GIANT MASS TRANSPORT DEPOSIT ON THE WESTERN INDIAN CONTINENTAL MARGIN: THE NATARAJA SLIDE

Two-dimensional, depth-migrated seismic reflection profiles and seafloor bathymetry have been used to describe a giant mass-transport complex deposit off the west coast of India. This giant deposit runs from the Gujurat-Saurashtra to the Laxmi Basin and is over 330 km long and a maximum of 190 km wide. Its run out basal gradient is 1.2°. We name this giant mass wasting deposit the Nataraja Submarine Slide. This slide covers 5±0.2 x 10⁴ km² and represent a volume of 19±4 x 10³ km³, exceeding in volume any previously described mass-transport complex on the Earth’s surface or in the rock record. Mass balance estimates between the scar and the deposited volume are in agreement. Seismic facies analysis allows the internal structure of the mass-transport complex to be described including up-dip extension and downslope contractional deformation. This slide has been able to circumvent massive seamounts, thus highlighting the capacity of the flow and its potential energy during emplacement in a funnel between the slope of the Western Indian passive margin and the Laxmi Ridge. Stratigraphically, the emplacement of the Nataraja Slide occurred within the late Miocene and its toe region is embedded within turbidite sequences of the Indus Fan. The margin architecture at the head of this slide is associated with a deep-seated fold and thrust belt that may have played a role in the origin of the slide during gravitational stacking of a complex tectonic wedge.