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D. P. Sen ¹

Affiliations
1 Department of Geology & Geophysics, Indian Institute of Technology, Kharagpur, IN

Abstract

The Lower Gondwana tillites overlying glaciated pavements has been reported from Irai in central India, south bank of Ajay river and Karanpura basin from eastern India. The pavement exposed at Jainti basin strongly supports glacial origin of the tillites. The general northerly direction of movement of ice has been suggested mainly from striations and step like features.

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S. N. Das ¹, D. P. Sen ²

Affiliations
1 Geological Survey of India, Calcutta., IN
2 Department of Geology, I.I.T., Kharagpur-721302, IN

Abstract

The Talchir Group of rocks in India form a very important stratigraphic horizon by their presence at the base of all the Gondwana basins. Talchirs have been recognised as glacial sediments. The present study suggests that the Talchir Group was deposited both as stratified drift and unstratified drift. The glaciers responsible for Talchir sedimentation in eastern India belong to piedmont glacier system. The number of times the glacial lobes advanced into different basins varies from basin to basin. In all the basins the bulk of the sediments was deposited during first deglaciation period as meltwater channel, esker, glaciolacustrine delta and lake deposits. The topography surrounding the basin during upper Talchir time provided infra-structure for Barakar sedimentation.

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D. P. Sen ¹

Affiliations
1 Department of Geology, I.I.T. Kharagpur 721302, West Bengal, IN

Abstract

Small scale ripple superimposed on large scale ripple have been observed in the Talchir rocks of Giridih basin. Both the small scale and large scale ripple observed are combined flow ripple with greater wave influence. The ripples were formed in wave agitated glacial lake.

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D. P. Sen ¹, S. N. Pradhan ²

Affiliations
1 Department of Geology and Geophysics I.I.T., Kharagpur, 721 302, IN
2 Department of Earth Science, Sambalpur University, P. O. Burla, Sambalpur, Orissa, IN

Abstract

Within the Talchir Group of rocks of the Talchir Gondwana basin occurs a step-like delta around village Simlipal. The older of the two delta sequences is characterised by interference of topset and foreset beds, sleep foreset slope (10° - 26°) and imperceptible delta slope break. Irregular shifting of lake level during the growth of the older delta, possibly controlled by weather variation from abnormally high temperature condition to cold, cloudy and dry conditions resulted in the formation of step-like delta. Delta front collapsed due to decay of stagnant buried ice which formed part of the basement over which delta grew and gave rise to small scale fold, fault and stump features. Younger delta with a prominent well developed foreset forming a Gilbert type delta developed over the older delta under a stable lake level condition. Two delta sequences together fanned the complete sequence of step-like delta.

Keywords

Talchir, Sedimentology, Delta, Gondwana Basin, Orissa.

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D. P. Sen ¹, Tapas Banerji ¹

Affiliations
1 Department of Geology and Geophysics, Indian Institute of Technology, Kharagpur - 721 302, IN

Abstract

Reconstruction of sedimentation pattern and palaeogeographic model during Talchir sedimentation in Jayanti Gondwna basin has been attempted in the present paper.

The Talchir rocks in the basin consist of three distinct facies assemblages : Finer facies assemblage (Unit I) representing lake bottom sediments emplaced by two sets of processes namely - suspension from sediments introduced into the lake by interflow and overflow currents and turbidity current triggered by slumping in lake floor and delta front.

Sandstone facies assemblage (Unit II) representing mainly low slope (∼5°) delta deposits. Channels, interchannel and bar sediments fonn the topset of the delta. The foreset beds are difficult to identify because of very low slope of the delta margin.

The upper coarser facies assemblages (Unit III) introduced into the lake by various glaciogenic processes. The most dominant process was range of gravity flow processes generated on the steeper slope in the subaerial part to the south of the lake margin. Sudden change of slope from steep in the subaerial part to gentle in the lake margin has restricted the distribution of the facies along the southern low slope lake margin.

The depositional model is that of a low slope, prograding glacio-fluvial delta advancing over glacio-lacustrine sediments. The model suggested is a modification of available glacio-lacustrine model of moderate to high slope glacial lakes.

Keywords

Sedimentology, Glaciation, Gondwana Basin, Damodar Valley.

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D. P. Sen ¹, Suman Krishna Sit ¹

Affiliations
1 Department of Geology and Geophysics, IIT, Kharagpur, West Bengal - 721 302, IN

Abstract

Armoured mud balls and till ball (sand ball) are reported for the first time from the Permocarboniferous Talchir Formation. The balls occur within a gullied part of the boulder bed. The balls found in the environment result from block breakage due to undercutting of a till face by meltwater stream and rolling during transportation. The unannoured spherical balls of diameter 3-14 cm composed of coarse materials are formed around tillite blocks and flat pebbles. whereas balls formed around clay or mud lumps are later armoured by grannule and pebble size clasts. The balls are termed till balls and mud balls respectively. Since the balls composed of coarse materials may also be derived from the environments other than glacial environments, it is appropriate to term these balls as sand ball.

Sand balls and mud balls along with associated primary structures may be used as palaeogeographic indicators. Presence of these balls and associated structures also reveal that though apparently the Boulder bed appear to be a single lithostratigraphic unit, in reality it is a complex of number of gravity flow deposits.

Keywords

Sedimentary Petrology, Talchir Gondwana, Sand Ball, Permo-Carboniferous, Orissa.

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D. P. Sen ¹, A. Hatim ¹

Affiliations
1 Department of Geology and Geophysics, Indian Institute of Technology, Kharagpur, W. Bengal, IN

Abstract

The sediments include glacial outwash plain, glacio-lacustrine delta and glacial lake deposits. Glaciers were probably of a piedmont type that existed towards the south and southwest of the basin. Melt water season seems to have dominated over winter season. Fluctuation in the ratio of melting controlled by short lived temperature variation resulted in the deposition of number of complete and incomplete sequences with draped lamination and ripple-drift cross lamination between two winter clay layers. The Palaeozoic sea which existed to the north of the basin was connected to the main basin at a late stage through a channel cut by glacier.

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K. V. L. Venkatesh ¹, S. Dhanaraj ¹, B. Mahadevaiah ¹, S. M. Ananthakrishna ¹, M. Mahadevaiah ¹, B. Anandaswami ¹, V. S. Govindarajan ¹, D. P. Sen ¹

Affiliations
1 Central Food Technological Research Institute, Mysore- 570 013, IN

Abstract

The important role played by the sweetmeats in the Indian dietary and their abundant use in festival seasons in particular needs no emphasis. Of late, the increase in exports of sweetmeats to other countries, especially to Middle East, has further enhanced their importance and added problems of packaging and storage.

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Grace George ¹, D. P. Sen ²

Affiliations
1 Department of Biochemistry, University of Benin, Ugbowo Campus, Benin city, Bendal State, NG
2 Central Food Technological Research Institute, Mysore 570 013, IN

Abstract

In an earlier communication, Grace George and Sen' have reported the preparation of a few interesterified vanaspati like plastic fats from refined and bleached sal fat, edible grade sheep tallow, vanaspati, refined groundnut oil, refined safflower oil and cottonseed oil.

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