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

P. K. Banerjee ¹

Affiliations
1 Department of Geological Sciences, Jadavpur University, Calcutta 700 032, IN

Abstract

No Abstract.

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P. K. Banerjee ¹, S. Ghosh ²

Affiliations
1 School of Oceanography, Jadavpur University, Calcutta-700 032, IN
2 Geological Survey of India, Calcutta-700 016, IN

Abstract

The Simlipal basic volcanics share two common features with the Newer Dolerite dyke swarm (within the Singhbhum-Keonjhar granite) and the Ongarbira volcanics and Dangoaposi lavas occurring along its western margin: their freedom from intense folding movements and from granite intrusion; although Simlipal's tectonic and chronologic frame with grits and sandstones alternating with basic volcanics still awaits solution. The geologic and isotope geochronologic data available from these suites do not rule out the possibility that these could be broadly contemporaneous eruptions and emplacements. Judging by the uniform spread of the dykes over approx. 20,000 sq·km of granite country, the forcing of all these eruptions by a plume head, spreading below the Singhbhum continental lithosphere near the transition between Proterozoic I and II is suggested as a tectonomagmatic model, to be tested in future against high resolution isotope geochronological dates and dependable REE and Nd-Sr geochemistry for defining the eruptive events of this terrain.

Keywords

Tectonics, Simlipal, Ongarbira, Dangoaposi lavas, Newer Dolerite, Proterozoic, Orissa, Bihar.

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P. K. Banerjee ¹, S. Goswami ¹, S. Chatterjee ¹

Affiliations
1 School of Oceanography, Jadavpur University, Calcutta - 700 032, IN

Abstract

Linear mounds of sands, spread over 400 km² in the Balasore-Contai floodplain and aligned parallel as well as close to the shoreline are not past strandline markers. It is suggested that these are compound products of fluviatile deposits capped by aeolian accumulations during late Holocene, albeit undated, arid intervals. The mounds were stabilished by soil and vegetation cover and are presently under anthropogenic attack.

Keywords

Oceanography, Quaternary, Floodplain, W. Bengal, Orissa.

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