气候变化领域集成服务门户(CCPortal): Lithofacies, geochemistry, and sequences of basalt and carbonate rocks of a Middle Permian composite seamount (central Yarlung Zangbo Suture Zone, Tibet): Implications to the incipient opening of the Neo-Tethys Ocean

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DOI	10.1016/j.lithos.2023.107175
	Lithofacies, geochemistry, and sequences of basalt and carbonate rocks of a Middle Permian composite seamount (central Yarlung Zangbo Suture Zone, Tibet): Implications to the incipient opening of the Neo-Tethys Ocean
	Fan, Xiaolong; Li, Xianghui; Mattern, Frank; Wei, Zhen; Zheng, Chenyu; Wang, Jingyu; Zhou, Min
发表日期	2023
ISSN	0024-4937
EISSN	1872-6143
卷号	448
英文摘要	Neo-Tethyan paleo-seamounts remain poorly understood due to the scarcity of key holistic evidence although some cases have been reported. This work focuses on a Middle Permian (Guadalupian) composite seamount in the central Yarlung Zangbo Suture Zone, using textures and sequences of its basaltic basement and carbonate cap to characterize the development of the oceanic crust. We conducted field investigations, lithological studies, and geochemical analyses of a huge composite rock block (the Buma paleo-seamount) north of Lang Co, Ngamring, Tibet. Results show that the basement rocks are mainly subaqueously erupted, tholeiitic basalts, which are very similar to the Hawaiian oceanic island basalts (OIB-types) in terms of geochemistry and tectonic setting; and the cap rocks are characterized by four general sedimentary facies and ten limestone microfacies, all of which are primarily of shallow marine nature. Four different contact relationships between basement and cap rocks are further recognized as regular, scouring, brecciation, and karstification types. Together, they demonstrate that multiple complete sequences of basalt basement and sedimentary cap, rich in bryozoans (reef/atoll) and crinoids exist, representing the composite seamount in the central Yarlung Zangbo Suture Zone. At least eight sets of seamount sub-sequences are superimposed as submerged and subaerial types, recording the oceanic crustal evolution of the Neo-Tethys Ocean during the Guadalupian epoch. Particularly, residual basaltic and karst breccia indicate subaerial exposure and, thus, prove an island stage. Taking into account the average mature seamount lifespan of similar to 26 Ma and the complete sequence of the newly recognized Buma seamount in an intraplate setting, we propose that the incipient opening of the eastern Neo-Tethys could have taken place much earlier than the Guadalupian (Middle Permian), likely during the Cisuralian (Early Permian) or even earlier.
关键词	OIB-type basement Microfacies Limestone cap Seamount sequence Initiation of Neo-Tethys Ocean Guadalupian epoch
英文关键词	SOUTHERN TIBET; MANTLE SOURCES; EVOLUTION; CLASSIFICATION; SEDIMENTARY; HISTORY; LITHOSPHERE; OPHIOLITES; TECTONICS; ACCRETION
WOS研究方向	Geochemistry & Geophysics ; Mineralogy
WOS记录号	WOS:000990697200001
来源期刊	LITHOS
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/283324
作者单位	Nanjing University; Xinjiang University
推荐引用方式 GB/T 7714	Fan, Xiaolong,Li, Xianghui,Mattern, Frank,et al. Lithofacies, geochemistry, and sequences of basalt and carbonate rocks of a Middle Permian composite seamount (central Yarlung Zangbo Suture Zone, Tibet): Implications to the incipient opening of the Neo-Tethys Ocean[J],2023,448.
APA	Fan, Xiaolong.,Li, Xianghui.,Mattern, Frank.,Wei, Zhen.,Zheng, Chenyu.,...&Zhou, Min.(2023).Lithofacies, geochemistry, and sequences of basalt and carbonate rocks of a Middle Permian composite seamount (central Yarlung Zangbo Suture Zone, Tibet): Implications to the incipient opening of the Neo-Tethys Ocean.LITHOS,448.
MLA	Fan, Xiaolong,et al."Lithofacies, geochemistry, and sequences of basalt and carbonate rocks of a Middle Permian composite seamount (central Yarlung Zangbo Suture Zone, Tibet): Implications to the incipient opening of the Neo-Tethys Ocean".LITHOS 448(2023).