研究进展

Kusky, Timothy et al., EARTH-SCIENCE REVIEWS-2022

发表时间:2022-06-22来源:ok138太阳集团中国官方网站点击:

Vestiges of early Earth's deep subduction and CHONSP cycle recorded in Archean ophiolitic podiform chromitites

作者:

Kusky, T (Kusky, Timothy) [1] , [2] ;     Huang, Y (Huang, Yang) [1] , [5] ;     Wang, L (Wang, Lu) [1] ;     Robinson, PT (Robinson, Paul T.) [1] ;     Wirth, R (Wirth, Richard) [1] , [3] ;     Polat, A (Polat, Ali) [1] , [4] ;     Wei, H (Wei, Hu) [1]  

EARTH SCIENCE REVIEWS

227  

文献号

103968

DOI

10.1016/j.earscirev.2022.103968

出版时间

APR 2022

已索引

2022-05-27

文献类型

Article

摘要

Ophiolitic podiform chromitites from Phanerozoic orogens have been shown to preserve a wealth of textures and inclusions that, in some way, trace earlier episodes of subduction and crust mantle interactions, including traces of the major elements Carbon - Hydrogen - Oxygen - Nitrogen - Sulfur - Phosphorous (CHONSP) needed to sustain a habitable planet. Here, we report the first comprehensive documentation of the textures and inclusions of an Archean (circa 2.55 Ga) podiform chromitite from an orogenic ophiolitic melange in China, recording an ancient CHONSP cycle, during the start of Earth's transition from a reducing to an oxidized surface environment during the Great Oxidation Event, providing evidence for a dynamic link of Archean-Paleoproterzoic tectonics, and creation of a habitable planet. The composition of the inclusions indicates profound mixing of crustal and mantle sources in the Archean, and the textures show that they were included in chromite grains that began their growth as spherules that aggregated from immiscible silicate-oxide melts near the mantle transition zone at temperatures above 1900 degrees C, forming host chenmingite at 14 GPa, or about 410 km. The melts then protruded upward in an extensional fore-arc, reacting with host harzburgites, progressively including a wide assortment of previously subducted mineral and rock fragments as xenocrysts and xenoliths in the progressively crystallizing chromite. The inclusions include ultra-high pressure TiO2 (II) stable at 7.5 GPa (or about 270 km) at 1000 degrees C, plus carbonates, hydrous and nominally anhydrous silicates, oxides, base metals, platinum group minerals, previously unidentified OsIrS, and pure carbon as graphite polymers. As the chromite-bearing melts rose further, they finally crystallized near the crust-mantle boundary of a circa 2.55-billion-year-old fore-arc ophiolite, that was soon, by the dawn of the Paleoproterozoic, involved in an arc/continent collision that emplaced the mantle rocks onto a fragment of older continental crust. This early record of inclusion of previously deeply subducted minerals in an orogenic ophiolitic podiform chromitite shows that plate tectonics and subduction have regulated crust-mantle interactions and the life-sustaining deep CHONSP cycles on Earth at least since the Archean, consistent with numerical models showing how C-O-H cycling related to subduction led to a rapid oxygenation of the mantle in the late Archean.

关键词


作者信息

通讯作者地址

Kusky, Timothy       ;    
Wang, Lu    

(通讯作者)

      China Univ Geosci, Ctr Global Tecton, Sch Earth Sci, State Key Lab Geol Proc & Mineral Resources,Wuhan 43 0074, Peoples R China      

所属机构

China University of Geosciences


电子邮件地址

tkusky@gmail.com   wanglu@cug.edu.cn