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Chondrites isp. indicating late paleozoic atmospheric anoxia in Eastern Peninsular India.

Bhattacharya B, Banerjee S - ScientificWorldJournal (2014)

Bottom Line: Rhythmic sandstone-mudstone-coal succession of the Barakar Formation (early Permian) manifests a transition from lower braided-fluvial to upper tide-wave influenced, estuarine setting.Monospecific assemblage of marine trace fossil Chondrites isp. in contemporaneous claystone beds in the upper Barakar succession from two Gondwana basins (namely, the Raniganj Basin and the Talchir Basin) in eastern peninsular India signifies predominant marine incursion during end early Permian.Such anoxia is interpreted as intermittent falls in oxygen level in an overall decreasing atmospheric oxygenation within the late Paleozoic global oxygen-carbon dioxide fluctuations.

View Article: PubMed Central - PubMed

Affiliation: Department of Earth Sciences, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand 247667, India.

ABSTRACT
Rhythmic sandstone-mudstone-coal succession of the Barakar Formation (early Permian) manifests a transition from lower braided-fluvial to upper tide-wave influenced, estuarine setting. Monospecific assemblage of marine trace fossil Chondrites isp. in contemporaneous claystone beds in the upper Barakar succession from two Gondwana basins (namely, the Raniganj Basin and the Talchir Basin) in eastern peninsular India signifies predominant marine incursion during end early Permian. Monospecific Chondrites ichnoassemblage in different sedimentary horizons in geographically wide apart (~400 km) areas demarcates multiple short-spanned phases of anoxia in eastern India. Such anoxia is interpreted as intermittent falls in oxygen level in an overall decreasing atmospheric oxygenation within the late Paleozoic global oxygen-carbon dioxide fluctuations.

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(a) Map of eastern India showing the distribution of the Gondwana Basins. Note the location of the Raniganj Basin and the Talchir Basin. (b) Geological map of the north-western part of the Raniganj Basin, showing the distribution of different lithounits. (c) Detailed geological map of the central part of the Talchir Basin, showing the distribution of different lithounits. The legend shows the ages of the lithounits. Study areas are shown by rectangles in both the maps ((b) and (c)).
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fig1: (a) Map of eastern India showing the distribution of the Gondwana Basins. Note the location of the Raniganj Basin and the Talchir Basin. (b) Geological map of the north-western part of the Raniganj Basin, showing the distribution of different lithounits. (c) Detailed geological map of the central part of the Talchir Basin, showing the distribution of different lithounits. The legend shows the ages of the lithounits. Study areas are shown by rectangles in both the maps ((b) and (c)).

Mentions: Barakar Formation (early Permian) within the Gondwana sedimentary succession is the main coal-producing horizon in Indian Subcontinent. Earlier studies recorded a braided-meandering fluvial depositional system with peat-forming mires in the low-lying marshy floodplains that produced thick succession of sandstone-shale-coal cyclothems within the Barakar Formation [7]. Recent sedimentological analyses from multiple Gondwana basisn of India suggested strong influence of marine wave and tide on fluvial sedimentation during the deposition of middle-upper Barakar succession [8–10], indicating a fluvio-marine interactive deltaic/estuarine depositional setting. The Barakar Formation in the Raniganj Basin in the Koel-Damodar Valley and the Talchir Basin in the Mahanadi Valley (Figure 1), comprises of thick sandstone-shale-coal deposits (Figure 2) manifesting similar depositional history. The lower parts of the sedimentary successions in both the basins bear thick coal seams and represent braided-fluvial depositional setting (Figure 2).


Chondrites isp. indicating late paleozoic atmospheric anoxia in Eastern Peninsular India.

Bhattacharya B, Banerjee S - ScientificWorldJournal (2014)

(a) Map of eastern India showing the distribution of the Gondwana Basins. Note the location of the Raniganj Basin and the Talchir Basin. (b) Geological map of the north-western part of the Raniganj Basin, showing the distribution of different lithounits. (c) Detailed geological map of the central part of the Talchir Basin, showing the distribution of different lithounits. The legend shows the ages of the lithounits. Study areas are shown by rectangles in both the maps ((b) and (c)).
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3926327&req=5

fig1: (a) Map of eastern India showing the distribution of the Gondwana Basins. Note the location of the Raniganj Basin and the Talchir Basin. (b) Geological map of the north-western part of the Raniganj Basin, showing the distribution of different lithounits. (c) Detailed geological map of the central part of the Talchir Basin, showing the distribution of different lithounits. The legend shows the ages of the lithounits. Study areas are shown by rectangles in both the maps ((b) and (c)).
Mentions: Barakar Formation (early Permian) within the Gondwana sedimentary succession is the main coal-producing horizon in Indian Subcontinent. Earlier studies recorded a braided-meandering fluvial depositional system with peat-forming mires in the low-lying marshy floodplains that produced thick succession of sandstone-shale-coal cyclothems within the Barakar Formation [7]. Recent sedimentological analyses from multiple Gondwana basisn of India suggested strong influence of marine wave and tide on fluvial sedimentation during the deposition of middle-upper Barakar succession [8–10], indicating a fluvio-marine interactive deltaic/estuarine depositional setting. The Barakar Formation in the Raniganj Basin in the Koel-Damodar Valley and the Talchir Basin in the Mahanadi Valley (Figure 1), comprises of thick sandstone-shale-coal deposits (Figure 2) manifesting similar depositional history. The lower parts of the sedimentary successions in both the basins bear thick coal seams and represent braided-fluvial depositional setting (Figure 2).

Bottom Line: Rhythmic sandstone-mudstone-coal succession of the Barakar Formation (early Permian) manifests a transition from lower braided-fluvial to upper tide-wave influenced, estuarine setting.Monospecific assemblage of marine trace fossil Chondrites isp. in contemporaneous claystone beds in the upper Barakar succession from two Gondwana basins (namely, the Raniganj Basin and the Talchir Basin) in eastern peninsular India signifies predominant marine incursion during end early Permian.Such anoxia is interpreted as intermittent falls in oxygen level in an overall decreasing atmospheric oxygenation within the late Paleozoic global oxygen-carbon dioxide fluctuations.

View Article: PubMed Central - PubMed

Affiliation: Department of Earth Sciences, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand 247667, India.

ABSTRACT
Rhythmic sandstone-mudstone-coal succession of the Barakar Formation (early Permian) manifests a transition from lower braided-fluvial to upper tide-wave influenced, estuarine setting. Monospecific assemblage of marine trace fossil Chondrites isp. in contemporaneous claystone beds in the upper Barakar succession from two Gondwana basins (namely, the Raniganj Basin and the Talchir Basin) in eastern peninsular India signifies predominant marine incursion during end early Permian. Monospecific Chondrites ichnoassemblage in different sedimentary horizons in geographically wide apart (~400 km) areas demarcates multiple short-spanned phases of anoxia in eastern India. Such anoxia is interpreted as intermittent falls in oxygen level in an overall decreasing atmospheric oxygenation within the late Paleozoic global oxygen-carbon dioxide fluctuations.

Show MeSH
Related in: MedlinePlus