Massive sediment accretion at similar to 80 km depth along the subduction interface: Evidence from the southern Chinese Tianshan

doi:10.1130/G40201.1

CORC > 地质与地球物理研究所 > 中国科学院地质与地球物理研究所 > 中国科学院矿产资源研究重点实验室

	Massive sediment accretion at similar to 80 km depth along the subduction interface: Evidence from the southern Chinese Tianshan
	Bayet, Lea 1; John, Timm 1; Agard, Philippe 2; Gao, Jun 3; Li, Ji-Lei 3
刊名	GEOLOGY
	2018-06-01
卷号	46 期号:6 页码:495-498
ISSN号	0091-7613
DOI	10.1130/G40201.1
文献子类	Article
英文摘要	Sediment burial to depths beyond 60 km is documented by rare exposures and inferred from mass-balance calculations, element recycling, and numerical modeling. Although thermomechanical and geochemical models have suggested potential diapirism of subducted metasediments, natural evidence of this remains scarce, especially for large volumes. The southern Tianshan metamorphic belt (northwest China) represents a unique example of a deeply buried, similar to 4-5-km-thick, coesite-bearing sequence dominated by trench infill metasediments, with kilometer-scale variations in volcanoclastic and pelitic components. We demonstrate that these rocks were subducted down to similar to 80 km, as shown by evenly distributed pressure-temperature conditions of 2.5 +/- 0.2 GPa and 536 +/- 11 C-degrees. Considering sedimentary budgets and geophysical constraints on subduction channel thickness (<2-5 km), this sequence likely detached as several 0.5-1.0-km-thick individual slices, and later accreted to the upper plate within >2 m.y. Results show that temperatures were buffered and cold (<550 C-degrees), suggesting continuous refrigeration (by incoming cold material from the slab, juxtaposition to a mantle wedge "cold nose", presence of a thick overriding plate, and/or fluid circulation along the plate interface). The absence of evidence for diapirism in this buoyant metasedimentary package, at similar to 540 C-degrees and 80 km depth, suggests that metasedimentary diapirs may occur only at greater depth and/or farther away from the plate interface.
WOS关键词	NW-CHINA ; ULTRAHIGH-PRESSURE ; WESTERN TIANSHAN ; CRUST ; METAMORPHISM ; EXHUMATION ; MOUNTAINS ; EVOLUTION ; ECLOGITE ; COESITE
WOS研究方向	Geology
语种	英语
出版者	GEOLOGICAL SOC AMER, INC
WOS记录号	WOS:000433513800007
资助机构	People Programme (Marie Curie Actions) of the European Union's Seventh Framework Programme FP7/under REA grant(604713) ; People Programme (Marie Curie Actions) of the European Union's Seventh Framework Programme FP7/under REA grant(604713) ; People Programme (Marie Curie Actions) of the European Union's Seventh Framework Programme FP7/under REA grant(604713) ; People Programme (Marie Curie Actions) of the European Union's Seventh Framework Programme FP7/under REA grant(604713) ; People Programme (Marie Curie Actions) of the European Union's Seventh Framework Programme FP7/under REA grant(604713) ; People Programme (Marie Curie Actions) of the European Union's Seventh Framework Programme FP7/under REA grant(604713) ; People Programme (Marie Curie Actions) of the European Union's Seventh Framework Programme FP7/under REA grant(604713) ; People Programme (Marie Curie Actions) of the European Union's Seventh Framework Programme FP7/under REA grant(604713)
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/88261]
专题	地质与地球物理研究所_中国科学院矿产资源研究重点实验室
通讯作者	Bayet, Lea
作者单位	1.Free Univ Berlin, Inst Geol Wissensch, Malteserstr 74-100, D-12449 Berlin, Germany 2.UPMC, Sorbonne Univ, UMR CNRS 7193, ISTEP, F-75005 Paris, France 3.Chinese Acad Sci, Inst Geol & Geophys, POB 9825, Beijing 100029, Peoples R China
推荐引用方式 GB/T 7714	Bayet, Lea,John, Timm,Agard, Philippe,et al. Massive sediment accretion at similar to 80 km depth along the subduction interface: Evidence from the southern Chinese Tianshan[J]. GEOLOGY,2018,46(6):495-498.
APA	Bayet, Lea,John, Timm,Agard, Philippe,Gao, Jun,&Li, Ji-Lei.(2018).Massive sediment accretion at similar to 80 km depth along the subduction interface: Evidence from the southern Chinese Tianshan.GEOLOGY,46(6),495-498.
MLA	Bayet, Lea,et al."Massive sediment accretion at similar to 80 km depth along the subduction interface: Evidence from the southern Chinese Tianshan".GEOLOGY 46.6(2018):495-498.