HR: 1340h
AN: GP43C-1489 [Abstracts]
TI: Timing and distribution of tectonic rotations in the northeastern Tibetan plateau
AU: Dai, S
EM: daisher@lzu.edu.cn
AF: Key Laboratory of Western China's
Environmental Systems, Ministry of Education of China & College of Resources and Environment, Lanzhou
University, Lanzhou, Gan 730000, China
AU: Fang, X
EM: fangxm@itpcas.ac.cn
AF: Institute of Tibetan Plateau Research, Chinese Academy of Science, P.O. Box 2871,
Beijing, 100085, China
AU: * Dupont-Nivet, G
EM: gdn@geo.uu.nl
AF: Paleomagnetism Laboratory
"Fort Hoofddijk", Faculty
of Geosciences, Utrecht University, Budapeslaan 17, Utrecht, 3584 CD, Netherlands
AU: Krijgsman, W
EM: krijgsma@geo.uu.nl
AF: Paleomagnetism Laboratory
"Fort Hoofddijk", Faculty
of Geosciences, Utrecht University, Budapeslaan 17, Utrecht, 3584 CD, Netherlands
AU: Erens, V
EM: v_erens@email.com
AF: Paleomagnetism Laboratory
"Fort Hoofddijk", Faculty
of Geosciences, Utrecht University, Budapeslaan 17, Utrecht, 3584 CD, Netherlands
AU: Reitsma, M
EM: M.J.Reitsma@students.uu.nl
AF: Paleomagnetism Laboratory
"Fort Hoofddijk", Faculty
of Geosciences, Utrecht University, Budapeslaan 17, Utrecht, 3584 CD, Netherlands
AU: Langereis, C
EM: langer@geo.uu.nl
AF: Paleomagnetism Laboratory
"Fort Hoofddijk", Faculty
of Geosciences, Utrecht University, Budapeslaan 17, Utrecht, 3584 CD, Netherlands
AB:
We report paleomagnetic data from the northeastern margin of the Tibetan plateau to understand the timing and
distribution of deformation (i.e. vertical-axis rotations) during the Indo-Asia collision. Paleomagnetic results
throughout the Xining Basin Paleogene and Neogene strata, recently dated using magnetostratigraphy between
52 and 17 Ma, show that some 25° clockwise rotation with respect to the stable Eurasian continent,
occurred at ca. 41 Ma. In view of the regional compilation of existing paleomagnetic from the northeastern Tibetan
plateau, these results suggest that this region experienced two phases of clockwise rotation distinct in time and
place. (1) During a mid-Eocene phase, clockwise rotations took place in the regional Paleocene-Miocene basin
system including rotation in the Xining Basin at ca. 41 Ma, thus establishing the existence of widespread
deformation at this time. (2) During a mid-Miocene phase, (within 17 to 11 Ma), clockwise rotations are restricted
to the Mio-Quaternary basin system, implying that the Laji Shan thrust belt, separating the two basin systems,
was active during this time interval. These results are consistent with low temperature thermochronology
constraints on tectonics of the Laji Shan indicating exhumation starting at ca. 15 Ma (See Dupont-Nivet et al., this
meeting, Session T20).
UR: http://www.geo.uu.nl/~forth/people/Guillaume
DE: 1140 Thermochronology
DE: 1500 GEOMAGNETISM AND PALEOMAGNETISM
DE: 1525 Paleomagnetism applied to tectonics: regional, global
DE: 1535 Reversals: process, timescale, magnetostratigraphy
DE: 8100 TECTONOPHYSICS
SC: Geomagnetism and Paleomagnetism [GP]
MN: 2007 Fall Meeting