地球演化历史中氧逸度变化对壳幔循环启动、风化和超大陆循环的指示  

Zircons reveal the history of fluctuations in oxidation state of crustal magmatism and supercontinent cycle

作　　者：王瑞 邬绍宸 Roberto F.Weinberg William J.Collins Peter A.Cawood Rui Wang;Shao-chen Wu;Roberto F.Weinberg;William J.Collins;Peter A.Cawood(State Key Laboratory of Geological Processes and Mineral Resources,Institute of Earth Sciences,China University of Geosciences,Beijing 100083,China;Frontiers Science Center for Deep-time Digital Earth,China University of Geosciences(Beijing),Beijing 100083,China;School of Earth,Atmosphere and Environment,Monash University,Clayton VIC 3800,Australia;The Institute for Geoscience Research,Curtin University,Perth WA 6102,Australia)

机构地区：[1]State Key Laboratory of Geological Processes and Mineral Resources,Institute of Earth Sciences,China University of Geosciences,Beijing 100083,China [2]Frontiers Science Center for Deep-time Digital Earth,China University of Geosciences(Beijing),Beijing 100083,China [3]School of Earth,Atmosphere and Environment,Monash University,Clayton VIC 3800,Australia [4]The Institute for Geoscience Research,Curtin University,Perth WA 6102,Australia

出　　处：《Science Bulletin》2024年第1期97-102,共6页科学通报（英文版）

基　　金：the National Natural Science Foundation of China(42225204 and 42121002);support from the Australian Research Council(FL160100168);the Fundamental Research Funds for the Central Universities(2652023001);the Programme of Introducing Talents of Discipline to Universities(111 Project,B18048)。

摘　　要：We apply a zircon redox index to a global compilation of detrital zircons to track the variation of oxidation state,expressed asΔFMQ,through Earth's history.Those from I-type rocks,which comprise mantle and crustal igneous protoliths,including tonalite–trondhjemite–granodiorites(TTGs),generally have a high oxidation state(ΔFMQ>0).In contrast,zircons from igneous rocks derived from supracrustal source rocks(S-type)are commonly reduced(ΔFMQ<0).With the probability density function derived from the Gaussian-Kernel-Density-Estimation,we use the maximum likelihood estimation(MLE)to distinguish Stype from I-type zircons through Earth's history using zircon redox.Voluminous S-type magma production shows a ca.600 Ma cyclicity that is closely related to the supercontinent cycle.We link a cyclic drop in redox values after 2.6 Ga to periodic S-type magma generation associated with burial and melting of metasedimentary rocks during supercontinent assembly and amalgamation.TheΔFMQ of the detrital zircons rise at~3.5 Ga followed by a consistent averageΔFMQ>0 over the last 3 Ga.Given that the redox state of magmas is independent of crustal thickness and silica variation,and elevated values are likely more closely related to tectonic setting,we suggest that the consistent averageΔFMQ>0 from ca.3.5 Ga onwards relates to recycling of oceanic lithosphere back into the mantle in what eventually became established as subduction zones.The more reduced magmas associated with sedimentary sources,became established at 2.6 Ga,presumably in response to continental rocks rising above sealevel,and follow peaks of productivity associated with the supercontinent cycle.

关 键 词：Oxidation state SUPERCONTINENT Weathering SUBDUCTION ZIRCON Granite 

分 类 号：P542[天文地球—构造地质学]