气候变化领域集成服务门户(CCPortal): Boron isotope insights into the origin of subduction signatures in continent-continent collision zone volcanism

CCPortal

DOI	10.1016/j.epsl.2020.116207
	Boron isotope insights into the origin of subduction signatures in continent-continent collision zone volcanism
	Sugden P.J.; Savov I.P.; Agostini S.; Wilson M.; Halama R.; Meliksetian K.
发表日期	2020
ISSN	0012821X
卷号	538
英文摘要	We present the first boron abundance and δ11B data for young (1.5-0 Ma) volcanic rocks formed in an active continent-continent collision zone. The δ11B of post-collisional volcanic rocks (−5 to +2‰) from the Armenian sector of the Arabia-Eurasia collision zone are heavier than mid-ocean ridge basalts (MORB), confirming trace element and isotope evidence for their derivation from a subduction-modified mantle source. Based on the low B/Nb (0.03-0.25 vs 0.2-90 in arc magmas), as well as low Ba/Th and Pb/Ce, this source records a subduction signature which is presently fluid-mobile element depleted relative to most arc settings. The heavier than MORB δ11B of post-collision volcanic rocks argues against derivation of their subduction signature from a stalled slab, which would be expected to produce a component with a lighter than MORB δ11B, due to previous fluid depletion. Instead, the similarity of δ11B in Plio-Pleistocene post-collision to 41 Ma alkaline igneous rocks also from Armenia (and also presented in this study), suggests that the subduction signature is inherited from Mesozoic-Paleogene subduction of Neotethys oceanic slabs. The slab component is then stored in the mantle lithosphere in amphibole, which is consistent with the low [B] in both Armenian volcanic rocks and metasomatic amphibole in mantle xenoliths. Based on trace element and radiogenic isotope systematics, this slab component is thought to be dominated by sediment melts (or supercritical fluids). Previously published δ11B of metasediments suggests a sediment-derived metasomatic agent could produce the B isotope composition observed in Armenian volcanic rocks. The lack of evidence for aqueous fluids preserved over the 40 Myr since initial collision supports observations that this latter component is transitory, while the lifetime of sediment melts/supercritical fluids can be extended to >40 Myr. © 2020 The Authors
关键词	boron isotopes post-collisional volcanism subduction signature
英文关键词	Boron; Effluent treatment; Isotopes; Sediments; Structural geology; Supercritical fluids; Trace elements; Volcanoes; Boron isotopes; Collisional; Continent-continent collisions; Fluid-mobile elements; Isotope compositions; Mid ocean ridge basalts; Radiogenic isotopes; subduction signature; Volcanic rocks; boron isotope; collision zone; igneous geochemistry; mid-ocean ridge basalt; subduction; trace element; volcanic rock; volcanism; Armenia [West Asia]
语种	英语
来源期刊	Earth and Planetary Science Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/202913
作者单位	School of Earth and Environment, University of Leeds, Leeds, West Yorkshire LS2 9JT, United Kingdom; Istituto di Geoscienze e Georisorse, Consiglio Nazionale delle Ricerche, Pisa, 56124, Italy; School of Geography, Geology and the Environment, Keele University, Newcastle-under-Lyme, Staffordshire ST5 5BG, United Kingdom; Institute of Geological Sciences, National Academy of Sciences of Armenia, Yerevan, 0019, Armenia
推荐引用方式 GB/T 7714	Sugden P.J.,Savov I.P.,Agostini S.,et al. Boron isotope insights into the origin of subduction signatures in continent-continent collision zone volcanism[J],2020,538.
APA	Sugden P.J.,Savov I.P.,Agostini S.,Wilson M.,Halama R.,&Meliksetian K..(2020).Boron isotope insights into the origin of subduction signatures in continent-continent collision zone volcanism.Earth and Planetary Science Letters,538.
MLA	Sugden P.J.,et al."Boron isotope insights into the origin of subduction signatures in continent-continent collision zone volcanism".Earth and Planetary Science Letters 538(2020).