气候变化领域集成服务门户(CCPortal): Crustal accretion in a slow-spreading center of Meso-Tethyan Ocean: Constraints from cumulates in the Dongco ophiolite (Central Tibet)

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DOI	10.1016/j.lithos.2023.107144
	Crustal accretion in a slow-spreading center of Meso-Tethyan Ocean: Constraints from cumulates in the Dongco ophiolite (Central Tibet)
	Li, Xiao-Ni; Zhang, Wei-Qi; Liu, Tong; Zhang, Chang; Zhang, Zhen; Lin, Yin-Zheng; Liu, Chuan-Zhou
发表日期	2023
ISSN	0024-4937
EISSN	1872-6143
卷号	446
英文摘要	Lower ocean crustal rocks are important for deciphering magmatic processes in the magma chamber during the generation of the ophiolite. Gabbroic cumulates are volumetrically outcropped in the Dongco ophiolite in the Bangong-Nujiang Suture, which are pervasively intruded by diabase dikes. This study presents mineralogical, geochemical, and geochronological data of the Dongco cumulates to constrain their parental magma compositions and the tectonic setting of the Dongco ophiolite. Zircons and titanites from six gabbros yielded U-Pb ages of 159-166 Ma, suggesting that the Dongco ophiolite was generated during Middle to Late Jurassic. Petrological and major element data of the Dongco cumulates suggest that they were derived from water-poor magmas (similar to 0.5-1.0 wt% H2O) via low-pressure crystallization. Clinopyroxenes of the Dongco cumulates have lower Ti, Zr, and REE but higher Ba abundances compared to those in mid-ocean ridge cumulates. Melts in equilibrium with clinopyroxene of the Dongco cumulates are estimated to compositionally resemble the diabase dikes, both of which share similarities with island arc basalts, e.g., enrichments in Ba, Sr and Pb but depletions in REE and Nb. Moreover, the Dongco cumulates have been inferred to experience rapid exhumation shortly after its emplacement. Therefore, we propose that the Dongco cumulates were generated at a slow-spreading center in a backarc basin. The Dongco ophiolite in the Bangong-Nujiang suture and the Lagkorco ophiolite in the Shiquanhe-Yunzhug-Namco suture share great similarities in their formation ages, spreading rate and tectonic setting, which supports that the western Shiquanhe-Yunzhug-Namco suture is the southward-thrusted nappe of the Bangong-Nujiang suture.
关键词	Lower oceanic crust Gabbro Dongco ophiolite Bangong-Nujiang Suture Slow-spreading ridge
英文关键词	BANGONG-NUJIANG SUTURE; PHASE-EQUILIBRIA; U-PB; GEOCHEMISTRY; EVOLUTION; ZONE; GEOCHRONOLOGY; WATER; CLINOPYROXENE; EXHUMATION
WOS研究方向	Geochemistry & Geophysics ; Mineralogy
WOS记录号	WOS:001058602700001
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/283511
作者单位	Chinese Academy of Sciences; Institute of Geology & Geophysics, CAS; Laoshan Laboratory; Chinese Academy of Sciences; University of Chinese Academy of Sciences, CAS
推荐引用方式 GB/T 7714	Li, Xiao-Ni,Zhang, Wei-Qi,Liu, Tong,et al. Crustal accretion in a slow-spreading center of Meso-Tethyan Ocean: Constraints from cumulates in the Dongco ophiolite (Central Tibet)[J],2023,446.
APA	Li, Xiao-Ni.,Zhang, Wei-Qi.,Liu, Tong.,Zhang, Chang.,Zhang, Zhen.,...&Liu, Chuan-Zhou.(2023).Crustal accretion in a slow-spreading center of Meso-Tethyan Ocean: Constraints from cumulates in the Dongco ophiolite (Central Tibet).LITHOS,446.
MLA	Li, Xiao-Ni,et al."Crustal accretion in a slow-spreading center of Meso-Tethyan Ocean: Constraints from cumulates in the Dongco ophiolite (Central Tibet)".LITHOS 446(2023).