Volcanism in the Younger Dharwar Rocks Near Medur Dharwar District, Karnataka

Abstract

Andesite lavas are associated with pyroclastics and a few sheet-like porphyritic flows. The volcanism is considered to have been of mixed eruptions indicating sufficient fluidity and low gas content. The andesitic lavas are characterised by well developed pillow structure. They are interlayered with pyritiferous and carbonaceous argillites indicating volcanic eruption under submarine condition.

The lavas occupy the central part of a major refolded antiformal anticline plunging to the west. They have undergone metamorphism only up to the green-schist facies of regional metamorphism. Carbonatisation of lavas is a common feature, particularly in andesite.