Insights into the P–T evolution path of Tso Morari eclogites of the north-western Himalayas: Constraints on the geodynamic evolution of the region Preeti Singh, Ashima Saikia∗, Naresh Chandra Pant and Pramod Kumar Verma∗∗ Department of Geology, University of Delhi, Delhi 110 007, India. ∗Corresponding author. e-mail:
[email protected] The present study is on the Ultra High Pressure Metamorphic rocks of the Tso Morari Crystalline Com- plex of the northwestern Himalayas. Five different mineral associations representative of five stages of P–T (pressure–temperature) evolution of these rocks have been established based on metamorphic tex- tures and mineral chemistry. The pre-UHP metamorphic association 1 of Na-Ca-amphibole + epidote ± paragonite ± rutile ± magnetite with T–P of ∼ 500◦C and 10 kbar. This is followed by UHP metamor- phic regime marked by association 2 and association 3. Association 2 (Fe>Mg>Ca-garnet + omphacite + coesite + phengite + rutile ± ilmenite) marks the peak metamorphic conditions of atleast 33 kbar and ∼ 750◦C. Association 3 (Fe>Mg>Ca-garnet + Na-Ca amphibole + phengite ± paragonite ± calcite ± ilmenite ± titanite) yields a P–T condition of ∼28 kbar and 700◦C. The post-UHP metamorphic regime is defined by associations 4 and 5. Association 4 (Fe>Ca>Mg-garnet + Ca-amphibole + plagioclase (An05) + biotite + epidote ± phengite yields a P–T estimate of ∼14 kbar and 800◦C) and association 5 (Chlorite + plagioclase (An05) + quartz + phengite + Ca-amphibole ± epidote ± biotite ± rutile ± titanite ± ilmenite) yields a P–T value of ∼7 kbar and 350◦C. 1. Introduction (UHPM) and their subsequent exhumation and preservation at surface conditions (e.g., UHPM Reported occurrence of coesite, the high pressure rocks from the Kokchetav massif, Kazakhstan; polymorph of quartz as inclusions in the garnets Dabie-Shan, China and western Gneiss Region, of eclogitic rocks from Norway and the Alps region Norway, Dora Maria Massif, W.