Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Wallis, S. Articles by Hyodo, H. Search for Related Content GeoRef GeoRef Citation

Cenozoic and Mesozoic metamorphism in the Longmenshan orogen: Implications for geodynamic models of eastern Tibet

¹ Department of Earth and Planetary Sciences, Graduate School of Environmental Studies, Nagoya University, Nagoya 464-8602, Japan
² Research Institute of Natural Sciences, Okayama University of Science, Okayama 700-0005, Japan
³ Department of Earth and Planetary Sciences, Graduate School of Environmental Studies, Nagoya University, Nagoya 464-8602, Japan
⁴ Department of Earth Sciences, Faculty of Education, Okayama University, Okayama 700-8530, Japan
⁵ Department of Earth and Planetary Systems Science, Graduate School of Science, Hiroshima University, Hiroshima 739-8526, Japan
⁶ Nagoya University Center for Chronological Research, Nagoya University, Nagoya 464-8602, Japan
⁷ Research Institute of Natural Sciences, Okayama University of Science, Okayama 700-0005, Japan

New zircon U-Pb and mica ⁴⁰Ar/³⁹Ar dating combined with structural studies in the Longmenshan orogen confirm that most of the upper crustal deformation in the eastern margin of Tibet is Mesozoic. However, at lower structural levels, apatite U-Pb and monazite electron microprobe dating reveals a previously unknown domain of Cenozoic (ca. 65 Ma) Barrovian-type metamorphism and deformation. This discovery shows that the crust in the eastern margin of Tibet was already a substantial thickness around the time of the India-Asia collision. Associated deformation has a N-S-oriented stretching lineation, implying that deformation was not driven by topographic gradients in the Tibetan Plateau. The observed moderate amounts of distributed postmetamorphic E-W shortening can probably explain the present thickness of the continental crust in the area. These results do not support models of crustal thickening caused by solid-state lateral flow of midcrustal metamorphic rocks.

Key Words: Tibetan Plateau • radiometric dating • metamorphism • Cenozoic tectonics

This article has been cited by other articles:

				P. Kapp, P. G. DeCelles, G. E. Gehrels, M. Heizler, and L. Ding Geological records of the Lhasa-Qiangtang and Indo-Asian collisions in the Nima area of central Tibet Geological Society of America Bulletin, July 1, 2007; 119(7-8): 917 - 933. [Abstract] [Full Text] [PDF]

				D. Jia, G. Wei, Z. Chen, B. Li, Q. Zeng, and G. Yang Longmen Shan fold-thrust belt and its relation to the western Sichuan Basin in central China: New insights from hydrocarbon exploration AAPG Bulletin, September 1, 2006; 90(9): 1425 - 1447. [Abstract] [Full Text] [PDF]

				P. Kapp, A. Yin, T. M. Harrison, and L. Ding Cretaceous-Tertiary shortening, basin development, and volcanism in central Tibet Geological Society of America Bulletin, July 1, 2005; 117(7-8): 865 - 878. [Abstract] [Full Text] [PDF]

				Q.-R. Meng, E. Wang, and J.-M. Hu Mesozoic sedimentary evolution of the northwest Sichuan basin: Implication for continued clockwise rotation of the South China block Geological Society of America Bulletin, March 1, 2005; 117(3-4): 396 - 410. [Abstract] [Full Text] [PDF]