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DOI	10.1007/s00410-024-02135-y
	Dynamics of the oceanic dike-gabbro transition revealed by petrology and geochemistry of the Yunzhug ophiolite, central Tibet
	Liu, Tong; Liu, Chuan-Zhou; Zhang, Zhen-Yu; Zhang, Wei-Qi; Ji, Wen-Bin; Zhang, Chang; Mitchell, Ross N.
发表日期	2024
ISSN	0010-7999
EISSN	1432-0967
起始页码	179
结束页码	5
卷号	179 期号:5
英文摘要	The dynamics and magma transport at the boundary between the upper and lower oceanic crusts (i.e., the dike-gabbro transition) are crucial for understanding the crustal accretion beneath mid-ocean ridges, which however have been studied at quite a few sites such as the East Pacific Rise and ophiolites like Troodos and Oman. Here we present detailed geological, petrological, and geochemical data for the dike-gabbro transition and associated basalts in the Yunzhug ophiolite, central Tibet, to constrain the complex magmatic processes in this specific horizon. The Yunzhug ophiolite contains a large (similar to 20 km(2)) well-exposed sheeted dike complex, which is rooted in a dike-gabbro transition that consists of diverse lithologies, including diabase, gabbro, and minor porphyritic diabase. Petrographically, the Yunzhug gabbros could be grouped into the dominant Plg (plagioclase)-euhedral gabbros (euhedral-subhedral plagioclases enclosed in clinopyroxene oikocrysts) and a small amount of Cpx (clinopyroxene)-euhedral gabbros (with abundant euhedral clinopyroxenes). Plagioclases and their equilibrated melts of the two types of gabbros are similar, whereas clinopyroxenes and their equilibrated melts of the Cpx-euhedral gabbros are more primary and depleted than those of the Plg-euhedral gabbros. These petrographic and geochemical features suggest an earlier crystallization of clinopyroxene for the Cpx-euhedral gabbros, which is best explained by occasional water input in the magmatic system. Nevertheless, the modeled equilibrated melts of the two types of gabbros have compositions indistinguishable from the whole rock compositions of diabases and basalts, indicating a direct genetic linkage between these rocks. The unusual porphyritic diabases, on the other hand, provide evidence supporting for plagioclase accumulation and aggregation during magma upward migration, thus may have served as a unique way for magma to transport from the lower to upper crust. Studies of the Yunzhug ophiolite thus provide some key constraints on the complex magmatic processes in the oceanic dike-gabbro transition, regarding its dynamic accretion and magmatic plumbing mechanisms.
英文关键词	Dynamic accretion; Magmatic plumbing mechanism; Oceanic dike-gabbro transition; Yunzhug ophiolite; Tibetan Plateau
语种	英语
WOS研究方向	Geochemistry & Geophysics ; Mineralogy
WOS类目	Geochemistry & Geophysics ; Mineralogy
WOS记录号	WOS:001220780500001
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/291174
作者单位	Chinese Academy of Sciences; Institute of Geology & Geophysics, CAS; Laoshan Laboratory; Northwest University Xi'an
推荐引用方式 GB/T 7714	Liu, Tong,Liu, Chuan-Zhou,Zhang, Zhen-Yu,et al. Dynamics of the oceanic dike-gabbro transition revealed by petrology and geochemistry of the Yunzhug ophiolite, central Tibet[J],2024,179(5).
APA	Liu, Tong.,Liu, Chuan-Zhou.,Zhang, Zhen-Yu.,Zhang, Wei-Qi.,Ji, Wen-Bin.,...&Mitchell, Ross N..(2024).Dynamics of the oceanic dike-gabbro transition revealed by petrology and geochemistry of the Yunzhug ophiolite, central Tibet.CONTRIBUTIONS TO MINERALOGY AND PETROLOGY,179(5).
MLA	Liu, Tong,et al."Dynamics of the oceanic dike-gabbro transition revealed by petrology and geochemistry of the Yunzhug ophiolite, central Tibet".CONTRIBUTIONS TO MINERALOGY AND PETROLOGY 179.5(2024).