New Paleomagnetic and Chronological Constraints on the Late Triassic Position of the Eastern Qiangtang Terrane: Implications for the Closure of the Paleo‐Jinshajiang Ocean
Liang Yu, Maodu Yan, Mathew Domeier, Chong Guan, Miaomiao Shen, Qiang Fu, Wanlong Xu, Zunbo Xu, Zhichao Niu, Liye Yang, Rendeng Shi, Weilin Zhang, Jinbo Zan, Dawen Zhang, Bingshuai Li
Abstract
Abstract The tectonic evolution of the Paleo‐Jinshajiang Ocean, and in particular the time of its closure, is debated. Here we present new constraints on the evolution of this region from an integrated paleomagnetic and geochronologic study of the Late Triassic Batang Group volcanic rocks in Qamdo, Eastern Qiangtang Terrane (EQT). Two zircon U‐Pb ages indicate that the volcanic rocks erupted at ∼227–222 Ma. New paleomagnetic results yield a robust Late Triassic paleopole of 57.6°N, 176.4°E ( A 95 = 7.8°), corresponding to a paleolatitude of 32.5 ± 7.8°N for the study area. Integrated with other lines of paleomagnetic and geological evidence, we show that the northward drift of the EQT placed it at the same paleolatitude as the Tarim Block by ∼227–222 Ma, which suggests that the Paleo‐Jinshajiang Ocean in the Qamdo region closed before that time, and likely around ∼230 Ma.