LITHOSPHERIC STRUCTURE BENEATH LAXMI RIDGE AND LATE CRETACEOUS GEODYNAMIC EVENTS

The geophysically unusual Laxmi Ridge (eastern basin, Arabian Sea) is associated with a prominent elongated negative gravity anomaly. A seis mically and geodynamically constrained detailed 2D gravity modeling su ggests an 11-km-thick normal oceanic crust and an asthenospheric upwar p to a depth of 35 km. We attribute the apparent thickening of the cru st to a possible emplacement of an anomalous subcrustal low-density la yer between 11 and 19 km depth. We hypothesize that a K-T boundary bol ide impact near the Bombay offshore led to several geological events, including eruption of Deccan flood basalts. The spreading Carlsberg Ri dge in the Indian Ocean and rifting associated with Deccan volcanism g enerated the compressive regime, which perhaps originated the Laxmi Ri dge.