Paleomagnetic Constraints on the India–Asia Collision and the Size of Greater India
Weiwei Bian, Tianshui Yang, Wenxiao Peng, Suo Wang, Feng Gao, Shihong Zhang, Huaichun Wu, Haiyan Li, Liwan Cao, Tian Jiang, Huapei Wang
Abstract
Abstract The timing and location India–Asia collision is crucial to understanding the evolution of the Himalayan–Tibetan orogen and global climate change; however, estimates of the timing of the India–Asia collision and the size of Greater India remain highly controversial. We report here the first reliable early Eocene paleomagnetic results from the Zhepure Formation limestone in the Tethyan Himalaya (TH). Both positive fold and reversal tests indicate a primary origin. The tilt‐corrected site‐mean direction is Ds = 332.6°, Is = 20.1°, ks = 90.9, α 95 = 2.8° ( N = 30). The site‐mean inclination increased from 20.1° to 27.5° after inclination shallowing correction, yielding a paleopole at 61.2°N, 337.3°E, A 95 = 2.6° and a corresponding paleolatitude of 15.2° ± 2.6°N for the reference point (29.5°N, 91.0°E). Our new paleomagnetic results, together with the reliable Cretaceous to Paleogene paleomagnetic results from the TH, Lhasa terrane and Indian craton, suggest that there was ∼900–1,140 km north‐south crustal shortening occurred between the TH and the Indian craton, and that India collided with Asia at no later than ∼51–49.5 Ma.