Multi-tiered, disrupted crust of a sheet lava flow from the Diveghat Formation of Deccan Traps: Implications on emplacement mechanisms

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.