Late Paleozoic granitoids from central Qiangtang, northern Tibetan plateau: A record of Paleo-Tethys Ocean subduction

• Published in: Journal of Asian earth sciences Vol. 167; pp. 139 - 151
• Main Authors: Zhai, Qing-guo, Wang, Jun, Hu, Pei-yuan, Lee, Hao-yang, Tang, Yue, Wang, Hai-tao, Tang, Suo-han, Chung, Sun-lin
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.11.2018
• Subjects: Granitoid; Late Paleozoic; Paleo-Tethys Ocean; Qiangtang; Subduction; Tibet; Zircon U-Pb age; Paleo-Tethys Ocean; Late Paleozoic; Granitoid; Zircon U-Pb age; Tibet; Qiangtang; Subduction
• ISSN: 1367-9120; 1878-5786
• DOI: 10.1016/j.jseaes.2017.07.030

[Display omitted] •There are Late Paleozoic granitic plutons along the Longmu Co-Shuanghu suture.•These plutons emplaced between 346Ma and 364Ma and formed in a subduction related tectonic setting.•Subduction of the Paleo-Tethys Ocean began in the Late Devonian and lasted till the Triassic. The Longmu Co-Shuanghu suture zone in central Qiangtang, northern Tibetan plateau, is a segment of the main suture zone of the Paleo-Tethys Ocean. Numerous studies have focused on ophiolite and high-pressure metamorphic rocks from this suture zone, whereas the associated subduction-related magmatic rocks have received little attention. In this study, we present new data for the Late Paleozoic granitoids from the Gangma Co, Guoganjianian and Chasum areas along the Longmu Co-Shuanghu suture zone. Zircon U-Pb dating indicates that these granitic rocks were emplaced between 364Ma and 346Ma (Late Devonian-Early Carboniferous). Three granitic plutons exhibit different geochemical compositions, but show uniform Sr-Nd and zircon Hf isotopic features with positive ƐNd(T) and zircon ƐHf(T) values. Furthermore, these rocks were all formed in a volcanic arc setting associated with an oceanic subduction zone. Together with data from coeval volcanic rocks, we suggest that the Late Paleozoic magmatic rocks were formed as a result of northward subduction of the Paleo-Tethys Ocean. Subduction of the Paleo-Tethys Ocean probably commenced in the Late Devonian, continued throughout the Late Paleozoic, and ended in the Triassic.