Paleornagnetic and geochronological constraints on the post-collisional northward convergence of the southwest Tian Shan, NW China

doi:10.1016/j.tecto.2005.08.018

	Paleornagnetic and geochronological constraints on the post-collisional northward convergence of the southwest Tian Shan, NW China
	Huang, BC ; Piper, JDA ; Wang, YC ; He, HY ; Zhu, RX
刊名	TECTONOPHYSICS
	2005-11-16
卷号	409 期号:1-4 页码:107-124
关键词	Tian Shan Tuoyun Basin China Palcomagnetism Ar-40/ar-39 Dating Palcogene Basalt Flows Red Beds Indo-asian Tectonics
ISSN号	0040-1951
DOI	10.1016/j.tecto.2005.08.018
文献子类	Article
英文摘要	A combined paleomagnetic and geochronological Study is reported of Paleogene basalt lavas and an intercalated red bed succession, comprising a minimum of 14 basalt flows and 10 red bed horizons in the Tuoyun Basin of the southwest Tian Shan Range, China. Two basalt matrix samples yield Ar-40/Ar-39 isochron ages of 58.5 +/- 1.3 Ma (2 sigma, MSWD = 0.9) and 60.4 +/- 1.3 Ma (2 sigma, MSWD = 1.7). These compare well with a previously published K-Ar dilution age of 61.7 +/- 2.3 Ma for comparable Paleogene basalts and confirm that the younger Pulse of magmatism in this basin is represented by both intrusive and extrusive activity. Demagnetization and component analysis identify a stable characteristic remanence (ChRM) with predominantly reversed polarity following removal of secondary remanence by peak demagnetization steps below 250-350 degrees C or 5 mT. Rock magnetic analysis identifies pseudo-single domain magnetite or titanomagnetite as carriers. The stable ChRM passes a fold test; it was probably acquired at the time of lava emplacement. Results from the bulk or the collection imply that paleomagnetic data from the upper and lower (similar to 115 Ma) basalt series in the Tuoyun Basin are not distinguishable at the 95% significance level and indicate that this tectonic domain remained essentially stationary with respect to the Earth's spin axis for similar to 50 Ma prior to onset of the India/Asia collision in early Eocene times. It is therefore probable that no paleomagnetically detectable crustal shortening Occurred in the southwest Tian Shan prior to collision. Paleomagnetic data sets from the Tuoyun Basin also show that little or no paleolatitude difference is present between the Tian Shan and the reference latitude of Eurasia at similar to 60 Ma. This supports previous evidence suggesting that central Asian blocks in the vicinity of the Tian Shan are unlikely to have experienced appreciable northward convergence relative to Eurasia since onset of the India/Asia collision and initiation of the Himalaya. (c) 2005 Elsevier B.V.. All rights reserved.
WOS关键词	INDIA-EURASIA COLLISION ; CENTRAL-ASIA ; TIEN-SHAN ; TARIM BASIN ; TECTONIC EVOLUTION ; PALEOMAGNETIC DATA ; GEOMAGNETIC-FIELD ; TIBET PLATEAU ; POLAR WANDER ; RED BEDS
WOS研究方向	Geochemistry & Geophysics
语种	英语
出版者	ELSEVIER SCIENCE BV
WOS记录号	WOS:000233674000007
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/65388]
专题	中国科学院地质与地球物理研究所
通讯作者	Huang, BC
作者单位	1.Chinese Acad Sci, Inst Geol & Geophys, Paleomagnetism & Geochronol Lab, SKL LE, Beijing 100029, Peoples R China 2.Univ Liverpool, Dept Earth & Ocean Sci, Geomagnetism Lab, Liverpool L69 7ZE, Merseyside, England
推荐引用方式 GB/T 7714	Huang, BC,Piper, JDA,Wang, YC,et al. Paleornagnetic and geochronological constraints on the post-collisional northward convergence of the southwest Tian Shan, NW China[J]. TECTONOPHYSICS,2005,409(1-4):107-124.
APA	Huang, BC,Piper, JDA,Wang, YC,He, HY,&Zhu, RX.(2005).Paleornagnetic and geochronological constraints on the post-collisional northward convergence of the southwest Tian Shan, NW China.TECTONOPHYSICS,409(1-4),107-124.
MLA	Huang, BC,et al."Paleornagnetic and geochronological constraints on the post-collisional northward convergence of the southwest Tian Shan, NW China".TECTONOPHYSICS 409.1-4(2005):107-124.