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Chatterjee, T. K.
- Age of Deccan Volcanism Across KTB in Krishna-Godavari Basin: New Evidences
Authors
1 Geological Laboratories, KDM Institute of Petroleum Exploration, ONGC, Kaulagarh Road, Dehra Dun - 248195, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 45, No 2 (1995), Pagination: 229-233Abstract
The latest Paleontological data suggest that the duration of Deccan trap eruption in Krishna-Godavari basin varies from place to place and could be anywhere between <0.5 Ma and 6 Maacross KTB. Three groups of fossils viz., Planktic foraminifera, Nannoplanktics and Dinoflagellate cysts suggest that the initiation of volcanism was during latest Maastrichtian within the upper part of Abathomphalus mayaroensis Zone, Micula murus Zone and Triblastula utinensis Zone between 67 and 66.5 Ma. There are conflicting evidences in dating the upper age limit of the volcanics probably due to diverse methods employed in calibration of forarniniferal and nannoplanktic scales or selective retrieval of very small sized planktics of zones P0 and P1 in well cuttings.Keywords
Micropalaeotogy, Deccan Volcanism, Age, Krishna-Godawari Basin.
- Integrated Foraminiferal and Ammonoid Biostratigraphy of Jurassic Sediments in Jaisalmer Basin, Rajasthan
Authors
1 Paleontology Laboratory, KDMlPE, ONGC, Kaulagarh Road, Dehra Dun-248 195, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 47, No 4 (1996), Pagination: 477-490Abstract
In the Post-Vindhyan times, major marine transgressions covered the areas of Kutch and Rajasthan, including the Jaisalmer Basin during Jurassic, although minor Permian transgressions are also known. These events could be documented from the well known exposures of Kutch and Rajasthan which entombed classic Cephalopod fauna. The foraminiferal components of Kutch Mesozoic were catalogued by Pandey and Dave (1993), recognizing 13 benthic foraminiferal biozones, establishing 8 chronostratigraphic units (stages).
Within the outcropping marine Middle-Upper Jurassic succession of Jaisalmer, seven benthic foraminiferal zones have been recognized and correlation with Kutch Mesozoic established. However, the succession is interrupted by five hiatuses during - (1) Upper Bathonian, (2) Upper Callovian - Lower Oxfordian, (3) Upper Oxfordian - Lower Kimmeridgian, (4) Middle Kimmeridgian and (5) Upper Kimmeridgian - Lower Tithonian.
Trangressive events during Lower Bathonian, Lower Callovian, Middle - Upper Oxfordian and Lower Kimmeridgian with intervening regressive pulses are also recorded.
Badian, Charian, Dhosaian, Katrolian and Umiaian stages of Kutch ranging in age from Bathonian to Tithonian are recognized.