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DOI	10.1016/j.epsl.2023.118519
	Exploring hindered decarbonation in contact metamorphism: A glimpse into marble aureoles in Southern Tibet
	Zhou, Zhenhao; Chu, Xu; Tang, Ming; Leybourne, Matthew
发表日期	2024
ISSN	0012-821X
EISSN	1385-013X
卷号	626
英文摘要	Fluid-driven contact metamorphism in the Gangdese Arc, resulting from Late Cretaceous intrusions, led to a diverse range of aureoles in carbonate sequences in southern Tibet. These include extensive carbon loss in calcsilicate rocks with minor calcite remnants and minimal carbon loss in predominantly pure marble formations. Many studies connecting contact metamorphism and decarbonation flux focus on metacarbonate aureoles comprising calc-silicate assemblages, while marble formations represent a less prominent endmember. To investigate the factors determining decarbonation extent, we analyzed the thermobarometric, geochemical, and isotopic signatures of two representative marble aureoles in southern Tibet. Our findings suggest that isobarically exsolved magmatic fluid from a neighboring similar to 64 Ma granodiorite pluton led to limited fluid-rock interaction in the marble aureole. Based on the petrologic observations, we present a conceptual model to elucidate this process. The heating and fluid infiltration were brief, likely due to short-lived intrusion events. Consequently, a thin ductile layer was formed adjacent to the pluton, while the majority of the country rock remained brittle. The lithostatic fluid in the ductile layer likely escaped through structurally weak zones, creating veins along the boundary between the pluton and marble. The fluids traversed the brittle-ductile transition experienced a sudden pressure drop from lithostatic in the ductile rock to hydrostatic in the brittle regime. The boiling fluid escaped by brecciating the brittle country rock and resulted in brecciation and stockwork of veins. In both cases, most fluid escaped through pathways, preventing infiltration into the country rock and decarbonation reactions. In contrast, a longer-lived heat source would have produced more extensive ductile country rocks, allowing for widespread fluid infiltration and calc-silicate formation. Thus, the thermal history of the intrusion and the rheology of the country rock significantly influence the extent of decarbonation in contact aureoles.
关键词	Marble Decarbonation Southern Tibet Quartz vein
英文关键词	DEPENDENT THERMAL-DIFFUSIVITY; OXYGEN ISOTOPE FRACTIONATION; FLUID-FLOW; GANGDESE BATHOLITH; SYSTEM H2O-NACL; CARBON-ISOTOPE; TEMPERATURE; TRANSPORT; PRESSURE; ARC
WOS研究方向	Geochemistry & Geophysics
WOS记录号	WOS:001134619000001
来源期刊	EARTH AND PLANETARY SCIENCE LETTERS
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/282625
作者单位	University of Toronto; Peking University; Queens University - Canada; Queens University - Canada
推荐引用方式 GB/T 7714	Zhou, Zhenhao,Chu, Xu,Tang, Ming,et al. Exploring hindered decarbonation in contact metamorphism: A glimpse into marble aureoles in Southern Tibet[J],2024,626.
APA	Zhou, Zhenhao,Chu, Xu,Tang, Ming,&Leybourne, Matthew.(2024).Exploring hindered decarbonation in contact metamorphism: A glimpse into marble aureoles in Southern Tibet.EARTH AND PLANETARY SCIENCE LETTERS,626.
MLA	Zhou, Zhenhao,et al."Exploring hindered decarbonation in contact metamorphism: A glimpse into marble aureoles in Southern Tibet".EARTH AND PLANETARY SCIENCE LETTERS 626(2024).