TY  - JOUR
A1  - Huang, Wentao
A1  - van Hinsbergen, Douwe J. J.
A1  - Dekkers, Mark J.
A1  - Garzanti, Eduardo
A1  - Dupont-Nivet, Guillaume
A1  - Lippert, Peter C.
A1  - Li, Xiaochun
A1  - Maffione, Marco
A1  - Langereis, Cor G.
A1  - Hu, Xiumian
A1  - Guo, Zhaojie
A1  - Kapp, Paul
T1  - Paleolatitudes of the Tibetan Himalaya from primary and secondary magnetizations of Jurassic to Lower Cretaceous sedimentary rocks
T2  - Geochemistry, geophysics, geosystems
N2  - The Tibetan Himalaya represents the northernmost continental unit of the Indian plate that collided with Asia in the Cenozoic. Paleomagnetic studies on the Tibetan Himalaya can help constrain the dimension and paleogeography of "Greater India,' the Indian plate lithosphere that subducted and underthrusted below Asia after initial collision. Here we present a paleomagnetic investigation of a Jurassic (limestones) and Lower Cretaceous (volcaniclastic sandstones) section of the Tibetan Himalaya. The limestones yielded positive fold test, showing a prefolding origin of the isolated remanent magnetizations. Detailed paleomagnetic analyses, rock magnetic tests, end-member modeling of acquisition curves of isothermal remanent magnetization, and petrographic investigation reveal that the magnetic carrier of the Jurassic limestones is authigenic magnetite, whereas the dominant magnetic carrier of the Lower Cretaceous volcaniclastic sandstones is detrital magnetite. Our observations lead us to conclude that the Jurassic limestones record a prefolding remagnetization, whereas the Lower Cretaceous volcaniclastic sandstones retain a primary remanence. The volcaniclastic sandstones yield an Early Cretaceous paleolatitude of 55.5 degrees S [52.5 degrees S, 58.6 degrees S] for the Tibetan Himalaya, suggesting it was part of the Indian continent at that time. The size of "Greater India' during Jurassic time cannot be estimated from these limestones. Instead, a paleolatitude of the Tibetan Himalaya of 23.8 degrees S [21.8 degrees S, 26.1 degrees S] during the remagnetization process is suggested. It is likely that the remagnetization, caused by the oxidation of early diagenetic pyrite to magnetite, was induced during 103-83 or 77-67 Ma. The inferred paleolatitudes at these two time intervals imply very different tectonic consequences for the Tibetan Himalaya.
Y1  - 2015
UR  - https://publishup.uni-potsdam.de/frontdoor/index/index/docId/39379
SN  - 1525-2027
VL  - 16
IS  - 1
SP  - 77
EP  - 100
PB  - American Geophysical Union
CY  - Washington
ER  -