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P. K. Raha ¹, S. N. Parulkar ², S. C. Ghosh ³, S. Some ³, U. S. Kundu ³, Manoj Kumar ⁴, G. Saha ⁴, I. K. Misra ⁴

Affiliations
1 Coal Wing, Geological Survey of India, Calcutta, IN
2 Geological Survey of India, Raipur, IN
3 Geological Survey of India, Calcutta, IN
4 Geological Survey of India, Nagpur, IN

Abstract

SEM studies have recorded presence of filamentous and unicellular spheroidal structures which are regarded as "possible microfossils", from the stromatolitic Archaean (ca. 3.0 Ga old) banded iron formation (BIF), Bailadila Group. Spheroidal bodies have diameters that range from 0.5 to 6.9 microns. The frequency of forms with smaller diameters is greater than those with the diameter above 3.0μm. The filamentous structures range from less than 100 nanometres to 1.2μm in diameter. Syngenetic nature of these microfossils has been established. Though a large number of these microfossils could be identified in the SEM, they could not be observed in petrographic thin sections under optical microscope most probably because of their association with, and being clouded by, opaque haematite.

Keywords

Archaean, Banded Iron Formation, Bailadila Group, Bastar District, Madhya Pradesh.

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P. K. Raha ¹

Affiliations
1 Geological Survey of India, Calcutta, IN

Abstract

No Abstract.

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P. K. Raha ¹, M. C. Chandy ¹, M. N. Balasubrahmanyan ¹

Affiliations
1 Geological Survey of India, Calcutta, IN

Abstract

No Abstract.

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P. K. Raha ¹

Affiliations
1 Geological Survey of India, Calcutta 700 016, IN

Abstract

No Abstract.

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P. K. Raha , S. Sinha Roy , C. P. Rajendran

Abstract

A lithostratigraphic classification of the Cenozoic sedimentary sequence of the coastal plains of Kerala has been developed through an analysis of the exposed and subcrop litho-facies and their interrelationship based on sedimentologic parameters. The entire Cenozoic sequence is designated as the Malabar Supergroup comprising the Vembanad Formation (Quaternary-Holocene) and the Warkalli Group (Tertiary) separated by an unconformity marked by laterite. The Warkalli Group comprises the Ambalapuzha, the Quilon and the Mayyanad Formations from top to bottom. The Ambalapuzha and the Mayyanad Formations are basin margin fluvial and deltaic facies comprising sandstones, clays and lignites, and having a wedge of calcareous platform facies of the Quilon Formation. With the thinning out of the Quilon Formation (calcareous facies) in the eastern margin of the basin, the distinction between the constituent formations of the Warkalli Group disappears. Thus the purely terrigenous sediments in the eastern and southern margins of the basin form a single non-classifiable unit, the Warkalli Formation.

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P. K. Raha ¹, C. P. Rajendran ², R. K. Kar ³

Affiliations
1 Geological Survey of India, Calcutta, IN
2 Centre for Earth Science Studies, Trivandrum, IN
3 Birbal Sahni Institute of Palaeobotany, Lucknow, IN

Abstract

Eocene palynofossils are reported for the first time from a bore hole core drilled near Ambalapuzha in Alleppey District, Kerala between the depths of 400-571 m. Characteristic pollen genera recovered are: Palmaepollenites, Couperipollis, Proxapertites, Meliapollis, Striacolporites, Retistephanocolpites etc.

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C. P. Rajendran ¹, P. K. Raha ², M. K. Sen ²

Affiliations
1 Centre for Earth Science Studies, Trivandrum, IN
2 Geological Survey of India, Calcutta, IN

Abstract

The occurrence of Actinosiphon sp. a larger foraminifera, obtained from the subcrop section at Ambalapuzha, at a depth of 454-494 m is reported. This find further confirms the presence of Eocene sediments in the onshore Kerala sedimentary basin.

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D. P. Das ¹, P. K. Raha ¹, S. K. Acharyya ¹

Affiliations
1 Geological Survey of India, Calcutta 700016, IN

Abstract

Two tiny carapaces having strong resemblance to Ostracoda are reported from the basal part of the upper Krol Formation occurring in the Nainital Synform of U. P. Himalaya. These ostracode forms are present in close association with several forms of shelly microfauna distinctive of Tommotian (early Cambrian) time. The characteristic features of these two forms representing the oldest ostracodes of the Indian subcontinent are described.

Keywords

Palaeontology, Ostracoda, Krol Formation, Nainital, Kumaun Himalaya.

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