Along the N slopes of the Ladakh Range a linear belt of calc-alkaline volcanics designated as 'Khardung Volcanics' are exposed in the Shyok Valley. These volcanics comprise rhyodacites, dacites, andesites with associated ignimbrites, and pyroclastics. The tectonic zones present in this region from S to N are 1) Sangeluma Group (=Indus flysch) of Cretaceous-Eocene age comprising flysch and ophiolites, thrust over, 2) the Indus Group (=Indus Molasse) of molassic sediments of Mio-Pliocene age uncomformably overlying, 3) the batholithic Ladakh Granitoid Complex of Tertiary age, intruding into 4) the 'Khardung volcanics' of Upper Cretaceous to Lower Tertiary age, comprising a suite of calc-alkaline volcanics and overlain along a fault plane by 5) the Mid- to Late Cretaceous flyschoid Hundiri Formation underlain by 6) early Cretaceous ophiolitic Biagdang Formation. The Khardung Volcanics and the Hundiri Formation are repeated N of Shyok Valley by an antiformal fold where the Khardung Volcanics are thrust along a thrust plane by 7) late Palaeozoic Aranu Formation and 8) Tertiary Karakorum Granitoid Complex. The Khardung Volcanics occur in strike continuity of Trans-Himalayan acid to intermediate volcanics of S Tibet in the E and acid-intermediate lavas of Hazara, Swat and Dir in the W. The Khardung Volcanics are now considered to represent a phase of Island arc volcanism generated during the subduction of the Indian plate along the Indus Suture Zone in Upper Cretaceous-Lower Tertiary times.-Authors Geol Survey of India, Lucknow, India.
