MAJOR NEOTECTONIC EVENTS DURING THE QUATERNARY IN KRISHNA-GODAVARI BASIN

The Krishna-Godavari Basin is an onland petroliferous basin under active stage of exploration. Situated on the East Coast of the Indian subcontinent, the basin developed as a result of continental rifting of the Gondwanaland and a subsequent drift phase during Mid-Cretaceous. It has thus a long history of basin development stretching from Jurassic to Quaternary. The Quaternary events of the basins are best reflected by surface landforms. The basin can be divided into three broad geomorphic units: Fluvio-deltaic complex of continental environment, Beach-Ridge complex of fluvio-marine environment and Bay-Estuary Lagoon Complex of shallow marine environment. Lineament studies indicate three dominant trends ENE-WSW, NW-SE and NE-SW. The dominant NE-SW trend is related to the Eastern Ghat orogeny, along which rifting and separation of Antarctica took place in Mid-Cretaceous. Some of the major ENE-WSW and NE-SW trends are correlatable to subsurface faults which divide the basin into horsts and grabens, indicating their active role in the basin development. On the basis of interpretation of satellite images and data obtained from few shallow bore holes, five Quaternary events reflected as palaeostrand-line shifts have been recognized. These indicate rapid growth of delta, the progradation rate being roughly 3.5 kilometre per thousand years after 10,000 +/- 155 yr B. P.