Tectonics and sedimentation in the passive margin, trench, fore-arc and backarc areas of the indus suture zone in ladakh and karakorum: A review

Abstract

Three distinct turbidite basins are recognised in the Indus-Tsangpo Suture Zone of NW Indian Himalayan region. The broad facies organisation of these turbidite basins suggests that they are attributable to passive and active margins of the Neo-Tethyan oceanic realm. The syn-post-rift deep marine, fine-grained Lamayuru Formation, dated from Triassic to Eocene, represents an accreted oceanic basin of the Indian passive margin. The syn-tectogenic trench and trench-slope volcanogenic turbidites of the Nindam Formation represent an accretionary fore-arc basin of Late Cretaceous-Eocene age. The Nindam Formation is correlated with the Congdu trench sediments of southern Tibet. The syn-orogenic composite turbidites of the Indus Formation represent a residual fore-arc basin that lately evolved towards composite type as a result of the changing geometry of provenance terrains. The Middle-Late Cretaceous to Eocene Indus Formation is correlated with the Xigaze forearc basin of southern Tibet. Adjacent to the Indus-Tsangpo Suture in the northern part of Indian Himalaya, an important tectonised zone is revealed by the Late Palaeozoic to Miocene rocks of Shyok Suture. It is a complex association of turbidites and ophiolitic melanges with volcanics, calc-alkaline magmatism and molasse-type sedimentary sequences. This Suture Zone has had a complex accretionary history along with the Karakorum terrane. © Masson, Paris, 1997.