1995-96 - Birbal Sahni Institute of Palaeobotany
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1995-96 - Birbal Sahni Institute of Palaeobotany

1995-96 - Birbal Sahni Institute of Palaeobotany 1995-96 - Birbal Sahni Institute of Palaeobotany

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BSIP Palynological analysis of 250 m deep Sadanandpur profile, dating back to 160 ka yrs B. P., has been completed. It is the first attempt to present the palaeorecords of marine palynology of the complete Quaternary sediments from Mahanadi delta in Orissa. Pollen diagrams one each in curve and bar have been prepared. The whole pollen diagram has been classified into 12 pollen zones and 6 barren zones in view to cxpress the finer biostratigraphic units and to demarcate significant epochs and events since the time of deposition of these sediments The pollen evidence has revealed several cyclic changes in thc marine transgressive and regressive facies which are recorded between depth of236-250 m, 218-223 m and 170-211 m and the sea marginal conditions are recorded at the depth of 53­ 142 m. The sanlples between the depths mentioned above have rcvealcd the preponderance of core-mangrove taxa such as Rhizophora, Ceriops, Bruguiera, Xylocarpus, Aegialitis rotundifolia, Excoecaria agaljocha, Avicennia, Sonneratia, Heritiera, etc. indicating the marine facies with constant depths of sea-water. However, the samples between 48-50 m depth have recorded fresh/brackish water pollen suggesting marine regression resulting into the development of salt marshes. The age for the above events are extrapolated to 160 ka, 140 ka, and 90 ka, rcspectively. On the basis of litho- and palynostratigraphy, the ancient shore lines have been suggested across the De1ang-Jagatsingharpur-Balasore. The pollen diagrams of Chandrapur and Geokhala profiles (3.0 m each in depth) havc been prepared through the TILIA computer software. Four photoplates have been prepared for recovered palynodata from the aforesaid profiles. S.P. II Palaeogene floral palaeoenvironmental 93) H.P. Gupta & Deepak Kohli diversity-biostratigraphy and implications (DST NO. ES/441037/ Objeclives To document the palynological changes during Palaeogene To decipher the extinction and evolutionary pattern of the different palynotaxa To infer the palaeoecological condition of deposition A number of bore-hole corcs supplied by the MECL and GSI from the various localities of Bikaner District, Rajasthan were chemically processed. A rich palynological assemblage comprising mostly pteridophytic spores and angiospennic pollen was recovered. The dominant species are Dandotiaspora dilala, Lycopodiumsporites specioslls, Spinizonocolpites echinatus, Piladiporocolpiles caratinii, Tricolpites reticll/atus, neocouperipol/is kutchensis, Retidiporoco/pites excel/emus, Proxapertites operculatus, Ocimumpollenites indicus, etc. Besides, 13 bore-hole core samples drilled by the DGM, Gujarat in Surat and Bhavnagar districts were also macerated. Out of 220 samples, 78 samples were productive and the slides of these samples were prepared. R.K. Kar, Poonam Sharma & Reema Singh S.P. III Reconstruction of past climatic changes in eastern Himalayan region using tree-ring data (DST No. ES/44/018/90) 128

1995-96 Objective To understand past climatic changes especially temperature and precipitation during last 500 years based on tree-ring width proxy data Tree ring cores were studied through Cross-dating technique and each ring of tree ring series was assigned the calendar year of its fomlation. Same taxa have been found most promising for constructing climatic sensitive tree ring chronology and further dendroclimatic analysis. Dated tree ring sequences of several conifer taxa were measured by the ring width measuring machine and ring width index chronology· were prepared. Statistical analysis between tree ring data and metwrologieal data of sampling sites or nearest station was done to understand the tree growth and climate relationship. S.P. IV Objective A. Bhattaeharyya, R.R. Yadav & Vandana Chaudhary Palaeo biological investigations across Archaeozoic-Early Proterozoic transition (DST NO. ESS/CA/A4-09/93) To identifY organic-walled microfossils, their syngenicity and biogenicity from Archaean and Early Proterozoic Identification of benthic and planktonic biota and their comparison with extant forms Significance of biota in metallogenesis Organosedimentary structures-stromatolite morphology. etc. Study of organic walled microfossils associated with stromatolites Significance of stromatolites in biostratigraphy, basin analysis, etc. The Iron Ore Group exposed in Barbil-Noamundi area has been subdivided into two lithostratigraphical units: Kashia Fomlation and Barbil Formation. The Kashia Formation is well exposed in Kashia mine about 10 km from Barbi!. It is basically an argillo-calcareous lithounit with well developed stromatolite horizons and fossiliferous chert horizon. It has been further subdivided into 7 units. It shows well developed structures and on this basis intertidal to subtidal zone of a lagoon has been suggested as the environment of deposition for the Kashia Formation. Sandstone dykes have been recorded from the uppermost part of the Kashia Formation. TIlis is the first record of sandstone dyke from Archaean of India. The Kash.ia Formation has been followed upward possibly with an uneonfomlity by a conglomeratic sandstone of the Barbil Formation. The sandstone is followed upward by a stronlatolite unit. A shale unit succeeds stromatolite unit. The shale grades into a thick Haematite-Jasper-Chert Unit. This horizon is being mined for Iron Ore and Manganese deposits. In the carbonate sequence Conophyton appears to be the most common columnar stromatolites alongwith Colonel/a type forms. The height of the stromatolite col­ UI1Ulis up to few centimeters. 129

<strong>1995</strong>-<strong>96</strong><br />

Objective To understand past climatic changes especially temperature<br />

and precipitation during last 500 years based on tree-ring width<br />

proxy data<br />

Tree ring cores were studied through Cross-dating technique and each ring <strong>of</strong> tree<br />

ring series was assigned the calendar year <strong>of</strong> its fomlation. Same taxa have been found most<br />

promising for constructing climatic sensitive tree ring chronology and further dendroclimatic<br />

analysis. Dated tree ring sequences <strong>of</strong> several conifer taxa were measured by the ring width<br />

measuring machine and ring width index chronology· were prepared. Statistical analysis<br />

between tree ring data and metwrologieal data <strong>of</strong> sampling sites or nearest station was done<br />

to understand the tree growth and climate relationship.<br />

S.P. IV<br />

Objective<br />

A. Bhattaeharyya, R.R. Yadav & Vandana Chaudhary<br />

Palaeo biological investigations across Archaeozoic-Early Proterozoic<br />

transition (DST NO. ESS/CA/A4-09/93)<br />

To identifY organic-walled micr<strong>of</strong>ossils, their syngenicity and<br />

biogenicity from Archaean and Early Proterozoic<br />

Identification <strong>of</strong> benthic and planktonic biota and their comparison<br />

with extant forms<br />

Significance<br />

<strong>of</strong> biota in metallogenesis<br />

Organosedimentary structures-stromatolite morphology. etc.<br />

Study <strong>of</strong> organic walled micr<strong>of</strong>ossils associated with stromatolites<br />

Significance <strong>of</strong> stromatolites in biostratigraphy, basin analysis,<br />

etc.<br />

The Iron Ore Group exposed in Barbil-Noamundi area has been subdivided into two<br />

lithostratigraphical units: Kashia Fomlation and Barbil Formation. The Kashia Formation<br />

is well exposed in Kashia mine about 10 km from Barbi!. It is basically an argillo-calcareous<br />

lithounit with well developed stromatolite horizons and fossiliferous chert horizon. It<br />

has been further subdivided into 7 units. It shows well developed structures and on this<br />

basis intertidal to subtidal zone <strong>of</strong> a lagoon has been suggested as the environment <strong>of</strong><br />

deposition for the Kashia Formation. Sandstone dykes have been recorded from the uppermost<br />

part <strong>of</strong> the Kashia Formation. TIlis is the first record <strong>of</strong> sandstone dyke from Archaean<br />

<strong>of</strong> India.<br />

The Kash.ia Formation has been followed upward possibly with an uneonfomlity by<br />

a conglomeratic sandstone <strong>of</strong> the Barbil Formation. The sandstone is followed upward by a<br />

stronlatolite unit. A shale unit succeeds stromatolite unit. The shale grades into a thick<br />

Haematite-Jasper-Chert Unit. This horizon is being mined for Iron Ore and Manganese<br />

deposits. In the carbonate sequence Conophyton appears to be the most common<br />

columnar stromatolites alongwith Colonel/a type forms. The height <strong>of</strong> the stromatolite col­<br />

UI1Ulis up to few centimeters.<br />

129

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