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DOI	10.1007/s00410-023-02040-w
	Generation of ultraslow-spreading oceanic crust traced by various mafic blocks from ophiolitic melange in the Xigaze Ophiolites, southern Tibet
	Zhang, Chang; Liu, Chuan-Zhou; Liu, Tong; Ji, Wen-Bin; Wu, Fu-Yuan
发表日期	2023
ISSN	0010-7999
EISSN	1432-0967
卷号	178 期号:8
英文摘要	Construction of oceanic crusts in ultraslow-spreading ridges are controlled by detachment faults, but the specific ways they are determined by detachments remain unclear. Abundant ophiolite massifs discovered along the Yarlung-Tsangpo Suture Zone, southern Tibet, are considered to represent ultraslow-spreading centers of the Cretaceous Neo-Tethys ocean. The presence of various mafic blocks within the ophiolitic melange beneath the lithospheric mantle provides evidence of the entire processes involved in crustal generation. Therefore, in this study geochemical investigations on these mafic blocks from the southern Luqu (Xigaze) ophiolitic melanges were conducted to shed new lights on the petrogenesis of mafic crust rocks in ultraslow-spreading settings. Geochronological results via zircon U-Pb dating gave evidence for their coeval formation to other Yarlung-Tsangpo ophiolitic crust rocks in the Early Cretaceous (ca. 120-130 Ma). Geochemistry and Sr-Nd-Hf isotopes document depleted and primitive characteristics, revealing that these mafic rocks were crystallized from residual melts experienced substantial fractional crystallization following along liquid lines of descent of H2O-poor magmas. However, amphiboles are pervasive throughout our samples, which is in contrast with expectations of clinopyroxene and plagioclase as dominant liquidus phases of anhydrous magma. Textures of replacement of clinopyroxene by magnesio-hornblende and their higher contents of trace elements and Eu negative anomalies support that the amphiboles crystallized during transition from dry magma to hydrous one, indicative of water additions to solidifying melts. Based on the tectonic settings of ultraslow-spreading centers, we proposed a model in which seawater-derived fluids induced through detachment faults could be responsible for the generation of ultraslow-spreading crust.
关键词	Ophiolites Ultraslow-spreading ridges Detachment faults Yarlung-Tsangpo Suture Zone Neo-Tethyan Lithosphere
英文关键词	ZIRCON U-PB; TEMPERATURE HYDROTHERMAL CIRCULATION; ZANGBO SUTURE ZONE; OMAN OPHIOLITE; ISOTOPIC CONSTRAINTS; GEOCHEMICAL EVIDENCE; MANTLE PERIDOTITE; DETACHMENT FAULTS; WORKING REFERENCE; METAMORPHIC SOLE
WOS研究方向	Geochemistry & Geophysics ; Mineralogy
WOS记录号	WOS:001040259400001
来源期刊	CONTRIBUTIONS TO MINERALOGY AND PETROLOGY
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/283285
作者单位	Chinese Academy of Sciences; Institute of Geology & Geophysics, CAS; Chinese Academy of Sciences; Chinese Academy of Sciences; University of Chinese Academy of Sciences, CAS; Northwest University Xi'an
推荐引用方式 GB/T 7714	Zhang, Chang,Liu, Chuan-Zhou,Liu, Tong,et al. Generation of ultraslow-spreading oceanic crust traced by various mafic blocks from ophiolitic melange in the Xigaze Ophiolites, southern Tibet[J],2023,178(8).
APA	Zhang, Chang,Liu, Chuan-Zhou,Liu, Tong,Ji, Wen-Bin,&Wu, Fu-Yuan.(2023).Generation of ultraslow-spreading oceanic crust traced by various mafic blocks from ophiolitic melange in the Xigaze Ophiolites, southern Tibet.CONTRIBUTIONS TO MINERALOGY AND PETROLOGY,178(8).
MLA	Zhang, Chang,et al."Generation of ultraslow-spreading oceanic crust traced by various mafic blocks from ophiolitic melange in the Xigaze Ophiolites, southern Tibet".CONTRIBUTIONS TO MINERALOGY AND PETROLOGY 178.8(2023).