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Sahni, Ashok
- Antecedants of Early Man in Nortifwestern India: Paleontological and Paleoecological Evidences
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PDF Views:125
Authors
Affiliations
1 Panjab University, Chandigarh 160014, IN
1 Panjab University, Chandigarh 160014, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 28, No 1 (1986), Pagination: 63-63Abstract
No Abstract.- Cretaceous-Tertiary Boundary Events: The Fossil Vertebrate, Palaeomagnetic and Radiometric Evidence from Peninsular India
Abstract Views :221 |
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Authors
Ashok Sahni
1,
Sunil Bajpai
1
Affiliations
1 Centre of Advanced Study in Geology, Panjab University, Chandigarh 160014, IN
1 Centre of Advanced Study in Geology, Panjab University, Chandigarh 160014, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 32, No 5 (1988), Pagination: 382-396Abstract
Recent data based on microvertebrates and associated microfossils suggest that the Lameta and coeval formations of Peninsular India are younger (Maestrichtian) than ages previously assigned to them (Cenomanian-Turonian). Similarly, the Takli and their intertrappean correlatives in several localities have yielded dinosaurian elements indicating thereby a Cretaceous rather than Tertiary age. Furthermore, no exclusively Tertiary taxa has been recorded from these beds at Nagpur, Asifabad, Kachchh and adjoining areas. Samples collected for palaeomagnetic studies with reference to vertebrate-bearing horizons suggest that the Deccan basaltic activity was initiated in the Late Maestrichtian at the end of Lameta times. The major part of the eruption took place during the reversed magnetic chron, 29R, which encompasses the Cretaceous-Tertiary Boundary. Radiometric dates (K/Ar, 40Ar/39Ar) tend to cluster in a 60 m.y. 70 m.y. interval. The Deccan traps have been cited as a possible alternative source of Ir enrichment in comparison to the hypothesis which ascribes the anomalously high values of this element at the KTB to an extra-terrestrial impact. The gradual decline of dinosaurs as well as other marine plankton and benthos towards the close of the Cretaceous favours hypotheses that do not advocate 'instantaneous' global mass extinctions.- Proceedings of the Thematic Workshop on Major Stratigraphic Boundries-High Resolution, Facies Controlled, Integrated Programme
Abstract Views :181 |
PDF Views:130
Authors
Affiliations
1 Centre of Advanced Studies in Geology, Panjab University, Chandrgarh, IN
2 Post Graduate of Department of Geology University of Jammu, Jammu, IN
3 Department of Science and Technology New Delhi, IN
1 Centre of Advanced Studies in Geology, Panjab University, Chandrgarh, IN
2 Post Graduate of Department of Geology University of Jammu, Jammu, IN
3 Department of Science and Technology New Delhi, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 39, No 2 (1992), Pagination: 180-181Abstract
No Abstract.- Fossil Turtle Eggshells From Infratrappean Beds of Duddukuru, Andhra Pradesh
Abstract Views :184 |
PDF Views:176
Authors
Affiliations
1 Department of Earth Sciences University of Roorkee, Roorkee-247667, IN
2 Department of Geology, Bangalore University, Bangalore-560056, IN
3 Department of Geology, Panjab University, Chandigarh-160014, IN
1 Department of Earth Sciences University of Roorkee, Roorkee-247667, IN
2 Department of Geology, Bangalore University, Bangalore-560056, IN
3 Department of Geology, Panjab University, Chandigarh-160014, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 49, No 2 (1997), Pagination: 209-213Abstract
Chelonian fossil eggshell fragments are reported from the Late Cretaceous Infratrappean beds near Duddukuru, West Godavari District, Andhra Pradesh.- Pictorial Catalogue of Siwalik Vertebrate Fossils from Northwest Himalaya
Abstract Views :185 |
PDF Views:124
Authors
Affiliations
1 CAS in GeoLogy, Panjab University, Chandigarh - 160014, IN
1 CAS in GeoLogy, Panjab University, Chandigarh - 160014, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 61, No 6 (2003), Pagination: 752-753Abstract
No Abstract.- An Introduction to The Mammalian Fauna of the Siwalik System: Biodiversity of the Siwalik Fauna
Abstract Views :178 |
PDF Views:134
Authors
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 58, No 2 (2001), Pagination: 188-188Abstract
No Abstract.- Oxygen Isotope Analysis of Bone and Tooth Enamel Phosphate from Paleogene Sediments: Experimental Techniques and Initial Results
Abstract Views :204 |
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Authors
Affiliations
1 Department of Geology and Geophysics, Indian Institute of Technology, Kharagpur - 721 302, IN
2 Department of Geology and Geophysics, Indian Institute of Technology, Kharagpur -721 302, IN
3 Wadia Institute of Himalayan Geology, Dehradun - 248 001, IN
4 Centre of Advanced Study in Geology, Panjab University, Chandigarh - 160 014, IN
1 Department of Geology and Geophysics, Indian Institute of Technology, Kharagpur - 721 302, IN
2 Department of Geology and Geophysics, Indian Institute of Technology, Kharagpur -721 302, IN
3 Wadia Institute of Himalayan Geology, Dehradun - 248 001, IN
4 Centre of Advanced Study in Geology, Panjab University, Chandigarh - 160 014, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 76, No 3 (2010), Pagination: 275-282Abstract
Oxygen isotope composition (δ18O) of fossil bone and tooth enamel phosphate (bioapatite) is an important tool for estimating the isotopic composition of past environmental water. Lack of analytical facility was a hindrance for studying such bioapatites in spite of large number of fossil materials reported from various geological ages in India. We have established in our laboratory, based on available methods, the chemical procedure for extraction of very small amount (<1000 μg) PO4 -3 from bioapatite and on-line mass spectrometric measurement of its δ18O composition by high temperature (∼1450 °C) pyrolysis. The achieved precision is ∼± 0.3 ‰ similar to obtained elsewhere, with interlaboratory calibration showing excellent agreement of standard phosphates. Inferred δ18O values of environmental water, based on the analysis of teeth and bones of sharks, fish and terrestrial mammals from the Paleogene successions of the northwest sub-Himalayan and the Peninsular India show strong correspondence with animal habitats. The freshwater δ18O values are much depleted having range similar to modern monsoon precipitation. However, owing to our small dataset it is not possible at this stage to infer about the existence of monsoon over the Indian sub-continent during the Eocene-Oligocene time.Keywords
Phosphate, Pyrolysis, Oxygen Isotope, Monsoon.- Siwalik Insectivora
Abstract Views :212 |
PDF Views:155
Authors
Affiliations
1 Department of Geology, Lucknow University, IN
1 Department of Geology, Lucknow University, IN