GUO Rui-qing, CUI Tao, LIU Gui-ping, GONG Xiang-kuan, SONG Zhi-hao

( Xinjiang Key Laboratory of Geodynamic Processes and Metallogenic Prognosis of the Central Asian Orogenic Belt, College of Geology and Mining Engineering, Xinjiang University, Urumqi 830046, China)

Abstract: Whether the northern margin of Tarim plate was an active continental margin in Paleozoic is of great importance for understanding the subduction mode of the South Tianshan ocean and the geological evolution of the northern margin of Tarim plate. In this paper, 69 grains of detrital zircons collected from the Wusitenggaole river in the northern Quruqtagh area have been examined by using cathodoluminescent imaging method and dated by using LA-ICP-MS U-Pb dating method. The obtained data of 50 groups of U-Pb effective ages show that: (1) The provenances of river sediments are mainly concentrated into 379－466 Ma, 651－651 Ma, and 817－2122 Ma aged rocks in the northern Quruqtagh area. (2) The effective U-Pb ages of detrital zircons have revealed there were at least 3 tectonic thermal events. Especially, ages ranging from 379 to 466 Ma of detrital zircons indicate that there were large scale magmatisms in the Quruqtagh area in the middle Paleozoic. It is found by comparative study that those Middle Paleozoic magmatic events could be related to the southward subduction of the South Tianshan ocean and the active continental margin of the northern margin of the Tarim plate. The Neoproterozoic magmatism may be a record of the Rodinia supercontinent cracking event. The existence of Paleoproterozoic metamorphic zircons may be related to tectonic events of the Colombia supercontinent.

Keywords: stream sediments; detrital zircon U-Pb dating; provenance analysis; Quruqtagh; northern margin of Tarim

ACTA MINERALOGICA SINICA Vol. 40, No.6, 2020, page 747-757