Informatics Publishing Limited

Venkateshwarlu Mamilla , J. Mallikharjuna Rao , K. P. Sarma , J. J. Laskar , Nivarani Devi

Abstract

Palaeomagnetic and petrological results from a volcanic tuff in the least studied Purana basin of the Shillong Plateau, NE India are reported here for the first time. Haematite is the dominant remanent carrier mineral identified by the rock magnetic, optical and palaeomagnetic studies. Intensity decay curves during progressive thermal demagnetization attest its characteristic nature. Characteristic Remanent Magnetization (ChRM) directions reveal that the declinations are in southern hemisphere with negative, shallow inclinations (N=5, Dm=182°, Im= -2°, α95=8.37). The signatures of the Kerguelen hotspot-related volcanism allow us to suggest that the Shillong Tuff rocks may be considered originated from an interaction between the Kerguelen hotspot and the lithosphere of the northeastern margin of Greater India during early Cretaceous (Royer&Coffin 1992).

Keywords

Shillong Plateau, Volcanic Tuff, Palaeomagnetism, NE India

Full Text