气候变化领域集成服务门户(CCPortal): Remagnetization of the Jurassic limestones in the Zaduo area, Eastern Qiangtang Terrane (Tibetan Plateau, China): implications for the India-Eurasia collision

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DOI	10.1093/gji/ggab402
	Remagnetization of the Jurassic limestones in the Zaduo area, Eastern Qiangtang Terrane (Tibetan Plateau, China): implications for the India-Eurasia collision
	Fu, Qiang; Yan, Maodu; Dekkers, Mark J.; Guan, Chong; Yu, Liang; Xu, Wanlong; Li, Bingshuai; Feng, Zhantao; Xu, Zunbo; Shen, Miaomiao; Zhang, Dawen
通讯作者	Yan, MD (通讯作者)
发表日期	2021
ISSN	0956-540X
EISSN	1365-246X
起始页码	2073
结束页码	2091
卷号	228 期号:3
英文摘要	A series of terranes were accreted to Eurasia in the region of what is now the Tibetan Plateau, including the Qaidam-Qilian, the Songpan-Ganzi, the Qiangtang, the Lhasa and the Tethyan Himalaya terranes. The drift history of the Qiangtang Terrane and the timing of the Lhasa-Qiangtang collision are controversial. To contribute to this topic, here, we palaeomagnetically investigate the Middle-Upper Jurassic limestones of the Yanshiping group in the Zaduo area (32.5 degrees N, 95.2 degrees E), in the Estern Qiangtang Terrane. Twelve sites (133 samples) were processed. A major challenge in palaeomagnetism is the possibility of remagnetization that interferes with palaeogeographic reconstructions. Both thermal and alternating field demagnetizations were carried out to isolate the characteristic remanent magnetization (ChRM). Despite the positive reversals test, rock magnetic information points to a remagnetized ChRM. The ChRM is residing in stable single-domain (SSD) magnetite grains with cogenetic superparamagnetic (SP) particles. The co-occurreance of SSD and SP magnetites generates distinct rock-magnetic properties often refer to as the 'remagnetized fingerprint' in limestones. This remagnetization process is also manifested by the widespread occurrence of gypsum veinlets in the limestones. The site-mean direction of the 12 sites after tilt-correction is D-s = 30.6 degrees, I-s = 35.6 degrees, kappa(s) = 182.9, alpha(95) = 3.2 degrees, corresponding to a palaeolatitude of similar to 19.7 degrees +/- 2.8 degrees N for the study area. The corresponding palaeopole (59.8 degrees N, 202.7 degrees E with A(95) = 2.8 degrees) points to an NRM acquired after the India-Eurasia collision. The original sediments were likely anoxic because of the high organic carbon fluxes that prevailed during their deposition. After the India-Eurasia collision, it is envisaged that conditions became more oxic, giving rise to oxidation of iron sulphides to authigenic magnetite and the CRM acquisition. The Zaduo area in the Eastern Qiangtang Terrane has experienced similar to 15.7 degrees +/- 3.2 degrees (similar to 1740 +/- 350 km) of latitudinal crustal shortening since the Eocene. In addition, the clockwise rotation responding to the India-Eurasia collision is also detected in the Zaduo area.
关键词	NUJIANG TETHYAN OCEAN ZIRCON U-PB TECTONIC EVOLUTION ACQUISITION CURVES SECONDARY MAGNETIZATIONS ORDOVICIAN CARBONATES CENTRAL APPALACHIANS CLOCKWISE ROTATIONS SEDIMENTARY-ROCKS LHASA-QIANGTANG
英文关键词	Magnetic properties; Asia; Palaeomagnetism; Remagnetization; Rock and mineral magnetism
语种	英语
WOS研究方向	Geochemistry & Geophysics
WOS类目	Geochemistry & Geophysics
WOS记录号	WOS:000776226100001
来源期刊	GEOPHYSICAL JOURNAL INTERNATIONAL
来源机构	中国科学院青藏高原研究所
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/260510
推荐引用方式 GB/T 7714	Fu, Qiang,Yan, Maodu,Dekkers, Mark J.,et al. Remagnetization of the Jurassic limestones in the Zaduo area, Eastern Qiangtang Terrane (Tibetan Plateau, China): implications for the India-Eurasia collision[J]. 中国科学院青藏高原研究所,2021,228(3).
APA	Fu, Qiang.,Yan, Maodu.,Dekkers, Mark J..,Guan, Chong.,Yu, Liang.,...&Zhang, Dawen.(2021).Remagnetization of the Jurassic limestones in the Zaduo area, Eastern Qiangtang Terrane (Tibetan Plateau, China): implications for the India-Eurasia collision.GEOPHYSICAL JOURNAL INTERNATIONAL,228(3).
MLA	Fu, Qiang,et al."Remagnetization of the Jurassic limestones in the Zaduo area, Eastern Qiangtang Terrane (Tibetan Plateau, China): implications for the India-Eurasia collision".GEOPHYSICAL JOURNAL INTERNATIONAL 228.3(2021).