Early Cretaceous to Eocene magmatic records in Ladakh arc: Constraints from U–Pb ages of Deosai volcanics, northern Pakistan

Abstract

This research provides a detailed U–Pb geochronological record of Deosai volcanics in the western Himalaya. The volcanics comprise basalt, andesite, dacite, and rhyolite and are part of the Kohistan–Ladakh arc, exposed east of the Nanga Parbat–Haramosh Massif. Based on the U–Pb ages, this volcanic suite is classified into three chronostratigraphic units: (a) Chota Pani volcanics, (b) Shatung Nala volcanics, and (c) Bara Pani volcanics, with ages ranging between 123–115, 86–63, and 48–46 Ma, respectively. This study suggests that the Chota Pani volcanics are arc‐related, as their ages coincide well with the timing of initiation of the Kohistan–Ladakh arc. The Shatung Nala volcanics may have formed as a result of a collision between Kohistan–Ladakh arc and Karakoram Block (Eurasian Plate). Moreover, the U–Pb cluster age of Bara Pani volcanics coincides with the initial collision time between Indian and Eurasian plates in the western Himalaya, which strongly suggests its emplacement associated with the continental–continental collision. In addition, the dated granitic samples, yielding 120.9 ± 4.5, 80.2 ± 1.4, 50.42 ± 0.55, and 45.24 ± 0.64 Ma ages, provide further support that the emplacement of Deosai volcanic rocks took place as a consequence of closure of the northern and southern sutures, respectively.

Petrological and geochemical characterization of the arc-related Suru–Thasgam ophiolitic slice along the Indus Suture Zone, Ladakh Himalaya

“…Well-studied Mesozoic Neo-Tethyan ophiolitic sequences are exposed along the northern Indian plate margin, that is, Indus Yarlung Tsangbo Suture (IYTS; Hebert et al 2012;Liu et al 2016;Bhat et al 2017aBhat et al , 2019aKingson et al 2017;Xiong et al 2017;Buckman et al 2018;Jadoon et al 2020). However, due to extreme high altitude (average height 3000 m) and poor accessibility to the Ladakh terrain, especially Kargil region of western Ladakh, limited research work has been carried out on the western Ladakh ophiolites, particularly on Suru-Thasgam dismembered ophiolitic slice, thrust over the Dras arc complex.…”