The Deccan Trap Basalt Flows of the Bor Ghat Section of Central Railway

Abstract

On the basis of their form the flows are divided into four Groups: (1) thick extensive flows of compact basalt, (2) tabular flows of amygdaloidal basalt, (3) thin irregular flows of amygdaloidal basalt; and (4) thick irregular flows of amygdaloidal basalt. Flows of Groups 1 and 2 appear to be the products of fissure type of volcanicity. The irregular form and small size of flows of Groups 3 and 4 suggest that they were formed by eruption of viscous lava in small quantities. The small basaltic intrusions found associated with these flows probably represent the cracks through which magma rose.

Two entirely different types of volcanicity dominated at different times in this area. Eruptions producing flows of Groups 3 and 4 were prevalent in the early period, while fissure type of activity producing flows of Groups 1 and 2 took place in the later period. The flows appear to have come in quick succession without any intertrappean interval.