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P. K. Maithy ¹, Rupendra Babu ¹

Affiliations
1 Birbal Sahni Institute of Palaeobotany, Lucknow 226 007, IN

Abstract

Macrobiota comprising body fossils and trace fossils are reported from the Semri and Kaimur Groups of the Vindhyan Supergroup exposed around Chopan. Carbonaceous compressions of Chuaria minima and Tawuia dalensis, impressions of Sekwia excentrica and moulds of Longfengsahnia chopanensis sp. nov. are reported from the Rohtas Limestone Formation, Semri Group. Beside these, Longfengsahnia stiplala and epirelief of trace fossils belonging to possibly annelids are reported from the Ghurma Shale Formation of Kaimur Group. The macrobiota record indicates that during the Rohtas time free planktonic forms were present in the entire Vindhyan region particularly the genus Chuaria which may be considered as an index fossil of that period.

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Naresh C. Mehrotra ¹, Rupendra Babu ¹, Rajni Tewari ¹, Neerja Jha ¹, Prabhat Kumar ², Veeru Kant Singh ¹, Manoj Shukla

Affiliations
1 Birbal Sahni Institute of Paleobotany, 53, University Road, Lucknow-226007, IN
2 Zoology Department, Lucknow University, Lucknow-226007, IN

Abstract

First record of Type I matured, Liptinite organic matter facies from the Gotan Limestone (Late Neoproterozoic) in Rajasthan is considered significant. This throws open an entirely new basin for hydrocarbon exploration from the Neoproterozoic sediments in Rajasthan and other similar prospective basins in India. The palynological assemblage recorded from the studied samples also contains larve of the petroleum fly Helaeomyia (=Psilopa Coquillet) petrolei, known to live in pools of crude petroleum. The significance of the find is discussed in this brief communication.

Keywords

Hydrocarbon Exploration, Neoproterozoic Basins, Rajasthan.

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Manoj Shukla ¹, Rupendra Babu ¹, V. K. Mathur ², D. K. Srivastava ²

Affiliations
1 Birbal Sahni institute of Palaeobotany, Lucknow - 226 007, IN
2 Palaeontology Division, Geological Survey of India, Northern Region, Lucknow - 226 024, IN

Abstract

Black carbonaceous shale associated with black chert nodules of Infra Krol Formation, Baliana Group yielded diversified assemblage comprising 20 taxa of Organic-walled microfossils (OWM) represented by acritarchs and cyanobacterial remains. Out of these, 16 taxa are reported for the first time from this area which include five genera of acritarchs (sphaeromorphida subgroup) viz. Margominuscula simple, Granomarginata primiriva, Satka colonialica, Paracrassosphaera dedalea, Microconcentrica incrustata, and six genera (sphaerohystrichomorphida subgroup) viz. Baltisphaeridium perrarum, trachyhystrichosphaera vidalii, Gorgonisphaeridium maximum, Micrhystridium echintiatum, M. regulare, M. eatonensis, Archaeohystrichosphaeridium cellulare, A. semireliculatum,Germinosphaera unispinosa; four taxa of the cyanobacterial remains viz. Globophycus rugosum, Bavlinella faveolata, Eomicrocystis inalgica, Tetraphycus hebeiensis, Eophormidium orculiformis belong to Synaplomorphitae subgroup and single genus of VSM viz, Melanocyrillium hexodiadema.

The recovered microbiotic assemblage compares well with the assemblages known from the Terminal Proterozoic sediments. The large sized acanthomoph Trachyhystrichosphaera vidalii, recorded here for the first time, is known globally after. Varanger glaciation and before diversification of Ediacaran biota. An analysis of the recovered microbiotic assemblage in the Infra Krol Formation suggests its autochthonous nature. It was deposited in stable, shallow water, restricted pond or lake which had occasional contact with the open sea.

Keywords

Terminal Proterozoic, Organic-Walled Rnicrofossils, Infra Krol Formation, Nainital Syncline, Uttaranchal

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