{"title":"中亚新太古代基底、地幔富集与地壳萃取:中国东北2.5 Ga角闪岩和变质长岩的岩石成因","authors":"Huichuan Liu, Jun Shao, G. Zhu, Yinglei Li","doi":"10.2475/09.2021.03","DOIUrl":null,"url":null,"abstract":"Archean basement in the Central Asian Orogenic Belt (CAOB) is relatively rare, but it has the potential to provide additional information on the processes of lithospheric mantle enrichment and crust extraction processes during the early history of the Earth. We identified Neoarchean amphibolite (2537−2565 Ma) and metadiorite (2481−2539 Ma) in the Biliya area of the Erguna Terrane in the southeast CAOB. The amphibolite is geochemically MORB-like and has a weakly left-leaning REE pattern, and low zircon εHf(t) (−0.7−+6.2), and whole-rock εNd(t) (−1.7–+4.5) and εHf(t) (−1.9) values. Our petrogenetic modeling reveals that the amphibolite is derived from ∼20 % partial melting of the lithospheric mantle in the spinel stability field (∼65 km depth). The metadiorite shows near-zero εNd(t) (−0.5–+3.6) and εHf(t) (+0.5–+1.4) values and is likely derived from partial melting of mafic lower crust. The metadiorite and amphibolite likely formed in an extensional continental arc/back-arc setting and represent the Archean crystalline basement of the microcontinents within the CAOB. Three-staged mantle segregation and crust extraction processes have been proposed: (a) 20 % melt extraction from primitive mantle-like lithospheric mantle, leaving behind a depleted mantle; (b) subduction-related fluid/melt metasomatism of the lithospheric mantle and its partial melting, generating the arc-type enriched mantle and mafic lower crust; and (c) partial remelting of the mafic lower crust produced the Tonalite-trondhjemite-granodiorite (TTG) crust.","PeriodicalId":7660,"journal":{"name":"American Journal of Science","volume":"321 1","pages":"1350 - 1379"},"PeriodicalIF":1.9000,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"2","resultStr":"{\"title\":\"Neoarchean basement, mantle enrichment and crustal extraction in central Asia: petrogenesis of 2.5 Ga amphibolite and metadiorite in NE China\",\"authors\":\"Huichuan Liu, Jun Shao, G. Zhu, Yinglei Li\",\"doi\":\"10.2475/09.2021.03\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"Archean basement in the Central Asian Orogenic Belt (CAOB) is relatively rare, but it has the potential to provide additional information on the processes of lithospheric mantle enrichment and crust extraction processes during the early history of the Earth. We identified Neoarchean amphibolite (2537−2565 Ma) and metadiorite (2481−2539 Ma) in the Biliya area of the Erguna Terrane in the southeast CAOB. The amphibolite is geochemically MORB-like and has a weakly left-leaning REE pattern, and low zircon εHf(t) (−0.7−+6.2), and whole-rock εNd(t) (−1.7–+4.5) and εHf(t) (−1.9) values. Our petrogenetic modeling reveals that the amphibolite is derived from ∼20 % partial melting of the lithospheric mantle in the spinel stability field (∼65 km depth). The metadiorite shows near-zero εNd(t) (−0.5–+3.6) and εHf(t) (+0.5–+1.4) values and is likely derived from partial melting of mafic lower crust. The metadiorite and amphibolite likely formed in an extensional continental arc/back-arc setting and represent the Archean crystalline basement of the microcontinents within the CAOB. Three-staged mantle segregation and crust extraction processes have been proposed: (a) 20 % melt extraction from primitive mantle-like lithospheric mantle, leaving behind a depleted mantle; (b) subduction-related fluid/melt metasomatism of the lithospheric mantle and its partial melting, generating the arc-type enriched mantle and mafic lower crust; and (c) partial remelting of the mafic lower crust produced the Tonalite-trondhjemite-granodiorite (TTG) crust.\",\"PeriodicalId\":7660,\"journal\":{\"name\":\"American Journal of Science\",\"volume\":\"321 1\",\"pages\":\"1350 - 1379\"},\"PeriodicalIF\":1.9000,\"publicationDate\":\"2021-11-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"2\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"American Journal of Science\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://doi.org/10.2475/09.2021.03\",\"RegionNum\":3,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"GEOSCIENCES, MULTIDISCIPLINARY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"American Journal of Science","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.2475/09.2021.03","RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"GEOSCIENCES, MULTIDISCIPLINARY","Score":null,"Total":0}
Neoarchean basement, mantle enrichment and crustal extraction in central Asia: petrogenesis of 2.5 Ga amphibolite and metadiorite in NE China
Archean basement in the Central Asian Orogenic Belt (CAOB) is relatively rare, but it has the potential to provide additional information on the processes of lithospheric mantle enrichment and crust extraction processes during the early history of the Earth. We identified Neoarchean amphibolite (2537−2565 Ma) and metadiorite (2481−2539 Ma) in the Biliya area of the Erguna Terrane in the southeast CAOB. The amphibolite is geochemically MORB-like and has a weakly left-leaning REE pattern, and low zircon εHf(t) (−0.7−+6.2), and whole-rock εNd(t) (−1.7–+4.5) and εHf(t) (−1.9) values. Our petrogenetic modeling reveals that the amphibolite is derived from ∼20 % partial melting of the lithospheric mantle in the spinel stability field (∼65 km depth). The metadiorite shows near-zero εNd(t) (−0.5–+3.6) and εHf(t) (+0.5–+1.4) values and is likely derived from partial melting of mafic lower crust. The metadiorite and amphibolite likely formed in an extensional continental arc/back-arc setting and represent the Archean crystalline basement of the microcontinents within the CAOB. Three-staged mantle segregation and crust extraction processes have been proposed: (a) 20 % melt extraction from primitive mantle-like lithospheric mantle, leaving behind a depleted mantle; (b) subduction-related fluid/melt metasomatism of the lithospheric mantle and its partial melting, generating the arc-type enriched mantle and mafic lower crust; and (c) partial remelting of the mafic lower crust produced the Tonalite-trondhjemite-granodiorite (TTG) crust.
期刊介绍:
The American Journal of Science (AJS), founded in 1818 by Benjamin Silliman, is the oldest scientific journal in the United States that has been published continuously. The Journal is devoted to geology and related sciences and publishes articles from around the world presenting results of major research from all earth sciences. Readers are primarily earth scientists in academia and government institutions.