气候变化领域集成服务门户(CCPortal): Slab-derived devolatilization fluids oxidized by subducted metasedimentary rocks

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DOI	10.1038/s41561-022-00904-7
	Slab-derived devolatilization fluids oxidized by subducted metasedimentary rocks
	Ague, Jay J.; Tassara, Santiago; Holycross, Megan E.; Ji-Lei Li; Cottrell, Elizabeth; Schwarzenbach, Esther M.; Fassoulas, Charalampos; John, Timm
发表日期	2022
ISSN	1752-0894
EISSN	1752-0908
起始页码	320
结束页码	+
卷号	15 期号:4 页码:12
英文摘要	Metasedimentary rocks atop the downgoing slab oxidize ascending slab-derived dehydration fluids by removing reduced species, according to petrological analysis of subduction complex metasedimentary rocks and reactive transport modelling. Metamorphic devolatilization of subducted slabs generates aqueous fluids that ascend into the mantle wedge, driving the partial melting that produces arc magmas. These magmas have oxygen fugacities some 10-1,000 times higher than magmas generated at mid-ocean ridges. Whether this oxidized magmatic character is imparted by slab fluids or is acquired during ascent and interaction with the surrounding mantle or crust is debated. Here we study the petrology of metasedimentary rocks from two Tertiary Aegean subduction complexes in combination with reactive transport modelling to investigate the oxidative potential of the sedimentary rocks that cover slabs. We find that the metasedimentary rocks preserve evidence for fluid-mediated redox reactions and could be highly oxidized. Furthermore, the modelling demonstrates that layers of these oxidized rocks less than about 200 m thick have the capacity to oxidize the ascending slab dehydration flux via redox reactions that remove H-2, CH4 and/or H2S from the fluids. These fluids can then oxidize the overlying mantle wedge at rates comparable to arc magma generation rates, primarily via reactions involving sulfur species. Oxidized metasedimentary rocks need not generate large amounts of fluid themselves but could instead oxidize slab dehydration fluids ascending through them. Proposed Phanerozoic increases in arc magma oxygen fugacity may reflect the recycling of oxidative weathering products following Neoproterozoic-Palaeozoic marine and atmospheric oxygenation.
学科领域	Geosciences, Multidisciplinary
语种	英语
WOS研究方向	Geology
WOS记录号	WOS:000770230700001
来源期刊	NATURE GEOSCIENCE
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/272530
作者单位	Yale University; Yale University; Cornell University; Chinese Academy of Sciences; Institute of Geology & Geophysics, CAS; Chinese Academy of Sciences; Smithsonian Institution; Smithsonian National Museum of Natural History; Free University of Berlin; University of Crete
推荐引用方式 GB/T 7714	Ague, Jay J.,Tassara, Santiago,Holycross, Megan E.,et al. Slab-derived devolatilization fluids oxidized by subducted metasedimentary rocks[J],2022,15(4):12.
APA	Ague, Jay J..,Tassara, Santiago.,Holycross, Megan E..,Ji-Lei Li.,Cottrell, Elizabeth.,...&John, Timm.(2022).Slab-derived devolatilization fluids oxidized by subducted metasedimentary rocks.NATURE GEOSCIENCE,15(4),12.
MLA	Ague, Jay J.,et al."Slab-derived devolatilization fluids oxidized by subducted metasedimentary rocks".NATURE GEOSCIENCE 15.4(2022):12.