shan. During the Late Permian, the southern Junggar received in excess of 5,000 m of nonmarine sediments, including approximately 1,000 m of laminated, highly organic-rich lacustrine mudstones (oil shales). These deposits commonly have TOCs of 20-30%, and Rock-Eval pyrolitic yields reaching 2,000 mg/g, ranking them among the most prolific petroleum source rocks in the world. Based on a comparison of the distribution of steranes and extended tricyclic terpanes, these Upper Permian oil shales appear to be the primary source of oils in the giant Karamay field in the northwestern Junggar basin. Ancestral uplift of the Tian Shan thus produced a complex tectono-hydrologic partitioning of the Late Permina Junggar basin, which exerted a strong influence on the character of petroleum source rocks deposited within the basin.

Carroll, A.R.; Brassell, S.C.; Graham, S.A. (Stanford Univ., CA (United States))

1991-03-01

15

Geology and Permian coal resources of the Irwin Terrace, Perth Basin, Western Australia  

Energy Technology Data Exchange (ETDEWEB)

Potentially economic coal seams of the Permian Irwin River Coalfield cover approximately 170 kms of the Irwin Terrace on the east flank of the north Perth Basin. Mapping, drilling and gravity interpretation reveal outcropping coals that plunge to 400 m in a weakly folded half graben that strikes north-northwest. This post-depositional extensional structure contains an interpreted 1700 m of generally southeasterly dipping permian siliciclastic rocks preserved as a consequence of left-lateral shear in transtensional setting. Refined Permian rock stratigraphy is integrated with biostratigraphic palynomorph zones. Sediment ages span Carboniferous to Early Tatarian in the Late Permian. The coals are Aktastinian and correlate with the basal coal beds in the Collie Basin, south Perth Basin, and Karoo Basin of South Africa. A possible lacuna, spanning the Kungurian Nd Ufimian Stages, exists at the unconformity between the Wagina Sandstone and the underlying Carynginia Formation. Vitrinite reflectance indicates the Early Permian coal was buried to depths of 2.7-4.3 km in an interior sag basin between 4.3 and 5.8 km deep. Gravity modelling in the Irwin River Coalfield area shows that depth to basement varies from a maximum of 1700 m in the northern part to under 300 m in the south. Given the pre-existing mapped position of the Darling Fault, it is necessary to invoke a low density body immediately east of the fault and then a higher density body farther to the east in the models of traverses G1, G2, and G3. The low density body immediately east of the Darling Fault can be explained best as the result of shearing associated with the proto Darling Fault.(author). 26 figs, 2 plates, refs.

Le Blanc Smith, G.; Mory, A.J.; Lasky, R.P

1995-09-01

16

New Middle Permian palaeopteran insects from Lod?ve Basin in southern France (Ephemeroptera, Diaphanopterodea, Megasecoptera)  

Science.gov (United States)

Abstract Three new palaeopteran insects are described from the Middle Permian (Guadalupian) of Salagou Formation in the Lodève Basin (South of France), viz. the diaphanopterodean Alexrasnitsyniidae fam. n., based on Alexrasnitsynia permiana gen. et sp. n., the Parelmoidae Permelmoa magnifica gen. et sp. n., and Lodevohymen lapeyriei gen. et sp. n. (in Megasecoptera or Diaphanopterodea, family undetermined). In addition the first record of mayflies attributed to family Syntonopteridae (Ephemeroptera) is reported. These new fossils clearly demonstrate that the present knowledge of the Permian insects remains very incomplete. They also confirm that the Lodève entomofauna was highly diverse providing links to other Permian localities and also rather unique, with several families still not recorded in other contemporaneous outcrops.

Prokop, Jakub; Nel, Andre

2011-01-01

17

New Middle Permian palaeopteran insects from Lodève Basin in southern France (Ephemeroptera, Diaphanopterodea, Megasecoptera  

Directory of Open Access Journals (Sweden)

Full Text Available Three new palaeopteran insects are described from the Middle Permian (Guadalupian of Salagou Formation in the Lodève Basin (South of France, viz. the diaphanopterodean Alexrasnitsyniidae fam. n., based on Alexrasnitsynia permiana gen. et sp. n., the Parelmoidae Permelmoa magnifica gen. et sp. n., and Lodevohymen lapeyriei gen. et sp. n. (in Megasecoptera or Diaphanopterodea, family undetermined. In addition the first record of mayflies attributed to family Syntonopteridae (Ephemeroptera is reported. These new fossils clearly demonstrate that the present knowledge of the Permian insects remains very incomplete. They also confirm that the Lodève entomofauna was highly diverse providing links to other Permian localities and also rather unique, with several families still not recorded in other contemporaneous outcrops.

André Nel

2011-09-01

18

Structural evolution of the Permian-Triassic Cooper basin, Australia: Relation to hydrocarbon trap styles  

Energy Technology Data Exchange (ETDEWEB)

The structural and depositional history of the Cooper basin in eastern central Australia has revealed that the basin is a mildly compressional structural depression controlled by northwestrending and northeast-trending pre-Permian basement features. Pronounced pre-Permian compressions are indicated by northeast-trending major structures, the Gidgealpa-Merrimelia-Innamincka and Murteree-Nappacoongee trends. Detailed chronostratigraphic facies analysis, with closely spaced palynological control, of the Patchawarra Formation revealed that two pronounced phases of uplift occurred during the Sakmarian. The major intrabasin highs were rejuvenated during these tectonic events, as documented by crestal unconformities (middle and upper Patchawarra unconformities). Evidence of each event is dominantly tectonic in character, with similar depositional patterns over these highs related to each event. These events are also recognizable in midflank areas and basin margins with contemporaneous deposition in deeper parts of the basin. Results from this research show potential for future hydrocarbon discoveries within structural, stratigraphic, and structural/stratigraphic traps in the Cooper basin. Various trap styles are closely associated with faults, unconformities, and lateral facies changes. Lowside fault closures, onlap plays, and unconformity traps are expected to be well developed along intrabasinal highs, basin margins, and preexisting structures. The primary reservoir targets would be deltaic sequences comprising shoreline sandstones, distributary and delta-mouth bar deposits that may be well developed in synclinal areas, and flanks of intrabasin highs in the Copper basin.

Apak, S.N. [Geological Survey of Western Australia, East Perth (Australia); Stuart, W.J.; Lemon, N.M. [Univ. of Adelaide (Australia); Wood, G. [Santos Ltd., Adelaide (Australia)

1997-04-01

19

New Middle Permian palaeopteran insects from Lodève Basin in southern France (Ephemeroptera, Diaphanopterodea, Megasecoptera)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Three new palaeopteran insects are described from the Middle Permian (Guadalupian) of Salagou Formation in the Lodève Basin (South of France), viz. the diaphanopterodean Alexrasnitsyniidae fam. n., based on Alexrasnitsynia permiana gen. et sp. n., the Parelmoidae Permelmoa magnifica gen. et sp. n., and Lodevohymen lapeyriei gen. et sp. n. (in Megasecoptera or Diaphanopterodea, family undetermined). In addition the first record of mayflies attributed to family Syntonopteridae (Ephemeroptera) ...

Jakub Prokop; André Nel

2011-01-01

20

Late Permian–early Middle Triassic back-arc basin development in West Qinling, China  

Science.gov (United States)

The Late Permian-early Middle Triassic strata of the northern West Qinling area, northeastern Tibetan Plateau, are composed of sediment gravity flow deposits. Detailed sedimentary facies analysis indicates these strata were deposited in three successive deep-marine environments. The Late Permian-early Early Triassic strata of the Maomaolong Formation and the lowest part of the Longwuhe Formation define a NW-SE trending proximal slope environment. Facies of the Early Triassic strata composing the middle and upper Longwuhe Formation are consistent with deposition in a base-of-slope apron environment, whereas facies of the Middle Triassic Anisian age Gulangdi Formation are more closely associated with a base-of-slope fan depositional environment. The lithofacies and the spatial-temporal changes in paleocurrent data from these strata suggest the opening of a continental margin back-arc basin system during Late Permian to early Middle Triassic time in the northern West Qinling. U-Pb zircon ages for geochemically varied igneous rocks with diabasic through granitic compositions intruded into these deep-marine strata range from 250 to 234 Ma. These observations are consistent with extensional back-arc basin development and rifting between the Permian-Triassic Eastern Kunlun arc and North China block during the continent-continent collision and underthrusting of the South China block northward beneath the Qinling terrane of the North China block. Deep-marine sedimentation ended in the northern West Qinling by the Middle Triassic Ladinian age, but started in the southern West Qinling and Songpan-Ganzi to the south. We attribute these observations to southward directed rollback of Paleo-Tethys oceanic lithosphere, continued attenuation of the West Qinling on the upper plate, local post-rift isostatic compensation in the northern West Qinling area, and continued opening of a back-arc basin in the southern West Qinling and Songpan-Ganzi. Rollback and back-arc basin development during Late Permian to early Middle Triassic time in the West Qinling area explains: the truncated map pattern of the Eastern Kunlun arc, the age difference of deep-marine sediment gravity flow deposits between the Late Permian-early Middle Triassic northern West Qinling and the late Middle Triassic-Late Triassic southern West Qinling and Songpan-Ganzi, and the discontinuous trace of ophiolitic rocks associated with the Anyemaqen-Kunlun suture.

Li, Lin; Meng, Qingren; Pullen, Alex; Garzione, Carmala N.; Wu, Guoli; Wang, Yanling; Ma, Shouxian; Duan, Liang

2014-06-01

 
 
 
 
21

Schematic designs for penetration seals for a repository in the Permian Basin  

International Nuclear Information System (INIS)

The isolation of radioactive wastes in geologic repositories requires that human-made penetrations such as shafts, tunnels, or boreholes are adequately sealed. This report describes schematic seal designs for a repository in bedded salt referenced to the stratigraphy of the Permian Basin. The designs are presented for extensive peer review and will be updated as conceptual designs if the Permian Basin is selected as a candidate repository site. The principal material used in the seal system in the repository-level rooms and tunnels is crushed salt obtained from excavating the repository. It is anticipated that crushed salt will consolidate in response to closure of the repository rooms, to the degree that mechanical and hydrologic properties will eventually match those of undisturbed, intact salt. For Permian Basin Unit 4 salt, analyses indicate that this process will require approximately 700 years for a seal located at the base of one of the repository shafts (where there is little increase in temperature due to waste emplacement) and approximately 200 years for a seal located in a main passageway within the repository. These analyses are based on uncertain laboratory data regarding intact salt creep rates and crushed salt consolidation characteristics, and must be regarded as preliminary. Bulkheads composed of concrete, as well as bentonite-rich earth fill, are also included in the seal system as components which will have low permeability during the period required for salt consolidation

1985-01-01

22

Palynostratigraphy of the Middle Permian coal sequences of the Sydney Basin  

Energy Technology Data Exchange (ETDEWEB)

The appearance of several microspores within the Middle Permian coal sequences of the Sydney Basin permits widespread intrabasinal correlations. Dulhuntyispora parvithola appears within the Bulga Formation of the Wittingham Coal Measures, the Kulnura Marine Tongue of the Tomago Coal Measures, the Erins Vale Formation of the Illawarra Coal Measures in the Camden area and in the Gundangaroo Formation of the Illawarra Coal Measures in the Lithgow area. Microreticulatisporites bitriangularis appears within the Malabar Formation of the Wittingham Coal Measures, the upper Four Mile Creek Formation of the Tomago Coal Measures, the upper Wilton Formation of the Illawarra Coal Measures in the Camden area and in the Newnes Formation of the Illawarra Coal Measures in the Lithgow area. There are two basin-wide marine incursions within the Middle Permian sequence of the Sydney Basin: these are indicated in palynological samples by the presence of acritarchs. The position of these incursions with respect to the appearance of D. parvithola and M. triangularis implies synchronous deposition throughout the basin. These marine intervals cannot be correlated palynologically with marine intervals in the Bowen Basin. 43 references.

McMinn, A.

1985-09-01

23

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

Energy Technology Data Exchange (ETDEWEB)

The {delta}{sup 34}S, {sup 87}Sr/{sup 86}Sr 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 {sup 87}Sr/{sup 86}Sr ratios may be recorded in many of the samples. The general shape of the {sup 87}Sr/{sup 86}Sr 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 {sup 87}Sr/{sup 86}Sr 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.

Leary, D.A. (Exxon Production Research Co., Houston, TX (USA))

1990-05-01

24

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

1990-05-01

25

Biomarker analysis of Upper Permian lacustrine oil shales, Junggar basin, NW China  

Energy Technology Data Exchange (ETDEWEB)

Upper Permian lacustrine oil shales containing up to 34% TOC (total organic carbon) underlie approximately 50,000 km{sup 2} of the Junggar basin in western China, and appear to be the principal source of oils in the giant Karamay field in the northwestern Junggar and in several recent discoveries in other areas of the basin. The siliceous oil shales were deposited in a sediment-starved foreland basin during a period of predominantly humid climate. Previous biomarker studies of crude oils from Karamay field have documented an abundance of {beta}-carotane (which in some cases dominates the aliphatic hydrocarbon distribution) and gammacerane, suggesting a source bed deposited under hypersaline conditions. However, relatively complete outcrop exposures of finely laminated oil shales in the southern Junggar conspicuously lack evaporites, extensive dessication horizons, or other sedimentological evidence of playa lake environments. Indeed, the aliphatic hydrocarbon distribution in bitumen extracts from southern Junggar oil shales appear characteristic of freshwater to brakish water deposition of organic matter in an anoxic lake. Normal alkanes show a slight odd-over-even preference with relatively low levels of the C{sub 22}, n-alkane, pristane/phytane ratios close to unity, low {beta}-carotane and gammacerane levels, and the absence of C{sub 34}-C{sub 35} hopanes. This apparent difference in source bed depositional environments may be due to tectonic partitioning between separate depocenters of the Late Permian Junggar basin. Alternatively, hypersaline oil shale facies may be limited to deeper basinal areas, whereas upslope southern Junggar sediments record highstands in lake level or influx of fresh water from the adjacent drainage areas.

Carroll, A. (Stanford Univ., CA (USA))

1990-05-01

26

Permian Basin maturation: proof for pervasive magmatic heat flow in the Netherlands  

Science.gov (United States)

The area of the Permian Basin is marked by significant Stephanian-Permian magmatism that is related to the Variscanorogenic collapse, resulting in pervasive mantle upwelling. Large extrusive evidence is visible in the North German Basin and in the Central North Sea. Theoretical models for tectonic heat flow and maturity evolution show that mantle upwelling, underplating, and intrusions are likely to have a significant effect on maturity-depth trends. Tectonic modelling of selected wells shows that tectonic subsidence and exhumation can be reconciled with a significant heat flow pulse at the Stephanian-Permian, and this could well explain the widespread elevated depth gradient of maturity in Carboniferous rocks. The quantitative assessment of heat flow, which is based on a kinematic model of the process of orogenic collapse, shows that the mantle upwelling and underplating at the base of the crust proposed by earlier studies in fact provides insufficient heat flow to explain strongly elevated maturity-depth trends. However, the Southern part of the Texel IJsselmeer High shows unusually high maturation values that cannot be explained by the simple effect of burial alone. This area of high maturation is also associated with evidence of intrusive magmatic rocks. By modelling five wells in the Texel IJsselmeer High, we conclude that the burial of the sediments and a shallow intrusion in the upper crust provide an elevated heat flow mechanism that has a regional impact, consistent with observed high maturity-depth trends. In each well, the model that best matches the elevated maturity data of the Carboniferous demonstrates the impact of a large intrusion emplacement in the upper crust at the time of the collapse of the Variscan orogen. The impact of this magmatic intrusion at such a shallow depth is extremely likely to have brought the maturity to the gas window during the heat pulse, and, based on the tectonic subsidence record, the model allows us to position this pulse at late Carboniferous times.

Bonte, Damien; van Wees, Jan Diederik; Fattah, Rader Abdul; Nelskamp, Suzanne; Cloetingh, Sierd

2014-05-01

27

Getting to the source: aeolian influx to the Permian Delaware basin region  

Science.gov (United States)

Although an aeolian origin for the siliciclastics of the Permian (Guadalupian) Delaware and adjacent basins and shelf has been recognized, their source has remained elusive. An Ancestral Rockies source to the west and northwest has been traditionally favored. We propose instead that these sediments were derived from aeolian systems to the northeast and represented by the Whitehorse Group in the Anadarko Basin. This hypothesis is based upon (1) recognition of the aeolian nature of the Whitehorse, (2) regional correlation of the Whitehorse Group with portions of the Artesia Group, (3) paleoclimatic model-predicted and measured southwestward sediment transport for the Whitehorse, and (4) a proposed transport corridor over emergent mudflats along the northern margins of basisins in the Texas Panhandle and onto the New Mexico shelf. Potentially, a Whitehorse-Artesia link could show the formation of this mixed carbonate/siliciclastic system as the result of the interactions of diverse and distant environmental systems under eustatic and climatic forcing factors.

Kocurek, Gary; Kirkland, Brenda L.

1998-05-01

28

Illite/smectite clays preserving porosity at depth in Lower Permian Reservoirs, Northern Perth Basin  

Energy Technology Data Exchange (ETDEWEB)

The appraisal well Hovea-2, drilled in July 2002, was the first well in the onshore Perth Basin to discover commercial volumes of gas in sandstone reservoirs of the Artinskian (Early Permian) High Cliff Sandstone sealed beneath basal shales and siltstones of the Irwin River Coal Measures. A drill stem test in this formation, in the interval 2,370-419 mMDRT (measured depth below rotary table), flowed gas to surface at 16.5 MMcfd. Thereafter, the High Cliff Sandstone became an important play for exploration in the basin; however, no additional discoveries have been made in this reservoir, even though it has been tested in another seven wells (Jingemia-1, Eremia-1, Kunzia-1, Corybas-1, Yardarino-6, Hakia-2 and Bunjong-1).

D.D. Ferdinando; J.C. Baker; A. Gongora; B.A. Pidgeon

2007-07-01

29

Permian Bone Spring formation: Sandstone play in the Delaware basin. Part I - slope  

Energy Technology Data Exchange (ETDEWEB)

New exploration in the Permian (Leonardian) Bone Spring formation has indicated regional potential in several sandstone sections across portions of the northern Delaware basin. Significant production has been established in the first, second, and third Bone Spring sandstones, as well as in a new reservoir interval, the Avalon sandstone, above the first Bone Spring sandstone. These sandstones were deposited as submarine-fan systems within the northern Delaware basin during periods of lowered sea level. The Bone Spring as a whole consists of alternating carbonate and siliciclastic intervals representing the downdip equivalents to thick Abo-Yeso/Wichita-Clear Fork carbonate buildups along the Leonardian shelf margin. Hydrocarbon exploration in the Bone Spring has traditionally focused on debris-flow carbonate deposits restricted to the paleoslope. Submarine-fan systems, in contrast, extend a considerable distance basinward of these deposits and have been recently proven productive as much as 40-48 km south of the carbonate trend.

Montgomery, S.L. [Petroleum Consultant, Seattle, WA (United States)

1997-08-01

30

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

31

Evolution of groundwater from Permian and Triassic aquifers in the Thuringian basin, Germany  

Science.gov (United States)

The hydrochemical properties of shallow and deep groundwater with special emphasis on stable isotopes (2H, 18O, 34SSO4, 18OSO4) as well as rare earth elements (REE) are investigated to study the evolution of groundwater in the edge areas of the Thuringian basin (central Germany). The Thuringian basin is a syncline structure with an extension of 160 km in northwest-southeast and 100 km in northeast-southwest direction. It consists of sandstones, limestones, clays, gypsum and salts, that were deposited from the Late Permian until the Early Jurassic (approximately 250 to 180 million years ago). At the edge areas of the basin, sediments of Zechstein (Permian) and Bunter Sandstone (Early Triassic) are cropping out over a wide area being the catchment areas for ground water recharge of the main aquifers in Bunter Sandstone and Zechstein formations. In addition to the infiltration of atmospheric water, highly mineralized ascending groundwater occurs at fault systems leading to interactions between the aquifers. The isotope data of dissolved sulfates (34SSO4) indicate a terrestrial origin of sulfates in Early Bunter Sandstone as well as marine conditions for sulfate formation in Late Bunter Sandstone and Late Zechstein. Thus, sulfate isotopes can be used to identify the origin of water and to estimate the proportions of sulfates of different sources in mixing water. The isotopic composition of water in Bunter Sandstone aquifers in the eastern part of the basin indicate an increasing influence of sulfates from Late Bunter Sandstone in aquifers of Middle Bunter Sandstone along the groundwater flow towards the center of the basin. On the other hand there is no indication for mixing with Zechstein associated water in these aquifers. In contrast, in the northern part of the Thuringian basin and southward of the basin (south of the Thuringian forest) an interaction of Zechstein and Bunter Sandstone aquifers bound on fault systems becomes evident. The fractionations of rare earth elements in groundwater were determined after an enrichment procedure based on the method of Shabani (1992). Positive and negative Ce anomalies on PAAS (Post Achaean Australian shale) normalized REE fractionation pattern give hints on different redox conditions during groundwater evolution. Positive Ce anomalies were identified only on samples originated at Zechstein aquifers, whereas groundwaters in Bunter Sandstone aquifers with high redox potential show negative Ce anomalies, generally. References: Shabani, M.B., T. Akagi, and A. Masuda (1992): Preconcentration of trace rare earth elements in seawater by complexation with (2-ethylhexyl) hydrogen phosphate and 2-ethylhexyl dihydrogen phosphate adsorbed on a C18 cardridge and determination by inductively coupled plasma mass spectrometry: Anal. Chem. 64, 737-743.

Lonschinski, Martin; Merten, Dirk; Büchel, Georg

2014-05-01

32

Upper Permian magnetic stratigraphy of the lower Beaufort Group, Karoo Basin  

Science.gov (United States)

We carried out a magnetostratigraphic and geochronological study of late Permian sediments in the Karoo Basin of the Western Cape Province, South Africa. A continuous, ~700 m thick section of deltaic sediments of the upper Waterford Formation (uppermost Ecca Group) and the fluvial sediments of the Abrahamskraal Formation (lowermost Beaufort Group) were sampled at the meter scale. U-Pb dating of zircons from interbedded volcanic ash beds by ion microprobe (SHRIMP) provided absolute age constraints on the age of the sedimentary rocks. Paleomagnetic analysis reveals a partial overprint of the Natural Remanent Magnetization (NRM) that is tentatively ascribed to the emplacement of the Karoo Large Igneous Province in the Western Cape region during the middle Jurassic. A stable component of the NRM was found at temperatures higher than 450 °C and was interpreted as a Characteristic Remanent Magnetization (ChRM) acquired during deposition, supported by a positive reversals test for this dual polarity ChRM. The virtual geomagnetic pole position for the Waterford and Abrahamskraal Formations computed from the average ChRM direction is in general agreement with the late Permian directions for stable Gondwana. A significantly different average inclination, and thus paleomagnetic pole position, is obtained by correcting the inclination shallowing error by the Elongation-Inclination method (Tauxe and Kent, 2004). The presence of both normal and reversed polarity zones indicate deposition after the end of the Kiaman Superchron, moreover the polarity sequence is in good agreement with the Illawarra sequence of Steiner (2006). Our results indicate a Capitanian (late Guadalupian) age for the Abrahamskraal Fm., in agreement with the Late Permian age, based on presence of Glossopteris flora and Dicynodont fauna, traditionally assigned to the fluvial-lacustrine sediments of the Beaufort Group. However, the U-Pb zircon ages of ca. 264-268 Ma suggest an age of 269 Ma for the top of the Kiaman superchron.

Lanci, L.; Tohver, E.; Wilson, A.; Flint, S.

2013-08-01

33

Palynomorphs of Permian Gondwana coal from borehole GDH-38, Barapukuria Coal Basin, Bangladesh  

Energy Technology Data Exchange (ETDEWEB)

Thirty-two core samples of Permian Gondwana coal from three coal beds of borehole GDH-38, Barapukuria Coal Basin, Dinajpur, Bangladesh, were collected for palynological analysis. The lower coal bed (331.5-372.5 m) can easily be differentiated from the upper two coal beds by the presence of Alisporites, Cordaitina, Corisaccites, Hamiapollenites, Leuckisporites, Nuskoisporites, Tumoripollenites, Vestgisporites and Vittatina. It is difficult to palynologically differentiate the middle (198.1-208 m) and upper (162.3-172.9 m) coal beds as they contain a very limited number of specimens by which they can be identified. The middle bed is distinguished by the presence of Microbaculispora and Weylandites and the upper bed by the presence of a single taxon Acanthotriletes. Some of the vesiculate or saccate taxa extracted from these coal beds are typical of those occurring in Permian strata of Gondwana in India, South Africa, South America, Russia, Australia and Antarctica. They are thought to be derived from Glossopteris flora, which is characterised by an abundance of Pteridospermic plants of the gymnosperm group.

Akhtar, A.; Kosanke, R.M. [Geological Survey of Bangladesh, Dhaka (Bangladesh)

2000-07-01

34

Palynomorphs of Permian Gondwana coal from borehole GDH-38, Barapukuria Coal Basin, Bangladesh  

Science.gov (United States)

Thirty-two core samples of Permian Gondwana coal from three coal beds of borehole GDH-38, Barapukuria Coal Basin, Dinajpur, the north-northwestern part of Bangladesh, have been collected for palynological analysis. All samples except one yielded palynomorphs and some samples contain well-preserved and abundant palynomorphs of the gymnospermal and cryptogamic groups that are considered to be useful for future correlation studies. The lower coal bed (331.6-372.5 m) can easily be differentiated from the upper two coal beds by the presence of Alisporites, Cordaitina, Corisaccites, Hamiapollenites, Leuckisporites, Nuskoisporites, Tumoripollenites, Vestgisporites and Vittatina. It is difficult to palynologically differentiate the middle (198.1-208 m) and upper (162.3-172.9 m) coal beds as they contain a very limited number of specimens by which they can be identified. The middle bed is distinguished by the presence of Microbaculispora and Weylandites and the upper bed by the presence of a single taxon Acanthotriletes. Some of the vesiculate or saccate taxa extracted from these coal beds are typical of those occurring in Permian strata of Gondwana in India, South Africa, South America, Russia, Australia and Antarctica. They are thought to be derived from Glossopteris flora, which is characterised by an abundance of Pteridospermic plants of the gymnosperm group. ?? 2000 Elsevier Science Limited. All rights reserved.

Akhtar, A.; Kosanke, R. M.

2000-01-01

35

Palynomorphs of Permian Gondwana coal from borehole GDH-38, Barapukuria Coal Basin, Bangladesh  

Science.gov (United States)

Thirty-two core samples of Permian Gondwana coal from three coal beds of borehole GDH-38, Barapukuria Coal Basin, Dinajpur, the north-northwestern part of Bangladesh, have been collected for palynological analysis. All samples except one yielded palynomorphs and some samples contain well-preserved and abundant palynomorphs of the gymnospermal and cryptogamic groups that are considered to be useful for future correlation studies. The lower coal bed (331.6-372.5 m) can easily be differentiated from the upper two coal beds by the presence of Alisporites, Cordaitina, Corisaccites, Hamiapollenites, Leuckisporites, Nuskoisporites, Tumoripollenites, Vestgisporites and Vittatina. It is difficult to palynologically differentiate the middle (198.1-208 m) and upper (162.3-172.9 m) coal beds as they contain a very limited number of specimens by which they can be identified. The middle bed is distinguished by the presence of Microbaculispora and Weylandites and the upper bed by the presence of a single taxon Acanthotriletes. Some of the vesiculate or saccate taxa extracted from these coal beds are typical of those occurring in Permian strata of Gondwana in India, South Africa, South America, Russia, Australia and Antarctica. They are thought to be derived from Glossopteris flora, which is characterised by an abundance of Pteridospermic plants of the gymnosperm group.

Akhtar, A.; Kosanke, R. M.

2000-07-01

36

Geology and metallogeny of the uranium deposits in the Lodeve Permian basin (southern Massif Central, France)  

International Nuclear Information System (INIS)

The Permian continental basin of Lodeve, in the southern part of the Massif Central, 60 km west of Montpellier contains a significant uranium potential by French mining standards. The orebodies can take the form of ribbon-shaped, massive or even stratiform bodies, but always associated with bituminous facies beds and strong brittle tectonics. The major faults are sites of hydrothermal activity and in places hydraulic fracturing. Most of the uraniferous mineralisation is thought to have been associated with acid volcanism, contemporaneous with sedimentation, which could also have facilitated syn- and diagenetic preconcentrations of uranium. Later, in the course of two phases of hydrothermal mobilisation during the Jurassic and Cretaceous, uranium was remobilised on a large scale along faults containing bituminous material and impregnated with sulphides

1990-01-01

37

Investigation of deep permeable strata in the permian basin for future geothermal energy reserves  

Energy Technology Data Exchange (ETDEWEB)

This project will investigate a previously unidentified geothermal energy resource, opening broad new frontiers to geothermal development. Data collected by industry during oil and gas development demonstrate deep permeable strata with temperatures {ge} 150 C, within the optimum window for binary power plant operation. The project will delineate Deep Permeable Strata Geothermal Energy (DPSGE) assets in the Permian Basin of western Texas and southeastern New Mexico. Presently, geothermal electrical power generation is limited to proximity to shallow, high-temperature igneous heat sources. This geographically restricts geothermal development. Delineation of a new, less geographically constrained geothermal energy source will stimulate geothermal development, increasing available clean, renewable world energy reserves. This proposal will stimulate geothermal reservoir exploration by identifying untapped and unrealized reservoirs of geothermal energy. DPSGE is present in many regions of the United States not presently considered as geothermally prospective. Development of this new energy source will promote geothermal use throughout the nation.

Erdlac, Richard J., Jr.; Swift, Douglas B.

1999-09-23

38

Maceral composition and environment of deposition of Permian coals from the Parana Basin, Brazil  

Energy Technology Data Exchange (ETDEWEB)

The petrographic composition of polished pellets,blocks and thin sections of the Bonito and Barro Branco coal beds from Santa Catarina State, Charqueadas coal bed from Rio Grande do Sul State and Rio de Peixe coal bed from Parana State, Brazil were studied. These Gondwana coals are characterized by high percentage of inertinite, mineral matter and the fine grained macerals--vitrodetrinite, liptodetrinite and inertodetrinite. Long periods of dry weather and high oxidation conditions, characteristic plant communities of the depositional basin and washed-in or blown-in sediments from the margin of the basin are responsible for the high inertinite and mineral matter content, whereas the fine grained detrital macerals indicate a moderately energetic environment within the depositional basin. These Permian coals were formed under cool climatic (interglacial and postglacial) conditions with alternating rainy and dry seasons in fresh water swamps. The environmental changes in the coal swamp are interpreted from the petrographic variations within the coals. Forest moor, reed moor, subaquatic moor and open moor define the different coal facies during deposition. Subaquatic and open moor conditions were dominant during peat formation for the Bonito and Charqueadas coals beds, whereas a reed moor condition was dominant during peat formation for the Barro Branco and Rio do Peixe coal beds.

Kneller, W.A.; Wu, C.H.

1985-01-01

39

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

40

A glass ramp: shallow-water Permian spiculitic chert sedimentation, Sverdrup Basin, Arctic Canada  

Science.gov (United States)

Thick, widespread spiculitic chert and subordinate carbonate of the upper Permian (late Guadalupian to Lopingian) Degerböls and Lindstrom formation record deposition during a third-order, late Palaeozoic sea level cycle. The succession is interpreted to have accumulated as a ramp in a mid-latitude, relative low-energy setting that was periodically perturbed by storms, one of the few such occurrences of neritic spiculitic chert in the geological record. Sediments comprise seven lithofacies that can be placed in inner ramp to basinal paleoenvironments. Inner ramp facies range from fossiliferous glauconite-rich carbonate grainstone, to light spiculitic chert. The mid-ramp is typified by dark spiculitic chert containing few other fossils but typically textured by hummocky cross-stratification. Sediments in both environments are burrowed, with particularly conspicuous Zoophycos and Planolites. Dark, finely laminated spiculitic siltstone and shale characterize outer-ramp and basinal settings. The elevated trophic resources and abundant silica necessary for such sedimentation are interpreted to have resulted from upwelling.

Gates, Laura M.; James, Noel P.; Beauchamp, Benoit

2004-06-01

 
 
 
 
41

Thermomechanical analyses of conceptual repository designs for the Paradox and Permian Basins  

International Nuclear Information System (INIS)

The potential repositories are designed to accommodate all waste forms emplaced at various thermal loadings; specifically, commercial high-level waste (30 W/m2), spent fuel (15 W/m2), defense high-level waste (20 W/m2), and remote-handled and contact-handled transuranic nonheat-generating waste. The study evaluates the design parameters, primarily thermal loading, based on a comparison of calculable thermomechanical parameters with prescribed performance constraints. This evaluation was accomplished by numerical simulation using finite element techniques of the canister, disposal room, and repository regions of each potential site. Important thermal and thermomechanical results were compared with their prescribed constraint or limit value. All of the performance constraints were satisfied at the Davis Canyon site in the Paradox Basin for commercial high-level waste, spent fuel, and defense high-level waste at areal thermal loadings of 20 W/m2, 15 W/m2, and 20 W/m2, respectively. Similarly, for the Deaf Smith County site in the Permian Basin, commercial high-level waste, spent fuel, and defense high-level waste thermal loadings of 13.5 W/m2, 8.5 W/m2, and 6.0 W/m2, respectively, satisfied all of the performance constraints. 89 refs., 64 figs., 22 tabs

1987-01-01

42

Compositional trends in the Permian sandstones from the Denison Trough, bowen basin, queensland reflect changing provenance and tectonics  

Science.gov (United States)

Point-count data of sandstone samples collected from six sedimentary formations encountered in boreholes in the Permian sequence of the Denison Trough (an Australian backare/ retroarc foreland basin) provide information about the tectonic evolution of their source areas and the depositional sites. Plots of the detrital compositions of these Permian sandstones against borehole depths indicate that the Reids Dome Beds sandstones, containing highly abundant lithic/volcanolithic grains, mark the onset of intense compressional tectonics and arc volcanic activities to the east accompanied by extensional tectonics and subsidence in the trough. Folding and thrusting owing to intense compressional tectonics in the New England Fold Belt and Arc volcanism in the Camboon Volcanic Arc region to the east generated a great supply of recycled sediment and volcanic detritus that led to a rapid infilling of the subsiding Denison Trough during formation of the Reids Dome Beds sandstones in Early Permian time. The detrital composition of the sandstones of the overlying Cattle Creek Formation, Aldebaran Sandstone, and the Freitag Formation indicate gradually decreasing compressional tectonics and arc volcanism accompanied by increasingly dominant sediment-supply from the stable continental craton to the west. The Freitag Formation sandstone compositions mark the quietest tectonic and volcanic episode in the region, accompanied by subsidence of the Denison Trough owing to thermal cooling during the Middle Permian. The Peawaddy Formation and the Bandanna Formation sandstone compositions represent a Late Permian renewal of compressional tectonics and arc volcanism to the east accompanied by uplift and folding of the sedimentary strata, resulting in the formation of largely fluvial depositional environments in the Denison Trough. Modal compositions of the Bandanna Formation sandstones indicate that renewed arc volcanism and compressional tectonic activity attained maximum intensities during the Late Permian.

R., Ahmad; J. C., Tipper; Eggleton, R. A.

1994-03-01

43

Late Permian Palynology and depositional environment of Chintalapudi sub basin, Pranhita-Godavari basin, Andhra Pradesh, India  

Science.gov (United States)

The present study deals with the palynological dating, correlation and depositional setting of the sediments from bore cores MGP-11 and MGP-4 from Gauridevipet area of Chintalapudi sub-basin of Godavari master basin, south India. On the basis of palynological studies, three palynoassemblages have been identified, one in bore core MGP-11 a Faunipollenites (=Protohaploxypinus) and Striasulcites assemblage and two in bore core MGP-4; one is characterized by the dominance of striate bisaccates and Densipollenites and the other by Striatopodocarpites and Cresentipollenites palynoassemblages. The other stratigraphically significant taxa include Guttulapollenites hannonicus, Lunatisporites noviaulensis, Lunatisporites pellucidus, Densoisporites contactus, Chordasporites australiensis, Goubinispora spp., Lundbladispora microconata, Lundbladispora raniganjensis and Klausipollenites schaubergeri. The recovered taxa suggest a Late Permian, Lopingian age for these rocks. This interpretation is based on the correlation of the assemblages with similar assemblages from previous Gondwana studies chiefly Densipollenites magnicorpus Zone of Damodar Basin, India and Late Permian palynoassemblages from Africa, Antarctica, Australia and South America. On the basis of palaeobotanical affinity of the identified microflora it has been inferred that the peat forming plant community was composed mainly of gymnosperm pollen attributable to glossopterids, that includes striate and non-striate bisaccates and paucity of cordaites which includes monosaccates. Spores are subordinate and are derived from lycopsids (Lundbladispora, Densoisporites), sphenopsids (Latosporites) and filicopsids (Horriditriletes, Lophotriletes, Verrucosisporites, Osmundacidites, Leiotriletes, Callumispora, Brevitriletes and Microbaculispora) occurring in variable proportions. The dominance of subarborescent/arborescent vegetation suggests a development in a forest swamp probably in a small distant marginal part of the mire or periods of standing water. This flooding environment favoured the growth of herbaceous lycopsids, filicopsids and sphenopsids in the palaeomire. More or less similar environments of deposition have been deduced for both the sedimentary sequences on the basis of palynofacies analysis. Anaerobic, reducing, water logged peat-forming conditions have been inferred based on the abundance of phytoclasts. The relative abundance of structured organic matter implies the existence of a fairly dense vegetation cover in the hinterland. The charcoal fragments recovered from the present study area reflects a possible wildfire in the accumulated swamps or a wildfire in the hinterland after which the sediments were flushed by fluvial systems into the swamps.

Jha, Neerja; Pauline Sabina, K.; Aggarwal, Neha; Mahesh, S.

2014-01-01

44

A case study of exploitation in the Lovington Strawn Trend, Permian Basin, Lea County, New Mexico  

Energy Technology Data Exchange (ETDEWEB)

The Lovington New Mexico area, located in the northwest shelf of the Permian basin, produces oil from Pennsylvanian-age phylloid algal bioherms within the lower Strawn limestone. Strawn carbonates were deposited on the northwest flank of the Central Basin axis in a low-energy midramp setting. Algal bioherms developed as steep-sided, loaf-shaped buildups elongate in a dip direction. Mounds range from 20 to 180 ft (6-55 m) thick and average 112 mi (0.8 km) wide by 0.5 to 1 mi (0.8-1.6 km) long and occur at an average depth of 11,300 ft (3,444 m). Porosity occurs in the mound facies, usually in one massive zone with values ranging from 4 to 14%. Porous mounds are sealed by nonporous lime mudstones (intermound facies), the predominant facies within the Strawn limestone. A basinal black shale overlies the Strawn limestone across the play fairway and provides a source for Strawn oil. In the downflank portion of the play, skeletal grainstones occur beneath the Strawn shale, onlapping the mound and intermound facies. Areas of thick grainstone development are associated with poor production due to reduced porosity/permeability and possible loss of sealing facies. Prediction of undrilled mounds between well control is difficult from log, dipmeter, or drill cuttings data. Isolated Strawn limestone isopach thicks coincident with anomalous seismic character can be used to predict mound locations. Disrupted or anomalous seismic character is caused by thickening of the Strawn interval when porous and abrupt facies/velocity changes between mound and intermound limestone facies. Correct spatial imaging of the steep-sided algal mounds is critical in developing an accurate subsurface target. Once a prospect has been identified, a well-defined bottom-hole location is required to ensure a valid test of the prospect.

Shanks, K.A. (BP Exploration Inc., Houston, TX (USA)); Williams, M.C. (BP Exploration Inc., Glasgow (England))

1990-05-01

45

Rock mechanics evaluation of potential repository sites in the Paradox, Permian, and Gulf Coast Basins: Volume 1  

International Nuclear Information System (INIS)

Thermal and thermomechanical analyses of a conceptual radioactive waste repository containing commercial and defense high-level wastes and spent fuel have been performing using finite element models. The thermal and thermomechanical responses of the waste package, disposal room, and repository regions were evaluated. four bedded salt formations, in Davis and Lavender Canyons in the Paradox Basin of southeastern Utah and in Deaf Smith and Swisher counties in the Permian Basin of northwestern Texas, and three salt domes, Vacherie Dome in northwestern Louisiana and Richton and Cypress Creek Domes in southeastern Mississippi, located in the Gulf Coast Basin, were examined. In the Paradox Basin, the pressure exerted on the waste package overpack was much greater than the initial in situ stress. The disposal room closure was less than 10 percent after 5 years. Surface uplift was nominal, and no significant thermomechanical perturbation of the aquitards was observed. In the Permian Basin, the pressure exerted on the waste package overpack was greater than the initial in situ stress. The disposal room closures were greater than 10 percent in less than 5 years. Surface uplift was nominal, and no significant thermomechanical perturbation of the aquitards was observed. In the Gulf Coast Basin, the pressure exerted on the waste package overpack was greater than the initial in situ stress. The disposal room closures were greater than 10 percent in less than 5 years. No significant thermomechanical perturbation of the overlying geology was observed. 40 refs., 153 figs., 32 tabs

1987-01-01

46

Permian salt dissolution, alkaline lake basins, and nuclear-waste storage, Southern High Plains, Texas and New Mexico  

Energy Technology Data Exchange (ETDEWEB)

Areas of Permian salt dissolution associated with 15 large alkaline lake basins on and adjacent to the Southern High Plains of west Texas and eastern New Mexico suggest formation of the basins by collapse of strata over the dissolution cavities. However, data from 6 other alkaline basins reveal no evidence of underlying salt dissolution. Thus, whether the basins were initiated by subsidence over the salt dissolution areas or whether the salt dissolution was caused by infiltration of overlying lake water is conjectural. However, the fact that the lacustrine fill in Mound Lake greatly exceeds the amount of salt dissolution and subsidence of overlying beds indicates that at least Mound Lake basin was antecedent to the salt dissolution. The association of topography, structure, and dissolution in areas well removed from zones of shallow burial emphasizes the susceptibility of Permian salt-bed dissolution throughout the west Texas-eastern New Mexico area. Such evidence, combined with previous studies documenting salt-bed dissolution in areas surrounding a proposed high-level nuclear-waste repository site in Deaf Smith County, Texas, leads to serious questions about the rationale of using salt beds for nuclear-waste storage.

Reeves, C.C. Jr.; Temple, J.M.

1986-11-01

47

Permian salt dissolution, alkaline lake basins, and nuclear-waste storage, Southern High Plains, Texas and New Mexico  

International Nuclear Information System (INIS)

Areas of Permian salt dissolution associated with 15 large alkaline lake basins on and adjacent to the Southern High Plains of west Texas and eastern New Mexico suggest formation of the basins by collapse of strata over the dissolution cavities. However, data from 6 other alkaline basins reveal no evidence of underlying salt dissolution. Thus, whether the basins were initiated by subsidence over the salt dissolution areas or whether the salt dissolution was caused by infiltration of overlying lake water is conjectural. However, the fact that the lacustrine fill in Mound Lake greatly exceeds the amount of salt dissolution and subsidence of overlying beds indicates that at least Mound Lake basin was antecedent to the salt dissolution. The association of topography, structure, and dissolution in areas well removed from zones of shallow burial emphasizes the susceptibility of Permian salt-bed dissolution throughout the west Texas-eastern New Mexico area. Such evidence, combined with previous studies documenting salt-bed dissolution in areas surrounding a proposed high-level nuclear-waste repository site in Deaf Smith County, Texas, leads to serious questions about the rationale of using salt beds for nuclear-waste storage

1986-01-01

48

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

2012-10-01

49

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

Scientific Electronic Library Online (English)

Full Text Available SciELO South Africa | Language: English 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 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.

50

Thermal conductivity and diffusivity of Permian Basin bedded salt at elevated pressure and temperature  

International Nuclear Information System (INIS)

Measurements of thermal conductivity and diffusivity were made on five core samples of bedded rock salt from the Permian Basin in Texas to determine its suitability as an underground nuclear waste repository. The sample size was 100 mm in diameter by 250 mm in length. Measurements were conducted under confining pressures ranging from 3.8 to 31.0 MPa and temperatures from room temperature to 473 K. Conductivity showed no dependence on confining pressure but evidenced a monotonic, negative temperature dependence. Four of the five samples showed conductivities clustered in a range of 5.6 +- 0.5 W/m.K at room temperature, falling to 3.6 +- 0.3 W/m.K at 473 K. These values are approximately 20% below those for pure halite, reflecting perhaps the 5 to 20%-nonhalite component of the samples. Diffusivity also showed a monotonic, negative temperature dependence, with four of the five samples clustered in a range of 2.7 +- 0.4 x 10-6 m2/s at room temperature, and 1.5 +- 0.3 x 10-6 m2/s at 473 K, all roughly 33% below the values for pure halite. One sample showed an unusually high conductivity (it also had the highest diffusivity), about 20% higher than the others; and one sample showed an unusually low diffusivity (it also had the lowest conductivity), roughly a factor of 2 lower than the others. 27 references, 8 figures, 4 tables

1983-01-01

51

Composition of fluid inclusions in Permian salt beds, Palo Duro Basin, Texas, U.S.A.  

Science.gov (United States)

Several methods have been developed and used to extract and chemically analyze the two major types of fluid inclusions in bedded salt from the Palo Duro Basin, Texas. Data on the ratio K: Ca: Mg were obtained on a few of the clouds of tiny inclusions in "chevron" salt, representing the brines from which the salt originally crystallized. Much more complete quantitative data (Na, K, Ca, Mg, Sr, Cl, SO4 and Br) were obtained on ??? 120 individual "large" (mostly ???500 ??m on an edge, i.e., ??? ??? 1.6 ?? 10-4 g) inclusions in recrystallized salt. These latter fluids have a wide range of compositions, even in a given piece of core, indicating that fluids of grossly different composition were present in these salt beds during the several (?) stages of recrystallization. The analytical results indicating very large inter-and intra-sample chemical variation verify the conclusion reached earlier, from petrography and microthermometry, that the inclusion fluids in salt and their solutes are generally polygenetic. The diversity in composition stems from the combination of a variety of sources for the fluids (Permian sea, meteoric, and groundwater, as well as later migrating ground-, formation, or meteoric waters of unknown age), and a variety of subsequent geochemical processes of dissolution, precipitation and rock-water interaction. The compositional data are frequently ambiguous but do provide constraints and may eventually yield a coherent history of the events that produced these beds. Such an understanding of the past history of the evaporite sequence of the Palo Duro Basin should help in predicting the future role of the fluids in the salt if a nuclear waste repository is sited there. ?? 1987.

Roedder, E.; d'Angelo, W. M.; Dorrzapf, Jr. , A. F.; Aruscavage, P. J.

1987-01-01

52

Occurrence and significance of magnesite in Upper Permian (Guadalupian) Tansill and Yates Formations, Delaware Basin, New Mexico  

Energy Technology Data Exchange (ETDEWEB)

Magnesite (MgCO{sub 3}) occurs pervasively in a 270-ft (82-m) cored interval of Upper Permian (Guadalupian) shelf deposits from the northern rim of the Delaware basin portion of the Permian basin, New Mexico. In their core example, magnesite is found in tidal flat/lagoon and pisolite shoal dolomites and siltstones of the Tansill and uppermost Yates formations. The interval is overlain by magnesite-bearing anhydrite and a thick halite section of the (Ochoan) Salado Formation. The basinwide extent of magnesite is unknown. Magnesite may have formed either (1) during Ochoan deposition or thereafter, after burial of the Tansill and Yates formations, from dense brines originating from the overlying Salado evaporites; or less likely, (2) syndepositionally with the Tansill and Yates sediments. Preliminary measurements of stable carbon and oxygen isotopes for magnesite yield normal Permian values for {delta}{sup 13}C averaging + 6.84% (PDB) and slightly evaporitic values for {delta}{sup 18}O averaging + 1.04% (PDB); corrected {sup 87}Sr/{sup 86}Sr isotope composition averages 0.70687. Because a high content of associated uranium in the magnesite-rich part of the core causes large gamma-ray deflections similar to those for shale, and because the density of magnesite is close to that of anhydrite, the presence of magnesite could lead to improper evaluation of lithology and porosity from logs and could ultimately result in failure to recognize potential reservoir zones. 14 figs., 1 tab.

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

1990-02-01

53

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

54

U-Pb zircon ages from the southwestern Karoo Basin, South Africa - Implications for the Permian-Triassic boundary  

Science.gov (United States)

U-Pb ages determined using sensitive high-resolution ion microprobe-reverse geometry on 205 single-grain zircons from 16 ash beds within submarine fan deposits of the Ecca Group provide the first evidence of a marine Permian-Triassic (P-T) boundary in the Karoo Basin of South Africa. These U-Pb ages provide an objective basis for correlating the deep-marine sediments of the southwest Karoo Basin with fluvial-deltaic deposits in the central and eastern parts of the basin where the P-T boundary is recorded in a diverse macrofauna. Furthermore, these new zircon ages and their correlation imply asymmetric subsidence and variable sedimentation rates across the basin. ?? 2009 Geological Society of America.

Fildani, A.; Weislogel, A.; Drinkwater, N. J.; McHargue, T.; Tankard, A.; Wooden, J.; Hodgson, D.; Flint, S.

2009-01-01

55

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  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 Permian T-S (Tiverton...

Cisterna, Gabriela A.; Sterren, Andrea F.; Gutie?rrez, Pedro R.

2011-01-01

56

Preliminary correlation of palynological assemblages from Oman with the Granulatisporites confluens Oppel Zone of the grant formation (lower Permian), Canning Basin, Western Australia  

Science.gov (United States)

The presence of Granulatisporites confluens Archangelsky and Gamerro indicates an Asselian-Tastubian (lowermost Permian) age for glaciogene sediments in the Amal-6 borehole, Oman. This suggests that the Al Khlata Formation is in part coeval with glaciogene sediments of the Canning Basin, Western Australia, and sediments of the Chacoparana Basin, Argentina.

Stephenson, Michael H.

1998-05-01

57

Palaeoenvironments and palaeotectonics of the arid to hyperarid intracontinental latest Permian- late Triassic Solway basin (U.K.)  

Science.gov (United States)

The late Permian to late Triassic sediments of the Solway Basin consist of an originally flat-lying, laterally persistent and consistent succession of mature, dominantly fine-grained red clastics laid down in part of a very large intracontinental basin. The complete absence of body or trace fossils or palaeosols indicates a very arid (hyperarid) depositional environment for most of the sediments. At the base of the succession, thin regolith breccias and sandstones rest unconformably on basement and early Permian rift clastics. Overlying gypsiferous red silty mudstones, very fine sandstones and thick gypsum were deposited in either a playa lake or in a hypersaline estuary, and their margins. These pass upwards into thick-bedded, multi-storied, fine- to very fine-grained red quartzo-felspathic and sublithic arenites in which even medium sand is rare despite channels with clay pebbles up to 30 cm in diameter. Above, thick trough cross-bedded and parallel laminated fine-grained aeolian sandstones (deposited in extensive barchanoid dune complexes) pass up into very thick, multicoloured mudstones, and gypsum deposited in marginal marine or lacustrine sabkha environments. The latter pass up into marine Lower Jurassic shales and limestones. Thirteen non-marine clastic lithofacies are arranged into five main lithofacies associations whose facies architecture is reconstructed where possible by analysis of large exposures. The five associations can be compared with the desert pavement, arid ephemeral stream, sabkha, saline lake and aeolian sand dune environments of the arid to hyperarid areas of existing intracontinental basins such as Lake Eyre and Lake Chad. The accommodation space in such basins is controlled by gradual tectonic subsidence moderated by large fluctuations in shallow lake extent (caused by climatic change and local variation) and this promotes a large-scale layer-cake stratigraphy as exemplified in the Solway basin. Here, the dominant fine-grained mature sandstones above the local basal reg breccias suggest water-reworking of wind-transported sediment, as in the northern part of the Lake Chad basin. Growth faulting occurs in places in the Solway basin, caused by underlying evaporite movement, but these faults did not significantly affect pre-late Triassic sedimentation and did not expose pre-Permian units above the basal breccias. There is no evidence of post-early Permian rifting anywhere during deposition of the late Permian to middle Triassic British succession although the succession is often interpreted with a rift-basin model. The arid to hyperarid palaeoclimate changed little during deposition of the Solway basin succession, in contrast to Lakes Eyre and Chad: and this is attributed to tectonic and palaeolatitude stability. Unlike the later Mesozoic- Cenozoic, only limited plate movements took place during the Triassic in western Europe, palaeolatitude changed little, and the Solway Basin remained in the northern latitudinal desert belt from early to mid-Triassic times. However, the influence of the early Triassic impoverished biota on environmental interpretations needs further study.

Brookfield, Michael E.

2008-10-01

58

Characterizing the Hydrogeology and Surface Waters of a Select Portion of the Permian Basin Using an Arc Hydro Groundwater Database  

Science.gov (United States)

Atmospheric levels of anthropogenic CO2 have increased from a pre industrial level of 280 parts per million to a 1999 concentration of over 365 parts per million, largely due to expanding use of fossil fuels for human energy needs. Current levels are the highest observed in over 350,000 years. The desire to stabilize atmospheric concentrations of CO2 supports research on and development of technologies that will achieve this end. Sequestration of carbon in geologic formations is one such technology that is actively being pursued. Of particular interest is the Permian Basin of eastern Texas and southeastern New Mexico, a basin with substantial saline and brine aquifers that might be very suitable for carbon sequestration, and also a basin that has been producing oil and gas for well over 100 years, a process which utilizes CO2 injection for enhanced recovery. Understanding the interactions between those portions of the Permian Basin proposed for CO2 sequestration and those portions currently utilized as a water supply (i.e., Pecos River and freshwater aquifers) is a critical component of the R&D in this area because of the reliance of a large agricultural community and other delicate legal and environmental balances prevailing in this region. The main purpose of this study is to create a detailed hydrological model with emphasis on hydrogeology and surface waters of a select portion of the Permian Basin, delineated by the Sacramento Mountains to the west and the Delaware Basin to the east, with the long term goal that this study will be one component of a total basin characterization and evaluation. Arc Hydro groundwater data model framework is used to create a database of the study area. The construction of this database is an initial step in the integration of the plethora of oil, gas, and water databases (e.g., IHS Database, New Mexico Subsurface and Core Libraries, and WATERS Database), and provides a platform for the addition of hydrological and geological data (e.g., from the New Mexico Bureau of Geology's Sacramento Mountains Project). The database is then coupled with a numerical model used to explore groundwater surface water interactions and aquifer connectedness at both the regional and site scale, with particular emphasis placed on those phenomena elucidating the interdependencies between the Pecos Slope and the Delaware Basin. This application of the Arc Hydro groundwater data model will be expanded upon and its predictive capabilities further developed such that the effects of CO2 sequestration in the Capitan Reef aquifer can be evaluated.

Morse, J. T.; McPhearson, B. J.; Land, L. A.

2006-12-01

59

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 m"2/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

60

Fibers and cylinders of cryptomelane-hollandite in Permian bedded salt, Palo Duro Basin, Texas  

International Nuclear Information System (INIS)

Fibers and thin-walled, hollow cylinders of cryptomelane-hollandite have been found in both the chevron and the clear salt from various drill cores in Permian bedded salt from the Palo Duro Basin, Texas. The authors have found fibers or cylinders from only the lower San Andres Formation units 4 and 5, the upper San Andres Formation, and the Salado-Transill salt. The fibers are inorganic, light to dark reddish brown, pleochroic, highly birefringent, filamentary single crystals, < 1 to ? 5 ?m in diameter, with length-to-diameter ratios of at least 20:1. The fibers can be straight and/or curved, can bifurcate, can form loops, waves or spirals, and can be isolated or in parallel groups. Detailed petrographic analyses show no evidence for recrystallization or deformation of the enclosing salt after fiber formation. Although the authors observations do not provide a definitive explanation for fiber origin, they suggest that the fibers grew in situ by a solid-state diffusional process at low temperatures. The cylinders are pleochroic, highly birefringent, light to dark reddish brown, hollow, thin-walled, open-ended right cylinders, having a 1- to 2-?m wall thickness and variable lengths and diameters. There also appear to be single crystals of cryptomelane-hollandite, but these are found almost entirely in fluid inclusions in the chevron and clear salt. Their presence in the primary halite suggests that they were formed contemporaneously with the chevron structure and were accidentally trapped in the fluid inclusions. The observation of cylinders partially or completely enclosed by salt stratigraphically above large fluid inclusions suggests that natural downward fluid-inclusion migration has occurred, in response to the geothermal gradient

1987-01-01

 
 
 
 
61

Petrographic approach to the study of organic microfossils from the Irati Subgroup (Permian, Paraná Basin, Brazil)  

Science.gov (United States)

Early diagenetic chert, infrequently exploited in Phanerozoic micropaleontology, was examined for organic-walled microfossils in petrographic thin sections of silicified dolostones from diverse levels and localities of the Assistência Formation (Permian, Paraná Basin) in the state of São Paulo, Brazil. In contrast to previous palynological studies of this formation, the use of thin sections allowed direct observation in three dimensions of common palynomorphs, as well as benthic microbial mats preserved in situ in various stages of their life cycles and degradation. As in palynological residues from the more well-known shale of this formation, the chert contains wind-dispersed pollen grains and phytoclasts derived from terrestrial sources and planktonic cryptarchs (unornamented coccoidal unicellular or colonial palynomorphs). However, only in the chert is it possible to see much more delicate microfossils, such as abundant cyanobacteria of the in situ benthic microbiota as well as chlorophycean microalgae of the microphytoplankton. Post-depositional processes affecting the formation have destroyed all but the most resistant organic remains in the other lithologies, such that only rare, degraded pollen grains are seen in the unsilicified dolostone of the formation, and in the shale the vast majority of microfossils have been compacted to flattened disks. On the other hand, early silicification not only preserved organic remains at an incipient stage of decomposition but also impeded significant further degradation due to compaction, recrystallization, and oxidation. Thus, the petrographic study of such chert can complement traditional palynological investigations in Phanerozoic rocks by furnishing hitherto unavailable information, especially with regard to benthic organic microfossils and fragile organic-walled phytoplankton normally absent from organic residues.

Calça, Cléber Pereira; Fairchild, Thomas R.

2012-04-01

62

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

63

Thermal conductivity and diffusivity of Permian Basin bedded salt at elevated pressure and temperature  

Energy Technology Data Exchange (ETDEWEB)

Measurements of thermal conductivity and diffusivity were made on five core samples of bedded rock salt from the Permian Basin in Texas to determine its suitability as an underground nuclear waste repository. The sample size was 100 mm in diameter by 250 mm in length. Measurements were conducted under confining pressures ranging from 3.8 to 31.0 MPa and temperatures from room temperature to 473 K. Conductivity showed no dependence on confining pressure but evidenced a monotonic, negative temperature dependence. Four of the five samples showed conductivities clustered in a range of 5.6 +- 0.5 W/m.K at room temperature, falling to 3.6 +- 0.3 W/m.K at 473 K. These values are approximately 20% below those for pure halite, reflecting perhaps the 5 to 20%-nonhalite component of the samples. Diffusivity also showed a monotonic, negative temperature dependence, with four of the five samples clustered in a range of 2.7 +- 0.4 x 10/sup -6/ m/sup 2//s at room temperature, and 1.5 +- 0.3 x 10/sup -6/ m/sup 2//s at 473 K, all roughly 33% below the values for pure halite. One sample showed an unusually high conductivity (it also had the highest diffusivity), about 20% higher than the others; and one sample showed an unusually low diffusivity (it also had the lowest conductivity), roughly a factor of 2 lower than the others. 27 references, 8 figures, 4 tables.

Durham, W.B.; Boro, C.O.; Beiriger, J.M.; Montan, D.N.

1983-10-01

64

Diagenetic history and hydrocarbon potential of Upper Permian carbonate buildups, Wegener Halvoe area, Jameson Land basin, east Greenland  

Energy Technology Data Exchange (ETDEWEB)

The Upper Permian of Jameson Land includes two carbonate sequences, the Karstryggen and Wegener Halvoe formations. The Karstryggen Formation contains hypersaline carbonates and localized evaporites that were heavily weathered and dissected prior to deposition of the overlying strata. The overlying Wegener Halvoe Formation represents an abrupt and extensive marine inundation over the underlying karstified Karstryggen surface. Bryozoan-brachiopod-algal-cement buildups of the Wegener Halvoe Formation are localized on karstic highs, and show up to 150 m of depositional relief. The diagenetic histories of the core and flank facies are very different. Core facies porosity was initially obliterated by marine cements, but repeated meteoric exposure altered unstable core facies constituents. This alteration produced extensive secondary porosity through grain and cement leaching with local collapse brecciation. Flank strata, however, underwent little sea-floor diagenesis, and low permeability and mineralogically stable grain composition protected these strata from meteoric alteration. Subsequent fracturing and hydrothermal fluid flow, however, flushed hydrocarbons and filled pores with ferroan calcite, barite, fluorite, galena, and baroque dolomite. This heating and flushing is thought to have been especially intense in the Wegener Halvoe region; thus, more basinal areas may still have reservoirs containing significant oil in equivalent Upper Permian limestones. If, as is likely, the sea level changes affecting the Greenland Permian were eustatic, then this study may provide significant clues to porosity development throughout the largely unexplored northern Zechstein basin and the Arctic basin of the Barent Sea. This study also provides some important connections to the probably time-equivalent Guadalupian carbonate reservoir rocks of west Texas-New Mexico and Wyoming.

Scholle, P.A.; Ulmer, D.S. (Southern Methodist Univ., Dallas, TX (United States)); Stemmerik, L. (Greenland Geological Survey, Copenhagen (Denmark))

1991-04-01

65

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

66

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

67

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

68

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

International Nuclear Information System (INIS)

Laboratory measurements have been made of the thermal conductivity and diffusivity of four rock salts, two anhydrites, and two dolomites bordering the Cycle 4 and Cycle 5 bedded salt formations in the Permian Basin in Deaf Smith County, Texas. Measurement conditions ranged 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 two Cycle 4 salt samples, conductivity over the temperature range explored fell from 5.5 to 3.75 W/m.K, and diffusivity fell from about 2.7 to 1.7 x 10"-"6 m"2/s. One of the Cycle 5 salts was a single crystal which had anomalous results, but the other had a low conductivity, about 3.4 W/m.K, with very weak temperature dependence, and a high diffusivity, 3.8 to 2.5 x 10"-"6 m"2/s over the temperature range. In the nonsalts, conductivity and diffusivity decreased 10 to 20% over the temperature range explored, which was 308 < T < 373 K. Typical values at 308 K for conductivity were 5.4 W/m.K for both anhydrites and 3.4 and 2.6 W/m.K for the two different dolomite samples. Approximate values at 308 K for diffusivity were 2.3 x 10"-"6 m"2/s for the anhydrites and 1.4 x 10"-"6 m"2/s for both the dolomites. The coefficient of thermal linear expansion was measured for the Cycle 5 salt and nonsalts over 308 < T < 493 and 0.1 < P < 30.0 MPa. Typically, the coefficient 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 at a rate of roughly 5 x 10"-"8 K"-"2 at all pressures. 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

69

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

70

Lower Permian stems as fluvial paleocurrent indicators of the Parnaíba Basin, northern Brazil  

Science.gov (United States)

A comprehensive biostratinomic study was carried out with abundant stems from the Lower Permian Motuca Formation of the intracratonic Parnaíba Basin, central-north Brazil. The fossils represent a rare tropical to subtropical paleofloristic record in north Gondwana. Tree ferns dominate the assemblages (mainly Tietea, secondarily Psaronius), followed by gymnosperms, sphenophytes, other ferns and rare lycophytes. They are silica-permineralized, commonly reach 4 m length (exceptionally more than 10 m), lie loosely on the ground or are embedded in the original sandstone or siltstone matrix, and attract particular attention because of their frequent parallel attitudes. Many tree fern stems present the original straight cylindrical to slightly conical forms, other are somewhat flattened, and the gymnosperm stems are usually more irregular. Measurements of stem orientations and dimensions were made in three sites approximately aligned in a W-E direction in a distance of 27.3 km at the conservation unit "Tocantins Fossil Trees Natural Monument". In the eastern site, rose diagrams for 54 stems indicate a relatively narrow azimuthal range to SE. These stems commonly present attached basal bulbous root mantles and thin cylindrical sandstone envelopes, which sometimes hold, almost adjacent to the lateral stem surface, permineralized fern pinnae and other small plant fragments. In the more central site, 82 measured stems are preferentially oriented in the SW-NE direction, the proportion of gymnosperms is higher and cross-stratification sets of sandstones indicate paleocurrents mainly to NE and secondarily to SE. In the western site, most of the 42 measured stems lie in E-W positions. The predominantly sandy succession, where the fossil stems are best represented, evidences a braided fluvial system under semiarid conditions. The low plant diversity, some xeromorphic features and the supposedly almost syndepositional silica impregnation of the plants are coherent with marked dry seasons. Thick mudstones and some coquinites below and above the sandy interval may represent lacustrine facies formed in probably more humid conditions. The taphonomic history of the preserved plants began with exceptional storms that caused fast-flowing high water in channels and far into the floodplains. In the eastern site region, many tree ferns only fell, thus sometimes covering and protecting plant litter and leaves from further fragmentation. Assemblages of the central and western sites suggest that the trees were uprooted and transported in suspension (floating) parallel to the flow. Heavier ends of stems (according to their form or because of attached basal bulbous root mantle or large apical fronds) were oriented to upstream because of inertial forces. During falling water stage, the stems were stranded on riverbanks, usually maintaining the previous transport orientation, and were slightly buried. The perpendicular or oblique positions of some stems may have been caused by interference with other stems or shallow bars. Rare observed stems were apparently waterlogged before the final depositional process and transported as bedload. The differences of interpreted channel orientations between the three sites are expected in a braided fluvial system, considering the very low gradients of the basin and the work scale in the order of tens of kilometers. The mean direction of the drainage probably was to east and the flows apparently became weaker downstream. This study seems to provide reliable data for paleocurrent interpretations, especially considering areas with scarce preserved sedimentary structures.

Capretz, Robson Louiz; Rohn, Rosemarie

2013-08-01

71

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)

1998-05-13

72

Carboniferous Permian facies and tectono-stratigraphic successions of the glacially influenced and rifted Carnarvon Basin, western Australia  

Science.gov (United States)

The Carnarvon Basin of Western Australia is a rift basin that contains a thick (up to 5 km) succession of late Carboniferous-early Permian glacially influenced marine sedimentary strata. These rocks accumulated in near-polar paleolatitudes along the uplifted and glaciated margin of the west Australian Shield (Pilbara Craton). Three stratigraphic successions (I, II, III) can be recognised, each characterised by distinct facies associations that record different stages in the tectonic evolution of the basin and associated changes in the rate of basin subsidence and sediment accommodation. A lowermost succession (I) comprises rapidly deposited (30 m/Ma) glacially influenced marine strata (Lyons Group) containing palynomorphs of Westphalian-Tastubian (early Sakmarian) and possibly older age. Strata are dominated by subaqueously deposited sediment gravity flow facies. Succession II is composed of richly fossiliferous cool water shales (Callythara and Cordalia formations) that record much reduced sedimentation rates (2 m/Ma). In turn, shales are overlain by an uppermost succession (III) of shallow marine, wave- and storm-influenced sandstone (Moogooloo Sandstone). Comparison with other rift basin fills indicates that Succession I likely records initial basin infilling where abundant coarse debris was produced by faulting and glaciation of the adjacent Pilbara Craton. Shales of Succession II mark a phase of 'sediment underfilling' characterized by rapid tectonic subsidence, an increase in relative sea level and reduced sediment supply. Shallow water sandstone facies of Succession III record a late stage in the tectonic cycle when subsidence rates had decreased and sediment supply outpaced accommodation. Such successions, where found in other late Paleozoic basins, are widely interpreted in terms of glacioeustatically driven changes in sea level resulting from deglaciation events across Gondwana. Instead, the three successions within the Carnarvon Basin are argued to reflect a dominantly tectonic control on sedimentation and preservation.

Eyles, Carolyn H.; Mory, Arthur J.; Eyles, Nicholas

2003-01-01

73

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

74

Provenance study of Permian non-marine sandstones and conglomerates of the Krkonoše Piedmont Basin (Czech Republic): exotic marine limestone pebbles, heavy minerals and garnet composition  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This study focuses on identifying major source areas in several stratigraphic intervals in the Permian sediments of the Krkonoše Piedmont Basin and integrates it with existing sedimentological data. Pebbles in Cisuralian-Guadalupian conglomerates of alluvial fans, nearshore lacustrine and lacustrine fan-delta deposits that were deposited close to the northwestern and southeastern basin margin, respectively, correspond almost exclusively to local material from adjacent crystalline complexes. ...

2009-01-01

75

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

76

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, Co_6_0 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

77

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

78

The Permian Whitehill Formation (Karoo Basin, South Africa): deciphering the complexity and potential of an unconventional gas resource  

Science.gov (United States)

A key energy policy objective of the South African government is to diversify its energy mix from coal which constitutes 85% of the current mix. Gas will play a key role in the future South African economy with demand coming from electricity generation and gas-to-liquids projects. A study on world shale reserves conducted by the Energy Information Agency (EIA) in 2011 concluded that there could be as much as 485 Tcf recoverable reserves of shale gas in the South African Karoo Basin. However, the true extent and commercial viability is still unknown, due to the lack of exploration drilling and modern 3D seismic. The present study compiles existing data from literature review and new data from outcrop analogue studies on the Permian Whitehill Formation, the main target formation for future shale gas production, including thickness, depth, maturity, TOC, lithologies, sedimentary and organic facies, and dolerite occurrence to provide a first reference dataset for further investigations and resource estimates.

Götz, Annette E.

2014-05-01

79

Evidence of lacustrine sedimentation in the Upper Permian Bijori Formation, Satpura Gondwana basin: Palaeogeographic and tectonic implications  

Energy Technology Data Exchange (ETDEWEB)

The Upper Permian Bijori Formation of the Satpura Gondwana basin comprising fine- to coarse-grained sandstone, carbonaceous shale/mudstone and thin coal bands was previously interpreted as the deposits of meandering rivers. The present study documents abundance of wave ripples, hummocky and swaley cross-stratification and combined flow bedforms in the Bijori Formation, suggesting that a significant part of the formation was deposited in a wave-agitated environment. Evidence of near-emergent depositional conditions provided by repeated occurrence of rootlet beds and hydromorphic paleosols, local flooding surfaces denoting rapid fluctuation of water level, occurrences of temnospondyl vertebrate fossils, and absence of tidal signatures and marine fossils suggest a lacustrine rather than marine depositional regime. The lack of documented contemporaneous lacustrine or marine sediments in the Satpura Gondwana basin posed a major problem of basin-scale palaeogeographic reconstruction. The existence of Bijori lake solves the problem and the lake is inferred to have acted as repository for the contemporaneous alluvial drainage. Development of the large Bijori lake body implies generation of accommodation space exceeding the rate of sediment supplied and thus represents locus of high tectonic subsidence. Transition of fluvial sediments with red mudstone and calcareous soil profile in the lower part of the succession to carbonaceous shale and coal-bearing lacustrine sediments in the upper part, denote a change from a warm semi-arid climate with seasonal rainfall to a more humid one.

Chakraborty, T.; Sarkar, S. [Indian State Institute, Calcutta (India). Geological Studies Unit

2005-06-01

80

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 glacial-marine mudstones and sandy mudstones. The palynological assemblages yielded by 32 samples collected from two outcrops and thirty borehole samples demonstrate that not significant floral changes...

Beri, A.

2010-01-01

 
 
 
 
81

Paleomagnetism of the Carboniferous-Permian Patquia Formation, Paganzo basin, Argentina: implications for the apparent polar wander path for South America and Gondwana during the Late Palaeozoic  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The magnetic properties of the Carboniferous-Permian red beds of the Patquía Formation at Punta del Viento, Sierra de Umango and some previously reported localities, all in the Paganzo Basin (Argentina), have been studied. Whereas all sites are characterized by hematite as the main magnetic carrier and a reversed-polarity magnetic remanence, we found a pattern of variation in magnetic properties along the integrated column for Patquía Formation. The Lower Member (Late Carboniferous) showed ...

Geuna, S. E.

2010-01-01

82

A sedimentological analysis of sediments corresponding to the San Gregorio Formation )Lower Permian), located in the eastern border of the North Uruguayan Basin, Sierra Guazunambi  

International Nuclear Information System (INIS)

A sedimentological analysis of sediments corresponding to the San Gregorio Formation (Lower Permian), located in the eastern border of the Norte Uruguayan Basin, Sierra Guazunambi, Cerro Largo Departament was made. Facies analysis of about 100 otucrops fand more than 1.300 meters, in an area of 45 square kilometers showed diamictites rhytmites and massive sandstones, formed by gravitational sedimentary flows. Also present are prodelta mudrocks and deltaic front sandstones.(author)

1998-05-13

83

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Stárková M; Rapprich V; Breitkreuz Ch

2011-01-01

84

Geology of permian basin in the northeast of Uruguay: Sedimentology exam about uranium trace  

International Nuclear Information System (INIS)

The Uranium project was prepared from BRGM to DINAMIGE. Its has got three zones of investigation: zone 1 composed by precambrian basin in the N W; zone 2 the precambrian insular shelf and rocks belts; zone 3 wich include parts of the basin Cretaceous in Salto and Santa Lucia

1982-01-01

85

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

Energy Technology Data Exchange (ETDEWEB)

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.

Dunagan, J.F. Jr.; Kadish, K.A.

1977-11-01

86

The Permian basin geology in the north of Uruguay.Sedimentology exam about the uranium signs  

International Nuclear Information System (INIS)

The basin is located in the Precambrian insular shelf limited to the North. East and South. The North (Brazil) and south (Uruguay) edge are constituted by the insular shelf ancient nucleus which dates from 2000 million years.

1982-01-01

87

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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<...

MikulᚠR; Martínek K

2006-01-01

88

Outlook for oil and gas content (sedimentary rocks) at great depths. [Possibilities at 4 to 8 km depth in the Permian Basin of Poland  

Energy Technology Data Exchange (ETDEWEB)

The possibilities are examined for prospecting for oil and gas fields at depths over 4000 m. An analysis is made of the difficulties which develop during drilling at these depths, and also the cost of these operations. A comparison is made of the oil and gas basins of the world, genesis of hydrocarbon fields, geological structure, collector properties of the rocks, etc. are described. Results of analysis of oil and gas content of the deeply occurring levels 4-8 km indicate that the Permian basin of Poland is promising for prospecting not only for oil, but mainly gas fields at depths over 4000 m.

Maksimow, S.; Ancupow, P.; Fomkin, K.; Karnkowski, P.; Korab, Z.; Lodzewska, M.

1982-01-01

89

Dispersal syndromes of fossil seeds from the Lower Permian of Paraná Basin, Rio Grande do Sul, Brazil.  

Science.gov (United States)

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. PMID:22441595

Souza, Juliane M; Iannuzzi, Roberto

2012-03-01

90

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

2009-01-01

91

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

92

Development strategy in a fractured dolomite reservoir, Permian Basin, Southwestern USA  

Energy Technology Data Exchange (ETDEWEB)

The Permian (Guadalupian) San Andres reservoir at Keystone field, in Winkler County, Texas, is divided into 3 major stratigraphic units and 12 flow units on the basis of multiple upward-shoaling cycles of shallow-water marine to tidal-flat carbonate facies. Minor amounts of siliciclastic material concentrated in tidal-flat rocks impart a gamma-ray signature that allows correlation with well logs. These rocks are now thoroughly dolomitized and cemented with anhydrite and gypsum. Most of the resource is in the upper five flow units, and the original upper flow units indicates that the highest concentration of hydrocarbons is in the center of the study area, with a 1,500-ft-wide, 100-ft-thick fairway of high saturations having a northwest-southeast trend. Matrix permeabilities in this reservoir are very low, commonly less than 1 md in rocks having porosities of nearly 10 percent. Now wells in areas of highest original oil in place initially produce at rates up to 120 barrels of oil per day. However, these high production rates are commonly short lived and decline an average of 75 percent in the first 6 months. Vertical fractures in this reservoir are visible in cores and on a microimage log. Early floodwater breakthrough occurred without increased oil production in a pilot waterflood. These production characteristics, combined with direct observations of fractures, indicate that productivity is dependent on fracture permeability. Borehole asymmetry and regional stress measurements suggest that the direction of principal compressive stress, which dictates the strike of fractures that effectively transmit fluids, is northeast-southwest. Thus, horizontal boreholes parallel to the strike of maximum oil volume and perpendicular to the strike of effective fractures will maximize primary recovery. Recognition that injected water must load fractures before effectively sweeping the matrix will be critical in designing an effective waterflood.

Major, R.P.; Holtz, M.H. [Univ. of Texas, Austin, TX (United States)

1995-06-01

93

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.

MikulᚠR

2006-03-01

94

Facies and rank of the Permian Kupferschiefer from the Lower Rhine Basin and NW Germany  

Energy Technology Data Exchange (ETDEWEB)

The Kupferschiefer of the Lower Rhine Basin and of NW Germany is a typical black shale containing C{sub org} values between 0.5 and 9.1%. On average it contains 4% C{sub org}. In coal petrographic terms the organic matter of the Kupferschiefer is characterized by well preserved liptinite as sporinite (mainly derived from the pollen grains of conifers) in the area of the Lower Rhine Basin and as alginite towards the centre of the Kupferschiefer sea. The high content of bituminite in all of the samples shows that the main source of organic matter is derived from plankton and bacteria. Vitrinite and inertinite are rare. The rank of the organic matter in the sediment varies between the lignite stage (Lower Rhine Basin) and the bituminous coal stage (NW Germany). Geochemical investigations have shown that residual heat from the Krefeld High was active until the lower Zechstein. This has caused a change in the chemical composition of the organic matter but did not express itself in the optical parameters. Inhomogeneities of the organic matter in low-rank and bituminization in higher-rank materials influence the vitrinite reflectance. Fluorescence measurements are more sensitive in sapropelic sediments and oil shales than vitrinite reflectance. It is evident that the red/green ratio is more reliable in view of diagenesis studies than the lambda max of the fluorescence spectra. Geochemical parameters are partly much more sensitive towards thermal stress as compared to vitrinite reflectance, e.g. metalloporphyrin concentrations decrease with increasing temperatures. The parameter covers a temperature range from ca. 40{degree}C to 80{degree}C. The weighted average mass of the vanadyl-cycloalkano-porphyrins is suitable to characterize the influence of temperature on the Kupferschiefer between ca. 40{degree}C and 150 {degree}C. 30 refs., 9 figs.

Wolf, M.; David, P.P.; Eckardt, C.B.; Hagemann, H.W.; Puettmann, W. (Aachen University of Technology (Germany, F.R.). Lehrstuhl fuer Geologie, Geochemie und Lagerstaetten des Erdoel' s und der Kohle)

1989-12-01

95

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

International Nuclear Information System (INIS)

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 "4"0Ar*. K-Ar dates on leonites and kieserites are also low due to "4"0Ar* 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

96

Stratigraphy and Geochemistry of the Lower Permian Esayoo Volcanics, Northwest Ellesmere Island: Insights into Sverdrup Basin Paleogeography  

Science.gov (United States)

The Esayoo Volcanics consist of altered Lower Permian basalts that outcrop on northwest Ellesmere Island and northeast Axel Heiberg, within the Sverdrup Basin, Arctic Canada. Rifting in the Sverdrup Basin initiated in the Early Carboniferous and ceased during the Early Permian. The Esayoo volcanics geochemically classify as alkaline to transitional within-plate-basalts, with high Ti/Y and Zr/Y ratios. Eruptions are coincident with two rifting pulses of Sakmarian and Kungurian age. During the 2011 July field season, ten stratigraphic sections of the Esayoo Volcanics were measured at four locations on northwest Ellesmere Island: Borup Fiord Pass, Oobloyah Bay, Ricker Glacier and Mount Leith. The Esayoo Volcanics reach a maximum thickness of 450 m near Oobloyah Bay, and thin west, east and north of Oobloyah Bay with respective thicknesses of 140 m, 69 m and 75 m. At Oobloyah Bay, volcanic rocks occur at two stratigraphic levels. The lower Esayoo unit lies within the Raanes Formation, a mixed clastic-carbonate, and further west at Ricker Glacier within the upper Hare Fiord Formation, a black siliceous shale-siltstone. The upper Esayoo unit is below the Assistance Formation, carbonate-rich to clean quartz sandstone, and below the Sabine Bay Formation, a clean quartz sandstone with abundant cross-beds. Thin 1 to 2 m shales that indicate maximum flooding surfaces overlie both the upper and lower Esayoo units. Each measured section was divided into individual flow units that averaged 7 m thick. Dominant textures observed within individual flow units include: thin 2-3 cm thick amygdule-rich bases transitioning into thick 2-10 m thick massive flow interiors; frothy, amygdule-rich flow tops 1-3 m thick; and chaotic vesicular units with amygdules ranging from 0.5-3 cm in width and pervasive cross-cutting calcite veins and stringers. The lower level at Oobloyah Bay is composed of a laminated volcaniclastic rock that is rich in heterozoan marine bioclasts, with associated pillow basalts and a capping peperite- a mix of carbonates clasts and juvenile igneous material. The volcanic textures and facies observed within the lower Esayoo level suggest explosive, submarine volcanism. Within the upper Esayoo level, thin vesicle-rich bases within flow units; vesicle pipes, peperites and conglomerates suggest these volcanics were effusive flows that underwent volatile segregation and rapid degassing. These textures suggest volcanic-water interaction during eruption. Along with the extensive cross bedding within the Sabine Bay and Assistance Formations, a likely depositional environment for the upper Esayoo level is a fluvial-deltaic environment. Litho-sequence stratigraphic cross sections constructed representative of measured Esayoo sections indicate that the lower and upper Esayoo levels are bounded within transgressive sequences. In addition to these physical observations, seventy Esayoo Volcanic samples were analyzed for whole rock geochemistry and seven samples are being prepared for Samarian - Neodymium isotope analyses. The geochemistry of these volcanics will further develop the differences and similarities of the source rock between the lower and upper levels, and constrain the tectonic implications the Esayoo Volcanics indicate.

Morris, N. J.; Beauchamp, B.; Cuthbertson, J. P.; Chau, Y.

2012-12-01

97

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

98

Age and significance of the Platypus Tuff Bed, a regional reference horizon in the upper Permian Moranbah coal measures, north Bowen Basin  

International Nuclear Information System (INIS)

The Platypus Tuff Bed in the Permian Moranbah Coal Measures provides a basin-wide marker horizon traceable for over 300 km along strike. The bed is a tephra event unit, the product of a large-scale volcanic eruptive episode involving a pyroclastic volume > 10 km3. The relatively even thickness (?1-1.5 m) of the tuff across the entire northern Bowen Basin (?10 000 km2) implies a distant source. The tuff is ash-rich and its original geochemistry has been compromised by diagenetic alteration. Crystal content (10-15%) is dominated by quartz, suggesting a rhyolitic association. SHRIMP U-Pb analysis of zircons indicates an age of 258.9 ± 2.7 Ma for the Platypus Tuff Bed, confirming the Late Permian age that has generally been assigned to the Blackwater Group. The age framework now apparent for the coal-bearing Blackwater Group suggests an average depositional rate ranging from ?133 m/106 years for its eastern depocentre in the northern Bowen Basin to ?70 m/106 years in more marginal settings to the west. Copyright (2001) Geological Society of Australia

2001-04-01

99

Age and significance of the Platypus Tuff Bed, a regional reference horizon in the Upper Permian Moranbah Coal Measures, north Bowen Basin  

Energy Technology Data Exchange (ETDEWEB)

The Platypus Tuff Bed in the Permian Moranbah Coal Measures provides a basin-wide marker horizon traceable for over 300 km along strike. The bed is a tephra event unit, the product of a large-scale volcanic eruptive episode involving a pyroclastic volume {gt} 10 km{sup 3}. The relatively even thickness of the tuff across the entire northern Bowen Basin implies a distant source. The tuff is ash-rich and its original geochemistry has been compromised by diagenetic alteration. Crystal content (10-15%) is dominated by quartz, suggesting a rhyolitic association. SHRIMP U-Pb analysis of zircons indicates an age of 258.9 +/- 2.7 Ma for the Platypus Tuff Bed, confirming the Late Permian age that has generally been assigned to the Blackwater Group. The age framework now apparent for the coal-bearing Blackwater Group suggests an average depositional rate ranging from about to 133 m/10{sup 6} years for its eastern depocentre in the northern Bowen Basin to similar to 70 m/10{sup 6} years in more marginal settings to the west.

Michaelsen, P.; Henderson, R.A.; Crosdale, P.J.; Fanning, C.M. [James Cook University of North Queensland, Townsville, Qld. (Australia). School of Earth Science

2001-07-01

100

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

 
 
 
 
101

Radionuclides distribution in blooming of the permian sediments from the Irati Formation of the Parana Basin  

International Nuclear Information System (INIS)

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 226Ra, 238U, 32Th and 40K 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 238U were smaller for the limestones (17.80 ±0.09 Bq.Kg-1), larger for the bituminous shales (125.5 ± 2.6 Bq.Kg-1 with enrichment of uranium in the sample (200), 548 ± 16 Bq.Kg-1, upper part of the column), and intermediate for the rhythmits (23.0 ± 1,3 Bq.Kg-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-1 for the limestones and rhythmits, 79.5 nGy.h-1 for the bituminous shales and 329.5 nGy.h-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)

2008-01-01

102

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  

Directory of Open Access Journals (Sweden)

Full Text Available 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 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.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 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.

Gabriela A Cisterna

2011-07-01

103

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 SciELO Chile | Language: English 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 iden [...] tificación de las asociaciones megaflo-rísticas NBG y de Intervalo, y de la palinozona DM (Raistrickia densa-Convolutispora muriornata), del Carbonífero Tardío, en la 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 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.

104

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

2012-03-01

105

Liassic U-Pb age of the Rabejac pitchblende. Isotopic arguments for a Permian uraniferous preconcentration in the Lodeve basin (Herault)  

International Nuclear Information System (INIS)

Located in the basal part of the Saxonian formations of he Lodeve basin, the massive pitchblendes of the Rabejac ore deposit provide an age of 183 ± 4 Ma (Pb-Pb isochron), consistent with a Liassic mobilization of uranium in southern Massif central previously dated in the U ore deposits of Lodeve (Herault), Bertholene (Aveyron) and Pierres-Plantees (Lozere). This mobilization is related to the circulation of rather hot saline fluids (3-14%, 130-2500C) induced by the tectonic phase of continental crust thinning (horsts, grabens, tilted blocks) which preceded the opening of the Ligurian-Piemontais ocean. Using Concordias diagrams we discuss the isotopic composition of the initial lead incorporated into the Rabejac pitchblendes during their cristallization which appears to have been radiogenic. This constitutes the first isotopic argument in favour of a primary U concentration during Permian times in the Lodeve basin

1989-01-01

106

Perspectives and perils of using U-Pb zircon geochronology to constrain stratigraphic age: lessons from the Permian-Triassic Karoo basin, South Africa  

Science.gov (United States)

The Karoo basin contains an important Carboniferous-Jurassic sedimentary record that chronicles the amalgamation of Pangea, subduction along the southern Panthallasan margin and later opening of the South Atlantic, Southern, and Indian oceans. It also preserves a robust record of the end-Permian extinction, Earth's largest paleobiologic crisis. Fortuitously, this stratigraphic record is interleaved with numerous air-fall volcanic ashes likely derived from a continental magmatic system, part of which is currently exposed in the Choiyoi igneous province of South America. Our U-Pb geochronology of air-fall ash zircon from the Ecca and Beaufort Groups via SHRIMP analysis, along with LA-ICP-MS U-Pb analysis of detrital zircon from interbedded sandstones indicate that magmatic activity of this system likely persisted for at least 50 Ma. Particularly noteworthy is that uppermost Ecca Group detrital zircon signature exhibits few Precambrian ages and abundant Permian-Triassic ages; thus, by the start of marginal marine deposition, Karoo basin clastic influx was primarily sourced by some part of the Permian-Triassic Panthallassic magmatic system (i.e., the Choiyoi igneous province or its southern equivalent). Detrital zircon U-Pb ages suggest initial zircon formed within this magmatic system by ~300 Ma and that the apex of zircon crystallization occurred at ~265-275 Ma, after which, zircon crystallization decreased through time. We hypothesize that over the long duration of magmatic evolution, the melt began to become depleted with respect to zircon, such that by ~260 Ma, the melt became primarily undersaturated with respect to zircon. As a result, zircon was no longer a major accessory phase and ultimately after ~250 Ma was extruded only in scant trace amounts. This interpretation is also supported by U-Pb zircon geochronology on a few dozen Ecca and Beaufort Group ashes from across the Karoo basin. Individual ash ages were determined from statistically-robust, coherent populations of single U-Pb zircon ages. When interpreted in the context of recent ash U-Pb zircon geochronology results of others, the results depict a regional and repeatable occurrence of Permian ashes within the Triassic Beaufort Group that are consistently older than or within statistical error of ash ages found in the Ecca Group, despite the stratigraphic position of Ecca Group ashes 100's to >1000 m downsection of the Beaufort Group ashes. Lacking a reasonable geological explanation for this inversion, it appears that zircon within Beaufort Group ashes are of recycled or xenocrystic origin and yield coherent U-Pb zircon age populations which are older than the ash depositional age. Thus, even when high analytical precision is attained and Pb-loss is considered, ash ages determined by U-Pb zircon geochronology may not reliably demarcate the record of the end-Permian extinction and associated environmental changes preserved within Karoo basin strata. Furthermore, any stratigraphic age constrained solely by U-Pb zircon age populations from one or even a few separate ash beds may in fact be spurious given the evolution of zircon saturation within the magmatic system that sourced the ash.

Weislogel, A. L.; Mckay, M. P.; Dean, J.; Fildani, A.

2013-12-01

107

Phanerozoic tectono-stratigraphic evolution of the Trans-Pecos and Permian basin regions (Mexico, Texas, New Mexico) using Landsat imagery, subsurface and outcrop data  

Energy Technology Data Exchange (ETDEWEB)

Integrating regional Landsat imagery, outcrop field studies, and subsurface data has resulted in a more comprehensive understanding and delineation of the tectono-stratigraphic evolution of the Trans-Pecos region. Landsat imagery were acquired and registered to the existing 1:25000 scale maps and mosaiced to create a regional view of the Trans-Pecos and Permian basin region. The imagery were used to extrapolate and map key stratigraphic and tectonic elements after calibration from documented outcrop and subsurface data. The interpretations aided in the extrapolation of scattered control information and were critical in the complete reconstruction of the geologic history of the area. The Trans-Pecos Phanerozoic history comprises five tectono-depositional phases, and these have controlled the shape of the modem landscape: (1) Late Proterozoic rifting (Gondwana from Laurentia), and development of the Early-Middle Paleozoic Tobosa basin; (2) Pennsylvanian collision (South and North Americas), and differentiation of the Tobosa basin into the Midland, Delaware, Orogrande, and Pedregosa basins separated by basement blocks: Central Basin Platform, Diablo Platform, Burro-Florida Platform; (3) Middle Mesozoic transtensional rifting (Mexico from North America), and Late Jurassic failed rifting of the Mexican Chihuahua and Coahuila Troughs west and south of the Diablo Platform; (4) Late Mesozoic Laramide collision (Mexico and Texas), and development of the Chihuahua fold/thrust belt limited by the western margin of the Diablo Platform; (5) Late Cenozoic North American basin and Range rifting, and development of Rio Grande grabens, block-faulted mountains, and volcanics. The Tobosa basin was a passive-margin interior sag; its continental margin was south of the Marathons.

Markello, J.R.; Sarg, J.F. [Mobil Technology Corporation, Dallas, TX (United States)

1996-08-01

108

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

109

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

110

Fluvial architecture as a response to two-layer lithospheric subsidence during the Permian and Triassic in the Iberian Basin, eastern Spain  

Science.gov (United States)

The stratigraphy of a sedimentary basin is mainly the result of the long-term response of a depositional surface to prolonged subsidence. However, the real nature of interrelations between fluvial architecture and subsidence is still unknown. Herein, we present new data on these relationships by combining the results of detailed sedimentological field work with data acquired through automated forward modelling and backstripping for the alluvial Permian and Triassic sediments of the SE Iberian Ranges. Using this methodology, we determined tectonic subsidence of the basin by means of backstripping analysis and crust and lithospheric mantle stretching factors ( ? and ?, respectively) using forward modelling technique. Results indicated that a configuration of two individual and independent layers during lithospheric subsidence for each tectonic phase fit better for this time of the studied basin evolution than the assumption of subsidence due to a single layer spanning the whole lithosphere. For this study, we simplified fluvial geometries as two main types: isolated (I) and amalgamated (A), with subtypes in each case. Different order bounding surfaces (b.s.) were distinguished in the field, although we only selected those affecting the whole basin under study. These included those b.s. of clear tectonic origin, ranging from individual basin boundary-fault pulses produced over periods of approximately 1 My to those arising from major tectonic events, such as the beginning of extension in the basin, causing major changes in basin geometry over periods of 3-5 My. The comparison of ? and ? values and fluvial geometries for each identified tectonic phase in the basin evolution, revealed some possible relationship between subsidence and fluvial geometry: Sections showing the most varied fluvial architectural geometries, including ribbon and nested forms, were related to higher ? and ? stretching factors values indicating tectonic phases of greater stretching and subsidence. When both stretching factors were similar and close to 1, fluvial geometry was basically reduced to amalgamated geometry type. Wider ranging of fluvial geometries was associated with stages of basin development in which crust and upper mantle activities differed, that is, showing larger differences of ? and ? stretching factors values. The related slope changes are proposed as the main surface control of fluvial styles. Combination of subsidence with other possible controlling factors such as avulsion rate, climate or budget of sediments, gives rise to the definitive alluvial architecture of a basin.

López-Gómez, José; Arche, Alfredo; Vargas, Henar; Marzo, Mariano

2010-01-01

111

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

Science.gov (United States)

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 Lea??o-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 SiO2 and Al2O3 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 Lea??o-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. ?? 2006 Elsevier B.V. All rights reserved.

Kalkreuth, W.; Holz, M.; Kern, M.; Machado, G.; Mexias, A.; Silva, M. B.; Willett, J.; Finkelman, R.; Burger, H.

2006-01-01

112

États de contraintes et mécanismes d'ouverture et de fermeture des bassins permiens du Maroc hercynien. L'exemple des bassins des Jebilet et des RéhamnaStates of stresses and opening/closing mechanisms of the Permian basins in Hercynian Morocco. The example of the Jebilet and Réhamna Basins  

Science.gov (United States)

The fracturing analysis in the Permian basins of Jebilet and Rehamna (Hercynian Morocco) and the underlying terranes allowed us to suggest a model for their opening. Three tectonic episodes are distinguished: a transtensional episode NNE-SSW-trending (Permian I), occurring during the opening along sinistral wrench faults N70-110-trending, associated with synsedimentary normal faults; a transpressive episode ESE-WNW-trending (Permian II), initiating the closure, the normal faults playing back reverse faults and the N70 trending faults dextral wrench faults; a compressional episode NNW-SSE (post-Permian, ante-Triassic), accentuating the closure and the deformation and putting an end to the Tardi-Hercynian compressive movements. To cite this article: A. Saidi et al., C. R. Geoscience 334 (2002) 221-226.

Saidi, Amal; Tahiri, Abdelfatah; Ait Brahim, Lahcen; Saidi, Maraim

113

Diagenesis of clay minerals and K-bentonites in Late Permian/Early Triassic sediments of the Sichuan Basin (Chaotian section, Central China)  

Science.gov (United States)

Detailed clay mineralogical analyses were carried out on Late Permian/Early Triassic carbonate sediments exposed on the Chaotian section (Sichuan Basin, Central China). The clay assemblages are dominantly composed of illite in platform carbonates and clay seams, and illite-smectite mixed-layers (I/S) in tuff layers (K-bentonites) intercalated in the carbonate succession. Detrital and authigenic volcanogenic clay minerals have been partially replaced through illitisation processes during burial, raising questions about diagenetic effects. The precise determination of I/S occurring in K-bentonites shows that the sediments reached a temperature of about 180 °C, which is consistent with (1) previous estimates based on fluid-inclusion homogenisation temperature analysis, (2) the burial depth of the sedimentary series deduced from the post-Palaeozoic geological history of the Sichuan Basin and (3) the new data (Tmax) obtained on organic matter indicating the transition between oil and gas windows. The Wangpo Bed, located close to the Guadalupian-Lopingian Boundary, is interpreted either as a volcanic acidic tuff or as a clastic horizon. This controversial origin probably results from mixed volcanogenic and detrital influences. The Wangpo Bed is therefore interpreted as a reworked bentonite as revealed by the occurrence of I/S similar to those found in tuff layers, together with preserved detrital kaolinite.

Deconinck, J. F.; Crasquin, S.; Bruneau, L.; Pellenard, P.; Baudin, F.; Feng, Q.

2014-02-01

114

Numerical classification of coal-bearing cycles of Early Permian Barakar coal measures of eastern-central India Gondwana basins using Q-mode cluster analysis  

Energy Technology Data Exchange (ETDEWEB)

Q-mode cluster analysis is applied to classify the fining upward cycles of Early Permian Barakar coal measures from 14 localities of eastern central India Gondwana basins. Two distinct clusters are recognised on the basis of overall similarity of upward transition probability values of embedded Markov chain statistics. Cluster A comprise 9 localities representing fining upward asymmetrical cycles of very coarse to coarse sandstone {yields} interbedded fine sandstone-shale {yields} shale {yields} coal {yields} coarse sandstone, whereas Cluster B include 5 localities represented by symmetrical cycles i.e. very coarse to coarse sandstone {yields} interbedded fine sandstone-shale {yields} shale {yields} coal {yields} shale. The development of asymmetrical cycles together with abundance of very coarse to coarse sandstone is attributed to rapid lateral migration of braided channels, whereas the deposition of symmetrical cycles with subequal amount of coarse to medium sandstone and fine elastics including coal correspond to slow and gradual overstepping of meandering stream channels and associated subenvironments across the alluvial plain.

Tewari, R.C.

1997-11-01

115

First record of petrified Permian pecopterids from the Paraná Basin, Brazil (Corumbataí Formation, Passa Dois Group, northeastern State of São Paulo): Morphology, anatomy and paleoecological implications  

Science.gov (United States)

Petrified pecopterids are described for the first time in the Paraná Basin. They were collected at an outcrop of the Corumbataí Formation (Passa Dois Group, Middle Permian) in the Municipality of Piracicaba (State of São Paulo, Brazil). The assemblage is composed of Pecopteris taguaiensis Rohn and Rösler, 1986, Pecopteris sp. 1, Pecopteris sp. 2 and Pecopteris sp. 3. An emendation to the diagnosis of P. taguaiensis is proposed on the basis of the characteristics shown by the preserved three-dimensional external leaf morphology and partially by the epidermis (not available in the previously described impressions). The small size of the pinnules, the thick, downward-rolled leaf lamina, the thick veins, the straight walls of the epidermal cells, and the trichomes of the four pecopterid taxa may be interpreted as xeromorphic features developed in response to relatively dry climatic conditions and/or direct incidence of the sunlight. The leaves were impregnated with silica before the final burial, considering that they are fragmented, not deformed and associated with angular breccia clasts.

Tavares, Tatiane M. V.; Rohn, Rosemarie

2009-02-01

116

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

117

Shahejie-Shahejie/Guantao/Wumishan and Carboniferous/Permian Coal-Paleozoic Total Petroleum Systems in the Bohaiwan Basin, China (based on geologic studies for the 2000 World Energy Assessment Project of the U.S. Geological Survey)  

Science.gov (United States)

This report discusses the geologic framework and petroleum geology used to assess undiscovered petroleum resources in the Bohaiwan basin province for the 2000 World Energy Assessment Project of the U.S. Geological Survey. The Bohaiwan basin in northeastern China is the largest petroleum-producing region in China. Two total petroleum systems have been identified in the basin. The first, the Shahejie&ndashShahejie/Guantao/Wumishan Total Petroleum System, involves oil and gas generated from mature pods of lacustrine source rock that are associated with six major rift-controlled subbasins. Two assessment units are defined in this total petroleum system: (1) a Tertiary lacustrine assessment unit consisting of sandstone reservoirs interbedded with lacustrine shale source rocks, and (2) a pre-Tertiary buried hills assessment unit consisting of carbonate reservoirs that are overlain unconformably by Tertiary lacustrine shale source rocks. The second total petroleum system identified in the Bohaiwan basin is the Carboniferous/Permian Coal–Paleozoic Total Petroleum System, a hypothetical total petroleum system involving natural gas generated from multiple pods of thermally mature coal beds. Low-permeability Permian sandstones and possibly Carboniferous coal beds are the reservoir rocks. Most of the natural gas is inferred to be trapped in continuous accumulations near the center of the subbasins. This total petroleum system is largely unexplored and has good potential for undiscovered gas accumulations. One assessment unit, coal-sourced gas, is defined in this total petroleum system.

Ryder, Robert T.; Qiang, Jin; McCabe, Peter J.; Nuccio, Vito F.; Persits, Felix

2012-01-01

118

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

International Nuclear Information System (INIS)

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

1986-12-01

119

Late Paleozoic volcanism in the central part of the Southern Permian Basin (NE Germany, W Poland): facies distribution and volcano-topographic hiati  

Science.gov (United States)

Based on facies analysis of more than 5,500 m cores of 45 deep wells, three large sub-provinces have been defined for the Lower Rotliegend volcanic rocks in the central Southern Permian Basin (SPB) in northeastern Germany and western Poland. Additional data came from unpublished descriptions of more than 200 wells. The three sub-provinces are: (a) the Mecklenburg-Vorpommern Sub-Province (MVSP) dominated by silica-rich lava domes and subvolcanic intrusions, (b) the Eastern Brandenburg Sub-Province (EBSP) dominated by a Mg-andesite shield volcano complex, which extends into western Poland, and (c) the Flechtingen-Altmark Sub-Province (FASP) with prominent ignimbrite sheets punctuated by lava domes and flows. Whereas in NE Germany thickness of up to 2,300 m have been found in places, in western Poland ignimbrites and other pyroclastic deposits as well as andesitic and silica-rich lava complexes accumulated successions of a few hundreds of meters. A hiatus of up to 30 Ma occurs between the Lower Rotliegend volcanic and sedimentary rocks (Asselian-Sakmarian), and Upper Rotliegend II sediments (Upper Wordian-Capitanian). Upper Rotliegend I deposits are known from a few wells and outcrops, only. Previous studies postulated solely intrabasinal tectonics to account for this major unconformity. However, under semiarid to arid conditions as assumed for the Rotliegend of the SPB both SiO2-rich lava complexes and silica-poor shield volcanoes can be expected as being extremely resistant to weathering and erosion. Most probably these bodies “drowned” in a regolith formed by physical weathering, rarely removed by torrential rain. Thus, the silica-rich lava complexes and the shield volcanoes in the Central European Basin System (CEBS) can be viewed as long-living morphological highs, with intervolcanic depressions in between. In these intervolcanic depressions, syn- to postvolcanic successions of conglomeratic to sandy alluvial fan sediments and lake to mud flat deposits accumulated during the Upper Rotliegend I. They show numerous pedogenic horizons representing times of non-deposition. During the Upper Rotliegend II, the remaining volcano-topography was filled up with alluvial, eolian and playa deposits. In some places in western Poland, covering was not complete until the Zechstein (Latest Permian). At the same time, soil formation and/or erosion in the upper part of SiO2-rich complexes and shield volcanoes remained subordinate. Consequently, the volcano-topographic hiatus on top of the volcanic complexes comprises the maximum period of time, whereas in the intervolcanic depressions this time splits into periods of deposition and numerous minor intraformational hiati. Intrabasinal tectonic activity cannot be ruled out as one major control of the Rotliegend depositional evolution in the subsiding SPB. However, the presence of weathering-resistant volcanic edifices led to the formation of long-lasting depositional gaps in many regions of the central SPB.

Geißler, Marion; Breitkreuz, Christoph; Kiersnowski, Hubert

2008-09-01

120

Petroleum Geology of the Palo Duro Basin, Texas Panhandle.  

Science.gov (United States)

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 petrole...

P. R. Rose

1986-01-01

 
 
 
 
121

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

122

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

123

Sr evolution in the Upper Permian and Lower Triassic carbonates, northeast Sichuan basin, China: Constraints from chemistry, isotope and fluid inclusions  

International Nuclear Information System (INIS)

Petrographic features, C, O and Sr isotopes, rare earth and trace elements were determined, and fluid inclusions were analyzed on various stages of interparticle cements and vug-fillings from the Upper Permian and Lower Triassic sour reservoirs in northeastern Sichuan basin. The aim was to assess the origin and evolution of palaeo-waters in the carbonates. The original water was contemporary seawater, from which marine cements precipitated with slightly high Sr contents (mean 1911 ppm), 87Sr/86Sr ratios from 0.7067 to 0.7082 and nonluminescent CL. The palaeo-seawater was diluted by meteoric water, as indicated by bright cathodoluminescence (CL) and Sr-depletion (0–516 ppm) in low-temperature calcite. When buried to temperatures of about 60–90 °C during Middle to Late Triassic, the palaeo-water was enriched in Sr released from the transformation of precursor aragonite and calcite to dolomite, resulting in precipitation of substantial pre-bitumen Sr-rich minerals (SrSO4 and SrCO3). For un-dolomitized limestone sections, aragonite neomorphism may have contributed Sr to the precipitation of small amounts of Sr-bearing minerals and calcite crystals with elevated homogenization temperatures (HTs, mainly from 90 to 130 °C) and wide Sr contents (from 34 to 3825 ppm), as recorded in stage III calcite. Since the Middle Jurassic, almost all of the early stage celestite and significant amounts of solid CaSO4 have been consumed by reactions with hydrocarbons (i.e., TSR), resulting in water enriched in isotopically light CO2 and HCO3-,Sr2+,Ba2+ and Eu2+, as recorded in calcite with low ?13C values (down to ?18.9‰), 87Sr/86Sr ratios from 0.7072 to 0.7076, high HTs (mainly 110–198 °C), positive Eu anomalies and high Sr and Ba contents. Subsequently, the water was uplifted and cooled down to about 115 °C, celestite and strontianite were precipitated with the occurrence of natural elemental S immiscible inclusions. TSR may have produced significant amounts of freshwater, which brought down Sr concentrations and salinities of the palaeo-waters to not more than about 6.0 wt.% NaCl equivalent.

2012-12-01

124

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 (sour while the Lower Triassic gas tends to be most sour. The elevated H2S (up to 62%) is due to thermochemical sulphate reduction with the most sour Triassic and Permian reservoirs being deeper than 4800 m. The non-TSR affected Carboniferous gas is a secondary gas that was derived from the cracking of sapropelic kerogen-derived oil and primary gas and is highly mature. Carboniferous (and non-sour Triassic and Permian) gas has unusual carbon isotopes with methane and propane being isotopically heavier than ethane (a reversal of typical low- to moderate-maturity patterns). The gas in the non-sour Triassic and Permian reservoirs has the same geochemical and isotopic characteristics (and therefore the same source) as the Carboniferous gas. TSR in the deepest Triassic reservoirs altered the gas composition reaching 100% dryness in the deepest, most sour reservoirs showing that ethane and propane react faster than methane during TSR. Ethane evolves to heavier carbon isotope values than methane during TSR leading to removal of the reversed alkane gas isotope trend found in the Carboniferous and non-sour Triassic and Permian reservoirs. However, methane was directly involved in TSR as shown by the progressive increase in its carbon isotope ratio as gas souring proceeded. CO2 increased in concentration as gas souring proceeded, but typical CO2 carbon isotope ratios in sour gases remained about -4‰ V-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

125

Early Permian post-glacial bivalve faunas of the Itararé Group, Paraná Basin, Brazil: Paleoecology and biocorrelations with South American intraplate basins  

Science.gov (United States)

The uppermost portion of the Taciba Formation, Itararé Group, Paraná Basin, Brazil, records a succession of depositional environments tied to the demise of late Paleozoic glaciation. In the study area, Teixeira Soares county, state of Paraná, the unit is dominated by massive to laminated diamictites with inclusions of sandstones and other coarse-grained lithotypes, representing re-sedimented material in proximal areas. These are succeeded by fine to medium-grained sandstones with tabular cross-stratification and pectinid-rich shell pavements, interpreted as nearshore deposits. Above this, laminated and intensely bioturbated siltstones with closed articulated bivalve shells are recorded, probably deposited in inner shelf settings. Fine to very fine sandstones/siltstones with hummocky cross-stratification and intercalated mudstones, including infaunal in situ shells, are interpreted as stacked storm deposits, generated in distal shoreface environments. These are succeeded by fossil-poor, massive to laminated siltstones/mudstones or gray shales (=Passinho shale) that are inferred to be outer shelf deposits, generated in organic-rich, oxygen-deficient muddy bottoms. In this sedimentary succession dropstones or ice-rafted debris are missing and locally the Passinho shale marks the maximum flooding surface of the Itararé succession. These are capped by the fluvio-deltaic deposits of the Rio Bonito Formation (Sakmarian-Artinskian). Six facies-controlled, bivalve-dominated assemblages are recognized, representing faunal associations that thrived in aerobic to extreme dysaerobic bottoms along a nearshore-offshore trend. Within these assemblages, nineteen bivalve species (three of them new) were recorded and described in detail. The presence of Myonia argentinensis (Harrington), Atomodesma (Aphanaia) orbirugata (Harrington) and Heteropecten paranaensis Neves et al. suggests correlation with bivalve assemblages of the Eurydesma-bearing Bonete Formation, Pillahuincó Group, Sauce Grande-Colorado Basin (Buenos Aires Province), Argentina, indicating a possible Asselian age for this diverse post-glacial bivalve fauna. Despite that, typical members of the icehouse-style Eurydesma-Trigonotreta biota (stricto sensu) have not yet been found in the studied bivalve assemblages.

Neves, Jacqueline Peixoto; Anelli, Luiz Eduardo; Simões, Marcello Guimarães

2014-07-01

126

Paleomagnetic and (40)Ar/(39)Ar Results from the Grant Intrusive Breccia and Comparison to the Permian Downeys Bluff Sill. Evidence for Permian Igneous Activity at Hicks Dome, Southern Illinois Basin.  

Science.gov (United States)

Studies of igneous rocks in southern Illinois contribute to multidisciplinary investigations of the thermal activity, fluid-flow history, hydrocarbon generation, and mineralizatin in and around the Illinois Basin. In this study, we apply 40Ar/39Ar dating ...

R. L. Reynolds M. B. Goldhaber L. W. Snee

1997-01-01

127

Permian and uranium metallogeny  

International Nuclear Information System (INIS)

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

1990-01-01

128

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  

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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

129

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

2010-07-01

130

Palaeozoic nonmarine firmground ichnofaunas: Evidence from the permian of the Paganzo basin [Icnofaunas paleozoicas en sustratos firmes no marinos: Evidencias del pe??rmico de la cuenca Paganzo  

Science.gov (United States)

Meniscate striated traces are recorded from Permian fluvial deposits of the La Colina Formation (Paganzo Group) at Los Colorados de Patqui??a (La Rioja Province). These structures are characterized by their remarkable well developed striations, oblique to the margins of unbranched and unwalled traces. Taxonomic assessment of these structures must await clarification of the actual nature of the ichnogenus Scoyenia and its relationship with Taenidium. They are interpreted as arthropod feeding structures (fodinichnia). Meniscate striated traces characterize firm substrates and crosscut a softground ichnofauna ascribed to the Scoyenia ichnofacies. Trace makers probably colonized the desiccated margins of a floodplain water body. A review of the ichnologic record of nonmarine firmgrounds shows the widespread establishment of trace fossils in cohesive sediments during the Mesozoic and only an incipient development during the Palaeozoic. The Palaeozoic examples undoubtely ascribed to invertebrates are known from the Permian and seem to record the displacement of organisms in the interface of a firm substrate, rather than burrowing activities within the cohesive sediment.

Buatois, L. A.; Mangano, M. G.; Acenolaza, F. G.

1996-01-01

131

Central Antarctic provenance of Permian sandstones in Dronning Maud Land and the Karoo Basin: Integration of U Pb and TDM ages and host-rock affinity from detrital zircons  

Science.gov (United States)

In conjugate SE Africa and Antarctica, Early Permian sandstones of the Swartrant Formation of the Ellisras Basin, Vryheid Formation of the Karoo Basin, and Amelang Plateau Formation of Dronning Maud Land (DML) were deposited after Gondwanan glaciation on a westward paleoslope. We analysed detrital zircons for U-Pb ages by a laser ablation microprobe-inductively coupled plasma mass spectrometer (LAM-ICPMS) and attached age significance only to clusters of three or more overlapping analyses. We analysed Hf-isotope compositions by a multi-collector spectrometer (LAM-MC-ICPMS) and trace elements by electron microprobe (EMP) and ICPMS. These analyses indicate the rock type and source (whether crustal or juvenile mantle) of the host magma, and a "crustal" model age ( TDMC). The integrated analysis gives a more distinctive, and more easily interpreted, picture of crustal evolution in the provenance area than age data alone. Zircons from the Ellisras Basin are aged 2700-2540 Ma with minor populations about 2815 Ma and 2040 Ma, which correspond with the ages of the upslope parts of the proximal Kaapvaal Craton and Limpopo Belt. Mafic rock is the dominant host rock, and it reflects the Archean granite-greenstone terrane of the Kaapvaal Craton. The three Karoo Basin samples and the two DML samples have zircons with these common properties: (1) 1160-880 Ma, host magma mafic granitoid (Australia, these properties reflect those in upslope central Antarctica, indicating a provenance of ˜ 1000 Ma (Grenville) cratons embedded in 700-500 Ma (Pan-Gondwanaland) fold belts. Detrital zircons in Cambrian sediments of the Ellsworth-Whitmore Mountains block and Cambrian metasediments of the Welch Mountains with comparable properties suggest that the central Antarctic provenance operated also in the ˜ 500 Ma Cambrian.

Veevers, J. J.; Saeed, A.

2007-12-01

132

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

2004-09-01

133

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

134

Upper permian foraminifera from East Greenland  

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Foraminiferal assemblages recorded from limestones of the Upper Permian Wegener Halvoe Formation in the Wegener Halvoe, Karstryggen and Clavering Oe areas of East Greenland mostly consist of the nodosariid genera Dentalina, Frondina, Geinitzina and Ichtyolaria, and the miliolid genera Agathammina nd Calcitornella. More limited assemblages dominated by Agathammina were recorded from the underlying Karstrygen Formation. The foraminifera are all benthonic, mostly shallow-water forms. The fauna is of Zechstein aspect and suggests a broad correlation with Zechstein 1 and younger strata in the Zechstein basin of North-West Europe. Solid specimens of agglutinated foraminifera, mostly referable to Ammobaculites and Ammodiscus, were recorded from the youngest Permian strata, The Schuchert Dal Formation, in the Schuchert Dal. (au) 32 refs.

Pattison, J. [Loughborough Road, West Brigford, Nottingham (United Kingdom); Stemmerik, L. [Geological Survey of Denmark and Greenland, Copenhagen (Denmark)

1996-12-31

135

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

2011-12-01

136

The Major-ion Composition of Permian Seawater  

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The major-ion (Mg{sup 2+}, Ca{sup 2+}, Na{sup +}, K{sup +}, SO{sub 4}{sup 2-}, and Cl{sup -}) composition of Permian seawater was determined from chemical analyses of fluid inclusions in marine halites. New data from the Upper Permian San Andres Formation of Texas (274--272 Ma) and Salado Formation of New Mexico (251 Ma), analyzed by the environmental scanning electron microscopy (ESEM) X-ray energy-dispersive spectrometry (EDS) method, along with published chemical compositions of fluid inclusions in Permian marine halites from North America (two formations of different ages) and the Central and Eastern European basins (eight formations of four different ages) show that Permian seawater shares chemical characteristics with modern seawater, including SO{sub 4}{sup 2-} > Ca{sup 2+} at the point of gypsum precipitation, evolution into Mg{sup 2+}-Na{sup +}-K{sup +}-SO{sub 4}{sup 2-}-Cl{sup -} brines, and Mg{sup 2+}/K{sup +} ratios {approx} 5. Permian seawater, however, is slightly depleted in SO{sub 4}{sup 2-} and enriched in Ca{sup 2+}, although modeling results do not rule out Ca{sup 2+} concentrations close to those in present-day seawater. Na{sup +} and Mg{sup 2+} in Permian seawater are close to (slightly below) their concentrations in modern seawater. Permian and modern seawater are both classified as aragonite seas, with Mg{sup 2+}/Ca{sup 2+} ratios >2, conditions favorable for precipitation of aragonite and magnesian calcite as ooids and cements. The chemistry of Permian seawater was modeled using the chemical composition of brine inclusions for three periods: Lower Permian Asselian-Sakmarian (296--283 Ma), Lower Permian Artinskian-Kungurian (283--274 Ma), and Upper Permian Tatarian (258--251 Ma). Parallel changes in the chemistry of brine inclusions from equivalent age evaporites in North America, Central Europe, and Eastern Europe show that seawater underwent secular variations in chemistry over the 50 million years of the Permian. Modeled SO{sub 4}{sup 2-} concentrations are 20 mmol per kg H{sub 2}O (mmolal) and 19 mmolal in the Asselian-Sakmarian and Artinskian-Kungurian, with higher concentrations in the Upper Permian Tatarian (23 mmolal). Modeled Ca{sup 2+} is at or above its concentration in modern seawater throughout the Permian. Mg{sup 2+} is close to (slightly below) its concentration in modern seawater (55 mmolal) in the Asselian-Sakmarian (52 mmolal), and Tatarian (52 mmolal), but slightly higher than modern seawater in the Artinskian-Kungurian (60 mmolal). Mg{sup 2+}/Ca{sup 2+} ratios are 3.5 (total range = 2.7 to 5.5) in the Lower Permian and rose slightly to 3.7 (total range = 3.1 to 5.8) in the Upper Permian, primarily due to decreases in Ca{sup 2+}. These results are consistent with models that predict oscillations in the major-ion composition of Phanerozoic seawater on the basis of changes in the midocean ridge/river water flux ratio driven by changes in the rate of midocean ridge crust production. The Permian was characterized by low sea levels, icehouse conditions, and southern hemisphere glaciation. Such conditions, analogous to the present ice age, and the similarities between Permian seawater and modern seawater, all suggest that general Phanerozoic supercycles, driven by mantle convection and global volcanicity, also control the major-ion chemistry of seawater.

Lowenstein, T K. [State University of New York, Binghamton; Timofeeff, Michael N. [State University of New York, Binghamton; Kovalevych, Volodymyr M. [National Academy of Sciences of Ukraine, Naukova, Ukraine; Horita, Juske [ORNL

2005-01-01

137

Sill-induced evaporite- and coal-metamorphism in the Tunguska Basin, Siberia, and the implications for end-Permian environmental crisis  

Science.gov (United States)

The emplacement of the Siberian Traps Large igneous province is regarded as the main processes behind the end-Permian environmental crisis. The details of this link are however still under investigation. Among the suggestions are lava degassing of mantle- and crustal-derived gases, explosive lava and phreatomagmatic eruptions, and gas release from contact metamorphism related to the sub-volcanic sill complex. Whereas the lava pile is relatively well studied and investigated, the sub-volcanic sills, dikes, and contact aureoles are poorly studied and documented. We present borehole and field data of sills and contact aureoles from across the Siberian Traps, from Norilsk in the north to Bratsk in the south. The data have been compiled during three field campaigns in 2004, 2006, and 2010. The sill geometries and thicknesses vary considerably from kilometer-scale intrusive complexes to individual thin sills of a few tens of meters. In contrast to several other LIPs, sills are also emplaced within the extrusive pile. Thick sills (up to 900 meters in thickness) occur in high abundance in the upper part of the sedimentary succession, affecting the coal-rich Tungusska Series sediments. Moreover, very thick sills (100-300 meters) are also emplaced within the vast Cambrian salt formations. Petrographic investigations of the metamorphic sediments demonstrate that widespread high temperature devolatilization took place. We show that depending on the specific location within the province and the emplacement depth, the potential for degassing of both greenhouse gases (CH4, CO2), aerosols (SO2), and ozone destructive gases (CH3Cl, CH3Br) was substantial and can explain the crisis.

Svensen, Henrik; Polozov, Alexander G.; Planke, Sverre

2014-05-01

138

Characterization of an Upper Permian Tight Gas Reservoir : a multidisciplinary, multiscale analysis from the Rotliegend, Northern Germany  

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This thesis describes a multidisciplinary, multiscale approach to the analysis of tight gas reservoirs. It focused initially on the facies architecture of a Permian tight gas field in the Southern Permian Basin (SPB), East Frisia, Northern Germany. To improve field development, 3D seismic data, wireline and core data were compared to a reservoir analogue in the Panamint Valley, California, United States. Depositional environments of the Permian Upper Rotliegend II included perennial saline la...

Antrett, Philipp

2011-01-01

139

The siliciclastic Permian-Triassic deposits in Central and Northeastern Iberian Peninsula (Iberian, Ebro and Catalan Basins): a proposal for correlation  

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The siliciclastic deposits of the Iberian, Ebro and Catalan Basins have been described for more than a century, but facies similarities and a lack of biostratigaphic data have difficulted the correlation of the local stratigraphic units in a general framework up to now. Combining pollen and spores data, the identification of the regional unconformities and hiatuses and the quantitative analysis of the subsidence by backstripping methods, a new correlation scheme for these facies is proposed.

Arche, A.

2004-01-01

140

Strontium Isotopes as a Geochemical Tracer for the Evolution of Brines in Permian Evaporite Deposits of the Central European Basin, Germany  

Science.gov (United States)

Seepages of formation water into salt mines bear the potential of flooding. This hazard poses a high risk for the salt mining industry all over the world. Recent tests of water draining drillholes into the enclosing bedrock of a salt dome in northern Germany have been performed. These tests show good results in reducing the inflow rate of the formation water into the mine openings. The risk of weakening the salt flank due to drilling activities increases the potential for inflow. Hence, the specific source of the intrusion has to be localized to minimize the number of drillholes. Former studies determined the stable isotopes ?D and ?18O to be the most suitable isotopic tracers for concentrated saline solutions. We have applied Sr isotopes as an additional tool to further define the source. Sr isotope compositions and concentrations will be monitored over the following years to detect possible time-dependent fluctuations. Recent preliminary Sr analyses of one brine inflow in a potash mine in the upper Permian Zechstein series, Germany, show a trend for Sr to be extracted from detritus of salt clay layers, which are intercalated in a sequence of rock salt with anhydrites. This clayey material shows the highest 87Sr/86Sr ratios of the whole sequence, however, still lower than the formation water which has been discharged from the superimposed Triassic (Buntsandstein). We assume for these preliminary data that during migration, the solution increases its moderate Sr concentration by first solving the anhydrite layer at the margin of the salt dome. The saline solution then drains through the rock salt sequence. In this part, mainly the salt clay layers seem to be leached, probably due to the very low pH of the brine. The final solution has a Sr concentration that is about 3.5 times higher than in the formation water, but the 87Sr/86Sr ratio is almost the same. These preliminary data suggest that the Sr isotope composition is rather affected by the salt clay detritus than by halite or anhydrite. Therefore, we may be able to further delimit the source regions of intruding formation waters.

Klaus, J. S.; Hansen, B. T.; Beer, W. W.

2005-12-01

 
 
 
 
141

Permian karst topography in the Wichita uplift, southwestern Oklahoma  

Energy Technology Data Exchange (ETDEWEB)

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

142

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

143

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

144

Regional structural cross sections, mid-permian to quaternary strata, Texas Panhandle and Eastern New Mexico  

Energy Technology Data Exchange (ETDEWEB)

Twelve regional cross sections (with text) of the Palo Duro, Dalhart, and Anadarko Basins illustrating the tabular geometry of Permian evaporite beds, areas where salt has been lost by dissolution, and the effects of dissolution-induced subsidence on Permian and post-Permian strata. The authors identify areas of dissolution beneath the High Plains, the Caprock Escarpment, the Rolling Plains, the Pecos Plains, and along the Canadian River valley. The cross sections are printed at a vertical scale of 1 inch equals 400 feet and a horizontal scale of 1 inch equals approximately 8 miles and were constructed using geophysical logs, sample logs, and surficial geologic data.

McGookey, D.A.; Gustavson, T.C.; Hoadley, A.D.

1989-01-01

145

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

146

Upper Permian fluviolacustrine deposits of southern Africa and the late Permian climate southern Gondwana  

Energy Technology Data Exchange (ETDEWEB)

Upper Permian-age fluviolacustrine deposits are widespread throughout southern Africa. In the southern part of the subcontinent, where deposition took place in foreland basin settings, the sequences are thicker and fluvial-dominated whereas, lacustrine-dominated deposits accumulated in settings of low relief, broad warping and mild faulting at the northern end. The geographic extent and lateral correlatability of these deposits suggest the existence of concurrent, perhaps interconnected, giant lakes within major fluvial frameworks throughout the subcontinent, thousands of miles inland from the sea. This period of major lake development within fluvial depositional settings suggests climatic conditions that sustained a uniquely wet continental environment, deep in the heart of the Gondwanan supercontinent. Simulations based on various general circulation and energy balance climate models predict extreme seasonal temperatures and aridity for Gondwana at the palaeolatitudes of southern Africa during the Late Permian. On the other hand, distribution of climate-sensitive rocks, palynologic and palaeobotanic data and vertebrate fossils, coroborate the temperature climate documented by sedimentologic studies. The erroneous modeling results may have arisen from the fact that the models do not employ palaeogeographies that accommodate the existence of the vast lakes and rivers of Gondwana. The Late Permian palaeogeography of series of giant lakes within major fluvial frameworks would have had considerable influences on the regional climate. This suggests that it is imperative that numerical modeling studies incorporate accurate palaeogeographies, constructed based on available geological data, in order to recreate past climates with acceptable degree of accuracy.

Yemane, K. (Univ. of Pennsylvania, Philadelphia, PA (United States). Dept. of Geology Bryn Mawr Coll., PA (United States). Dept. of Geology)

1993-03-01

147

Permian magmatism, Permian detachment faulting, and Alpine thrusting in the Orobic Anticline, southern Alps, Italy  

Science.gov (United States)

The Grassi Detachment Fault is located in the Orobic Alps east of Lake Como and was described by Froitzheim et al. (2008) as an Early Permian extensional structure. Many issues still remained unclear, like the exact timing of faulting and the extension from the well-exposed part of the detachment towards west. The Grassi Detachment Fault separates the Variscan Basement in its footwall from the volcanic and sedimentary rocks of the Early Permian Collio Formation within its hanging wall, marked by a mylonitic and cataclastic layer whose textures indicate top-to-the-southeast displacement. The footwall basement is formed by the Variscan Morbegno Gneiss and two granitic intrusions, the Val Biandino Quarz Diorite (VBQD) and the Valle Biagio Granite (VBG). The former is syntectonic with respect to the detachment, whereas for the latter, the relation to the detachment is unknown. The age of the VBQD is poorly defined as 312 Ma ± 48 Ma (Thöni et al. 1992); the VBG has not been dated. Volcanic rocks of the Collio Formation in the hanging wall may represent the extrusive part of the magmatic system. In our study area west of Val Biandino, several faults and shear zones are exposed: (1) The Grassi Detachment Fault is represented by mylonites and cataclasites with top-SE shear sense, between basement rocks and the Collio Volcanics. Towards NW, it is truncated by the unconformably overlying Late Permian Verrucano Lombardo. This may reflect the eroded culmination of a Permian metamorphic core complex. (2) A steeply NW-dipping, brittle normal fault is found further west in the footwall between VBQD and VBG. It is sealed by the basal unconformity of the Verrucano Lombardo and therefore should also be of Early Permian age (Sciunnach, 2001). It may represent an antithetic fault with respect to the detachment, accommodating the uplift of the magmatically inflated core complex. (3) The Biandino Fault is a steeply SE-dipping reverse fault, affecting also the Late Permian Verrucano Lombardo. It is therefore an Alpine structure. (4) Several south-directed Alpine thrusts duplicate the lithostratigraphy, including the detachment, and are related to the Orobic thrust further north. They also offset the Biandino Fault. U-Pb zircon ages measured with LA-ICP-MS (work in progress) will further clarify the temporal relations between the intrusions, volcanics, and the shear zones. Froitzheim, N., Derks, J.F., Walter, J.M. & Sciunnach, D. 2008. Evolution of an Early Permian extensional detachment fault from synintrusive, mylonitic flow to brittle faulting (Grassi Detachment Fault, Orobic Anticline, southern Alps, Italy) Geological Society, London, Special Publications, 298; 69-82. doi:10.1144/SP298.4 Thöni, M., Mottana, A., Delitala, M. C., De Capitani, L. & Liborio, G. 1992. The Val Biandino composite pluton: A late Hercynian intrusion into the South-Alpine metamorphic basement of the Alps (Italy). Neues Jahrbuch für Mineralogie-Monatshefte, 12, 545-554. Sciunnach, D. 2001. Early Permian palaeofaults at the western boundary of the Collio Basin (Valsassina, Lombardy). Natura Bresciana. Annuario del Museo Civico di Scienze Naturali, Brescia, Monografia, 25, 37-43.

Pohl, Florian; Froitzheim, Niko; Geisler-Wierwille, Thorsten; Schlöder, Oliver

2014-05-01

148

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,

1995-06-01

149

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

150

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, at familiar and generic levels, through three time intervals, i.e., Early Carboniferous (Tournaisian-Visean), Late Carboniferous (Bashkirian-Kasimovian) and Early Permian (Asselian-Sakmarian), ...

Fabiana Sterren, Andrea

2010-01-01

151

International correlation of Early Permian palynofloras from the Karoo sediments of Morupule, Botswana  

Energy Technology Data Exchange (ETDEWEB)

This paper is the first published account of Palaeozoic palynological assemblages from Botswana. Palynological assemblages of the lower Karoo Morupule Main Seam of the Morupule Colliery in Botswana are similar to those of the Striatopodocarpites fusus Biozone of the Collie Basin, Western Australia and the 3a Microfloral Biozone of the northern Karoo Basin, South Africa. This indicates an Aktastinian (Early Permian) age for the strata of Morupule. 34 refs., 7 figs., 1 tab.

Stephenson, M.H.; McLean, D. [University of Sheffield, Sheffield (United Kingdom). Dept. of Earth Sciences

1999-03-01

152

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

153

Parana basin  

Energy Technology Data Exchange (ETDEWEB)

The Parana basin is a large intracratonic basin in South America, developed entirely on continental crust and filled with sedimentary and volcanic rocks ranging in age from Silurian to Cretaceous. It occupies the southern portion of Brazil (1,100,000 km/sup 2/ or 425,000 mi/sup 2/) and the eastern half of Paraguay (100,000 km/sup 2/ or 39,000 mi/sup 2/); its extension into Argentina and Uruguay is known as the Chaco-Parana basin. Five major depositional sequences (Silurian, Devonian, Permo-Carboniferous, Triassic, Juro-Cretaceous) constitute the stratigraphic framework of the basin. The first four are predominantly siliciclastic in nature, and the fifth contains the most voluminous basaltic lava flows of the planet. Maximum thicknesses are in the order of 6000 m (19,646 ft). The sequences are separated by basin wide unconformities related in the Paleozoic to Andean orogenic events and in the Mesozoic to the continental breakup and sea floor spreading between South America and Africa. The structural framework of the Parana basin consists of a remarkable pattern of criss-crossing linear features (faults, fault zones, arches) clustered into three major groups (N45/sup 0/-65/sup 0/W, N50/sup 0/-70/sup 0/E, E-W). The northwest- and northeast-trending faults are long-lived tectonic elements inherited from the Precambrian basement whose recurrent activity throughout the Phanerozoic strongly influenced sedimentation, facies distribution, and development of structures in the basin. Thermomechanical analyses indicate three main phases of subsidence (Silurian-Devonian, late Carboniferous-Permian, Late Jurassic-Early Cretaceous) and low geothermal gradients until the beginning of the Late Jurassic Permian oil-prone source rocks attained maturation due to extra heat originated from Juro-Cretaceous igneous intrusions. The third phase of subsidence also coincided with strong tectonic reactivation and creation of a third structural trend (east-west).

Zalan, P.V.; Wolff, S.; Conceicao, J.C.J.; Vieira, I.S.; Astolfi, M.A.; Appi, V.T.; Zanotto, O.; Neto, E.V.S.; Cerqueira, J.R.

1987-05-01

154

The last "pelycosaur": a varanopid synapsid from the Pristerognathus Assemblage Zone, Middle Permian of South Africa.  

Science.gov (United States)

We report on a partial varanopid skull and mandible from the Pristerognathus Assemblage Zone of the Beaufort Group, in the South African Karoo Basin, which is probably latest Middle Permian (Capitanian) in age. This mycterosaurine is not only the youngest known varanopid from the Southern Hemisphere, but it is also the youngest known "pelycosaur" (i.e., non-therapsid synapsid). Like all other members of this clade of hypercarnivores, the teeth are strongly flattened, recurved, and have finely serrated cutting edges. The anterior dentary teeth form a caniniform region, and the splenial features a foramen intermandibularis oralis, the first ever to be described in a "pelycosaur." The last varanopids were the smallest carnivores of latest Middle Permian continental faunas. Occupation of the small carnivore guild appears to have allowed varanopids to achieve a nearly cosmopolitan distribution throughout the Middle Permian, between the great Early Permian radiation of basal synapsids and the spectacular diversification of therapsid synapsids in the Late Permian and Early Triassic. PMID:22009069

Modesto, Sean P; Smith, Roger M H; Campione, Nicolás E; Reisz, Robert R

2011-12-01

155

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 â??Skagerrak-Centered Large Igneous Provinceâ? 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

156

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

157

Structure and depositional environments of Permian-Triassic terrigeneous complex of the Barents Sea shelf  

Science.gov (United States)

Permian-Triassic complex of the Barents Sea shelf composed of up to 8-12 km of clastic sediments has a great interest for geology as it contains hydrocarbon-bearing reservoirs and source rocks. It is drilled on shelf margins and structural highs; it outcrops in adjoining archipelagos. However within depositional centers like the South-Barents basin where Permian-Triassic reaches maximum thickness and burial, its structure can only be understood from seismic data. We present an evaluation of structure, depositional environments and cyclicity of Permian-Triassic terrigeneous complex based on interpretation of 18 000 km of regional seismic profiles with record length of 10-12 s acquired by MAGE in 2007-09 in the south-east shelf. Transgressive-regressive sequences were identified and correlated using well log analysis for 17 wells, descriptions of well sections and outcrops in Franz Josef Land, Svalbard and Novaya Zemlya archipelagos. Cooling of the climate throughout Sakmarian-Artinskian (Lower Permian), marine transgression, and Ural orogeny in the south-east had interrupted carbonate deposition and initiated the deposition of terrigeneous (East Barents) and spiculite, siliceous-carbonate, and siliciclastic (West Barents) sediments (Geological history, 2009). Triassic is represented by clastic lithologies all over the basin. On seismic data lower boundary of Permian-Triassic complex is a high-amplitude reflector (Ia) and downlap surface corresponding to the top of Lower Permian carbonates. Upper boundary is related to Rhaetian erosional unconformity best pronounced in the pre-Novaya Zemlya foredeep, Kola monocline and Pechora Sea. Permian is represented by 5 transgressive-regressive sequences with upward regressive trend and total thickness of 100-800 m. Low-angle clinoforms prograding from south-east (Ural provenance) and east were interpreted on seismic. Increasing thickness of Permian towards Novaya Zemlya is consistent with up to 4 km of sediments in the archipelago's outcrops and indicates Kara provenance. In the south-eastern basin margin Permian-Triassic boundary is well-traced due to its erosional origin and downlapping of overlaying Induan clinoforms. Triassic sediments were formed in deltaic, shallow-marine to deep shelf environments in the large epicontinental basin with vast transgressions and significant lateral shift of the shoreline during sea level changes. Interpreted Triassic horizons correspond to Induan/Olenekian (top Havert), Lower/Upper Olenekian, Olenekian/Anisian (top Klappmyss) and Ladinian/Carnian boundaries. These relatively continuous reflectors were formed as transgressive shaly packages overlaid sequence boundaries. During Induan clinoforms (height ~100 s) had prograded to the north-west and west compensating the steady subsidence of the South- and North Barents depressions and pre-Novaya Zemlya foredeep. We traced migration of the clinoform break (platform margin) of several Induan prograding sequences across the South-Barents basin towards Norwegian Barents Sea, where the area of non-compensated deposition in deep shelf environments was delineated (Glorstad-Clark, 2010). During Olenekian and Middle Triassic the clinoform break persisted in the western shelf, thus no clinoforms are observed in the south-east of the Barents Sea where deltaic environments had prevailed. Late Triassic was characterized by shallowing of the basin, spreading of deltas and filling of previously non-compensated area in the north-west. Maximum thickness of Triassic is related to Lower Triassic within South Barents basin and Lower-Middle Triassic within the pre-Novaya Zemlya foredeep.

Norina, Daria; Stoupakova, Antonina

2014-05-01

158

Permian Gondwana sedimentation in Yellandu (Singareni) coalfield, Andhra Pradesh, India with notes on regional paleogeography and tectonic history  

Energy Technology Data Exchange (ETDEWEB)

The Yellandu coalfield of Andhra Pradesh contains 850 m Permian Gondwana rocks composed of Barakar, Barren Measures and Raniganj Formations. They are characterised by fining upward cycles. The sandstones are channel shaped, sheet-like and multistoried, and planar and trough cross bedded. The shales are massive to laminated and form thin tenses in the Barakar, but moderately thick sheets in the overlying Barren Measures and Raniganj Formations. The coal seams are thin and lensoid. Paleocurrent studies suggest consistently northwesterly dispersal direction areally and temporally. Evidence indicates that initially braided streams at the onset of Early Permian Barakar sedimentation became meandering through into Barren Measures and Raniganj Formations of Middle and Late Permian, respectively. The close similarity in lithofacies depositional environment and dispersal direction of Permian rocks of Yellandu coalfields and those of neighbouring Pranhita-Godavari basin in the east, and their geological and tectonic setting suggest that the Yellandu coalfield was part of the Godavari basin until the Late Permian or Early Triassic.

Tewari, R.C. [Aligarh Muslim University, Aligarh (India). Dept. of Geology

1998-11-01

159

Stratigraphy of the Carboniferous-Permian volcanosedimentary sequences of the Northern Pamir, Tajikistan  

Science.gov (United States)

The point of view on two angular unconformities in the section of the Lower Carboniferous volcanosedimentary sequences of the northern Pamir is disproved. Two terrigenous sequences in contrast to one Beleuli sequence of shales are present in the Beleuli River basin. The first Carboniferous sequence conformably overlaps limestones with Serpukhovian goniatites and the second Permian sequence may be correlated with the Pshikharv Formation of shales from the western regions of the northern Pamir and contacts by the thrust Carboniferous rocks.

Leven, E. Ja.

2013-11-01

160

Impacts of Siberian Trap Eruption on NW Pangea during the Latest Permian Extinction (Invited)  

Science.gov (United States)

The Sverdrup Basin, Canadian High Arctic, was located on the NW margin of Pangea during the Latest Permian Extinction. Strong mid-latitude westerly winds would have transported stratospheric ash clouds from Siberian Trap eruptions to the Sverdrup Basin, making it one of the best localities to examine impacts on marine systems. Three layers of organic rich shale, immediately below the Latest Permian Extinction boundary, are dominated by combustion-derived isotropic chars with optical properties that indicate intense, high temperature carbonization and rapid combustion of organic material that can not be associated with burial-related thermal maturation. These particles are consistent however with coal fly-ash suggesting significant loading of coal ash occurred just prior to the mass extinction. Deposition of coal combustion products could have had multiple deleterious affects including nutrient loading, light limitation, and release of toxic elements to marine systems. Loading events of toxic elements commonly associated with coal (e.g. Cr), are found associated with fly-ash layers. The Sverdrup Basin also records significant Hg anomalies associated with the Latest Permian Extinction, including a breakdown of the normal marine process of organic matter mediated Hg drawdown. High Hg loading rates are interpreted to be associated with the mega-eruption event of the Siberian Traps as volcanoes are the largest source of mercury in the natural Hg cycle.

Grasby, S. E.; Sanei, H.; Beauchamp, B.

2013-12-01

 
 
 
 
161

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

162

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  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

2010-01-01

163

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 SciELO Argentina | Language: Portuguese 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 fo [...] i 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 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 in 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..

164

Provincialization of terrestrial faunas following the end-Permian mass extinction  

Science.gov (United States)

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, Christian A.; Vilhena, Daril A.; Angielczyk, Kenneth D.; Huttenlocker, Adam K.; Nesbitt, Sterling J.; Peecook, Brandon R.; Steyer, J. Sebastien; Smith, Roger M. H.; Tsuji, Linda A.

2013-01-01

165

Amphibian and Paleoisciforms from the Lower Part of the Taquaral Member of the Permian Irati Formation, São Paulo State, Brazil  

Directory of Open Access Journals (Sweden)

Full Text Available In the east-central region of the State of São Paulo, Brazil, good exposures of Permo-Carboniferous sequences of theParaná intracratonic basin are found. These sequences start with the Tubarão Supergroup deposits, the PermocarboniferousItararé Group, and the earliest Permian Guatá Group, of which the Tatuí Formation is the only unit occurring in the Stateof São Paulo. The Permian Passa Dois Group overlies the Tubarão Supergroup, with the Early Permian Irati Formation andthe Middle Permian Corumbataí Formation. Two members are recognized in the Irati Formation, Taquaral and Assistência.Most beds of the Taquaral Member are gray laminated siltic-argillaceous, but sandstone beds are present in lower outcropsof this member. One of these sandstones, 9.5 cm thick unconformably overlying sedimentos of the Tatuí Formation, exhibitsdiversifi ed vertebrate remains. The present paper deals with a Palaeonisciformes mandible fragment, one amphibianTemnospondyli tooth, and one Temnospondyli mandible fragment. These fossils are associated to Chondrichthyes andOsteichthyes. It is an open question whether the Parnaíba Basin Palaeonisciformes Brasilichthys macrognathus and theTemnospondyli Prionosuchus plummery belong to the same taxa of the Paraná Basin fossils. Only better preserved fossilsmight solve this question.

Artur Chahud

2010-03-01

166

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  

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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

167

From wetlands to wet spots: Environmental tracking and the fate of carboniferous elements in early permian tropical fl oras  

Science.gov (United States)

Diverse wetland vegetation flourished at the margins of the Midland Basin in north-central Texas during the Pennsylvanian Period. Extensive coastal swamps and an ever-wet, tropical climate supported lush growth of pteridosperm, marattialean fern, lycopsid, and calamite trees, and a wide array of ground cover and vines. As the Pennsylvanian passed into the Permian, the climate of the area became drier and more seasonal, the great swamps disappeared regionally, and aridity spread. The climatic inferences are based on changes in sedimentary patterns and paleosols as well as the general paleobotanical trends. The lithological patterns include a change from a diverse array of paleosols, including Histosols (ever-wet waterlogged soils), in the late Pennsylvanian to greatly diminished paleosol diversity with poorly developed Vertisols by the Early-Middle Permian transition. In addition, coal seams were present with wide areal distribution in the late Pennsylvanian whereas beds of evaporates were common by the end of the Early Permian. During this climatic transition, wetland plants were confi ned to shrinking "wet spots" found along permanent streams where the vegetation they constituted remained distinct if increasingly depauperate in terms of species richness. By Leonardian (late Early Permian) time, most of the landscape was dominated by plants adapted to seasonal drought and a deep water table. Wetland elements were reduced to scattered pockets, dominated primarily by weedy forms and riparian specialists tolerant of flooding and burial. By the Middle Permian, even these small wetland pockets had disappeared from the region. ?? 2006 Geological Society of America.

DiMichele, W. A.; Tabor, N. J.; Chaney, D. S.; Nelson, W. J.

2006-01-01

168

Concealed evaporite basin drilled in Arizona  

Energy Technology Data Exchange (ETDEWEB)

The White Mountains of Arizona are a high forested plateau underlain by volcanic rocks of Late Pliocene and Quaternary age on the south margin of the Colorado plateau province. Elevations range from 6,000--11,590 ft, with winter snow and summer rain but ideal conditions for much of the year. There was no evidence of a Permian evaporite basin concealed beneath the White Mountain volcanic field until 1993, when the Tonto 1 Alpine-Federal, a geothermal test well, was drilled. This test did not encounter thermal waters, but it did encounter a surprisingly thick and unexpected sequence of anhydrite, dolomite, and petroliferous limestone assigned to the Supai (Yeso) formation of Permian age. The Tonto test was continuously cored through the Permian section, providing invaluable information that is now stored at the Arizona Geological Survey in Tucson. The paper describes the area geology and the concealed basin.

Rauzi, S.L. [Arizona Geological Survey, Tucson, AZ (United States)

1996-10-21

169

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

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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.

2001-01-01

170

Acritarchs from the Number 5 Seam in the Permian Vryheid Formation, Witbank Coalfield, South Africa  

Energy Technology Data Exchange (ETDEWEB)

Two species of marine acritarchs, Mehlisphaeridium fibratum and Mehlisphaeridium gondwanaensis, are described from a shale parting near the top of the No. 5 Seam at Greenside Colliery, Witbank Coalfield, Republic of South Africa. The sedimentary sequence containing this coal seam consists of fine- to very coarse-grained sandstone, siltstone, shale, and coal which constitute part of the Early Permian Vryheid Formation (Karoo Supergroup). The paleoenvironmental implications of the discovery of acritarchs imply that marine conditions prevailed in the basin at the time of deposition of this particular shale unit. 56 refs., 6 figs., 1 tab.

Venter, M.E.; Cairncross, B. [Rand Afrikaans University, Auckland Park (South Africa). Dept. of Geology

1995-12-01

171

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

172

Nitrogen Limitation and Productivity in the Permian-Triassic Greenhouse Ocean  

Science.gov (United States)

Marine primary productivity is an important ecological variable with major implications for the end-Permian carbon cycle. While numerous studies have examined relative changes in productivity across the Permian-Triassic boundary, we have less constraint on absolute rates of carbon export from the surface ocean, or qualitative comparison to modern marine environments. The HEATT model suggests that under sufficiently warm conditions, an increase in denitrification and decrease in P burial efficiency could lead to replacement of P by N as the ultimate limiting nutrient in marine systems, although the implications of such limitation on primary productivity are not clear. The Gujo Hachiman and Ubara sections, located in the Mino-Tamba accretionary complex of Japan, record sedimentation in the equatorial Panthalassic ocean across the Permian-Triassic boundary, an interval experiencing potentially the most intense greenhouse conditions of the Phanerozoic. Nitrogen isotope measurements of sedimentary organic matter in the Japanese accreted sections show values consistently close to 0, suggesting that the planktonic ecosystem relied on direct N fixation from the atmosphere by cyanobacteria to supply its nutrient requirements. Calculated organic carbon fluxes are comparable to those seen in the modern equatorial Pacific, however these results are complicated by preservational effects, suggesting an approach that includes several proxies for productivity with different modes of preservation. In this study, we attempt to constrain productivity in the late-Permian/earliest-Triassic equatorial Panthalassic Ocean and make comparisons with analogous environments in the modern equatorial Pacific. We compare calculated mass fluxes of inorganic productivity proxies to the modern equatorial Pacific Ocean, as well as areas of known local N limitation due to denitrification, such as the Cariaco Basin.

Schoepfer, S.; Algeo, T. J.

2013-12-01

173

Recrystallized microbial trace fossils from metamorphosed Permian basalt, southwestern Japan  

Science.gov (United States)

Microbial trace fossils on terrestrial basalts can be used as an analogue in the search for traces of life on other terrestrial planets. This study reports on microbial trace fossils within Permian greenstones in the Maizuru Terrane, southwest Japan, which is recognized as back-arc basin oceanic crust that consists mainly of metabasalt and metagabbro. The trace fossils have been studied by means of morphology, mineralogy, elemental mapping, and carbon isotope analysis. Although minute original textures of trace fossils are recrystallized in these rocks, Granulohyalichnus vulgaris isp., Tubulohyalichnus spiralis isp., and Tubulohyalichnus annularis isp. were identified. Significant concentration of C within the trace fossils implies these are organic remnants from microbes. The ?13CPDB values <-7‰ of calcite within the greenstones indicates that the bacterial activity took place prior to the formation of calcite veins. The results support that microbial trace fossils within low-grade metamorphic basalt can be reliably identified based on their morphology and chemical composition, as reveled by elemental mapping. In this context, glassy Martian basalt may be the best rock type to investigate in terms of searching for signs of microbial activity on Earth and other planets.

Sugawara, H.; Sakakibara, M.; Ikehara, M.

2014-05-01

174

The transition between the two major Permian tectono-stratigraphic cycles in the central Southern Alps: results from facies analysis and U/Pb geochronology  

Science.gov (United States)

The Val Daone Conglomerate (VDC) is a continental clastic unit that crops out eastwards of the central Southern Alps, from the NE sector of the Collio Basin to the W as far as the Tione Basin to the E. This significant but as yet relatively unknown formation lies just above the regional unconformity that marks the boundary between the two Permian major tectono-sedimentary cycles (TSU1 and TSU2) and grades upwards paraconformably (?) to the fluvial red beds of Verrucano Lombardo/Val Gardena Sandstone, generally associated with Late Permian times. Recent palynological investigations on the VDC suggested a Guadalupian age (late Roadian-early Wordian), owing to the remarkable presence of diversified pollen associations; therefore, this sedimentary unit is to date the first one ascribed, on a palaeontological basis, to the Middle Permian in the entire Southern Alps domain. A detailed facies analysis of VDC shows deposition in amalgamated alluvial fan-braided and fluvial environments with wide channels and longitudinal bars. In its type area and Val Rendena, the VDC rests unconformably above the last volcanic episode of the TSU1. LA ICP-MS U-Pb dating on zircon from two samples of such topmost Lower Permian volcanic rocks, known as Ponte Murandin dacitic lava and Malga Plan rhyodacitic Ignimbrites (Tione Basin), provided Concordia ages of 278 ± 2 Ma (MSWD = 0.01) and 279 ± 2 Ma (MSWD = 0.16), respectively. As well as allowing us to better define the duration of the time gap between the two Permian megacycles in the central Southern Alps in almost 10 Ma, these radiometric age determinations are also significant because they enable us to regionally link the coeval volcanic bodies which crop out in the Collio Basin to the SW and in the "Athesian Volcanic Group" to the NE, respectively.

Gretter, Nicola; Ronchi, Ausonio; Langone, Antonio; Perotti, Cesare R.

2013-07-01

175

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

176

Ocean anoxia did not cause the Latest Permian Extinction  

Science.gov (United States)

The Latest Permian Extinction (LPE, ~252 million years ago) was a turning point in the history of life on Earth with a loss of ~96% of all marine species and ~70% of all terrestrial species. While, the event undoubtedly shaped the evolution of life its cause remains enigmatic. A leading hypothesis is that the global oceans became depleted in oxygen (anoxia). In order to test this hypothesis we investigated a proxy for marine oxygen levels (molybdenum isotopic composition) in shale across the LPE horizon located on the subtropical northwest margin of Pangea at that time. We studied two sedimentary records in the Sverdrup basin, Canadian High Arctic: Buchanan Lake (eastern Axel Heiberg Island; 79° 26.1'N, 87° 12.6'W), representing a distal deep-water slope environment, and West Blind Fiord (southwest Ellesmere Island; 78° 23.9'N, 85° 57.2'W), representing a deep outer shelf environment (below storm wave base). The molybdenum isotopic composition (?98/95Mo) of sediments has recently become a powerful tool as a paleo-oceanographic proxy of marine oxygen levels. Sample preparation was carried out in a metal-free clean room facility in the isotope laboratory of the Department of Physics and Astronomy, University of Calgary, Canada, that is supplied by HEPA-filtered air. Molybdenum isotope ratios were determined on a Thermo Scientific multi-collector inductively coupled plasma mass spectrometer (MC-ICP-MS) with an uncertainty better than ±0.10o for ?98/95Mo values. Results from the Buchanan Lake section show a large shift in ?98/95Mo values from 2.02o to +2.23o at the extinction horizon, consistent with onset of euxinic conditions. In contrast, West Blind Fiord shales, representing the sub-storm wave base shelf environment, show little change in the molybdenum isotopic composition (1.34o to +0.05), indicating ongoing oxic conditions across the LPE (Proemse et al., 2013). Our results suggest that areas of the Pangea continental shelf (North West Pangea) experienced oxic conditions throughout the LPE event, while anoxic conditions developed in the deep ocean. Hence, anoxic marine waters did not extend globally onto shelf environments and as such ocean anoxia cannot have been the main driver of the extinction event. While global systems were stressed by anoxia, the anoxic conditions may better represent a symptom of Siberian Trap eruptions that had catastrophic impact on the environment, potentially through nutrient loading and deposition of toxic substances into marine and terrestrial systems. Proemse et al., 2013: Molybdenum isotopic evidence for oxic marine conditions during the latest Permian extinction. Geology 41, 967-970.

Proemse, Bernadette C.; Grasby, Stephen E.; Wieser, Michael E.; Mayer, Bernhard; Beauchamp, Benoit

2014-05-01

177

An integrated study of the NE German Basin  

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The NEGermanBasin is part of the Southern Permian Basin south of the TransEuropean Suture Zone (TESZ). Here we report an attempt to integrate a variety of geological and geophysical data in order to reveal the present day deep crustal structure of the NEGermanBasin. Special focus is taken on detailed geological information, available reflection seismic data, wide angle refraction seismic data and gravity data. Based on this integrative approach, a concise crustal model is developed which ...

 bayer, U.;  scheck, M.;  rabbel, W.;  krawczyk, C. M.; -j  go?tze, H.;  stiller, M.; Th. Beileckeb; -m  marotta, A.;  barrio-alvers, L.;  kuder, J.

1999-01-01

178

Petroleum in the Junggar basin, northwestern China  

Science.gov (United States)

The Junggar basin occupies a large triangular area of some 130 000 km 2 in northwestern China. Situated between the Altay Shan (Altay Range) on the northeast and the Tian Shan (Tian Range) on the southwest, and between lesser ranges around the remainder of its periphery, the Junggar basin is completely intermontane. Its history as a basin began in the Permian, and continued as various uplifts and downwarps evolved. Through the Paleozoic the characteristics of the Junggar basin area were largely geosynclinal and marine. Its post-Permian development took place exclusively in continental regimes. Inhabitants of the Junggar basin have known and utilized its numerous oil and asphalt seeps and its spectacular spreads of asphalt for more than 2000 years, especially in the Karamay-Urho thrust belt near the northwestern rim. The first discovery of oil in the modern sense came at Dushanzi, one of the steeply folded anticlines of theÜrümqi foredeep near the southern rim. The first shallow oil in the Karamay-Urho thrust belt came in 1937, followed by commercial production in the Karamay field in 1955. Output continued to be modest until wells were drilled through local thrusts and reverse faults in the early 1980s. By 1985, cumulative production of the Karamay group of fields had reached 42,000,000 t (metric tonnes) (306,000,000 bbl), with a calculated minimum ultimate recovery of 280,000,000 t (2 billion bbl). Principal production comes from Permian and Triassic strata in continental facies. Apart from marine Mid and Upper Carboniferous strata, source rocks occur mainly in fine-grained lacustrine detrital beds of the Permian, the Triassic, the Jurassic and the Tertiary. Several uplifts and downwarps elsewhere in the Junggar basin remain to be drilled comprehensively. Results from such drilling may enhance the very important position that the Junggar already has attained in the hierarchy of China's onshore basins.

Taner, Irfan; Kamen-Kaye, Maurice; Meyerhoff, Arthur A.

179

Deep crustal structure of the Northeast German basin: New DEKORP-BASIN '96 deep-profiling results  

Digital Repository Infrastructure Vision for European Research (DRIVER)

An integrated reflection and refraction seismic survey across the Permian-Cenozoic Northeast German basin yields new insights on the evolution of intracontinental basins. No precursor rift basin was observed, but there is evidence of lower-crustal thinning and an initial magmatic stage. Minor Triassic rifting and Late Cretaceous compressional tectonics indicate that intraplate deformation was strongly influenced by older structures. Intraplate thinning and contraction were strongly decoupled ...

Dekorp-basinresearch Group,  .

1999-01-01

180

Summary of the stratigraphy, sedimentology, and mineralogy of Pennsylvanian and permian rocks of Oklahoma in relation to uranium-resource potential  

International Nuclear Information System (INIS)

Pennsylvanian-Permian strata in Oklahoma were deposited in environments which ranged from deep marine to alluvial fan. The former was most common in the Ouachita geosyncline during Early Pennsylvanian, but parts of the Anadarko basin were also relatively deep water during Middle and Late Pennsylvanian. Alluvial-fan deposits in Oklahoma are related primarily to the Amarillo-Wichita-Criner, Arbuckle, and Ouachita uplifts. As a result of erosion of the Wichita and Arbuckle areas during the Pennsylvanian-Permian, Precambrian and Cambrian felsic igneous rocks were exposed and became sources of significant quantities of feldspar in the sandstones and conglomerates, especially those on the flanks of the uplifts, and possibly sources of significant uranium concentrations in basinal waters. The Ouachita uplift, Sierra Grande-Apishapa uplift to the northwest, and possibly the Appalachian system also furnished feldspar to form the rather common subarkoses in the Upper Pennsylvanian-Permian. Feldspar is an apparent source of uranium which is present in the alluvial-fan deposits associated with the Wichita and Arbuckle uplifts, the Permian sandstones on oil-producing structures in southern Oklahoma, the lenticular sandstones on the Muenster-Waurika arch, and the tidal-flat sandstone-siltstones in western Oklahoma and possibly in north-central Oklahoma. Radioactive anomalies associated with Cherokee sandstones may be related to the Desmoinesian phosphatic shales, local depositional environments of deltaic complexes which influenced diagenetic conditions, and/or the pre-Pennsylvanian unconformity with respect to the radioactive Woodford Shale

1976-01-01

 
 
 
 
181

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

182

Diagenesis and porosity development associated with major sea level fluctuations, Upper Permian, Jameson land, east Greenland  

Energy Technology Data Exchange (ETDEWEB)

The Upper Permian of Jameson Land includes two major carbonate sequences, represented by the Karstryggen and Wegener Halvoe formations. The initial Karstryggen transgression led to the development of a shallow marine platform with structurally controlled evaporite basins (salinas) separated by stromatolitic, peloidal, or micritic carbonate depositional areas. The Wegener Havloe sequence reflects more rapid and extensive transgression with the deposition of three subcycles of fully marine, platform, or biohermal carbonates containing minor evaporites near the basin margins. Bioherms (bryozoan-brachiopod-marine cement mounds) show > 100 m of relief, indicating that large relative sea level changes were involved. Both the Karstryggen and Wgener Havloe cycles were terminated by major regressions, which led to karstic and/or fluvial incision of the underlying sequences. Not surprisingly, carbonate and evaporite diagenesis was greatly affected by these regional or eustatic sea level fluctuations. Evaporites dissolved or were replaced by calcite and celestite under the influence of meteoric waters. Limestones show collapse brecciation, grain leaching, soil development, and characteristic vadose and phreatic cements. Most significantly meteoric flushing led to massive dissolution of botryoidal marine cements (aragonite and probable high-Mg calcite) within biohermal facies on the Wegener Peninsula. This early porosity resurrection led to the preservation of porous bioherm core zones until hydrocarbon migration. Only late (posthydrocarbon), probably hydrothermal fluid flow led to cementation of the bioherm cores while expelling most of the reservoired hydrocarbons. If the sea level changes affecting the Greenlandic Permian are eustatic, then this study may provide significant clues to porosity development throughout the largely unexplored northern Zechstein basin.

Scholle, P.A.; Ulmer, D.S. (Southern Methodist Univ., Dallas, TX (USA)); Stemmerik, L. (Greenland Geological Survey, Copenhagen (Denmark))

1990-05-01

183

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

184

Comparative Earth History and Late Permian Mass Extinction  

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The repeated association during the late Neoproterozoic Era of large carbon-isotopic excursions, continental glaciation, and stratigraphically anomalous carbonate precipitation provides a framework for interpreting the reprise of these conditions on the Late Permian Earth. A paleoceanographic model that was developed to explain these stratigraphically linked phenomena suggests that the overturn of anoxic deep oceans during the Late Permian introduced high concentrations of carbon dioxide into...

Knoll, Andrew; Canfield, Donald E.; Grotzinger, John P.; Bambach, Richard

1996-01-01

185

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

Scientific Electronic Library Online (English)

Full Text Available SciELO South Africa | Language: English 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 Tapinocep [...] halus Assemblage Zone (Abrahamskraal Formation) have not been successful, largely because the exact stratigraphic ranges of fossil taxa are unknown. This gap in knowledge has limited 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.

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

186

South Pacific Sedimentary Basins  

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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

187

Microfloristic and petrographic study of coal from Faxinal mine, Rio Bonito formation from the Permian period, RS  

Energy Technology Data Exchange (ETDEWEB)

This paper is the result of the petrological and microfloristic analysis of coal seams from the Faxinal Mine (Rio Bonito Formation, Lower Permian, Parana Basin, southern Brazil). Petrological data showed a great predominance of the Vitrinite maceral group (mainly Vitrite) and a low amount of the Exinite and Inertinite groups. Dispersed wood and cuticular fragments were predominant in the palynological samples, while pollens and spores were less abundant and in general poorly preserved. Microfloristic analysis has revealed an association with a predominance of spores related to a pteridophytic plant community. The available petrological and palynological data suggest that the coal seams originated mainly in a telmatic environment. 8 references.

Guerra-Sommer, M.; Marques-Toigo, M.; Paim, P.S.G.

1984-01-01

188

Synthrusting deposition of the Pennsylvanian and Permian Strathearn Formation, Northern Carlin Trend, Nevada  

Science.gov (United States)

The middle Upper Pennsylvanian and middle Lower Permian Strathearn Formation belongs to the overlap assemblage of the Antler orogen in Nevada. At Beaver Peak, near the Carlin Trend of gold deposits, it contains synorogenic conglomerate deposits associated with emplacement of a regionally extensive, 1-km-thick tectonic wedge that is floored by the Coyote thrust. Normal marine conodont biofacies throughout the Strathearn Formation suggest middle shelf or deeper, depositional environments. The allochthon floored by the Coyote thrust has been thrust above a middle Upper Pennsylvanian, lower conglomerate unit of the Strathearn Formation. A middle Lower Permian upper conglomerate unit, the highest unit recognized in the Strathearn Formation, as well as similarly aged dolomitic siltstone, onlap directly onto Ordovician quartzarenite of the Vinini Formation that makes up most of the Coyote allochthon. Quartz grains and quartzarenite fragments of variable roundness and shape in the conglomerate units were derived from the presently adjoining tectonic lobe of mostly quartzarenite that advanced southeast (present geographic coordinates) during the late Paleozoic into the developing Strathearn basin. Chert fragments in the conglomerates probably were derived mostly from Devonian Slaven Chert, including a widespread thick me??lange unit of the Slaven Chert in the footwall of the Coyote thrust.Lithologic and shape ratio data from approximately 4200 clasts at 17 sites of the two major conglomerate units in the Strathearn Formation at Beaver Peak are roughly similar in that they contain only chert and quartzarenite clasts, and chert clasts predominate in both units. They differ in the relative proportion of the two lithologies whereby quartzarenite clasts increase sixfold in the upper unit (middle Lower Permian) versus its content in the lower conglomerate unit. Relations at the unconformity between the upper conglomerate unit and its underlying quartzarenite shows quartzarenite fragments actually breaking away from an immediately subjacent source. Ordovocian quartzarenite, which forms a tectonically uplifted wedge with the Coyote thrust at its base, became a source region for much of the quartzarenite detritus deposited preferentially in the upper parts of the Strathearn Formation. The conglomerate units of the Strathearn Formation temporally bracket emplacement of the Coyote thrust. Thrusting related to contractional reactivation of the Robert Mountains thrust system largely was completed by middle Early Permian. ?? 2004 Published by Elsevier B.V.

Theodore, T. G.; Berger, V. I.; Singer, D. A.; Harris, A. G.; Stevens, C. H.

2004-01-01

189

Illitization of Smectite in Sandstones - The Permian Unayzah Reservoir, Saudi Arabia  

Science.gov (United States)

The transformation of smectite to illite through an illite-smectite (I-S) mixed-layer is a major clay mineral reaction that occurs in a range of diagenetic environments and is commonly observed in siliciclastic sedimentary basins worldwide. This reaction is controlled by several chemical and physical factors, the two most important of which are temperature and potassium availability within the sediments. Diagenetic illite is a major factor affecting reservoir quality in all pre-Khuff clastic reservoirs in Saudi Arabia. Illite coating in the Permian Unayzah reservoir has two main morphologies: the platelet-like and fibrous illite. The former morphology is interpreted to form by transformation of infiltrated smectite during burial. This work shows that understanding the type and distribution of early diagenesis in clastic sequences is of paramount importance for the prediction of deep burial alterations and their related reservoir properties.

Abu-Khamsin, Sidqi; Al-Ramadan, Khalid

2014-05-01

190

Evidence of rifting in the northern Sydney Basin. The Maitland-Cessnock-Greta Coalfield and Cranky Corner Basin  

Energy Technology Data Exchange (ETDEWEB)

The geology of the Maitland-Cessnock-Greta Coalfield and Cranky Corner Basin contains early Permian Greta Coal Measure sedimentation and is classified as part of the Newcastle Coalfield. Two fluvial to marine sequences were recognised, and there was evidence of an uplift of a proto-oceanic rift flank in the Tamworth Belt. 4 figs.

Heeswijck, A. van [University of Newcastle, Callaghan, NSW (Australia)

1999-07-01

191

Gas hydrate contribution to Late Permian global warming  

Science.gov (United States)

Rapid gas hydrate release (the “clathrate gun” hypothesis) has been invoked as a cause for the rapid global warming and associated negative carbon isotope excursion observed during the Latest Permian Extinction (LPE). We modeled the stability of gas hydrates through a warming Middle to Late Permian world, considering three settings for methane reservoirs: 1) terrestrial hydrates, 2) hydrates on exposed continental shelves during glacial sea level drop, and 3) hydrates in deep marine settings. Model results show that terrestrial hydrates would rapidly destabilize over ?400 ky after deglaciation for moderate heatflow (40 mW/m2), and more rapidly for higher heat flow values. Exposed continental shelves would lose hydrates even more rapidly, after being flooded due to loss of ice storage on land. These two major hydrate reservoirs would thus have destabilized during the Middle to Late Permian climate warming, well prior to the LPE event. However, they may have contributed to the >2‰ negative C-isotopic shift during the late Middle Permian. Deep marine hydrates would have remained stable until LPE time. Rapid warming of deep marine waters during this time could have triggered destabilization of this reservoir, however given the configuration of one super continent, Pangea, hydrate bearing continental slopes would have been less extensive than modern day. This suggests that any potential gas hydrate release would have had only a minor contributing impact to the runaway greenhouse during the Latest Permian extinction.

Majorowicz, J.; Grasby, S. E.; Safanda, J.; Beauchamp, B.

2014-05-01

192

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

193

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)

2007-10-10

194

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

2012-01-01

195

Preliminary Study of Favorability for Uranium of the Sangre de Cristo Formation in the Las Vegas Basin, Northeastern New Mexico.  

Science.gov (United States)

Uranium favorability of the Sangre de Cristo Formation (Pennsylvanian-Permian) in the Las Vegas basin has been evaluated. The Las Vegas basin project area, located in Colfax, Mora, and San Miguel Counties, New Mexico, comprises about 3,489 sq mi. The form...

R. T. May J. R. Strand B. E. Reid W. R. Phillips

1977-01-01

196

Spectral gamma-ray signature of fluvial deposits: a case study from the Late Permian Rio do Rasto Formation, Parana Basin, Brazil; Assinatura gamaespectrometrica de depositos fluviais: estudo de caso na Formacao do Rio do Rasto, Permiano Superior da Bacia do Parana  

Energy Technology Data Exchange (ETDEWEB)

Fluvial channel-fill deposits form highly heterogeneous hydrocarbon reservoirs. The study of outcrop analogs can help in the characterization of these heterogeneities, which are usually not detected by subsurface geophysical methods. The aim of this research is to compare outcrop log signatures with grain size trends and depositional elements of the fluvial deposits of the Late Permian Rio do Rasto Formation. A series of vertical gamma-ray logs were assembled in two outcrops in order to: 1) characterize log-facies in a succession composed of alternated flood plain, channel fill and eolian strata; 2) define within-channel spectral gamma-ray variability of a mixed-load composite point bar deposit and its relationship with grain size trends and lithofacies; 3) correlate log signatures observed in the outcrop sections with deep exploratory wells drilled several tens of kilometers from the study area. The results of this study show that gamma-ray logs have good correlation with grain size trends and that different depositional elements have distinct signatures. On the other hand, point bar deposits exhibit strong lateral changes in log signature due variations in grain size and mud content within lateral accretion strata. Although frequent, the classic bell-shaped log motif was not always detected, which means that the amount of fluvial channel-fill deposits recognized in subsurface can be underestimated. Similar log signatures were detected in the boreholes, at least in the closest ones, helping in paleoenvironmental interpretation in the subsurface. (author)

Sowek, Guilherme Arruda, E-mail: arruda@ufpr.br [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil). Programa de Pos-graduacao em Geologia; Ferreira, Francisco Jose Fonseca; Vesely, Fernando Farias, E-mail: francisco.ferreira@ufpr.br, E-mail: vesely@ufpr.br [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil). Dept. de Geologia. Setor de Ciencias da Terra; Berton, Fabio, E-mail: fabioberton1@yahoo.com.br [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil)

2013-09-15

197

Upper Permian (Late Changhsingian) marine strata in Nan Province, northern Thailand  

Science.gov (United States)

In the Upper Permian of northeastern Thailand (Loei Province), continental plants have been found and to the north in Laos near Luang Prabang, continental vertebrates (Dicynodon species) have been discovered. The Middle Permian is in sharp contrast to this as it is represented only by marine sediments. West of these areas in the province of Nan in Thailand, the Upper Permian is represented by marine sediments which extend to a high level in the Upper Permian and continental beds appear to be entirely absent, at least at Pha Dang Khwai, a locality where limestone extends from the end of the Lower Permian to the Triassic.

Fontaine, Henri; Hoang, Thi Than; Kavinate, Sathaporn; Suteethorn, Varavudh; Vachard, Daniel

2013-10-01

198

Chronological constraints on the Permian geodynamic evolution of eastern Australia  

Science.gov (United States)

The New England Orogen in eastern Australia developed as a subduction-related orogen in the Late Devonian to Carboniferous, and was modified in the Permian by deformation, magmatism and oroclinal bending. The geodynamics associated with the development of the New England oroclines and the exact timing of major tectonic events is still enigmatic. Here we present new 40Ar/39Ar results from metasedimentary and volcanic rocks from the southern New England Orogen. Eight grains from four metasedimentary samples (Texas beds) that originated in the Late Devonian to Carboniferous accretionary wedge yielded reproducible plateau ages of ~ 293, ~ 280, ~ 270 and ~ 260 Ma. These results suggest a complex thermal history associated with multiple thermal events, possibly due to the proximity to Permian intrusions. Two samples from mafic volcanic rocks in the southernmost New England Orogen (Alum Mountain Volcanics and Werrie Basalt) yielded eruption ages of 271.8 ± 1.8 and 266.4 ± 3.0 Ma. The origin of these rocks was previously attributed to slab breakoff, following a period of widespread extension in the early Permian. We suggest that this phase of volcanism marked the transition from backarc extension assisted by trench retreat to overriding-plate contraction. The main phase of oroclinal bending has likely occurred during backarc extension in the early Permian, and terminated at 271–266 Ma with the processes of slab segmentation and breakoff.

Li, Pengfei; Rosenbaum, Gideon; Vasconcelos, Paulo

2014-03-01

199

Gondwana basins and their coal resources in Bangladesh  

International Nuclear Information System (INIS)

Fault bounded five Gondwana basins have been discovered in the north western Bangladesh. Among these basins show considerable amount of coal deposits. The Gondwana rocks are highly formed during the Permo-carboniferous diastrophism and later on acquired dynamic characters. In almost all basins, the Permian rocks overlie the Precambrian basement and underlie either the Tertiary or the Cretaceous sediments, structural, stratigraphic, and depositional history of these basins is more or less similar. The sedimentary sequences are composed of light to dark gray, fine to very coarse grained, sub angular to sub rounded felspathic sandstone, dark grey carbonaceous shale and sandstone, variegated conglomerate and thick coal seams (single seam max. 42.38m). The rocks are often alternated and bear the characteristics of cyclic sedimentation. The depositional environments varied from restricted drainage to open fluvial dominated low to moderate sinuous drainage system. The coal bearing basins were flanked by vegetated and swampy over bank. Age of these coals is suggested to be the late permian. Proved and probable reserves of coal in Jamalganj-Paharpur basin are 670 and 1,460 million metric tons, in Barapukuria basin 303 and 3899 million metric tons; in Barapukuria basin 303 and 389 million metric tons; and in Khalaspir basin 143 and 685 million metric tons respectively. The coal is high volatile, low sulphur, bituminous type. It can be used for different forms of thermal conversion. (author)

1994-01-01

200

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

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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. 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

2004-03-01

 
 
 
 
201

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese 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 descr [...] ição 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. Abstract in english 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.

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

202

Facies analysis of Lower Permian cyclic carbonates, west-central Ellesmere Island, Canadian Arctic  

Energy Technology Data Exchange (ETDEWEB)

At least 36 decametre-scale, largely symmetric high frequency cycles spanning ca 15 My make up the carbonate-dominated succession of Lower Permian sequence 3 of the Sverdrup Basin in Fosheim and Hamilton peninsulas. These cycles record a rift pulse characterized by the uplift, passive subsidence, collapse and passive subsidence of the Fosheim-Hamilton subbasin and show that during the rifting phase of the Severdrup Basin deposition of unconformity-bounded sequences was tectonically rather than eustatically controlled. Petrographic analysis of the carbonate-dominated facies in sequence 3 has delimited nineteen platformal facies representing lagoonal, barrier and shoals, reefal and non-reefal mid-shelf depositional environments. The high frequency depositional cycles were grouped into five idealized cycles. From proximal to distal, these include: sandstone-grainstone; grainstone-paleoaplysinid; packstone-phylloid; wackestone; and anhydrite cycles. These are grouped into pre-, syn- and post-evaporite cyclic assemblages, each of which possess a unique stacking pattern. These assemblages are associated with initial uplift-passive subsidence, collapse, and passive thermal subsidence of the Fosheim-Hamilton subbasin, respectively. 65 refs., 37 figs.

Morin, J.

1992-01-01

203

Paleotectonic reconstruction of the central Tethys domain since the Late Permian: the DARIUS Maps  

Science.gov (United States)

The DARIUS Programme is a 4-years consortium sponsored by Major Oil Companies and Research Organizations. DARIUS drive together a group of academic scientific teams whose expertise includes several domains of tectonics (structural analysis, paleotectonic reconstructions, basin analysis, subsidence modeling), stratigraphy (paleontology, sequence stratigraphy, organic matter analysis), modeling, kinematics, and geophysics. The main objective is characterizing the tecto-stratigraphic evolution of a vast domain around Central Tethys extending from Black-Sea Anatolia in the west to western Central Asia in the east. One of the final products of the DARIUS Programme is a set of 20 paleotectonic maps of the DARIUS domain ranging in age from the Late Permian to Pliocene. In these maps we propose paleotectonic reconstructions of the south-central Eurasian and north African-Arabian plates starting after the Late Paleozoic Hercynian orogeny. These palinspastic maps are based on an up-to-date kinematics reconstruction of the African, Indian and Arabian plates with respect to Eurasia. For each map we depict the major tectonic-geodynamic features (i.e. the rifts, different types of basins, major orogens and fold belts, main transcurrent faults, subduction zones, accretionary prisms...) as well as the main paleofacies. Our reconstructions are based on an accurate timing of the tectonic events that have succeeded in the central Tethyan margins since the Late Paleozoic. These events include both the main orogenies resulting from collisions of major plates and blocks and the series of openings and inversions of basins that developed in the northern and southern Tethyan margins between the main collisions. Following the Variscian orogeny that ended in the Early Permian, the Mid to Late Triassic Eo- and Mid-Cimmerian orogenies are related to the collision of Gondwanian blocs with the Pangea margin after closure of the Paleo-Tethys oceanic domain. Then, for the rest of the Mesozoic and Early Cenozoic mainly developed: (1) a northward subduction of the Neo-Tethys oceanic lithosphere beneath the southern Eurasian margin, and (2) a passive margin bordering the African-Arabian plate to the North. In this latter plate, riftings and basins developed until Late Cretaceous when the Neo-tethys ophiolites were obducted onto the Arabian passive margin. On the contrary, the North Tethys active margin recorded a complex tectonic evolution characterized by: (1) the opening of back-arc and marginal basins during the Triassic to Early-Mid Cretaceous times (e.g. Black Sea, Great Caucasus, South Caspian, Central Iran, Amu-Darya and Tadjik basins), and (2) regional compressions associated with the inversions and/or closure of these basins. The main inversions are Mid-Jurassic, Early Cretaceous, and uppermost Cretaceous-Paleogene in age. The first collision between major plates began in the Early Eocene when the northern Indian and southern Eurasian margins collided. The second one is the Arabia-Eurasia collision, which initiated in the Late Eocene. Both developed until Present, originating the Himalaya and Tien-Shan ranges and the Alpine chains respectively. After the complete closure of the remnant Tethyan oceanic domain, at the beginning of Neogene, the continent-continent collisions were developing all along the southern Eurasian active margin.

Barrier, Eric; Vrielynck, Bruno; Brunet, Marie-Françoise; Robertson, Alastair; Sosson, Marc; Zanchi, Andrea; Brouillet, Jean-françois; Kaveh, Frédéric

2014-05-01

204

The petroleum geology of the sub-Andean Maranon-Ucayali Basin, onshore Peru  

Energy Technology Data Exchange (ETDEWEB)

The Maranon-Ucayali Basin complex covers seventy five million acres east of the Andes. It trends north to south from the Ecuadorian Border where it is synonymous with the Oriente Basin to within 200 kilometers of the Bolivian border. The stratigraphy of the basin ranges from Ordovician to recent, covering remnants of larger Lower and Upper Paleozoic and Mesozoic basins. The basin is currently the foreland trough of the overthrusting Eastern Cordillera and, in common with many other sub-Andean Basins, is a Miocene to Recent feature. Three main compressional structural events are usually visible on seismic data, a Hercynian (Carboniferous-Permian) episode in the Ucayali Basin or Triassic event in the Maranon Basin, followed by Lowermost Cretaceous uplift and erosion and strong Miocene (Quachua) compressional folding. Oil prone source rocks are recognized mainly in the Devonian, Permian, and Cretaceous, but with significant potential in the Triassic and Jurassic. Four main families of oils have been identified of which three correlate with Cretaceous and Permian source rocks and one with neither. Approximately one billion barrels of oil and five trillion cubic feet of wet gas have been discovered to date, almost exclusively reservoired in Cretaceous deltaic to shallow marine clastics. A variety of trap types have been identified for which examples will be presented. These range from basement involved and detached thrust faulted anticlines to inversion and combination drape/compression anticlines.

Mathalone, J.M.P. (Eurocan USA Inc., Houston, TX (United States)); Montoya, M. (Petroperu, Lima (Peru))

1993-02-01

205

Depositional evolution of permo-triassic karoo basins in Tanzania with reference to their economic potential  

Science.gov (United States)

The Karoo basins of Tanzania contain in excess of 3000 m of sediments which were preserved in several NNE-NE striking half grabens or other structural basin conditions. They are all intracratonic basins, most of which filled with terrestrial sediments. In some basins situated nearer the coastal region short marine incursions occurred in the Late Permian. The Ruhuhu Rasin in SW Tanzania provides a typical depositional sequence of a Karoo basin in eastern Africa. Sedimentation commenced with glacigene deposits. These are of Late Carboniferous to Early Permian age and may be equated with other glacial successions in Africa and elsewhere in Gondwana. The glacigene beds are overlain by fluvial-deltaic coal-bearing deposits succeeded by arkoses and continental red beds. A transitionary formation of carbonaceous shales with impure coals gradually develops into thick lacustrine series which are topped by Late Permian bone bearing beds. The Triassic is characterized by a very thick fluvio-deltaic succession of siliciclastics resting with regional unconformity on the Permian. This Early Triassic sequence exhibits well-developed repetitive depositional cycles. Current azimuth measurements indicate fluctuating flow regimes in the Early Permian but relative stable source areas to the west of the basin later on. The depositional evolution of the Ruhuhu Basin is controlled by both tectonic and climatic factors. During basin evolution important energy resources were deposited such as considerable reserves of coal and source rocks of moderate potential for hydrocarbon generation. Uranium enrichment is observed in the Triassic arenaceous series where diagenetic alterations and subsequent cementation processes led to the formation of laumontite. Post Karoo dykes and plugs had only local effect on thermal evolution of potential source rocks. Enrichments of elements, i.e., Nb, Zr, Rb, Cr, and V present additional exploration targets. A comparison with the Karoo basins of the coastal region indicates possible lithological correlation by the application of sequence stratigraphy. No early Permian deposits are exposed in the coastal Karoo basins but their existence within the deeper parts of these basins cannot be ruled out. There, composition of organic matter analysed so far suggests subsidence and heat exposure exceeding post maturity stage.

Kreuser, T.; Wopfner, H.; Kaaya, C. Z.; Markwort, S.; Semkiwa, P. M.; Aslandis, P.

206

The Triassic dicynodont Kombuisia (Synapsida, Anomodontia) from Antarctica, a refuge from the terrestrial Permian-Triassic mass extinction.  

Science.gov (United States)

Fossils from the central Transantarctic Mountains in Antarctica are referred to a new species of the Triassic genus Kombuisia, one of four dicynodont lineages known to survive the end-Permian mass extinction. The specimens show a unique combination of characters only present in this genus, but the new species can be distinguished from the type species of the genus, Kombuisia frerensis, by the presence of a reduced but slit-like pineal foramen and the lack of contact between the postorbitals. Although incomplete, the Antarctic specimens are significant because Kombuisia was previously known only from the South African Karoo Basin and the new specimens extend the taxon's biogeographic range to a wider portion of southern Pangaea. In addition, the new finds extend the known stratigraphic range of Kombuisia from the Middle Triassic subzone B of the Cynognathus Assemblage Zone into rocks that are equivalent in age to the Lower Triassic Lystrosaurus Assemblage Zone, shortening the proposed ghost lineage of this taxon. Most importantly, the occurrence of Kombuisia and Lystrosaurus mccaigi in the Lower Triassic of Antarctica suggests that this area served as a refuge from some of the effects of the end-Permian extinction. The composition of the lower Fremouw Formation fauna implies a community structure similar to that of the ecologically anomalous Lystrosaurus Assemblage Zone of South Africa, providing additional evidence for widespread ecological disturbance in the extinction's aftermath. PMID:19956920

Fröbisch, Jörg; Angielczyk, Kenneth D; Sidor, Christian A

2010-02-01

207

Overview of the structural geology and tectonics of the Central Basin Platform, Delaware Basin, and Midland Basin, West Texas and New Mexico  

Energy Technology Data Exchange (ETDEWEB)

The structural geology and tectonics of the Permian Basin were investigated using an integrated approach incorporating satellite imagery, aeromagnetics, gravity, seismic, regional subsurface mapping and published literature. The two primary emphases were on: (1) delineating the temporal and spatial evolution of the regional stress state; and (2) calculating the amount of regional shortening or contraction. Secondary objectives included delineation of basement and shallower fault zones, identification of structural style, characterization of fractured zones, analysis of surficial linear features on satellite imagery and their correlation to deeper structures. Gandu Unit, also known as Andector Field at the Ellenburger level and Goldsmith Field at Permian and younger reservoir horizons, is the primary area of interest and lies in the northern part of Ector county. The field trends northwest across the county line into Andrews County. The field(s) are located along an Ellenburger thrust anticline trap on the eastern margin of the Central Basin Platform.

Hoak, T. [Kestrel Geoscience, Littleton, CO (United States); Sundberg, K. [Phillips Petroleum Co., Bartlesville, OK (United States); Ortoleva, P. [Indiana Univ., Bloomington, IN (United States)

1998-12-31

208

Final closure of the Paleo-Asian Ocean along the Solonker Suture Zone: Constraints from geochronological and geochemical data of Permian volcanic and sedimentary rocks  

Science.gov (United States)

is a broad consensus that the Solonker Suture Zone marks the final closure of the Paleo-Asian Ocean, which led to the formation of the eastern segment of the Central Asian Orogenic Belt. However, when and how the final closure occurred still remains controversial. To address this issue, provenance analysis of Permian sedimentary rocks of arc basins along the Xar Moron River was carried out. Geochemical analysis revealed a close relationship between the sedimentary and volcanic rock suite in the study region suggesting short transport distances and a complex convergent arc setting. Detrital zircon U-Pb analysis identified two major age provenances: (1) the Precambrian basement of the North China Craton (~2497 Ma and ~1844 Ma) and (2) the Paleozoic Southern Accretionary Orogen along the northern margin of North China (~436 Ma and ~269 Ma). The present locations of identified age provenances indicate southward subduction beneath the northern margin of North China. A comparison of the youngest age population in the sedimentary rocks with U-Pb ages obtained for subduction-related volcanic rocks implies that the Solonker Suture Zone formed from the Late Permian to Early Triassic. The results of our study advocate a complex Permian arc system which was probably similar to present-day Southeast Asia.

Eizenhöfer, Paul R.; Zhao, Guochun; Zhang, Jian; Sun, Min

2014-04-01

209

Calcium isotope constraints on the end-Permian mass extinction  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The end-Permian mass extinction horizon is marked by an abrupt shift in style of carbonate sedimentation and a negative excursion in the carbon isotope (?13C) composition of carbonate minerals. Several extinction scenarios consistent with these observations have been put forward. Secular variation in the calcium isotope (?44/40Ca) composition of marine sediments provides a tool for distinguishing among these possibilities and thereby constraining the causes of mass extinction. Here we repor...

Payne, Jonathan L.; Turchyn, Alexandra V.; Paytan, Adina; Depaolo, Donald J.; Lehrmann, Daniel J.; Yu, Meiyi; Wei, Jiayong

2010-01-01

210

Hooked: Habits of the Chinese Permian gigantopterid Gigantonoclea  

Science.gov (United States)

Based upon anatomical evidence, Permian aged gigantopterid fossils are in general reconstructed as climbing or scrambling plants. Gigantonoclea, a genus of adpressed gigantopterid foliage from the Permian of northern China, has been reported to co-occur with hook-like organs that were interpreted as indicating a scrambling/climbing habit. We reinvestigated these hook-like structures and re-evaluated the nature of the co-occurrences in context with the flora preserved in each plant-bearing fossil 'bed' in the North China sedimentary succession. New findings show that the species Gigantonoclea hallei probably climbed using specially adapted clusters of compound grappling hook-like shoots borne on the stems. This structural arrangement comprising shoots of hooks is new to the scrambling/climbing concept in gigantopterids. However, a key figured specimen previously reported as showing intermediate hook-tipped leaf morphology on a sole pinnule tip is discounted as such and is reinterpreted as a 'normal' pinnule partially hidden under sediment that results in an unusual appearance to this pinnule tip. Adaptations for climbing or scrambling based upon 'hooked leaves' observed in Gigantonoclea lagrelii are no longer supported and are reinterpreted as incompletely expanded leaves where the vernation process was interrupted. These data weaken prior interpretations of G. lagrelii as a climber/scrambler and raise doubts about the ubiquity of hooks amongst the gigantopterids as structures enabling them to climb or scramble their way through the Permian world.

Seyfullah, Leyla J.; Glasspool, Ian J.; Hilton, Jason

2014-04-01

211

Petroleum Source Rock Potential and Thermal Maturity, Palo Duro Basin, Texas.  

Science.gov (United States)

Samples collected from 20 geographically widespread wells in the sparsely drilled Palo Duro Basin were analyzed for total organic carbon content (TOC). Highest values of TOC, up to 6.9%, occur in Upper Permian San Andres dolomite in the southern part of t...

S. P. Dutton

1980-01-01

212

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

213

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English 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 Br [...] asil. 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. 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, southe [...] rn 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.

ELISEU V., DIAS; MARIO C., BARBERENA.

214

Structural Complexities Influencing Biostratigraphic Interpretations of the Permian Nansen Formation type-section, Ellesmere Island, Canada  

Science.gov (United States)

The Carboniferous to Permian aged Nansen Formation is a cyclic carbonate shelf deposit and potential hydrocarbon reservoir. This formation is the thickest, most widespread carbonate sequence in the Sverdrup Basin. Deformed during the Eurekan Orogeny, the Nansen Fm. is topographically prominent and responsible for the rugged topography on Axel Heiburg and Ellesmere Island. The type-section for the Nansen Fm. is located on the north side of Hare Fiord, along Girty Creek. At this location there is an estimated stratigraphic thickness of 2 km. Due to easier access most of the stratigraphic work has been completed on nearby glacially exposed sections that traverse parallel to Girty Creek along glacial margins. Extensive biostratigraphy was completed on a glacier section to the west, however, in a glacier section to the east of Girty Creek, structural complexities appear to be repeating sections of the formation. Here, the Nansen formation is bounded by two regional reverse faults. This has produced duplex structures, with clearly exposed stacked horses, footwall synclines, and truncations. By projecting the structures observed along the eastern glacier section to the western glacier section that was used for biostratigraphic studies, it is clear that these structures would affect biostratigraphic interpretations. It was previously noted by biostratigraphers that thrust faults appear to be repeating sections of the Nansen formation. However by correlating all observed faults with the biostratigraphy, we can determine the extent to which the faulting has affected the interpretations, and whether all faults or stratigraphic repetitions are accounted for.

Hill, M.; Guest, B.

2011-12-01

215

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

216

Area environmental characterization report of the Dalhart and Palo Duro basins in the Texas Panhandle. Volume II. Palo Duro basin  

International Nuclear Information System (INIS)

This area report describes the environmental characteristics of the Dalhart and Palo Duro basins of the Texas Panhandle portion of the Permian basin. Both basins are rather sparsely populated, and the overall population is decreasing. The economic base is centered on agribusiness and manufacturing. Most of the potentially conflicting land uses in both basins (i.e., parks, historic sites) occupy small land areas, with the exception of a national grassland in the Dalhart and military air training routes in both basins. Ground transportation in the Dalhart basin is adequate, and it is well developed in the Palo Duro basin. In both basins irrigation constitutes the principal water use, and groundwater is the principal source. However, the dominant aquifer, the Ogallala, is being depleted. Both basins consist primarily of grasslands, rangelands, and agricultural areas. No critical terrestrial or aquatic habitats have been identified in the basins, though several endangered, threatened, or rare terrestrial species occur in or near the basins. Aquatic resources in both basins are limited because of the intermittent availability of water and the high salt content of some water bodies. Playa lakes are common, though usually seasonal or rain dependent. The climate of the area is semiarid, with low humidity, relatively high wind speeds, and high variable precipitation. Restrictive dispersion conditions are infrequent. National ambient secondary air quality standards for particulates are being exceeded in the area, largely because of fugitive dust, although there are some particulate point sources

1982-01-01

217

Permian palynostratigraphy and palaeoclimate of Lingala-Koyagudem coalbelt, Godavari Graben, Andhra Pradesh, India  

Science.gov (United States)

Godavari Graben, one of the biggest basins among several Gondwana basins of India, holds a unique position not only because of its geographical location in South India, but also due to the presence of almost complete succession from Permian to Cretaceous sediments. The Graben is traversed by many small faults due to which the dating and correlation of coal bearing horizons is difficult in this area. As palynology is one of the most reliable parameter for dating, correlation and characterization of continental deposits, palynological studies have been carried out in order to date and correlate the coal bearing horizons of Gundala, Mamakannu and Kachinapalli areas from Lingala-Koyagudem coalbelt of Godavari Graben.The distributional pattern of various palynotaxa has suggested the occurrence of eight distinct palynozones in five borecores of Gundala (MLG-23, MLG-24, and MLG-28), Mamakannu (MMK-19) and Kachinapalli (MGK-6) areas. These palynozones are comparable to Talchir, Lower Karharbari, Upper Karharbari, Barakar and Raniganj palynoflora of Indian Lower Gondwana. Palynozone-1 is equivalent to Parasaccites Assemblage of Talchir Palynoflora; Palynozone-2 is correlatable with Callumispora + Parasaccites Assemblage of Lower Karharbari palynoflora; Palynozone-3 corresponds well with Parasaccites + Scheuringipollenites Assemblage of Upper Karharbari palynoflora; Palynozone-4 is comparable to Scheuringipollenites Assemblage of Barakar palynoflora; Palynozone-5 is correlatable with Faunipollenites + Striatopodocarpites Assemblage of Raniganj palynoflora; Palynozone-6 is comparable with Striasulcites Assemblage of Raniganj palynoflora; Palynozone-7 shows its equivalence with Parasaccites Assemblage of Raniganj palynoflora and Palynozone-8 corresponds well with the Crescentipollenites Assemblage of Raniganj palynoflora. On the basis of palynofloral evidences, it has been suggested that palaeoclimate during Palynozone 1-3 was cool but humidity was more in Palynozone-3 in comparison to Palynozone-2. Warmer phase started during Palynozone-4 with thick coal deposits, while Palynozones 5-8 representing Raniganj palynoflora indicate warm climate with very high humidity.

Aggarwal, Neha; Jha, Neerja

2013-03-01

218

Repository site data and information in bedded salt: Palo Duro Basin, Texas  

International Nuclear Information System (INIS)

This report is a compilation of data from the literature on the Palo Duro Basin. The Palo Duro Basin is a structural basin, about 150 miles long and 80 miles wide, that is a part of the much larger Permian Basin. The US Department of Energy is investigating the Palo Duro Basin as a potentially suitable area for the site of a repository for the disposal of high-level radioactive waste. Sediments overlying the Precambrian basement range from about 5000 to about 11,000 ft in thickness and from Cambrian to Holocene in age. The strata in the Palo Duro Basin that are of primary interest to the Department of Energy are the bedded salts of the Permian San Andres Formation. The total thickness of the bedded salts is about 2000 ft. The geology of the Palo Duro Basin is well understood. A great deal of information exists on the properties of salt, although much of the available information was not collected in the Palo Duro Basin. Mineral resources are not currently being exploited from the center of the Palo Duro Basin at depth, although the possibility of exploration for and development of such resources can not be ruled out. The continued existence of salts of Permian age indicates a lack of any large amount of circulating ground water. The hydrology of the pre-Tertiary rocks, however, is currently too poorly understood to carry out detailed, site-specific hydrologic modeling with a high degree of confidence. In general, ground water flows from west to east in the Basin. There is little or no hydraulic connection between aquifers above and below the salt sequences. Potable water is pumped from the Ogallala aquifer. Most of the other aquifers yield only nonpotable water. More extensive hydrological data are needed for detailed future modeling in support of risk assessment for a possible repository for high-level waste in the Palo Duro Basin. 464 references

1983-01-01

219

A sudden end-Permian mass extinction (Invited)  

Science.gov (United States)

The end-Permian mass extinction is the largest of the Phanerozoic. In the immediate aftermath the marine ecosystem was dominated by microbial and communities with disaster taxa. Plausible kill mechanism includes an extremely rapid, explosive release of gases such as carbon dioxide, methane and hydrogen sulfide. Siberian flood volcanism has been suggested as the most possible mechanism to trigger the massive release of greenhouse gases from volcanic eruptions and interaction of magmas with carbon from thick organic-rich deposits or rapid venting of coal-derived methane or massive combustion of coal. A sharp ?13C isotopic excursion, rapid disappearance of carbonate benthic communities and ?18O data from conodont apatite suggest rapid global warming. The end-Permian mass extinction occurred in less than 200,000 years. This extinction interval is constrained by two ash beds (Beds 25 and 28) at the Meishan section. However, the extinction patterns remain controversial largely due to the condensed nature of the Meishan sections. Geochemical signals and their interpretations are also contentious. Thus, the level of achievable stratigraphic resolution becomes crucial to determine the nature of the event and a detailed study of the extinction interval is essential to unravel the extinction pattern, chemostratigraphy, and the causes. However, the extinction interval at Meishan is only 26 cm thick and contains distinct gaps at the Permian-Triassic boundary (PTB) and possibly the base of Bed 25. Thus, it is impossible to resolve a detailed extinction pattern. Studying expanded sections is crucial to understand the detailed events before, during and after the main extinction. In this report, we show a highly-expanded Permian-Triassic boundary section in Guangxi Province, South China. The last 4.5 m between beds 22 and 28 of the Meishan sections is represented by a sequence of ~560 m at the section and the extinction interval between beds 24e and 28 at Meishan is represented by an interval about ~95 m which contains abundant benthic fossils. This expanded section reveals a very sudden extinction in a transgressive sequence that is inferred to have occurred within a few thousands of years.

Shen, S.

2013-12-01

220

Ocean redox change at the Permian-Triassic mass extinction  

DEFF Research Database (Denmark)

Earthâ??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 Earthâ??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.

2013-01-01

 
 
 
 
221

Temporal variability in charcoal distribution in Permian coal: Implications for interpreting palaeowildfire history  

Science.gov (United States)

The presence of fossil charcoal [inertinite (Scott and Glasspool, 2007)] in coal provides evidence for palaeowildfire event/s. Charcoal distribution has been shown to vary both spatially and temporally in modern wildfires, therefore this needs to be taken into consideration when studying inertinite from palaeowildfires in order to better understand palaeowildfire history. To determine whether this variation occurs in the geological past, charcoal produced by palaeowildfires from four randomly sampled Late Permian in situ coal (fossil peat) pillars from the Kuznetsk Basin, Russia [seam 78 (a and b) and seam 88 (a and b)] have been studied using petrographic techniques. The use of in situ coal pillars are judged to be essential for this type of work as they retain the orientation of the original inertinite distribution, unlike the crushed coals that are typically used for commercial petrographic analysis. These coal pillars contain charcoal in all lithotype units, but show temporal variation both in the amount and type of inertinite between successive lithotype units. Furthermore, the pillars also contain varying amounts of charcoal both within and between seams [mean inertinite: 78(a) 29.8%, 78(b) 42.6%, 88(a) 48% and 88(b) 35%]. The distribution of this charcoal in these pillars can be used to interpret palaeowildfire type. All pillars show: (1) microscopic, scattered charcoal which is interpreted to represent background fire events and (2) macroscopic charcoal which is either scattered or contained in charcoal horizons, which is interpreted to represent surface fire events. Previous petrographic work on crushed coals by Pakh and Artser (2003) has shown that seam 78 has a higher inertinite content (33%) than seam 88 (22%), in contrast this study has shown that the pillars from seam 88 contain more inertinite (with a combined mean of 41.5%) than those from seam 78 (combined mean = 36.2%). This may suggest that during the formation of pillars 88(a,b) fires were either more frequent or that more charcoal was produced in individual fire events compared to the rest of seam 88. The variation in the amount of inertinite both within and between pillars provides evidence for temporal variation in wildfire history for the duration of both pillar and seam formation in this Late Permian peat-forming environment.

Hudspith, V. A.; Scott, A. C.; Collinson, M. E.

2012-04-01

222

The large scale structures of the Late Permian Zechstein 3 intra-salt stringer, northern Netherlands  

Science.gov (United States)

The three dimensional study of the internal structure of salt structures on the several different scales is of fundamental importance to understand mechanisms of salt tectonics, for intra-salt storage cavern stability, and for drilling in salt-prone petroleum systems with associated problems like borehole instability and overpressured fluids. While most salt-related studies depict salt as structureless bodies, detailed field-, well- and mining gallery mapping have shown an amazing spectrum of brittle, complexly folded, faulted and boudinaged intra-salt layers ("stringers"), but mostly on a very local scale. First detailed insights into these three-dimensionally heterogeneous and very complex structures of the layered evaporites were provided by observations in modern high-resolution 3D seismic data, such as across the Late Permian Zechstein in the Southern Permian Basin (SPB). In the northern Dutch onshore part of the SPB, the Z2 and Z3 halite interface is characterized by the seismically visible reflections of the 30-150 m thick Z3 anhydrite-carbonate layer that clearly resolves the complex intra-salt structure. This stringer shows a high fragmentation into blocks of several tens of meters to kilometres diameter with complexly folded and faulted structures that correlate to the regionally varying deformation stages of the Zechstein, as it is implied by the shape of Top Salt. After an extensive seismic mapping over the entire northern Netherlands, structures observed include an extensive network of thicker zones, inferred to result from early karstification. Later, this template of relatively strong zones was deformed into large scale folds and boudins as the result of salt tectonics. Non-plane-strain salt flow produced complex fold and boudin geometries that overprint each other. There are some indications of a feedback between the early internal evolution of this salt giant and the position of later salt structures. The stringer has a higher density then the surrounding halite, and in the literature there is some controversy concerning the sinking rates of single stringer fragments. We observed no structures indicative of sinking, but conclude that the present-day position of the blocks can be explained by internal folding of the entire salt section. In the end, this study aims at (i) improving the understanding of the development and dynamics of Zechstein halokinesis, (ii) gaining new insights into the 3D internal deformation in salt, and (iii) a linkage of processes in the layered evaporites with the deformation of the enclosing sub- and supra-salt sediments.

van Gent, H.; Strozyk, F.; Urai, J. L.; de Keijzer, M.; Kukla, P. A.

2012-04-01

223

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

224

Panjal Paleomagnetism: Implications for Early Permian Gondwana break-up  

Science.gov (United States)

The mid-Early Permian represents an important phase in Pangaea's development marking the time when the >13,000 km-long string of terranes that are collectively known as 'Cimmeria' separated from Gondwana's Tethyan margin (northern Africa-NE Arabia-northern India-NW and northern Australia). The ~289 Ma Panjal Traps of NW India (Kashmir) are one of a number of mafic suites (Abor, Sikkim etc.) that were erupted onto the Indian block possibly during the separation of the Lhasa/SE Qiangtang block. Herein, we report data from the first modern paleomagnetic study of the unit. Results from four quarry sections (15 individual cooling units) from a locality close to Srinagar together form a tectonically coherent sequence spanning 2-3 km of stratigraphy. The derived direction and paleopole yield key new information concerning (1) the Early Permian location of India, and by inference that of central Gondwana, and (2) inform debates related to Cimmeria's breakup from eastern Gondwana. Moreover, they provide a new independent control for assessing NW Greater India's extent prior to its collision with Asia and the amount of vertical-axis rotation this sector of the Himalayan range experienced in the mid to late Cenozoic.

Stojanovic, D.; Aitchison, J.; Ali, J. R.; Ahmad, T.; Ahmad Dar, R.; Agarwal, A.; Roeder, T.

2013-12-01

225

Geochemistry of oils from the Junggar basin, northwest China  

Energy Technology Data Exchange (ETDEWEB)

The Junggar basin of northwestern China is a structural basin containing a thick sequence of Paleozoic-Pleistocene rocks with estimated oil reserves of as much as 5 billion bbl. Analyses of 19 oil samples from nine producing fields and two oil-stained cores in the Junggar basin revealed the presence of at least five genetic oil types. The geo-chemistry of the oils indicates source organic matter deposited in fresh to brackish lake and marine environments, including coaly organic matter sources. The volumetrically most important oil type discovered to date is produced from Late Carboniferous-Middle Triassic reservoirs in the giant Karamay field and nearby fields located along the northwestern margin of the Junggar basin. Oil produced from the Mahu field, located downdip in a depression east of the Karamay field, is from a different source than Karamay oils. Unique oil types are also produced from an upper Permian reservoir at Jimusar field in the southeastern part of the basin, and from Tertiary (Oligocene) rocks at Dushanzi field and Lower Jurassic rocks at Qigu field, both located along the southern margin of the basin. Previous studies have demonstrated the presence of Upper Permian source rocks, and the possibility of Mesozoic or Tertiary sources has been proposed, but not tested by geochemical analysis, although analyses of some possible Jurassic coal source rocks have been reported. Our findings indicate that several effective source rocks are present in the basin, including local sources of Mesozoic or younger age for oil accumulations along the southern and southeastern margins of the basin. Future exploration or assessment of petroleum potential of the basin can be improved by considering the geological relationships among oil types, possible oil source rocks, and reservoirs.

Clayton, J.L.; King, J.D.; Lillis, P.G. [Geological Survey, Denver, CO (United States)] [and others

1997-11-01

226

Autochthonous deposition of Indian coal beds with palaeobotanical evidences of in situ plants from Saharjuri Basin, Jharkhand  

Energy Technology Data Exchange (ETDEWEB)

In situ Glossopteris plants on Vertebraria root, in situ Glossopteris seedlings, i.e. Deogharia and the first report of Annularia leafy shoots emerging from upright axes are recorded from the coal-bearing Late-Early Permian (Barakar Formation) sediments of Saharjuri Basin, Lower Gondwana. Besides, root beds, upright Vertebraria root, and Diphyllopteris seedlings are recorded from other Lower Gondwana coal fields. All evidences are considered to suggest autochthonous origin of the respective coal beds of the Indian Lower Gondwana basins.

Banerjee, M. [University of Calcutta, Calcutta (India). Dept. of Botany

2005-05-10

227

XIV international congress on the Carboniferous and Permian (ICCP): programme with abstracts  

Energy Technology Data Exchange (ETDEWEB)

The document contains approximately 300 abstracts of papers presented at 33 technical sessions and three poster sessions. The sessions are Carboniferous stratigraphy (2 sessions), Upper Paleozoic reefs, Carboniferous coal (2 sessions), Lower to Middle Permian chronostratigraphy: Permian subcommission (2 sessions), micropaleontology (2 sessions), core conference, Upper Paleozoic palynology, stratigraphy, tectonics and chemostratigraphy (2 sessions), cyclotherms (2 sessions), western Canada geology, petroleum geology, Upper Paleozoic macroflora (2 sessions), Carboniferous boundaries SCCS, Pander Society - non C/P conodonts (3 sessions), Permian-Triassic boundary, Canadian Paleontology Conference (CPC 9) (3 sessions), Upper Paleozoic stratigraphy and paleogeography (2 sessions), and paleoecology, biostratigraphy and macropaleoontology (2 sessions). Twenty-five are abstracted separately.

Hills, L.; Bamber, W. [eds.

1999-07-01

228

The Permian volcanism of Sardinia revisited: new geochronological and geochemical data as a key for geodynamic evolution of the western Peri-Tethian sector  

Science.gov (United States)

Recent studies have confirmed the important role played by magmatism affecting Sardinian basins during the latest Carboniferous and Permian age (Cortesogno et al. 1998; Buzzi et al., 2008; Casini et al., 2012). To-date, most of the geochronological analysis performed on the Permian volcanic events in the island are methodologically overcome and frequently not in tune with the stratigraphy. In the north-western and central-southeastern Sardinian basins (Nurra, Perdasdefogu, Seui-Seulo and Escalaplano), the late-post Variscan tectonic collapse favored the emplacement of a calc-alkaline products not only in the form of generally shallow intrusions but also volcanism within intramontane strike-slip basins. This magmatism is expressed both as pyroclastic rocks-lava flows filling small half-graben basins and hypabyssal intrusions (lava-domes and dykes). These volcano-sedimentary troughs generally include both external and internal igneous eruptions as well as the detrital products eroded from the surrounding structural highs. Rhyolites, andesites and dacites are the main rock types while trachydacites and trachyandesites are less represented. Our goal is to couple the petrographic and geochemical features of 17 selected samples stratigraphically constrained and new U-Pb ages data on zircons from the post-Variscan effusive rocks in Sardinia. The whole-rock and REE geochemical features confirm a progressive evolution in the post-Variscan extensional, trans-tensile regime in with and fits an origin in a stacking of nappes associated with thermal re-equilibration of lithospheric mantle and telescopic partial melting of the thickened crust. The process is dominated by AFC. As far as the geochronological analysis is concerned, a preliminary cathodoluminescence study has been performed on all mounted crystals in order to select the precise location of the shot points. Each crystal has been analyzed for U, Th and Pb in the epoxy mount by laser-ablation inductively coupled plasma mass spectrometry (LA ICP-MS) at the Institute of Geosciences and Earth Resources IGG-CNR of Pavia. The time lag of Permian ages recorded along the Sardinia cross section is significant in the modeling of the post- Variscan tectonic, sedimentary evolution and in the perspective of the geodynamic evolution of Southern Variscides. REFERENCES Casini L., Cuccuru S., Maino M., Oggiano G., Tiepolo M 2012. Emplacement of the Arzachena Pluton (Corsica-Sardinia Batholith) and the geodynamics of incoming Pangaea. Tectonophysics 544-545 (2012) 31-49. Buzzi L., Gaggero L., Oggiano G. 2008. The Santa Giusta ignimbrite (NW Sardinia): a clue for the magmatic, structural and sedimentary evolution of a Variscan segment between Early Permian and Triassic. Italian Journal of Geoscience 127(3), 683-695. Cortesogno L., Cassinis G., Dallagiovanna G., Gaggero L., Oggiano G., Ronchi A., Seno S., Vanossi M. 1998. The Variscan post-collisional volcanism in Late Carboniferous-Permian sequences of Ligurian Alps, Southern Alps and Sardinia (Italy): a synthesis. Lithos 45, 305-328.

Gaggero, Laura; Gretter, Nicola; Lago, Marceliano; Langone, Antonio; Oggiano, Giacomo; Ronchi, Ausonio

2014-05-01

229

Characterization of an upper Permian tight gas reservoir. A multidisciplinary, multiscale analysis from the rotliegend, northern Germany  

Energy Technology Data Exchange (ETDEWEB)

Outstanding Ph.D. thesis nominated for a Springer Theses Prize by the RWTH Aachen University, Germany. Uses various approaches and covers a broad range of disciplines. Integrated study, carried out on multiple scales with state of the art technical equipment, that only few laboratories can offer worldwide. ''The thesis of Philipp Antrett is focused on reservoir properties, petrography, lithofacies and sedimentology, core analysis and nanoporosity studies. It will be of major interest for colleagues involved in the exploration and production of tight gas reservoirs in Northern Europe and elsewhere.'' - Francois Roure, August 2012 This thesis describes a multidisciplinary, multiscale approach to the analysis of tight gas reservoirs. It focused initially on the facies architecture of a Permian tight gas field in the Southern Permian Basin (SPB), East Frisia, northern Germany. To improve field development, 3D seismic data, wireline and core data were compared to a reservoir analogue in the Panamint Valley, California, United States. In addition to the large scale approach, a work flow that investigates microporosity by combining Scanning Electron Microscopy-Broad Ion Beam (SEM-BIB) and optical microscopy was developed. For a better understanding of the depositional environment and reservoir rock distribution in the SPB, a sedimentary facies analysis of four cores from the tight gas field in East Frisia was compared to a second study area in northern central Germany. This study demonstrates that tight gas exploration and production requires multidisciplinary, multiscale approaches beyond standard seismic interpretation work flows to better understand the temporal and spatial evolution of these complex reservoirs.

Antrett, Philipp [RWTH Aachen Univ. (Germany). Energy and Mineral Resources Group

2013-06-01

230

A modern vs. Permian black shale - the hydrography, primary productivity, and water-column chemistry of deposition  

Science.gov (United States)

The sediment currently accumulating in the Cariaco Basin, on the continental shelf of Venezuela, has an elevated organic-carbon content of approximately 5%; is accumulating under O2-depleted bottom-water conditions (SO42- reduction); is composed dominantly of foraminiferal calcite, diatomaceous silica, clay, and silt; and is dark greenish gray in color. Upon lithification, it will become a black shale. Recent studies have established the hydrography of the basin and the level of primary productivity and bottom-water redox conditions. These properties are used to model accumulation rates of Cd, Cr, Cu, Mo, Ni, V, and Zn on the seafloor. The model rates agree closely with measured rates for the uppermost surface sediment.The model is applied to the Meade Peak Phosphatic Shale Member of the Phosphoria Formation, a phosphate deposit of Permian age in the northwest United States. It too has all of the requisite properties of a black shale. Although the deposit is a world-class phosphorite, it is composed mostly of phosphatic mudstone and siltstone, chert, limestone, and dolomite. It has organic-carbon concentrations of up to 15%, is strongly enriched in several trace elements above a terrigenous contribution and is black. The trace-element accumulation defines a mean primary productivity in the photic zone of the Phosphoria Basin as moderate, at 500 g m-2 year-1 organic carbon, comparable to primary productivity in the Cariaco Basin. The source of nutrient-enriched water that was imported into the Phosphoria Basin, upwelled into the photic zone, and supported primary productivity was an O2 minimum zone of the open ocean. The depth range over which the water was imported would have been between approximately 100 and 600 m. The mean residence time of bottom water in the basin was approximately 4 years vs. 100 years in the Cariaco Basin. The bottom water was O2 depleted, but it was denitrifying, or NO3- reducing, rather than SO42- reducing. Published by Elsevier B.V.

Piper, D. Z.; Perkins, R. B.

2004-01-01

231

Late Paleozoic geodynamic evolution of the Junggar Basin (Northwestern China) : insights from new paleomagnetic results  

Science.gov (United States)

The continental or oceanic nature and the geographic extent of the Junggar basement remain controversial; nevertheless this area presents special interests in order to better understand the Paleozoic tectonic framework of Central Asia. A paleomagnetic study has been performed on Late Paleozoic rocks around Junggar Basin in order to check if it can be regarded as a rigid block at the end of the Paleozoic. 158 sedimentary and volcano-sedimentary rock cores have been collected on 25 sites. Among them, 11 sites located in the southern border of the basin, in Bogda Shan near Urumqi, consist of Permian red sandstone, and 14 sites of Early Carboniferous grey sandstone come from the West Junggar Mountains, near Karamay. Magnetite is the main carrier for magnetic signal in this collection. In Permian red beds of Bogda Shan area, the characteristic components of P1 and P2 show a solo reversed polarity and passed a positive regional fold test, the magnetization can be therefore considered as primary. Two new paleomagnetic poles have been consequently calculated for the periods of P1 at 79.5°N, 36.6°E and of P2 at 60.4°N, 4.7°E with a paleolatitude at ~50 and 40°N, respectively. The Early Carboniferous sites are characterized by reverse polarity, and show a negative fold test indicating post-folding secondary magnetization. Thus, according to the spatial distribution of the sampling sites with respect to Late Carboniferous-Early Permian granitic plutons and Late Permian mafic dykes, two subgroups can be distinguished. The remagnetized sites, related to Late Carboniferous - Early Permian granite emplacement, yield a paleomagnetic pole at 65.3°N, 329.8°E, and the sites located at the vicinity of Late Permian mafic dykes present a paleomagnetic pole at 64.8°N, 179.4°E with relatively lower paleolatitudes at ~30 to 35°N, respectively. Our paleomagnetic data from sections near Urumqi, and previous ones as well, show stationary and coherent poles for South Junggar area during the Carboniferous and Permian. These poles are close to the Present. However, paleomagnetic data from NW Junggar indicate a significant anticlockwise rotation between the Late Carboniferous-Early Permian and the Late Permian. It seems that paleolatitudes of NW Junggar rocks are similar to those of NE Kazakhstan, with meaningful differences in declination until the Late Permian, and thereafter become consistent. Thus, the South and West Junggar areas probably experienced contrasting tectonic evolutions, and the Present Junggar Basin cannot be considered as a rigid block during the Late Paleozoic. The meaningful differences in both latitude and rotation of Late Permian poles between South and West Junggar may argue for the importance of post-Permian tectonics (e.g. Triassic to Cenozoic) in Central Asia.

Choulet, F.; Chen, Y.; Wang, B.; Faure, M.; Cluzel, D.; Lin, W.; Xu, B.

2009-12-01

232

Methanogenic burst in the end-Permian carbon cycle  

Science.gov (United States)

The end-Permian extinction is associated with a mysterious disruption to Earth’s carbon cycle. Here we identify causal mechanisms via three observations. First, we show that geochemical signals indicate superexponential growth of the marine inorganic carbon reservoir, coincident with the extinction and consistent with the expansion of a new microbial metabolic pathway. Second, we show that the efficient acetoclastic pathway in Methanosarcina emerged at a time statistically indistinguishable from the extinction. Finally, we show that nickel concentrations in South China sediments increased sharply at the extinction, probably as a consequence of massive Siberian volcanism, enabling a methanogenic expansion by removal of nickel limitation. Collectively, these results are consistent with the instigation of Earth’s greatest mass extinction by a specific microbial innovation.

Rothman, Daniel H.; Fournier, Gregory P.; French, Katherine L.; Alm, Eric J.; Boyle, Edward A.; Cao, Changqun; Summons, Roger E.

2014-01-01

233

Methanogenic burst in the end-Permian carbon cycle.  

Science.gov (United States)

The end-Permian extinction is associated with a mysterious disruption to Earth's carbon cycle. Here we identify causal mechanisms via three observations. First, we show that geochemical signals indicate superexponential growth of the marine inorganic carbon reservoir, coincident with the extinction and consistent with the expansion of a new microbial metabolic pathway. Second, we show that the efficient acetoclastic pathway in Methanosarcina emerged at a time statistically indistinguishable from the extinction. Finally, we show that nickel concentrations in South China sediments increased sharply at the extinction, probably as a consequence of massive Siberian volcanism, enabling a methanogenic expansion by removal of nickel limitation. Collectively, these results are consistent with the instigation of Earth's greatest mass extinction by a specific microbial innovation. PMID:24706773

Rothman, Daniel H; Fournier, Gregory P; French, Katherine L; Alm, Eric J; Boyle, Edward A; Cao, Changqun; Summons, Roger E

2014-04-15

234

Sedimentology and depositional environments of Lower Permian Yeso Formation in northwestern New Mexico  

Energy Technology Data Exchange (ETDEWEB)

The northwesternmost exposures of the Lower Permian (Leonardian) Yeso Formation are in uplifts that bound the southern half of the San Juan basin in northwestern New Mexico. The Yeso comprises the Meseta Blanca member and overlying San Ysidro Member. The latter is called the Los Vallos Member in the southern part of the study area. The Meseta Blanca consists of cross-stratified and horizontal to wavy-bedded sandstones of eolian-dune, sand-sheet, and sabkha origin. These facies also occur in the San Ysidro (Los Vallos), which additionally includes mud-draped, ripple-laminated sandstones of supratidal mud-flat origin, gypsiferous sandstones and siltstones of sabkha origin, and evaporite-carbonate rocks of intertidal to marine-shelf origin. Paleocurrent analysis indicates that eolian dunes in the Meseta Blanca migrated southward in the northern part of the study area. These dunes may have been extensions of the DeChelly Sandstone erg to the northwest. Dunes in the southern part of the study area shifted under variable north-south winds. This variability may reflect a seasonal onshore/offshore wind regime. Lateral facies changes in the San Ysidro (Los Vallos) indicate a juxtaposition of eolian-dune and sand-dominated sabkha environments in the northern part of the study area, with coastal-sabkha, tidal, and shelf environments in the southern part. Eolian dunes prograded southward over coastal sabkhas at least 12 times during deposition of the Yeso. A northward shift of all facies during middle San Ysidro deposition suggests a marine transgression from the south.

Stanesco, J.D. (Geological Survey, Denver, CO (USA))

1989-09-01

235

A Major Unconformity Between Permian and Triassic Strata at Cape Kekurnoi, Alaska Peninsula: Old and New Observations on Stratigraphy and Hydrocarbon Potential  

Science.gov (United States)

A major angular unconformity separates carbonates and shales of the Upper Triassic Kamishak Formation from an underlying unnamed sequence of Permian agglomerate, volcaniclastic rocks (sandstone), and limestone near Puale Bay on the Alaska Peninsula. For the first time, we photographically document the angular unconformity in outcrop, as clearly exposed in a seacliff ~1.3 mi (2.1 km) west of Cape Kekurnoi in the Karluk C?4 and C?5 1:63,360-scale quadrangles. This unconformity is also documented by examination of core chips, ditch cuttings, and (or) open-hole electrical logs in two deep oil-and-gas-exploration wells (Humble Oil & Refining Co.?s Bear Creek No. 1 and Standard Oil Co. of California?s Grammer No. 1) drilled along the Alaska Peninsula southwest of Puale Bay. A third well (Richfield Oil Corp.?s Wide Bay Unit No. 1), south of and structurally on trend with the other two wells, probed deeply into the Paleozoic basement, but Triassic strata are absent, owing to either a major unconformity or a large fault. Here we briefly review current and newly acquired data on Permian and Triassic rocks of the Puale Bay-Becharof Lake-Wide Bay area on the basis of an examination of surface and subsurface materials. The resulting reinterpretation of the Permian and Triassic stratigraphy has important economic ramifications for oil and gas exploration on the Alaska Peninsula and in the Cook Inlet basin. We also present a history of petroleum exploration targeting Upper Triassic reservoirs in the region.

Blodgett, Robert B.; Sralla, Bryan

2008-01-01

236

Sedimentology and Depositional Environments of the Lower Permian Yeso Formation, Northwestern New Mexico (Chapter M).  

Science.gov (United States)

In the Nacimiento Mountains of northwestern New Mexico, the Lower Permian (Leonardian) Yeso Formation is divided into a lower member, the Meseta Blanca, and an upper member, the San Ysidro. The report describes lithofacies of the Yeso Formation in northwe...

J. D. Stanesco

1991-01-01

237

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

238

Permian biogeography of the Indian subcontinent with special reference to the marine fauna  

Science.gov (United States)

Permian biogeography of the Indian subcontinent is discussed in the light of brachiopods and associated fossils from different localities. The discussion is based primarily on the Permian "biome" concept of Waterhouse and Bonham-Carter (1975), wherein three biomes are proposed: group A of subpolar, group B of temperate, and group C of tropical character. Data on the occurrence of Permian brachiopods and associated fossils are given for the Salt Range, Karakoram, and Himalayan regions of India, Nepal, Bhutan, Tibet, and Peninsular India with respect to the age of the fauna. Marine Permian localities of the Himalayan region include those of Ladakh, Zanskar, Lahaul and Spiti, Kashmir, Bhadarwah-Bhallesh-Chamba, Kinnaur, Garhwal, Kumaun, Darjeeling, Sikkim, and Arunachal Pradesh. Permian marine localities of Peninsular India, which forms a part of central Gondwanaland, include those of Bap, Badhaura, Umaria, Manendragarh, and Daltonganj, where marine transgression occurred in Early Permian time. The faunas of these localities are discussed with respect to their age, which falls into two groups, Early and Late Permian. It is suggested that widespread colder climatic conditions prevailed in the Indian subcontinent during the early Early Permian. Similar conditions continued in most of the localities until the late Early Permian, except at west Karakoram (Shaksgam valley), Zanskar, north Tibet (central and western part), and the Salt Range. However, during the Late Permian, climatic conditions were varied. Cold climatic conditions prevailed in north Tibet (central part), Kumaun Tethyan Himalaya, and south Tibet; temperate conditions occurred in west Karakoram (Shaksgam valley), Zanskar, Lahaul and Spiti, Bhadarwah-Bhallesh-Chamba, north Nepal, and north Sikkim; and tropical conditions occurred in the Salt Range, east Karakoram, Ladakh, Kashmir, and north Tibet (western and eastern parts). At a few localities there appear to be some anomalies that might be due to lack of stratigraphical details and/or lack of detailed faunal investigations. An analysis of the Permian fauna of the Indian subcontinent reveals that the fauna belongs to one single biogeographic province, the Gondwana province. The northern boundary of this biogeographic province passes through the Karakoram Pass, Bangong Lake, and the Nujiang River. The Gondwana biogeographic province, further, shows two subprovinces, the Himalayan and the Tibetan.

Singh, Trilochan

239

Deep-seated salt dissolution in the Delaware basin, Texas and New Mexico  

International Nuclear Information System (INIS)

Patterns of salt dissolution in the Delaware Basin are related to the bedrock geometry and hydrology that developed following uplift, tilting, and erosion in the late Cenozoic, and the greatest volume of salt has been removed since that time. During the Permian, some salt was dissolved from the top of the Castile Formation before deposition of the Salado Formation and from the top of the Salado before deposition of the Rustler Formation. In addition, some salt dissolution occurred after the Permian and before the Cretaceous. Post-uplift surface dissolution has progressed across the Delaware Basin from south to north and west to east and generally down the regional dip. Deep-seated dissolution has occurred around the margin of the basin where the Capitan Limestone aquifer is in contact with the Permian evaporites and within the basin where selective dissolution in the lower Salado has undercut the overlying salt beds of the middle and upper Salado. Dissolution has not advanced down regional dip uniformly but has left outliers of salt and has progressed selectively into structurally predisposed areas. This selective advance has significance for the stability of the U.S. Department of Energy's Waste Isolation Pilot Plant (WIPP) site

1981-01-01

240

Stratigraphy and facies analysis of the Upper Carboniferous to Lower Permian Canyon Fiord, Belcher Channel, and Nansen Formations, southwestern Ellesmere Island  

Energy Technology Data Exchange (ETDEWEB)

This study deals with the stratigraphy and facies analysis of the Upper Carboniferous to Lower Permian Canyon Fiord, Belcher Channel, and Nansen formations, Raanes Peninsula, southwestern Ellesmere Island. These formations probably display the most promising upper Paleozoic hydrocarbon possibilities in the Sverdrup Basin. Lithostratigraphic, biostratigraphic, and petrographic data gathered from 13 surface sections are integrated to provide a concise paleoenvironmental framework that will be useful for both broader scale basin analysis and smaller scale detailed investigations. Sediments of the studied formations were deposited within four broad sedimentary settings: syntectonic red beds, coastal plain fluvial system, shelf, and basinal slope. The main environmental factors controlling carbonate and clastic sedimentation on Raanes Peninsula included tectonically-controlled first order sea level fluctuations, eustatically-controlled fourth- or fifth-order sea level oscillations promoting shelf cyclicity, episodic synsedimentary rifting pulses and associated block faulting, arid to semi-arid climate, low clastic influx from basin-frining rivers, low tidal range, and occasional storms. Indirect factors, such as carbonate production, early submarine cementation, and meteoric diagenesis, played an equally significant role. Two types of carbonate buildups were observed in the studied succession: Palaeoaplysina - phylloid algal buildups (small patch reef, wide tabular bank, large reef-mound), and Tubiphytes - bryozoan buildup (small patch reef). Several processes, acting simultaneously, were responsible for the internal growth of buildups. 201 refs., 58 figs., 3 tabs.

Beauchamp, B.

1987-01-01

 
 
 
 
241

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

242

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 S...

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

2008-01-01

243

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.

244

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

245

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

International Nuclear Information System (INIS)

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

246

Tectonic evolution of the Larne Basin  

Energy Technology Data Exchange (ETDEWEB)

The Larne Basin lies in the Midland Valley terrane between Northern Ireland and SW Scotland. A proportion of the basin lies onshore Northern Ireland, with an offshore continuation into the North Channel seaway. The basin is orientated NE-SW, and the sedimentary basin fill thickens to the west. Extensional faults in the south of the basin dip generally to the east, those in the north to the northwest. Preserved sediments range in age from Carboniferous to Tertiary, but are predominantly Permo-Triassic. Integration of seismic interpretations, well data and outcrop fault and fracture measurements has revealed a number of Mesozoic and Cenozoic tectonic events. Late Carboniferous N-S compression was followed by a major phase of regional early Permian ENE-WSW/NE-SW extension. ENE-WSW extension followed in the late Triassic and early Jurassic with post-early Jurassic to late Cretaceous minor subsidence and uplift resulting in a major erosional unconformity between the Lower Lias and Upper Cretaceous Greensand and Chalk. (author)

Shelton, Rob [Queen`s Univ., Geology Dept., Belfast, Northern Ireland (United Kingdom)

1997-12-31

247

Direct shear testing on rock core samples from G. Friemel No. 1 (PD-5) well, Palo Duro Basin, Texas: unanalyzed data  

Energy Technology Data Exchange (ETDEWEB)

This report contains the direct shear strength testing procedure and testing results of rock core samples from the G. Friemel No. 1 well in the Permian Basin. Attachments include G. Friemel 1239.4 test results as well as G. Friemel 2680.7 test results. These data are preliminary. They have not been analyzed or evaluated.

1985-01-01

248

Direct shear testing on rock core samples from the Detten No. 1 (PD-6) 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 Detten No. 1 Well in the Permian Basin. Attachments include Detten 1200.2 test results as well as Detten 2680.7 test results. These data are preliminary. They have not been analyzed or evaluated. 3 figures.

1984-08-01

249

Catagenesis of organic matter of oil source rocks in Upper Paleozoic coal formation of the Bohai Gulf basin (eastern China)  

Energy Technology Data Exchange (ETDEWEB)

The Bohai Gulf basin is the largest petroliferous basin in China. Its Carboniferous-Permian deposits are thick (on the average, ca. 600 m) and occur as deeply as 5000 m. Coal and carbonaceous shale of the Carboniferous Taiyuan Formation formed in inshore plain swamps. Their main hydrocarbon-generating macerals are fluorescent vitrinite, exinite, alginite, etc. Coal and carbonaceous shale of the Permian Shanxi Formation were deposited in delta-alluvial plain. Their main hydrocarbon-generating macerals are vitrinite, exinite, etc. The carbonaceous rocks of these formations are characterized by a high thermal maturity, with the vitrinite reflectance R{sub 0} > 2.0%. The Bohai Gulf basin has been poorly explored so far, but it is highly promising for natural gas.

Li, R.X.; Li, Y.Z.; Gao, Y.W. [Changan University, Xian (China)

2007-05-15

250

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

2012-07-01

251

Oil and gas in the Junggar basin the People`s Republic of China  

Energy Technology Data Exchange (ETDEWEB)

The Junggar Basin, located in the north of Xinjiang, China, and with an area of 130000 km{sup 2}, is a compressional inland basin formed during the late Hercynian. Exploration and development of oil and gas in the basin has been run by Karamay Oil & Gas Corporation (KOC). The basin has two basements, Precambrian crystalline basement and Early to Middle Hercynian fold basement. Maximum sedimentary cover from Late Permian to Quaternary is above 20,000m thick. There are six source rocks developed in Carboniferous, Permian, Triassic, Jurassic, Cretaceous and Paleogene, respectively. Of the most important Permian and Jurassic source rocks, the former is oil-prone and the latter gas-prone. Total oil and gas resources in the basin are about 80-100x10 8t. In the mid 1950`s, Karamay oilfield, which is closely, related to the overthrust belt, was discovered in the northwest margin of the basin. Since then, the proven oil reserves in the up to 250km long overthrust belt with Karamay oilfield being the center can be compared to the Cordilleran Overthrust Belt in North America. By the end of 1993, fifteen oil and gas fields have been discovered, and the oil and gas reservoirs are found in all strata from Carboniferous to Tertiary except Cretaceous. The reservoir lithologies are mainly low mature sandstones, conglomerates as well as late Paeleozoic volcanic rocks. The proven reserves are dominantly distributed in the northwest margin, which illustrated unbalanced exploration. The exploration degree in most part of the basin is still low. Since 1961, the crude oil production has been increasing year after year.

Zhang Ji-Yi [Karamay Oil Corp., Xinjing (China)

1995-08-01

252

Permian nonmarine bivalve zonation of the East European platform  

Science.gov (United States)

New finds and revision of available collections of nonmarine bivalves provided grounds for development of a zonal scale for terrestrial sequences of the Permian System based on species belonging to the genus Palaeomutela Amalitzky, 1891, which are characterized by regular changes in the structure of the shell hinge. The scale includes two parallel zonal successions that are based on the stratigraphic distribution and evolutionary trends of two morphological lineages of the genus. The zonal succession based on development of the P. umbonata group (dwellers of mobile waters and silty-psammitic substrates) includes 11 range zones: stegocephalum, ovatiformis, umbonata, quadriangularis, krotowi, wohrmani, numerosa, ulemensis, keyserlingi, curiosa, golubevi. The zonal succession based on development of the P. castor group (dwellers of calm waters and silty-pelitic substrates) includes eight range zones: larae, castor, olgae, doratioformis, marposadica, fischeri, obunca, amalitzkyi. The proposed zonal units are correlated with scales based on ostracod, fish, and tetrapod fossils. New species Palaeomutela golubevi sp. nov. and P. amalitzkyi sp. nov. are described with the extended diagnosis of the genus Palaeomutela.

Silantiev, V. V.

2014-01-01

253

Late Permian brachiopoda fauna in north-western Iran  

Scientific Electronic Library Online (English)

Full Text Available SciELO Colombia | Language: English Abstract in spanish La secuencia marina del Pérmico superior en el noroeste de Irán y el este de Azerbaiyán, sección estatigráfica de Zal, fue seleccionada para este estudio de braquiópodos. Las muestras fueron tomadas en las formaciones Ali Bashi y Jolfa. Se reconocieron 27 especies de 13 géneros de braquiópodos en es [...] te análisis. Las muestras recolectadas fueron comparadas con sus similares de otras regiones de Irán y de la región del Tetis, lo que sugirió el período de tardío de Dzhulfan como la proveniencia de estos depósitos. Los braquiópodos reconocidos en este trabajo pertenecen a las familias de Athyris, Rhynconellida, Productida y Strophomenida. Abstract in english The Late Permian marine sequence in the north- west of Iran, in eastern Azerbaijan province in the Zal stratigraphic section, was selected for studying brachiopods. Samples were collected from the Ali Bashi and Jolfa Formation.S. Twenty-seven species from 13 brachiopoda genera were recognised in thi [...] s study.The recognised fossil community was compared to brachiopod communities in some regions of Iran and the Tethyan region, suggesting the Late Dzhulfian period as the age for the deposits being studied. Recognized brachiopods belonge to the orders Athyris, Rhynconellida, Productida and Strophomenida.

Yousefirad, Mostafa; Khamooshi, Touran; Shaabanian, Rahim.

254

Radon in the Creswell Crags Permian limestone caves  

International Nuclear Information System (INIS)

An investigation of radon levels in the caves of Creswell Crags, Derbyshire, an important Site of Special Scientific Interest (SSSI) shows that the Lower Magnesian Limestone (Permian) caves have moderate to raised radon gas levels (27-7800 Bq m-3) which generally increase with increasing distance into the caves from the entrance regions. This feature is partly explained in terms of cave ventilation and topography. While these levels are generally below the Action Level in the workplace (400 Bq m-3 in the UK), they are above the Action Level for domestic properties (200 Bq m-3). Creswell Crags has approximately 40,000 visitors per year and therefore a quantification of effective dose is important for both visitors and guides to the Robin Hood show cave. Due to short exposure times the dose received by visitors is low (0.0016 mSv/visit) and regulations concerning exposure are not contravened. Similarly, the dose received by guides is fairly low (0.4 mSv/annum) due in part to current working practice. However, the risk to researchers entering the more inaccessible areas of the cave system is higher (0.06 mSv/visit). This survey also investigated the effect of seasonal variations on recorded radon concentration. From this work summer to winter ratios of between 1.1 and 9.51 were determined for different locations within the largest cave system

2002-01-01

255

A taphonomic model for the Mesosauride assemblage of the Irati Formation (Paraná Basin, Brazil)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The Irati Formation (Permian, Paraná Basin, Brazil) is made up of a succession of black bituminous and nonbituminous shales and mudstones with interbedded carbonate layers, which record deposition in marine environments. Mesosaur remains are abundant at several sites in this formation, where they occur preserved in centimetre- thick beds and displaying various degrees of skeletal disarticulation. This paper seeks to establish a model to explain the processes that generated the mesosaurian ta...

2003-01-01

256

Bioessential element-depleted ocean following the euxinic maximum of the end-Permian mass extinction  

Science.gov (United States)

We describe variations in trace element compositions that occurred on the deep seafloor of palaeo-superocean Panthalassa during the end-Permian mass extinction based on samples of sedimentary rock from one of the most continuous Permian-Triassic boundary sections of the pelagic deep sea exposed in north-eastern Japan. Our measurements revealed low manganese (Mn) enrichment factor (normalised by the composition of the average upper continental crust) and high cerium anomaly values throughout the section, suggesting that a reducing condition already existed in the depositional environment in the Changhsingian (Late Permian). Other redox-sensitive trace-element (vanadium [V], chromium [Cr], molybdenum [Mo], and uranium [U]) enrichment factors provide a detailed redox history ranging from the upper Permian to the end of the Permian. A single V increase (representing the first reduction state of a two-step V reduction process) detected in uppermost Changhsingian chert beds suggests development into a mildly reducing deep-sea condition less than 1 million years before the end-Permian mass extinction. Subsequently, a more reducing condition, inferred from increases in Cr, V, and Mo, developed in overlying Changhsingian grey siliceous claystone beds. The most reducing sulphidic condition is recognised by the highest peaks of Mo and V (second reduction state) in the uppermost siliceous claystone and overlying lowermost black claystone beds, in accordance with the end-Permian mass extinction event. This significant increase in Mo in the upper Changhsingian led to a high Mo/U ratio, much larger than that of modern sulphidic ocean regions. This trend suggests that sulphidic water conditions developed both at the sediment-water interface and in the water column. Above the end-Permian mass extinction horizon, Mo, V and Cr decrease significantly. On this trend, we provide an interpretation of drawdown of these elements in seawater after the massive element precipitation event during the end-Permian maximum development of the reducing water column. A decrease in the Mo/U ratio despite enrichment of Mo and U also supports that of Mo. Calculations of the total amounts of these elements precipitated compared with the global seawater inventory suggest that when more than 6-10% of the global ocean became euxinic as much as the study section, most of the dissolved elements would precipitate into sediments, resulting in a global element-depleted seawater condition. Mo, V, and Cr act as bioessential elements for both primary producers and animals. The continuing reducing water column and the lack of bioessential elements could have had a considerable effect on primary producer turnover and marine life metabolism not only in the pelagic environment, but also in surrounding marine environments.

Takahashi, Satoshi; Yamasaki, Shin-ichi; Ogawa, Yasumasa; Kimura, Kazuhiko; Kaiho, Kunio; Yoshida, Takeyoshi; Tsuchiya, Noriyoshi

2014-05-01

257

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

CERN Document Server

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

258

Influence of localised igneous activity on cleat dawsonite formation in Late Permian coal measures, Upper Hunter Valley, Australia  

Energy Technology Data Exchange (ETDEWEB)

Stable ({delta}{sup 13}C and {delta}{sup 18}O) and radiogenic {sup 87}Sr/{sup 86}Sr isotopic data have been used to investigate the origin of cleat dawsonite (NaAlCO{sub 3}(OH){sub 2}) in the Late Permian Wittingham Coal Measures of the Upper Hunter region in the Sydney Basin, New South Wales. The {delta}{sup 13}C{sub PDB} values have a narrow range (-1.7%% to +2.4%%), with an average of +0.3%%, suggesting a magmatic source for the carbon. In contrast, {delta}{sup 18}O{sub SMOW} values have a wide range (+13.6%% to +19.8%%), and decrease systematically with decreasing distance from a major intrusion. This systematic variation reflects establishment of localised hydrothermal cells. Water-rock interaction between fluids associated with these hydrothermal cells, and Rb-poor volcaniclastic detritus in the coal measures, produced mantle-like {sup 87}Sr/{sup 86}Sr (0.705032 to 0.706464) in the dawsonite. (author)

Golab, Alexandra N.; Palamara, Daniel R. [School of Civil, Mining and Environmental Engineering, University of Wollongong, NSW, 2522 (Australia); Carr, Paul F. [School of Earth and Environmental Sciences, University of Wollongong, NSW, 2522 (Australia)

2006-04-03

259

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese 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. Abstract in english 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 analy [...] sis 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.

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

260

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

2004-03-01

 
 
 
 
261

Sedimentary facies reconstruction and kinematic restoration of tight gas fields. Studies from the Upper Permian in Northwestern Germany  

Energy Technology Data Exchange (ETDEWEB)

Outstanding Ph.D. thesis nominated for a Springer Theses Prize by the RWTH Aachen University, Germany. A multi-disciplinary study with application in the oil and gas industry. Approx. 60 color figures. The thesis of Anna Alexandra Vackiner focuses on the geometric architecture and tectonic evolution of the Permian series, combining seismic interpretation (3D block), field studies in an analogue basin (Panamint Valley in California), as well as 2D restoration of representative cross sections through time in order to illustrate the complex interaction between multiphase extension, inversion and salt diapirism. It will be of major interest for exploration geologists involved in tectonically complex areas. - Francois Roure, August 2012 This thesis improves the understanding and localization of the Upper Rotliegend II tight gas reservoir rock facies. It provides insights into the detailed Upper Rotliegend II palaeo-topography and local tectonically induced sediment thickness changes prior to a multi-phase tectonic overprinting. The research presented in this study further focuses on the tectonically induced synsedimentary facies distribution in transtensional continental settings on the basis of a comparison with a modern field analogue, which enables a detailed analysis of the reservoir rock's distribution and its properties. The study is rounded off with an analysis of the influence of the multiphase tectonic overprinting on the mature Upper Rotliegend II reservoir rocks.

Vackiner, Anna Alexandra [RWTH Aachen Univ. (Germany). Energy and Mineral Resources Group

2013-11-01

262

Ichnology of fine-grained mixed carbonate-siliciclastic turbidites, Wood River Formation, Pennsylvanian-Permian south-central Idaho  

Energy Technology Data Exchange (ETDEWEB)

In south-central Idaho, the Wood River Formation (Pennsylvanian-Permian) contains a stratigraphic megacycle over 2,000 m thick that is composed of fine-grained mixed carbonate-siliciclastic turbidites. Complete and partial (Bouma) turbidite structural sequences in these rocks are arranged in upward thinning cycles 15 to 30 m thick in which top-cut-out (Ta-c) turbidite facies in the lower part grade vertically into base-cut-out (Td-f) turbidites in the upper part. These cycles are interpreted to represent the autocyclic lateral migration of turbidite lobes. A mixed trace fossil assemblage of pascichnia and fordinichnia are present in these rocks and can be separated into pre-depositional and post-turbidite ichnocoenoses. Quiet-water, pre-turbidite deposits are dark-colored, laminated, and carbonaceous, and represent anoxic to dysoxic inter-turbidite basinal conditions; they contain only Chondrites traces. Turbidity currents introduced oxygenated bottom water which fostered the temporary development of a post-turbidite ichnocoenose of pascichnia which is best developed in the medial portion of turbidite beds and lobes. Trace fossil tiering shows that a post-turbidite ichnocoenose of fodinichnia also developed, and persisted after the disappearance of pascichnia. Animals that produced the fodinichnial traces probably were part of an autochthonous benthic fauna rather than a short-lived allochthonous fauna. They may have migrated with the slowly avulsing turbidite lobes and exploited allochthonous oxygen and the carbonaceous food supply.

Burton, B.R. (Norcen Energy Resources Ltd., Calgary, Alberta (Canada)); Link, P.K. (Idaho State Univ., Pocatello (United States))

1991-06-01

263

U Pb ages and source composition by Hf-isotope and trace-element analysis of detrital zircons in Permian sandstone and modern sand from southwestern Australia and a review of the paleogeographical and denudational history of the Yilgarn Craton  

Science.gov (United States)

Detrital zircons from the Permian Collie Coal Measures and modern sands on the northern part of the Albany Province have been analysed for U-Pb ages by a laser ablation microprobe-inductively coupled plasma mass spectrometer (LAM-ICPMS) and for Hf-isotope compositions by a laser ablation microprobe multi-collector inductively coupled plasma mass spectrometer (LAM-MC-ICPMS). Trace elements were determined by analysis on the electron microprobe (EMP) and the ICPMS's. This combination of techniques makes it possible to determine for each grain not only the age but the nature and source of the host magma, whether crustal or juvenile mantle, and a model age ( TDM) based on a depleted-mantle source, which gives a minimum age for the source material of the magma from which the zircon crystallised. The integrated analysis, applied to suites of detrital zircon, gives a more distinctive, and more easily interpreted, picture of crustal evolution in the provenance area than age data alone. Zircons from Permian and Triassic sediments already analysed for U-Pb ages by a sensitive high-resolution ion microprobe (SHRIMP) were also analysed for Hf isotopes and trace elements. Zircons from Collie and Permian and Early Triassic rocks of the northern Perth Basin have an age spectrum with a peak at about 1200 Ma that can be traced to the Albany Province. Differences, however, in Hf-isotope composition indicate that the Collie Coal Measures and the northern Perth Basin sandstones were not derived from the northern part of the Albany Province or from the coastal strip of felsic granitoids. The Perth Basin samples have a second peak age of 600-500 Ma that can be traced to the Leeuwin Block. One of the modern sands has a major peak at 2616 Ma that can be traced to the Yilgarn Craton. Compiled with previously published U-Pb zircon age spectra, the analyses provide insights into the paleogeographical history. The Yilgarn Craton sloped from the north at 1700 Ma, from the southeast at 1350-1140 and 490 Ma, its eastern part to the east at 300 Ma, and the southern part to the northwest from the Albany Province at 300-255 Ma. Denudational data from apatite fission-track analysis and vitrinite-reflectance studies suggest that the Yilgarn Craton was covered by a ˜5-km-thick blanket of Permian and Mesozoic sedimentary rock that was almost entirely removed by the Cenozoic, possibly because the craton was situated between the shoulders of rift systems that grew into the eastern and southeastern Indian Ocean. Ordovician, Permian, Early Triassic, and Quaternary sediment of the Perth Basin came from Proterozoic orogens. Only the Late Permian sample contains significant populations of Archean (Yilgarn) zircons but whether they came direct from the craton or were recycled from the postulated sedimentary cover is not known. The increased influx of sediment during the Jurassic matched by a peak in the denudation rate would seem to require a primary supply from the craton. This question could be resolved by dating zircon from the rapidly accumulated Jurassic formations.

Veevers, J. J.; Saeed, A.; Belousova, E. A.; Griffin, W. L.

2005-01-01

264

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

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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 T...

J Loegering, Markus; Anka, Z.; Autin, Julia; Di Primio, Rolando; Marchal, Denis; F Rodriguez, Jorge; Franke, D.; Vallejo, Eduardo

2013-01-01

265

Salt as a 3D element in structural modelling - example from the Central European Basin System  

Science.gov (United States)

The Central European Basin System (CEBS) covers the northern part of Central and Western Europe and contains up to 12 km of Permian to Cenozoic deposits. Initiated in the Early Permian, the Central European Basin System accumulated Lower Permian clastics overlain by significant amount of Upper Permian (Zechstein) salt. Post-Permian differentiation of the basin system was controlled by several phases of tectonic activity. These tectonic phases not only provoked regional shifts in subsidence and erosion but also triggered movements of the Upper Permian (Zechstein) salt. Salt rise strongly influenced the Meso-Cenozoic structural evolution in terms of mechanical decoupling of the sedimentary cover from its basement. As a result of several phases of salt tectonics, the CEBS displays a wide variety of salt structures (walls, diapirs and pillows). In order to investigate the interaction of salt movements, deposition and tectonics, the 3D structural model of the CEBS has been constructed covering the entire salt basin (Northern and Southern Permian basins). Seismic interpretation and 3D backstripping have been used to investigate both the present-day structure and the evolution of the CEBS. 3D backstripping includes 3D salt redistribution in response to the changing load conditions in the salt cover. The results of 3D modelling of salt movements and seismic data indicate that the primary initiation of salt movements occurred during the Triassic. The Triassic regional extensional event initiated a phase of salt movements within the coeval depocenters of the CEBS, such as the Glueckstadt Graben, the Horn Graben, the Fjerritslev Trough and the adjacent Himmerland Graben in Denmark, as well as the Polish Basin. The Early Triassic (Buntsandstein) and the Late Triassic (Middle-Late Keuper) extensional events triggered strongest salt movements within the central part of the Glueckstadt Graben. During the Late Jurassic-Early Cretaceous, major erosion regionally truncated the study area. The magnitude of Late Jurassic-Early Cretaceous erosion is declining towards the margins of the basin system. In the Late Jurassic-Early Cretaceous, an increased intensity of salt movement influenced the Central Graben, the Lower Saxony Basin and the Pompeckj Block. This phase of growth of salt structures is mostly related to Late Jurassic-Early Cretaceous extensional/transtensional tectonics. The late Early Cretaceous-early Late Cretaceous is characterized by a tectonic quiescence without strong salt movements. A further regional phase of salt tectonics was triggered by Late Cretaceous-Early Tertiary inversion affecting almost the entire Central European Basin System in terms of renewed salt movements. At that time, thick-skinned tectonics affecting the basement is observed along the Elbe Fault System and the Teisseyre-Tornquist Zone where compressional deformations are localized. In contrast, a thin-skinned character of salt movements is prevailing north of the Elbe Fault System. Post-inversion Cenozoic subsidence was accompanied by salt movements, related either to diapiric rise due to regional shortening and/or to local almost E-W directed extension. The Tertiary phase of salt movements was especially prominent within the marginal troughs of the Glueckstadt Graben.

Maystrenko, Y. P.; Scheck-Wenderoth, M.; Bayer, U.

2010-12-01

266

Depositional evolution of a reef-dominated Upper Permian carbonate platform, Wegener Halvoe Formation, Karstryggen area, East Greenland  

Energy Technology Data Exchange (ETDEWEB)

The Wegener Halvoe Formation carbonate platform in the Karstryggen area consists of three third order depositional sequences that formed in response to three Kazanian sea level cycles. Pinning point curves for the sub-aerial exposure surfaces separating the depositional sequences quantify the amplitude of the relative sea level fluctuations in the range of 70-140 m. The Karstryggen platform developed on top of a karstified older Permian carbonate platform and pre-depositional relief was locally exceeding 70 m. The pre-depositional relief influenced deposition in all three sequences. Algal-cement buildups formed over karst pinnacles and merged during time to form a N-S trending barrier dissected by deep fluvially modified karst channels. Peritidal carbonates formed behind the barrier whereas off platform sedimentation was dominated by thin transgressive siliciclastics overlain by shallow marine algal-foraminifer grain-stones in the first two sequences. During the last sea level cycle pro-grading oolitic grain-stones formed basin-wards of the algal-cement buildups. Transgressive systems tracts are thin and often dominated by condensed siliciclastic units in off platform areas and palaeolows. Over palaeotopographic highs it consists of aggrading algal cement-stones. High-stand deposits are limited to palaeotopographic elevated areas and consist of algal cementstones along the basin margin and shallow sub-tidal to inter-tidal carbonates and evaporites in the platform area. Outside these areas carbonate deposition took place during falling sea level, and during deposition of the first two sequences thin laterally extensive units of shallow marine grain-stones were deposited directly on top of deeper marine siliciclastics. During the final sea level fall, thick pro-grading units of oolitic grain-stones were deposited. (au) Appendix no. 3. 28 refs.

Stemmrik, L.

1996-12-31

267

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

2011-12-01

268

Fracture pattern of the Illawarra Coal Measures, southeastern Sydney Basin  

Energy Technology Data Exchange (ETDEWEB)

This paper reports the findings of extensive fracture mapping of the Illawarra Coal Measures exposed along the coastal platforms and adjacent cliffs, between Coalcliff and Wollongong. Fracture mapping has enabled identification of four phases of deformation active from the time of Late Permian deposition until the present. Syn-depositional mild warping and normal faulting has been recognised for the southeastern Sydney Basin and was confirmed by the present study. Regional joint systems formed after deposition and developed in three major directions. All fracture sets were reactivated with common strike-slip movements. 22 refs., 1 fig.

Memarian, H.; Fergusson, C.L. [University of Wollongong, Wollongong, NSW (Australia). Dept. of Geology

1994-12-31

269

Source rocks of the Sub-Andean basins  

Energy Technology Data Exchange (ETDEWEB)

Seven source rock systems were mapped using a consistent methodology to allow basin comparison from Trinidad to southern Chile. Silurian and Devonian systems, deposited in passive margin and intracratonic settings, have fair-good original oil/gas potential from central and northern Bolivia to southern Peru. Kerogens range from mature in the foreland to overmature in the thrust belt. Permian to Carboniferous deposition in local restricted basins formed organic-rich shales and carbonates with very good original oil/gas potential, principally in northern Bolivia and southern Peru. Late Triassic to early Jurassic marine shales and limestones, deposited in deep, narrow, basins from Ecuador to north-central maturity. Locally, in the Cuyo rift basin of northern Argentina, a Triassic lacustrine unit is a very good, mature oil source. Early Cretaceous to Jurassic marine incursions into the back-arc basins of Chile-Argentina deposited shales and limestones. Although time transgressive (younging to the south), this system is the principal source in southern back-arc basins, with best potential in Neuquen, where three intervals are stacked A late Cretaceous marine transgressive shale is the most important source in northern South America. The unit includes the La Luna and equivalents extending from Trinidad through Venezuela, Colombia, Ecuador, and into northern Peru. Elsewhere in South America upper Cretaceous marine-lacustrine rocks are a possible source in the Altiplano and Northwest basins of Bolivia and Argentina. Middle Miocene to Oligocene source system includes shallow marine, deltaic, and lacustrine sediments from Trinidad to northern Peru.

Raedeke, L.D. (Chevron Overseas Petroleum Inc., San Ramon, CA (United States))

1993-02-01

270

Sedimentary facies and environmental ichnology of a ?Permian playa-lake complex in western Argentina  

Science.gov (United States)

A moderately diverse arthropod icnofauna occurs in ?Permian ephemeral lacustrine deposits of the Paganzo Basin that crop out at Bordo Atravesado, Cuesta de Miranda, western Argentina. Sedimentary successions are interpreted as having accumulated in a playa-lake complex. Deposits include three sedimentary facies: (A) laminated siltstone and mudstone: (B) current-rippled cross-laminated very fine grained sandstone: and (C) climbing and wave-rippled cross-laminated fine-grained sandstone deposited by sheet floods under wave influence in the playa-lake complex. Analysis of facies sequences suggests that repeated vertical facies associations result from transgressive regressive episodes of variable time spans. The Bordo Atravesado ichnofauna includes Cruziana problematica, Diplocraterion isp., cf. Diplopadichnus biformis, Kouphichnium? isp., Merostomichnites aicunai, Mirandaichnium famatinense, Monomorphichnus lineatus, Palaeophyeus tubularis, Umfolozia sinuosa and Umfolozia ef. U. longula. The assemblage is largely dominated by arthropod trackways and represents an example of the Scoyenia ichnofacies. Trace fossils are mostly preserved as hypichnial ridges on the soles of facies C beds, being comparatively rare in facies A and B. Ichnofossil preservation was linked to rapid influx of sand via sheet floods entering into the lake. Four taphonomic variants (types 1-4) are recognized, each determined by substrate consistency and time averaging. Type 1 is recorded by the presence of low density assemblages consisting of poorly defined trackways, which suggests that arthropods crawled in soft, probably slightly subaqueous substrates. Type 2 is represented by low to moderate density suites that include sharply defined trackways commonly associated with mud cracks, suggesting that the tracemakers inhabited a firm, desiccated lacustrine substrate. Type 3 displays features of types 1 and 2 and represents palimpsestic bedding surfaces, resulting from the overprint of terrestrial ichnocoenoses over previously formed softground suites. Type 4 differs from type 2 only in that assemblages display a high density of traces, recorded by numerous superimposed trackways, which suggests a major time gap of subaerial exposure before sheet flood entrance. Therefore, type 4 surfaces are mostly interpreted as track imprinted omission surfaces.

Zhang, G.; Buatois, L. A.; Mangano, M. G.; Acenolaza, F. G.

1998-01-01

271

Provenance and structural constraints of the early Permian Nambucca Block (eastern Australia), and implications for the origin of the New England oroclines  

Science.gov (United States)

The late Paleozoic to early Mesozoic southern New England Orogen of eastern Australia exhibits a remarkable omega-shaped orogenic curvature (orocline), but the geodynamic processes responsible for the formation of the orogenic curvatures (oroclines) are still unclear. Oroclinal bending took place during the early Permian, simultaneously with the development of rift-related sedimentary basins (Sydney, Gunnedah and Bowen basins), which bound the oroclines to the west. The Nambucca Block is part of another early Permian rift basin that is situated farther east, in the core of the oroclinal structure. We present new stratigraphic, structural and geochronological data from the Nambucca Block in an attempt to better understand its provenance, tectonic history and its role in the formation of the oroclines. Four phases of folding and associated structural fabrics are recognised in the Nambucca Block. 40Ar/39Ar age of metamorphic micas from the second deformational phase provides a minimum depositional age constraint at 275-265 Ma. This age overlaps with the timing of oroclinal bending, suggesting that the first two phases of deformation resulted from the same mechanism that formed the oroclines. Detrital zircon geochronology (U/Pb ICP-MS ages) of six samples from the Nambucca Block constrains the maximum depositional age of the sequence to 280 Ma. The sedimentary succession, though extremely polymictic, is unimodal in its sources, and is therefore interpreted to consist mainly of recycled detritus from a Devonian-Carboniferous accretionary complex. We propose a model for oroclinal bending involving three stages. The first stage, starting at about 293 Ma and including the deposition of the sequence of Nambucca (i.e. overlaps with the 280-265 Ma time constraint), was associated with formation of rift basins in an extensional backarc setting. This was followed by N-S contraction, which gave rise to second-order oroclinal structures. The third and final stage involved contractional deformation that gave rise to recumbent folds and penetrative sub-horizontal structural fabrics at 275-265 Ma and further tightened the oroclinal structure.

Shaanan, Uri; Rosenbaum, Gideon; Li, Pengfei; Vasconcelos, Paulo; Wormald, Richard

2014-05-01

272

Major phases of salt tectonics within the Central European Basin System  

Science.gov (United States)

The Central European Basin System (CEBS) covers the area of the Southern and Northern Permian basins and contains up to 12 km of Permian to Cenozoic deposits. Initiated in the Early Permian, the Central European Basin System accumulated Lower Permian clastics overlain by significant amount of Upper Permian (Zechstein) salt. Post-Permian differentiation of the basin system was controlled by variable regional stress conditions including Late Triassic extension, a Mid-Late Jurassic-Early Cretaceous regional erosional event, Early Cretaceous transtension and Late Cretaceous-Early Tertiary compression. These tectonic phases not only provoked regional shifts in subsidence and erosion but also triggered the mobilisation of the Zechstein salt which had an important impact on sedimentation and the subsequent deformation of Mesozoic and Cenozoic strata within the CEBS. Salt rise strongly influenced the Meso-Cenozoic structural evolution in terms of mechanical decoupling of the sedimentary cover from its basement. Consequently, the CEBS displays a wide variety of salt structures (walls, diapirs and pillows) with structural amplitudes of up to 9 km. This makes it a classical site to study the interaction of salt movements, deposition and tectonics. A combined approach of subsidence analysis and seismic interpretation has been used to unravel the mechanisms controlling basin evolution and the related salt pathways. Subsidence analysis includes 3D backstripping with salt redistribution in response to the changing load conditions in the salt cover. The results of 3D modelling of salt movements and seismic data indicate that the primary initiation of salt movements occurred during the Triassic. The Triassic regional extensional event initiated a phase of salt movements within the Triassic depocenters of the Central European Basin System, such as the Glueckstadt Graben, Horn Graben, the Fjerritslev Trough and the adjacent Himmerland Graben of the Norwegian-Danish Basin, and the Polish basin. The Early Triassic (Buntsandstein) and the Late Triassic (Middle-Late Keuper) extensional events triggered strongest salt movements within the central part of the Glueckstadt Graben. During the Late Jurassic-Early Cretaceous, major erosion regionally truncated the study area. The magnitude of Late Jurassic-Early Cretaceous erosion is declining towards the margins of the basin system. In the Late Jurassic-Early Cretaceous, an increased intensity of salt movement influenced the Central Graben, the Lower Saxony Basin and the Pompeckj Block. This phase of growth of salt structures is mostly related to Late Jurassic-Early Cretaceous extensional/transtensional tectonics. The late Early Cretaceous-early Late Cretaceous is characterized by a tectonic quiescence without strong salt movements. A further regional phase of salt tectonics was triggered by Late Cretaceous-Early Tertiary inversion affecting almost the entire Central European Basin System in terms of renewed salt movements. At that time, thick-skinned tectonics affecting the basement is observed along the Elbe Fault System where compressional deformations are localized. In contrast, a thin-skinned character of salt movements is prevailing towards the north from the areas of strain localization in the basement. Post-inversion Cenozoic subsidence was accompanied by salt movements, related either to diapiric rise due to regional shortening and/or to local almost E-W directed extension. The Tertiary phase of salt movements was especially prominent within the marginal troughs of the Glueckstadt Graben.

Maystrenko, Yuriy; Scheck-Wenderoth, Magdalena; Bayer, Ulf

2010-05-01

273

Classification of the Central European Basin System (CEBS)  

Energy Technology Data Exchange (ETDEWEB)

The first part of the DGMK-Project 577-2 summarized the results of 36 research projects (DGMK-Research Report 577-2/1), which were funded within the priority research programme of the German Science Foundation (DFG) entitled ''Dynamics of complex sedimentary basins under varying stress conditions by example of the Central European Basin System''. The projects, co-sponsored by the DGMK-Project 577-1, were carried out from 2002 to 2008. The second part of the DGMK-Project 577-2 focused on building a large-scale dynamic 3D structural model of the Central European Basin System (CEBS) by integrating smaller models derived previously and completing the model area by additional data-sources. Based on that model, the structural evolution and the salt movements within the CEBS were reconstructed (GFZ Potsdam, DGMK-Research Report 577-2/2) and - for a selected region within the Southern Permian Basin - the temperature field and the generation and accumulation of hydrocarbons were modeled (RWTH Aachen, DGMK-Research Report 577-2/3). Finally, the CEBS has been classified and compared with other sedimentary basins worldwide (HJ Brink). This research report covers the results of work carried out by HJ Brink within the second part of the DGMK-Project 577-2. The characteristics of the North German Basin are compared with several other important hydrocarbon bearing basins on Earth based on their Field Size Distributions. A weak inverse relationship between the internal complexity of a basin and the half-life time of the basin could be established. The basin modifying tectonics, of which the development of the North German salt domes remains an important part as well as the subsidence and inversion of the Lower Saxony Basin - affected by a questionable intrusion of Bramsche -, and fluid re-distributions due to young processes is being discussed. (orig.)

Brink, H.J.

2010-10-15

274

A new geological map of northwest Ellesmere Island (Sverdrup Basin): Hvitland Peninsula  

Energy Technology Data Exchange (ETDEWEB)

A mapping project was carried out in the Hvitland Peninsula, NW Ellesmere Island, in which the stratigraphic analysis of the Carboniferous and Permian succession was analyzed. The map area included a region of the Upper Paleozoic facies changes. The eastern part of the area is underlain by platformal carbonates. The western part is underlain by basinal mudrocks. The map identifies three distinct structural regions. The map area is significant because of the hydrocarbon potential of similar rocks in the the Sverdrup Basin and the mineral potential (lead zinc) of the platform carbonates, and because segments of the Upper Paleozoic succession on Hvitland Peninsula lie within the oil-window of organic matter maturation.

Mayr, U.; Beauchamp, B.; Harrison, J.C. [Geological Survey of Canada, Calgary, AB (Canada). Inst. of Sedimentary and Petroleum Geology

1997-09-01

275

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

276

Earlier River Basin Planning  

...North Eastern River Basin...into Member State Law. Identify River Basin Districts, International River Basin Districts and competent authorities....Complete initial characterisation of River Basin Districts and International River Basin Districts. Establish registers of Protected...

277

Seismic reflection surveys in central Palo Duro basin  

International Nuclear Information System (INIS)

Seismic reflection surveys have been conducted in the central Palo Duro basin to provide a basis for identifying localities suitable for the emplacement of an underground high level nuclear waste repository. The objectives of this effort were to determine the structure and stratigraphy in the central Palo Duro basin and evaluate the potential for hydrocarbon resources. Of primary interest is the Upper Permian salt section to a depth of about 3000 ft (914 m). Various tests were carried out along a 3 mi (5 km) segment to determine the most appropriate combination of vibrating source and recording parameters. Approximately 130 mi (209 km) of 24-fold CDP stacked data were acquired. The survey lines were tied to test wells in which velocity surveys were conducted. These data were supplemented by about 400 mi (644 km) of available proprietary CDP stacked data. Analysis of these data strongly suggests that central Palo Duro basin has been tectonically stable since Early Permian time. The maximum offset of the basement is about 600 ft (183 m). These basement faults do not appear to affect any strata above. The San Andres Formation and underlying formations can be traced continuously throughout the area surveyed. Available velocity data from various wells in the central Palo Duro basin show few anomalies, confirming the continuity of the reflecting horizons and the tectonic stability of the area. Hydrocarbon potential of the area is presently being evaluated. The preliminary results of this study are in agreement with the stratigraphic correlations among well logs in the Palo Duro basin

1983-03-01

278

Phosphatic Permian rocks of the Adobe Range, Nevada, and their environment of deposition  

Science.gov (United States)

Permian sedimentary rocks in the Adobe range, northern Nevada, are phosphatic, and although the particles of phosphate are relatively more disseminated, they closely resemble the rocks of the Phosphoria Formation. In the northern Adobe Range, where the entire Permian sequence is approximately correlative with the Phosphoria Formation, it is 200 m thick and averages 1.7 percent P2O5 . In the southern Adobe Range, the Permian sequence is more than 1,700 m thick, and the upper half which is roughly correlative with the Phosphoria Formation averages more than 2 percent P2O5. Some thin beds in rocks of Permian age contain more than 20 percent P2O5. Phosphatic rocks of the Adobe Range were deposited in shallow water among islands in the western part of the epicontinental Phosphoria sea. The continental margin and the open ocean lay far to the west. At the same time, the Phosphoria Formation was being deposited in the eastern and central parts of the Phosphoria sea. Theories based on the work of Kasakov done in 1937 relating phosphate deposition directly to sites of upwelling oceanic waters are questioned. Nondeposition of diluent materials such as detritus and carbonate is probably of more importance in producing phosphate in economic concentrations than is geographic position with respect to upwelling waters.

Ketner, Keith Brindley

1979-01-01

279

Simulated Modes Of Variability In the Permian (251 Ma): The North Panthalassic Oscillation  

Science.gov (United States)

An Arctic Oscillation-type variability is found and investigated in two multi-millennia fully coupled climate simulations of the Permian/Triassic (251Ma) period using the Community Climate System Model, Version 3 (CCSM3). We refer to this mode of variability as the North Panthalassic Oscillation (NPO) and diagnose its character in both Permian experiments. The first simulation is a realistic representation of the Permian/Triassic boundary where CO2 levels are set to 10 times present day values. The NPO in this experiment manifests in the western Panthalassic Ocean (akin to the Pacific Ocean). The second simulation represents a much colder Permian world where CO2 levels are set to present day values. In this experiment, the NPO demonstrates its ability to change its maximum variance location from eastern Panthalassa (akin to the Atlantic Ocean) to western Panthalassa, by the end of the simulation. The NPO's ability to flip dominance location is influenced by sea ice expansion into eastern Panthalassa and subsequent changes in baroclinicity and storm tracks. Tropical precipitation is also shown to play a smaller role in the cold case where the mid-latitude connection to the tropics is stronger.

Shields, C. A.; Kiehl, J. T.

2007-12-01

280

Overview of the central North American basins and their relation to deep curstal structure  

Energy Technology Data Exchange (ETDEWEB)

As our knowledge of deep structure of major central North American basins has increased, it has become clear that they have experienced long and complicated tectonic histories. A knowledge of these histories is especially important to efforts to formulate exploration strategies for deeper horizons and frontier areas. Regional geophysical and geologic studies of these basins indicate that Precambrian features have often exerted considerable control on basinal development (e.g., Anadarko basin, Rome trough, Rough Creek graben, Pedregosa basin). A particularly important tectonic event was the Eocambrian continental breakup which extensively rifted the southern margin of North America. Although this rifting event is manifested in various ways, its extent can be estimated by mapping he deep-seated crustal anomalies which probably formed at this time. Although age relations are uncertain in most cases, deep-seated anomalies are associated with the Arkoma basin, Anadarko basin, Illinois basin, Mississippi embayment, and Permian basin. There are many similarities in the development of these basins, but they all can be shown to have unique tectonic histories.

Keller, G.R.; Denison, R.E.

1984-04-01

 
 
 
 
281

Report of laboratory testing on rock core samples - Detten No. 1 (PD-6) well, Palo Duro Basin, Texas: unanalyzed data  

International Nuclear Information System (INIS)

This report contains laboratory test results for rock samples from Detten No. 1 Well of the Permian Basin. Laboratory test samples were measured for water content, density and effective porosity, Schmidt rebound hardness index, splitting tensile strength, slake durability index and Atterberg limits. Specimen descriptions listed in Appendix 1 include the depth to the top of the specimen, the formation and lithological description for each specimen. These data are preliminary. They have been neither analyzed nor evaluated

1984-01-01

282

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

283

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 assem...

Modie B N; Le Hérissé A

2009-01-01

284

First report of the fertile plant genus Umkomasia from Late Permian beds in India and its biostratigraphic significance  

Energy Technology Data Exchange (ETDEWEB)

The genus Umkomasia Thomas, a female fructification of Dicroidium, is reported from Late Permian beds exposed in the Behra Rivulet near the village of Karaonda in the Tatapani-Ramkola Coalfield, Chhattisgarh, India. This is the first record of this genus from the Late Permian, and from Indian Gondwana. Two species have been recognized: Umkomasia polycarpa Holmes and U. uniramia Axsmith, Taylor, Taylor and Cuneo. The find suggests that the genus Dicroidium appeared in the Late Permian before reaching its acme in the Middle-Upper Triassic.

Chandra, S.; Singh, K.J.; Jha, N. [Birbal Sahni Institute for Paleobotany, Lucknow (India)

2008-07-15

285

Paleomagnetism of Late Permian volcanic rocks from South Transbaikalia: preliminary results  

Science.gov (United States)

Tamir volcano-tectonic structure (VTS) is one of the largest Late Paleozoic rift related features within Selengin-Vitim volcano-plutonic belt. The belt was formed in the back area of Siberian continent active margin (Gordienko et al., 2010). Igneous-sedimentary rocks within Tamir VTS are presented by contrastive volcanites more than 5 km thick. The deposits are subdivided into three suits: Ungurkuy (mostly basaltic), Tamir (acidic volcanics and tuffs) and Chernoyar (presented mostly by basalts, andesites and tuffs, sandstones and conglomerates). The age of youngest suits (Tamir and Chernoyar) is Late Permian, Middle-late Triassic accordingly. The age of Ungurkuy suit is deemed to be between Late Carboniferous and Late Permian (Gordienko et al., 1998; Popeko et al., 2005). Volcanic deposits of the three suits were studied to create APWP for the Siberian craton. 200 oriented samples from 31 sites were collected from the Tamir, Shazaga, Kiret, Ungurkuy and Ara-Kiret river valleys within South Transbaikalia. A number of samples were characterized by interpretable paleomagnetic signal. Tamir and Chernoyar rocks were collected from monoclinal structure within Tamir river valley. 5 sites show direction of magnetization similar to directions revealed from Early Cretaceous volcanites from nearby area (Metelkin et al., 2004). The magnetization is metachronous. In the other 8 sites the directions of magnetization are bipolar. The magnetization direction is well-correlated with Triassic APWP of Europe (Torsvik, Cocks, 2005). The volcanites of Ungurkuy suite show mostly monopolar (normal polarity) magnetization direction (formed before crustal folding) between Early Permian and Permian-Triassic Siberian poles, which indicates its Late Permian age. The normal polarity of the deposits indicates its formation in the period between Kiama superchron, characterized by reversal polarity, and Illavara hyperchron with mixed polarity - 265 Ma. This work was supported by the Russian Foundation for Basic Research, project no. 13-05-12030.

Fedyukin, I.; Shatsillo, A.

2013-12-01

286

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

287

World class Devonian potential seen in eastern Madre de Dios basin  

Energy Technology Data Exchange (ETDEWEB)

The Madre de Dios basin in northern Bolivia contains thick, laterally extensive, organic-rich Upper Devonian source rocks that reached the oil-generative stage of thermal maturity after trap and seal formation. Despite these facts, less than one dozen exploration wells have been drilled in the Madre de Dios basin, and no significant reserves have been discovered. Mobil geoscientists conducted a regional geological, geophysical, and geochemical study of the Madre de Dios basin. The work reported here was designed to assess the distribution, richness, depositional environment, and thermal maturity of Devonian source rocks. It is supported by data from over 3,000 m of continuous slimhole core in two of the five Mobil wells in the basin. Source potential also exists in Cretaceous, Mississippian, and Permian intervals. The results of this study have important implications for future exploration in Bolivia and Peru.

Peters, K.E.; Wagner, J.B. [Mobil Technology Co., Dallas, TX (United States); Carpenter, D.G. [Mobil New Business Development, Americas, Dallas, TX (United States); Conrad, K.T. [Mobil Exploration Norway, Stavanger (Norway)

1997-02-17

288

Thermal history, hydrocarbon generation and migration in the Horn Graben in the Danish North Sea: a 2D basin modelling study  

Science.gov (United States)

In this study a 2D basin model has been built along a transect crossing the Horn Graben in WNW-ESE direction. The aim of the investigation was to improve the understanding of the thermal evolution of the basin and its influence on possible petroleum systems. The 2D model of the subsurface is based on one seismic line and data from two exploration wells. Both wells TD’ed in Triassic sediments. The updoming of the Ringkøbing-Fyn High began during Late Carboniferous Early Permian. At the end of the Permian the Horn Graben became active due to regional extension. The subsequent sedimentation history from Triassic to date is well recorded by well reports. A matter of debate has been whether or not significant amounts of Pre-Permian sediments exist in this area of the North Sea. Since organic material rich Paleozoic sediments serve as source rocks in widespread areas of North Germany and the southern North Sea it would be of great importance to know whether the same deposits exist in the Horn Graben. Nielsen et al. (Bull Geol Soc Denmark Copenhagen 45:1 10, 1998) introduced a model, which shows Paleozoic sediments covering the basement at a maximum depth of 6.5 km. Assuming, Paleozoic sediments are underlying the Permian salt deposits there should be an active petroleum system present. The 2D model includes the Paleozoic source rock and tries to explain why two exploration wells have not found petroleum.

Beha, Andreas; Thomsen, Rene O.; Littke, Ralf

2008-09-01

289

Faulting in the northern Palo Duro Basin, Texas: Revision 1, Topical report  

Energy Technology Data Exchange (ETDEWEB)

Location, vertical displacement, and latest detectable movement have been determined for 90 faults identified in the northern Palo Duro Basin of Texas. The interpretations are based on lithostratigraphic correlations, using geophysical logs and sample logs from 905 wells across 12 counties, and seismic surveys conducted in portions of six counties. The stratigraphic interval studied extends from crystalline basement (Precambrian) to the Alibates Formation (Upper Permian). Most of the faults strike northwest, have near vertical dips, and are associated with the Amarillo Uplift, Oldham Nose, and/or the saddle separating them. Horizontal displacements were not determined. The maximum vertical displacement observed is nearly 6300 ft (1920 m), with maximum offsets on individual faults commonly in the 1000-to 3000-ft (300-to 910-m) range. About half of the faults extend onto the Lower Permian section, and at least 12 of those offset the Alibates Formation. 62 refs., 27 figs., 2 tabs.

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

1986-08-01

290

A transport-limited process model to simulate deposition of the Late Permian succession in Devon, UK  

Science.gov (United States)

The primary environmental controls upon sediment deposition include: climate and its link to sea-level; drainage basin area and surface geology; basement structure and tectonic activity. The interplay of these controls dictates the conditions affecting surface sediment modification and hence the physical facies of a sedimentary deposit. Therefore grain texture, porosity and permeability are a reflection of these conditions of deposition, and together with lateral continuity, are the features that characterise the hydraulic properties of a subsurface sedimentary body. If the conditions are understood, a simulation of the depositional process may offer considerable quantitative insight into the likely 3-D facies, and thus hydraulic, architecture of the late Permian succession in Devon, UK. The sensitivity of the physical processes of sediment deposition to various environmental controls is a long and ill-clarified debate amongst the sedimentological community. In attempts to rank sensitivity to these controls for disparate global case studies, many commentators cite the role played by chaotic amplification of small environmental perturbations. This may explain, for example, the occurrence of ‘random channel avulsions’ in the alluvial rock record. Similarly, very simplified, constant-input constrained applications of process sedimentation models somewhat counter intuitively demonstrate autocyclicity, but also variation between sedimentary cycles. A simple process sedimentation model has been developed to simulate sediment accumulation as a result of significant storm events. Time- and space-discrete storm units travel stochastically down-slope and redistribute sediments according to the local 2-D flow conditions. Confluence of flow units, and outer and inner meander bend erosion and deposition, simulate important 3-D flow features. Deposition occurs in order of decreasing grain size, and lays one of three bedforms depending on the criticality of the flow regime. Future testing of the response of the model to changes in its environment should provide a greater insight into the sensitivity of clastic sedimentary facies to natural controls.

Bunch, M.; Mackay, R.; Tellam, J.; Turner, P.

2003-04-01

291

Euxinia prior to end-Permian main extinction at Xiaojiaba section, Sichuan Province, South China  

Science.gov (United States)

Redox conditions in the global ocean prior to, during, and following the end-Permian mass extinction at 252.28 Ma remain contentious. Previous studies in western Australia, South China, and East Greenland have shown that photic-zone euxinia was present at least intermittently from the early Changhsingian through the Dienerian1-3. Here we report a study of organic carbon isotopes, pyrite sulfur isotopes, TOC, pyritic sulfur content, REE, and major and trace elements from the Upper Permian Xiaojiaba section in the Chaotian district of Guangyuan City, Sichuan Province, China. During the Permian-Triassic transition, this section was located on the northwestern margin of the South China Block, facing the Paleo-Tethys Ocean. Our results indicate that suboxic conditions prevailed during the Wuchiapingian and suboxic to anoxic conditions with several pulses of euxinia during the Changhsingian. ?13Corg values are mostly -28‰ to -26‰ but show three positive excursions (to -22‰) prior to the end-Permian mass extinction horizon. These positive excursions are associated with higher Spy concentrations (to ~1%). ?34Spy values are variable (from -41‰ to +5‰) but show a sharp negative excursion in the late Changhsingian (to -43.4‰) that coincided with the most positive ?13Corg values. This horizon is also associated with increases in Eu/Eu*, Baxs, ?REE, Si, and redox-sensitive metals such as V. These patterns reflect linkage of the C and S cycles during the latest Permian, possibly in response to redox controls. The observed positive excursions in ?13Corg may be due to organic inputs from green sulfur bacteria, which exhibit a smaller photosynthetic fractionation (-12.5‰4) than eukaryotic algae. The pronounced negative excursion of ?34Spy corresponds to a sulfate-sulfide S isotope fractionation of about -60‰, suggesting a large flux of syngenetic framboidal pyrite, which would be indicative of euxinic water-column conditions. We infer that the euxinia prior to the main extinction horizon may have been caused by oceanic oxygen-minimum zone expansion and upward movement of the chemocline5. The coupled increases in Eu/Eu* and Baxs may record hydrothermal influence, possibly accompanied by increased ocean acidity and high seawater temperatures. Collectively, our results document major changes in seawater chemistry during the Changhsingian prior to the main end-Permian crisis.

Wei, H.; Algeo, T. J.; Chen, D.; Yu, H.

2013-12-01

292

37 - Roe Basin  

...Hills35 - Magilligan Lowlands36 - Binevenagh37 - Roe BasinRoe Basin LandscapeRoe Basin Geodiversity...Digital DatasetsStrategic Environmental Assessment (SEA)37 - Roe BasinLast updated: 9 February 2007This...

293

Mesozoic evolution of the Amu Darya basin  

Science.gov (United States)

This study, granted by the Darius Programme, aims at proposing a model of tectono-stratigraphic evolution of the Amu Darya basin since the Late Palaeozoic and to understand the relationship with the nearby basins. The Amu Darya basin, as its close eastern neighbour, the Afghan-Tajik basin, lies on the Turan platform, after the closure of the Turkestan Ocean during the Late Paleozoic. These two basins, spread on mainly lowlands of Turkmenistan, southwest Uzbekistan, Tajikistan, and northern Afghanistan, are separated from one another by the South-Western Gissar meganticline, where series of the northern Amu Darya margin are outcropping. The evolution is closely controlled by several periods of crustal thinning (post-collision rifting and back-arc extension), with some marine incursions, coming in between accretions of continental blocks and collisions that succeeded from the Late Triassic-Early Jurassic (Eo-Cimmerian orogeny) to the Cenozoic times. These orogenies controlled the deposition of thick clastics sequences, and the collision of the Indian Plate with Eurasia strongly deformed the sedimentary cover of the Afghan-Tajik basin. The more than 7 km thick Meso-Cenozoic sedimentary succession of the Amu Darya basin, lies on a complex system of rifts and blocks. Their orientation and age (late Permian, Triassic?) are not well known because of deep burial. The north-eastern margin, with the Bukhara (upper margin) and Chardzhou steps, is NW oriented, parallel to the Paleozoic Turkestan suture. The orientation bends to W-E, in the part of the Gissar situated to the North of the Afghan-Tajik basin. This EW trending orientation prevails also in the south(-eastern) margin of the basin (series of North Afghanistan highs) and in the Murgab depression, the south-eastern deepest portion of the Amu Darya basin. It is in this area and in the eastern part of the Amu Darya basin that the Jurassic as well as the lower Cretaceous sediments are the thickest. The south-western part of the basin is occupied by the Pre-Kopet Dagh Cenozoic foreland basin NW oriented, possibly underlain by an earlier extensional trough. The main elements of the sedimentary pile, which can be partly observed in the South-Western Gissar are: Lower to Middle Jurassic continental to paralic clastic rocks; upper Middle to Upper Jurassic marine carbonate then thick Tithonian evaporite rocks, sealing the reservoirs in the Jurassic carbonates; continental Neocomian clastic rocks and red beds, Aptian to Paleogene marine carbonate and clastic rocks. To reconstruct the geodynamic evolution of the Amu Darya Basin, we analysed the subsidence by backstripping of some wells/pseudo-wells and of three cross-sections with some examples of thermal modelling on the periods of maturation of the potential source rocks. The crustal thinning events take place in the Permo-Triassic? (depending on the age of the rifts underlying the basin), in Early-Middle Jurassic and during the Early Cretaceous, resulting in increases of the tectonic subsidence rates.

Brunet, Marie-Françoise; Ershov, Andrey; Korotaev, Maxim; Mordvintsev, Dmitriy; Barrier, Eric; Sidorova, Irina

2014-05-01

294

09 river basin planning  

...coordinated planning system based within river basins. iMPort AncE oF riVEr BASin PLAnninG River basin planning is an ongoing...the sea at a single river mouth, estuary or delta. r iver Basin d istrict...iver Basin d istrict: A river basin or several small river basins combined with larger river basins or joined with neighbouring...

295

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

296

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

International Nuclear Information System (INIS)

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

297

U-Th-Geochemistry of Permian and Triassic sediments of the Drauzug, Carinthia, Austria  

International Nuclear Information System (INIS)

Chemical analysis of samples of Triassic and Permian rocks from the Drauzug, Carinthia and Austria was carried out. U concentration was measured by flurimetry, Th and Cu by spectrophotometry using Thoronol method or Arsenazo III method for Th, Fe by titrimetry and V, Ba, Sr by atomic absorption spectrophotometry. The average U concentration ranged from 0.8 to 4.6 ppm and the Th concentration from 3.2 to 15.6 ppm depending upon the mineral material. The quartzporphyries contained the highest concentration of both. It was concluded that the Permian-Triassic series are very similar to the equivalent deposits in Northern Italy. Assuming a lateral displacement, the former represent the Northern marginal part of the latter and therefore are inferior in thickness and thus not favourable for larger U mineralization

1976-01-01

298

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

299

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

International Nuclear Information System (INIS)

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. (Auth.)

1981-01-01

300

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)

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 environment

2000-01-01

 
 
 
 
301

Ocean Acidification and the End-Permian Mass Extinction: To What Extent does Evidence Support Hypothesis?  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Ocean acidification in modern oceans is linked to rapid increase in atmospheric CO2, raising concern about marine diversity, food security and ecosystem services. Proxy evidence for acidification during past crises may help predict future change, but three issues limit confidence of comparisons between modern and ancient ocean acidification, illustrated from the end-Permian extinction, 252 million years ago: (1) problems with evidence for ocean acidification preserved in sedimentary rocks, wh...

Stephen Kershaw; Sylvie Crasquin; Yue Li; Pierre-Yves Collin; Marie-Béatrice Forel

2012-01-01

302

Brachiopods, fusulines and palynomorphs of the Mengkarang Formation (Early Permian, Sumatra) and their palaeobiogeographical significance  

Science.gov (United States)

Brachiopods, fusulines and palynomorphs from the Lower Permian Mengkarang Formation (Sumatra, Indonesia) have been studied in order to establish the palaeogeographical position and the palaeolatitude of the West Sumatra Block. The position of the West Sumatra Block within the Palaeo-Tethys and Panthalassa oceans and its relationships to their marginal landmasses, in particular the Gondwana supercontinent and the Cathaysian palaeogeographical area, currently is uncertain.

Crippa, G.; Angiolini, L.; Van Waveren, I.; Crow, M. J.; Hasibuan, F.; Stephenson, M. H.; Ueno, K.

2014-01-01

303

Paleoecology of flora from coal measures of Upper Permian in western Guizhou  

Energy Technology Data Exchange (ETDEWEB)

Based on paleobotany, palynology and sedimentology, the paper discusses the paleoecology of flora from coal measures of Upper Permian in Western Guizhou. The four major floras are: the swamp flora dominated by Lycopodiales, the water front floras dominated by Calamites, the floodplain flora dominated by Gigantopterides, Psaronics and the upland flora dominated by conifers, Ginkgos and Pteridospermus. The features of the different floras are described in detail. 6 refs., 3 figs.

Guo, Y. (China University of Mining and Technology (China))

1990-03-01

304

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)

1998-05-13

305

Reproductive biology of the Permian Glossopteridales and their suggested relationship to flowering plants.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The discovery of permineralized glossopterid reproduction organs from Late Permian deposits in the Beard-more Glacier region (central Transantarctic Mountains) of Antarctica provides anatomical evidence for the adaxial attachment of the seeds to the megaasporophyll in this important group of Late Paleozoic seed plants. The position of the seeds is in direct contradiction to many earlier descriptions, based predominatly on impression/compression remains. The attachement of the ovules on the ad...

1992-01-01

306

A first Late Permian fish fauna from Baghuk Mountain (Neo-Tethyan shelf, central Iran)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A diverse Late Permian assemblage of chondrichthyan and actinopterygian micro- and macroremains is presented from the central Iranian locality of Baghuk Mountain for the first time. The vertebrate remains were found in sediments containing mainly pelagic organisms such as nautiloids, ammonoids, and conodonts. Their habitat is interpreted as a deep shelf area with well-oxygenated bottom water conditions below the storm wave base. The chondrichthyans are represented by various dermal denticles,...

Hampe O; Hairapetian V; Dorka M; Witzmann F; Akbari A M; Korn D

2012-01-01

307

Size-Frequency Distributions along a Latitudinal Gradient in Middle Permian Fusulinoideans  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 al...

2012-01-01

308

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

309

Organic geochemistry across the Permian-Triassic transition at the Idrijca Valley, Western Slovenia  

International Nuclear Information System (INIS)

Bulk and molecular stable C isotopic compositions and biomarker distributions provide evidence for a diverse community of algal and bacterial organisms in the sedimentary organic matter of a carbonate section throughout the Permian-Triassic (P/Tr) transition at the Idrijca Valley, Western Slovenia. The input of algae and bacteria in all the Upper Permian and Lower Scythian samples is represented by the predominance of C15-C22 n-alkanes, odd C-number alkylcyclohexanes, C27 steranes and substantial contents of C21-C30 acyclic isoprenoids. The occurrence of odd long-chain n-alkanes (C22-C30) and C29 steranes in all the samples indicate a contribution of continental material. The decrease of Corg and Ccarb contents, increase of Rock-Eval oxygen indices, and 13C-enrichment of the kerogen suggest a decrease in anoxia of the uppermost Permian bottom water. The predominance of odd C-number alkylcycloalkanes, C27 steranes, and C17 n-alkanes with ?13C values ?-30%o, and 13C-enrichment of the kerogens in the lowermost Scythian samples are evidence of greater algal productivity. This increased productivity was probably sustained by a high nutrient availability and changes of dissolved CO2 speciation associated to the earliest Triassic transgression. A decrease of Corg content in the uppermost Scythian samples, associated to a 13C-depletetion in the carbonates (up to 4%o) and individual n-alkanes (up to 3.4%o) compared to the Upper Permian samples, indicate lowering of the primary productivity (algae, cyanobacteria) and/or higher degradation of the organic matter

2004-01-01

310

Sulfur isotopic evidence for chemocline upward excursions during the end-Permian mass extinction  

Science.gov (United States)

The latest Permian was a time of major change in ocean chemistry, accompanying the greatest mass extinction of the Phanerozoic. To examine the nature of these changes, samples from two well-studied marine sections that span the Permian-Triassic boundary have been analyzed: the Meishan and Shangsi sections located in Southern China. Isotopic analysis of the carbonate-associated sulfate in these samples provides a detailed record of several isotopic shifts in ? 34S CAS approaching and across the PTB, ranging from +30 to -15‰ (VCDT), with repeated asynchronous fluctuations at the two locations. We interpret the patterns of isotopic shifts, in conjunction with other data, to indicate a shallow unstable chemocline overlying euxinic deep-water which periodically upwelled into the photic zone. These chemocline upward excursion events introduced sulfide to the photic zone stimulating a bloom of phototrophic sulfur oxidizing bacteria. We hypothesize that elemental sulfur globules produced by these organisms and 34S-depleted pyrite produced in the euxinic water column were deposited in the sediment; later oxidation led to incorporation as CAS. This created the large changes to the ? 34S CAS observed in the latest Permian at these locations.

Riccardi, Anthony L.; Arthur, Michael A.; Kump, Lee R.

2006-12-01

311

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

2009-06-01

312

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

313

Exploratory shaft conceptual design report: Paradox Basin  

International Nuclear Information System (INIS)

This conceptual design report summarizes the conceptualized design for an exploratory shaft facility at a representative site in the Paradox Basin located in the southeastern part of Utah. Conceptualized designs for other possible locations (Permian Basin in Texas and Gulf Interior Region salt domes in Louisiana and Mississippi) are summarized in separate reports. The purpose of the exploratory shaft facility is to provide access to the reference repository horizon to permit in situ testing of the salt. The in-situ testing is necessary to verify repository salt design parameters, evaluate isotropy and homogeneity of the salt, and provide a demonstration of the constructability and confirmation of the design to gain access to the repository. The fundamental purpose of this conceptual design report is to assure the feasibility of the exploratory shaft project and to develop a reliable cost estimate and realistic schedule. Because a site has not been selected and site-specific subsurface data are not available, it has been necessary to make certain assumptions in order to develop a conceptual design for an exploratory shaft facility in salt. As more definitive information becomes available to support the design process, adjustments in the projected schedule and estimated costs will be required

1983-01-01

314

Illawarra Reversal: the onset of the end-Permian mass extinction  

Science.gov (United States)

The Permian magnetostratigraphic records demonstrate that a remarkable change occurred in geomagnetism in the Late Guadalupian (Middle Permian; ca. 265 Ma) from the long-term stable Kiaman Reverse Superchron (throughout the Late Carboniferous and Early-Middle Permian) to the Permian-Triassic Mixed Superchron with frequent polarity change (in the Late Permian and Triassic). This unique episode called the Illawarra Reversal probably reflects a significant mode change in geodynamo in the outer core of the planet after a 50 million year-long stable geomagnetism. The Illawarra Reversal was likely led by the appearance of thermal instability at the 2,900 km-deep core-mantle boundary in connection with mantle superplume activity. The Illawarra Reversal and the Guadalupian-Lopingian boundary event recorded the significant transition from the Paleozoic to Mesozoic-Modern world. Major global environmental changes in the Phanerozoic occurred almost simultaneously in the latest Guadalupian, e.g., 1) mass extinction, 2) ocean redox change, 3) sharp isotopic excursions (C and Sr), 4) sea-level drop, and 5) plume-related volcanism. In addition to the claimed possible link between the above-listed various environmental changes and mantle superplume activity, here I propose an extra explanation that a change in the core's geodynamo may have played another important role in determining the surface climate of the planet and the course of biotic evolution. When a superplume is launched from the core-mantle boundary, resultant thermal instability makes the geodynamo's dipole of the outer core unstable, and lowers the geomagnetic intensity. Being modulated by geo- and heliomagnetism, cosmic ray flux from the outer space into the Earth's atmosphere changes along time. The more cosmic ray penetrates through the atmosphere, the more cloud develops to increase albedo, thus enhances cooling the Earth's surface. The Illawarra Reversal, the Kamura cooling event, and other unique geologic phenomena in the Late Guadalupian were all likely caused by the superplume activity that initially triggered the breakup of Pangea. The secular change of cosmic radiation may explain not only the extinction-related global climatic changes in the end-Guadalupian but also the long- term global warming/cooling trend in Earth"fs history in terms of cloud coverage over the planet.

Isozaki, Y.

2008-12-01

315

Laboratory index testing on rock core samples from G. Friemel No. 1 (PD-5) well, Palo Duro Basin, Texas: unanalyzed data  

International Nuclear Information System (INIS)

This report contains water content, density, effective porosity, Schmidt rebound hardness index, splitting tensile strength, Slake durability index, and Atterberg limits determination for rock samples from the G. Friemel No. 1 Well in the Permian Basin. Descriptions of specimens tested including depth, formation and lithology are included in Appendix 1. These data are preliminary. They have not been analyzed or evaluated. 4 references, 4 tables

1984-01-01

316

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

317

Exploration and hydrocarbon potential of interior basins, Alaska  

Energy Technology Data Exchange (ETDEWEB)

During the early 1980s, ARCO Alaska, Inc., conducted an extensive hydrocarbon exploration program in the Alaskan Interior. The study focused on several basinal areas: Middle Tanana, Minchumina, Holitna, Yukon Flats, and Kandik. Other basinal areas (Upper Tanana, Lowre Tanana, and Yukon-Koyukuk) have been reported in the literature to have lower hydrocarbon potential and were not as extensively studied. Several geological and geophysical techniques, including gravity, aeromagnetic, and CDP seismic surveys, were used to establish sediment thickness, basin volume, morphology, and structural style. Analytical data were collected for hydrocarbon source, reservoir potential, and thermal history. Specialized structural and biostratigraphic studies were conducted in some areas. The Middle Tanana and Kandik basins have the highest hydrocarbon potential. A 6-mi wide by 26-mi long half-graben within the Middle Tanana basin contains 20,000 ft of section. The 1984 ARCO Totek Hills 1 well penetrated 3,015 ft of Tertiary (Pliocene to Eocene) section unconformably overlying metamorphic basement. Because it was drilled on the basin flank, the well tested only the uppermost section within the half-graben. Sandstones averaged 17% porosity and 11 md permeability. Claystones containing type II kerogen showed good oil-generating potential (pyrolysis S1 + S2 values average 17 mg/g). The Kandik basin contains excellent source rocks in the Triassic Glen Shale (S2 averaging 16 mg/g). Hydrocarbon thermal maturation changes from immature to postmature in a stepwise fashion across thrust faults from southeast to northwest. Solid residue of migrated hydrocarbons occurs in formations of Devonian, Pennsylvanian, Permian, and Triasic age.

Grether, W.J.; Morgan, K.A.

1988-01-01

318

Generation and hydrocarbon entrapment within Gondwanan sediments of the Mandapeta area, Krishna-Godavari Basin, India  

Energy Technology Data Exchange (ETDEWEB)

The discovery of hydrocarbons (mainly gas) in commercial quantities from Gondwanan sediments in the Mandapeta field of Krishna-Godavari Basin, India, provided impetus for intensified exploration in Mandapeta and the adjoining Kommugudem, Draksharama and Endamuru fields. Both oil and gas have been found in the reservoirs of Mandapeta (Triassic) and Golapalli (Early Cretaceous) formations. Mature, localised, basal shales (1.0-1.1% Ro) in the Mandapeta formation have sourced the oils from the Mandapeta Sandstone reservoir (Triassic). The oils being produced from Golapalli Sandstone reservoir (Early Cretaceous) are relatively less mature and have been sourced by the underlying shales in the Mandapeta Formation at a maturity level of 0.80-0.85% Ro. The source and maturity data preclude liquid hydrocarbon sourcing from the Kommugudem (Permian) sequence. Permian coals and shales of the Kommugudem Formation are the major source rocks for gaseous hydrocarbons in this area. The hydrocarbon generation started in Early Cretaceous in the Kommugudem Formation, but the intermittent tectonic activity (with associated structural developments) has resulted in reorientation and redistribution of the then existing trap configurations. The present day maturity level of the Permian sediments in the Mandapeta field is 1.2% Ro or greater, capable of generating gas dominantly. The Raghavapuram shale in the Mandapeta area is adequately mature and has good hydrocarbon potential for oil generation. The probability of finding hydrocarbon reserves in the sands of Raghavapuram shales and other suitable traps is high. Modern seismic information together with geologic models can give new exploration leads. (Author)

Raza Khan, M.S.; Sharma, A.K.; Sahota, S.K.; Mathur, M. [RCL, ERBC, ONGC, Assam (India)

2000-07-01

319

Petroleum geology of the Puguang sour gas field in the Sichuan Basin, SW China  

Energy Technology Data Exchange (ETDEWEB)

The Puguang sour gas field in northeastern Sichuan Basin is the largest gas discovery in the Paleozoic marine strata in China, with at least 9 trillion cubic feet (tcf) of proven gas reserves. It is one of the many anticlinal structures formed during the Indo-Sinian orogeny, with gas being trapped in a composite structure-lithology pool. The presence of the Upper Permian coal measures, Lower Silurian and Lower Cambrian marine shales provided excellent hydrocarbon source rocks. The Lower Triassic and Upper Permian oolitic dolomites serve as high quality reservoir rocks, with 10-25% porosity and 1-1000 mD permeability, largely due to diagenetically produced secondary porosity. The Lower and Middle Triassic evaporate beds have acted as the direct top seal for the large Lower Triassic-Upper Permian gas accumulation. The thick Upper Triassic and Jurassic mudstone beds regionally cap the underlying marine carbonate strata. The deep-seated basement faults acted as vertical hydrocarbon migration conduits during faulting, and became effective flow barriers when the faulting ceased. The deep burial of a paleo-oil accumulation in reservoirs rich in sulfate resulted in extensive thermochemical sulfate reduction (TSR). This, together with the new gas injection and structural reconfiguration, transformed a paleo-oil pool to a large sour gas pool. (author)

Ma, Yongsheng; Guo, Tonglou; Zhu, Guangyou; Cai, Xunyu [SINOPEC Southern Exploration and Development Company, Kunming, Yunnan 650200 (China); Zhang, Shuichang [PetroChina Research Institute of Petroleum Exploration and Development, Beijing 100083 (China); Li, Maowen [Geological Survey of (Canada)

2008-04-15

320

Geohydrology surrounding a potential high level nuclear waste repository in the Palo Duro Basin, Texas  

International Nuclear Information System (INIS)

The Palo Duro Basin of the Texas Panhandle is being investigated as a potential high level nuclear waste repository site. As groundwater is the most likely mechanism for radionuclide movement, it is desirable to locate a repository in a hydrologic regime which is favorable for waste isolation and containment. The Palo Duro Basin consists of deep brine aquifers of low regional permeability underlying a thick Permian age evaporite section. The overlying Permian age evaporites are the Dockum and Ogallala fresh water aquifiers. Observed potentiometric data in the principal aquifers indicate a potential for downward flow from the surficial aquifiers to the deep brine aquifers. Groundwater movement in these deep aquifers is very slow. Modeling efforts indicate flow times of hundreds of thousands to over a million years for groundwater to reach the basin margins. Investigative methods have included drill-stem testing similar to oil field methodology, modified drill-stem testing with tools developed for low-permeability formations and long term production tests similar to conventional water well pumping tests. Testing has generally indicated permeability of .1-10 millidarcies in the water transmitting units

1984-03-26

 
 
 
 
321

Dissolution of evaporites in and around the Delaware Basin, southeastern New Mexico and west Texas  

International Nuclear Information System (INIS)

permian evaporites in the Ochoan Castile, Salado, and Rustler Formations in the Delaware Basin of southeast New Mexico and west Texas have been subjected to various degrees of dissolution (notably of halite and gypsum) through geologic time. Eastward tilting of the Delaware Basin has resulted in the exhumation and erosion of Ochoan rocks in the western part of the basin. Waters in the Capitan, Rustler, Castile, and Bell Canyon Formations have previously been proposed as agents or consequences of evaporite dissolution according to four principal models: solution-and-fill, phreatic dissolution, brine density flow, and stratabound dissolutin (along bedding planes). Several geomorphological features of positive and negative relief have previously been cited as indicators of evaporite dissolution. Brine density flow has been used to explain the selective dissolution of certain evaporite horizons during the late Cenozoic. A review of available geological data has revealed that: Halite deposition was probably not so extensive as formerly believed. Waters with potential to dissolve evaporites are in the Rustler and Capitan, but not in the Bell Canyon, Salado mine seeps, or the Castile brine reservoirs. Brine density flow has not been active in removing most of the missing halite, nor are point-source dissolution features likely to have their roots at the Bell Canyon. Major evaporite dissolution has not been confined to the late Cenozoic, but much of it took place during the Permian, Triassic, Jurassic, and Tertiary periods. The Bell Canyon Formation has been a sink for dissolution-derived brine

1983-01-01

322

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

323

Neopaleozoic biostratigraphy of the Parana Basin; Bioestratigrafia do neopaleozoico da Bacia do Parana  

Energy Technology Data Exchange (ETDEWEB)

Surface samples and cores from 31 exploratory wells were chosen as being the most representative among those drilled by PETROBRAS across the Parana Sedimentary Basin, from Mato Grosso and Goias to Rio Grande do Sul. Their analysis yielded a large amount or Saccites, Monoletes and Monocolpates spores, in addition to representatives of Tasmanales. From the great number of identified forms, 40 species - characterized by their wide geographical distribution allied to a short vertical range - were selected and used as a basis for the biostratigraphical subdivision of the Gondwana section of this sedimentary basin. This biostratigraphic column was divided into six main intervals, designated by the letters G to L, some with further subdivisions. The comparison of the species with those described from other regions provided sufficient geochronological data for the dating of the different intervals. It also demonstrated that the Upper Paleozoic sedimentary sequence in the Parana Basin ranges from the Upper Pennsylvanian (Stephanian C) to the Upper Permian (Kazanian). To complete the paleogeologic data the previously established zonation of the Devonian section was also included. The correlation of the biostratigraphic intervals across the basin and their relationship with the rock-stratigraphic units are demonstrated in several sections. The interpretation of these sections and of the biostratigraphic interval isopachous maps provided important information on the paleogeographic development of the basin. Among the more significant results is evidence of the start of the Permo-Carboniferous sedimentation in the northern regional depression, of a subsequent southward tilting of the basin accompanied by the progressive advance of the deposits toward the Rio Grande do Sul shield and of a Lower Permian lacuna in eastern Parana indicating the beginning of the epeirogenic process which culminated with the rise of the Ponta Grossa arch. The paper also presents some paleoecological considerations and the concluding chapter deals with the systematic discussion of the sporomorphs accompanied by illustrations of the described species. (author)

Daemon, Roberto Ferreira; Quadros, Luiz Padilha de

2006-11-15

324

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 SciELO Argentina | Language: Spanish 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 regis [...] trado 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 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 re [...] ported for the first time in Argentina with the new species Borestus lunatus. In addition, Sinuitina (Spirilira) tenuis nov. subgen. nov. sp. ( Bellerophontoidea) is proposed. The new subgenus is characterized by spiral ornamentation, subcordate whorls in section, and a reduced collabral ornamentation on outer flanks and dorsum.

Karina, Pinilla; Nora, Sabattini; Julio, Hlebszevitsch.

325

Pteridophytes from Lower Gondwana formations of the Ib River Coalfield, Orissa and their diversity and distribution in the Permian of India  

Energy Technology Data Exchange (ETDEWEB)

Recent extensive investigations carried out in the Ib River Coalfield, Mahanadi Master Basin, Orissa, identified numerous fossiliferous beds in the lower Gondwana deposits. Six exposures of the Barakar and lower Kamthi formations yielded diverse and abundant plant remains. The flora includes twenty-three genera representing nine groups viz., Lycopodiales, Equisetales, Sphenophyllales, Filicales, Cordaitales, Coniferales, Ginkgoales, Cycadales and Glossopteridales. Systematic descriptions of the pteridophyte taxa namely Cyclodendron (Lycopodiales), Schizoneura, Raniganjia, Bengalia, equisetaceous stems (Equisetales), Trizygia, Benlightfootia (Sphenophyllales), Neomariopteris, and Dichotomopteris (Filicales) are presented in this paper. Pteridophytic leaves comprising nine taxa viz., Cyclodendron leslii, Schizoneura gondwanensis, Raniganjia bengalensis, Bengalia raniganjensis, Trizygia speciosa, Benlightfootia indica, Neomariopteris hughesii, N. talchirensis, and Dichotomopteris sp. together with equisetaceous stems constitute about 7.88% (72 specimens) of the total plant assemblage collected from this coalfield. Among the pteridophytes, equisetaceous stems are most abundant (40.3%; 29 specimens) followed by Schizoneura gondwanensis (20.8%, 15 specimens) and Trizygia speciosa (13.9%, 10 specimens). A summary of the known diversity of pteridophytes in the Indian Permian as a whole is provided.

Goswami, S.; Singh, K.J.; Chandra, S. [Fakir Mohan University, Balasore (India). PG Dept. of Environmental Science

2006-12-15

326

Thermal evolution of inverted basins: Constraints from apatite fission track thermochronology in the Cuyo Basin, Argentine Precordillera  

International Nuclear Information System (INIS)

Apatite fission track thermochronology (AFTT) was applied to derive the thermal history of formation and inversion of the oil-bearing Triassic-Cretaceous Cuyo Basin, Argentine Precordillera. The obtained central fission track ages range from 13 to 163Ma, and the mean track lengths from 8.2 to 13.1?m. Based on the integration of AFTT, stratigraphic and structural data, five evolutionary phases are here proposed for the studied area: I-Late Permian cooling related to the extrusion of basement volcanics, and initial extensional regime responsible for the Cuyo Basin formation, II-Triassic-Jurassic heating linked with the filling, and consequent burial, of the Cuyo Basin, III-Jurassic-Paleogene tectonic stabilization, IV-Early Miocene heating related to the load of foreland sedimentation, V-Late Miocene rapid cooling related to the Cuyo Basin inversion. During the Late Miocene, rock units formed in different crustal levels were juxtaposed through thrust, reverse and normal faulting, resulting in contrasting old and very young central fission track ages in closely spaced samples

2005-12-01

327

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

328

The Permian-Triassic transition: Historical review of the most important ecological crises with special emphasis on the Iberian Peninsula and Western-Central Europe.  

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One of the most important climatic and biological crises of the history of the Earth occurred 250 m.a. ago, during the transition from the Permian to the Triassic. During the Permian, all of the continental blocks were covering one hemisphere forming the Pangea supercontinent, while the other was covered by the Panthalasa ocean. General conditions for living on land were very precarious.

Virgili, Carmina

2008-01-01

329

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

330

North Western River Basin  

...2015North Eastern River BasinNorth Western River BasinRivers and LakesCoastal and...Visits WMUDevelopment ManagementStormwater ManagementNorth Western River BasinManaging our Shared Waters (.PDF 1...

331

Hydrocarbon habitat of San Martin and Cashiriari gas/condensate discoveries, southern Ucayali basin of Peru  

Energy Technology Data Exchange (ETDEWEB)

Fifteen trillion ft/sup 3/ of wet gas in place containing some 800 million bbl of associated liquids have been discovered in the San Martin and Cashiriari anticlines, which are located in the Subandean thrusted foldbelt of the Southern Ucayali basin of Peru. Ultimate recoverable volumes are estimated at 10 trillion ft/sup 3/ of gas and 500 million bbl of liquids including condensate (C5+) and LPG (C3/C4). Most of these potentially recoverable reserves are located in the Cashiriari structure (80% of the gas and 70% of the liquids). They were encountered in fair-excellent sandstone reservoirs of Early Permian and Late Cretaceous age and are thought to be derived from Carboniferous coaly shale source rocks. The Paleozoic (pre-Andean) sedimentary megacycle is represented by deeper shallow marine clastics of Ordovician to Early Carboniferous age (5000 m maximum), including Silurian glaciomarine deposits, overlain by up to 1200 m of Permian-Carboniferous platform carbonates and 600-1000( ) m of Lower Permian-lower Upper Permian coastal-continental clastics. The Mesozoic-Tertiary (Andean) megacycle is represented by a Campanian-Maastrichtian transgressive marine clastic/carbonate and overlying regressive clastic sequence (450 m maximum), followed by several thousand meters of Molasse-type continental infill of the Tertiary foredeep, which was created by the crustal loading in the wake of the compressional Andean orogeny (Peru, Inca, and Quechua phases). Late Tertiary folding and thrusting of the sub-Andean belt was superseded by regional Pleistocene uplift, and parts of the foreland continue to subside.

Mohler, H.P.

1989-03-01

332

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

333

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

International Nuclear Information System (INIS)

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

334

Role of anhydrite diagenesis in the creation of porosity in middle Permian dolostone reservoirs  

Energy Technology Data Exchange (ETDEWEB)

In middle Permian dolostone reservoirs, the most abundant pore type is secondary intercrystalline porosity. Generally ranking second in abundance, but first in many instances, are pores created by dissolution of anhydrite that occurred in the Permian. Much anhydrite was emplaced diagenetically during and following early dolomitization, as nodules, blocky porphyroblasts, and cement, and as combination cement and replacement. Generally, anhydritization was followed by an influx of a low-salinity fluid, which dissolved anhydrite - creating tertiary porosity - or altered it to gypsum, hemihydrate, silica, calcite, or fluorite. Dissolution of anhydrite nodules and porphyroblasts creates distinctive molds with angular and stair-step outlines. Dissolution of anhydrite, which was emplaced as cement and replacement, enhances the original primary and secondary pores by the increment that was replaced. This dissolution also produces voids with angular and stair-step outlines. Replacive anhydrite tends to nucleate within organic-rich components, such as burrows, stromatolites, skeletal grains, ooids, and peloids. Many dolomite crystals have cloudy organic-rich centers, which represent the original replacive crystals, and clear rims of epitaxial dolomite cement. Anhydrite preferentially nucleates within the organic-rich cores, and subsequent dissolution produces hollowed dolomite crystals or intracrystalline porosity. Intracrystalline pores constitute the predominant pore types within many intervals. Anhydrite commonly replaces skeletal grains or ooids, and the replacement of such anhydrite produces a mold that replicates the original shell (biomold). It is possible to determine how many biomolds actually record dissolution of replacive anhydrite. The best Permian reservoirs contain intercrystalline porosity in conjunction with pores created by dissolution of anhydrite and grains.

Jacka, A.D.

1986-03-01

335

Blastoid Body Size - Changes from the Carboniferous to the End-Permian  

Science.gov (United States)

Climate, known for affecting biodiversity within genera of animal species, is often addressed as a major variable of geological systems. The Mississippian subperiod of the Carboniferous was noted for its lush, tropical climate that sustained a variety of biological life. In contrast, the Permian era was marked primarily by an ice age that had started earlier during the Pennsylvanian. The blastoids, a class of the Echinodermata phylum, were in existence from the Silurian (443.4 Ma) to the end of the Permian (252.28 Ma). This study focused on whether climate affected blastoid theca size over the span of those one hundred million years between the Mississippian and the Permian or if was simply a negligible factor. We analyzed size data from the Treatise on Invertebrate Paleontology and correlated it to both Cope's Rule, which states that size increases with geologic time, and Bergmann's Rule, which states that latitude and temperature are catalysts for size change. CO2 levels from known records served as a proxy for global temperature. Our results indicated that the blastoids increased in size by 59% over geologic time. The size of the blastoids increased over geologic time, following Cope's Rule. According to our graphs in R, there was an inverse relationship between volume and climate. Size decreased as temperature increased, which follows Bergmann's Rule. However, we also wanted to observe spatial factors regarding Bergmann's Rule such as paleolatitude and paleolongitude. This info was taken from the Paleobiology Database and showed that a majority of the blastoids were found near the equator, which, according to the other part of Bergmann's Rule, suggests that they would therefore increase in size. Further tests implied strong correlations between temperature, volume, and paleolocation. We ultimately believe that although Cope's Rule is in effect, Bergmann's mechanisms for size may not apply to the blastoids due to the environments that the blastoids lived in or their anatomical compositions.

Nguyen, L.; Tolosa, R.; Heim, N. A.; Payne, J.

2013-12-01

336

Properties of Gondwana coals with emphasis on the Permian coals of Australia and South Africa  

Energy Technology Data Exchange (ETDEWEB)

This review discusses the geological properties of Gondwana coals especially the Permian coals of Australia and South Africa and how the liquefaction, carbonization, combustion and beneficiation of these coals are affected by their properties. Many Gondwana coals have high inertinite and mineral matter contents. Much of the inertinite is often of low reflectance. This low-reflectance inertinite is reactive in carbonization and liquefaction and behaves in a similar manner to vitrinite in this regard. A brief discussion of the resources, location and general information on current uses of these coals is also included. 114 refs., 14 figs., 8 tabs.

Kershaw, J.R.; Taylor, G.H. (CSIRO, Clayton, Vic. (Australia). Division of Materials Science and Technology)

1992-07-01

337

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

1994-12-01

338

Paleomagnetism of Lower Permian Abo and Yeso Formation, Carizzo Arroyo, Lucero Uplift, New Mexico  

Science.gov (United States)

We report paleomagnetic data from Lower Permian hematite-cemented sandstones and siltstones from Carrizo Arroyo, on the eastern edge of the Lucero uplift along the west-side of the middle Rio Grande rift, to test the hypothesis that the rift margins have accommodated extensional strain via vertical axis rotation. In addition, we present a revised interpretation of the structural setting and deformation history of the area, were late-Tertiary transtensional stresses have produced the majority of the structures in the area. The paleomagnetic data are discussed in the context of this hypothesis. In the Rio Grande rift area, a mid-Cenozoic and younger extensional feature defining the eastern margin of the Colorado Plateau, relatively little work has been done to assess the magnitude and sense of vertical axis rotations of fault-bounded crustal blocks within and at the margins of the plateau. A growing body of evidence shows that the Colorado Plateau has experienced some degree of vertical axis rotation and some magnitude of northward translation, although the magnitudes of the rotation and translation have been subject to considerable debate. Eight to ten oriented samples from 50 sites have been fully demagnetized with all sites yielding interpretable results: 41 sites from three sections in the Lower Permian Abo Formation, and 9 sites in the Meseta Blanca Member of the overlying Yeso Formation. In most cases, progressive thermal demagnetization resulted in a nearly univectorial decay of the magnetization to the origin that is well grouped at the site level. After correcting for modest dip of strata, the 50 sites in Carrizo Arroyo yield an estimate group mean (D = 162.1°, I = -4.1°, ?95 = 6.8°, k = 10.18). Overall, the data from this part of the west side of the rift are discordant, in a clockwise since, with Early Permian (about D = 140°, I = -2.0°) and mid-Permian (about D = 145°, I = -4.0°) expected directions. We interpret the paleomagnetic data from Carrizo Arroyo to be consistent with modest clockwise vertical axis rotation of these sections since the latest Paleozoic, arguably during Laramide deformation and subsequent Rio Grande extension. We hypothesize that a component of tectonic rotation has accommodated extensional strain along the margins of the Rio Grande rift since inception. The observed rotation could be the result of oblique-slip displacement of the hanging wall block; in this case, the observed rotation is apparent. Alternatively, the rotation is a true block rotation where the block is decoupled from the underlying strata along a detachment surface. Additional field mapping will help to distinguish between these two possible models.

Petronis, M. S.; Geissman, J. W.

2002-12-01

339

The Tarim picrite-basalt-rhyolite suite, a Permian flood basalt from northwest China with contrasting rhyolites produced by fractional crystallization and anatexis  

Science.gov (United States)

We report major and trace element composition, Sr-Nd isotopic and seismological data for a picrite-basalt-rhyolite suite from the northern Tarim uplift (NTU), northwest China. The samples were recovered from 13 boreholes at depths between 5,166 and 6,333 m. The picritic samples have high MgO (14.5-16.8 wt%, volatiles included) enriched in incompatible element and have high 87Sr/86Sr and low 143Nd/144Nd isotopic ratios ( ?Nd ( t) = -5.3; Sri = 0.707), resembling the Karoo high-Ti picrites. All the basaltic samples are enriched in TiO2 (2.1-3.2 wt%, volatiles free), have high FeOt abundances (11.27-15.75 wt%, volatiles free), are enriched in incompatible elements and have high Sr and low Nd isotopic ratios (Sri = 0.7049-0.7065; ?Nd ( t) = -4.1 to -0.4). High Nb/La ratios (0.91-1.34) of basalts attest that they are mantle-derived magma with negligible crustal contamination. The rhyolite samples can be subdivided into two coeval groups with overlapping U-Pb zircon ages between 291 ± 4 and 272 ± 2 Ma. Group 1 rhyolites are enriched in Nb and Ta, have similar Nb/La, Nb/U, and Sr-Nd isotopic compositions to the associated basalts, implying that they are formed by fractional crystallization of the basalts. Group 2 rhyolites are depleted in Nb and Ta, have low Nb/La ratios, and have very high Sr and low Nd isotopic ratios, implying that crustal materials have been extensively, if not exclusively, involved in their source. The picrite-basalt-rhyolite suite from the NTU, together with Permian volcanic rocks from elsewhere Tarim basin, constitute a Large Igneous Province (LIP) that is characterized by large areal extent, rapid eruption, OIB-type chemical composition, and eruption of high temperature picritic magma. The Early Permian magmatism, which covered an area >300,000 km2, is therefore named the Tarim Flood Basalt.

Tian, Wei; Campbell, Ian H.; Allen, Charlotte M.; Guan, Ping; Pan, Wenqing; Chen, Mimi; Yu, Hongjiao; Zhu, Wenping

2010-09-01

340

Evolution of calc-alkaline to alkaline magmatism through Carboniferous convergence to Permian transcurrent tectonics, western Chinese Tianshan  

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Continuous magmatic activity occurred in the western Chinese Tianshan, Central Asia, from the Carboniferous to the Permian, i.e. before and after the Late Carboniferous amalgamation of Junggar and the Yili Blocks. Zircon U–Pb LA-ICPMS and Ar–Ar data reveal a coincidence in time between regional wrench faulting and granitoid emplacement. Permian post-collisional granitoids crop out within or at the margins of large-scale dextral strike-slip shear zones, some of them show synkinematic fabri...

Wang, Bo; Cluzel, Dominique; Shu, Liangshu S.; Faure, Michel; Charvet, Jacques; Chen, Yan; Meffre, Se?bastien; Jong, Koenraad

2009-01-01

 
 
 
 
341

The thermal and mechanical evolution of the Anadarko basin  

Science.gov (United States)

During the late Mississippian the style of subsidence and sedimentary facies in the Anadarko Basin changed significantly. This marked an interval of rapid subsidence that was unrelated to the pre-existing Cambro-Ordovician trough referred to as the Southern Oklahoma Aulacogen. The sedimentary facies changed from black shales and carbonates to predominantly elastics of the Mississippian-Springer series. At the same time, widespread deposition changed to deposition in a narrow, geographically isolated trough. During a span of close to 23 m.y., extending into the middle Pennsylvanian, nearly 3.5 km of these clastic sediments were deposited in the narrow trough. On the south side of the basin, during the latter half of this time interval, reverse faulting and uplift of the Wichita Mountains accompanied subsidence in the basin. The timing of the uplift indicates that north-south shortening in the basin was not the primary cause of subsidence. This early narrow phase was followed by a return to widespread deposition in late Des Moinesian time, although with continued clastic sedimentation. During the early Permian, elastics graded into evaporites. Subsidence slowed continuously throughout this final widespread phase of subsidence. We model the formation of the Anadarko Basin in terms of elastic flexure of the lithosphere. In order to accommodate the early narrow phase, subsidence is attributed to crustal thinning accompanied by faulting. We show that the final widespread phase of subsidence was accommodated by lithospheric flexure and that the flexural rigidity of the elastic lithosphere increased from D = 4.1·10 30 dyne cm to D = 1.9·10 31 dyne cm during this period. This increase can be attributed to a decrease in heat flow with time. These two phases of subsidence in the Anadarko Basin are consistent with crustal thinning followed by thermal subsidence.

Garner, David L.; Turcotte, Donald L.

1984-08-01

342

77 FR 57188 - Iowa Pacific Holdings, LLC and Permian Basin Railways-Continuance in Control Exemption-Rusk...  

Science.gov (United States)

...Continuance in Control Exemption--Rusk, Palestine & Pacific Railroad, LLC Iowa...2(d)(2) to continue in control of Rusk, Palestine & Pacific Railroad, LLC...miles of railroad (the Line) between Rusk and Palestine, Tex.\\2\\ The Line...

2012-09-17