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1

Permian Basin as a radioactive waste repository  

International Nuclear Information System (INIS)

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

2

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

3

Permian Basin location recommendation report  

International Nuclear Information System (INIS)

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

4

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

5

Injection technology increases oil recovery at Permian Basin  

Energy Technology Data Exchange (ETDEWEB)

This article provided a brief overview of the positive field results of the Powerwave injection technology at an oil field in the Permian Basin. The patented injection technology uses pulses of fluid pressure to create momentary elastic flexure of the pore structure to improve the flow of fluids in sedimentary soils and fractured rock, thereby optimizing the performance of chemical enhanced oil recovery technologies, liquid carbon dioxide injection, water injection, and surfactant/polymer flooding to effectively increase oil recovery. In the example of the West Texas waterflood, the Powerwave technology generated an overall production increase of nearly 50 percent. The significant improvements in production and the increased profitability that resulted from the installation of the Powerwave equipment are expected generate interest in the technology from other operators seeking to maximize oil recovery in their fields. The Edmonton-based company is actively pursuing other contracts in the Permian Basin. 1 fig., 1 ref.

Anon.

2010-09-15

6

Permian `Wolfcamp` limestone reservoirs: Powell ranch field, eastern Midland basin: Discussion  

Energy Technology Data Exchange (ETDEWEB)

The {open_quotes}E&P Notes{close_quotes} paper by S.L. Montgomery (1996) on Wolfcamp resedimented carbonates in the Permian basin concerns an exploration play with the potential for significant reserves; however, its economic importance and geological complexity, and the question of whether his model can be extended to other areas in the Permian basin warrant this discussion.

Mazzullo, S.J. [Wichita State Univ., KS (United States)

1997-10-01

7

Crosswell seismic imaging in the Permian Basin, West Texas, USA  

Energy Technology Data Exchange (ETDEWEB)

Crosswell seismic imaging technology has advanced rapidly over the last three years as the processing methods have become more robust, the cost of data acquisition has fallen, and the interwell distances of operation have increased. The Permian Basin of west Texas, USA is proving to be an ideal environment in which to develop this technology because of the relatively low seismic attenuation of the carbonate-dominated lithology, the moderate well spacings in the large number of mature fields, and the unusually high number of reflecting horizons. Current technology permits us to operate in carbonates at well spacings on the order of 2000 ft (650 m) and to image P- and S-wave reflecting horizons on a scale of 8 to 25 ft (2.4 to 7.6 m). Crosswell technology is not limited to carbonates, although the majority of recent applications have been in this environment. We are involved in three separate crosswell experiments in the Permian Basin, each with unique objectives. The first experiment involves a CO{sub 2} pilot project in a Grayburg Formation reservoir on the eastern edge of the Central Basin Platform. Here we are attempting to characterize the reservoir at a scale unobtainable from 3-D surface seismic data and to image CO{sub 2} fronts directly. The second experiment deals with a waterflood in a Middle Clearfork Formation reservoir on the Eastern Shelf, where we are trying to explain the erratic response of adjacent wells to water injection. In the third project we are trying to image the structure and stratigraphy of subtle {open_quotes}anomalies{close_quotes} in 3-D surface seismic images of the Wolfcamp Formation.

Langan, R.T.; Harris, J.M.; Jensen, T.L. [and others

1995-12-31

8

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

International Nuclear Information System (INIS)

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

9

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1993-05-01

10

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1993-05-01

11

Origin of the Permian-Triassic Iberian Basin, central-eastern Spain  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The Iberian Basin was an intracratonic rift basin in central-eastern Spain developed since Early Permian times. The basin boundary faults were normal, listric faults controlling an asymmetric extension propagating northeast with time. Hercynian or older lineaments controlled the orientation of the Iberian Basin and extension was accommodated basically in the hanging wall block by the formation of secondary grabens and a central high. The basin was related with the coeval Ebro, Cat...

Arche, Alfredo; Lo?pez Go?mez, Jose?

1996-01-01

12

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

13

Permian and Triassic microfloral assemblages from the Blue Nile Basin, central Ethiopia  

Science.gov (United States)

Palynological investigation was carried out on surface samples from up to 400 m thick continental siliciclastic sediments, here referred to as “Fincha Sandstone”, in the Blue Nile Basin, central Ethiopia. One hundred sixty species were identified from 15 productive samples collected along a continuous road-cut exposure. Six informal palynological assemblage zones have been identified. These assemblage zones, in ascending order, are: “Central Ethiopian Permian Assemblage Zone - CEPAZ I”, earliest Permian (Asselian-Sakmarian); “CEPAZ II”, late Early Permian (Artinskian-Kungurian); CEPAZ III - Late Permian (Kazanian-Tatarian); “CETAZ IV”, Lower Triassic (Olenekian Induan); “CETAZ V”, Middle Triassic (Anisian Ladinian); “CETAZ VI”, Late Triassic (Carnian Norian). Tentative age ranges proposed herein are compared with faunally calibrated palynological zones in Gondwana. The overall composition and vertical distribution of miospores throughout the studied section reveals a wide variation both qualitatively and quantitatively. The high frequency of monosaccate pollen in CEPAZ I may reflect a Glossopterid-dominated upland flora in the earliest Permian. The succeeding zone is dominated by straite/taeniate disaccate pollen and polyplicates, suggesting a notable increase in diversity of glossopterids. The decline in the diversity of taeniate disaccate pollen and the concomitant rise in abundance of non-taeniate disaccates in CEPAZ III may suggest the decline in Glossopteris diversity, though no additional evidence is available to equate this change with End-Permian extinction. More diverse and dominant non-taeniate, disaccate, seed fern pollen assignable to FalcisporitesAlisporites in CETAZ IV may represent an earliest Triassic recovery flora. The introduction of new disaccate forms with thick, rigid sacci, such as Staurosaccites and Cuneatisporites, in CETAZ V and VI may indicate the emergence of new gymnospermous plants that might have favourably adapted to coastal plain wetland environments with the return of humid conditions in the Middle to early Late Triassic. The present data constitute the first paleontologically substantiated record for the existence of Permian strata in the Blue Nile Basin. The new results allow for the first time a reliable biostratigraphic subdivision of the central Ethiopia Karoo and its correlation with coeval strata of adjacent regions in Gondwana. From a phytogeographic point of view, the overall microfloral evidence is in support of the position of central Ethiopia occupying the northern part of the southern Gondwana palynofloral province. In view of palaeoecological and paleoclimatic conditions, the microfloral change from the base to the top of the studied section may indicate a response to shifting climatic belts from warm- and cool-temparate climate in the earliest Permian to progressively drier seasonal conditions at successively higher palaeolatitudes during the Late Permian to Middle Triassic.

Dawit, Enkurie L.

2014-11-01

14

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

15

Assessment of potential unconventional Carboniferous-Permian gas resources of the Liaohe Basin eastern uplift, Liaoning Province, China, 2011  

Science.gov (United States)

The U.S. Geological Survey estimated a mean of 448 billion cubic feet of potential technically recoverable unconventional natural gas in Carboniferous and Permian coal-bearing strata in the eastern uplift of the Liaohe Basin, Liaoning Province, China.

Pollastro, Richard M.; Potter, Christopher J.; Schenk, Christopher J.; Charpentier, Ronald R.; Cook, Troy A.; Klett, Timothy R.; Kirschbaum, Mark A.

2012-01-01

16

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

Directory of Open Access Journals (Sweden)

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

Ivan Mlakar

2003-06-01

17

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

2011-01-01

18

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

19

Permian {open_quotes}Wolfcamp{close_quotes} limestone reservoirs: Powell Ranch field, Eastern Midland Basin  

Energy Technology Data Exchange (ETDEWEB)

Deep-water carbonate channel reservoirs form important oil reservoirs along the toe of the Eastern Shelf of the Permian basin in west Texas. In northwestern Glasscock County, these `Wolfcamp` reservoirs are Leonardian (Early Permian) in age and define high-energy channels incised into surrounding carbonate detritus and basinal shale. Porous grain-flow material filling these channels, along with encasing detritus, was derived from the shallow shelf located six miles to the east. Reservoirs are in packstone and grainstone facies and have significant interparticle and moldic porosity. Relevant exploration began in the 1960s, but expanded slowly thereafter due to lack of success caused by complex patterns of channel occurrence. Results of a three-dimensional (3-D) seismic survey conducted in 1990 have greatly enhanced the identification and mapping of productive channels in the Powell Ranch field complex. Wells in this complex are capable of flowing 400-1200 bbl of oil per day, and have reserves ranging from 0.2 to 1.3 MBO. The new 3-D data have improved the relevant geologic model and dramatically increased rates of drilling success. Application of such data to this setting offers a potential model for other parts of the Permian basin.

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

1996-09-01

20

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1994-01-01

 
 
 
 
21

Uranium potential in outcropping Permian basins in France and their extensions beneath mesozoic and tertiary cover  

International Nuclear Information System (INIS)

About a third of metropolitan France's uranium production is from Permian deposits located in the Lodeve and, to a lesser extent, Bourbon-l'Archambault basins. Of the Autun, west Vanoise, St-Affrique, Rodez, Brive and Var basins investigated in this study, only those of Rodez and Var have been shown to contain significant deposits. Some of the basins contain potentially interesting targets, often removed from the areas of known mineral occurrences, that have never been investigated. Geophysical exploration and drilling have shown that the Permian extends over a vast area beneath the cover of the large Mesozoic and Tertiary basins. However zones within reach of mineral exploration, ie. those less than 500 m deep, are only found in a few areas. To reach the distant targets down-dip in the outcropping basins or beneath the Mesozoic and Tertiary cover, a detailed study of the basin must be undertaken beforehand. To define and locate targets that are obviously more costly to investigate, direct methods of investigation need to be used such as drilling and geochemistry, and indirect methods such as remote sensing, geophysics and well-logging

22

Evolution of a Permian carbonate platform to siliciclastic basin: Indochina Plate, Thailand  

Science.gov (United States)

In Thailand, during the Permian, an extensive carbonate platform developed on the margin of the Indochina Plate and near to a coeval and deeper siliciclastic-dominated marine basin. This basin separated the Indochina Plate, to the east, from the Shan Thai Plate to the west. Sedimentation in the area of both platform (Pha Nok Khao Platform) and basin (Nam Duk Basin) was ended by a late Permian/early Triassic orogenic event that caused closure of the Palaeo-Tethys ocean. Tectonism has controlled the pattern of platform sedimentation and supplies of carbonate and clastic sediments into the basin area. The Pha Nok Khao Platform developed on an extensive distally steepened ramp-like margin along which carbonates and siliciclastics accumulated. Adjacent to this platform, to the west, the Nam Duk Basin received coeval hemipelagic siliciclastics and minor amounts of carbonates. Biostratigraphic evidence, based on foraminiferal assemblages, suggests an early to middle Permian age equivalence between platform and basin lithofacies. The platform strata are exposed along the Loei fold and thrust belt in northeast Thailand and basin strata are exposed within the Phetchabun fold and thrust belt in central Thailand, respectively. The two belts extend in a north-south direction and their rocks exhibit extensive karstification. On the basis of seismic data, platform lithologies extend further east in the subsurface, beneath the continental sediments of the Khorat Group into Kampuchea and Laos. Facies groups of the platform environments include restricted platform, platform interior, and outer platform. The facies groups of the basin environments include basin margin and basin plain. Minor layers of volcaniclastics and green coloured tuffites are interbedded with both the platform carbonate layers and basinal pelagic layers, suggesting active volcanism during sedimentation. The carbonate lithofacies of the shallow platform to the east (in the Loei Fold Belt) grade westward into turbidites (in the Phetchabun fold belt), and include shales and sandstones with minor carbonates. Farther to the west they pass into hemipelagic lithofacies of shale and carbonate. Lithologies and fauna of the limestones suggest tropical to subtropical climate during deposition.

El Tabakh, Mohamed; Utha-Aroon, Cherdsak

1998-10-01

23

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

24

The Devonian to Permian subsidence mechanisms in basins of the East-European platform  

Science.gov (United States)

Tectonic subsidence analysis of five major sedimentary basins of the East European platform reveals two episodes of rapid downward motion since the Devonian. The mechanisms of basin evolution are examined to explain the rapid subsidence of the basins. Models of these mechanisms are compared with seismic, gravity, heat flow and Devonian magmatism observations from the Timan-Pechora, Pre-Ural, Pre-Caspian, Dnieper-Donets and Moscow basins. The models assume that the post-Devonian development of the basins has been affected by one or more of the following processes: stretching of the lithosphere and thermal decay, mineralogical phase transition in the crust, magmatism and eclogitization-induced mantle flow in the uppermost mantle, subduction under the platform and continental collision. While some features of basin evolution are in good agreement with one of the mechanisms, no specific model can explain all features of the platform basins. Magmatism-eclogitization mechanisms are likely to be responsible for the Devonian subsidence of the Dnieper-Donets, Timan-Pechora, and Pre-Caspian basins, whereas the subduction-induced mantle flow may explain the Devonian to Permian subsidence of the Moscow basin and Pre-Ural depression.

Ismail-Zadeh, A. T.

1998-09-01

25

Fluvial architecture of Early Permian Barakar rocks of Korba Gondwana basin, eastern-central India  

Science.gov (United States)

The Early Permian Barakar Formation of the Korba basin represents repeated deposition of fining upward sequences of coarse to medium grained sandstone, fine grained sandstone-shale, shale and coal. The sandstones are channel, sheet like, multistory, and profusely cross-bedded. The shale beds are lens as well sheet like and laminated; coal facies is thin to moderately thick and shows splitting. Paleocurrent analysis suggests a northwesterly paleoslope during Barakar sedimentation. However, the deflection of paleoslope towards northeast in the eastern part of the basin supports the existence of a watershed in the depositional area. The Barakar paleochannel were 4.05 m deep and 176 m wide (single channel) with an average sinuosity of 1.27. The average flow velocity and sediment load during flood stage are in the order of 1.77 m/s and 4.15. These results indicate bed-load (braided) to mixed load nature of the Barakar streams of the Korba basin. The study suggests that the Early Permian braided Barakar streams deposited the coal measure sequence subsequent to deglaciation in a northwesterly slopping paleovalley. The basin floor was highly uneven marked by the presence of a basement high in the northwestern part that bifurcates the paleostreams into northwestern and northeastern branches.

Tewari, Ram Chandra; Hota, Rabindra Nath; Maejima, Wataru

2012-06-01

26

Socioeconomic data base report for the Permian Basin  

International Nuclear Information System (INIS)

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

27

No Abrupt Changes in redox conditions associated with the end-Permian marine ecosystem collapse in the east Greenland basin.  

DEFF Research Database (Denmark)

Multiple observations have revealed that environmental disturbances may have been linked to the end-Permian mass extinction and delayed biotic recovery. Biogeochemical constraints on the temporal and spatial changes of oceanic redox chemistry during the Permian–Triassic interval are essential to evaluate global significance of previous hypotheses and to improve our understanding of extinction and recovery processes. To investigate redox ocean chemistry change associated with the end-Permian extinction and subsequent delayed biotic recovery, we examine framboidal pyrites as well as sulfur isotopic compositions of pyrites from the East Greenland Basin. The size distributions of framboidal pyrites in sediments from a continuous section across the Permian–Triassic boundary reveal that sulfidic conditions in water columns were established about 0.7 m above the extinction event in the East Greenland Basin. Our detailed examination of framboidal pyrites challenges a leading hypothesis that euxinia in the photic zonecaused the end-Permian ecosystem collapse. We identify several positive and negative S-isotopic shifts before and after the extinction event and demonstrate that a positive S-isotopic shift is not indicative of an abrupt change of redox chemistry in water columns, in contrast to previous claims. The integration of isotope and framboidal pyrite data provides a nearly continuous record of ocean chemistry evolution and new insights into the end-Permian extinction and delayed biotic recovery in the East Greenland Basin.

Nielsen, Jesper K.; Shen, Y

2010-01-01

28

Nature and origin of fractures in Permian coals from the Bowen Basin, Queensland, Australia  

Energy Technology Data Exchange (ETDEWEB)

A field investigation into the development of cleat and other fractures within Permian coal measures was undertaken in the Bowen Basin of eastern Queensland, Australia to provide predictive information on coal permeability for use in coalbed methane exploration. Data were collected from five open-cut and three underground mines in the southern and central Bowen Basin, covering the Upper Permian German Creek Formation and Rangal Coal Measures. Fractures noted in the coals fall readily into the four categories of faults and shear zones, extension and compression-related joint sets, mining-induced fractures and coal cleats. Four geometric varieties of coal cleats were identified: class A orthogonal sets, class B sinusoidal sets, class C polygonal sets and class D chaotic sets. Superimposed or overprinted type A sets were also observed locally. On a regional scale the cleats typically parallel dip (face cleats) and strike (butt cleats), but local departures from this pattern occur in proximity to faults, where face and butt cleat directions were often reversed, rotated or multimodal. Field data suggest that coal cleats of classes A, B and C were formed by brittle fracturing of the coal during burial, whereas class D and superimposed cleats were formed during later compressional events. Constraints on the timing of deformation events affecting the Bowen Basin, and geochemical data provided by other workers indicate that the cleats were formed within 5 Ma of formation of precursor peats, but were in many instances modified by later structural events. 45 refs.

Pattison, C.I.; Fielding, C.R.; McWatters, R.H.; Hamilton, L.H. [CSIRO, Glen Waverley, Vic. (Australia). Div. of Petroleum Resources

1996-06-01

29

The uranium deposits of the Bourbon-l'Archambault Permian basin (northern Massif Central, France)  

International Nuclear Information System (INIS)

Between 1970 and 1988 significant economic uranium concentrations were discovered by CEA-COGEMA in the Bourbon-l'Archambault Permian continental basin in the northern part of the Massif Central between Moulins and Montlucon. The recent formation of some of these stratabound mineralisations in the form of vertical or slightly dipping oxidation-reduction fronts (rollfront type) in upper Autunian redbeds is particularly unusual. The geometry of the orebodies, their present depth and by their structural localisation directly beneath the Triassic unconformity are characteristic. In the same region, north of Montlucon, towards Vallon-en-Sully (in the valley of the Cher), similar deposits have been discovered in older Stephanian strata

30

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

A paleomagnetic study has been carried out on three sedimentary formations of the Permian Rodez basin in the southern France. Two of them yield paleomagnetic poles of Saxonian and Thuringian age showing counterclockwise rotation of moderate amplitude, during or after the Thuringian deposition. For the French Massif Central, contrary to its stable southern (Lodève basin) and eastern (Largentière basin) borders, on its southwestern border, in a large area including the Rodez, Saint-Affrique a...

Diego-orozco, Arturo; Chen, Yan; Henry, Bernard; Becq-giraudon, Jean-franc?ois

2002-01-01

31

A sulfur and strontium isotopic investigation of Lower Permian anhydrite, Palo Duro Basin, Texas, U.S.A  

International Nuclear Information System (INIS)

Lower Permian Wolfcamp and Wichita carbonates and anhydrites, Palo Duro Basin, Texas Panhandle, record a change from a normal marine evaporite depositional environment. Isotopic compositions of S and Sr in anhydrite were determined to investigate the age of Wolfcamp and Wichita strata and the paragenesis of eight anhydrite forms. Bedded nodular mosaic (Wichita) and replacive nodular (Wolfcamp) anhydrites have S and Sr isotopic compositions that record precipitation from Early Permian (Wolfcampian to Leonardian) seawater. Silicified nodular, coarsely crystalline nodular, fossil-filling, and vein-filling anhydrites have enriched S isotopic compositions relative to Permian seawater, whereas euhedral and anhedral replacive anhydrites have depleted S. The Sr isotopic composition of most anhydrite forms indicates an Early Permain marine origin, however, Sr in anhydrite veins is slightly radiogenic compared to Permian seawater. The Sr isotopic composition of bedded nodular mosaic anhydrite indicates a Leonardian seawater source of material. (author)

32

Geology of the Pennsylvanian and Permian Culter Group and Permian Kaibab Limestone in the Paradox Basin, southeastern Utah and southwestern Colorado  

Science.gov (United States)

The Cutler Formation is composed of thick, arkosic, alluvial sandstones shed southwestward from the Uncompahgre highlands into the Paradox Basin. Salt tectonism played an important role in deposition of the Cutler in some areas. In the northeast part of the basin, more than 8,000 ft, and as much as 15,000 ft, of arkose was trapped between rising salt anticlines - this arkose is thin to absent over the crests of some anticlines. In the western and southern parts of the basin, the Cutler is recognized as a Group consisting of, in ascending order: the lower Cutler beds, Cedar Mesa Sandstone, Organ Rock Formation, White Rim Sandstone, and De Chelly Sandstone. The aggregate thickness of these formations is less than 2,000 ft. The formations of the Cutler Group were deposited in a complex system of alluvial, eolian, and marine environments characterized by abrupt vertical and lateral lithologic changes. The basal Cutler is Pennsylvanian in age, but the bulk of the Group was deposited during the Permian. The Cutler is conformably underlain by the Pennsylvanian Hermosa Group across most of the basin. It is overlain unconformably by the Permian Kaibab Limestone in the western part of the Paradox Basin. The Cutler or Kaibab are overlain unconformably by the Triassic Moenkopi or Chinle Formations.

Condon, Steven M.

1997-01-01

33

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

International Nuclear Information System (INIS)

Closely spaced samples (285 in number) of varved sediments from the Upper Permian in Delaware Basin, Texas, have been analyzed for delta13Csub(carb), delta13Csub(org), delta18Osub(carb), Csub(org), Csub(carb) and calcite/dolomite. delta13C records a dramatic rise from -2.8 to + 5.7per mille in only 4400 years, detected in three sections across the basin, extrapolating smoothly through a 600-year interruption by a local (west side of the basin) fresh-water inflow evidenced by low delta18O. This continuity and low Csub(org) within the basin, both indicate that the excess net deposition of Csub(org), necessary to generate the rise in delta13C, took place in the ocean external to the Delaware Basin, Correlation with similar records from the Zechstein Basin suggest that the event was world-wide, although this poses obvious difficulties for the carbon cycle. The rate of rise of delta13C, and its sustained high level, must imply conversions of oxidized carbon to reduced carbon that are very large depending on which reservoirs were involved. (orig.)

34

Revised fusulinid biostratigraphic zonation and depositional sequence correlation, subsurface Permian basin  

Energy Technology Data Exchange (ETDEWEB)

Current revisions in fusulinid zonation enable them to subdivide the fossiliferous Pennsylvanian and Lower Permian section in the Permian basin into more biostratigraphic zones than the older scheme of R.V. Hollingsworth, each zone of shorter temporal duration than has previously been recognized. The identification of distinct fusulinid assemblage subzones within the absolute chronology of radiometric dating provides the basis for these stratigraphic subdivisions. The Atoka is divided into five assemblage subzones, each with an approximate duration of 1.0 m.y. In the Strawn, five subzones each of about 0.8 m.y. duration are recognized within the Cherokee; the three subzones in the Marmaton are each of 0.67 m.y. duration. Within Canyon and Cisco shelf carbonate sections are presently recognized seven and six subzones, respectively; the approximate duration of each is 0.33 and 1.03 m.y. The shelf Wolfcamp section is divisible into seven subzones, each of about 2.36 m.y. span. The entire Leonard shelf section comprises six subzones, each of about 1.83 m.y. duration; three subzones are presently recognized in the lower Leonard and three cumulatively in the middle and upper Leonard sections. These biostratigraphic subzones correspond to single or composite sediment packages (parasequences) that can be correlated regionally from shelf into basinal strata, using wireline log and conventional and processed seismic sections. Such packages comprise parts of individual depositional sequences as recognized by seismic-stratigraphic interpretations. Carbonate (various shelf and foreshelf detrital facies) and sandstone reservoirs occur within individual subzones within these sequences and can be readily defined and mapped by subsurface facies studies.

Reid, A.M.; Reid, S.T.; Mazzullo, S.J.; Robbins, S.T.

1988-01-01

35

Characteristics and formation mechanism of Permian Shanxi tight gas reservoir of Changbei gas field, Ordos Basin  

Energy Technology Data Exchange (ETDEWEB)

This paper discussed the lithological characteristics of tight gas reservoirs, including the diagenetic characteristics, diagenetic environment and diagenetic sequence. The link between porosity, the sedimentary environment, lithology, diagenesis and basin tectonics was examined in order to determine how tight reservoirs were formed. The study focused on the Changbei gas field located in Yishan Slope of the Ordos Basin in China. The main pay zone reservoir is the Upper Paleozoic Lower Permian Shanxi sandstone which lies at a depth of 2700-2950 m. This low porosity, low permeability tight gas reservoir was deposited in a coal bearing acid environment which controlled the diagenesis sequence. The early carbonate cement was not well developed because the original pore water was acidic with non saturated calcium carbonate. However, compaction has significantly reduced the original pore and pore volume. The acidic environment caused large amounts of secondary quartz cementation to fill the pores during compaction. This was the main cause for the low porosity and low permeability. Thin sections show that calcium carbonate cementation did not develop in the pores of the sandstone reservoir, particularly in the earlier stage, but autogenetic kaolinite cementation is well developed. Tectonic studies indicate that the Changbei gas field was stable when the Lower Permian Shanxi Formation was deposited. The formation layers are flat and with few faults and folds. Buried history analysis also indicates that there was no apparent uplift and subsidence after the P1S2 Shanxi Formation was deposited. Underground water, particularly organic acid and carbon dioxide acid water is not active, and pores are reduced by compaction and silicon dioxide cementation. Dissolvable components such as feldspar limited the amount of secondary pores generated, which also contributed to low porosity and low permeability. tabs., figs.

Zhong, D. [China Univ. of Petroleum, Beijing (China). State Key Laboratory of Petroleum Resources and Prospecting; Zhang, X. [PetroChina, Beijing (China). Foreign Cooperation Administration Dept.

2010-07-01

36

Radiometric age determination of tonsteins and stratigraphic constraints for the Lower Permian coal succession in southern Parana Basin, Brazil  

Energy Technology Data Exchange (ETDEWEB)

Ion microprobe (SHRIMP II) dating of zircons from tonsteins interbedded with coal seams from the Candiota and Faxinal coalfields (Early Permian, Rio Bonito Formation, Parana Basin, Brazil) is presented. The mean ages obtained (290.6 {+-} 1.5 Ma) are more precise than previously published intervals. Calibrations of chronostratigraphic data with radiometric ages show that the main coal succession from the southern Basin is constrained to the Middle Sakmarian. The {+-} 2 Ma time interval of deposition supports the hypothesis that the coal-generating process was quite rapid in terms of geological time. In a general context, Faxinal and Candiota coals are assigned, into the Protohaploxypinus goraiensis Subzone, besides some paleocological differences evidenced by palynological studies. This bio-interval does not correspond to a consistent palynostratigraphic tool and more accurate biostratigraphic zonation for the Carboniferous-Permian interval must be delineated. The new results have far-reaching significance for correlations of the Basin with sequences of the Argentinian Paganzo Basin (302 {+-} 6 Ma and 288 {+-} 7 Ma) and also with the Karoo Basin, with the lowermost Ecca Group (288 {+-} 3 Ma and 289.6 {+-} 3.8 Ma). This new evidence supports the presence of an active and widespread Lower Permian explosive volcanic event in western Gondwana, which is interpreted as the same volcanism which produced the Choiyoi Group in western Argentina. According to this correlation the ash-fall source is located about 1400 km to the southwest of their area of deposition. (author)

Guerra-Sommer, Margot; Cazzulo-Klepzig, Miriam; Hartmann, Leo Afraneo; Formoso, Milton Luis Laquintinie [Instituto de Geociencias, Universidade Federal do Rio Grande do Sul, Avenida Bento Goncalves, 9500, 91501-970 Porto Alegre, Rio Grande do Sul (Brazil); Santos, Joao Orestes Schneider [Centre for Global Targeting, University of Western Australia, Crawley, Perth 6009, WA (Australia); Ketzer, Joao Marcelo [Instituto de Meio Ambiente, Pontificia Universidade Catolica, Avenida Ipiranga, Porto Alegre, Rio Grande do Sul (Brazil)

2008-03-03

37

Phreatomagmatic Pipes of the Tunguska basin (Siberia): Aerosols Flux into End-Permian atmosphere  

Science.gov (United States)

The Tunguska Basin sedimentary sequence consists of Precambrian and Paleozoic evaporites, carbonates and terrigenous rocks including Late Paleozoic coal-bearing strata. Precambrian and early Paleozoic oil source rocks contain numerous high potential oil and gas fields. Paleozoic evaporites contain rock and potassium salts deposits of commercial grade. Tunguska Basin evaporites are considered as a regional seal for the mineralizing brines. Permian-Triassic volcaniclastic rocks overlie this sequence and intrusive rocks have the numerous evidences of magma-sediment interaction. The Siberian Traps dolerites have intruded the Tunguska Basin sequence at different levels of emplacement and magma-sediment-brine interaction result in basalt pipes formation. Intrusions are surrounded by contact aureoles of thicknesses dependent upon sediment composition, dolerite thickness, depth of emplacement and the number of intrusive bodies. The basalt pipes cutting all intrusive bodies are filled with breccias of magmatic, volcaniclastic and sedimentary rocks altered to varying extents. The age of the pipes is geologically well constrained and related to Siberian Traps intrusion emplacement. A dolerite sill intruded into rock salt sequences of the Nepa potash deposit has a U-Pb zircon age of 252 × 0.4 Ma. Basalt pipe cutting all known dolerite intrusions, revealed here during prospecting survey. The phreatomagmatic origin of the basalt pipes is supported by ubiquitous occurrence of altered sedimentary clasts and volcaniclastic lapilli, corroded by brine during initial stages of magma-evaporite (brine) interaction. Corroded lapilli have rims of diopside, chlorine-bearing hornblende, apatite and magnetite. Iron rich garnet is present on the tuff and glass fragments. Our recent study of magnetite-rich coarse lapilli tuffs revealed the specific garnet lapilli rimmed with magnetite cemented by altered clay groundmass. This result corroborates our hypothesis about magnetite formation during initial stage of magma-sediment-brine interaction. We suggest that such conclusion requires a re-examination of lapilli tuff size and composition from basalt pipes of the Tunguska Basin. We suppose that this study could shed light on our understanding of aerosols flux from the Siberian phreatomagmatic pipes and its influence on End-Permian atmosphere.

Polozov, A. G.; Svensen, H.; Planke, S.; Jerram, D. A.

2013-12-01

38

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

39

Sedimentological synthesis of permian fluviatile sediments of East Bokaro basin, Bihar, India  

Science.gov (United States)

The early Permian Karharbari and Barakar formations of East Bokaro basin comprise the following lithofacies: Lithofacies A, consisting of monomictic cobble- and pebble-conglomerate including pebbly sandstone, with faint crossbeds; deposited mainly by high-velocity aqueous currents as channel-lag deposit or longitudinal bars. Lithofacies B, coarse to medium sandstone, profusely crossbedded; interpreted as channel facies formed by downcurrent migration of sand bars in low-sinuosity streams. Lithofacies C, mainly fine sandstone with interbedded siltstone, characterised by small-scale ripple-lamination; formed in a low-energy environment such as swale-fill and/or overbank deposits. Lithofacies D, including carbonaceous shale and coal, with lack-of-current structures, indicating quiet-water deposition; interpreted as backswamp and lacustrine deposits. The overall context of the Karharbari and Barakar assemblage with relative abundance of pebbly coarse sandstone in the former and fine clastics in the latter, the presence of fining-upward cycles, widespread development of tabular and trough crossbedding and sample to sample variation of foreset azimuths, all suggest a generally alluvial environment. Analysis of crossbedding dip azimuth and dimensional fabric suggest that the sediment milieu in either case consisted of streams flowing persistently from the south-southeast to north-northwest direction. It is inferred that the unidirectional system of streams flowing across the East Bokaro basin changes systematically in channel sinuosity through time.

Khan, Zahid A.; Casshyap, Satyendra M.

1982-10-01

40

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

 
 
 
 
41

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

42

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

Scientific Electronic Library Online (English)

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

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

2011-06-01

43

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

Directory of Open Access Journals (Sweden)

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

André Jasper

2011-06-01

44

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

International Nuclear Information System (INIS)

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

45

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

Directory of Open Access Journals (Sweden)

Full Text Available A review of published papers and results of analysis of new material have allowed improvements on the palynostratigraphy of the Permian strata of the Paraná Basin in Rio Grande do Sul State. Based on first and last occurrences of certain species of pollen taxa, two palynozones are formalized, these are the Vittatina costabilis and Lueckisporites virkkiae Interval Zones, in ascending order. The Vittatina costabilis Interval Zone is subdivided into two units, in ascending order the Protohaploxypinus goraiensis and the Hamiapollenites karrooensis Subzones, and is recognized from the glacial (Itararé Group and post-glacial sequence (Rio Bonito Formation and the base of the Palermo Formation. The Lueckisporites virkkiae Interval Zone occurs from the uppermost Rio Bonito Formation, through the Palermo and Irati formations, and into the Serra Alta and Teresina formations. The main characteristics and reference sections are established, as well as additional criteria to recognize biostratigraphical units, in accordance with the International Stratigraphic Guide. Palynostratigraphical correlation suggests that the Vittatina costabilis Zone concerns the Early Permian (early Cisuralian, while the Lueckisporites virkkiae is regarded as late Early Permian to early Middle Permian (late Cisularian to early Guadalupian.

Souza Paulo A.

2005-01-01

46

Why stratigraphy and sedimentology in shales are important : an example from the Woodford Shale, Permian Basin, west Texas  

Energy Technology Data Exchange (ETDEWEB)

This presentation explained why stratigraphy and sedimentology in shales are important. The presentation provided an example from the Woodford Shale, Permian Basin, located in western Texas. Several illustrations were presented to demonstrate a stratigraphic sequence in black shale. Other topics that were discussed included geologic settings; paleogeography; silled basins; motivation for rock properties research; and factor analysis results. It was concluded that sequence stratigraphic analyses in black shales requires an integrated, multidisciplinary approach. The presentation showed that third and fourth order stratigraphic cycles are indicated by the repetition of exotic beds whose composition vary regionally. tabs., figs.

Harris, N.B. [Alberta Univ., Edmonton, AB (Canada); Colorado School of Mines, Boulder, CO (United States); Hemmesch, N.T.; Mnich, C.A. [Colorado School of Mines, Boulder, CO (United States). Geology and Geological Engineering; Aoudia, K.; Miskimins, J. [Colorado School of Mines, Boulder, CO (United States). Dept. of Petroleum Engineering

2010-07-01

47

Cycle stratigraphy and porosity in Pennsylvanian and Lower Permian shelf limestones, eastern Central Basin Platform, Texas  

Energy Technology Data Exchange (ETDEWEB)

Pennyslvanian and Lower Permian shelfal limestones were studied in core and wireline logs on the eastern side of the Central Basin platform in west Texas. Sixty-three (63) cycles were delineated in the study interval, which includes 200-250 m of Canyon (Missourian), Cisco (Virgilian), and Wolfcamp strata. Four general lithofacies are present: fossiliferous wackestones and packstones, grainstones, phylloid algal boundstones, and shales. These lithologies typically occur in 1-18-m-thick cycles bounded by subaerial exposure surfaces. Grainstones in the upper part of some cycles indicate a shallowing of environments prior to subaerial exposure. Many cycles have subaerial exposure surfaces developed on subtidal fossiliferous wackestones or packstones suggesting rapid falls in sea level. Long-term transgressive intervals (transgressive systems tracts or TST) are dominated by thick (>4 m) cycles, whereas long-term regressive intervals (highstand systems tract or HST) are dominated by thinner cycles. Stable carbon isotope data suggest that thick cycles in TSTs were subjected to short periods of subaerial exposure, whereas thin cycles in the HSTs were subjected to much longer subaerial exposure. Where present, reservoir-grade porosity occurs in the upper part of cycles, 0.3-5 m below subaerial exposure surfaces. Prolonged subaerial exposure apparently reduced matrix porosity by allowing more time for calcite precipitation, which was especially effective in reducing porosity in micritic strata below exposure surfaces.

Saller, A.H. [Unocal Energy Resources, Brea, CA (United States); Dickson, J.A.D. [Cambridge Univ. (United Kingdom); Boyd, S.A. [Unocal Energy Resources, Midland, TX (United States)

1994-12-01

48

Extent of water-rock interactions in Lower Permian Wolfcamp carbonates, Palo Duro Basin, Texas  

International Nuclear Information System (INIS)

A laterally-extensive permeable zone in upper Wolfcampian carbonate strata constitutes the first important transmissive unit below a thick evaporite sequence that is being considered for nuclear waste isolation. The extent of water-rock interaction was evaluated by comparing the chemical and isotopic composition of formation water and core collected at four DOE test wells. Wolfcamp mineralogy is dominantly calcite and dolomite with minor anhydrite at each of the four sites despite minor variations in depositional environment, diagenetic alteration, and abundance of clastic material. Isotopic compositions of calcite and dolomite and of anhydrite are within the ranges expected for Permian marine sediments altered by early diagenesis. Wolfcamp formation water compositions are more variable than host rock compositions, and are not completely controlled by local water-rock equilibria. Wolfcamp brines from two wells in the western part of the basin have depleted isotopic compositions relative to the two eastern wells and have not equilibrated with Wolfcamp carbonates, whereas the eastern fluids have. Strontium in the western samples is more radiogenic than that of the eastern samples, indicating a greater influence of clays or feldspars on the western fluids. Comparison of water and rock compositions suggests: (1) the western brines have interacted less with the carbonate host than the eastern brines due to shorter residence times or greater water: rock ratios, and (2) the r greater water: rock ratios, and (2) the minerals encountered along flow paths prior to entering the Wolfcamp are different for the western and eastern Wolfcamp brines

49

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

50

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.

Nicholas, Fordyce; Roger, Smith; Anusuya, Chinsamy.

51

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

52

Tetrapod footprints from the uppermost level of the Permian Ikakern Formation (Argana Basin, Western High Atlas, Morocco)  

Science.gov (United States)

Tetrapod footprints from the Permian Ikakern Formation of the Argana Basin have long been known but never studied in detail. Here we present the first comprehensive description of recently discovered tracks and trackways that come from near the uppermost layers of an up to 1800 m thick red-bed sequence. Assigned to HyloidichnusGilmore, 1927 and PachypesLeonardi et al., 1975, these ichnofossils suggest a Middle to Late Permian age of the track-bearing strata. Potential trackmakers are medium to large-sized moradisaurine captorhinids and pareiasaurs. This strongly parallels the bodyfossil record inasmuch as the only known skeletal remains of terrestrial tetrapods from the study area belong to both of these groups. Based on this twofold evidence, captorhinids and Pareiasauria have to be considered as abundant faunal elements of the ancient floodplain environment that is represented by the upper part of the Ikakern Formation. As one of only a few places in the world with closely associated body and ichnofossils of Late Palaeozoic age, the Argana Basin has a high potential for allowing the reconstruction of terrestrial ecosystems during the early stages of the break-up of central Pangaea and just before Mesozoic diapsid reptiles gained ascendancy. Further research on this stimulating topic will significantly contribute to the understanding of still poorly known Middle and Late Permian tetrapod ichnofaunas.

Voigt, Sebastian; Hminna, Abdelkbir; Saber, Hafid; Schneider, Jörg W.; Klein, Hendrik

2010-07-01

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

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

International Nuclear Information System (INIS)

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

55

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

56

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

57

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

International Nuclear Information System (INIS)

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

58

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

59

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

60

Mechanism of formation of hydrocarbon basins: the West Siberia, Volga-Urals, Timan-Pechora basins and the Permian Basin of Texas  

Science.gov (United States)

Many authors suggest that a large role in the formation of hydrocarbon basins is played by stretching or thrust loading. Our previous analysis (Artyushkov and Baer, 1983, 1984a,b, 1986) has revealed a large number of deep basins on continental crust in fold belts that were formed by rapid subsidence without significant stretching or thrust loading. This paper shows that the hydrocarbon basins of West Siberia, Volga-Urals, Timan-Pechora and the Permian Basin in Texas pertain to the same basin type. Water-loaded basins, ~ 0.3-0.5 km deep, were produced in these regions by rapid subsidence (in ? 1 Ma). Shallow-water and deeper-water strata cover the same area in the basins which precludes significant stretching during the subsidence. There was no folding in the adjacent regions ai the epochs of the subsidence, which precludes thrust loading. A short duration of the subsidence precludes a significant role of thermal relaxation. Rapid subsidence was commonly preceded by slight crustal uplift. In the Volga-Urals and Timan-Pechora it was also preceded by slight volcanism. We suggest destruction of the lower crust under asthenospheric upwelling to the base of the crust as a cause of rapid subsidence. The asthenospheric upwelling strongly increases the heat flow which ensures hydrocarbon maturation at shallow depth. Activization of local tectonic movements from crustal heating occurs after rapid subsidence which produces numerous traps for hydrocarbons. Deposition of highly organic rocks (good source rocks) and the formation of reefs and/or clinoforms (good reservoirs) commonly occur after rapid subsidence. Deposition of shales and evaporites (good seals) takes place in deeper-water basins formed by rapid subsidence. Diapirism of the latter rocks produces additional hydrocarbon traps. The combination of all the above effects associated with rapid subsidence produces very favourable conditions for the generation and preservation of hydrocarbons. Almost all large hydrocarbon fields in the basins considered are located in regions of rapid subsidence. There are no large fields in the adjacent sedimentary basins formed by slow subsidence, although the sediment thickness is commonly high.

Artyushkov, Eugene V.; Baer, Michael A.

1986-02-01

 
 
 
 
61

Rare Earth Elements of the Permian-Triassic Conodonts from Shelf Basin to Shallow Platform: Implications for Oceanic Redox Conditions immediately After the End-Permian Mass Extinction  

Science.gov (United States)

Rare-earth elements (REEs) can provide information regarding the influence of weathering fluxes and hydrothermal inputs on seawater chemistry as well as processes that fractionate REEs between solid and aqueous phases. Of these, cerium (Ce) distributions may provide information about variations in dissolved oxygen in seawater, and thus assess the redox conditions. The short residence times of REEs in seawater (~300-1,000 yr) can result in unique REE signatures in local watermasses. REE patterns preserved in biogenic apatite such as conodonts are ideal proxies for revealing original seawater chemistry. Here, we measured the REE content of in-situ, single albid crowns using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) in combination with an ArF (?=193 nm) excimer laser (Lambda Physiks GeoLas 2005) and quadrupole ICP-MS (Agilent 7500a). LA-ICP-MS is ideally suited for analyzing conodonts due to its ability to measure compositional variation within single conodont elements. It has the capability to determine, with high spatial resolution, continuous compositional depth profiles through the concentric layered structure of component histologies. To evaluate paleoceanographic conditions immediately after the Permian-Triassic (P-Tr) mass extinction in various depositional settings, we sampled a nearly contemporaneous strata unit, the P-Tr boundary bed, just above the extinction horizon from six sections in South China. They represent various depositional settings from shelf basin (Chaohu and Daxiakou sections), lower part of ramp (Meishan section), normal shallow platform (Yangou section), and platform microbialite (Chongyang and Xiushui sections). The sampled unit is constrained by conodonts Hindeodus changxingensis, H. parvus, and H. staeschei Zones in Meishan. REE results obtained from conodont albid crowns show that the seawater in lower ramp and shelf basin settings contains much higher REE concentrations than that in shallow platform. Ce/Ce* ratios in shelf basin and lower ramp are similar to one another, ranging from 0.7-1.0. The same ratios, however, are much lower in shallow platform and microbialite settings, ranging from 0.17-0.22 and 0.2-0.45, respectively. Eu/Eu+ ratios also show similar patterns: 0.7-1.0 in shelf basin and lower ramp and 0.3-0.7 in shallow platform. If the Ce/Ce* was truly influenced by environmental redox conditions, then Ce/Ce* values of 0.7-1.0 in shelf basin and lower ramp settings are indicative of a suboxic to anoxic depositional system, while the same proxy of 0.17-0.45 in shallow platform and microbialite points to a well-oxygenated setting immediately after the P-Tr mass extinction.

Li, Y.; Zhao, L.; Chen, Z.; Chen, J.; Chen, Y.

2013-12-01

62

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

63

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

64

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)

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2003-04-01

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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

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2006-07-15

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

International Nuclear Information System (INIS)

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

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

Directory of Open Access Journals (Sweden)

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

Luiz Eduardo Anelli

2010-07-01

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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

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

Scientific Electronic Library Online (English)

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

Paulo A., Souza; Marleni, Marques-Toigo.

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Environmental characterization of bedded salt formations and overlying areas of the Permian Basin  

International Nuclear Information System (INIS)

This report constitutes one input to the first stage of site qualification studies. It presents a general environmental characterization of the region that is underlain by the Permian bedded salt formation. The formation covers portions of Colorado, Kansas, New Mexico, Oklahoma, and Texas. The Permian bedded salt formation is one of a number of deep, stable geologic formations being studied for potential locations for nuclear waste repositories. These studies will not necessarily lead to selection of a site. They are intended only to provide information necessary to evaluate the suitability of locations for repositories. The report is intended as a general characterization of the existing environmental setting of the Permian Region with emphasis on land, water, and air characteristics; resources; plant and animal life; and man's organizations and activities. The report provides background information about the role that this regional study will play in the overall plan for environmental impact assessments and statements deemed necessary as input to the decision-making process. Background information on the present concept of nuclear waste repository design and function is also included. The information presented in this report has been summarized from open literature readily accessible to the public. No field work was conducted nor new data used in developing the descriptions contained herein

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Lower Permian facies of the Palo Duro Basin, Texas: depositional systems, shelf-margin evolution, paleogeography, and petroleum potential  

Energy Technology Data Exchange (ETDEWEB)

A Palo geological study suggests that potential hydrocarbon reservoirs occur in shelf-margin carbonates, delta-front sandstones, and fan-delta arkoses. Zones of porous (greater than 10 percent) dolomite are concentrated near shelf margins and have configurations similar to productive Lower Permian shelf-margin trends in New Mexico. Delta-front sandstones (log-computed porosity of 18 to 25 percent) are similar to producing deltaic sandstones of Morris Buie-Blaco Fields in North-Central Texas. Porous (18 percent) fan-delta sandstones along the south flank of the Amarillo Uplift may form reservoirs similiar to that of the Mobeetie Field on the north side of the Amarillo Uplife in Wheeler County, Texas. Potential hydrocarbon source beds occur in slope and basinal environments. Total organic carbon generally ranges from 1 to 2.3 percent by weight and averages 0.589 percent by weight.

Handford, C.R.

1980-01-01

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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

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Paleoenvironmental reconstitution of Motuca and Sambaíba formations, Permian-Triassic of the Parnaíba Basin in southwest Maranhão state, Brazil  

Directory of Open Access Journals (Sweden)

Full Text Available The interval between the Late Paleozoic and Early Mesozoic was marked by paleogeographic and paleoclimatic global changes, partly attributed to catastrophic events. The intense continentalization of the supercontinent Pangaea of End-Permian propitiated the development of extensive deserts that succeeded the coastal and platform environments of Early Permian. The records of these events in northern Brazil are found in intracratonic basins, particularly in the Permo-triassic succession of the Parnaíba Basin. The facies and stratigraphic outcrops analysis of this succession allowed the individualization of 14 sedimentary facies grouped into four facies associations (FA: FA1 and FA2 related to deposits of Motuca Formation and, FA3 and FA4, representative of the base of Sambaíba Formation. The FA1 – Shallow lake/Mudflat consists of red laminated mudstone with lenses of gypsum, calcite and marl, besides lobes of sigmoidal sandstones. The FA2 – Saline pan consists of lenticular bodies of laminated gypsum, nodular gypsum and gypsarenite, overlapped by greenish mudstones with dolomite nodules and palygorskite. The FA3 – sand sheet and FA4 – dunes field are formed, respectively, for orange cream sandstones with even parallel stratification and medium- to large-scale cross-bedding. In the contact between Motuca and Sambaíba formations occurs a deformed interval, laterally continuous for hundreds of kilometers. Brecciated and contorted bedded siltstones and mudstone (Motuca Formation and sandstone with sinsedimentary faults/microfaults, convolute lamination and mud-filled injection dykes (Sambaíba Formation are interpreted as seismites triggered by high magnitude earthquakes (> 8 according Richter scale.

Francisco Romério Abrantes Júnior

2013-09-01

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Morphology, intersections, and syn/late-diagenetic origin of vein networks in pelites of the Lodève Permian Basin, Southern France  

Science.gov (United States)

This paper presents the results of a field study aiming to describe and to interpret new types of relationships between vein sets. Three vein sets of the Lodève Permian Basin (Languedoc, Southern France) were studied. They consist of a family of N100E-N120E, widely opened sinuous veins with a composite infilling (sparite, calcite fibres, barite), hereafter called Sparitic Sinuous Veins, and of two orthogonal families of slim veins presenting a fibrous infilling of calcite, and oriented N10E-N20E and N90E-N100E, respectively. These two latter families are hereafter called N20 Fibrous Slim Veins and N90 Fibrous Slim Veins. The intersections between the three vein sets are shown to be original and more complex than those classically observed in the case of joint sets (abutting, crosscutting, …). The analysis of these intersections permitted a relative chronology of formation of the different vein sets to be established: the N20 Fibrous Slim Veins post-date the N90 Fibrous Slim Veins, which themselves post-date the Sparitic Sinuous Veins, the two former vein sets being shown to reopen contemporaneously. Furthermore, the vein intersections were not as simple as expected. Indeed, the successive propagating cracks of one set could in certain cases crosscut the pre-existing veins of an earlier set, or could be stopped at contact with earlier veins in other cases. This implies a physical change in the interface between the pre-existing veins and the host rock (pelites) during the formation of the latest cracks. Taking into account the well-known tectonic history of the Lodève basin, and the field observations (vein features, intersections, …), the origin of each vein set is discussed. We put forward that the Sparitic Sinuous Veins formed during the burial history of the basin: their morphological characteristics suggest that they appeared during the phase of active compaction of the basin, in response to the Permo-Triassic NS extension, and that their formation was assisted by fluid pressure. Second, we propose that the two orthogonal sets of Fibrous Slim Veins formed during the same extensional phase, their formation being favoured by the tectonic relaxation occurring at the beginning of the uplift of the basin at the end of the Permian. We attribute their particular characteristics (straight morphology of joints but systematic mineral infilling) to their origin in a medium already compacted but still incompletely lithified, and containing a large amount of fluids. We suggest that the fracturing history of the Lodève basin occurred in the time interval between the Late Permian (Thuringian) and the Middle Triassic (Anisian). Finally, the observed evolution in the propagation path between the Sparitic Sinuous Veins and the N90 Fibrous Slim Veins is discussed, and bears out the idea that the rock material was not completely lithified when the vein sets formed.

de Joussineau, Ghislain; Bazalgette, Loïc; Petit, Jean-Pierre; Lopez, Michel

2005-01-01

77

The geology petrology, palynology and geochemistry of Permian coal basins in Tanzania. 1. Namwele-Mkomolo, Muze and Galula coalfields  

Energy Technology Data Exchange (ETDEWEB)

Permian coal-bearing strata occur in a number of intracratonic rift basins in Tanzania. This study examines coals, shales and mudstones of the Namwele-Mkomolo, Muze and Galula coalfields (Rukwan basin) by coal petrological, palynological and rock eval techniques. For the coals the focus was on the establishment of coal seam characteristics and related quality and utilization potentials, whereas the shales and mudstones were examined for age relationships, flora and related palaeodepositional environments and source rock potential. The coal seams, which have a thickness of up to 2.95 m are high in ash and have calorific values ranging from 5344 to 18947 J/g. Many seams are detrital with a high content finely disseminated clay minerals, quartz and detrital macerals. Pyrite content is variable. Vitrinite reflectance ranges from 0.43 to 0.66% R{sub random}. Use of the coals in small-scale power generation and for domestic use would greatly reduce the dependency of rural Tanzania on wood and wood-derived charcoal. Palynomorph assemblages are characterized by the predominance of nontaeniate and taeniate pollen, and trilete spores in the Namwele-Mkomolo and Muze coalfields. At Galula coalfields the palynomorph assemblages were poor. On the basis of age correlations with Karoo basins to the south and the Collie Basin of western Australia, an Artinskian to Kungurian (?) age is suggested for the coal measures in the Rukwa basin. The diversity of palynomorph assemblages suggests a variety of floras and contemporary depositional environments. This is consistent with coal petrography indicating that peat accumulation occurred in upper delta plain, braided plan and lacustrine depositional environments. Rock eval parameters indicate koergen type III for all samples investigated and indicate very poor hydrocarbon source rock potential. 59 refs., 17 figs., 6 plates, 3 tabs.

Semkiwa, P.; Kalkreuth, W.; Utting, J.; Mayagilo, F.; Mpanju, F.; Hagemann, H. [Tanzania Ministry of Water, Energy and Minerals, Dodoma (Tanzania)

1998-03-01

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Nature and origin of fractures in Permian coals from the Bowen Basin and the relationship with in situ reservoir permeability  

Energy Technology Data Exchange (ETDEWEB)

As part of a broader research effort into the controls on methane generation, storage and production potential of Bowen Basin coals, this paper presents summary results of a regional investigation into the characteristics and origin of cleats and their relationship to other structures and sedimentary features associated with two major Late Permian coal measure units (German Creek Formation and Rangal Coal Measures). The aims of this study were to determine the local and regional distribution and orientation of fractures occurring naturally within coal, to investigate the relationship between cleats and other fractures (joints, shears, faults) and interpret the origin of cleats and establish a regional model for their development. Coal cleats in the Bowen Basin of eastern Queensland are interpreted to have formed by brittle failure of macerals during burial in the Permo-Triassic. The results of analysis indicate that for a given stress regime, the intensity of fracturing inherent to a coal seam has a significant impact on measured `in situ` reservoir permeability. With some refinement, and used in conjunction with measured or predicted stress data, the coal fracture index methodology may prove useful in the future as an exploration tool or aid in the generation of more reliable reservoir models. (author). 14 figs., 49 refs.

Pattison, C.I. [Geocontext Pty Ltd., (Australia); Fielding, C.R. [Queensland Univ., St. Lucia, QLD (Australia); McWatters, R.H. [Geospan Pty Ltd., (Australia); Hamilton, L.H. [Queensland University of Technology, Brisbane, QLD (Australia); Bowen Basin Geologists Group, QLD (Australia); Geological Society of Australia Inc., Sydney, NSW (Australia)

1995-10-01

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Distinction of the fluvial, aeolian and lacustrine elements of Morr o Pelado Member, Late Permian of Paraná Basin  

Directory of Open Access Journals (Sweden)

Full Text Available The Late Permian Morro Pelado Member is the upper part of the Rio do Rasto Formation of Paraná Basin and is composed of an association of fluvial, eolian and lacustrine deposits. In order to depict its facies associations and depositional elements as well as to characterize the fluvial style, a facies and architectural element analysis was carried out in the eastern outcrop belt in Santa Catarina and Paraná States, southern Brazil. Four facies associations (FA were recognized: FA-A is interpreted as mixed-load meandering fluvial systems, with conspicuous laterally accreted macroforms, levees and floodplain fines; FA-B was deposited as terminal splays in the distal parts of the fluvial system, where sheet floods prevailed; FA-C defines a fluvial-dominated lacustrine delta formed in response to episodes of extreme flooding and rising water table in the terminal splay zone; FA-D comprises eolian dunes, wet and damp interdunes and eolian sand sheets that occur interbedded with the fluvial and lacustrine deposits marking periods of aridization in the alluvial plain. The vertical stacking pattern shows an upward increase in frequency and thickness of eolian deposits recording progressive expansion of the erg systems towards basin margins in response to progressive drying combined with high rates of accommodation and sediment supply.

Danielle Cristine Buzatto Schemiko

2014-09-01

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Linking the End of Glaciation in Gondwana to Aridity in the Tropics: Coupled Sr Chemostratigraphy and Cyclostratigraphy From the Permian Basin, Texas  

Science.gov (United States)

Crowell (1978) suggested the Earth was poised on the brink of glaciation throughout the Paleozoic and that closure of the low-latitude seaway between North America and Europe was responsible for diversion of moisture- laden currents to the south to feed the long-lived Carboniferous-Permian glaciers. This same diversion of currents also produced dramatic aridity in the tropics. This is seen in changes in paleosol types as well as in widespread loess and erg deposits. It also coincides with a dramatic decline in Sr isotopes across the Carboniferous-Permian boundary. Sr chemostratigraphy from cores taken across this boundary on the Central Basin Platform (CBP) of the Permian Basin in Texas show the same dramatic shift as seen in data from the type sections in the Urals across this boundary. This confirms that the fusulinid based stage boundaries for the Permian Basin are correct. On the CBP, high-frequency high-amplitude cycles end at a major stepback of the shelf margin at Abo/Clearfork time (Sakmarian). We suggest this transgression represents the end of major Gondwanan glaciation. If we assume the decline in 87Sr/86Sr is reflecting the aridity of the topics and calculate the reduction in continental Sr flux to the oceans, we can relate this to decreased silicate weathering and the consequent increase in atmospheric CO2. Assuming crustal values of [Sr] of 350 ppm, congruent weathering, that the total number of moles of Sr in the ocean is the same as today, and that all of the change is due to a change in flux of Sr from the continents, the change from a late Carboniferous 87Sr/86Sr high of 0.7082 to a value of 0.7078 (the end of cyclothems), equates to an increase in the ocean-atmosphere system of approximately 4 * 106 gigatons of carbon. Preindustrial carbon concentration in the atmosphere is estimated at 578 gigatons. Obviously there are feedbacks that will remove some of the carbon from the ocean-atmosphere system, perhaps to the biosphere, but this simple calculation shows that no special circumstances are needed to account for the increase in pCO2 shown by published proxy data. It also demonstrates why a model that only considers tectonic changes might fail to reproduce this part of the Sr curve. However, the 87Sr/86Sr continues to decrease to a late Permian low of 0.7069 without reversal while the proxy data show a decrease in pCO2 in the middle Permian to near Carboniferous values. Nevertheless, the change is coincident with a flattening in the most recently published Permian Sr curve.

Rasbury, E. T.; Hemming, N. G.; Saller, A. H.; Dickson, J.

2007-05-01

 
 
 
 
81

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)

82

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

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Permian rhyolitic volcanism, changing from subaqueous to subaerial in post-Variscan intra-continental Sirinia Basin (SW Romania-Eastern Europe)  

Science.gov (United States)

The Sirinia Basin is a well-exposed, Upper Carboniferous-Lower Permian intra-continental extensional basin, containing 1-2 km of Permian interbedded terrigeneous sediments and primary volcanic and volcaniclastic rocks of rhyolitic composition. These are mostly the products of subaqueous volcanism passing into a subaerial volcanism. The intra-continental basin lies on the Danubian metamorphic units in the south westernmost part of the Carpathians (SW Romania) and is N-S oriented (18 × 8 km), as result of Alpine tectonic evolution and deformation. The Sirinia Basin setting formed a dynamic closed intra-continental sedimentary system that experienced a successive subsidence; it started with lacustrine sediments and then with large volumes of rhyolitic volcanic and volcaniclastic material dominantly sited in the central part of the basin. Volcanism included (1) subaqueous extrusion of domes surrounded by hyaloclastite deposits closely associated with secondary sedimentation, (2) extrusive and explosive Surtseyan-type and subaerial eruptions from shallow water to emergent volcanoes on dome-cap and associated reworked deposits, towards the southern side of the basin, and (3) subaerial extrusive domes. Fluvial erosion and deposition completed the evolution of the emerged marginal part of the basin. Most of the erupted material of the first and second phase filling the central part of the basin along extensional normal faults was rapidly transported on sides of the basin by turbidite sedimentation, debris flows, slumping and sliding. While turbidites prevail toward the central part of the basin, the debris flow sedimentation predominated at the margin of the basin, infrequently interrupted by deposition of fallout ash from hydromagmatic explosive eruptions related to the dome-cap tuff and pumice cones.

Seghedi, Ioan

2011-04-01

84

Permian to Late Triassic evolution of the Longmen Shan Foreland Basin (Western Sichuan): Model results from both the lithospheric extension and flexure  

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The lithosphere was extended during the Permian-Middle Triassic in the Yangtze Craton where the Sichuan Basin located, and then bent due to thrusting of the Longmen Shan orogen, leading to formation of the Longmen Shan Foreland Basin (Western Sichuan) during the Late Triassic Indosinian orogeny. The lateral variation of the lithospheric strength resulted by former differential extension would inevitably influence the subsequent evolution of the foreland basin. In order to investigate this, both extensional and flexural models were applied in modeling Permian-Late Triassic basin evolution. A 2D kinematic extensional model was initially developed along a profile crossing the Yangtze Craton to simulate the lithospheric thermal evolution during the Permian-Middle Triassic. Based on the thermal results, the thermal-rheological structure, as well as the effective elastic thickness of the lithosphere (Te), was then determined. Extension model show that the stretching factors decrease gradually from Songpan-Ganzi to the Sichuan Basin, leading to variable thermal-rheological structure and increased Te from west to east. Taking into account of the Te variation, a flexural model was finally constructed to investigate the evolution of the Longmen Shan Foreland Basin during the Late Triassic spanning the time period c. 227-206 Ma. Three episodes were divided according to the corresponding tectonostratigraphic units. By matching the stratigraphic observations, three phase advance distances eastward of the Longmen Shan along the Qingchuan-Maowen Fault turned out to be 18, 22, and 18 km. It implied a slow and similar thrust advance rate of 3.6 (c.227-222 Ma), 2.2 (c.222-212 Ma), and 3 mm/yr (c.212-206 Ma), respectively.

He, Lijuan

2014-10-01

85

Distribution of soft-sediment deformation structures in clinoform successions of the Permian Ecca Group, Karoo Basin, South Africa  

Science.gov (United States)

The stratigraphic distribution of two groups of soft-sediment deformation structures (SSDS) - detached (dominated by lateral movement forming slides and slump deposits, and debrites) and in situ (dominated by vertical movement forming flame structures, pseudonodules, and ball-and-pillow structures) - are compared in two Permian successions in the Tanqua and Laingsburg depocentres of the Karoo Basin. SSDS occur in a series of well-exposed 40 to 55 m thick sedimentary cycles. Cycle thicknesses decrease upwards and the proportion of deformed strata is around 30% in both successions. Each flooding surface-bounded cycle is characterized by a lower unit dominated by thin-bedded turbidites, overlain by an intermediate section dominated by soft-sediment deformed facies, above which are undeformed thick-bedded mouthbar and shoreface sandstones. The upper part of each cycle fines upwards into thin-bedded turbidites, which are overlain by the cycle-bounding flooding surface. The cycles, and the distribution of SSDS, are the response to delta outbuilding and retreat over a clinoform rollover and onto a clinoform slope. Repeatable trends in the distribution of SSDS during the evolution of clinoforms in both depocentres indicate a level of stratigraphic organisation and predictability in the otherwise complicated record of processes around the clinoform rollover.

Oliveira, Carlos M. M.; Hodgson, David M.; Flint, Stephen S.

2011-04-01

86

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

87

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

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

Mikuláš R

2006-03-01

88

Magmatic flare-up at the Carboniferous/Permian boundary in the NE German Basin revealed by SHRIMP zircon ages  

Science.gov (United States)

SHRIMP ages of 12 volcanic samples indicate intense magmatic activity to have occurred at the Carboniferous/Permian boundary throughout much of the NE German Basin. Rhyolitic crystal-rich samples have been taken from quarries in the Halle Volcanic Complex (HVC) and in the Flechtingen Ignimbrite, and from drill cores of the Kotzen, Mirow, Friedland and Penkun areas. Ten samples yielded 206Pb/ 238U ages between 302 and 297 Ma (±3 Ma, respectively) which indicate that the magmatic activity took place concentrated in a relatively short time span throughout much of the NE German Basin. Two HVC samples have ages of 307 and 294 Ma. This remarkably synchronous magmatic activity occurred during the initial phase of the basin development. Considering published volume estimates (48,000 km 3), extrusion rates during this time period probably were in the order of 0.01 km 3 a -1, implying magma production rates of 0.1 km 3 a -1. The calc-alkaline SiO 2-rich volcanic rocks originated from magmas that presumably formed during anatexis and subordinate magma mixing in an intra-continental transtensional setting. The basaltic magma which must have provided the thermal input into the lower crust probably formed during decompressional melting of lithospheric mantle fertilised by previous magmatic processes. The dated volcanic rocks occur in three geotectonic provinces, namely the (a) Mid German Crystalline Rise, which forms the northern part of the Internal Variscides, the (b) External Variscides and the Variscan foreland which is considered as (c) Eastern Avalonia. Many of the old zircons found in the HVC samples reflect the magmatic activity of the Mid German Crystalline Rise (325-400 Ma). However, Cadomian (500-650 Ma) and older Gondwanian elements (1674-2373 Ma) are also present. Although the Flechtingen and Kotzen areas are located within the External Variscides, it seems more likely that the middle to lower crust, that experienced anatexis, formed part of the Eastern Avalonia Plate overridden by the Variscan Front. Thus the old zircons found in Flechtingen (350 and 538 Ma) and Kotzen (345 Ma), but certainly those present in the Penkun drill cores (1483 Ma) represent Eastern Avalonia tectonic history. The anatectic magmas in the Friedland area probably formed partly from Baltic crust thrusted below Eastern Avalonia during the Caledonian Orogeny. Among the old zircons from the Friedland samples, in addition to Proterozoic ages (1456 Ma), we found testimony of Caledonian (443 Ma) and of clearly post-Caledonian (387 Ma) magmatism.

Breitkreuz, Christoph; Kennedy, Allen

1999-02-01

89

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

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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

90

Kinetics of evaporite mineral-brine interactions: mathematical modeling and experimental determination of the effect of gamma radiation and threshold crystallization inhibition on Permian Basin brine composition  

International Nuclear Information System (INIS)

The San Andres and Salado bedded salt formations in the evaporitic Permian Basin contain fluid phases in equilibrium with the host rock. Anthropogenic perturbations such as emplacing heat-generating high level radioactive wastes (HLW) in a mined repository mobilize this brine. Kinetic factors are of extreme importance in the precipitation and dissolution of evaporites and may govern the diagenesis of phosphate, sulfate, and chloride phases in the type of environment occurring at both the time of the original deposition of the sediment and in the very nearfield of a HLW repository. Using the computer code XLRATE, newly-formulated geometric models incorporating critical aspects of mineralogical defects and dislocations describe a wide variety of kinetic data for the dissolution of apatite and irradiated Permian Basin rock salt. The lattice damage in rock salt caused by gamma radiation increases the halite dissolution rate. The escape of chlorine gas and the radiolysis of trace impurities moves the NaCl concentration of saturated brines made from irradiated salt to lower values with Cl- decreasing to a greater extent than Na+. A new model incorporating nucleation time best describes crystallization kinetics in the calcium sulfate system. The solubilities and saturation indices of irradiated Permian Basin rock salt and calcium sulfates in brines of different ionic strengths were numerically modeled. Seventy-five naturally-occurring and commercial cryive naturally-occurring and commercial crystallization inhibitors including carboxylic acids, amino acids, carbohydrates, humic and tannic substances, and organic polyelectrolytes were tested for their effect on gypsum/anhydrite and rock salt precipitation and dissolution. Of these, 70% proved relative or very effective

91

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

92

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

93

Paleomagnetic and 40Ar/39Ar results from the Grant intrusive breccia and coparison to the Permian Downeys Bluff Sill; evidence for Permian igneous activity at Hicks Dome, southern Illinois Basin  

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Igneous processes at Hicks dome, a structural upwarp at lat 37.5 degrees N., long 88.4 degrees W. in the southern part of the Illinois Basin, may have thermally affected regional basinal fluid flow and may have provided fluorine for the formation of the Illinois-Kentucky Fluorspar district. The timing of both igneous activity and mineralization is poorly known. For this reason, we have dated an intrusive breccia at Hicks dome, the Grant intrusion, using 40Ar/39Ar geochronometric and paleomagnetic methods. Concordant plateau dates, giving Permian ages, were obtained from amphibole (272.1+or-0.7 [1 sigma] Ma) and phlogopite (272.7+or-0.7 [1 sigma] Ma). After alternating-field (AF) demagnetization, specimens that contain titanomagnetite-bearing igneous rock fragments give a mean remanent direction of declination (D)=168.4 degrees; inclination (I)=-8 degrees; alpha 95=8.6 degrees; number of specimens (N)=10; this direction yields a virtual geomagnetic pole (VGP) at lat 54.8 degrees N., long 119.0 degrees E., delta p=4.4 degrees, delta m=8.7 degrees, near the late Paleozoic part of the North American apparent pole wander path. A nearly identical magnetization was found for the nearby Downeys Bluff sill (previously dated at about 275+or-24 Ma by the Rb-Sr method), in southern Illinois. Both AF and thermal demagnetization isolated shallow, southeasterly remanent directions carried by magnetite in the sill and from pyrrhotite in the baked contact of the Upper Mississippian Downeys Bluff Limestone: D=158.6 degrees; I=-11.8 degrees; alpha 95=3.8 degrees; N=15, yielding a VGP at lat 53.0 degrees N., long 128.7 degrees E., delta p=2.0 degrees, delta m=3.9 degrees. The paleomagnetic results, isotopic dates, and petrographic evidence thus favor the acquisition of thermal remanent magnetization by the Grant breccia and the Downeys Bluff sill during the Permian. The isotopic dates record rapid cooling from temperatures greater than 550 degrees C to less than 300 degrees C (the closure temperatures for diffusion of 40Ar in amphibole and phlogopite, respectively) after emplacement during the Permian. The results further indicate that individual clasts of the Grant breccia were emplaced at temperatures greater than about 550 degrees C, the magnetization-blocking temperature of the titanomagnetite in the breccia, and that it cooled very rapidly,within less than 1-2 m.y. After cooling, the breccia was not affected by thermal perturbations greater than about 300 degrees C.

Reynolds, Richard L.; Goldhaber, Martin B.; Snee, Lawrence W.

1997-01-01

94

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)

95

CO2 Sequestration in the Permian Basin SACROC Northern Platform, Site of 35 Years of CO2 Injection  

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We are developing a comprehensive model for understanding effects of decades of CO2 injection at SACROC (Scurry Area Canyon Reef Operators Committee), a carbonate reef complex in the Permian Basin of west Texas. SACROC is the oldest CO2 enhanced oil recovery site in the United States, with CO2 injection since 1972. For the past 35 years, more than 55 million tons of CO2 have been injected in SACROC. For comparison, the Sleipner project in Norway has injected about 1 million tons CO2 per year since 1996 and the Weyburn project in Canada has injected about 2 million tons CO2 per year since 2000. In terms of its history and the amount of CO2 injected, the SACROC unit, as an anthropogenic analog site for CO2 sequestration, provides an excellent opportunity for in-situ studies of subsurface CO2 migration, seal integrity, and induced changes of reservoir properties. According to detailed well records for the Northern Platform area, 13 million tons of CO2 have been injected, 6 million tons of CO2 produced, and 7 million tons of CO2 still remain in this part of the field. We assembled a model of the Northern Platform area for this analysis. The three-dimensional distribution of porosity and permeability of the field was estimated based on seismic and core data. The analysis of water chemistry data from both fresh water and production formations suggests that Wolfcamp shale acts as a suitable seal. We used these data to parameterize a 3-D multiphase, reactive transport model of the field. Model results indicate that the migration patterns of separate CO2 are different within the western and eastern flanks because of reservoir heterogeneity. In addition, we discerned the existence of preferential flow paths within the field. Furthermore, we evaluated possible changes in porosity and permeability by CO2 with simulations of multispecies reactive transport. Simulation results suggest that diagenetic reactions induced by CO2 injection are a viable explanation for major changes in reservoir properties, even at decadal time scales

Han, W.; McPherson, B.; Wang, F. P.

2006-12-01

96

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  

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Full Text Available 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. The heavy mineral associations of the sandstone matrix of these conglomerates support this interpretation. Crystalline units of the south-western part of the Krkonoše-Jizera Crystalline Complex and Orlice-Sn?žník Crystalline Complex, respectively, are considered as the most favourable sources. Heavy mineral associations of fluvial sandstone facies are of complex composition pointing to repeated recycling of clastic material. However, heavy mineral indices reveal distinct source areas for the main lithostratigraphic units. Two main possible source areas for the fluvial Asselian deposits (Vrchlabí Formation of the south-western part of the basin were found. Pebbles of late Devonian- early Carboniferous marine limestones probably came from the central part of the hypothetical Jítrava-Hradec Basin. The garnet compositions in sand detrital material point to leucogranites and pegmatites of the north-eastern Moldanubian Zone, P?ibyslavice area, as the possible source rocks. Guadalupian fluvial deposits reveal a wide range of sources that can be attributed to the recycling of detrital material from Cisuralian and Carboniferous deposits. Garnet compositions indicate Moldanubian granulites, garnet clinopyroxenites, leucogranites and pegmatites as a possible sources. We infer that Moldanubian granulites and garnet clinopyroxenites were exposed to an erosion level in the Early Permian at the latest.

Martínek K

2009-09-01

97

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

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

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

2010-12-01

98

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

99

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

Science.gov (United States)

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

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

2013-08-01

100

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2006-08-01

 
 
 
 
101

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

102

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

103

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

Energy Technology Data Exchange (ETDEWEB)

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

Erdlac, Richard J., Jr.

2006-10-12

104

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

105

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

Science.gov (United States)

This article integrates faciological, paleobotanical, and palynological analyses to establish the relationship between depositional cyclicity and paleoecological patterns for the (Early Permian) Quitéria outcrop, Rio Bonito Formation, southern Paraná Basin, Rio Grande do Sul state. The basal section of this outcrop represents a coastal lagoon depositional system protected by barriers in microtide conditions, where peat-forming conditions developed in lowlands with ingression of distal alluvial fan deposits. The upper clastic section represents different environmental conditions, originated by the barrier sectioning brought by washover fans. The palynoflora identified in the basal section present a dominance of spores produced by arborescent and herbaceous lycophytes, as well as by sphenophytes and filicophytes, complementary forms of gymnosperm pollen grains. Algae or algae-elements, indicative of fresh, brackish, or marine water, are recorded together with terrestrial spores and pollen grains. The palynological content of matrix-supported conglomerates suggests a close, qualitative similarity with the coaly facies; however, the increase in gymnosperm pollen grains accompanied by a decrease in spores produced by pteridophyte vegetation is remarkable. The autochthonous roof-shale flora related to the clastic upper section is composed of basal stumps of arborescent cormose lycophytes ( Brasilodendron pedroanum), understory vegetation ( Botrychiopsis valida, Lycopodites sp.), small trees ( Coricladus quiteriensis), undetermined filicoid rodheopterid fronds, and parautochthonous elements ( Rubidgea sp., Cordaites sp.). Palynofloras point to floristic similarity between the roof-shale floras and the subjacent coal-forming parautochthonous floras. Correlations between the floristic data and those from high-resolution sequence stratigraphic methods indicate that this interval is associated with the final parasequences of the transgressive tract of Rio Bonito Formation, where coal levels are thin. The record in some coal palynofloras of Striadopodocarpites fusus, a component of the Hamiapollenites karrooensis subzone, as defined in the palynostratigraphic framework for the Paraná Basin, indicates a Kungurian age for the palynoflora.

Jasper, André; Menegat, Rualdo; Guerra-Sommer, Margot; Cazzulo-Klepzig, Miriam; de Souza, Paulo Alves

2006-07-01

106

Geoscience/engineering characterization of the interwell environment in carbonate reservoirs based on outcrop analogs, Permian Basin, West Texas and New Mexico - petrophysical characterization of the South Cowden Grayburg Reservoir, Ector County, Texas. Final report  

Energy Technology Data Exchange (ETDEWEB)

Reservoir performance of the South Cowden Grayburg field suggests that only 21 percent of the original oil in place has been recovered. The purpose of this study is to construct a realistic reservoir model to be used to predict the location of the remaining mobile oil. Construction of reservoir models for fluid-flow simulation of carbonate reservoirs is difficult because they typically have complicated and unpredictable permeability patterns. Much of the difficulty results from the degree to which diagenetic overprinting masks depositional textures and patterns. For example, the task of constructing a reservoir model of a limestone reservoir that has undergone only cementation and compaction is easier than constructing a model of a karsted reservoir that has undergone cavern formation and collapse as well as cementation and compaction. The Permian-age carbonate-ramp reservoirs in the Permian Basin, West Texas and New Mexico, are typically anhydritic dolomitized limestone. Because the dolomitization occurred soon after deposition, depositional fabrics and patterns are often retained, and a reservoir model can be constructed using depositional concepts. Recent studies of the San Andres outcrop in the Guadalupe Mountains and the Seminole San Andres reservoir in the Permian Basin illustrate how depositional fabrics and patterns can be used to construct a reservoir model when depositional features are retained.

Lucia, F.J.

1997-06-01

107

Permian age from radiolarites of the Hawasina nappes, Oman Mountains  

Science.gov (United States)

The Hawasina nappes of the Oman Mountains yielded Permian radiolarians from cherts stratigraphically overlying a thick volcanic basement (AI Jil Formation) at the base of the Hamrat Duru Group. This fauna represents the first Permian radiolarians and radiolarites in the central and western Tethyan realm. A Permian age for pelagic sequences within the Hawasina Complex of Oman has major significance for regional paleogeographic reconstruction. A clear differentiation between platform (reefal sediments) and basin (radiolarites) from the base of the Late Permian (255 Ma) is implied. It suggests a flexure of the platform during Permian time; the present date implies that a zone of rifting was already developed adjacent to the northeast Gondwana platform margin during the Late Permian. The Hamrat Duru Basin corresponds to an opening intracontinental rift area (sphenochasm) between Arabia and northeast Gondwana, a reentrant of the paleo-Tethys.

de Wever, Patrick; Bourdillon-de Grissac, Chantal; Bechennec, François

1988-10-01

108

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

109

Origin of CO{sub 2}-rich gas in the Permian coal measures of the northern Sydney Basin, NSW, Australia  

Energy Technology Data Exchange (ETDEWEB)

Areas where CO{sub 2} is present at high concentrations (6-100%) are considered to be less attractive for coal bed methane (CBM) exploration. In the Sydney Basin CO{sub 2} as a proportion of the total gas can range from 0.1% to in excess of 90% and so geographic and stratigraphic variability of CO{sub 2} in coal seams, along with parameters such as methane content and coal permeability, have become of prime importance for successful CBM production. Before a full-scale CBM project can be undertaken in the Sydney Basin, reasons for high CO{sub 2} content and the controls on its distribution need to be identified. This paper reports the results of a study conducted to determine a) in-seam and inter-seam distribution of CO{sub 2} and b) source of CO{sub 2} particularly where it is present in high proportions, in exploration leases held by Pacific Power in the Sydney Basin. The data for this study were collected mainly from 3 exploration wells drilled by Pacific Power. Additional information was collected from Ellalong Colliery and from Dartbrook Mine both in the Hunter Valley. 13 refs., 7 figs., 1 tab.

Kozyrev, N.; Skilbeck, C.G. [University of Technology, Sydney, NSW (Australia). Dept. of Applied Geology

1997-08-01

110

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 ey, 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

111

Rock-physics-based carbonate pore type characterization and reservoir permeability heterogeneity evaluation, Upper San Andres reservoir, Permian Basin, west Texas  

Science.gov (United States)

In addition to mineral composition and pore fluid, pore type variations play an important role in affecting the complexity of velocity-porosity relationship and permeability heterogeneity of carbonate reservoirs. Without consideration of pore type diversity, most rock physics models applicable to clastic rocks for explaining the rock acoustic properties and reservoir parameters relationship may not work well for carbonate reservoirs. A frame flexibility factor ( ?) defined in a new carbonate rock physics model can quantify the effect of pore structure changes on seismic wave velocity and permeability heterogeneity in carbonate reservoirs. Our study of an Upper San Andres carbonate reservoir, Permian Basin, shows that for core samples of given porosity, the lower the frame flexibility factor ( ?), the higher the sonic wave velocity. For the studied reservoir, samples with frame flexibility factor ( ?) 3.85 indicate either dominant interparticle pore space in dolopackstone or microcrack pore space in dolowackstone or dolomudstone. Using the frame flexibility factor ( ?), different porosity-impedance and porosity-permeability trends can be classified with clear geologic interpretation such as pore type and rock texture variations to improve porosity and permeability prediction accuracy. New porosity-permeability relations with ? classification help delineate permeability heterogeneity in the Upper San Andres reservoir, and could be useful for other similar carbonate reservoir studies. In addition, results from analysis of amplitude variation with offset (AVO) and impedance modeling indicate that by combining rock physics model and pre-stack seismic inversion, simultaneous estimation of porosity and frame flexibility factor ( ?) is quite feasible because of the strong influence of carbonate pore types on AVO especially when offset is large.

Dou, Qifeng; Sun, Yuefeng; Sullivan, Charlotte

2011-05-01

112

Depositional and diagenetic aspects of siliciclastic and carbonate reservoirs in Glorieta Formation (Permian), northern Midland basin, Texas  

Energy Technology Data Exchange (ETDEWEB)

The Glorieta formation is oil productive in the northern Midland basin. Production through 1982 totaled over 25 million bbl of oil. Carbonate as well as siliciclastic facies are productive in different locations on the shelf. This production is largely diagenetically controlled, with secondary porosity enhancement prevalent in both clastic and carbonate reservoir types. The Glorieta formation is composed of cyclically deposited siliciclastics, carbonate, and carbonate-evaporite units. Environments of deposition range from supratidal sabkha through shallow subtidal to open-marine conditions. The siliciclastics are eolian-derived sediments that prograded onto the shelf of the northern Midland basin. The overall coarsening-upward sequence, the gently seaward dip of the clastics, and the open-marine characteristic of adjacent carbonate sediments suggest a subaqueous deposition similar to that described by Shinn along the leeward, southeast coast of Qatar Peninsula in the Persian Gulf. Diagenetic features affecting porosity development in the siliciclastic intervals include etching of quartz grains and penecontemporaneous precipitation of pore-filling, poikilotopic anhydrite cement. Subsequent partial dissolution of anhydrite cements increased porosity in clastic reservoir facies. The carbonate units have undergone pervasive dolomitization of mud matrix, leaching of allochems, and extensive anhydrite void filling. Replacement of dolomicrite by anhydrite and later solutioning of replacement fabric anhydrite contributed to secondary porosity in carbonate reservoirs. A better understanding of these diagenetic relationships could aid in predicting porosity trends in these distinctly different reservoir types within the Glorieta formation.

Davidson, W.T.

1985-02-01

113

Depositional environments and sequence stratigraphy of the Late Carboniferous-Early Permian coal-bearing successions (Shandong Province, China): Sequence development in an epicontinental basin  

Science.gov (United States)

This study focuses on the Late Carboniferous-Early Permian coal-bearing successions in Shandong Province, North China in order to understand the depositional processes and sequence-stratigraphic framework in an epicontinental basin. Based on detailed analysis of eleven facies, five facies assemblages (FAs) were recognized in the studied succession. FA1-3 are present mainly in the Benxi and Taiyuan formations, and consist of mixed siliciclastic and carbonate lithofacies, representing eluvial-lagoon, barrier-lagoon, and tidal-flat environments. FA4 occurs in the Shanxi formation and consists mainly of interbedded medium to fine sandstone, siltstone, mudstone, and coal lithofacies, representing river-dominated deltaic environments. FA5 is characterized by interbeds of trough cross-stratified coarse sandstone, and silty mudstone, mainly in the Lower Shihezi Formation, which was deposited in meandering river channel and floodplain. Three third-order sequences were established based on the vertical arrangement of facies assemblages and identification of physical surfaces (i.e., subaerial unconformity, transgressive surface, and regressive surface). Each sequence comprises a transgressive systems tract (TST) and a highstand systems tract (HST). TST of sequence 1 is composed of eluvial lagoonal deposits (FA1), whereas HST formed in lagoon-barrier and tidal-flat settings (FA2 and FA3). TST of sequence 2 formed in a barrier-lagoon system (FA2), whereas HST is characterized by repetitive accumulation of interbedded limestone, sandstone, mudstone, and coal, deposited under lagoonal and tidal-flat settings (FA2 and FA3). TST of sequence 3 comprises FA2, and HST mainly FA4, deposited in a river-dominated shallow-water delta system. Sequence 3 is overlain by a fluvial sequence (FA5). The three third-order sequences in the Shandong region are generally correlated with those in the Taebaeksan Basin (South Korea), the eastern part of the North China Block. The relative sea-level curves established in the two regions show a generally similar long-term rising trend.

Lv, Dawei; Chen, Jitao

2014-01-01

114

Cyclicity in early Permian fluviatile Gondwana coal measures: An example from Giridih and Saharjuri basins, Bihar, India  

Science.gov (United States)

The Karharbari and Barakar coal measures of Giridih and Saharjuri basins of Bihar, eastern India, comprise an interbedded assemblage of sandstone, shale and coal in variable abundance. The lithofacies composition records a progressive decrease in sandstone and enrichment of shale and coal from Karharbari up to Barakar. Application of first-order embedded Markov-chain statistics to subsurface data of Karharbari (52 borehole logs) and Barakar (10 borehole logs) reveals that deposition in both the coal measures followed a Markovian mechanism with variable probability, to yield a sequence of upward transition from sandstone through shale to coal. The repetitive fining-upward cycles are asymmetrical, i.e. sandstone ? shale ? coal ? sandstone in the case of Karharbari, but symmetrical as sandstone ? shale ? coal ? shale in Barakar. The abundance of sandstone and the asymmetrical nature of Karharbari cycles are attributed to abrupt shifting of channel bars in low-sinuosity anabranching streams. By contrast, the subequal amount of sandstone, shale and coal forming symmetrical cycles in the overlying Barakar Formation is due perhaps to a slow and gradual shift of the stream channels over and across the adjacent subenvironments of the flood plain.

Tewari, Ram C.; Casshyap, Satyendra M.

1983-08-01

115

Permian age from radiolarites of the Hawasina nappes, Oman Mountains  

Energy Technology Data Exchange (ETDEWEB)

The Hawasina napper of the Oman Mountains yielded Permian radiolarians from cherts stratigraphically overlying a thick volcanic basement (Al Jil Formation) at the base of the Hamrat Duru Group. This fauna represents the first Permian radiolarians and radiolarites in the central and western Tethyan realm. A Permain age for pelagic sequences within the Hawasina Complex of Oman has major significance for regional paleogeographic reconstruction. A clear differentiation between platform (reefal sediments) and basin (radiolarites) from the base of the Late Permian (255 Ma) is implied. It suggests a flexure of the platform during Permian time; the present data implies that a zone of rifting was already developed adjacent to the northeast Gondwana platform margin during the Late Permian. The Hamrat Duru Basin corresponds to an opening intracontinental rift area (sphenochasm) between Arabia and northeast Gondwana, a reentrant of the paleo-Tethys.

Wever, P.D. (Universite Pierre et Marie Curie (France)); Grissac C.B. (Bureau de Recherche Geologique et Miniere, Orleans, (France)); Bechennec, F. (Bureau de recherche Geologique et Miniere, Nantes (France))

1988-10-01

116

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.

117

Palynological resolution of Permian sequence in Ib-River coalfield, Orissa and its environmental significance  

Energy Technology Data Exchange (ETDEWEB)

The Ib-River coalfield, a part of Mahanadi Master Basin has rich deposit of Lower Permian Barakar coal. The palynological analysis of sediments from this coalfield has revealed the presence of distinct palynoassemblages. These assemblages represent Permian sequence from Lower Barakar (Early Permian) to Lower Kamthi (Late Permian) sediments. The present palynological studies help in redefining the status of Barakar and Kamthi Formations and in classifying them. Here the palynological assessment has been compared with the megafossil work of the author. Based on the palaeobotanical data, the stratigraphy of this coalfield has been proposed and the environment during Permian time has been discussed in this paper.

Goswami, S. [Fakir Mohan University, Vyasa Vihar (India). PG Dept. of Environmental Science

2007-07-15

118

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Jacqueline Peixoto Neves; Rosemarie Rohn Davies; Marcello Guimarães Simões

2011-01-01

119

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in spanish Cinco nuevas edades radiométricas logradas mediante análisis U-Pb en circón utilizando el SHRIMP, fueron determinadas en gneises y rocas plutónicas foliadas obtenidas desde el fondo de pozos de sondajes en la Cuenca de Magallanes y pertenecientes al denominado Complejo ígneo y Metamór-fico de Tierra [...] del Fuego. En tres de las muestras fueron calculadas edades del Cámbrico Temprano (523±7 Ma, 522±6 Ma y 538±6 Ma), interpretadas como edades de cristalización 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. Abstract in english Five new SHRTMP U-Pb zircon ages are reported for gneisses and foliated plutonic rocks belonging to the Tierra del Fuego igneous and metamorphic basement complex (TFIMC), obtained from the bottom of borehole cores through the Magallanes Basin. Three of the samples yielded weighted mean 206Pb/238U ag [...] es (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.

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

2010-07-01

120

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in spanish Cinco nuevas edades radiométricas logradas mediante análisis U-Pb en circón utilizando el SHRIMP, fueron determinadas en gneises y rocas plutónicas foliadas obtenidas desde el fondo de pozos de sondajes en la Cuenca de Magallanes y pertenecientes al denominado Complejo ígneo y Metamór-fico de Tierra [...] del Fuego. En tres de las muestras fueron calculadas edades del Cámbrico Temprano (523±7 Ma, 522±6 Ma y 538±6 Ma), interpretadas como edades de cristalización 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. Abstract in english Five new SHRTMP U-Pb zircon ages are reported for gneisses and foliated plutonic rocks belonging to the Tierra del Fuego igneous and metamorphic basement complex (TFIMC), obtained from the bottom of borehole cores through the Magallanes Basin. Three of the samples yielded weighted mean 206Pb/238U ag [...] es (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.

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

 
 
 
 
121

Salt movements in the Northeast German Basin and its relation to major post-Permian tectonic phases—results from 3D structural modelling, backstripping and reflection seismic data  

Science.gov (United States)

The NW-SE-striking Northeast German Basin (NEGB) forms part of the Southern Permian Basin and contains up to 8 km of Permian to Cenozoic deposits. During its polyphase evolution, mobilization of the Zechstein salt layer resulted in a complex structural configuration with thin-skinned deformation in the basin and thick-skinned deformation at the basin margins. We investigated the role of salt as a decoupling horizon between its substratum and its cover during the Mesozoic deformation by integration of 3D structural modelling, backstripping and seismic interpretation. Our results suggest that periods of Mesozoic salt movement correlate temporally with changes of the regional stress field structures. Post-depositional salt mobilisation was weakest in the area of highest initial salt thickness and thickest overburden. This also indicates that regional tectonics is responsible for the initiation of salt movements rather than stratigraphic density inversion. Salt movement mainly took place in post-Muschelkalk times. The onset of salt diapirism with the formation of N-S-oriented rim synclines in Late Triassic was synchronous with the development of the NNE-SSW-striking Rheinsberg Trough due to regional E-W extension. In the Middle and Late Jurassic, uplift affected the northern part of the basin and may have induced south-directed gravity gliding in the salt layer. In the southern part, deposition continued in the Early Cretaceous. However, rotation of salt rim synclines axes to NW-SE as well as accelerated rim syncline subsidence near the NW-SE-striking Gardelegen Fault at the southern basin margin indicates a change from E-W extension to a tectonic regime favoring the activation of NW-SE-oriented structural elements. During the Late Cretaceous-Earliest Cenozoic, diapirism was associated with regional N-S compression and progressed further north and west. The Mesozoic interval was folded with the formation of WNW-trending salt-cored anticlines parallel to inversion structures and to differentially uplifted blocks. Late Cretaceous-Early Cenozoic compression caused partial inversion of older rim synclines and reverse reactivation of some Late Triassic to Jurassic normal faults in the salt cover. Subsequent uplift and erosion affected the pre-Cenozoic layers in the entire basin. In the Cenozoic, a last phase of salt tectonic deformation was associated with regional subsidence of the basin. Diapirism of the maturest pre-Cenozoic salt structures continued with some Cenozoic rim synclines overstepping older structures. The difference between the structural wavelength of the tighter folded Mesozoic interval and the wider Cenozoic structures indicates different tectonic regimes in Late Cretaceous and Cenozoic. We suggest that horizontal strain propagation in the brittle salt cover was accommodated by viscous flow in the decoupling salt layer and thus salt motion passively balanced Late Triassic extension as well as parts of Late Cretaceous-Early Tertiary compression.

Scheck, Magdalena; Bayer, Ulf; Lewerenz, Björn

2003-01-01

122

A first record of late Middle Permian actinopterygian fish from Anatolia, Turkey  

Science.gov (United States)

The Middle-Upper Permian of the Gomaniibrik Formation, of the Tanin Group, in south-east Anatolia, close to the Iraq border, yielded moderately preserved fish remains. Two species, Palaeoniscum freieslebeni and Pygopterus cf. nielseni, known so far only from the Upper Permian deposits of the Zechstein Basin in western Central Europe, were recognised. This late Middle Permian Anatolian record significantly widens the geographical range of these actinopterygians into the equatorial Palaeotethys Realm.

Ho?gör, Izzet; Štamberg, Stanislav

2014-06-01

123

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

124

Spectral gamma-ray signature of fluvial deposits: a case study from the Late Permian Rio do Rasto Formation, Paraná Basin, Brazil  

Directory of Open Access Journals (Sweden)

Full Text Available 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.

Guilherme Arruda Sowek

2013-09-01

125

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

126

Problems and challenges in detection of pre-Mesozoic maar volcanoes: example from the Principálek Volcano in the Permian Krkonoše Piedmont Basin  

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Full Text Available The Permian pyroclastic deposits on the Principálek Hill SW of Vrchlabí (Czech Republic were investigated by means of geological mapping and geophysics. The pyroclastic rocks are exposed in several small coherent outcrops, yet many interpretations are based on debris. The preserved textures enable reconstruction of eruptive styles. The volcanism started with phreatomagmatic eruptions documented by the fine-grained tuff with accretionary lapilli at the base. Subsequently, the activity changed to phreato-Strombolian/Surtseyan producing lapilli-tuffs and lapillistones. These events were followed by a Strombolian phase as evidenced by ill-sorted scoriaceous tuff-breccias with volcanic bombs. The uppermost unit consists of welded lava agglutinates and basaltic lavas suggesting a Hawaiian style of eruption. One of the basaltic feeder necks is exposed in a small abandoned quarry.Geophysical surveys were carried out over the extent of pyroclastic deposits. These included gravimetry, magnetometry, and DC resistivity tomography. The magnetic data indicate the occurrence of basaltic dykes in the central part of the pyroclastic deposits. The DC tomography confirms the presence of dykes, enables estimation of the pyroclastic deposits thickness, and provides evidence for the size and position of the maar-diatreme. Gravity data yield an insignificant low associated with the diatreme, which is likely a product of low rock-density contrast between the diatreme and country rocks. We argue that this is due to short time gap between sedimentation and volcanic activity and also related to conjoint burial and diagenetic history of the diatreme and the surrounding country rocks.

Valenta J

2014-07-01

127

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

128

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 Per...

Artur Chahud; Setembrino Petri

2010-01-01

129

Geoscience/engineering characterization of the interwell environment in carbonate reservoirs based on outcrop analogs, Permian Basin, West Texas and New Mexico--waterflood performance analysis for the South Cowden Grayburg Reservoir, Ector County, Texas. Final report  

Energy Technology Data Exchange (ETDEWEB)

A reservoir engineering study was conducted of waterflood performance in the South Cowden field, an Upper Permian Grayburg reservoir on the Central Basin Platform in West Texas. The study was undertaken to understand the historically poor waterflood performance, evaluate three techniques for incorporating petrophysical measurements and geological interpretation into heterogeneous reservoir models, and identify issues in heterogeneity modeling and fluid-flow scaleup that require further research. The approach included analysis of relative permeability data, analysis of injection and production data, heterogeneity modeling, and waterflood simulation. The poor South Cowden waterflood recovery is due, in part, to completion of wells in only the top half of the formation. Recompletion of wells through the entire formation is estimated to improve recovery in ten years by 6 percent of the original oil in place in some areas of the field. A direct three-dimensional stochastic approach to heterogeneity modeling produced the best fit to waterflood performance and injectivity, but a more conventional model based on smooth mapping of layer-averaged properties was almost as good. The results reaffirm the importance of large-scale heterogeneities in waterflood modeling but demonstrate only a slight advantage for stochastic modeling at this scale. All the flow simulations required a reduction to the measured whole-core k{sub v}/k{sub h} to explain waterflood behavior, suggesting the presence of barriers to vertical flow not explicitly accounted for in any of the heterogeneity models. They also required modifications to the measured steady-state relative permeabilities, suggesting the importance of small-scale heterogeneities and scaleup. Vertical flow barriers, small-scale heterogeneity modeling, and relative permeability scaleup require additional research for waterflood performance prediction in reservoirs like South Cowden.

Jennings, J.W. Jr.

1997-05-01

130

Influence of tectonics on Permian coal-rank patterns in Australia  

Energy Technology Data Exchange (ETDEWEB)

Coal in the Australian Permian basins is dominantly subbituminous coal to medium-volatile bituminous coal. The subbituminous coal and higher-rank bituminous coals are generally the result of burial diagenesis. Localized low-volatile bituminous coal to anthracite is commonly associated with igneous activity. Extensive zones of high-rank coal in the eastern part of the Bowen Basin are due to uplift of deeply buried coal-measure sequences during Late Permian and Triassic tectonism. High-rank coals in the Sydney Basin are due to uplift of deeply buried Permian rocks preceding sea-floor spreading in the Tasman Sea during the Late Cretaceous and early Tertiary although this conclusion is controversial. Localized semianthracite and anthracite at depths greater than 2,500 m in the Cooper Basin were formed either by enhanced heat flow from radiogenic basement granites or by vertical movement of hot fluids through the fractured granitic bodies during the Tertiary. Permian coals in the Pedirka and Arckaringa Basins in the center of the continent, and the Perth, Carnarvon, Canning, Bonaparte and Officer Basins in the west are generally low in rank due to either shallow depths of burial or slight heat flow, or both. The Fitzroy Trough of the Canning Basin is an exception; there significant tectonic activity has occurred since the Permian. 67 refs., 10 figs., 1 tab.

Middleton, M.F.; Hunt, J.W. (Geological Survey of Western Australia, Perth)

1989-07-01

131

Sedimentary Response to Arc-Continent Collision, Permian, Southern Mongolia  

Science.gov (United States)

The Eurasian Tien Shan-Yin Shan suture is a ~3000 km-long boundary between Paleozoic arc and accretionary complexes (the Altaids) and Precambrian microcontinental blocks (Tarim and North China block). Stratigraphic data are presented from localities in southern Mongolia spanning more than 800 km along the northern margin of the suture. Facies descriptions, climatic indicators, sandstone provenance, and paleocurrent data help reconstruct Permian basin evolution during and following arc-continent collision, and results are integrated with previously published data to create a preliminary regional synthesis. Upper Permian strata of southern Mongolia comprise fluvial successions in the southwest, and marine turbidite deposits in the southeast. Floral assemblages show mixing of Siberian craton and North China block communities, indicating their close proximity to Mongolia by Permian time. There is a rapid transition from humid environments in the Late Permian to more arid conditions in the Early Triassic, which corresponds to the global Permian-Triassic boundary event, but may also reflect more local driving mechanisms such as rain shadow effects. Permian sandstones from Mongolia have undissected to dissected arc provenance, with little input from continental or recycled orogen sources. Timing of the nonmarine-marine facies transition and cessation of arc magmatism broadly supports earlier collision along the western part of the suture zone than the eastern part (e.g., Late Carboniferous-Late Permian). However when regional geologic constraints are integrated, a more complex model involving differential rotation of Tarim and the North China block is preferred. Late Paleozoic rocks of southern Mongolia have been subsequently dismembered along Mesozoic-Cenozoic strike-slip faults, and thus also represent the long-term record of intracontinental deformation within accreted, heterogeneous crust.

Johnson, C.; Amory, J.; Zinniker, D.; Lamb, M.; Graham, S.; Affolter, M.; Badarch, G.

2007-12-01

132

Middle-Late Permian mass extinction on land  

Energy Technology Data Exchange (ETDEWEB)

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

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

2006-11-15

133

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

134

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

Science.gov (United States)

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

Clausen, Ole R.; Andresen, Katrine J.; Rasmussen, Jens A.

2013-04-01

135

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

136

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

137

Residual basins  

International Nuclear Information System (INIS)

Exploration for uranium carried out over a major portion of the Rio Grande do Sul Shield has revealed a number of small residual basins developed along glacially eroded channels of pre-Permian age. Mineralization of uranium occurs in two distinct sedimentary units. The lower unit consists of rhythmites overlain by a sequence of black shales, siltstones and coal seams, while the upper one is dominated by sandstones of probable fluvial origin. (Author)

138

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

139

Stratigraphy and tectonics of Permo-Triassic basins in the Netherlands and surrounding areas  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This thesis addresses different aspects of the geological development during the Permian and Triassic (300 to 200 Ma) of the Netherlands and surrounding areas. The study area encompasses the Southern Permian Basin (SPB), a large intracratonic basin stretched out from the United Kingdom in the west to Lithuania in the east. This study revealed that, rather than one basin, the SPB actually comprised three basins, separated by subtle swells. The basins each originated differently with specific ...

Geluk, M. C.

2005-01-01

140

Permian geology of Gondwana countries: An overview  

Energy Technology Data Exchange (ETDEWEB)

Earliest Permian sequences of Antarctica, southern and east-central Africa, the southern part of the Arabian Peninsula, Pakistan, peninsular and Himalayan India, Tibet, western and eastern Australia, New Zealand, and South America are all characterized by glacial deposits and cold-water marine faunas. In the course of the Permian, considerable faunal (and floral) and climatic divergence occurred. Although folding is not necessarily present, the effects of the strong compressive tectonic phase (Hunter-Bowen Orogenic Folding Phase of Dickins) beginning in the mid-Permian (traditional two-fold subdivision) and of acidic and intermediate volcano-magmatic activity are apparent in all these regions as in other parts of the world. The progressive continentality of the Upper Permian (worldwide regression) culminates at the Permian-Triassic (Changxingian-Griesbachian) boundary.

Dickins, J.M. (Australian Bureau of Mineral Resources, Canberra (Australia))

1992-10-01

 
 
 
 
141

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

DEFF Research Database (Denmark)

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

Clausen, O.R.; Andresen, Katrine Juul

142

Permian geodynamic setting of Northeast China and adjacent regions: closure of the Paleo-Asian Ocean and subduction of the Paleo-Pacific Plate  

Science.gov (United States)

Northeast China and adjacent regions are located in the central East Asian continent and consist tectonically of both the Paleo-Asian and Paleo-Pacific orogens between the Siberian platform and Sino-Korean (North China) block. This paper discusses some hotly-debated issues concerning the Permian geodynamic setting of these regions, based on a comprehensive analysis of available geological, geochemical, paleobiogeographical and paleomagnetic data. Spatial and temporal distribution of ophiolites and associated continental marginal sequences, Permian sedimentary sequences, spatial distribution and geochemistry of Permian magmatic rocks, and the evolution of paleobiogeographical realms imply: (1) that the Permian marine basins in northeast China and adjacent regions include remnants of the Paleo-Asian Ocean in southeastern Inner Mongolia and central Jilin Province, and active continental margins of the Paleo-Pacific Ocean; (2) that the suture between the Siberian and Sino-Korean paleoplates was finally emplaced in the Permian and is located in areas from Suolunshan (Solonker) eastwards through regions north to the Xar Moron river in southeastern Inner Mongolia, and then central Jilin province to the Yanji area; and (3) that the Permian crustal evolution of northeast China and adjacent regions, as well as parts of the Siberian paleoplate, was influenced by subduction of the Paleo-Pacific oceanic plate. Finally, the Permian tectonic framework and paleogeography of northeast China and adjacent regions in central East Asia are discussed briefly, and Early and Late Permian palinspastic reconstruction maps are provided.

Li, J.-Y.

2006-03-01

143

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

144

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

145

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

146

A potential biomarker for the Permian Triassic ecological crisis  

Science.gov (United States)

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

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

2005-07-01

147

Dalhart's only Permian field gets best oil well  

International Nuclear Information System (INIS)

This paper reports that activity is picking up in Proctor Ranch oil field in the northwestern Texas panhandle, the only Permian producing field in the lightly drilled Dalhart basin. During the last 2 1/2 months, the field has a new operator and a new producing well, the best of five drilled since discovery in 1990. Corlena Oil Co., Amarillo, acquired the field from McKinney Oil Co. in May and tested its first well in early July. The 1-64 Proctor, 18 miles west of Channing, pumped at rates as high as 178 bd of oil and 6 b/d of water from Permian Wolfcamp dolomite perforations at 4,016-29 ft. Corlena plans to drill another well south of the field soon. The lease requires that the next well be spudded by early November. The field appears to be combination structural-stratigraphic trap in which the dolomite pinches out against the Bravo Domes-Oldham nose to the west

148

Billions of barrels of potential Permian oil starts race for carbon dioxide in the Rockies  

Energy Technology Data Exchange (ETDEWEB)

Major producers in the Permian Basin are jockeying for position in the race for a different type of natural gas--carbon dioxide. The purse for the winners may be billions of barrels of additional oil recovery from the Permian Basin fields. The track is leading the competitors to the north, through New Mexico, Colorado, and Utah, where stratigraphic and structural accumulations of carbon dioxide, nearly 100% pure in some places, are known to exist. Land positions are being blocked up, many wells have been drilled and more are underway. Potential tertiary recovery projects in the Permian Basin are the reason for all the excitement. Some engineers feel the carbon dioxide miscible flood is the best, perhaps the only way in this region, to economically recover billions of barrels of remaining oil. Chevron led the field, initially, with its carbon dioxide miscible flood at Sacroc. The first major tertiary project of its type, the experiment in Scurry County's Kelly-Snyder field, has been termed a success. The operator says some 35,000 bpd of tertiary oil is being recovered from the 50,000-acre project.

Hart, D.

1976-06-01

149

Sedimentary evolution of Rio do Rastro formation (permian-triassic of the Parana Basin) at central south portion of Santa Catarina State, Brazil; Evolucao sedimentar da Formacao Rio do Rastro (Permo-Triassico da Bacia do Parana) na porcao centro sul do estado de Santa Catarina, Brasil  

Energy Technology Data Exchange (ETDEWEB)

Between the Late Carboniferous and the Early Triassic, the south portion of the Gondwana Supercontinent witnessed the development of intracratonic basins related with the coeval Sanrafaelic Orogeny. The continuous subsidence and consequent generation accommodation space resulted in the formation of a large confined water body and the accumulation of a transgressive regressive sequence between the Late Permian and the Early Triassic. The progradational nature of the upper portion of this sequence, represented by de Rio do Rasto e Piramboia formations, culminated with the complete filling of the water body. In the south-eastern portion of Santa Catarina State (Southern Brazil), the Rio do Rasto Formation overlies the Teresina formation and is overlain by the Piramboia formation, both contacts being characterized by lithological transition. The lower portion of the Rio do Rasto Formation is characterized by architectural elements deposited in offshore environments subject to storm action. A marked change of the color of the pelitic facies, from gray to red and purple occurs at the top of the unit. At this stratigraphic level, there is also a predominance of deltaic and eolian architectural elements. The intercalation of near shore and offshore architectural elements can be explained by the strong auto cyclic character expected in deltaic depositional systems and by the variation of relative rates of base-level rise. The occurrence of eolian architectural elements interbedded with subaquatically deposited sediments on the second third of the unit can be considered an evidence of continentalization to the top, materialized as the transition to the Piramboia desert system. (author)

Warren, Lucas Verissimo; Roldan, Luis Fernando; Steiner, Samar dos Santos; Chamani, Marlei Antonio Carrari [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Geociencias. Programa de Pos Graduacao em Geoquimica e Geotectonica]. E-mail: lvwarren@yahoo.com; Almeida, Renato Paes de; Hachiro, Jorge; Machado, Romulo [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Geociencias. Dept. de Geologia Sedimentar e Ambiental

2008-06-15

150

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.

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

2010-03-30

151

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

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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

152

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

153

Paleoenvironment of the Permian rocks: a comparison between central and eastern Alborz, Iran  

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The succession of Permian rocks in Alborz region is composed of siliciclastic and carbonate facies. All of the sediments were deposited in the Paleotethyan passive continental margin but they show different facies architecture and paleoenvironmental condition in various parts of the region. This study, as part of a wider project, has investigated sedimentary facies and paleoenvironment of the Permian rocks in central and eastern Alborz. The Permian rocks in central Alborz are dominated by siliciclastic facies (Doroud Formation) in the lower, and carbonate facies (Ruteh Formation) in the upper half. Field studies and laboratory measurements resulted in recognition of 4 terrigenous and 13 carbonate facies in the succession. A siliciclastic shallow marine system was determined as depositional environment of the terrigenous facies. A homoclinal carbonate ramp, with scattered patch reefs, was determined as depositional environment of the carbonate facies. Dasycladacean green algae, ancestral red algae, hermatypic corals and bryozoans were the major bioconstructors of the ramp. The abundance of skeletal shoals respect to ooidal shoals in the ramp margin was high. The Permian rocks in eastern Alborz are dominated by mixed siliciclastic-carbonate facies (Ruteh Formation) in the lower, and siliciclastic facies (Nesen Formation) in the upper half. The studies resulted in recognition of 5 terrigenous and 6 carbonate facies in the succession. A mixed siliciclastic-carbonate shelf with high sediment influx was determined as depositional environment of the mixed siliciclastic-carbonate facies. Occurrence of the small patch reefs with high coral diversity in this mixed shelf indicates normal marine (hyposaline) condition. Upper terrigenous facies were deposited in fluvial-flood plain system. Difference in paleoclimate and tectonic activity of two sub-basins seems to be the major cause of the differences between the Permian facies in central and eastern Alborz.

Lankarani, M.; Amini, A.; Mosadegh, H.

2009-04-01

154

The Jurassic of Denmark and Greenland: Late Triassic – Jurassic development of the Danish Basin and the Fennoscandian Border Zone, southern Scandinavia  

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The continental to marine Upper Triassic – Jurassic succession of the Danish Basin and the Fennoscandian Border Zone is interpreted within a sequence stratigraphic framework, and the evolution of the depositional basin is discussed. The intracratonic Permian–Cenozoic Danish Basin was formed by Late Carboniferous – Early Permian crustal extension followed by subsidence governed primarily by thermal cooling and local faulting. The basin is separated from thestable Precambrian Baltic Shiel...

Nielsen, Lars Henrik

2003-01-01

155

Middle Permian plume-related volcanism of the Hawasina Nappes (Oman) and the Neo-Tethys opening  

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According to palinspastic reconstructions, the Neo-Tethys opening took place during the Permian between the Cimmerian fragments in the north and the Indian-Arabian margin in the south. Igneous remnants of this opening are found nowdays in Oman where they belong mostly to the Hawasina nappes and consist of pillowed mafic flows interbedded with Middle Permian sediments. Three groups of rocks have been distinguished among the Middle Permian rocks from Oman which were emplaced either on the Arabian submerged platform or the neighbouring Hawasina basin. Group 1 is tholeiitic and characterized by low TiO_2 (Hawasina Nappes. Group 3 trace element chemistry is similar to that of Group 2. Thus, whatever the geological setting of the Oman Permian lavas, they belong to tholeiitic and alkalic magmas but differ by their Nd isotopic composition. A majority of the magmas emplaced in the Hawasina basin are characterized by ?Nd that fall within the range of OIB. In contrast, most of the volcanic rocks emplaced on the submerged Arabian platform and few samples from the Hawasina nappes have low to negative ?Ndi suggesting a contribution of continental crust.

Lapierre, H.; Samper, A.; Bosch, D.; Maury, R. C.; Cotten, J.; Béchennec, F.; Brunet, P.; Caroff, J.; Keller, F.; Demant, A.

2003-04-01

156

Inorganic chemistry, petrography and palaeobotany of Permian coals in the Prince Charles Mountains, East Antarctica  

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Sampled outcrops of Permian coal seams of the Bainmedart Coal Measures in the Lambert Graben, eastern Antarctica, have been analysed for their proximates, ultimates, ash constituents and trace elements. A similar series of samples has been analysed for their principle maceral and microlithotype components and vitrinite reflectance. The coals are sub-bituminous to high volatile bituminous in rank; maturity increases markedly in southern exposures around Radok Lake where the oldest part of the succession is exposed and some strata have been intruded by mafic dykes and ultramafic sills. The coal ash is mostly silica and aluminium oxides, indicating that the mineral ash component is mostly quartz and various clay minerals. The ratio of silica to aluminium oxides appears to increase in an upward stratigraphic direction. The coal macerals include a relatively high liptinite content (mainly sporinite) that is significantly higher than for typical Gondwana coals. Greater degrees of weathering within the floodbasin/peat mire environments associated with climatic drying towards the end of the Permian might account for both preferential sporopollenin preservation and increased silica:aluminium oxide ratios up-section. Correlation of the coal maceral components to adjacent peninsula India coals indicates the closest comparative coals of similar age and rank occur within the Godavari Basin, rather then the Mahanadi Basin, which is traditionally interpreted to have been contiguous with the Lambert Graben before Gondwanan breakup. The petrological characteristics suggest that either previous interpretations of Palaeozoic basin alignments between Antarctica and India are incorrect, or that environmental settings and post-Permian burial histories of these basins were strongly independent of their tectonic juxtaposition. A permineralized peat bed within the succession reveals that the coals predominantly comprise wood- and leaf-rich debris derived from low-diversity forest-mire communities dominated by glossopterid and noeggerathiopsid gymnosperms. ?? 2005 Elsevier B.V. All rights reserved.

Holdgate, G.R.; McLoughlin, S.; Drinnan, A.N.; Finkelman, R.B.; Willett, J.C.; Chiehowsky, L.A.

2005-01-01

157

A record of Permian subaqueous vent activity in southeastern Brazil.  

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The remarkable occurrence of more than 4,500 conical siliceous mounds in an area of less than 1.5 square kilometres has been reported in the Paraná basin, near Anhembi, São Paulo, in southeastern Brazil. These structures, which are up to two metres high, are thought to have been formed at the margin of a very shallow, broad but waning internal sea, and it was originally suggested that they are stromatolites. Yet their restricted occurrence, unusual abundance and nearly pure siliceous composition have never been satisfactorily explained by this hypothesis. Here we report field and laboratory observations on their shape, construction, composition and mineralogy. On the basis of our data we suggest that the conical mounds are the result of subaqueous Late Permian vent activity in southwestern Gondwana. The present siliceous cone field differs considerably from other Palaeozoic siliceous hot spring deposits, such as those at Rhynie, Scotland, and the Drummond basin, Australia, and therefore represents an unusual occurrence of vent activity. PMID:16281032

Yamamoto, Jorge Kazuo; Fairchild, Thomas Rich; Boggiani, Paulo Cesar; Montanheiro, Tarcísio Jose; de Araújo, Carlos César; Kiyohara, Pedro Kunihiko; de Matos, Sergio Luis Fabris; Soares, Paulo César

2005-11-10

158

High-resolution stable carbon isotope record of the Permian to earliest Triassic from East Greenland  

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The Late Permian and Early Triassic organic carbon isotope records show global major excursions probably triggered by episodic volcanic degasing of the Siberian Large Igneous Province. Important and rapid fluctuations of the global carbon cycle are also reflected in the biosphere. The geological record seems to comprise several major floral and marine faunal turnovers indicating short-lived biotic recoveries. In northwest Pangea, the active Early Triassic Greenland - Norway rifting system led to the accommodation of thick sedimentary sequences. This basin has a great potential for detailed studies of regional and global biotic and climatic changes with high temporal resolution during this critical interval in Earth's history. The western part of this basin is exposed in north-eastern Greenland and is represented by a succession of deltaic sediments organized in a general regressive trend ranging throughout the Griesbachian and the onset of the Dienerian. On the eastern side of the basin the succession has been drilled off the Norwegian coast. On Hold with Hope (East Greenland, 74°N) up to ca. 800m thick sections of the ammonoid-bearing Early Triassic Wordie Creek Formation have been logged and sampled. Here we present a high-resolution organic carbon isotope record and preliminary palynofacies data of a 500m thick composite section ranging from the Permian into the earliest Triassic. The organic carbon isotope record is closely comparable to the coeval section from the Trøndelag platform in Mid-Norway. The two records show a first major negative shift (ca. -6‰) representing the unconformity between the Ravnefjeld and the Wordie Creek formations, regionally known as the lithological Permian-Triassic boundary. Higher up, a second negative shift of ca. -4‰ correlates with the carbon shift associated with the GSSP Permian-Triassic boundary as defined at Meishan (China), represented by carbon isotope values around -30‰. This negative shift is followed by a steady positive trend, which is interrupted by two striking events, (a) a positive shift reaching values of ca. -22‰, comparable to the values of the Permian Ravnefjeld Formation, and (b) another negative shift of ca. -7‰ bringing the carbon record back to values around -31‰. Our data from north-eastern Greenland indicate multiple and major events recorded by the carbon cycle within less than a million years at the onset of the Triassic.

Sanson Barrera, Anna; Hochuli, Peter A.; Bucher, Hugo; Meier, Maximiliano; Schneebeli Hermann, Elke; Weissert, Helmut; Bernasconi, Stefano M.

2013-04-01

159

Dissolution of Evaporites in and around the Delaware Basin, Southeastern New Mexico and West Texas.  

Science.gov (United States)

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 tilt...

S. J. Lambert

1983-01-01

160

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.

Iannuzzi Roberto

2004-01-01

 
 
 
 
161

Clarification and changes in Permian stratigraphic nomenclature in Kansas  

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This paper outlines Permian nomenclature changes to Zeller (1968) that have been adopted by the Kansas Geological Survey. The Permian System/ Period, Cisuralian Series/Epoch, and Asselian Stage/Age are established at the base of the Bennett Shale Member of the Red Eagle Limestone. Series/epoch names Wolfcampian, Leonardian, and Guadalupian are retained and usage of Gearyan, Cimarronian, and Custerian is abandoned. The repositioned Carboniferous-Permian boundary divides the Council Grove Group into Carboniferous (Upper Pennsylvanian Series/Epoch; Virgilian Stage/Age) and Permian (Wolfcampian Series Epoch) segments.

Sawin, R. S.; Franseen, E. K.; West, R. R.; Ludvigson, G. A.; Watney, W. L.

2008-01-01

162

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

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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

163

Recrystallized microbial trace fossils from metamorphosed Permian basalt, southwestern Japan  

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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 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

164

The Buday'ah Formation, Sultanate of Oman: A Middle Permian to Early Triassic oceanic record of the Neotethys and the late Induan microsphere bloom  

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The Middle Permian to Lower Triassic Buday'ah section, exposed in the Oman Mountains, is the first deep-sea section to be described in the Neotethys. The oceanic sediments were deposited along the southern Tethys margin in the newly formed Hawasina Basin. It is one of the few places where true Tethyan Permian radiolarites are exposed that allow the documentation of CCD evolution through time. The succession begins as oceanic crust pillow basalt with red ammonoid-rich pelagic limestone occurring both above and within inter-pillow cavities; the new occurrence of Clarkina postbitteri hongshuiensis indicates a late Capitanian age for the carbonate. The sharp change to overlying late Capitanian to Changhsingian radiolarite reflects rapid subsidence about 10 Myrs after initial continental breakup that resulted in the formation of the Neotethys Ocean. New conodonts indicate that the Permian-Triassic boundary succession occurs in the first platy lime mudstone beds above a Changhsingian siliceous to calcareous shale unit. The platy lime mudstone beds include an Upper Griesbachian bloom of calcite filled spheres (radiolarians?) that marks a potential world-wide event. New conodonts indicate an early Olenekian age for overlying grey papery limestone that are devoid of both macrofossils and trace fossils indicating that recovery from the Late Permian extinction has not yet progressed within this deep-water environment. ?13C org, isotope values have not been disturbed and they show a negative shift just below the Permian-Triassic transition and a second one at the parvus zone level above. The Buday'ah succession may represent the most distal and probably deepest Permian and Lower Triassic depositional sequence within the basin.

Baud, Aymon; Richoz, Sylvain; Beauchamp, Benoit; Cordey, Fabrice; Grasby, Stephen; Henderson, Charles M.; Krystyn, Leopold; Nicora, Alda

2012-01-01

165

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

166

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

167

The Donets Basin (Ukraine/Russia). Coalification and thermal history  

Energy Technology Data Exchange (ETDEWEB)

The Donets Basin (Donbas) is one of the major late Paleozoic coal basins in the world. The Donbas Foldbelt is an inverted part of the Donets Basin characterized by WNW-ESE-trending folds and faults. The age of basin inversion is under discussion. Large parts of the Donets Basin host anthracite and meta-anthracite. Low-rank coals are restricted to the western and northern basin margins. Vitrinite reflectance patterns along the Gorlovka Anticline indicate syn-deformational coalification. Vitrinite reflectance isolines are displaced along thrusts, clear evidence that main coalification predates late faulting. 1-D and 2-D numerical models were applied to elucidate the factors that control coalification in the western Donets Basin (Krasnoarmeisk Monocline, Kalmius-Torets Depression, South Syncline). The models indicate that the depth of the seams and the heat flow during maximum (Permian) burial are the most important parameters. The thickness of late Carboniferous and Permian rocks increased from the southwestern basin margin towards the basin center. Permian erosion along the Krasnoarmeisk Monocline and in the Kalmius-Torets Depression was on the order of 2-3 km. More rocks were eroded southeast of the Donetsk-Kadievka Fault Zone (4-5 km). Heat flow during maximum burial was in the range of 40-75 mW/m{sup 2}. Heat flow in the Krasnoarmeisk Monocline and the Kalmius-Torets Depression increased in a northeastward direction from 40 to 55 mW/m{sup 2}. Heat flow at the eastern edge of the Kalmius-Torets Depression and in the South Syncline was in the range of 60-75 mW/m{sup 2} and increased towards the southeast. The resulting coalification pattern in this area was overprinted by thermal events in the northern Krasnoarmeisk Monocline and the South Syncline. These are probably related to (Permian?) magmatic intrusions. Coked coal occurs at the contact to presumed Permian sills and dikes southwest of Donetsk.

Sachsenhofer, R.F.; Rainer, T.; Shymanovskyy, V.A. [Institut fuer Geowissenschaften, Montanuniversitaet Leoben, Peter-Tunner-Strasse 5, A-8700 Leoben (Austria); Privalov, V.A. [Donetsk State Technical University, Artem str., UA-84000 Donetsk (Ukraine); Zhykalyak, M.V. [Donetsk State Regional Geological Survey, Sybirtseva str. 17, UA-84500 Artemovsk (Ukraine); Bueker, C. [Institute of Geology, and Geochemistry of Petroleum and Coal, Aachen (Germany); Panova, E.A. [UkrNIMI, Tchelyuskintsev str. 291, UA-83121 Donetsk (Ukraine); Stephenson, R. [Research School of Sedimentary Geology, Vrije Universiteit, De Boelelaan 1085, 1081 HV Amsterdam (Netherlands)

2002-02-01

168

The carbon and sulfur cycles and atmospheric oxygen from middle Permian to middle Triassic  

Science.gov (United States)

The results of a theoretical isotope mass balance model are presented for the time dependence of burial and weathering-plus-degassing fluxes within the combined long-term carbon and sulfur cycles. Averaged data for oceanic ? 13C and ? 34S were entered for every million years from 270 to 240 Ma (middle Permian to middle Triassic) to study general trends across the Permian-Triassic boundary. Results show a drop in the rate of global organic matter burial during the late Permian and a predominance of low values during the early-to-middle Triassic. This overall decrease with time is ascribed mainly to epochs of conversion of high biomass forests to low biomass herbaceous vegetation resulting in a decrease in the production of terrestrially derived organic debris. Additional contributions to lessened terrestrial carbon burial were increased aridity and a drop in sea level during the late Permian which led to smaller areas of low-lying coastal wetlands suitable for coal and peat deposition. Mirroring the drop in organic matter deposition was an increase in the burial of sedimentary pyrite, and a dramatic increase in the calculated global mean ratio of pyrite-S to organic-C. High S/C values resulted from an increase of deposition in marine euxinic basins combined with a decrease in the burial of low-pyrite associated terrestrial organic matter. The prediction of increased oceanic anoxia during the late Permian and early Triassic agrees with independent studies of the composition of sedimentary rocks. Weathering plus burial fluxes for organic carbon and pyrite sulfur were used to calculate changes in atmospheric oxygen. The striking result is a continuous drop in O 2 concentration from ˜30% to ˜13% over a twenty million year period. This drop was brought about mainly by a decrease in the burial of terrestrially derived organic matter. but with a possible contribution from the weathering of older organic matter on land. It must have exerted a considerable influence on animal evolution because of the role of O 2 in respiration. Some examples are the extinction of many vertebrates, loss of giant insects and amphibians, and the restriction of animals to low elevations. It is concluded that the extinction of plants may have contributed to the extinction of animals.

Berner, Robert A.

2005-07-01

169

Integrated Salt Basin Evaluation  

Science.gov (United States)

Salt tectonics plays a major role in the development of many sedimentary basins. Basins containing salt thus frequently display a complex geodynamic evolution characterized by several phases of halokinesis and associated sedimentation. One classic area of salt tectonics is the Central European Basin System (CEBS). Here, the mobile Permian Zechstein salt formed a large number of salt structures such as anticlines, diapirs, pillows, sheets, stocks, and walls during an extended period of salt tectonic activity in Mesozoic and Cenozoic times. Major changes in sedimentation patterns and structural regimes are associated and common in this setting. Increasingly complex subsurface evaluation therefore requires an approach to study salt basins including analogue and numerical models, field studies and laboratory studies which combine seismic, structural and sedimentary studies with analysis of rheological properties, and geomechanic modelling. This concept can be demonstrated using case studies from Permian Salt Basins in Europe and the Late Neoproterozoic to Early Cambrian South Oman Salt Basin. There salt-influenced sedimentary responses to renewed phases of tectonism can be clearly discerned from detailed sequence analysis based on seismic and log data combined with retrodeformation modelling studies. High quality 3-D seismic data integrated with structural modelling improves the definition of the internal dynamics of salt structures and associated sediment architecture in salt-controlled sequences. Paleo-caprocks inside the diapirs point to long phases of dissolution. Salt wedges formed by extrusion and lateral flow of salt glaciers during periods of diapir emergence and reduced sediment accumulation can be accurately modelled. Although salt is widely regarded as a perfect seal, it can become permeable for one- or two-phase fluids under certain conditions of fluid pressure, temperature and deviatoric stress. The fluid pathways can be either along zones of diffuse grain boundary dilatancy, or along open fractures, depending on the fluid overpressure and deviatoric stress.

Kukla, P. A.

2012-04-01

170

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

171

Supersequence and composite sequence carbonate platform growth: Permian and Triassic outcrop data of the Arabian platform and Neo-Tethys  

Science.gov (United States)

Permian and Triassic carbonate platforms of the Arabian Peninsula (Gondwana) and seamounts of the Neo-Tethys (Hawasina and Batain basins) are characterized by distinctive supersequences (second order, duration 5-20 million years, my) and composite sequences (third order, duration 0.5-5 my). The presented sequence stratigraphic framework will be compared with existing sea level curves to discuss the validity of different regional oscillations during the dispersal of Pangea. The carbonate succession of the Haushi and Akhdar Groups of the Arabian platform is composed of four Permian (P1-P4) and four Triassic supersequences (Tr1-Tr4). Isolated platforms of the Hawasina and Batain basins comprise two Permian supersequences and one Triassic supersequence. In contrast to the continuous development of the Arabian shield, carbonate platform growth of the seamounts was restricted to the Guadalupian-Lopingian and to the Middle-Upper Triassic, and ceased after drowning events. Composite sequences exhibit a well-developed stacking pattern during the Guadalupian-Lopingian (Saiq Formation). Lowstand systems tracts (LSTs) occur during the Cisuralian (Gharif Formation, Haushi Group) and Triassic (Mahil Formation, Akhdar Group). Open-marine depositional environments prevail during transgressive systems tracts (TSTs) with diverse biota including rugose and scleractinian corals, chaetetids, bryozoans, and crinoids. Highstand system tracts (HSTs) exhibit a twofold pattern: During the transgressive phase of supersequences, composite sequence highstands are dominated by reef or level-bottom communities with corals. Cyclic platform deposits or monotonous mud- and wackestone accumulated during the turnaround or late second-order highstand of a supersequence. Correlation of maximum flooding surfaces with published data suggests that supersequences P1, P2, and Tr4 can be traced across the Arabian platform into the Neo-Tethys basins, while supersequences P3, P4, and Tr1-Tr3 resulted from local tectonic events at the margin of the Arabian platform (Hulw half-graben). The presented sea level curve corresponds therefore to the Tethyan sea level curve during the Cisuralian and Guadalupian, but differs significantly during the Lopingian, as a result of the dispersal of Pangea. The Middle and Upper Triassic sea level curve from Oman is again in good correlation with published data. The Permian and Triassic sequence architecture on the Arabian plate and adjacent Neo-Tethys was predominantly triggered by the global warming after the Permian-Carboniferous glaciation, the initial rifting of Neo-Tethys, and subordinately by eustatic sea level changes.

Weidlich, O.; Bernecker, M.

2003-05-01

172

Permian stratigraphy and correlation of Northeast China: A review  

Science.gov (United States)

Palaeontological, lithostratigraphical data from the Permian strata and correlation of the Permian successions for different tectonic units in Northeast China are reviewed and summarized in this paper. Permian strata in Northeast China are dominated by brachiopods, fusulinoideans and land plants, with limited ammonoids, conodonts and bivalves. The Cisuralian (Early Permian) in the northern margin of the North China Block and in the Manchuride Belt is composed mostly of marine massive limestone with the characteristic Pseudoschwagerina Zone in the Asselian and Sakmarian and the Misellina claudiae Zone in the Kungurian. The Cisuralian in the Xing'an Block and the northeastern part of Inner Mongolia is dominated by huge terrestrial deposits with fossil plants. The Guadalupian (Middle Permian) in the Manchuride, Altaid and Yanbian Belts are characterized by bi-temperate Roadian or early Wordian Monodiexodina fauna and the late Wordian-Capitanian Codonofusiella- Schwagerina or Neoschwagerina- Yabeina faunas, the mixed brachiopod faunas between the Boreal/antitropical and the Palaeoequatorial Cathaysian forms, the Roadian or early Wordian solitary coral faunas, and the late Wordian-Capitanian compound Waagenophyllum- Wentzelella fauna. The Nadanhada Terrane contains some exotic limestone blocks with a typical Cathaysian Neoschwagerina- Yabeina fauna in a Late Jurassic-Early Cretaceous mélange, which is related to Mesozoic subduction in the western Circum-Pacific region. The Lopingian (Late Permian) in Northeast China is mostly characterized by terrestrial molasse deposits with a mixed flora between the Boreal Angaran and the palaeoequatorial Cathaysian Provinces, indicating the final closure of the Palaeo-Asian Ocean.

Shen, S.-Z.; Zhang, H.; Shang, Q. H.; Li, W.-Z.

2006-03-01

173

Catastrophic dispersion of coal fly ash into oceans during the latest Permian extinction  

Energy Technology Data Exchange (ETDEWEB)

During the latest Permian extinction about 250 Myr ago, more than 90% of marine species went extinct, and biogeochemical cycles were disrupted globally. The cause of the disruption is unclear, but a link between the eruption of the Siberian Trap flood basalts and the extinction has been suggested on the basis of the rough coincidence of the two events. The flood basalt volcanism released CO{sub 2}. In addition, related thermal metamorphism of Siberian coal measures and organic-rich shales led to the emission of methane, which would have affected global climate and carbon cycling, according to model simulations. This scenario is supported by evidence for volcanic eruptions and gas release in the Siberian Tunguska Basin, but direct indicators of coal combustion have not been detected. Here we present analyses of terrestrial carbon in marine sediments that suggest a substantial amount of char was deposited in Permian aged rocks from the Canadian High Arctic immediately before the mass extinction. Based on the geochemistry and petrology of the char, we propose that the char was derived from the combustion of Siberian coal and organic-rich sediments by flood basalts, which was then dispersed globally. The char is remarkably similar to modern coal fly ash, which can create toxic aquatic conditions when released as slurries. We therefore speculate that the global distribution of ash could have created toxic marine conditions.

Grasby, S.E.; Sanei, H.; Beauchamp, B. [Geological Survey Canada Calgary, Calgary, AB (Canada)

2011-02-15

174

Dalhart's only Permian field gets best oil well  

Energy Technology Data Exchange (ETDEWEB)

This paper reports that activity is picking up in Proctor Ranch oil field in the northwestern Texas panhandle, the only Permian producing field in the lightly drilled Dalhart basin. During the last 2 1/2 months, the field has a new operator and a new producing well, the best of five drilled since discovery in 1990. Corlena Oil Co., Amarillo, acquired the field from McKinney Oil Co. in May and tested its first well in early July. The 1-64 Proctor, 18 miles west of Channing, pumped at rates as high as 178 bd of oil and 6 b/d of water from Permian Wolfcamp dolomite perforations at 4,016-29 ft. Corlena plans to drill another well south of the field soon. The lease requires that the next well be spudded by early November. The field appears to be combination structural-stratigraphic trap in which the dolomite pinches out against the Bravo Domes-Oldham nose to the west.

1992-07-20

175

Molecular distributions and geochemical implications of pyrrolic nitrogen compounds in the Permian Phosphoria Formation derived oils of Wyoming  

Energy Technology Data Exchange (ETDEWEB)

Crude oils from the Laramide structures of Wyoming were studied with respect to their geochemical compositions. The sampling areas include the Greater Green River, Wind River and Big Horn basins, and the Casper Arch region. Based on pristane/phytane ratio and various hopane and sterane parameters, the Permian Phosphoria Formation derived oils can be readily differentiated from oils with different origins. Within the Phosphoria Formation derived oils, three subgroups can be identified using T{sub s}/(T{sub s} + T{sub m}) and diasterane/regular sterane ratios, corresponding to sources with subtle variation in organic facies and/or thermal maturity of the Phosphoria Formation. Differences in source organic input, depositional environments, and thermal maturity were observed to greatly influence the saturated hydrocarbon compositions of the Permian Phosphoria Formation derived oils. However, the distributions of pyrrolic nitrogen compounds in these oils do not appear as diagnostic as the conventional hydrocarbon parameters commonly used as indicators of these geological factors. This fact may be related to the more significant role of oil migration in the modification of pyrrolic nitrogen compound distributions in foreland basins as compared to that in rift basins. The recognition of possible source and maturity effects on pyrrolic nitrogen compounds suggests that all of these factors should be taken into proper consideration before the pyrrolic nitrogen compounds are used as indicators for any specific geological process. (Author)

Silliman, J.E.; Li, M.; Yao, H. [Geological Survey of Canada, Calgary, Alberta (Canada); Hwang, R. [Chevron Petroluem Technology Company, Richmond, CA (United States)

2002-05-01

176

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

Science.gov (United States)

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

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

2012-11-01

177

Nitrogen isotope chemostratigraphy across the Permian-Triassic boundary at Chaotian, Sichuan, South China  

Science.gov (United States)

Nitrogen isotopic compositions of upper Permian to lowermost Triassic rocks were analyzed at Chaotian in northern Sichuan, South China, in order to clarify changes in the oceanic nitrogen cycle around the Permian-Triassic boundary (P-TB) including the entire Changhsingian (Late Late Permian) prior to the extinction. The analyzed ca. 40 m thick interval across the P-TB at Chaotian consists of three stratigraphic units: the upper Wujiaping Formation, the Dalong Formation, and the lowermost Feixianguan Formation, in ascending order. The upper Wujiaping Formation, ca. 10 m thick, is mainly composed of dark gray limestone with diverse shallow-marine fossils such as calcareous algae and brachiopods, deposited on the shallow shelf. In contrast, the overlying Dalong Formation, ca. 25 m thick, is mainly composed of thinly bedded black mudstone and siliceous mudstone containing abundant radiolarians, deposited on the relatively deep slope/basin. Absence of bioturbation, substantially high total organic carbon contents (up to 15%), and abundant occurrence of pyrite framboids in the main part of the Dalong Formation indicate deposition under anoxic condition. The lowermost Feixianguan Formation, ca. 5 m thick, is composed of thinly bedded gray marl and micritic limestone with minor fossils such as ammonoids and conodonts, deposited on the relatively shallow slope. ?15NTN values are in positive values around +1 to +2‰ in the upper Wujiaping Formation implying denitrification and/or anammox in the ocean. ?15NTN values gradually decrease to -1‰ in the lower Dalong Formation and are consistently low (around 0‰) in the middle Dalong to lowermost Feixianguan Formation. No clear ?15NTN shift is recognized across the extinction horizon. The consistently low ?15NTN values suggest the enhanced nitrogen fixation in the ocean during the Changhsingian at Chaotian. Composite profiles based on previous and the present studies demonstrate the substantial ?15N variation on a global scale in the late Permian to earliest Triassic; a systematic ?15N difference by low and high latitudes is particularly clarified. Although the enhanced nitrogen fixation throughout the Changhsingian at Chaotian was likely a regional event in northwestern South China, the composite ?15N profiles imply that the sea area in which fixed nitrogen is depleted has gradually developed worldwide in the Changhsingian, possibly acting as a prolonged stress to shallow-marine biota.

Saitoh, Masafumi; Ueno, Yuichiro; Nishizawa, Manabu; Isozaki, Yukio; Takai, Ken; Yao, Jianxin; Ji, Zhansheng

2014-10-01

178

An upwelling model for the Phosphoria sea: A Permian, ocean-margin sea in the northwest United States  

Science.gov (United States)

The Permian Phosphoria Formation, a petroleum source rock and world-class phosphate deposit, was deposited in an epicratonic successor basin on the western margin of North America. We calculate the seawater circulation in the basin during deposition of the lower ore zone in the Meade Peak Member from the accumulation rates of carbonate fluorapatite and trace elements. The model gives the exchange rate of water between the Phosphoria sea and the open ocean to the west in terms of an upwelling rate (84 m yr-1) and residence time (4.2 yr) of seawater in the basin. These hydrographic properties supported a mean rate of primary productivity of 0.87 g m-2 d-1 of carbon in the uppermost few tens of meters of the water column (the photic zone) and denitrifying redox conditions in the bottom water (below approximately 150 m depth). High rain rates, onto the sea floor, of the organic matter that hosted the phosphate and several trace elements contributed to the accumulation of phosphorite, chert, and black shales and mudstones. Evaporation in the Goose Egg basin to the east of the Phosphoria basin ensured the import of surface seawater from the Phosphoria sea. Budgets of water, salt, phosphate, and oxygen, plus the minor accumulation of the biomarker gammacerane, show that exchange of water between the two basins was limited, possibly by the shallow carbonate platform that separated the two basins.

Piper, D. Z.; Link, P. K.

2002-01-01

179

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

180

Water mass denitrification during the latest Permian extinction in the Panthalassic Ocean  

Science.gov (United States)

The latest Permian extinction (LPE) event, about 252 Myr ago, resulted in the disappearance of >90 % of marine and terrestrial species. Possible explanations invoke, Siberian Trap volcanism, anoxia, H2S poisoning draw down of bioessential elements or a combination of these. Recent observation of coal ash dispersion into global oceans prior to LPE suggest global ash fall could have created toxic marine (terrestrial) conditions. Recent work also suggests volcanic mercury emissions may have added to toxic marine conditions. While development of marine euxinic conditions in the Tethyan region across the LPE is widely accepted, inferences on the redox and environmental conditions of the Panthalassic Ocean more equivocal. Indications of (photic zone) euxinia occur in marginal areas of Panthalassa. In central pelagic areas, however, expansion of low oxygen conditions across the LPE may be restricted to the oxygen minimum zone rather than towards the photic zone or the seafloor. Here, we report the ?15N isotopic signature in Late Permian - Early Triassic sediments from the Buchanan Lake section in the Sverdrup Basin, Canadian Arctic. Deep water marine sedimentation in the Sverdrup Basin, connected to Panthalassa via a western seaway, allows inferences on the nitrogen cycling across the LPE. We confirm that expansion of low oxygen conditions in the Panthalassic Ocean began prior to the paleo-Tethys Ocean. Further, the detailed correspondence of changes in denitrification, nitrate utilization/fixation across the LPE in both oceans indicate rapid reorganization of the marine ecosystem in response to changes in nutrient inventories, probably mediated through the eruption of the Siberian Traps.

Knies, J.; Grasby, S.; Beauchamp, B.; Schubert, C.

2012-04-01

 
 
 
 
181

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

182

Subvolcanic rocks intercalated with alluvial Middle-Upper Permian sediments in the Alcotas Fm., Iberian Range, Eastern Spain: Paleogeographic and tectonic significance  

Science.gov (United States)

Permian and Triassic alluvial sediments of the Iberian Range, an intracratonic, linear alpine structure occupying central and eastern Spain, were deposited in the fault-bounded Iberian Basin during an extensional period. The earliest sedimentary infill consists of alluvial deposits subdivided into three unconformity-bounded macrosequences. The second of these sequences is late Guadalupian to early Lopingian (Middle-Late Permian) in age and consists of the Boniches and Alcotas Fms., the latter one being the focus of this study. The Alcotas Fm. may reach 170m in thickness and consists of red siltstones and clays and associated lenticular conglomerate and sandstone bodies of tens to hundreds metres length and decimetric to metric in thickness. Isolated levels of volcaniclastic sediments have been recently found in the eastern part of the basin. These sediments represent the youngest Paleozoic volcaniclastic events found up to now in the Iberian Basin. The sub-volcanic rocks occur as five lenticular bodies tens of metres long and less than 1m in thickness found near Alfondeguilla village. Centimetric-scale cooling edges and a central doleritic texture can be recognized within each of these lenticular bodies. The mineral assemblage is formed by weathered olivine (7 %), plagioclase (80 %) with compositions ranging between An97 - An50, Ti-augite (15-10 %) with compositions between En50Wo42Fs8 - En40Wo38Fs22, and minor percentages of oxides (namely magnetite and ilmenite) and Cl-apatite. Compositional trend of Ti-augite and plagioclase are indicative of an alkaline affinity. The temperatures estimated from Ti-augite extreme compositions (Fs8 and Fs22) range between 1200 to 700 °C. The location of these bodies is related to the intersection of two perpendicular fault systems in the basin orientated NW-SE and NE-SW that played an important role during the first stages of the Iberian Basin development. Chemical composition shows high contents in MgO, TiO2 (1.71 %), and P2O5 (0.5 %), as well as Nb, Ta and La, indicative of alkaline affinity. Trace elements relationships indicate an astenospheric mantle source. These compositions are similar to those found in the Middle Permian alkaline basalts of the Pyrenean Range. These results allow to establish a new alkaline magmatism of probable Middle Permian age, linked to a deep rifting structure, which started during Early Permian times with a calc-alkaline magmatism.

Lago, Marceliano; de La Horra, Raul; Galan-Abellan, Belen; Barrenechea, Jose F.; Lopez-Gomez, Jose; Alonso-Azcarate, Jacinto; Benito, M. Isabel; Luque, Javier; Arche, Alfredo

2010-05-01

183

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

184

Structural evolution of the early Permian Nambucca Block (New England Orogen, eastern Australia) and implications for oroclinal bending  

Science.gov (United States)

Paleozoic to early Mesozoic southern New England Orogen of eastern Australia exhibits a remarkable ear-shaped curvature (orocline), but the geodynamic processes responsible for its formation are unclear. Oroclinal bending took place during the early Permian, simultaneously with the deposition of the rift-related Sydney, Gunnedah, and Bowen basins, which bound the oroclines to the west. The Nambucca Block is another early Permian rift basin, but it is situated in the core of the oroclinal structure. Here we present new stratigraphic, structural, and geochronological data from the Nambucca Block in an attempt to better understand its tectonic history and relationships to the formation of the oroclines. We recognized four phases of folding and associated structural fabrics (S1-4), with the second phase (S2) dated at 275-265 Ma by 40Ar/39Ar geochronology of muscovite. This age overlaps with independent constraints on the timing of oroclinal bending, suggesting that the earlier two phases of deformation in the Nambucca Block (F1 and F2) were associated with orocline formation. We propose that oroclinal bending involved three major stages. The first stage (plate coupling that was possibly linked to flat-slab subduction.

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

2014-07-01

185

Ground-water hydraulics of the deep-basin brine aquifer, Palo Duro Basin, Texas panhandle  

International Nuclear Information System (INIS)

The Deep-Basin Brine aquifer of the Palo Duro Basin (Texas Panhandle) underlies thick Permian bedded evaporites that are being evaluated as a potential high-level nuclear waste isolation repository. Potentiometric surface maps of 5 units of the Deep-Basin Brine aquifer were drawn using drill-stem test (DST) pressure data, which were analyzed by a geostatistical technique (kriging) to smooth the large variation in the data. The potentiometric surface maps indicate that the Deep-Basin Brine aquifer could be conceptually modeled as 5 aquifer units; a Lower Permian (Wolfcamp) aquifer, upper and lower Pennsylvanian aquifers, a pre-Pennsylvanian aquifer, and a Pennsylvanian to Wolfcampian granite-wash aquifer. The hydraulic head maps indicate that ground-water flow in each of the units is west to east with a minor northerly component near the Amarillo Uplift, the northern structural boundary of the basin. The Wolfcamp potentiometric surface indicates the strongest component of northerly flow. Inferred flow direction in Pennsylvanian aquifers is easterly, and in the pre-Pennsylvanian aquifer near its pinch-out in the basin center, flow is inferred to be to the north. In the granite-wash aquifer the inferred flow direction is east across the northern edge of the basin and southeast along the Amarillo Uplift

186

Did an Impact Trigger the Permian-Triassic Extinction?  

Science.gov (United States)

This resource, authored by David Morrison, contains the National Aeronautics and Space Administration's Astrobiology Institute news story on new evidence of a 251-million year-old impact crater off the western coast of Australia that may have caused the "Great Dying", the Permian-Triassic extinction event.

Morrison, David

2009-05-26

187

The Permian Huangshanxi Cu-Ni deposit in western China: intrusive-extrusive association, ore genesis, and exploration implications  

Science.gov (United States)

The Permian Huangshanxi Cu-Ni deposit is the second largest magmatic sulfide deposit discovered to date in a major Ni-Cu province related to protracted basaltic magmatism in eastern Xinjiang, China. It is hosted by a small mafic-ultramafic intrusion comprised predominantly of lherzolites, olivine websterites, gabbronorites, and gabbros. The Huangshanxi intrusion is coeval with Permian basalts of tholeiitic and alkaline affinities in the Tuha and Tarim basins, respectively. To evaluate a possible genetic relationship between the Huangshanxi intrusion and a specific type of coeval basalt in the region, as well as ore genesis in the intrusion, we have carried out an integrated mineralogical, petrological, and geochemical study. Our data reveal that the Huangshanxi intrusive rocks are characterized by relatively flat chondrite-normalized REE patterns, depletion in Nb and Ta, and elevated ?Nd values varying between 6 and 10. These features are similar to those of coeval tholeiitic basalts in the nearby Tuha basin, but are significantly different from those of coeval alkaline basalts in the relatively remote Tarim basin. The geochemical similarities and differences suggest that the Huangshanxi intrusion is genetically related to the tholeiitic basalts in the Tuha basin, not to the alkaline basalts in the Tarim basin, as suggested previously by some researchers. This implies that regional exploration for the Huangshanxi-type Cu-Ni deposits should be centered in the Tuha basin instead of the Tarim basin. More specifically, the uplifted areas around the Tuha basin where similar intrusions may have been brought close to the surface should be carefully examined for mineralization potential. Intrusive relations and mass balance constraints from incompatible trace elements and sulfide abundances suggest that the Huangshanxi intrusion represents a dynamic magma conduit through which multiple pulses of magma ascended to higher levels or to the surface. Numerical simulation of magma evolution and mixing calculations using Sr-Nd isotopes indicate that selective assimilation of S-bearing crustal materials is important for sulfide saturation during the early stages of magma evolution when lherzolites formed. Fractional crystallization may have also played a role in the attainment of sulfide saturation during the later stages of magma evolution when olivine websterites and gabbronorites formed. In both cases, immiscible sulfide droplets were retained in the conduit to form disseminated sulfide lenses while the fractionated silicate liquids and buoyant phases such as plagioclase continued to ascend. Extremely low PGE tenors in the sulfide ores of the Huangshanxi deposit suggest that the parental magma was highly depleted in chalcophile elements possibly due to previous sulfide segregation at depth.

Zhang, Mingjie; Li, Chusi; Fu, Piaoer; Hu, Peiqing; Ripley, Edward M.

2011-02-01

188

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)

189

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.

2004-03-01

190

Lipid Biomarker Records Across the Permian-Triassic Boundary from Kap Stosch, Greenland  

Science.gov (United States)

The end-Permian extinction was the most severe in the past 500 million years of the Earth's history and evidence that an oceanic anoxic event (OAE) occurred contemporaneously has been presented previously [1,2]. OAEs have, therefore, been proposed as responsible for the mass mortality, and if the anoxic ocean was also euxinic, the release of hydrogen sulfide during upwelling and/or transgression provides an extinction agent in the ocean as well as on land. Chlorobiaceae, as indicators of photic zone euxinia (PZE), utilize hydrogen sulfide as an electron donor for anoxygenic photosynthesis. The detection of isorenieratane and a series of short-chain monoaromatic aryl isoprenoids, biomarkers for Chlorobiaceae, in sediments indicates the presence of hydrogen sulfide in the photic zone of the water column during sediment deposition. The Kap Stosch area in Eastern Greenland was identified as a Permian-Triassic boundary (PTB) outcrop of homogeneous shale, silty shale, and siltstone facies [3]. Another late Permian section in Eastern Greenland, the Ravnefjeld Formation, has framboidal pyrites indicative of sulfidic deep water [4]. A sample suite from the Kap Stosch region was studied using standard organic geochemistry methods including stable isotopic analyses of organic carbon, Rock-Eval pyrolysis, and biomarker hydrocarbon analysis. Aryl isoprenoids, including isorenieratane, were present in all samples studied and the concentrations were observed to fluctuate in tandem with TOC, similar to other Mesozoic OAEs. The molecular ratios of pristane/phytane and hopanes/steranes as well as the 2-methyl-hopane index (2-MHI) fluctuated dramatically through this section as they do at the type section at Meishan and in the Perth Basin [5]. The 2-MHI shows an inverse pattern to the total aryl isoprenoids, perhaps indicative of instability in the form of primary productivity in the water column during euxinic episodes. This can result in nitrogen limitation and a competitive advantage of cyanobacteria over microalgae for nutrient resources [6]. Overall, the biomarker patterns in these samples indicate the presence of PZE at this location leading up to and continuing through the PTB. 1. Isozaki Y., 1997. Science 276, 235. 2. Wignall P. and R. Twichett, 1996. Science 272, 1155. 3. Teichert C. and B. Kummel, 1972. Bull. Canadian Petrol. Geol. 20, 659. 4. Nielsen J. and Y. Shen, 2004. Geology 32, 1037. 5. Grice K., et al., 2005. Science 307, 706. 6. Kuypers M., et al., 2004. Geology 32, 853.

Hays, L. E.; Love, G. D.; Foster, C. B.; Grice, K.; Summons, R. E.

2006-12-01

191

Permian Triassic palynofloral transition in Chintalapudi area, Godavari Graben, Andhra Pradesh, India  

Science.gov (United States)

The entire 606 m-thick sedimentary sequence in borecore MCP-7 from Chintalapudi area, Chintalapudi sub-basin has been lithologically designated as Kamthi Formation. However, the palynological investigation revealed five distinct palynoassemblages, which essentially fall under two groups, one group (Palynoassemblage-I, II and III) having dominance of striate disaccates along with presence of some stratigraphically significant taxa, belongs to Late Permian (Raniganj) palynoflora, while the other group (Palynoassemblages IV and V) shows sharp decline in percentage of characteristic taxa of first group, i.e., striate disaccates, and consequent rise or dominance of taeniate and cingulate cavate spores, belongs to Early Triassic (Panchet) palynoflora. Palynoassemblage-I, II and III (Group I) are characterized by dominance of striate disaccates chiefly, Striatopodocarpites spp. and Faunipollenites spp. along with presence of rare but stratigraphically significant taxa, viz., Gondisporites raniganjensis, Falcisporites nuthaliensis, Klausipollenites schaubergeri, Chordasporites sp., Striomonosaccites, ovatus, Crescentipollenites multistriatus, Verticipollenites debiles, Strotersporites crassiletus, Guttulapollenites hannonicus, G. gondwanensis, Hamiapollenites insolitus, Corisaccites alutus, Lunatisporites ovatus, Weylandites spp. and Vitreisporites pallidus. Palynoassemblage-I is distinguished by significant presence of Densipollenites spp. while Palynoassemblage-II shows significant presence of Crescentipollenites spp. and Palynoassemblage-III differs from the above two assemblages in having significant presence of Guttulapollenites hannonicus. Palynoassemblage-IV (Group II) is characterized by high percentage of taeniate disaccates chiefly Lunatisporites spp., while Palynoassemblage-V (Group II) is characterized by cingulate-cavate trilete spores chiefly, Lundbladispora spp. and Densoisporites spp. Striate disaccates show a sharp decline in these two assemblages. In Chintalapudi area Late Permian and Early Triassic palynoflora has been recorded for the first time indicating existence of Raniganj and Panchet sediments as well. The study further supports the earlier studies of Jha and Srivastava (1996) that Kamthi Formation represents Early Triassic (=Panchet Formation) overlying Raniganj equivalent sediments with a gradational contact.

Jha, Neerja; Chary, M. Basava; Aggarwal, Neha

2012-10-01

192

Reconstruction of Pseudomariopteris busquetii, a vine-like Late Carboniferous-Early Permian pteridosperm.  

Science.gov (United States)

The growth habit of the Late Carboniferous-Early Permian pteridosperm Pseudomariopteris busquetii is reconstructed based on compression material from the upper Stephanian of the Blanzy-Montceau and Commentry Basins (Massif Central, France), and the upper Rotliegend of the Saar-Nahe Basin (Nahe Group, N 4, Rheinland Pfalz, Germany). Pseudomariopteris busquetii was a medium-sized, vine- to liana-like plant with slender stems to which small bipartite fronds were attached. What is most interesting is that the species used at least two different strategies to both anchor and support the plant body. Most specimens possess specialized climber hooks developed from apical extensions of the pinna axes, indicating that the fronds were used to attach the plant. A few specimens suggest that the stem may also have had some capacity for attachment. In the absence of suitable supports, however, P. busquetii was apparently able to grow in dense stands or thickets in which the individual plants supported each other. PMID:11353702

Krings, M; Kerp, H; Taylor, E L; Taylor, T N

2001-05-01

193

Late Permian (Zechstein) rifting in the Netherlands: models and implications for petroleum geology  

Energy Technology Data Exchange (ETDEWEB)

Multidisciplinary studies in the Netherlands have revealed two new phases of late Variscan extensional faulting during the Late Permian. The names Tubantian I and II are proposed in this paper. Tubantian I movements were triggered by rapid deposition and loading of anhydrite upon a differentiated basement, in combination with mild E-W extension. A series of small pull-apart basins and tilted fault blocks formed and local collapse occurred of the Variscan Front. The relief was subsequently filled with carbonates and evaporites of the Z1 (Werra) Formation. Fault movements stopped prior to deposition of the Z2 (Stassfurt) Formation. Tubantain II movements caused uplift and erosion, especially in the southern onshore Netherlands. Contemporaneously, sandy erosional products were deposited in the southwestern offshore areas of the Netherlands and the adjacent UK sector and playa-type halites and claystones accumulated in the central parts of the basin. Three features have implications for hydrocarbon exploration: the early formation of fault/dip closed structures shortly after deposition of the Upper Rotliegend; the reorganisation of the fluid-flow system and the deposition of contemporaneous sandy deposits. (Author)

Geluk, Mark [Netherlands Inst. of Applied Geoscience TNO - National Geological Survey, Utrecht (Netherlands)

1999-05-01

194

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

195

Frequencies of solar activity in laminated anhydrite of Upper Permian age (Zechstein-cycle 2)  

Science.gov (United States)

Upper Permian Zechstein contains seven evaporitic cycles that were deposited in an epicontinental sea expanding from E-England to Poland. Zechstein-cycles 1 to 3 show a sequence of marine pelite, overlain by marine carbonate and evaporites (in the order sulfate, halite containing possibly anhydrite and potassium salts, and regressive sulphate at the top). Whereas the marginal facies of the lower sulphate horizon of Zechstein-cycle 2 (Stassfurt cycle) consists of massive anhydrite, its basin facies shows in the lower part a fine lamination of white anhydrite alternating with thin black organic carbon rich layers. These laminations are supposed to be annually deposited layers. The black laminae originate from the annual bloom of algae. Layer thickness is about 0.4 to 1.0 mm and increases from basin centre to more marginal positions. The individual layers can be traced over 300 km within the NW-German Basin. The previously described variability of layer thickness requires a forcing mechanism that is effective over long distances and must be also highly periodic. Also, varying layer thicknesses indicate varying anhydrite precipitation, i. e. probably changes in water temperatures which in turn point to climatic influences on the deposition of the layers. Here we re-examined records of cycle thickness (up to 700 laminae) determined by G. Richter-Bernburg in the 1950ties using modern techniques of time series analysis, e. g. wavelet analysis. We could detect cycles with periods of 10-14 years and 90 years which are close to known cycles of solar activity.

Hiete, M.; Berner, U.

2003-04-01

196

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

197

Palaeoecological aspects of some invertebrate trace fossils from the mid- to Upper Permian Middleton Formation (Adelaide Subgroup, Beaufort Group, Karoo Supergroup), Eastern Cape, South Africa  

Science.gov (United States)

Ichnological and sedimentological analyses in the Eastern Cape allowed the first description of a Cochlichnus-dominated ichnofossil site from the mid- to Upper Permian Middleton Formation (Karoo Supergroup) in South Africa. The locality is within the uppermost Pristerognathus Assemblage Zone, a biostratigraphic interval characterized by a low vertebrate biodiversity at the turn of the mid- to Late Permian. Our field data indicates that the surficial bioturbation of very fine to fine-grained sand layers resulted from life activities of shallow infaunal and epifaunal invertebrates (possibly annelids, aquatic oligochaetes, nematodes, insect larvae) and fish. The morphology of the trails, their relationship to the substrate and the behaviour inferred from them indicate that the tracemakers developed a strategy that facilitated the optimization of low food resources in a permanently submerged freshwater setting. Combined ichnological and sedimentological evidence suggests a low-energy, freshwater lacustrine depositional environment, where occasional higher energy currents brought nutrients. Data also imply that colonization of these erratic event beds by opportunistic sediment-feeders was short-lived and followed by longer intervals of lower energy deposition under possibly poorly oxygenated conditions. We propose that these event beds as well as the sporadic red mudstones of the Middleton Formation may have formed during short-term, higher storm-frequency and dryer periods, signalling changes in the otherwise humid climate in this part of the main Karoo Basin during the mid- to Late Permian.

Bordy, Emese M.; Linkermann, Sean; Prevec, Rose

2011-10-01

198

Volatile Release from The Siberian Traps and the End-Permian Environment  

Science.gov (United States)

The Siberian Traps (ca. 252 Ma) is one of the most voluminous known eruptions of continental basaltic magma, and has been invoked as a trigger for the end-Permian mass extinction: the single largest loss of biological diversity in the Phanerozoic. Constraining the degassing of volatiles such as sulfur, chlorine, fluorine, and carbon dioxide is critical to understanding the environmental consequences of flood basalt emplacement. We measured concentrations of these volatiles in melt inclusions in olivine, plagioclase and clinopyroxene crystals from Siberian Traps lavas, sills, and tuffs. New ion probe analysis results provide insight into the volatile budget of the earliest pyroclastic and later flow-dominated periods of flood volcanism. In particular, melt inclusions from four flows and tuffs belonging to the stratigraphically lowest extrusive suites provide the first estimates of dissolved volatiles within early-erupted Siberian Traps magmas. Comparison with studies of melt inclusions from Iceland’s Laki eruption, the Deccan Traps and the Columbia River flood basalts suggests that Cl, F, and S concentrations in some Siberian Traps magmas were anomalously high. Measured concentrations reach 0.75 wt % Cl and 1.95 wt % F in one sample. In other samples, we also measure significant concentrations of S, Cl, F, and C. We hypothesize that assimilation of evaporites and other sedimentary rocks from the Tunguska basin might have contributed to the volatile budget of Siberian magmatism. Our melt inclusion data, in conjunction with the present-day volumes of the associated flows, sills, and tuffs, indicate that even individual Siberian Traps eruption events probably carried massive volatile loads. We observe tuff sequences tens to hundreds of meters thick near the base of the volcanic sequence in the Maymecha-Kotuy and Angara regions; these volcaniclastic deposits may reach 700 meters in thickness in the central Tunguska basin. Locally well-preserved accretionary lapilli provide evidence that many of these deposits are primary pyroclastic rocks. These explosive episodes may have enhanced the efficiency with which degassing volatiles were entrained into an ascending thermal plume. The high volatile contents we observe in many Siberian Traps rocks, if injected into the stratosphere, may have significantly contributed to ozone depletion and a drastic deterioration in global environmental conditions at the time of the Permian-Triassic boundary.

Black, B. A.; Elkins-Tanton, L. T.; Rowe, M. C.; Ukstins Peate, I.

2010-12-01

199

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

200

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

International Nuclear Information System (INIS)

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

 
 
 
 
201

Permian basalts and trachytes from Esterel (SE France): a transitional tholeiitic suite emplaced during lithosphere thinning; Basaltes et trachytes permiens de l`Esterel (SE France): une serie tholeiitique transitionnelle epanchee pendant l`amincissement lithospherique  

Energy Technology Data Exchange (ETDEWEB)

Geochemical (major, trace and rare earth elements) and isotopic ({sup 143}Nd/{sup 144}Nd) 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 {epsilon}Nd{sub (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 {epsilon}Nd{sub (T=250Ma)} of +4/+5. These high {xi}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) 37 refs.

Lapierre, H.; Basile, Ch. [Grenoble-1 Univ., 38 - Grenoble (France). Laboratoire de Geodynamique des Chaines Alpines, CNRS UPRES-A5025; Dupuis, V. [Institut de Geodynamique, UMR Geosciences Azur, 06 - Valbonne (France)

1999-11-01

202

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2003-07-01

203

Hydrocarbon accumulations in the Tarim basin, China  

Energy Technology Data Exchange (ETDEWEB)

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

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

1996-10-01

204

Permian U-Pb (CA-TIMS) zircon ages from Australia and China: Constraining the time scale of environmental and biotic change  

Science.gov (United States)

In eastern Australia, the interconnected Bowen and Sydney Basins are filled with terrestrial sediments of late Paleozoic to early Mesozoic age. These sedimentary units record significant evolutionary events of eastern Gondwana during the time interval between two major mass extinctions (end Middle Permian and Permian-Triassic), and also provide lithological evidence for the Carboniferous-Permian Late Paleozoic Ice Age of southern Pangea, considered to be divisible into up to seven discrete glaciation events in Australia [e.g., 1]. These glaciations are currently assigned ages that indicate that the last of the glaciations predate the end Middle Permian mass extinction at ca. 260 Ma. However, the estimates for the time and durations are largely based on biostratigraphy and lithostratigraphy that, in the absence of robust and precise radioisotopic ages, are unacceptably fragile for providing an accurate high-resolution framework. Interbedded with the sediments are numerous tuff layers that contain zircon, many of which are associated with extensive coal measures in the Sydney and Bowen Basins. Published SHRIMP U-Pb zircon ages [2, 3] have been shown to be less precise and inaccurate when compared to ages applying the CA-TIMS method to the same horizons. Also within the late Middle Permian, the eruption of the Emeishan flood basalts in SW China has been proposed to have caused the end Middle Permian mass extinction [e.g., 4], though a causal link between these events demands a rigorous test that can only be provided by high-resolution geochronology. We present new U-Pb (CA-TIMS) zircon ages on tuff layers from the Sydney and Bowen Basins, with the purpose of generating a timescale for the Upper Permian of Australia to allow correlation with different parts of the world. Initial results, with permil precision, date a tuff layer within the uppermost Bandanna Fm. to ca. 252 Ma, a tuff within the Moranbah Coal Measures to ca. 256 Ma, and a tuff within the Ingelara Fm. to ca. 257 Ma, the latter two units lying stratigraphically below the latest identified glacial deposits. U-Pb (CA-TIMS) results on zircons from the Emeishan flood basalts and related volcanic products confirm the end-Guadalupian age (ca. 260 Ma) of the magmatism, and based on present data, place the Emeishan volcanic event (and its possibly associated mass extinction) within the occurrence of the Late Paleozoic Ice Age. This study’s primary goal is the establishment of a chronostratigraphic framework that would allow the integration of calibrated records from both terrestrial and marine units from different parts of the world in order to constrain the timing and rates of extinctions and recoveries in different locations and physical environments. [1] Fielding et al. (2008), J. Geol Soc. Lon., v. 165, pp. 129-140 [2] Michaelsen et al. (2001), Aus. J. Earth Sci., v. 48, pp. 183-192 [3] Roberts et al. (1996), Aus. J. Earth Sci., v. 43, pp. 401-421 [4] He et al. (2007), EPSL, v. 255, pp. 306-323

Denyszyn, S. W.; Mundil, R.; Metcalfe, I.; He, B.

2010-12-01

205

Ar-40/Ar-39 ages of Meishan Bed 25 sanidine and igneous intrusions from the Siberian platform compared: implications for the timing of gas emissions and the End-Permian extinction  

Science.gov (United States)

The end-Permian mass extinction wiped out nearly all life on our planet. The cause for this cataclysmic event and whether this appeared as a double extinction is a matter of current debate. The most favoured candidate is volatile release from either magmatic degassing directly or induced by interaction between magmas and volatile bearing deposits. Release of volatiles during thermal metamorphism and assimilation of coal and evaporite deposits which are widespread on the Siberian platform following igneous intrusion has been proposed as a major cause of the environmental and extinction event at the end of the Permian, with venting of carbon gases and halocarbons to the atmosphere leading to global warming and atmospheric ozone depletion (Svensen et al., 2009). To meaningfully examine this proposed causality requires precise dating of the Siberian intrusions at the ';Earthtime' goal of × 0.1 % or better. Here we present preliminary results from Ar-40/Ar-39 step heating experiments on plagioclase and biotite from Siberian basin intrusions and compare the data with published and new Ar-40/Ar-39 sanidine ages for Bed 25 from the global section and Permian-Triassic boundary stratotype at Meishan, China. REFERENCES H. Svensen et al., Siberian gas venting and the end-Permian environmental crisis, Earth and Planetary Science Letters, volume 277, 490-500, 200

Storey, M.; Reichow, M. K.; Saunders, A. D.

2013-12-01

206

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

Directory of Open Access Journals (Sweden)

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

ELISEU V. DIAS

2001-03-01

207

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.

2001-03-01

208

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

209

Ocean redox change at the Permian-Triassic mass extinction  

DEFF Research Database (Denmark)

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

Ruhl, Micha; Bjerrum, Christian J.

2013-01-01

210

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

211

New Permian Insects Discovered in Kansas and Oklahoma.  

Science.gov (United States)

The Midco insect bed of Oklahoma and a newly discovered insect bed above this were traced across Kay County, Okla., into Sumner County, Kan. As a result, a greater time span is available for study of insect evolution during the mid-continent Permian, and the exact stratigraphic correlation of the Wellington of Oklahoma and Kansas can now be demonstrated. Four insect orders have thus far been identified from the new insect bed: Protodonata, Odonata, Protoperlaria, and Ephemeroptera. Numerous new species and higher categories are included in the collections from the two insect beds. PMID:17781391

Tasch, P; Zimmerman, J R

1959-12-11

212

The delta 13C record of Devonian to Permian carbonates  

Science.gov (United States)

A ?13Ccarb curve will be presented for samples spanning the time interval from the Silurian/Devonian to the Permian/Triassic boundary. Reliable data are usually based on analyses of brachiopod shells. Because of the huge reservoir of carbon in carbonates, also whole rock samples are suitable for stable carbon isotope analyses if they are not altered by meteoric water or by incorporation of re-oxidized organic carbon during diagenesis. There are several possibilities to test the quality of the data: (1) comparison of the ?13C record of whole rock samples with samples from brachiopod shells, (2) with the organic record, (3) analyses of the same time interval in different sections. If the same pattern of isotope data is observed in separa-ted palaeogeographic settings, it is probably caused by a change in the global carbon reservoir. Reliable ?13C data will be presented for the Devonian, Mississippian and Middle to Late Permian. During Pennsylvanian and Early Permian most carbonates were affected by meteoric diagenesis due to the large glacio-eustatic sea level changes of the Permo-Carboniferous glaciation. Long term variations (mean values for 10 Ma) are known from literature. Devonian ?13C values are about 0 to 2 ppm (V-PDB) they increase up to 5 to 6 ppm during the Mississippian - Pennsylvanian transition and drop sharply at the Permian Triassic boundary. The Devonian - Carboniferous trend is probably at least partly due to the evolution of land plants. Short term variations in the range of 0.1 to 1 Ma modify the long term trend significantly. Large positive excursions of ?13C up to 5 or 6 ppm are known from the Silurian - Devonian boundary and during the Middle Tournaisian of Laurentia and Europe. Many positive excursions of a magnitude of 2 to 3 ppm are observed, some are verified worldwide as for instance at the Frasnian - Famennian boundary which coincides with one of the largest extinction events in earth history. Short time variations in the isotopic composition of global CO_2 are controlled by the partitioning between the organic and inorganic reservoir during sedimentation. Concomittants are often sea level changes and/or other geologial and biological events.

Buggisch, W.

2003-04-01

213

Numerical modeling of regional ground-water flow in the deep-basin brine aquifer of the Palo Duro Basin, Texas Panhandle  

International Nuclear Information System (INIS)

Bedded Permian-age evaporite sequences in the Palo Duro Basin are being considered for a permanent nuclear waste repository by the U.S. Department of Energy. The purpose of this modeling study is to provide an understanding of regional ground-water flow in the formations beneath the Permian evaporite section. From this understanding, more detailed, smaller scale studies can be designed. This study is also intended to provide a better understanding of the boundary conditions and permeabilities of the aquifer and aquitard system as well as provide estimates of ground-water travel times across the basin. Numerical simulations were made of the Wolfcamp aquifer modeled as a single layer and of the entire Deep-Basin Brine aquifer system, including the Wolfcamp aquifer, modeled as a single layer

214

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

215

Area environmental characterization report of the Dalhart and Palo Duro basins in the Texas Panhandle. Volume I. Dalhart 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 highly variable prcipitation. Restrictive dispersion conditions are infrequent. National ambient secondary air quality standards for particuecondary air quality standards for particulates are being exceeded in the area, largely because of fugitive dust, although there are some particulate point sources

216

The Tethyan plume: geochemical diversity of Middle Permian basalts from the Oman rifted margin  

Science.gov (United States)

According to palinspastic reconstructions, the Neo-Tethys opening took place during the Permian between the Cimmerian fragments in the north and the Indo-Arabian margin in the south. Igneous remnants of this opening are exposed in Oman within either the Hawasina nappes or the para-autochtonous Arabian platform exposed in the Saih Hatat tectonic window. They consist predominantly of pillowed basaltic flows among which three groups have been distinguished. Group 1 is tholeiitic and characterized by low TiO 2 and incompatible trace element contents, and a large range of ?Nd i values. Group 1 basalts are associated with distal sediments and plot near the boundary of or within the MORB field in the Pb-Pb correlation diagrams and between the MORB and Bulk Silica Earth (BSE) fields in ?Nd i-( 206Pb/ 204Pb) i diagram. Group 2 basalts are alkaline and differ from Group 1 ones by their higher TiO 2, La and Nb contents, and lower and more homogeneous ?Nd i values (+3 to +5). Group 2 volcanics are similar to alkali basalts from oceanic islands and share with Group 1 similar initial Pb ratios. Group 3 consists of tholeiitic and alkali basalts which are interbedded either with carbonate-platform sediments from the Saih Hatat window or with distal sediments from the Hawasina Nappes. This group differs from Groups 1 and 2 by its low to negative ?Nd i (+1.6 to -2). Group 1 likely derived from the mixing of depleted and enriched sources while Group 2 derived exclusively from an enriched source. There is no indication that continental crust was involved in the genesis of both Groups 1 and 2. In contrast, the low to negative ?Nd i values of Group 3 suggest that the magmas of this group were contaminated by the Arabian continental crust during their ascent. The geochemical features of the Middle Permian plume-related basalts suggest thus that the basement of the Hawasina basin was not genuine oceanic crust but either the thinned Arabian rifted continental margin or the continent-ocean transition zone of the Neo-Tethys.

Lapierre, H.; Samper, A.; Bosch, D.; Maury, R. C.; Béchennec, F.; Cotten, J.; Demant, A.; Brunet, P.; Keller, F.; Marcoux, J.

2004-06-01

217

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

218

Provenance analysis of Permian sandstones in the central and southern Da Xing'an Mountains, China: Constraints on the evolution of the eastern segment of the Central Asian Orogenic Belt  

Science.gov (United States)

Modal, chemical and U-Pb zircon data from Permian sandstones in the central and southern Da Xing'an Mountains (eastern Inner Mongolia, China) constrain, for the first time, plate collision processes between the northern margin of the North China craton and the composite Erguna-Xing'an-Songliao block. The study area is located between the Ondor Sum-Xar Moron and Hegenshan suture zones of the eastern segment of the Central Asian Orogenic Belt. Modal and geochemical analyses of Permian sandstones suggest derivation from dissected continental arc and recycled orogenic sources. LA-ICP-MS U-Pb detrital zircon data from sandstones indicate Early Permian to earliest Triassic maximum depositional ages (278 ± 4 Ma to 249 ± 3 Ma). These data also show two uniform age groups of 270-280 Ma and 310-320 Ma, and we interpret their source to be mainly the Sonidzuoqi-Xilinhot-southern Xi Ujimqin magmatic arc in the north (the southern margin of the Xing'an-Erguna block). The sample from the Upper Permian to lowermost Triassic Linxi Formation in the Linxi area also contains zircons with age groups of ~ 1800 Ma and ~ 2500 Ma, consistent with derivation from the northern margin of the North China craton, which lies to the south. Therefore, the collision between the North China craton and the Xing'an-Erguna block began during the deposition of the Linxi Formation, and the final closure of the intervening oceanic basin occurred during ca. Late Permian-earliest Triassic times, forming the Ondor Sum-Xar Moron suture zone.

Han, Guoqing; Liu, Yongjiang; Neubauer, Franz; Genser, Johann; Zhao, Yingli; Wen, Quanbo; Li, Wei; Wu, Linna; Jiang, Xiaoyan; Zhao, Limin

2012-12-01

219

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

220

Evolution of the West Siberian Basin  

Energy Technology Data Exchange (ETDEWEB)

The West Siberian Basin is one of the largest intra-cratonic basins of the world and an important hydrocarbon province of Russia. Perhaps the most important geologic event in Siberia was the emplacement of basalts around {approx} 250Ma (i.e. Permo-Triassic boundary) covering an area of about 5x10{sup 6} km{sup 2}. This volcanism may be responsible for a mass extinction that occurred around Permian-Triassic time. The pre-basaltic rifting event was limited to the north-northeastern sector of the basin. Initial basin wide subsidence took place in the Jurassic as a result of which the western part of Siberia became the West Siberian Basin bounded by uplifts to the east and to the west. One of the surprising aspects of the West Siberian Basin is the abundance of sub-vertical faults believed to be result of strike-slip movement. While intra-plate inversions and fault reactivation structures have been observed in many cratons, sub-vertical faults observed in the West Siberian Basin are unique because of their geometries and abundance. The differentiation between the effects of tectonics and eustasy in cratonic basins is simple-the global eustatic signal is basin-wide with regional and local tectonics playing an overprinting role. Thus, the Middle Jurassic-Turonian 1st, 2nd, and 3rd order cycles in the West Siberian Basin were primarily driven by eustasy. The Middle Jurassic-Turonian series can be subdivided into two second-order and 16 third-order transgressive-regressive cycles (within dataset extent). Fourth-order cycles appear to be controlled by delta shifting. Although extensively studied, a number of fundamental questions regarding the origin and evolution of the West Siberian Basin remain unresolved or poorly documented in the literature. [Author].

Vyssotski, A.V. [Chevron, 1500 Louisiana Street, Houston (United States); Vyssotski, V.N. [TNK-BP, 1 Arbat St, Moscow 119019 (Russian Federation); Nezhdanov, A.A. [OOO TyumenNIIgiprogas, 2 Vorovskogo Str., Tyumen 625019 (Russian Federation)

2006-01-01

 
 
 
 
221

Syndepositional tectonics recorded by soft-sediment deformation and liquefaction structures (continental Lower Permian sediments, Southern Alps, Northern Italy): Stratigraphic significance  

Science.gov (United States)

The Lower Permian succession of the Central Southern Alps (Lombardy, Northern Italy) was deposited in fault-controlled continental basins, probably related to transtensional tectonics. We focussed our study on the stratigraphic record of the Lower Permian Orobic Basin, which consists of a 1000 m thick succession of prevailing continental clastics with intercalations of ignimbritic flows and tuffs (Pizzo del Diavolo Formation, PDV) resting on the underlying prevailing pyroclastic flows of the Cabianca Volcanite. The PDV consists of a lower part (composed of conglomerates passing laterally to sandstones and distally to silt and shales), a middle part (pelitic, with carbonates) and an upper part (alternating sandstone, silt and volcanic flows). Syndepositional tectonics during the deposition of the PDV is recorded by facies distribution, thickness changes and by the presence of deformation and liquefaction structures interpreted as seismites. Deformation is recorded by both ductile structures (ball-and-pillow, plastic intrusion, disturbed lamination, convolute stratification and slumps) and brittle structures (sand dykes and autoclastic breccias). Both the sedimentological features and the geodynamic setting of the depositional basin confidently support the interpretation of the described deformation features as related to seismic shocks. The most significant seismically-induced deformation is represented by a slumped horizon (about 4 m thick on average) which can be followed laterally for more than 5 km. The slumped bed consists of playa-lake deposits (alternating pelites and microbial carbonates, associated with mud cracks and vertebrate tracks). The lateral continuity and the evidence of deposition on a very low-angle surface along with the deformation/liquefaction of the sediments suggest that the slump was triggered by a high-magnitude earthquake. The stratigraphic distribution of the seismites allows us to identify time intervals of intense seismic activity, which correspond to rapid and basin-wide changes in the stratigraphical architecture of the depositional basin and/or to the reprise of the volcanic activity. The nature of the structures and their distribution suggest that the magnitude of the earthquakes responsible for the observed structures was likely higher than 5 (in order to produce sediment liquefaction) and probably reached intensity as high as 7 or more. The basin architecture suggests that the foci of these earthquakes were located close to the fault-controlled borders of the basin or within the basin itself.

Berra, F.; Felletti, F.

2011-04-01

222

Origin of the Early Permian zircons in Keping basalts and magma evolution of the Tarim Large Igneous Province (northwestern China)  

Science.gov (United States)

The Tarim continental flood basalts (CFBs) provide important clues about the genesis and magmatic evolution of the Early Permian Tarim Large Igneous Province (Tarim LIP) in northwestern China. Here we present results of LA-MC-ICPMS Lu-Hf isotope analysis on Early Permian (ca. 290 Ma) zircons extracted from the Tarim CFBs in the Keping area, northwest of the Tarim Basin. Zircons from two sub-groups of Keping basalts (Groups 1a and 1b) have similar Lu-Hf isotopic compositions and exhibit a relatively large range of 176Hf/177Hf ratios between 0.282422 and 0.282568. Their negative ?Hf(t) values (- 6.8-- 1.4) are generally lower than the whole-rock ?Hf(t) values of their host basalts (- 2.8-2.1), and are distinct from other known intrusive rocks (- 0.3-7.1) in the Tarim LIP and their hosted zircons (4.9-8.8). Systematic studies of Hf isotopic data from Tarim and its adjacent regions reveal that these zircons are probably xenocrysts, sourced from coeval igneous rocks in the South Tianshan Orogen (e.g., the Lower Permian Xiaotikanlike Formation volcanic and pyroclastic rock suite). This, together with the presence of Precambrian zircons in Keping basalts, clearly indicates crustal contamination during their eruptions and provides hints about the potential contaminant sources. Geochemical modeling further suggests that the earlier erupted Group 1b basalts experienced more contamination, predominantly by some high Th-U-Pb rock components, most likely from the South Tianshan Orogen. The later erupted Group 1a basalts in the Keping area have been less contaminated with mainly the Tarim Precambrian rocks. Another group of the Tarim CFBs in the Northern Tarim Uplift (Group 2) appears to have undergone negligible crustal contamination but possesses evidence for variable source compositions. The modeling also indicates that the uncontaminated parental magmas of various Tarim LIP rocks (from the picrites and basalts to ultramafic-mafic and syenitic intrusive rocks) exhibit a wide range of ?Nd(t) values (ca. - 5-5), reflecting source isotopic heterogeneity, which may be a consequence of plume-lithosphere interaction during the generation of the Tarim LIP.

Li, Yin-Qi; Li, Zi-Long; Yu, Xing; Langmuir, Charles H.; Santosh, M.; Yang, Shu-Feng; Chen, Han-Lin; Tang, Zhong-Li; Song, Biao; Zou, Si-Yuan

2014-09-01

223

Geochemical evidence from Lower Permian volcanic rocks of northeast New South Wales for asthenospheric upwelling following slab breakoff  

International Nuclear Information System (INIS)

The ca 280 Ma Alum Mountain Volcanics and Werrie Basalt were erupted in northeast New South Wales, Australia, during Early Permian lithospheric extension that separated discrete episodes of subduction of Carboniferous and Late Permian - Triassic age. The Alum Mountain rocks, which are preserved in two major synclines in the southeast Tamworth Belt, are mostly basalt, but andesite and rhyolite are also present. The Werrie Basalt found further north in the Tamworth Belt and in the floor of the Gunnedah Basin is composed mainly of basalt, but includes more evolved rocks in the vicinity of several eruptive centres. The Alum Mountain rocks have REE abundances similar to N-MORB, with flat REE patterns, (La/Sm)N ratios ranging from 0.54 to 1.07, and (La/Yb)N ratios from 0.94 to 2.78, suggesting an origin by large degrees of partial melting of asthenosphere at a depth Nd values, ranging from +2.05 to +6.00, suggesting an asthenospheric origin for these rocks. Spider diagrams show a clear negative Nb anomaly, typical of subduction zones, but LREE/HREE [(La/Sm)N = 1.61 to 2.20; (La/Yb)N = 5.07 to 8.81], Ti/Zr, and Ti/P ratios are close to OIB values. The enriched character of the Werrie Basalt has resulted from either asthenospheric melts being progressively modified during ascent of fractionating magmas through the lithosphere, or by partial melting of a mantle metasomatised by subduction. The presence of a significant depleted-mantle component in the signature of the Lower Permian volcanic rocks indicates rise of the local mantle geotherm to allow extensive melting. We therefore propose a model of asthenospheric upwelling and lateral flow following breakoff of the Carboniferous subducting slab. Our model of asthenospheric convection as derived from eastern Australia suggests a major role for the asthenosphere in subduction zones: not only is the asthenosphere the reservoir from which magmatic arc melts originate, but we surmise that the behaviour of asthenospheric mantle at subduction zones may have far-reaching implications for the overall thermal state of the planet. Copyright (2001) Geological Society of Australia

224

The salt that wasn't there: Mudflat facies equivalents to halite of the Permian Rustler Formation, southeastern New Mexico  

International Nuclear Information System (INIS)

Four halite beds of the Permian Restler Formation in southeastern New Mexico thin dramatically over horst lateral distances to correlative classic (mudstone) beds. The mudstones have long been considered residues after post-burial dissolution (subrosion) of halite, assumed to have been deposited continuously across the area. Hydraulic properties of the Culebra Dolomite Member have often been related to Rustler subrosion. In cores and three shafts at the Waste Isolation Pilot Plant (WIPP), however, these mudstones display flat bedding, graded bedding, cross-bedding, erosional contacts, and channels filled with intraformational conglomerates. Cutans indicate early stages of soil development during subaerial exposure. Smeared intraclasts developed locally as halite was removed syndepositionally during subaerial exposure. The authors interpret these beds as facies formed in salt-pan or hypersaline-lagoon, transitional, and mudflat environments. Halite is distributed approximately as it was deposited. Breccia in limited areas along one halite margin indicates post-burial dissolution, and these breccials are key to identifying areas of subrosion. A depositional model accounts for observed sedimentary features of Restler mudstones. Marked facies and thickness changes are consistent with influence by subsidence boundaries, as found in some modern continental evaporites. A subrosion model accounts for limited brecciated zones along (depositional)halite margins, but bedding observed in the mudstones would not survive 90% reduction in rock volume. Depositional margins for these halite beds will be useful in reconstructing detailed subsidence history of the Late Permian in the northern Delaware Basin, It also no longer is tenable to attribute large variations in Culebra transmissivity to Rustler subrosion

225

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

226

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

Science.gov (United States)

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

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

2004-12-01

227

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

228

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

229

Palaeomagnetism and palaeogeography of Mongolia in the Cretaceous, Permian and Carboniferous—preliminary data  

Science.gov (United States)

The paper reports on the results of palaeomagnetic stability tests of oriented samples of lithologically different types of Cretaceous, Permian and Carboniferous rocks from northern and southern Mongolia. The Permian andesites and tuffites from three localities (Barun Buren, Tel Tin Gol, and Chulut Tsagan Del) have yielded interesting results. Groups of normally and reversely polarized andesite tuffs were found even within a single outcrop by means of thermal field demagnetization and multicomponent analysis of the magnetization. With a view to the number of samples (177) suitable for analysis and the number of localities (9), the reported palaeomagnetic data should be considered as preliminary. The interpreted results indicate a different palaeogeographic evolution of northern and southern Mongolia relative to the Siberian platform and North China in the Permian and Carboniferous. On the other hand, similar apparent polar wander paths for North China (Lin et al., 1985) and the studied regions of northern and southern Mongolia indicate similar palaeogeographic evolution in the Permian to Carboniferous.

Pruner, Petr

1987-07-01

230

Extensive, uplift-related and non-fault-controlled spar precipitation in the Permian Capitan Formation  

Science.gov (United States)

With time, unlithified grains in sediments become cemented and eventually lithified to form sedimentary rocks. Sedimentary rocks of all ages, lithologies and depositional settings exhibit cements. The timing of cementation within a given sedimentary unit, however, is generally poorly constrained. The formation conditions of the youngest of cement generations are particularly difficult to characterize. Typically, traditional carbonate carbon (?13Ccarb) and oxygen (?18Ocarb) isotope analyses are used to characterize precipitation timing and environment. However, ambiguities associated with the interpretation of ?18Ocarb data lead to conflicting hypotheses. The Permian Capitan Formation is one of the most widely studied carbonate sequences and contains extensive calcite cements that have been interpreted to form across a range of diagenetic environments through ?18Ocarb analyses. Here, we present new and previously reported clumped isotope data from calcite spars of Capitan fore-reef slope and equivalent shelf facies (Tansill Formation) in order to constrain mineralization temperatures, provide previously unattainable information concerning precipitation environment, and explore the spatial extent of precipitation events. Spar precipitation temperatures range from ~ 30 to 75 °C and show positive correlation with reconstructed pore water ?18O values, indicating rock-buffered behavior. Evaluation of the data using a simple water-rock model indicates that the fluid(s) involved in diagenesis must have had a significant meteoric component, exhibiting fluid ?18O values approaching - 12‰ (VSMOW). These new data along with previously reported outcrop and core relationships indicate that spar precipitation occurred well after deposition of the Capitan Formation and likely during Tertiary uplift when fluids with such light isotopic signatures would have infiltrated the basin, and not during burial as generally assumed. The meteoric fluids responsible for spar precipitation may have been delivered locally through fracture networks, but also penetrated less fractured facies and produced extensive spar cements.

Loyd, S. J.; Dickson, J. A. D.; Scholle, P. A.; Tripati, A. K.

2013-12-01

231

Lake deposits of moderate salinity as sensitive indicators of lake level fluctuations: Example from the Upper Rotliegend saline lake (Middle-Late Permian, Northeast Germany)  

Science.gov (United States)

The Rotliegend saline lake periodically covered wide areas of the Southern Permian Basin in Northwest Europe during the Permian. The sedimentology, mineralogy and geochemistry of lake deposits were studied to document very high frequency lake level fluctuations and to evaluate their triggers. Increased precipitation and marine ingressions into the basin resulted in lake extension. Increased run-off is documented by intercalated fluvial deposits in low-salinity deposits of the lake. Because lake deposits reflect mainly deposition in relatively wet climate phases, they are not correlatable to halite deposits in other basin areas. Decreased precipitation is followed by shrinkage of the lake, desiccation at its margins, and higher lake salinity due to concentration of the brine. Carbonate and anhydrite contents of lake deposits increased considerably before the areas fell dry, but halite is not preserved in the study area. Falling lake level is also reflected by the occurrence of wave ripples, reflecting decreased water depth and finally by desiccation and formation of evaporite crusts. Not only the mineralogical content, but also the colour of lake claystones changes with varying salinity. Anhydrite- and carbonate-free red claystones were replaced by violet to green and grey anhydritic and calcareous claystone or marls with increasing salinity. The amount of boron adsorbed on illite also corresponds to changes in salinity and can therefore be used as a palaeosalinity indicator. Rare earth element concentrations within lake deposits do not reflect variations in salinity but different palaeogeographical settings. Marine ingressions into the lake are neither reflected by the amount of boron adsorbed onto illite nor by rare earth element contents of the lake deposits. Highly saline deposits are partly characterised by intensive deformation, which can be interpreted as seismites or dissolution breccias.

Legler, B.; Schneider, J. W.; Gebhardt, U.; Merten, D.; Gaupp, R.

2011-03-01

232

Barents Sea crustal architecture and basin development  

Science.gov (United States)

The Barents Sea continental shelf is characterized by a complex tectonic history and thus comprises a wide range of crustal and basin architectures that formed in response to different geological processes. Overlapping Paleozoic orogenies (Timanian, Caledonian, Uralian) preceded multiple rift episodes mainly affecting the western Barents Sea and eventual breakup with Greenland to the west and Lomonosov Ridge to the north. Recent work related to the PETROBAR and BarMod projects has provided new details on basin architecture, tectonic and thermal histories, stratigraphy, paleogeography, paleo-water depths and the role of the basement grain in the structuring of the Barents Sea basins. The eastern Barents Sea comprises a wide and deep sag basin that formed by rapid subsidence in Late Permian-Early Triassic times, most likely in response to basin-forming mechanisms other than rifting. The deep East Barents Sea Basin was filled by thick uppermost Permian and Triassic sediments prograding westwards from uplifted source areas mainly in the SE (Urals). In the western Barents Sea we find more typical rift basins formed in response to at least three major post-Caledonian rift phases: Carboniferous, Late Jurassic-Early Cretaceous, and Late Cretaceous-early Paleogene. The rifting activity migrated westwards through successive tectonic phases. Carboniferous rifting affected the entire western Barents Sea and gave rise to NE-SW to N-S trending horst and graben structures following a Caledonian basement grain. These structures were covered by a regional carbonate platform before renewed faulting affected the SW Barents Sea in Late Permian time. The major prograding system reached the western Barents Sea in earliest Triassic time gradually filling in a regional basin of considerable waterdepths. Late Jurassic-Early Cretaceous oblique extension and formation of the deep SW Barents Sea basins was linked to the North Atlantic-Arctic plate tectonic evolution. Regional uplift associated with the Early Cretaceous High Arctic Large Igneous Province gave rise to a depositional system characterized by north to south progradation covering most of the Barents Sea. Volcanic extrusives are preserved in the northern Barents Sea, mainly on Franz Josef Land and eastern Svalbard, while intrusives are found widespread, particularly in the deep East Barents Sea Basin. A Late Cretaceous-Early Paleogene mega-shear system along the western Barents Sea-Svalbard margin (De Geer Zone) linked rifting, breakup and initial opening of the Norwegian-Greenland Sea and the Arctic Eurasia Basin. Narrow pull-apart basins formed within this dominantly shear system, in particular at a releasing bend in the margin SW of Bjørnøya. A restraining bend SW of Svalbard gave rise to the transpressional Spitsbergen Fold-and-Thrust Belt. Compressional structures of different styles are found widespread in the Barents Sea region. The nature and timing of these are difficult to constrain in many areas due to later uplift and erosion, but we expect that there are different causes and timing involved. At the western margin we see evidence of compressional deformation as young as Miocene in age. The entire Barents Shelf was uplifted and eroded during Neogene time and thick fans of Plio-Pleistocene glacial sediments were formed in front of bathymetric troughs characteristic of both the western and northern Barents Sea. Most of the uplift is closely linked to the glacial erosion, but tectonic uplift occurred prior to the glaciations.

Faleide, J. I.

2012-04-01

233

The Timan-Pechora oil-gas basin: A geological review  

Energy Technology Data Exchange (ETDEWEB)

At the base of the sedimentary section of the Timan-Pechora basin are Late Precambrian rifts, which are filled by unmetamorphosed sedimentary rocks 10 km and more than 10 km thick. The upper parts of these rift deposits have potential for gas. Structurally the Phanerozoic sedimentary fill of the basin is mildly deformed in the west and central parts into several broad depressions and more narrow intervening highs. The eastern part is strongly deformed by overthrusts that were emplaced in the Late Paleozoic in connection with development of the Ural fold belt. Eight oil-gas plays are recognized in the basin: 1-Ordovician-Lower Devonian, 2-Middle Devonian-lower Frasnian, 3-upper Frasnian-Tournaisian, 4-Lower Carboniferous, 5-upper Visean-Lower Permian, 6-Lower Permian, 7-Upper Permian, and 8-Triassic. The promising oil-gas basin is of great interest for global stratigraphy and tectonics as well as for petroleum exploration. 18 refs., 7 figs., 1 tab.

Clarke, J.W. [Geological Survey, Reston, VA (United States)

1994-01-01

234

Structural style and evolution of the Pechora basin, USSR  

Energy Technology Data Exchange (ETDEWEB)

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

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

1991-08-01

235

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

236

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.

237

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

Science.gov (United States)

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

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

2013-04-01

238

Evolution of the Northeast German Basin — inferences from a 3D structural model and subsidence analysis  

Science.gov (United States)

A 3D structural model of the Northeast German Basin was evaluated with special emphasis on its evolution as an intracontinental depression. The study includes investigations on subsidence history and structural setting of the basin. Thickness evolution and calculated tectonic subsidence volumes of Permian to Quaternary sediments in the Northeast German Basin indicate that the subsidence history was related to five stages of basin evolution which differ in their subsidence mechanisms. For the initial rift phase in the Late Carboniferous to Early Permian, a dominant thermal event and subordinate horizontal stresses were indicated by thickness variation evolution and by structural evidence. The main part of basin subsidence occurred in a NW-SE-oriented basin in the subsequent phase of thermal relaxation with maximum subsidence from Early Permian (Rotliegend) to Middle Triassic (Muschelkalk). From Middle Triassic the thermal subsidence pattern was superposed by further tectonic events. In the Middle Triassic regional extension led to a reconfiguration of the southern part of the basin, where new NNE-SSW-trending troughs (Rheinsberg and Gifhorn Troughs) developed. In the Jurassic the northwestern part of the basin was uplifted while in the south the Keuper subsiding areas continued to sink and NW-SE-trending depressions, related to salt margins, became important. Differentiation continued into Cretaceous times when regional compression caused uplift of the southeastern part of the basin and basin margins. A final subsidence phase occurred in the Cenozoic. This was accompanied by intensive salt movement. Recent basin configuration reflects the superposition of structural elements resulting from different evolution stages. The main structural characteristics of the basin are: (1) a vertical tectonic zonation in a pre-Zechstein succession, which lacks significant internal structures, and a strongly deformed post-Zechstein succession, which was decoupled due to the thick Zechstein salt; and (2) a marked asymmetry of the basin with a shallow northern slope and a steep bounding fault at the southern margin (Elbe Fault System). The northwestern part of the basin shows the structural properties of an intracratonic sag basin with persisting subsidence and with minor salt mobilisation. In contrast, initial structures in the southeastern part are strongly overprinted by younger tectonic events including Middle Triassic to Jurassic extension, Late Cretaceous inversion and Late- to post-Cretaceous salt movements. Tectonic elements that deform the whole sedimentary succession are restricted to the basin's southern, eastern and northeastern margins where salt thickness decreases. Combined volumetric and backstripping investigations show that 2/3 of the total subsidence was induced by the sediment load and 1/3 was caused by tectonics. The tectonic subsidence history varies laterally across the basin. While tectonic subsidence curves in the northwestern part of the basin show fast subsidence during the Permian, and Early Triassic decreasing exponentially with time, subsidence curves in the southeastern part indicate repeated tectonic activity. However, the tectonic subsidence volume created during Permian to Late Triassic is significantly higher than the tectonic subsidence during younger phases of basin history.

Scheck, M.; Bayer, U.

1999-11-01

239

Magnetostratigraphy of Permian/Triassic boundary sequences in the Cis-Urals, Russia: No evidence for a major temporal hiatus  

Science.gov (United States)

During the last five years there has been considerable doubt over the age of the continental uppermost Permian Russian stages, the Kazanian and Tatarian. Traditionally they have been regarded as Late Permian but were re-dated as Middle Permian in the 2004 international time scale, despite fossil evidence that the Tatarian, at least, is Late Permian. These debated ages are tested by magnetostratigraphic study of five sections spanning the Permian Triassic Boundary (PTB) of the SE Urals in the Orenburg region of Russia. The Upper Permian and Lower Triassic of this region have a well documented vertebrate fauna whose evolution has a significant bearing on our understanding of the PTB mass extinction event. If the Tatarian is viewed as Mid Permian, then the Late Permian in Russia is marked by a 9-10 Ma stratigraphic gap. The palaeomagnetic data yield a distinct series of polarity zones that provide clear local and regional correlation and are readily tied to a recently compiled global magnetostratigraphic record. On the basis of this correlation the sampled sections span the upper Guadalupian to Induan stages without any obvious break, so confirming the traditional view that the Tatarian is Late Permian in age. Anomalies in the magnetic inclination are consistent with sediment compaction (inclination shallowing, a common phenomenon of red beds) but declination anomalies between these sites and elsewhere in Russia may suggest localised vertical axis rotation.

Taylor, Graeme K.; Tucker, Christopher; Twitchett, Richard J.; Kearsey, Timothy; Benton, Michael J.; Newell, Andrew J.; Surkov, Mikhail V.; Tverdokhlebov, Valentin P.

2009-04-01

240

Middle Permian plume-related magmatism of the Hawasina Nappes and the Arabian Platform: Implications on the evolution of the Neotethyan margin in Oman  

Science.gov (United States)

Permian pillow basalts are commonly found in Oman either at the base of the Hawasina Nappes or within the Arabian Platform successions exposed in the Saih Hatat tectonic window. There is an ongoing debate on whether these lavas include normal mid-oceanic ridge basalts (NMORB) witnessing the Permian opening of the Neotethys or if they are plume-related magmas that are emplaced either on the Arabian Platform or on its thinned continental margin. We sampled these lavas from several paleontologically dated middle Permian sites. Four of them (Buday'ah, Rustaq, Al Ajal, and Wadi Wasit) are located within the Hawasina Nappes and are exposed as thrust slices overlain by the Samail Nappe, and one (Wadi Aday) is within the Arabian Platform units and is exposed in the Saih Hatat window. These lavas are associated with marine sediments deposited in environments ranging from proximal (Saih Hatat, Wadi Wasit, and base of the thrust pile of Al Ajal) to distal (Buday'ah, Rustaq, and top of the Al Ajal pile) with respect to the Arabian Platform. Major and trace element features of the basalts allow two groups to be recognized. Enriched high-Ti basalts similar to alkali basalts from intracontinental traps, rifted continental zones, and oceanic islands are exposed in Wadi Aday, Wadi Wasit, and at the structural base of the Al Ajal pile. Moderately enriched to slightly depleted low-Ti tholeiitic basalt magmas resembling the low-Ti flood basalts and those from seaward dipping reflector sequences are represented in Wadi Al Hulw in Saih Hatat, Buday'ah, Rustaq, and at the top of the Al Ajal thrust pile. Both groups show distinct plume-related trace element signatures, and they do not include typical NMORB. Although emplaced in shallow to deep submarine environments, these basalts provide no direct evidence for a Neotethyan seafloor-spreading event in the Hawasina Basin. Instead, they were likely erupted through the crust of the already rifted and drowned Arabian continental margin. Thus, despite their characteristic plume-related geochemical signatures, the middle Permian basalts from Oman were not likely emplaced during the evolution of a typical volcanic rifted margin. We suggest that they originated from a mantle plume which ascended beneath the Arabian passive margin well after the initiation of seafloor spreading of the Neotethys.

Maury, René C.; BéChennec, FrançOis; Cotten, Joseph; Caroff, Martial; Cordey, Fabrice; Marcoux, Jean

2003-12-01

 
 
 
 
241

Roadian-Wordian (Guadalupian, Middle Permian) global palaeobiogeography of brachiopods  

Science.gov (United States)

A database of 4471 Roadian-Wordian (Guadalupian, Middle Permian) occurrences of 381 brachiopod genera in 44 different operational geographical units (stations) was analyzed by both Q-mode and R-mode quantitative methods. Four distinct brachiopod biogeographical realms and nine provinces, and 11 brachiopod associations are recognized. The Boreal Realm in the Northern Hemisphere includes the Verkolyman Province in the northern and northeastern Siberian Platform and the eastern European Province in the Ural seaway between the European and Siberian platforms. Both provinces are characterized by containing typical Boreal cold-water brachiopod associations. The Gondwanan Realm in the south also includes two provinces. The Austrazean Province in eastern Australia and New Zealand is probably the most stable province throughout the Permian and characterized by typical Gondwanan brachiopod associations. The Westralian Province centered in Western Australia is also characterized by typical Gondwanan brachiopods, but also demonstrates biogeographical links with the Tethyan stations. The Palaeoequatorial Realm located mainly in the palaeotropical zone contains highly diverse and abundant brachiopod faunas. Two regions/subrealms and four provinces are recognized within this realm. The North America Subrealm contains a distinct Grandian Province characterized by many endemic brachiopod genera and a few cold-water genera. East-central Alaska and Yukon Territory may constitute another brachiopod province. All the stations in the Tethyan Ocean (both Palaeotethys and Neotethys) constitute a distinct Asian-Tethyan Region/Subrealm and incorporate three different provinces. The Cathaysian Province is comprised of the stations in South China and its surrounding terranes/blocks and a few stations in the northern and western margin of the Palaeotethys. Two transitional provinces (Sino-Mongolian-Japanese Province and Cimmerian Province) in the northern and southern temperate zones are also recognizable. The brachiopod fauna from the Mino Belt in Japan is well distinguished from those from other regions, and is hence assigned to the palaeoceanic Panthalassan Realm. Principal coordinates analysis and minimum spanning tree analysis suggest that a latitude-related thermal gradient was the major control for the palaeobiogeography of Roadian-Wordian global brachiopod faunas and for the latitudinal of pattern of decreasing brachiopod generic diversities from the equator to the poles. In addition, geographic separation and oceanic currents may also have played some role in the spatial distribution of brachiopods during Roadian-Wordian times.

Shen, Shu-zhong; Xie, Jun-fang; Zhang, Hua; Shi, G. R.

2009-02-01

242

Geochemical evidence from bio-apatite for multiple oceanic anoxic events during Permian-Triassic transition and the link with end-Permian extinction and recovery  

Science.gov (United States)

A detailed, 20 myr redox history of Permian to Triassic oceans (Changhsingian to Carnian stages) has been constructed using Ce-anomaly (?Ce) and Th/U ratios from conodont albid crown apatite material. The results show that the well-established phenomenon of intense ocean anoxia (coincident with the end-Permian mass extinction) is faithfully recorded in conodont ?Ce and Th/U data. Extending this conodont redox record shows that end-Permian anoxia persisted possibly into the earliest Dienerian Stage and that two intense oceanic anoxic events also occurred later in the Early Triassic (earliest Smithian-earliest Spathian, and middle Spathian), followed by a weaker manifestation of anoxia in the Anisian Stage, seen in ?Ce data. Marine benthic radiation, following the end-Permian mass extinction, began after the Smithian-earliest Spathian anoxic event suggesting a suppression of evolution prior to this due to these inimical conditions. The failure of the middle Spathian anoxic event to retard the evolutionary rebound implies shallow shelf seas remained well ventilated at this time even if the oceans did not. Other attributes of the Early Triassic record also closely coincide with redox fluctuations: phases of anoxia intensification saw the proliferation of microbial carbonates and major negative carbon isotope swings that can be attributed to chemocline shallowing causing alkalinity pulses and enrichment in light, remineralised carbon and/or indicate a trigger meachnaims related to increased fluxes of light C from Siberian volcanic sources.

Song, Haijun; Wignall, Paul B.; Tong, Jinnan; Bond, David P. G.; Song, Huyue; Lai, Xulong; Zhang, Kexin; Wang, Hongmei; Chen, Yanlong

2012-11-01

243

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

244

Uplift and Erosion in the Northern Al Kufrah Basin (Southeast Libya)  

Science.gov (United States)

The Al Kufrah Basin forms part of the North African continental basin system. While neighbouring basins (e.g. Murzuq Basin, Sirt Basin) are proven petroleum provinces, the Al Kufrah Basin is still in an early stage of exploration. This study combines outcrop studies from the northern basin margin (Jabal Az Zalmah) and the eastern basin margin (Jabal Azbah) with subsurface data in a regional analysis of the key episodes of uplift and erosion in the Al Kufrah Basin. The understanding of the burial and exhumation history of a sedimentary basin is an important parameter for modelling source rock maturation and contributes thus to the evaluation of the hydrocarbon potential. In a first approach the amount of net erosion is estimated using geometrical reconstructions along two perpendicular cross-sections, based on interpretation of 2D-seimic data. In a second step the resulting net erosion map is integrated with three different analytical methods: (1) Shale compaction analyses (based on outcrop samples and well logs), (2) sandstone diagenesis analyses (based on outcrop samples) and (3) apatite fission track analyses (based on outcrop samples). Several erosional events are documented in the Palaeozoic stratigraphic record of the Al Kufrah Basin. The major episodes of regional Palaeozoic uplift and erosion occurred in Late Silurian - Early Devonian and in Late Carboniferous - Early Permian ("Hercynian event"). For both episodes a general southward increase in uplift and erosion has been estimated from integrated analyses of seismic and outcrop data. The northern flank of the basin including the Jabal Az Zalmah outcrop area does not appear to have been subjected to major uplift and erosion during these two Palaeozoic events. Maximum burial was reached during the Mesozoic after deposition of Late Permian - Early Cretaceous (?) continental sandstones. The most important episode of uplift and erosion occurred after the Early Cretaceous (?) sedimentation, leading to net erosion of about 3.5 km at the northern basin margin (Jabal Az Zalmah) and about 2.5 km at the eastern basin margin (Jabal Azbah). Most likely this event occurred in Middle - Late Cretaceous, but a Tertiary age cannot be ruled out. This late phase of major uplift and erosion in the north of the basin resulted in the separation of the Al Kufrah Basin from the Sirt Basin to the north. Hence, the present day geometry of the basin was formed in a very late stage of the basin evolution. The uplift and erosion history in the Al Kufrah Basin can not be linked directly to tectonic events, as large scale faulting is not related to the present day basin boundaries.

Gröger, H. R.; Bjørnseth, H. M.; Higgins, S.; Vandré, C.; Walderhaug, O.; Geiger, M.

2009-04-01

245

Preservation of high primary porosity in Paleozoic crinoidal and bioclastic grainstones: Mississippian and Permian subsurface examples from western Canada and Texas  

Energy Technology Data Exchange (ETDEWEB)

Limestone reservoirs with anomalously high porosity and permeability exist in several Paleozoic basinal settings in western North America. They are commonly either crinoidal or bioclastic grainstones that escaped the varied diagenetic environments that most carbonate shelves and slopes experience during sea-level fluctuations. Thus, these diagenetically 'conservative' settings can preserve most of the primary depositional porosity in calcarenites because of sedimentation and burial within normal marine basinal waters. These excellent reservoirs are often encased in deep marine, highly organic shales which may serve as both source rock and seal. Several subsurface examples of remarkable primary porosity occur within Mississippian Waulsortian buildups of western Canada and north-center Texas. Buildups within the Pekisko Formation of Alberta, for instance, contain abundant flanking crinoidal/bryozoan grainstones with up to 25% primary porosity and 10 d permeability. Muddy core facies with productive flank and capping calcarenites are up to 300 ft (90 m) thick and 600-1,200 ft (182-364 m) in diameter. The Bowar 'reef complex' in the Chappel Formation of Stephens County, Texas (2.6 MMBO to date) is similar in many respects to the Canadian buildups. Diagenetic 'conservatism' has also promoted excellent reservoir quality within the outer slope to basinal lower Permian bioclastic grain-flow deposit ('Wolfcamp detrital') plays of the eastern Midland basin where significant diagenesis was arrested after basinal deposition. Interpretations of these examples based upon core and outcrop control provide analogs for future exploration and exploitation in highly porous basinal carbonate reservoirs.

Eby, D.E. (Marathon Oil Co., Littleton, CO (United States)); Kirkby, K.C. (Univ. of Wisconsin, Madison (United States))

1991-03-01

246

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.

2013-06-01

247

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.

248

Simulated warm polar currents during the middle Permian  

Energy Technology Data Exchange (ETDEWEB)

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

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

2001-05-01

249

Diagenesis of Permian alluvial fan deposits of Northern Switzerland  

International Nuclear Information System (INIS)

Fine-grained sandstones of Permian alluvial fan deposits from three Nagra boreholes (Weiach, Riniken, Kaisten) and an exploration well, drilled at Wintersingen are clast supported, moderately sorted arkosic greywackes containing typically 2-20 % clayey matrix. Petrographic studies indicate that the origin of this clayey matrix is postdepositional. Mechanical infiltration of fines and diagenetic reddening of detrital and authigenic iron oxides are the earliest recorded events. Additionally, nodular calcites of calcrete origin and fibrous illitic clays are also ascribed to the eogenetic environment. The present strong compaction fabric results from general lack of eogenetic framework supporting cements. During mesogenesis, secondary porosity was generated through partial removal of early calcite. At the same time, a first generation of syntaxial quartz cementation and a subsequent fibrous illite authigenesis took place. Leaching of detrital K-feldspars post-dating compaction is recorded throughout the studied boreholes. The following burial diagenetic events differ between the various boreholes: in Weiach and Wintersingen kaolinite, illite, prismatic quartz and ankerite/siderite are recorded; in Riniken K-feldspar, illite, prismatic quartz and dolomite developed; whilst in Kaisten K-feldspar and microcrystalline quartz-cement dominate. These differences reflect the chemistry, pH and ionic strength of the pore fluids. Filling of veins by dolomite/ankerite, iron-rich and subsequent iron-poor calcite is the latest recorded event. (author) 21 refs., 10 figs., 1 tab

250

Chemostratigraphy and the composition of oils in the Perth Basin, Western Australia  

Energy Technology Data Exchange (ETDEWEB)

Perth Basin is a deep and linear trough extending over 1,000 km from Geraldton in the north to the south coast of WA. This paper describes a study which was conducted to test the proposition that a combined isotopic and molecular approach could effectively differentiate Paleozoic and Mesozoic petroleum deposits of the Perth Basin and correlate them with feasible source facies. Source evaluation and n-alkaline isotopic analyses of organic carbon through the Kockatea Shale in BMR-10 were conducted to evaluate facies variation within the basal Triassic section. In Woodada-2, an attempt was made to resolve the apparent dating problem in the Late Permian to Early Triassic succession using isotopic and chemical analysis and comparing these data with paleontological information. Perth Basin oils and condensates show a variety of definitive and interesting compositional features. Light carbon isotopic values characteristic of Early Triassic organic matter are translated to the n-alkanes in a family of oils from the Perth Basin. Biomarker evidence also confirms that the basal section of the marine Kockatea Shale is the source of these oils. Oils from terrestrial Jurassic source rocks have heavier carbon isotopic values for their n-alkanes and contain bicadinanes, with resinous flowering plants. This study suggest that the combined use of carbon isotopic signatures and diagnostic bio markers will be a valuable correlation tool in other Australian petroleum provinces and particularly on the Northwest Shelf where potential source rocks of Triassic and Jurassic age have been identified. Isotopic analysis of kerogens from Core-1, Woodada-2, shows a sharp isotopic excursion at 2,293 m which is suggestive of a contact between Permian and Triassic sediments. Abruptness of the shift indicates that a significant amount section is missing. However, a Permian-Triassic contact cannot be unambiguously assigned unless further work uncovers diagnostic Permian fossils below the excursion.

Summons, R.E.; Boreham, C.J.; Foster, C.B.; Murray, A.P. [Australian Geological Survey Organisation, Canberra, ACT (Australia); Gorter, J.D. [Hardy Petroleum Ltd., West Perth, WA (Australia)

1995-12-31

251

Application of Markov chain and entropy analysis to lithologic succession - an example from the early Permian Barakar Formation, Bellampalli coalfield, Andhra Pradesh, India  

Energy Technology Data Exchange (ETDEWEB)

A statistical approach by a modified Markov process model and entropy function is used to prove that the early Permian Barakar Formation of the Bellampalli coalfield developed distinct cyclicities during deposition. From results, the transition path of lithological states typical for the Bellampalli basin is as: coarse to medium-grained sandstone, interbedded, ne-grained sandstone/shale, shale, coal and again shale. The majority of cycles are symmetrical but asymmetrical cycles are present as well. The chi-square stationarity test implies that these cycles are stationary in space and time. The cycles are interpreted in terms of in-channel, point bar and overbank facies association in a fluvial system. The randomness in the occurrence of facies within a cycle is evaluated in terms of entropy, which can be calculated from the Markov matrices. Two types of entropies are calculated for every facies state; entropy after deposition E(post) and entropy before deposition E(pre), which together form entropy set; the entropy for the whole system is also calculated. These values are plotted and compared with Hattori's idealized plots, which indicate that the sequence is essentially a symmetrical cycle (type-B of Hattroi). The symmetrical cyclical deposition of early Permian Barakar Formation is explained by the lateral migration of stream channels in response to varying discharge and rate of deposition across the alluvial plain. In addition, thinning upward cycles in the upper part enclosing thick beds of fine clastics, as well as coal may represent differential subsidence of depositional basin.

Tewari, R.C.; Singh, D.P.; Khan, Z.A. [Sri JNPG College, Lucknow (India). Dept. of Geology

2009-10-15

252

Silicified wood from the Permian and Triassic of Antarctica: Tree rings from polar paleolatitudes  

Science.gov (United States)

The mass extinction at the Permian-Triassic boundary produced a floral turnover in Gondwana in which Paleozoic seed ferns belonging to the Glossopteridales were replaced by corystosperm seed ferns and other seed plant groups in the Mesozoic. Secondary growth (wood production) in both plant groups provides information on plant growth in relation to environment in the form of permineralized tree rings. Techniques utilized to analyze extant wood can be used on fossil specimens to better understand the climate from both of these periods. Late Permian and early Middle Triassic tree rings from the Beardmore Glacier area indicate an environment where extensive plant growth occurred at polar latitudes (~80–85°S, Permian; ~75°S, Triassic). A rapid transition to dormancy in both the Permian and Triassic woods suggests a strong influence of the annual light/dark cycle within the Antarctic Circle on ring production. Latewood production in each ring was most likely triggered by the movement of the already low-angled sun below the horizon. The plants which produced the wood have been reconstructed as seasonally deciduous, based on structural and sedimentologic evidence. Although the Late Permian climate has been reconstructed as cold temperate and the Middle Triassic as a greenhouse, these differences are not reflected in tree ring anatomy or wood production in these plant fossils from the central Transantarctic Mountains.

Ryberg, P.E.; Taylor, E.L.

2007-01-01

253

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

254

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

255

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.

2004-03-01

256

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

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

257

Petroleum source rock potential and thermal maturity, Palo Duro Basin, Texas  

Energy Technology Data Exchange (ETDEWEB)

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 the basin. Pennsylvanian and Lower Permian (Wolfcampian) basinal shales contain up to 2.4% TOC and are fair to very good source rocks. Kerogen color and vitrinite reflectance, which indicate maximum paleotemperatures, were analyzed in all samples containing greater than 0.5% TOC. Pennsylvanian and Wolfcampian kerogen is yellow orange to orange, an indication that temperatures were sufficiently high to begin to generate hydrocarbons from lipid-rich organic material. Palo Duro Basin samples have a broad range of vitrinite reflectance values, but populations with the lowest reflectance probably indicate the true temperatures that were reached in the basin. Average reflectance in representative Pennsylvanian vitrinite is 0.52%; in Wolfcampian samples the average reflectance is 0.48%. These values are consistent with kerogen color and suggest that basinal source rocks may have begun to generate hydrocarbons.

Dutton, S.P.

1980-01-01

258

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

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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

259

Late Triassic volcanic activity in South-East Asia: New stratigraphical, geochronological and paleontological evidence from the Luang Prabang Basin (Laos)  

Science.gov (United States)

In South-East Asia, sedimentary basins displaying continental Permian and Triassic deposits have been poorly studied. Among these, the Luang Prabang Basin (North Laos) represents a potential key target to constrain the stratigraphic and structural evolutions of South-East Asia. A combined approach involving sedimentology, palaeontology, geochronology and structural analysis, was thus implemented to study the basin. It resulted in a new geological map, in defining new formations, and in proposing a complete revision of the Late Permian to Triassic stratigraphic succession as well as of the structural organization of the basin. Radiometric ages are used to discuss the synchronism of volcanic activity and sedimentation. The Luang Prabang Basin consists of an asymmetric NE-SW syncline with NE-SW thrusts, located at the contact between Late Permian and Late Triassic deposits. The potential stratigraphic gap at the Permian-Triassic boundary is therefore masked by deformation in the basin. The Late Triassic volcaniclastic continental deposits are representative of alluvial plain and fluvial environments. The basin was fed by several sources, varying from volcanic, carbonated to silicic (non-volcanic). U-Pb dating of euhedral zircon grains provided maximum sedimentation ages. The stratigraphic vertical succession of these ages, from ca. 225, ca. 220 to ca. 216 Ma, indicates that a long lasting volcanism was active during sedimentation and illustrates significant variations in sediment preservation rates in continental environments (from ˜100 m/Ma to ˜3 m/Ma). Anhedral inherited zircon grains gave older ages. A large number of them, at ca. 1870 Ma, imply the reworking of a Proterozoic basement and/or of sediments containing fragments of such a basement. In addition, the Late Triassic (Carnian to Norian) sediments yielded to a new dicynodont skull, attributed to the Kannemeyeriiform group family, from layers dated in between ˜225 and ˜221 Ma (Carnian).

Blanchard, Sébastien; Rossignol, Camille; Bourquin, Sylvie; Dabard, Marie-Pierre; Hallot, Erwan; Nalpas, Thierry; Poujol, Marc; Battail, Bernard; Jalil, Nour-Eddine; Steyer, Jean-Sébastien; Vacant, Renaud; Véran, Monette; Bercovici, Antoine; Diez, José Bienvenido; Paquette, Jean-Louis; Khenthavong, Bounxou; Vongphamany, Sotsy

2013-07-01

260

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

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

Crasquin Sylvie

2010-01-01

 
 
 
 
261

The western basins : relative economics and supply potential : three short stories  

International Nuclear Information System (INIS)

A review of the major producing oil and gas basins of the Rocky Mountains, San Juan and Permian basins was presented. This paper dealt with how much gas is available and at what cost given the technical challenges associated with extraction. It was predicted that the historical and projected gas demand patterns as well as new pipeline capacity expansions will impact the basis. This paper referred to the Dynegy Deal (market power), the Basis Squash (pipeline expansions) and the Power River Bomb (significant new production). 4 tabs., 5 figs

262

Using conodont elements to distinguish Permian-Triassic boundary disconformity near Haftad Gholleh, central Iran  

Scientific Electronic Library Online (English)

Full Text Available SciELO Colombia | Language: English Abstract in spanish El presente estudio se enfoca en la estatigrafía del Límite Pérmico-Triásico en el área de Haftad Gholleh, al este de Arak y al norte de Mahallat, centro de Irán. Este límite de discordancia erosiva, al igual que en otras secuencias iraníes relacionadas al período Pérmico, contiene calizas dolomías, [...] esquistos y areniscas discordantes localizadas debajo de la secuencia Triásica. En una medida estratigráfica detallada del área de estudio se encontraron conodontas del Límite Pérmico-Triásico (PTB, por sus siglas en inglés). Se reconocieron tres áreas de conodontas, lo que ubica esta sección del PTB como bioestatigráfica precisa. Una de las secuencias superiores del Pérmico pertenece al período Guadalupiense. La secuencia Triásica consiste en calizas con capas vermiculitas coloreadas de esquisto que pertenecen al período Triásico temprano. La discordancia del Límite Pérmico Triásico, entonces, representa un lapso cercano a los 10 millones de años. Abstract in english The present study focuses on the stratigraphy of the Permian-Triassic boundary in the Haftad Gholleh area in eastern Arak and north of Mahallat,located in central Iran. This boundary of erosional unconformity or disconformity and as in other Iranian sequences related to the Permian period, contains [...] dolomitic limestone and shale and sandstone disconformably located below the Triassic sequence. A detailed measured stratigraphic section has provided conodonts from the Permian-Triassic boundary (PTB) sequences in the area being studied. Three conodont areas have been recognied which place the PTB in this section by precise biostratigraphy. One of the most upper Permian sequences belongs to the Guadalupian period. The Triassic sequence consists of vermiculate limestone layers with coloured shale inter beds belonging to the Early Triassic period; unconformity at the Permian-Triassic boundary therefore represents a hiatus of about 10 million years.

Mostafa, Yousefirad; Somayeh, Ghanbari; Mahnaz, Parvanehnejad Shirazi.

2013-06-01

263

Tectonic rotations south of the Bohemian Massif from palaeomagnetic directions of Permian red beds in Hungary  

Science.gov (United States)

Palaeomagnetic studies were carried out in Permian red beds of the Balaton Highlands, the Mecsek Mountains and the Bu??kk Mountains of Hungary. Statistically well defined directions were obtained from six localities in the Balaton Highlands and two localities in the Mecsek Mountains. No meaningful results were obtained from the Bu??kk Mountains. Three magnetic components were identified from red beds of the Balaton Highlands: (1) in haematite with a very high unblocking temperature (700??C), interpreted as a Permian magnetization (Dc= 79??, Ic=-11??, k = 24, ??95 = 13.6 ??), in six samples from three beds in a single locality (2) a secondary but ancient component residing mainly inmaghemite (D = 314??, I = 49??, k = 48, ??95 = 10.0??), in 84 samples from six localities with a within-locality scatter increasing on unfolding; and (3) a direction parallel to the present field (D = 7??, I = 62??, k = 46, ??95 = 7.7 ??), in nine samples from a single locality. For the Balaton Highlands, the component 1 direction agrees with directions obtained from Permian red beds and volcanics in the eastern part of the Southern and Eastern Alps and the Inner West Carpathians. All show large, apparent rotations relative to stable Europe since the Permian. Component 2 is of post-folding (post-Aptian) age. Its direction agrees with known Late Cretaceous directions from the Transdanubian Central Mountains, which also show significant counterclockwise rotation relative to stable Europe. The characteristic magnetization for the Mecsek Mountains resides in haematite and may be primary. The directions indicate only a slight net counterclockwise rotation of the Mecsek Mountains with respect to stable Europe since the Permian. ?? 1987.

Marton, E.; Elston, D.P.

1987-01-01

264

Using conodont elements to distinguish Permian-Triassic boundary disconformity near Haftad Gholleh, central Iran  

Scientific Electronic Library Online (English)

Full Text Available SciELO Colombia | Language: English Abstract in spanish El presente estudio se enfoca en la estatigrafía del Límite Pérmico-Triásico en el área de Haftad Gholleh, al este de Arak y al norte de Mahallat, centro de Irán. Este límite de discordancia erosiva, al igual que en otras secuencias iraníes relacionadas al período Pérmico, contiene calizas dolomías, [...] esquistos y areniscas discordantes localizadas debajo de la secuencia Triásica. En una medida estratigráfica detallada del área de estudio se encontraron conodontas del Límite Pérmico-Triásico (PTB, por sus siglas en inglés). Se reconocieron tres áreas de conodontas, lo que ubica esta sección del PTB como bioestatigráfica precisa. Una de las secuencias superiores del Pérmico pertenece al período Guadalupiense. La secuencia Triásica consiste en calizas con capas vermiculitas coloreadas de esquisto que pertenecen al período Triásico temprano. La discordancia del Límite Pérmico Triásico, entonces, representa un lapso cercano a los 10 millones de años. Abstract in english The present study focuses on the stratigraphy of the Permian-Triassic boundary in the Haftad Gholleh area in eastern Arak and north of Mahallat,located in central Iran. This boundary of erosional unconformity or disconformity and as in other Iranian sequences related to the Permian period, contains [...] dolomitic limestone and shale and sandstone disconformably located below the Triassic sequence. A detailed measured stratigraphic section has provided conodonts from the Permian-Triassic boundary (PTB) sequences in the area being studied. Three conodont areas have been recognied which place the PTB in this section by precise biostratigraphy. One of the most upper Permian sequences belongs to the Guadalupian period. The Triassic sequence consists of vermiculate limestone layers with coloured shale inter beds belonging to the Early Triassic period; unconformity at the Permian-Triassic boundary therefore represents a hiatus of about 10 million years.

Mostafa, Yousefirad; Somayeh, Ghanbari; Mahnaz, Parvanehnejad Shirazi.

265

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

Science.gov (United States)

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

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

2012-10-01

266

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

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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

267

Microbialites and global environmental change across the Permian-Triassic boundary: a synthesis.  

Science.gov (United States)

Permian-Triassic boundary microbialites (PTBMs) are thin (0.05-15 m) carbonates formed after the end-Permian mass extinction. They comprise Renalcis-group calcimicrobes, microbially mediated micrite, presumed inorganic micrite, calcite cement (some may be microbially influenced) and shelly faunas. PTBMs are abundant in low-latitude shallow-marine carbonate shelves in central Tethyan continents but are rare in higher latitudes, likely inhibited by clastic supply on Pangaea margins. PTBMs occupied broadly similar environments to Late Permian reefs in Tethys, but extended into deeper waters. Late Permian reefs are also rich in microbes (and cements), so post-extinction seawater carbonate saturation was likely similar to the Late Permian. However, PTBMs lack widespread abundant inorganic carbonate cement fans, so a previous interpretation that anoxic bicarbonate-rich water upwelled to rapidly increase carbonate saturation of shallow seawater, post-extinction, is problematic. Preliminary pyrite framboid evidence shows anoxia in PTBM facies, but interbedded shelly faunas indicate oxygenated water, perhaps there was short-term pulsing of normally saturated anoxic water from the oxygen-minimum zone to surface waters. In Tethys, PTBMs show geographic variations: (i) in south China, PTBMs are mostly thrombolites in open shelf settings, largely recrystallised, with remnant structure of Renalcis-group calcimicrobes; (ii) in south Turkey, in shallow waters, stromatolites and thrombolites, lacking calcimicrobes, are interbedded, likely depth-controlled; and (iii) in the Middle East, especially Iran, stromatolites and thrombolites (calcimicrobes uncommon) occur in different sites on open shelves, where controls are unclear. Thus, PTBMs were under more complex control than previously portrayed, with local facies control playing a significant role in their structure and composition. PMID:22077322

Kershaw, S; Crasquin, S; Li, Y; Collin, P-Y; Forel, M-B; Mu, X; Baud, A; Wang, Y; Xie, S; Maurer, F; Guo, L

2012-01-01

268

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

269

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

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

Marie-Beatrice FOREL

2012-08-01

270

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1998-07-01

271

Restoration of geometry and emplacement mode of the Permian mafic dyke swarms in Keping and its adjacent areas of the Tarim Block, NW China  

Science.gov (United States)

The Permian mafic dyke swarms are widely distributed in the Tarim Block, East Tianshan and the western Junggar Block in northwestern China. These mafic dyke swarms, together with coeval basalts, mafic-ultramafic intrusions and A-type granitic plutons, constitute the Permian Tarim large igneous province (LIP), which is considered to be mantle plume-derived. In this study, multi-source high-resolution remote sensing images are used to identify the geometry and emplacement mode of the mafic dykes, sills and flood basalts in Keping and its adjacent areas including Bachu (northwestern Tarim Block), Beishan and Kuluketag (northeastern Tarim Block) and Kelamyi (western Junggar Block). Structural analysis and paleomagnetic results are used to restore the primary geometry of the mafic dykes. The results indicate that the lengths and thicknesses among a total of 117 extracted mafic dykes in Keping follow negative exponent size distributions. The mafic dykes have a mean thickness of 3.8 m with a maximum of 21.4 m. The length of unconnected mafic dyke segments ranges from 0.127 km to 17.1 km, with an arithmetic length of 1.8 km. The restoration of geometry of the mafic dykes indicates that the Permian mafic dyke swarms in Keping may have extended as far as 61-69 km along a primary orientation of about N320°W, and the flood basalts of the Tarim LIP may have extended to Keping so that the areal extent of the Tarim LIP could be enlarged for about 12,000 km2 compared with that originally reported (about 250,000 km2). The geometric features of the mafic dyke swarms in Keping and its adjacent areas are different from those of the giant radiating dyke swarms due to radial fractures associated with domal uplift. The mafic dyke swarms and sills in the Tarim LIP make up the plumbing system of the mantle plume. Accompanied by the upwelling of mantle plume, many eruptive centers and regional dykes are generated in Beishan, East Tianshan and Tarim basin. The flood basalts in Keping are fissure-type, which may have been fed by magma conduits from the plume center; whereas in Bachu, the central volcanic eruption is dominant.

Chen, Ning-hua; Dong, Jin-jin; Yang, Shu-feng; Chen, Jian-yu; Li, Zi-long; Ni, Ni-na

2014-09-01

272

Water-rock-CO2 interactions in saline aquifers aimed for carbon dioxide storage: Experimental and numerical modeling studies of the Rio Bonito Formation (Permian), southern Brazil  

International Nuclear Information System (INIS)

Mineral trapping is one of the safest ways to store CO2 underground as C will be immobilized in a solid phase. Carbon dioxide will be, therefore, sequestered for geological periods of time, helping to diminish greenhouse gas emissions and mitigate global warming. Although mineral trapping is considered a fairly long process, owing to the existence of kinetic barriers for mineral precipitation, it has been demonstrated both experimentally and by numerical modeling. Here the results of experimental and numerical modeling studies performed in sandstones of the saline aquifer of the Rio Bonito Formation, Parana Basin, are presented. The Rio Bonito Formation consists of paralic sandstones deposited in the intracratonic Parana Basin, southern Brazil, during the Permian (Artinskian-Kungurian). These rocks have the largest potential for CO2 storage because of their appropriated reservoir quality, depth and proximity to the most important stationary CO2 sources in Brazil. Here it is suggested that CO2 can be permanently stored as carbonates as CO2 reacts with rocks of the Rio Bonito Formation and forms CaCO3 at temperatures and pressures similar to those encountered for CO2 storage in geological formations. Results of this work will be useful for studies of partitioning mechanisms for C trapping in CO2 storage programs.

273

Water-rock-CO{sub 2} interactions in saline aquifers aimed for carbon dioxide storage: Experimental and numerical modeling studies of the Rio Bonito Formation (Permian), southern Brazil  

Energy Technology Data Exchange (ETDEWEB)

Mineral trapping is one of the safest ways to store CO{sub 2} underground as C will be immobilized in a solid phase. Carbon dioxide will be, therefore, sequestered for geological periods of time, helping to diminish greenhouse gas emissions and mitigate global warming. Although mineral trapping is considered a fairly long process, owing to the existence of kinetic barriers for mineral precipitation, it has been demonstrated both experimentally and by numerical modeling. Here the results of experimental and numerical modeling studies performed in sandstones of the saline aquifer of the Rio Bonito Formation, Parana Basin, are presented. The Rio Bonito Formation consists of paralic sandstones deposited in the intracratonic Parana Basin, southern Brazil, during the Permian (Artinskian-Kungurian). These rocks have the largest potential for CO{sub 2} storage because of their appropriated reservoir quality, depth and proximity to the most important stationary CO{sub 2} sources in Brazil. Here it is suggested that CO{sub 2} can be permanently stored as carbonates as CO{sub 2} reacts with rocks of the Rio Bonito Formation and forms CaCO{sub 3} at temperatures and pressures similar to those encountered for CO{sub 2} storage in geological formations. Results of this work will be useful for studies of partitioning mechanisms for C trapping in CO{sub 2} storage programs.

Ketzer, J.M. [Brazilian Carbon Storage Research Center, Pontifical Catholic University, Av. Ipiranga 6681, Building 96J, Porto Alegre (Brazil); Iglesias, R., E-mail: rsiglesias@gmail.com [Brazilian Carbon Storage Research Center, Pontifical Catholic University, Av. Ipiranga 6681, Building 96J, Porto Alegre (Brazil); Einloft, S.; Dullius, J.; Ligabue, R.; Lima, V. de [Brazilian Carbon Storage Research Center, Pontifical Catholic University, Av. Ipiranga 6681, Building 96J, Porto Alegre (Brazil)

2009-05-15

274

An integrated study of the NE German Basin  

Science.gov (United States)

The NE German Basin 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 NE German Basin. 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 can be subject to further evaluation. Furthermore, it is shown that the NE German Basin is an outstanding feature quite different from classical basin types. As the Moho is flat below the basin, neither a simple-shear-, nor a pure-shear-extension model can be applied. Instead, a thick high-velocity lower crustal layer is present below the basin centre. This high-velocity lower crust is also observed in the western part of the basin and can be taken as characteristic for East Avalonia. Results of gravity modelling indicate the presence of a high-density lower crust, thus supporting the wide-angle data. Furthermore, changes in crustal structure can be derived from changes in reflectivity pattern and from the gravimetric signature along the Elbe Fault System, indicating the presence of different crustal domains north and south of the fault system. An elastic plate model, where the forces applied are the sediment load, a vertical load at the southern margin accounting for the Harz Moutains and a NNE-SSW-directed compression, indicates a buckling of the crust during Late Cretaceous to Tertiary inversion. However, the correlation between the observed crustal structure and the tectonic events that have affected the area remains a subject of discussion. A Permian thermal event affected the upper mantle and the lower crust and, therefore, may have modified the 'crustal memory' with regard to Caledonian and Variscan events. Additional tectonic events affected the area during the Mesozoic. In conclusion, it remains an open question whether the high-velocity and high density lower crustal structure represents a remnant of East Avalonia, whether it is related to the formation of the Permo-Triassic basin, or is the cumulative result of a series of events during the Palaeozoic and Mesozoic.

Bayer, U.; Scheck, M.; Rabbel, W.; Krawczyk, C. M.; Götze, H.-J.; Stiller, M.; Beilecke, Th.; Marotta, A.-M.; Barrio-Alvers, L.; Kuder, J.

1999-12-01

275

Late Paleozoic basin evolution in the Western Pyrenees  

Science.gov (United States)

Late-Variscan (Late Carboniferous-Early Triassic) evolution in the Axial Zone of the Pyrenees is characterised by continental, intra-mountainous basin formation. These basins are presently preserved in the hangingwall of the main thrusts responsible for the uplift of the Axial Zone (Gavarnie thrust in the western Pyrenees and Nogueres thrust system in the central Pyrenees). Sedimentary sequences filling the Late Variscan basins developed under a post-collisional, strike-slip regime, with thrust-top facies, and evolved toward an extensional setting during Permian times with fluvial and lacustrine facies accompanied by extensive pyroclastic deposition (Gisbert, 1984), still before the onset of widespread extensional sedimentation corresponding to the beginning (Early Triassic) of the Alpine cycle. The continental successions are preserved in basins organised along the E-W direction, parallel to the present-day outcrop of the Axial Zone of the Pyrenees, with limited extension and lengthening in the same direction. Although it is difficult to infer the actual position of the main faults limiting the Late-Variscan basins because of the Tertiary compressional deformation and basin inversion, the main faults limiting these basins are considered to have a WNW-ESE direction, with other oblique or near-perpendicular faults responsible for the occurrence of no-sedimentation areas along-strike of the Axial Zone. Between the Variscan basement (mainly consisting of Devonian limestones and Carboniferous turbiditic Culm facies) and the Alpine sedimentary cover (Early Triassic continental deposits), the Stephanian-Autunian record is a fining-upward lacustrine, 1000-1500 m thick sedimentary succession constituted by dolomitic limestones, conglomerates, sandstones and siltstones. It is organized in four depositional units: Grey Unit (Stephanian B), Intermediate Unit (Stephanian B- Autunian), Lower Red Unit (Autunian) and Upper Red Unit (late Permian). The entire succession is limited at the bottom and top by first order unconformities all along the Pyrenean chain, and second order paraconformities can be identified within the lacustrine succession. Although these units are traditionally considerated as purely sedimentary (Gisbert, 1981), metamorphic parageneses (greenschist facies) have been locally recognized in one of these basins (Aragón-Bearn basin) in the Lower Red Unit below the paraconformity that marks the beginning of the Upper Red Unit (Lago et al., 2004). This metamorphism has been interpreted as related to later intrusion of andesitic bodies, although its causes are still matter of debate. In order to better constrain the origin and features of this metamorphism, we present results of fluid inclusions micro-thermometric studies on quartz and calcite veins and mineralogical XRD analyses of the sector of the Pyrenees.

Cantarelli, V.; Casas-Sainz, A.; Corrado, S.; Gisbert-Aguilar, J.; Invernizzi, C.; Aldega, L.

2009-04-01

276

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

277

Molecular carbon isotope variations in core samples taken at the Permian-Triassic boundary layers in southern China  

Science.gov (United States)

Stable carbon isotope composition (?13C) of carbonate sediments and the molecular (biomarker) characteristics of a continuous Permian-Triassic (PT) layer in southern China were studied to obtain geochemical signals of global change at the Permian-Triassic boundary (PTB). Carbonate carbon isotope values shifted toward positive before the end of the Permian period and then shifted negative above the PTB into the Triassic period. Molecular carbon isotope values of biomarkers followed the same trend at and below the PTB and remained negative in the Triassic layer. These biomarkers were acyclic isoprenoids, ranging from C15 to C40, steranes (C27 dominates) and terpenoids that were all significantly more abundant in samples from the Permian layer than those from the Triassic layer. The Triassic layer was distinguished by the dominance of higher molecular weight (waxy) n-alkanes. Stable carbon isotope values of individual components, including n-alkanes and acyclic isoprenoids such as phytane, isop-C25, and squalane, are depleted in ?13C by up to 8-10‰ in the Triassic samples as compared to the Permian. Measured molecular and isotopic variations of organic matter in the PT layers support the generally accepted view of Permian oceanic stagnation followed by a massive upwelling of toxic deep waters at the PTB. A series of large-scale (global) outgassing events may be associated with the carbon isotope shift we measured. This is also consistent with the lithological evidence we observed of white thin-clay layers in this region. Our findings, in context with a generally accepted stagnant Permian ocean, followed by massive upwelling of toxic deep waters might be the major causes of the largest global mass extinction event that occurred at the Permian-Triassic boundary.

Wang, Ruiliang; Zhang, Shuichang; Brassell, Simon; Wang, Jiaxue; Lu, Zhengyuan; Ming, Qingzhong; Wang, Xiaomei; Bian, Lizeng

2012-07-01

278

Uranium mineralization in the Permian volcanic rocks at Kravany, Kozie Chrbty Mts., Western Carpathians, Slovak Republic: Preliminary results  

International Nuclear Information System (INIS)

Rock debris with uranium mineralization were found at the Kravany village. Ore mineralization occurs in quartz-calcite-dolomite gangue located in the altered, fine-grained Permian diorite porphyrite. Mineralization is represented by uraninite, Pb phase (?) and arsenic-rich pyrite, and is accompanied by arsenic-free pyrite, chalcopyrite, tetrahedrite, sphalerite and galena. The origin of the mineralization can be probably explained by infiltration of uranium-bearing solutions from the sedimentary Kravany Member of Permian age to volcanic rocks. (author)

279

Origin of Permian gabbroic intrusions in the southern margin of the Altai Orogenic belt: A possible link to the Permian Tarim mantle plume?  

Science.gov (United States)

Zircon U-Pb dating and Hf isotopic compositions, whole-rock and mineral geochemistry, as well as field and petrographic observations, are reported for the Permian gabbroic intrusions in the southern margin of the Altai orogenic belt. Similar zircon ages (~ 280 Ma) of these intrusions to that of the Permian Tarim mantle plume suggest a possible link to the Tarim plume. Olivine grains from the intrusions have Fo contents ranging from 69 to 81 and NiO from 0.05 to 0.21 wt.%, indicating the crystallization from evolved mafic magmas. Clinopyroxene grains from the intrusions have 0.3 to 1.5 wt.% TiO2 and display a rift- to arc-like affinity. The intrusions are tholeiitic and have slightly LREE-depleted to LREE-enriched chondrite-normalized rare earth element (REE) patterns. Zircons from the intrusions have ?Hf(t) values higher than + 8.0, whereas the whole-rock ?Nd(t) values range from + 2.7 to + 7.0. Rocks from the intrusions have Nb/La of 0.2 to 0.8, consistent with the derivation from a depleted sub-lithospheric mantle with variable degrees of crustal contamination. The presence of primary hornblende and/or biotite in the rocks indicates metasomatism by slab-derived fluids/melts in the mantle source. We propose that upwelling of asthenospheric mantle in the Permian Tarim mantle plume along the Irtish suture zone, resulted in partial melting of the sub-continental lithospheric mantle. Based on a comparison between the Ni-Cu sulfide-bearing Kalatongke complex and un-mineralized intrusions, we suggest that Ni-Cu sulfide mineralized intrusions in the Altai orogenic belt are characterized by the enrichments of LREEs and LILEs and by the presence of primary water-bearing minerals.

Zhang, Chuan-Lin; Zou, Hai-Bo; Yao, Chun-Yan; Dong, Yong-Guan

2014-09-01

280

Detrital zircon and sandstone provenance analysis from Permian and Lower Cretaceous sedimentary units to constrain total and incremental left-lateral offset along the East Gobi Fault Zone, southeastern Mongolia  

Science.gov (United States)

This study presents initial U-Pb detrital zircon geochronology results coupled with sandstone provenance point-counting to constrain sedimentary basin evolution along the East Gobi Fault Zone (EGFZ), southeastern Mongolia. These results fingerprint potential piercing points in sedimentary units argued here to have once been part of the same depositional basins, now offset by the strike-slip fault zone. Detrital zircon samples were collected and analyzed using LA-ICPMS from two sets of proposed offset-basin systems: Permian fluvial and marine units at Bulgan Uul and Nomgon, and Cretaceous fluvial units at Tavan Har and Ulgay Khid (11 sandstone samples total). The age probability plots for Bulgan Uul and Nomgon, as well as Tavan Har and Ulgay Khid, show very convincing correlations with significant implications. The Late Permian Lugyn Gol units at Nomgon are currently ~270 km northeast of those Late Permian Onch Uul samples at Bulgan Uul, and provide similar age probability plots, with most significant peaks at ~280 Ma and ~440 Ma, for zircons of igneous origins based on U/Th ratios. Lower Cretaceous strata from Tavan Har and Ulgay Khid are currently located ~90 km left-laterally off-set from each other, and also show strong correlation with significant age probability peaks centered at ~280 Ma and ~120 Ma, also with igneous origins. As the detrital zircon data are not intended to stand alone, 23 samples including all the zircon samples were point-counted for establishing provenance. QFL ternary plots indicate semi-mature, recycled orogen and arc sources for samples collected at Bulgan Uul, Nomgon, and Ulgay Khid. Tavan Har, however, primarily plotted in the dissected arc field. The results presented here argue for the following three main findings: First, detrital zircon analysis shows a clear connection of Bulgan Uul and Nomgon, as well as Ulgay Khid and Tavan Har. These cross-fault stratigraphic connections are further supported in most cases by the provenance point-counting results as well. Second, the ability to connect these cross-fault sedimentary units establishes piercing points thereby providing a means to calculated total and incremental offset along the EGFZ. Roughly 270 km of total sinistral offset has occurred along the EGFZ since the Late Permian, approximately 90 km of which has occurred since the mid Cretaceous. Therefore ~180 km of left-lateral offset along the EGFZ has occurred in the Triassic and Jurassic periods of deformation previously identified by other investigators. Paleo-reconstructions using these results and proprietary total magnetic survey data (TMI), suggest Bulgan Uul would have been located northwest of Nomgon prior to the onset of initial deformation. Finally, the presence of 910 Ma zircons in the detrital record for samples collected at Bulgan Uul and rarely at Nomgon supports the indenter model proposed by Johnson et al. (2008) for closure of the Paleoasian Ocean in the Late Permian, with the North China block being emplaced by this time.

Heumann, M.; Johnson, C.; Webb, L.; Taylor, J.

2008-12-01

 
 
 
 
281

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.)

282

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

283

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

Directory of Open Access Journals (Sweden)

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

Aymon Baud

2005-10-01

284

Subsidence hazards caused by the dissolution of Permian gypsum in England : geology, investigation and remediation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

About every three years natural catastrophic subsidence, caused by gypsum dissolution, occurs in the vicinity of Ripon, North Yorkshire, England. Holes up to 35 m across and 20 m deep have appeared without warning. In the past 150 years, 30 major collapses have occurred, and in the last ten years the resulting damage to property is estimated at about £1000000. Subsidence, associated with the collapse of caves resulting from gypsum dissolution in the Permian rocks of eastern England, occurs i...

Cooper, A. H.

1998-01-01

285

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

286

Abrupt environmental and climatic change during the deposition of the Early Permian Haushi limestone, Oman  

Digital Repository Infrastructure Vision for European Research (DRIVER)

During the late Sakmarian (Early Permian), the Haushi limestone was deposited in a shallow embayment of the Neotethys Ocean covering what is now north Oman and parts of southeast Saudi Arabia. The sea persisted through the late Sakmarian, but by the time of the deposition of the ?Artinskian Middle Gharif Member, limestone deposition had ceased and generally arid fluvial and minor lacustrine palaeonvironments in a low accommodation space setting had become established. Analysis of three subsur...

Stephenson, Michael; Angiolini, Lucia; Leng, Melanie; Brewer, T. S.; Berra, F.; Jadoul, F.; Gambacorta, G.; Verna, V.; Al Beloushi, B.

2008-01-01

287

Diagenetic and Detrial Origin of Moretane Anomalies through the Permian-Triassic Boundary  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Many biogeochemical anomalies coincide with the Late Permian Extinction (LPE; 252.28 Ma). Several mechanisms have been proposed to explain the moretane/hopane anomaly that has been identified in samples from Meishan GSSP section in southeastern China. Here, we report homohopane, 2?- and 3?-methylhomohopane and lithological data for a drill core from the Meishan section in southeastern China. Three intervals of elevated C30 moretane/hopane ratios are recorded in the Lungtan, Yinkeng and Helo...

French, Katherine L.; Tosca, Nicholas J.; Cao, Changqun; Summons, Roger Everett

2011-01-01

288

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2000-08-01

289

Palinología de la Formación Tasa Cuna (Pérmico Inferior), Córdoba, Argentina: sistemática y consideraciones bioestratigráficas / Palynology of the Tasa Cuna formation (Lower Permian), Córdoba, Argentina: systematics and biostratigraphic considerations  

Scientific Electronic Library Online (English)

Full Text Available SciELO Argentina | Language: Spanish Abstract in spanish Se describe una asociación microflorística proveniente de la Formación Tasa Cuna, noroeste de la provincia de Córdoba, dentro del ámbito de la cuenca Paganzo. La misma es referida a la Biozona de Intervalo Pakhapites fusus-Vittatina subsaccata del Pérmico Inferior y se correlaciona con la Biozona Cr [...] istatisporitesde la cuenca Chacoparaná. La presencia de Striatopodocarpites communis (Wilson) Hart, Vittatina sp cf. V. fasciolata (Balme y Hennelly) Bharadwaj, V. subsaccata Samoilovich emend. Jansonius, Vittatina sp. cf. V. vittifera (Luber) Samoilovich, Hamiapollenites sp. cf. H. bullaeformis (Samoilovich) Jansonius, H. fusiformis Marques-Toigo emend. Archangelsky y Gamerro, Pakhapites fusus (Bose y Kar) Menéndez, Lunatisporites sp. cf. L. variesectus Archangelsky y Gamerro y Scheuringipollenites medius (Burjack) Dias-Fabrício, apoya la edad de la asociación. Se indentifica por primera vez para la Argentina Hamiapollenitessp. cf. H. bullaeformis, Striatopodocarpites sp. cf. S. crassus Singh, S. sp. cf. S. rarus (Bharadwaj y Salujha) Balme, S. communis (Wilson) Hart y Protohaploxypinus hagii Foster. La asociación representaría a una comunidad vegetal de ambientes lénticos caracterizada por la abundancia de Licofitas, a su vez, influenciada por el aporte de comunidades gimnospérmicas (en particular, Coniferales y Cordaitales), quienes a pesar de tener requerimientos meso-xerofíticos, se habrían desarrollado cerca del cuerpo de agua donde se depositó la asociación. Abstract in english A palynological association belonging to the Tasa Cuna Formation, northwest of Córdoba Province, Paganzo Basin, is described. This assemblage is referred to the Pakhapites fusus-Vittatina subsaccata Biozone, Early Permian, and it is correlated with the Cristatisporites Biozone, Chacoparaná Basin. Th [...] e ocurrences of Striatopodocarpites communis (Wilson) Hart, Vittatina sp. cf. V. fasciolata (Balme and Hennelly) Bharadwaj, V. subsaccata Samoilovich emend. Jansonius, Vittatina sp. cf. V. vittifera (Luber) Samoilovich, Hamiapollenites sp. cf. H. bullaeformis (Samoilovich) Jansonius, H. fusiformis Marques-Toigo emend. Archangelsky and Gamerro, Pakhapites fusus (Bose and Kar) Menéndez, Lunatisporites sp. cf. L. variesectus Archangelsky and Gamerro, and Scheuringipollenites medius (Burjack) Dias-Fabrício, support the inclusion of this palynological association in the Early Permian. Some species such as Hamiapollenites sp. cf. H. bullaeformis (Samoilovich) Jansonius, Striatopodocarpites sp. cf. S. crassus Singh, S. sp. cf. S. rarus (Bharadwaj and Salujha) Balme, S. communis (Wilson) Hart, and Protohaploxypinus hagii Foster, are identified in Argentina for the first time. This assemblage would represent a community related to lacustrine paleoenvironment characterized by abundant Lycophytes and influenced by a gymnospermic community (particularly Coniferales and Cordaitales) that, in spite of having meso-xerophytic requirements, would have been developed close to a fresh water body, where the assemblage was deposited.

María Lucía, Balarino; Pedro Raúl, Gutiérrez.

2006-06-01

290

Palinología de la Formación Tasa Cuna (Pérmico Inferior), Córdoba, Argentina: sistemática y consideraciones bioestratigráficas / Palynology of the Tasa Cuna formation (Lower Permian), Córdoba, Argentina: systematics and biostratigraphic considerations  

Scientific Electronic Library Online (English)

Full Text Available SciELO Argentina | Language: Spanish Abstract in spanish Se describe una asociación microflorística proveniente de la Formación Tasa Cuna, noroeste de la provincia de Córdoba, dentro del ámbito de la cuenca Paganzo. La misma es referida a la Biozona de Intervalo Pakhapites fusus-Vittatina subsaccata del Pérmico Inferior y se correlaciona con la Biozona Cr [...] istatisporitesde la cuenca Chacoparaná. La presencia de Striatopodocarpites communis (Wilson) Hart, Vittatina sp cf. V. fasciolata (Balme y Hennelly) Bharadwaj, V. subsaccata Samoilovich emend. Jansonius, Vittatina sp. cf. V. vittifera (Luber) Samoilovich, Hamiapollenites sp. cf. H. bullaeformis (Samoilovich) Jansonius, H. fusiformis Marques-Toigo emend. Archangelsky y Gamerro, Pakhapites fusus (Bose y Kar) Menéndez, Lunatisporites sp. cf. L. variesectus Archangelsky y Gamerro y Scheuringipollenites medius (Burjack) Dias-Fabrício, apoya la edad de la asociación. Se indentifica por primera vez para la Argentina Hamiapollenitessp. cf. H. bullaeformis, Striatopodocarpites sp. cf. S. crassus Singh, S. sp. cf. S. rarus (Bharadwaj y Salujha) Balme, S. communis (Wilson) Hart y Protohaploxypinus hagii Foster. La asociación representaría a una comunidad vegetal de ambientes lénticos caracterizada por la abundancia de Licofitas, a su vez, influenciada por el aporte de comunidades gimnospérmicas (en particular, Coniferales y Cordaitales), quienes a pesar de tener requerimientos meso-xerofíticos, se habrían desarrollado cerca del cuerpo de agua donde se depositó la asociación. Abstract in english A palynological association belonging to the Tasa Cuna Formation, northwest of Córdoba Province, Paganzo Basin, is described. This assemblage is referred to the Pakhapites fusus-Vittatina subsaccata Biozone, Early Permian, and it is correlated with the Cristatisporites Biozone, Chacoparaná Basin. Th [...] e ocurrences of Striatopodocarpites communis (Wilson) Hart, Vittatina sp. cf. V. fasciolata (Balme and Hennelly) Bharadwaj, V. subsaccata Samoilovich emend. Jansonius, Vittatina sp. cf. V. vittifera (Luber) Samoilovich, Hamiapollenites sp. cf. H. bullaeformis (Samoilovich) Jansonius, H. fusiformis Marques-Toigo emend. Archangelsky and Gamerro, Pakhapites fusus (Bose and Kar) Menéndez, Lunatisporites sp. cf. L. variesectus Archangelsky and Gamerro, and Scheuringipollenites medius (Burjack) Dias-Fabrício, support the inclusion of this palynological association in the Early Permian. Some species such as Hamiapollenites sp. cf. H. bullaeformis (Samoilovich) Jansonius, Striatopodocarpites sp. cf. S. crassus Singh, S. sp. cf. S. rarus (Bharadwaj and Salujha) Balme, S. communis (Wilson) Hart, and Protohaploxypinus hagii Foster, are identified in Argentina for the first time. This assemblage would represent a community related to lacustrine paleoenvironment characterized by abundant Lycophytes and influenced by a gymnospermic community (particularly Coniferales and Cordaitales) that, in spite of having meso-xerophytic requirements, would have been developed close to a fresh water body, where the assemblage was deposited.

María Lucía, Balarino; Pedro Raúl, Gutiérrez.

291

Modern Pearl River Delta and Permian Huainan coalfield, China: A comparative sedimentary facies study  

Science.gov (United States)

Sedimentary facies types of the Pleistocene deposits of the Modern Pearl River Delta in Guangdong Province, China and Permian Member D deposits in Huainan coalfield in Anhui Province are exemplified by depositional facies of anastomosing fluvial systems. In both study areas, sand/sandstone and mud/mudstone-dominated facies types formed in diverging and converging, coeval fluvial channels laterally juxtaposed with floodplains containing ponds, lakes, and topogenous mires. The mires accumulated thin to thick peat/coal deposits that vary in vertical and lateral distribution between the two study areas. This difference is probably due to attendant sedimentary processes that affected the floodplain environments. The ancestral floodplains of the Modern Pearl River Delta were reworked by combined fluvial and tidal and estuarine processes. In contrast, the floodplains of the Permian Member D were mainly influenced by freshwater fluvial processes. In addition, the thick, laterally extensive coal zones of the Permian Member D may have formed in topogenous mires that developed on abandoned courses of anastomosing fluvial systems. This is typified by Seam 13-1, which is a blanket-like body that thickens to as much as 8 in but also splits into thinner beds. This seam overlies deposits of diverging and converging, coeval fluvial channels of the Sandstone D, and associated overbank-floodplain deposits. The limited areal extent of lenticular Pleistocene peat deposits of the Modern Pearl River Delta is due to their primary accumulation in topogenous mires in the central floodplains that were restricted by contemporaneous anastomosing channels.

Suping, P.; Flores, R. M.

1996-01-01

292

Mid-Permian Phosphoria Sea in Nevada and the Upwelling Model  

Science.gov (United States)

The Phosphoria Sea extended at least 500 km westward and at least 700 km southwestward from its core area centered in southeastern Idaho. Throughout that extent it displayed many characteristic features of the core: the same fauna, the same unique sedimentary assemblage including phosphate in mostly pelletal form, chert composed mainly of sponge spicules, and an association with dolomite. Phosphoria-age sediments in Nevada display ample evidence of deposition in shallow water. The chief difference between the sediments in Nevada and those of the core area is the greater admixture of sandstone and conglomerate in Nevada. Evidence of the western margin of the Phosphoria Sea where the water deepened and began to lose its essential characteristics is located in the uppermost part of the Upper Devonian to Permian Havallah sequence, which has been displaced tectonically eastward an unknown distance. The relatively deep water in which the mid-Permian part of the Havallah was deposited was a sea of probably restricted east-west width and was floored by a very thick sequence of mainly terrigenous sedimentary rocks. The phosphate content of mid-Permian strata in western exposures tends to be relatively low as a percentage, but the thickness of those strata tends to be high. The core area in and near southeastern Idaho where the concentration of phosphate is highest was separated from any possible site of upwelling oceanic waters by a great expanse of shallow sea.

Ketner, Keith B.

2009-01-01

293

Discussion of gas enrichment mechanism and natural gas origin in marine sedimentary basin, China  

Energy Technology Data Exchange (ETDEWEB)

There are abundant natural gas resources in Chinese marine sedimentary basin. The exploration hot shots of natural gas are the Palaeozoic marine strata here in recent years, and several large scale gas fields have been discovered. Chinese Palaeozoic high-post matured and coal measure hydrocarbon source rocks are mainly prone to gas generation in the present. This research considered that gas source rocks and TSR are the key cause of gas enrichment of marine strata. High-quality argillaceous and coal measure hydrocarbon rocks are distributed widely in the Palaeozoic marine strata, which have been in highly matured phase in the present. The argillaceous source rock generally contains various sulfates that could accelerate crude oil cracking to gas for TSR occurrence, and coal measure source rock mainly generates gas, so Chinese marine basin gives priority to accumulating gas. Marine strata have not founded oil reservoirs in the Sichuan Basin and Ordos Basin, and they consist mainly of dry gas. Marine natural gases are the mixed gases of oil cracking gas and coal-formed gas in a general way, oil cracking gases contain usually some H{sub 2}S and CO{sub 2}. Hydrocarbon carbon isotopes are very complicated, and methane and ethane isotopic values bear apparent reversal caused by thermal evolution and mixing among different genetic types of natural gas. Coal-formed gases are the main component of Chinese marine natural gas. The Upper Permian of the Sichuan Basin and the Carboniferous-Permian of the Ordos Basin coal measure hydrocarbon source rock present large hydrocarbon generation potential, which are the prospecting highlight of marine natural gas hereafter. Oil cracking gas exploration will be paid much attention to in the Tarim Basin because of the lack of coal measure hydrocarbon source rock.

Zhu, G.Y.; Zhao, W.Z.; Zhang, S.C.; Liang, Y.B.; Wang, Z.J.

2007-11-15

294

Late Permian Tsunamites in Guryul Ravine (Kashmir, India) - revisited and rejected  

Science.gov (United States)

Recent claims for tsunami-related event beds induced by the Siberian Trap basalts in this section (Brookfield et al., 2013) have to be questioned. Identical storm generated carbonate beds occur not only during a short interval close to the Permian-Triassic (P-T) boundary but through a major part of the late Permian (Changhsingian) succession there - as low as 26 m below the so-called tsunami beds. Moreover, during our recent study in a closely neighbouring place called Mandakpal (less than 10 km to the southeast), no signs of tsunamites have been detected in time-correlative finegrained sediments. Based on sedimentary and trace fossil evidence we interpret the late Permian of Guryul as relatively shallow, neritic and delta-influenced. The so-called tsunamites are shelly-enriched discontinuous carbonate lenses fed downslope through local channels. Judging from the distinct facies change from the storm related "tsunamites" to thinly bedded mud turbidites above, the sudden deepening may be explained by local and still rift-related tectonics along the NIM (North-Indian Gondwana Margin) which led to episodic seismic induced sediment redeposition in the area of Guryul. Synsedimentary tectonic activity with tilting and eventual Horst and Graben structure building along the large NIM is indicated by margin inversion during the P-T boundary interval leading to sedimentary breaks and 20 times thinner, condensed limestone deposits far offshore from Guryul in Spiti (Krystyn et al., 2004) and Tibet (Orchard et al., 1994). Thus, local seismic activity seems to be a far more logic explanation of the Guryul "tsunamites" than the eruption of the Siberian Traps more than 6000 km away. References Brookfield, M. E., Algeo, T. J., Hannigan, R., Williams, J and Bhat, G. M., 2013: Shaken and Stirred: Seismites and Tsunamites at the Permian-Triassic boundary, Guryul Ravine, Kashmir, India. Palaios, v. 28, 568-582. Krystyn, L., Balini, M. and Nicora, A., 2004: Lower and Middle Triassic stage boundaries in Spiti. Albertiana, v. 30, 40-53. Orchard, M.J., Nassichuk, W.W., Rui Lin, 1994: Conodonts from the lower Griesbachian Otoceras latilobatum Bed of Selong, Tibet and the position of the Permian-Triassic boundary. In: Pangea: Global Environments and Resources, Memoirs of the Canadian Society of Petroleum Geologists, vol. 17, 823-843.

Krystyn, Leopold; Horacek, Micha; Brandner, Rainer; Parcha, Suraj

2014-05-01

295

Integrated Vitrinite Reflectance and Apatite Fission Track Thermocronology of the Lower Karoo rocks in the Moatize Basin, Tete Province, Mozambique.  

Science.gov (United States)

The Karoo in Mozambique is represented by Late Carboniferous to Late Triassic sediments that were deposited in rift basins that fringe or developed between Proterozoic cratons. In Tete Province, central-west Mozambique, the Karoo is well represented along the Zambezi river valley forming several intra-cratonic basins separated by horsts consisting of igneous and high grade metamorphic Proterozoic rocks. One of the main horst blocks is located between the Cahora Bassa region and Tete city, separating the Middle Zambezi Basin and the Lower Zambezi Basin. The area of study is located in the Moatize Basin, one of many small basins that form the Lower Zambezi Basin. The stratigraphy of this basin consists of several sedimentary formations that record changes in depositional environment and palaeoclimate from glacial (Vúzi Formation - Lower Permian) at the base, through wet to temperate in the middle (Moatize Formation - Lower Permian), to warm arid at the top of the succession (Matinde and Cádzi formations - Middle to Upper Permian). The Upper Karoo volcanics of Early Jurassic age do not crop out in the Moatize Basin. One of the most remarkable characteristics of the Moatize Basin is the richness of coal deposits present in the Lower Permian Moatize Formation. Two coal exploration boreholes (DW123 - T.D. 489 m and DW132 - T.D. 516 m) drilled in the Moatize Basin were studied by means of vitrinite reflectance (VR) and apatite fission track analysis (AFTA), in order to assess their burial and uplift histories. The two boreholes intersected only Moatize Formation lithologies. VR increases in the two borehole sections from ca. 1.30-1.32 % Ro at the top to ca. 1.52-1.69 % Ro at the bottom, indicating medium to low volatile coal rank. Modelled VR data from the two boreholes indicate palaeogeothermal gradients between 40 and 56ºC/km, possible related to basin forming processes. Fission track ages increase from 84 Ma and 102 Ma at the bottom to 138 Ma and 146 Ma at the top of the DW132 and DW123 wells respectively. The Mean Track Length is approximately 11.7±0.2 ?m for the four samples studied. Inverse modelling of both VR and fission track data have been undertaken with QTQt software. The results are consistent for the two boreholes. Thermal histories indicate that samples have been heated to a maximum temperature of 150 to 180 °C following deposition. Maximum temperature was reached at 260 Ma., then a first phase of cooling occurred between 255 and 230 Ma, related to post Lower Karoo exhumation. The sections subsequently cooled very slowly until Neogene time. At 7 Ma, a second, fast cooling episode reduced rock temperatures from 50 - 60 °C to present day temperature. This second cooling episode is possibly related to exhumation caused by the uplift and erosion of the East-African rift shoulders. The thermal reconstruction indicates that the present coal rank was attained shortly after deposition. Following this burial under a thick sedimentary sequence of approximately 4 km, two main pulse of exhumation affected the Moatize Basin during the Triassic and Pliocene, eroding ca. 2.5 km of Upper Permian strata in the first and 1.5 km in the latter.

Fernandes, Paulo; Cogné, Nathan; Rodrigues, Bruno; Jorge, Raul; Marques, João

2014-05-01

296

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

297

Paleomagnetism and Thermal History of the Permian Succession of the Velebit Mts (Dinarides, Croatia)  

Science.gov (United States)

The studied area of Velebit Mts, a part of the Adria Microplate, belonged to a NE margin of Gondwana during the Carboniferous and Permian. While Permian is characterised by clastics, post-Permian sedimentation is dominated by a thick sequence of carbonate rocks. Today, the entire sequence, representing a stratigraphic range from Carboniferous to Recent, is in places more than 10,000 m thick. The mid-Permian deposits of the core part of the Velebit Mt. at Kosna and Crne Grede localities were investigated using paleomagnetic and rock magnetic measurements, supported by XRD, AFT and K-Ar studies of the clastic part of the profile (Carboniferous to Triassic). Hysteresis studies revealed that magnetic susceptibility of reddish siltstones/sandstones as well as underlying conglomerates is mostly carried by the paramagnetic matrix with a significant but varying contribution of hematite and some SP/SD magnetite. AMS fabric with low anisotropy ratio (1-3%) is strongly oblate at Kosna and weakly prolate at Crne Grede, reflecting differences in the contribution of magnetic phases. Thermal enhancement of AMS results in substantial increase of susceptibility, anisotropy ratio and more oblate fabric due to growth of SP magnetite fraction,.Enhanced AMS fabric tends to mimic tectonic fabric supporting that SP/SD magnetite is younger syntectonic phase more prone to record younger remagnetization. The paleotemperatures have been estimated by clay minerals analyses of the Carboniferous, Permian and Triassic shales. K-Ar and apatite fission track analyses (AFT) provided time constraints for the maximum paleotemperature and the uplift event, respectively. The paleotemperature estimates gave a range from ca. 140 to more than 200°C. Generally, the highest paleotemperatures are recorded within the Carboniferous rocks. K-Ar measurements of multiple fractions of illite-smectite separated from Triassic bentonites gave a consistent range of the Late Cretaceous ages of the maximum paleotemperatures between 100 and 60 Ma. AFT performed on sediments of Carboniferous to Triassic age indicate complete track resetting. The preliminary AFT dating results indicates two cooling episodes around 55 and 28 Ma. Track length distribution analyses conducted on older age population suggest slow to moderate cooling rates. A significant remagnetization of the Permian rocks (proved by results of conglomerate test), probably caused by combination of elevated temperature and fluids migration, may be assigned to a burial-related processes that affected the rocks before the final uplift of the Dinarides. Characteristic remanent magnetization is apparently similar to the Permian direction for Gondwana (shallow inclination with NNW declination), expected for Velebit Mt. coordinates. Paradoxically, this orientation is observed within the almost vertically dipping beds, i.e. before a correction for the tilt. We explain this coincidence assuming syn-folding, Cretaceous-Paleogene remagnetization of the rocks at their subhorizontal position (ca. 30°S) followed by tilting, understood as a rotation of the beds along the horizontal, E-W trending axis to almost vertical, present-day position. A final geometry of the rocks under study was attained probably at the wane of the main uplift phase in Oligocene/Early Miocene. Polish Ministry of Science and Higher Education, grant no. N N307 475238.

Lewandowski, M.; Werner, T.; Vlahovic, I.; Srodon, J.; Anczkiewicz, A.; Velic, I.; Sidorczuk, M.

2012-12-01

298

Advanced Oil Recovery Technologies for Improved Recovery From Slope Basin Clastic reservoirs, Nash Draw Brushy Canyon Pool, Eddy County, New Mexico  

Energy Technology Data Exchange (ETDEWEB)

The overall goal of this project is to demonstrate that an advanced development drilling and pressure maintenance program based on advanced reservoir management methods can significantly improve oil recovery. The plan included developing a control area using standard reservoir management techniques and comparing its performance to an area developed using advanced methods. A key goal is to transfer advanced methodologies to oil and gas producers in the Permian Basin and elsewhere, and throughout the US oil and gas industry.

Mark B. Murphy

1998-04-30

299

Advanced Oil Recovery Technologies for Improved Recovery From Slope Basin Clastic Reservoirs, Nash Draw Brushy Canyon Pool, Eddy County, New Mexico  

Energy Technology Data Exchange (ETDEWEB)

The overall goal of this project is to demonstrate that an advanced development drilling and pressure maintenance program based on advanced reservoir management methods can significantly improve oil recovery. The plan included developing a control area using standard reservoir management techniques and comparing its performance to an area developed using advanced methods. A key goal is to transfer advanced methodologies to oil and gas producers in the Permian Basin and elsewhere, and throughout the US oil and gas industry.

Mark B. Murphy

1997-07-30

300

Advanced Oil Recovery Technologies for Improved Recovery From Slope Basin Clastic Reservoirs, Nash Draw Brushy Canyon Pool, Eddy County, New Mexico  

Energy Technology Data Exchange (ETDEWEB)

The overall goal of this project is to demonstrate that an advanced development drilling and pressure maintenance program based on advanced reservoir management methods can significantly improve oil recovery. The plan included developing a control area using standard reservoir management techniques and comparing its performance to an area developed using advanced methods. A key goal is to transfer advanced methodologies to oil and gas producers in the Permian Basin and elsewhere, and throughout the US oil and gas industry.

Mark B. Murphy

1997-04-30

 
 
 
 
301

Paleogeothermal record of the Emeishan mantle plume: evidences from borehole Ro data in the Sichuan basin, SW China  

Science.gov (United States)

The Emeishan basalt province located in the southwest of China is widely accepted to be a result of the eruption of a mantle plume at the time of middle-late Permian. If it was a mantle plume, the ambient sedimentary rocks must be heated up during the development of the mantle plume and this thermal effect must be recorded by some geothermometers in the country rocks. The vitrinite reflectance (Ro) data as a maximum paleotemperature recorder from boreholes in Sichuan basin was employed to expose the thermal regime related to the proposed Emeishan mantle plume. The Ro profiles from boreholes which drilled close to the Emeishan basalts shows a ';dog-leg' (break) style at the unconformity between the middle and the upper Permian, and the Ro profiles in the lower subsection (pre-middle Permian) shows a significantly higher slopes (gradients) than those in the upper subsection. In contrast, those Ro profiles from boreholes far away from the center of the basalt province have no break at the uncomformity. Based on the chemical kinetic model of Ro, the paleo-temperature gradients for the upper and the lower subsections in different boreholes, as well as the erosion at the unconformity between the middle and the upper Permian, were reconstructed to reveal the variations of the temperature gradients and erosion thickness with geological time and space. Both the thermal regime and the erosion thickness together with their spatial variation (structure) provide strong geothermal evidence for the existence of the Emeishan mantle plume in the middle-late Permian.

Hu, S.

2013-12-01

302

The Role of Salt During Basin Extension and Inversion Inferred From 3d Backstripping  

Science.gov (United States)

We use a 3D backstripping approach considering salt flow as a consequence of spa- tially changing overburden load distribution, isostatic rebound and sedimentary com- paction for each backstripping step to reconstruct the salt-related deformation in the Northeast German Basin during Late Triassic-Jurassic extension and during Late Cretaceous-Early Cenozoic inversion. The Northeast German basin contains up to 8000 m of Permian to Cenozoic sediments including a thick layer of Permian Zech- stein salt. The basin was affected by extension during the Late Triassic-Jurassic and by inversion during Late Cretaceous-Early Cenozoic. This deformation is thin-skinned in the basinal part but is thick-skinned at the basin margins. While the salt basement re- mained stable, the basin margins suffered strong deformation. As a main question we address the role of salt during the thin-skinned extension and inversion of the basin. In our modeling approach, we assume that the salt behaves like a viscous fluid on the geological time-scale, that salt and overburden are in hydrostatical near-equilibrium at all times and that the volume of salt is constant. Because the basement of the salt is not deformed due to decoupling by the salt layer in the basin area, we consider the base of the salt as a reference surface, where the load pressure must be equilibrated. Our results indicate, that major salt movements took place during late Triassic to Jurassic E-W directed extension and during Late Cretaceous-Early Cenozoic NNE-SSW di- rected compression. The Late Triassic to Jurassic extension lead to the formation of the Rheinsberg Trough but did not deform the salt basement. In conclusion, the effec- tive stress did not exceed the yield strength of the basement, but was high enough to provoke deformation of the viscous salt layer and its cover. There, the salt movement may have balanced the major part of extension. During the Late Cretaceous-Early Cenozoic phase of inversion strong deformation took place along the southern basin margin leading to a present-day vertical basement offset of up to 5 km. This indicates causal tectonic forces of a considerable magnitude. We show, that horizontal strain propagation in the viscous salt layer from the southern basin margin into the basin can explain the intensive thin-skinned compressive deformation of the salt cover in the basin area.

Scheck, Magdalena; Lewerenz, Björn

303

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

304

The Timan-Pechora Basin province of northwest Arctic Russia; Domanik, Paleozoic total petroleum system  

Science.gov (United States)

The Domanik-Paleozoic oil-prone total petroleum system covers most of the Timan-Pechora Basin Province of northwestern Arctic Russia. It contains nearly 20 BBOE ultimate recoverable reserves (66% oil). West of the province is the early Precambrian Eastern European craton margin. The province itself was the site of periodic Paleozoic tectonic events, culminating with the Hercynian Uralian orogeny along its eastern border. The stratigraphic record is dominated by Paleozoic platform and shelf-edge carbonates succeeded by Upper Permian to Triassic molasse siliciclastics that are locally present in depressions. Upper Devonian (Frasnian), deep marine shale and limestone source rocks ? with typically 5 wt % total organic carbon ? by middle Mesozoic time had generated hydrocarbons that migrated into reservoirs ranging in age from Ordovician to Triassic but most focused in Devonian and Permian rocks. Carboniferous structural inversions of old aulacogen borders, and Hercynian (Permian) to Early Cimmerian (Late Triassic to Early Jurassic) orogenic compression not only impacted depositional patterns, but also created and subsequently modified numerous structural traps within the province.

Lindquist, Sandra J.

1999-01-01

305

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.

306

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

307

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

308

Geochronological data from the Faxinal coal succession, southern Parana Basin, Brazil: A preliminary approach combining radiometric U-Pb dating and palynostratigraphy  

Energy Technology Data Exchange (ETDEWEB)

A radiometric zircon age of 285.4 {+-} 8.6 Ma (IDTIMS U-Pb) is reported from a tonstein layer interbedded with coal seams in the Faxinal coalfield, Rio Grande do Sul, Brazil. Calibration of palynostratigraphic data with the absolute age shows that the coal depositional interval in the southern Parana Basin is constrained to the Sakmarian. Consequently, the basal Gondwana sequence in the southern part of the basin should lie at the Carboniferous-Permian boundary, not within the Sakmarian as previously considered. The new results are significant for correlations between the Parana Basin and the Argentinian Paganzo Basin (302 {+-} 6 Ma and 288 {+-} 7 Ma) and with the Karoo Basin, specifically with the top of the Dwyka Tillite (302 {+-} 3 Ma and 299.2 {+-} 3.2 Ma) and the lowermost Ecca Group (288 {+-} 3 Ma and 289.6 {+-} 3.8 Ma). The evidence signifies widespread latest Carboniferous volcanic activity in western Gondwana.

Guerra-Sommer, M.; Cazzulo-Klepzig, M.; Menegat, R.; Formoso, M.L.L.; Basei, M.A.; Barboza, E.; Simas, M.W. [Universidade Federal do Rio Grande do Sul, Porto Alegre (Brazil)

2008-03-15

309

Isotopic evidence for an anomalously low oceanic sulfate concentration following end-Permian mass extinction  

Science.gov (United States)

The cataclysmic end-Permian mass extinction was immediately followed by a global expansion of microbial ecosystems, as demonstrated by widespread microbialite sequences (disaster facies) in shallow water settings. Here we present high-resolution carbonate carbon ( ?13C carb) and carbonate-associated sulfate-sulfur isotope ( ?34S CAS) records from the microbialite in the Cili Permian-Triassic (P-Tr) section in South China. A stepwise decline in ?13C carb begins in the underlying skeletal limestone, predating the main oceanic mass extinction and the first appearance of microbialite, and reaches its nadir in the upper part of the microbialite layer. The corresponding ?34S CAS, in the range of 17.4‰ to 27.4‰, is relatively stable in the underlying skeletal limestone, and increases gradually from 2 m below the microbialite rising to a peak at the base of the microbialite. Two episodes of positive and negative shifts occurred within the microbialite layer, and exhibit a remarkable co-variance of sulfur and carbon isotope composition. The large amplitude of the variation in ?34S CAS, as high as 7‰ per 100 kiloyears, suggests a small oceanic sulfate reservoir size at this time. Furthermore, the ?13C carb and ?34S CAS records co-vary without phase lag throughout the microbialite interval, implying a marine-driven C cycle in an anoxic ocean with anomalously low oceanic sulfate concentrations. On the basis of a non-steady-state box model, we argue that the oceanic sulfate concentration may have fallen to less than 15%, perhaps as low as 3%, of that in the modern oceans. Low oceanic sulfate concentration likely was the consequence of evaporite deposition and widespread anoxic/sulfidic conditions prior to the main mass extinction. By promoting methanogenesis and a build-up of atmospheric CH 4 and CO 2, low oceanic sulfate may have intensified global warming, exacerbating the inimical environmental conditions of the latest Permian.

Luo, Genming; Kump, Lee R.; Wang, Yongbiao; Tong, Jinnan; Arthur, Michael A.; Yang, Hao; Huang, Junhua; Yin, Hongfu; Xie, Shucheng

2010-11-01

310

Permian collisional termination of the accretionary Central Asian orogenic belt, Inner Mongolia, China  

Science.gov (United States)

The East-West Central Asian Orogenic Belt (CAOB) extends across the China-Mongolia border into Inner Mongolia where the Solonker suture records the termination of the orogenic belt. The structure and development of the Solonker suture and its associated rocks are poorly understood. We report new field and structural data for the suture, and for the wider suture zone extending from the southern Mongolia cratonic boundary to the North China craton, and place them in the context of a tectonic evolution from the Late Precambrian to the Early Triassic. Our section is constrained by a seismic profile. The southern accretionary zone between the North China Craton and the Solonker suture is characterized by the Mid-Ordovician-Early Silurian Ulan island arc-Ondor Sum subduction-accretion complex and the Bainaimiao arc. This zone was consolidated by the Carboniferous-Permian when it evolved into an Andean-type magmatic margin above a south-dipping subduction zone. The northern accretionary zone between the Solonker suture and the growing Mongolian cratonic boundary extends southwards from a Devonian to Carboniferous active continental margin, through the Hegenshan ophiolite-arc accretionary complex to the Late Carboniferous Baolidao arc associated with some accreted Precambrian blocks. This northern zone had consolidated by the Permian when it developed into an Andean-type magmatic margin above a north-dipping subduction zone. Final subduction of the Central Asian Ocean caused the two opposing active continental margins to collide, leading to formation of the Solonker suture in the end-Permian. Predominant northward subduction during final formation of the suture gave rise in the upper northern plate to a large-scale, post-collisional, south-directed thrust-and-fold belt in the Triassic-Jurassic. In summary, the CAOB underwent three final stages of tectonic development: early Japanese-type accretion, Andean-type magmatism, and Himalayan-type collision.

Windley, B.; Xiao, W.

2003-04-01

311

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

312

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

International Nuclear Information System (INIS)

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

313

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

314

Earlier River Basin Planning  

...North Western River Basin...Member State Law. Identify River Basin Districts, International River Basin Districts and competent authorities....River and Lake Small Water Body Identification (.PDF 284Kb)...

315

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1996-12-31

316

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1996-01-01

317

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

318

The origin and early evolution of Sauria: reassessing the permian Saurian fossil record and the timing of the crocodile-lizard divergence.  

Science.gov (United States)

Sauria is the crown-group of Diapsida and is subdivided into Lepidosauromorpha and Archosauromorpha, comprising a high percentage of the diversity of living and fossil tetrapods. The split between lepidosauromorphs and archosauromorphs (the crocodile-lizard, or bird-lizard, divergence) is considered one of the key calibration points for molecular analyses of tetrapod phylogeny. Saurians have a very rich Mesozoic and Cenozoic fossil record, but their late Paleozoic (Permian) record is problematic. Several Permian specimens have been referred to Sauria, but the phylogenetic affinity of some of these records remains questionable. We reexamine and review all of these specimens here, providing new data on early saurian evolution including osteohistology, and present a new morphological phylogenetic dataset. We support previous studies that find that no valid Permian record for Lepidosauromorpha, and we also reject some of the previous referrals of Permian specimens to Archosauromorpha. The most informative Permian archosauromorph is Protorosaurus speneri from the middle Late Permian of Western Europe. A historically problematic specimen from the Late Permian of Tanzania is redescribed and reidentified as a new genus and species of basal archosauromorph: Aenigmastropheus parringtoni. The supposed protorosaur Eorasaurus olsoni from the Late Permian of Russia is recovered among Archosauriformes and may be the oldest known member of the group but the phylogenetic support for this position is low. The assignment of Archosaurus rossicus from the latest Permian of Russia to the archosauromorph clade Proterosuchidae is supported. Our revision suggests a minimum fossil calibration date for the crocodile-lizard split of 254.7 Ma. The occurrences of basal archosauromorphs in the northern (30°N) and southern (55°S) parts of Pangea imply a wider paleobiogeographic distribution for the group during the Late Permian than previously appreciated. Early archosauromorph growth strategies appear to be more diverse than previously suggested based on new data on the osteohistology of Aenigmastropheus. PMID:24586565

Ezcurra, Martín D; Scheyer, Torsten M; Butler, Richard J

2014-01-01

319

Implications from zircon-saturation temperatures and lithological assemblages for Early Permian thermal anomaly in northwest China  

Science.gov (United States)

Despite considerable efforts, the Paleozoic tectonic setting (subduction vs. post-collision vs. mantle plume) in the Central Asian Orogenic Belt (CAOB) remains controversial. With aims of solving this issue, we examined zircon saturation temperatures of granitoids emplaced in different settings, and demonstrated that zircon saturation thermometry of felsic igneous rocks, especially when integrated with their lithology and geochemistry, can be a simple and powerful tool for tectonic discrimination. This method is then applied in northern Xinjiang where the Early Permian granitoids have higher saturation temperatures (> 800 °C) than the Silurian-Carboniferous granitoids (mainly Silurian-Carboniferous to an intra-plate setting since Early Permian.

Liu, Hai-Quan; Xu, Yi-Gang; He, Bin

2013-12-01

320

Subsidence of the West Siberian Basin: Geophysical evidence for eclogitization  

Science.gov (United States)

The West Siberian basin is the world's largest intracratonic sedimentary basin. The basin basement consists of complexes of island arcs, terranes, micro-continents, and relict ocean basins which amalgamated during late Proterozoic-Paleozoic orogenic events up to the formation of the Pangea super-continent. The basin was affected by rifting and flood basalt eruption in the Permian-early Triassic (ca 250 Ma), which was floowed by rapid late Triassic (190 Ma) subsidence, as observed in borehole data from the axial part of the Ob rift (Saunders, 2005). Widely distributed subsidence of the north and central parts of the basin took place in the Jurassic with accumulation of 1,5- 3 km sediments. Two other subsidence episodes in the early Cretaceous and in the Late Cretaceous to Cenozoic led to deposition of 2-3 km of sediment in the north-eastern and axial parts. (Rudkevich, 1976). Most of the present-day West Siberian basin lacks surface topography, whereas the reliefs of the Moho and the top of the basement have amplitudes of ca. 20 km and 15 km, respectively (Cherepanova et al., 2012). Modeling suggests that the thermal lithosphere is 130km thick in the West Siberian basin, up-to 260 km in the Siberian craton further east, and 90 km in the axial part of the basin under the Ob rift (Artemieva and Mooney, 2001). Assuming local isostatic equilibrium and no effect of dynamic topography (which probably is a valid approximation for most of the region, except for the southern margin and the Urals), we examine the relative contributions of the crust and the lithospheric mantle to maintaining the surface topography. Lithosphere buoyancy is controlled by thicknesses and densities of the crust and the lithospheric mantle, and therefore by composition, metamorphic state, and temperature. Crustal thickness and density are constrained by our new regional crustal model, which is based on a quality-controlled compilation of all seismic models published in international and Russian literature, theses and reports since the 1970s (Cherepanova et al., 2012). Lithosphere thickness and temperature (which are interrelated parameters) are constrained by the thermal model. Our results indicate the presence of a large high-density anomaly in the upper mantle below the axial part of the basin. This result is supported by the seismic velocity variation in the mantle along two ultra-deep Soviet PNE reflection/refraction profiles and with the regional subsidence history and stretching factors. We suggest that this density anomaly is caused by eclogitization, and that the density increase from this process may explain a substantial part of the subsidence of the West Siberian Basin.

Cherepanova, Yulia; Artemieva, Irina M.

2013-04-01