New paleomagnetic results from the Xigaze fore-arc basin: Tectonic implications for the collision of India and Asia
Abstract
Paleolatitude of the southernmost Eurasia is of prime importance for understanding the collision of India and Eurasia. We conducted paleomagnetic investigation in Cuojiangding Section along the northern side of the Yarlung Zangbo Suture Zone in southern Tibet, which belongs to the Xigaze forearc basin. There Cuojiangding Section contains Late Cretaceous-Eocene strata overlying the Xigaze Group in the Xigaze forearc basin. It consists from bottom to top of the Padana (Late Cretaceous), Qubeiya (Late Cretaceous), Quxia (Paleocene) and Jialazi (Paleocene-Eocene) formations. The main lithological characters include sandstone, conglomerate, limestone and multi-layer volcanics from coeval sediments. The age of section was well limited by previous work of fossils. Especially recently, the depositional age of QuXia Formation is well constrained at∼55 Ma by the tuff dating. Our preliminary results suggest that a high temperature, characteristic remanent magnetization (ChRM) was isolated from totally 29 sites. All the ChRM directions are significantly different from the present-day geomagnetic field. The site mean directions of sediments and tuffs pass the conglomerate test and fold test. Paleomagentic results from the Quxia formation yield a paleolatitude of approximate 23°N for the southernmost margin of Eurasia at ~55 Ma. In addition, nearly all the Quxia formation specimens indicated a reversed polarity, which coincide with the Geomagnetic Polarity timescale at 55 Ma. Our data support India-Asia continental collision to occur at least in the late Paleocene.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2011
- Bibcode:
- 2011AGUFM.T51D2360M
- Keywords:
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- 1525 GEOMAGNETISM AND PALEOMAGNETISM / Paleomagnetism applied to tectonics: regional;
- global;
- 8102 TECTONOPHYSICS / Continental contractional orogenic belts and inversion tectonics;
- 9320 GEOGRAPHIC LOCATION / Asia;
- 9604 INFORMATION RELATED TO GEOLOGIC TIME / Cenozoic