Geochemistry of basaltic lavas from the southern Lau Basin: input of compositionally variable subduction components

doi:10.1080/00206814.2012.664031

	Geochemistry of basaltic lavas from the southern Lau Basin: input of compositionally variable subduction components
	Yan, Quanshu 1,2; Castillo, Paterno R.2; Shi, Xuefa 1
刊名	INTERNATIONAL GEOLOGY REVIEW
	2012
卷号	54 期号:12 页码:1456-1474
关键词	Eastern Lau Spreading Centre Valu Fa Ridge supra-subduction zone back-arc basin lavas southern Lau Basin
ISSN号	0020-6814
DOI	10.1080/00206814.2012.664031
英文摘要	We present new major element, trace element, and Sr-Nd-Pb isotope data for 18 basaltic lavas and six glasses collected in situ from the Eastern Lau Spreading Centre (ELSC) and the Valu Fa Ridge (VFR). All lava samples are aphanitic and contain rare plagioclase and clinopyroxene microlites and microphenocrysts. The rocks are sub-alkaline and range from basalt and basaltic andesite to more differentiated andesite. In terms of trace element compositions, the samples are transitional between typical normal mid-ocean ridge basalt (MORB) and island arc basalt. Samples from the VFR have higher large ion lithophile element/high field strength element ratios (e. g. Ba/Nb) than the ELSC samples. VFR and ELSC Sr-Nd isotopic compositions plot between Indian MORB and Tonga arc lavas, but VFR samples have higher Sr-87/Sr-86 for a given Nd-143/Nd-144 ratio than ELSC analogues. The Pb isotopic composition of ELSC lavas is more Indian MORB-like, whereas that of VFR lavas is more Pacific MORB-like. Our new data, combined with literature data for the Central Lau Spreading Centre, indicate that the mantle beneath the ELSC and VFR spreading centres was originally of Pacific type in composition, but was displaced by Indian-type mantle as rifting propagated to the south. The mantle beneath the spreading centres also was variably affected by subduction-induced metasomatism, mainly by fluids released from the altered, subducting oceanic crust; the influence of these components is best seen in VFR lavas. To a first approximation, the effects of underflow on the composition and degree of partial melting of the mantle source of Lau spreading centre lavas inversely correlate with distance of the spreading centres from the Tonga arc. Superimposed on this general process, however, are the effects of the local geographic contrasts in the composition of subduction components. The latter have been transferred mainly by dehydration-generated fluids into the mantle beneath the Tonga supra-subduction zone.
资助项目	China Postdoctoral Science Foundation[200904501348] ; China Postdoctoral Science Foundation[201104616]
WOS关键词	BACK-ARC BASIN ; TONGA-KERMADEC ARC ; DEPLETED MANTLE WEDGE ; TRACE-ELEMENT ; WESTERN PACIFIC ; CRUSTAL THICKNESS ; ISOTOPIC EVIDENCE ; SPREADING CENTER ; SW PACIFIC ; ISLAND-ARC
WOS研究方向	Geology
语种	英语
出版者	TAYLOR & FRANCIS INC
WOS记录号	WOS:000306166300007
内容类型	期刊论文
源URL	[http://ir.fio.com.cn:8080/handle/2SI8HI0U/26841]
专题	自然资源部第一海洋研究所
通讯作者	Shi, Xuefa
作者单位	1.State Ocean Adm, Inst Oceanog 1, Key Lab Marine Sedimentary & Environm Geol, Qingdao 266061, Peoples R China 2.Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA
推荐引用方式 GB/T 7714	Yan, Quanshu,Castillo, Paterno R.,Shi, Xuefa. Geochemistry of basaltic lavas from the southern Lau Basin: input of compositionally variable subduction components[J]. INTERNATIONAL GEOLOGY REVIEW,2012,54(12):1456-1474.
APA	Yan, Quanshu,Castillo, Paterno R.,&Shi, Xuefa.(2012).Geochemistry of basaltic lavas from the southern Lau Basin: input of compositionally variable subduction components.INTERNATIONAL GEOLOGY REVIEW,54(12),1456-1474.
MLA	Yan, Quanshu,et al."Geochemistry of basaltic lavas from the southern Lau Basin: input of compositionally variable subduction components".INTERNATIONAL GEOLOGY REVIEW 54.12(2012):1456-1474.