Accretionary wedge harzburgite serpentinization and rodingitization constrained by perovskite U/Pb SIMS age, trace elements and Sm/Nd isotopes: Case study from the Western Carpathians, Slovakia

doi:10.1016/j.lithos.2014.06.001

	Accretionary wedge harzburgite serpentinization and rodingitization constrained by perovskite U/Pb SIMS age, trace elements and Sm/Nd isotopes: Case study from the Western Carpathians, Slovakia
	Li, Xian-Hua 1; Putis, Marian 2; Yang, Yue-Heng 1; Koppa, Matus 2; Dyda, Marian 2
刊名	LITHOS
	2014-09-15
卷号	205 页码:1-14
关键词	Perovskite U/Pb SIMS age Serpentinization Rodingitization Accretionary wedge Western Carpathians
ISSN号	0024-4937
DOI	10.1016/j.lithos.2014.06.001
文献子类	Article
英文摘要	Perovskite-bearing harzburgites occur in a "melange" type blueschist-bearing accretionary wedge complex of the Inner Western Carpathians Meliata Unit in Slovakia. Although dark rounded, slightly hydrated relic "cores" of harzburgite boulders are perovskite-free, perovskite (Pry) occurrence in the surrounding serpentinites and rodingites enabled dating of hydration, resulting in two metamorphic-metasomatic Pry generations. Perovskite (1) grows parallel to relic clinopyroxene exsolution lamellae or forms randomly oriented grain clusters in serpentinized orthopyroxene (Opx(1)) porphyroclasts, often accompanied by tiny andradite lamellae clusters, or it is partly replaced by Ti-andradite. Perovskite crystallization indicates evolving rodingitization fluids pervading the boundary between the harzburgite "cores" and Pry-free serpentinite. This strictly limited occurrence of Pry (1) within a 1 to 20-cm across-zone implies slightly postponed Pry crystallization to serpentinization by LREE(Ce,La), Ca2+, Ti/Fe3+-enriched aqueous fluids. A grain scale metasomatic mechanism partitioned Ca and Ti from the host orthopyroxene porphyroclasts, spinel (Ti) and grain-boundary pervasive fluids to Prv. In contrast Pry (2) occurs in a 1 to 3 cm across chlorite-rich blackwall zone between hosting serpentinite and rodingite veins, thus indicating channelled rodingitization fluid flow and accompanying hydraulic fracturing. Here, Prv (2) is ingrown by chlorite and apatite. Part of this Pry (2) formed in a rodingite vein mineral assemblage composed of diopside, andradite, vesuvianite, epidote/zoisite, apatite and chlorite. Both perovskite 1 and 2 are replaced by pyrophanite along the grain rims and interiors; most likely via fluid-aided coupled dissolution-reprecipitation at increased Si-Fe-Mn-Al element solubility in rodingitization fluids pervading serpentinized harzburgite. Both Pry generations, especially Pry (2), can be partly to almost totally replaced by (Ti-) Adr. Overgrowths of spinel by andradite are occasionally observed in contact zones between the serpentinites and rodingites. LA-ICP-MS study revealed strong depletion in LREE from Pry (1) to Pry (2), and a more typically positive Eu anomaly for Pry (2). Our spider diagram depicts relative enrichment in U, Nb, La, Ce, Pr, Nd, and decreased Rb, Ba, Th, Ta, Pb, Sr, Zr in both Pry generations. The U/Pb SIMS concordia ages of Pry (1) from 3 samples range from 137 +/- 1 Ma to 135 +/- 1 Ma, with a mean of 135.6 +/- 0.58 Ma, while Pry (2) was dated at 133.7 +/- 5.4 Ma. Such negligible age differences imply a relatively short-lived rodingitization event responsible for crystallization of both Prv generations. The Nd-143/Nd-144 mean value of Pry (1) is 0.512153 +/- 0.000017 by LA-MC-ICP-MS, thus corresponding to the initial epsilon(Nd)(t = 135) = -8.2 +/- 0.4 (math's mean). This suggests that the subducted and dehydrated continental crust was the main source of the interactive fluids which initiated serpentinization and rodingitization in the Neotethyan Meliatic accretionary wedge following closure of the Meliata-Hallstatt Triassic to Jurassic oceanic back-arc basin and the high-pressure metamorphism dated at ca. 160-150 Ma by Ar-40/Ar-39. (C) 2014 Elsevier B.V. All rights reserved.
WOS关键词	PLASMA-MASS SPECTROMETRY ; U-PB AGE ; MELIATA UNIT ; TECTONOTHERMAL EVOLUTION ; COMPOSITIONAL VARIATION ; SUPRA-SUBDUCTION ; SOMERSET ISLAND ; OROGENIC WEDGE ; SOUTH-AFRICA ; MC-ICPMS
WOS研究方向	Geochemistry & Geophysics ; Mineralogy
语种	英语
出版者	ELSEVIER SCIENCE BV
WOS记录号	WOS:000342524800001
资助机构	NSFC(41273070) ; NSFC(41273070) ; NSFC(41273070) ; NSFC(41273070) ; (APVV-0081-10) ; (APVV-0081-10) ; (APVV-0081-10) ; (APVV-0081-10) ; (VEGA-1/0255/11) ; (VEGA-1/0255/11) ; (VEGA-1/0255/11) ; (VEGA-1/0255/11) ; NSFC(41273070) ; NSFC(41273070) ; NSFC(41273070) ; NSFC(41273070) ; (APVV-0081-10) ; (APVV-0081-10) ; (APVV-0081-10) ; (APVV-0081-10) ; (VEGA-1/0255/11) ; (VEGA-1/0255/11) ; (VEGA-1/0255/11) ; (VEGA-1/0255/11) ; NSFC(41273070) ; NSFC(41273070) ; NSFC(41273070) ; NSFC(41273070) ; (APVV-0081-10) ; (APVV-0081-10) ; (APVV-0081-10) ; (APVV-0081-10) ; (VEGA-1/0255/11) ; (VEGA-1/0255/11) ; (VEGA-1/0255/11) ; (VEGA-1/0255/11) ; NSFC(41273070) ; NSFC(41273070) ; NSFC(41273070) ; NSFC(41273070) ; (APVV-0081-10) ; (APVV-0081-10) ; (APVV-0081-10) ; (APVV-0081-10) ; (VEGA-1/0255/11) ; (VEGA-1/0255/11) ; (VEGA-1/0255/11) ; (VEGA-1/0255/11)
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/84985]
专题	中国科学院地质与地球物理研究所
通讯作者	Putis, Marian
作者单位	1.Chinese Acad Sci, Inst Geol & Geophys, State Key Lab Lithospher Evolut, Beijing 100029, Peoples R China 2.Comenius Univ, Fac Nat Sci, Dept Mineral & Petr, Bratislava 84215, Slovakia
推荐引用方式 GB/T 7714	Li, Xian-Hua,Putis, Marian,Yang, Yue-Heng,et al. Accretionary wedge harzburgite serpentinization and rodingitization constrained by perovskite U/Pb SIMS age, trace elements and Sm/Nd isotopes: Case study from the Western Carpathians, Slovakia[J]. LITHOS,2014,205:1-14.
APA	Li, Xian-Hua,Putis, Marian,Yang, Yue-Heng,Koppa, Matus,&Dyda, Marian.(2014).Accretionary wedge harzburgite serpentinization and rodingitization constrained by perovskite U/Pb SIMS age, trace elements and Sm/Nd isotopes: Case study from the Western Carpathians, Slovakia.LITHOS,205,1-14.
MLA	Li, Xian-Hua,et al."Accretionary wedge harzburgite serpentinization and rodingitization constrained by perovskite U/Pb SIMS age, trace elements and Sm/Nd isotopes: Case study from the Western Carpathians, Slovakia".LITHOS 205(2014):1-14.