The Kaladgi Basin on the northern edge of the Dharwar craton has characters diverse from the other epicratonic Purana basins of Peninsular India. Sedimentological studies in the basin have established the presence of three cycles of flooding separated by an event of intra-basinal deformation accompaniedby low grade incipient metamorphism. The overall structural configuration of the basin indicates its development by supracrustal extension accompanied by shearing in a trans-tensional regime during the Mesoproterozoic. This was followed by sagging that yielded Neoproterozoic sedimentation in a successornested basin. ⁴⁰Ar / ³⁸Ar dating

of an intrusive mafic dyke along the axial plane of a fold has yielded a plateau age of 1154±4Ma. This helps constraint the age of the various events during the evolution of this basin.

We describe the distribution and characters of a megaporphyritic basalt flow field that was arguably the earliest described ‘giant phenocryst basalt’ (GPB) from the Deccan Volcanic Province (DVP). It is a marker horizon exposed in a > 30,000 $km^{2}$ area below the Mahabaleshwar Formation in the western DVP. Its presence, distribution and stratigraphic importance as a regional marker horizon are enumerated. Available geochronological and paleomagnetic data suggest that the stratigraphic position of the Rajgad GPB coincides with polarity reversal in Chron 29 recorded from the basaltic lava sequence of the Western DVP.

The crust is a vesicular layer that caps the compact core of sheet lava flows. We describe for the first time, a crust composed of multiple layers (each distinguished by a chilled glassy rind) from the Diveghat Formation in the western Deccan Volcanic Province. The multiple layers of crust developed over a single compact core of a single sheet lava flow, are shown to have been sequentially deformed in multiple phases. This is interpreted to have resulted from the endogenous emplacement of lava in successive pulses (rather than as a continuous stream) during the extrusion of the sheet lava flow. This model has several implications on the mechanism of emplacement of sheet flows in continental flood basalt provinces.