Pure sediment-derived granites in a subduction zone

doi:10.1130/B36016.1

GIG OpenIR

	Xu, Jian 1,2; Xiao-Ping Xia 1,2; Wang, Qiang 1,2; Spencer, Christopher J.3; Chun-Kit Lai 4; Jin-Long Ma 1,2; Zhang, Le 1,2; Ze-Xian Cui 1,2,5; Wan-Feng Zhang 1,2; Yan-Qiang Zhang 1,2
	Pure sediment-derived granites in a subduction zone
刊名	GEOLOGICAL SOCIETY OF AMERICA BULLETIN
ISSN号	0016-7606
	2022-03-01
卷号	134 期号:3-4 页码:599-615
DOI	10.1130/B36016.1
语种	英语
WOS研究方向	Geology
摘要	The Earth is unique in the Solar System due to significant volumes of granite in the lithosphere. However, the origins of granites are still highly debated, especially sediment derived granites, which are often treated as a geochemical end-member of the continental crust. In the Yunnan region of South China, we identify the occurrence of pure sediment derived granite in a subduction system. The suite of strongly peraluminous granite reported herein is interpreted to represent pure metasedimentary melts based on their whole rock elemental and Sr-Nd-B and zircon Hf-O isotopic compositions. These Late Permian- Early Triassic (ca. 254-248 Ma) granites are characterized by radiogenically enriched Sr, Nd, and Hf isotopic signatures. They show delta B-11 and delta O-18 signatures akin to those of continental shales. Geochemical modeling indicates no contributions from the mantle that can be detected. Considering the regional tectonic evolution, these granites are suggested to be formed in a subduction zone by decompression melting of rapidly exhumed back arc sediments. We posit that decompression melting was triggered by widespread extension and thinning of the crust prompted by rollback of the subducting oceanic crust. These granites thus provide evidence that granite formation in subduction zones does not necessarily contribute to crustal growth. These subduction-related pure sediment-derived granites have different elemental ratios and contents (e.g., Al2O3/TiO2 and Yb) from the Himalayan leucogranites. Considering their source compositions (e.g., pelitic rocks), which are similar to those of the Himalayan leucogranites, these differences are likely due to their higher formation temperature and lower pressure despite a great similarity in isotopic compositions. Identification of pure sediment-derived, strongly peraluminous granites (SPGs) in subduction systems provides an important geodynamic mechanism for crustal anatexis, which can both geochemically and tectonically complement their collisional counterparts identified in the Himalayas.
WOS记录号	WOS:000765017600004
收录类别	SCI
引用统计
文献类型	期刊论文
条目标识符	http://ir.gig.ac.cn/handle/344008/67613
通讯作者	Xiao-Ping Xia
作者单位	1.Chinese Acad Sci, Guangzhou Inst Geochem, State Key Lab Isotope Geochem, Guangzhou 510640, Peoples R China 2.Chinese Acad Sci, Ctr Excellence Deep Earth Sci, Guangzhou 510640, Peoples R China 3.Queens Univ, Dept Geol Sci & Geol Engn, Kingston, ON, Canada 4.Univ Brunei Darussalam, Fac Sci, BE-1410 Gadong, Brunei 5.Univ Chinese Acad Sci, Coll Earth & Planetary Sci, Beijing 10100049, Peoples R China
推荐引用方式 GB/T 7714	Xu, Jian,Xiao-Ping Xia,Wang, Qiang,et al. Pure sediment-derived granites in a subduction zone[J]. GEOLOGICAL SOCIETY OF AMERICA BULLETIN,2022,134(3-4):599-615.
APA	Xu, Jian.,Xiao-Ping Xia.,Wang, Qiang.,Spencer, Christopher J..,Chun-Kit Lai.,...&Yan-Qiang Zhang.(2022).Pure sediment-derived granites in a subduction zone.GEOLOGICAL SOCIETY OF AMERICA BULLETIN,134(3-4),599-615.
MLA	Xu, Jian,et al."Pure sediment-derived granites in a subduction zone".GEOLOGICAL SOCIETY OF AMERICA BULLETIN 134.3-4(2022):599-615.