Journal of Geological Society of India (Online archive from Vol 1 to Vol 78)

R. K. Kar ¹, K. Ambwani ¹, D. Dutta ¹, Ratan Kar ¹

Affiliations
1 Birbal Sahni Institute of Palaeobotany, 53, University Road, Lucknow - 226 007, IN

Abstract

The Um Sohryngkew river section at Therriaghat, Meghalaya, exposes Mahadeo (Maastrichtian) and Langpar (Danian) Formations extensively. The palynological investigation of the topmost Mahadeo and lowermost Langpar reveals an abrupt change in palynoflora at the formational boundary. The Maastrichtian index palynofossils viz. Azolla cretacea, Ariadnaesporites ariadnae, Mulleripollis bolpurensis etc. disappear at the uppermost Mahadeo. At the basal Langpar the assemblage is dominated by fungal and algal elements. On this basis the palynofacies turnover is demarcated within a 40 cm thick calcareous sandy shale underlain by the 3 cm thick highly carbonized shale. The palynological boundary corresponds with the lithological one demarcated by Pandey(1978, 1981), and is located 10 m above the foraminiferal, nannofossil, dinoflagellate boundary approximating the iridium rich level. The palynological data suggest no major catastrophic event at the iridium level with the major taxa continuing through. The major palynological break reported in this paper is at formational boundary and may be facies controlled as well.

Keywords

Palynology, Mahadeo-Langpar Formations, Iridium Layer, K/T Boundary, Um Sohryngkew River, Meghalaya.

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R. Arya ¹, K. Ambwani ², Neera Sahni ¹, A. Sahnj ¹

Affiliations
1 Centre of Advanced Study in Geology, Panjab University, Chandigarh - 160 014, IN
2 2Birbal Sahni Institute of Palaeobotany, Lucknow - 226 007, IN

Abstract

The Kasauli Formation represents the initial stage of development of the foreland basin in response to the rising Himalaya. Here we report for the first time, a mammal (Rhinoceratidae, gen. et sp. indet) and some new taxa of fossil flowers from two localities, Shiv Mandir and Water Tank. The Kasauli Formation comprises of a grey/green, sometimes highly carbonaceous shale and massive grey/green sandstone sequence which so far has lacked an age- diagnostic biotic assemblage. The presence of a rhinoceratid, commonly known from other coeval sections of the Lower Murree in Pakistan and the Kalakot region, suggests the potential of finding suitable palaeontological temporal constraints for the fossil-bearing horizons. Two new taxa of fossil flowers, Kasaulipushpam and Trilobanthus are described. The present data suggests the presence of a well-watered landscape during Kasauli times in sharp contrast to more arid condition in the underlying Dagshai Formation which is predominantly red in colour.

Keywords

Mammal, Fossil Flowers, Lower Miocene, Kasauli, Himachal Pradesh.

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