Early Cretaceous to Eocene magmatic records in Ladakh arc: Constraints from U–Pb ages of Deosai volcanics, northern Pakistan. (12th January 2020) - Jadoon, Umair Khan
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.