Giant fossil mass wasting off the coast of West India: The Nataraja submarine slide

• Published in: Earth and planetary science letters 2015-12, Vol.432, p.265-272
• Main Authors: Calvès, Gérôme, Huuse, Mads, Clift, Peter D., Brusset, Stéphane
• Format: Article
• Language: English
• Subjects: Arabian Sea; Architecture; Coastal environments; Deposits; Earth Sciences; Fossils; India; mass wasting; Sciences of the Universe; Seamounts; Sedimentation; seismic reflection; Slopes; Stratigraphy; West India margin
• ISSN: 0012-821X; 1385-013X
• DOI: 10.1016/j.epsl.2015.10.022

We use two-dimensional pre-stack depth migrated seismic reflection profiles and seafloor bathymetry to describe the continental margin structure and a massive mass-transport deposit off the west coast of India. This giant slide runs from the Gujurat–Saurashtra margin to the Laxmi Basin. It is over 330 km long, a maximum of 190 km wide and its run-out basal gradient is 1.2°. We name this giant mass wasting deposit the Nataraja Submarine Slide. This slide covers 49±16×103 km2 and represents a volume of 19×103±4×103 km3, making it the second by volume of any passive margin landslide/mass-transport deposit. Seismic facies analysis allows the internal structure of the mass-transport deposit to be described as far as the toe. 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 predates the main pulse of sedimentation during the late Miocene–Recent associated with the Indus Fan but follows rapid sedimentation across S and SE Asia during the Early–Middle Miocene. The margin architecture at the head of this slide is associated with a gravity-controlled fold and thrust belt that may have caused slope steepening and triggering of the slide. •First description of a giant slide offshore western India, named Nataraja Slide.•The Nataraja Slide is late Miocene in age.•Role of mass wasting on margin sedimentary budget.