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Article: Evolution of the Lüliangshan garnet peridotites in the North Qaidam UHP belt, Northern Tibetan Plateau: Constraints from Re-Os isotopes

TitleEvolution of the Lüliangshan garnet peridotites in the North Qaidam UHP belt, Northern Tibetan Plateau: Constraints from Re-Os isotopes
Authors
KeywordsGarnet peridotite
Mantle refertilisation
North Qaidam
Re-Os isotope
Tibetan Plateau
Issue Date2010
PublisherElsevier BV. The Journal's web site is located at http://www.elsevier.com/locate/lithos
Citation
Lithos, 2010, v. 117 n. 1-4, p. 307-321 How to Cite?
AbstractGarnet peridotite, interlayered with lesser amounts of dunite and olivine websterite and interwoven with garnet pyroxenite dikes, makes up a 0.5km 2 massif near Lüliangshan in the North Qaidam ultrahigh-pressure (UHP) metamorphic belt, Northern Tibetan Plateau. Previous studies have suggested that the garnet peridotites represent Alaskan-style magmatic cumulates or oceanic serpentinites that were subducted to depths of >200km. Re-Os isotopic data provide new constraints on the origin and formation of the peridotites. Most dunites (Mg# 92->95) have high Os contents (2.90-4.25ppb) and low 187Os/ 188Os (minimum 0.1108), while garnet pyroxenites have high 187Os/ 188Os (up to 0.2847) and low Os contents (0.03-1ppb); garnet lherzolites lie between these extremes. The Archean model ages (TRD=2.6Ga, TMA=2.8Ga) of the most refractory dunites represent minimum estimates for the age of the original melt depletion. In an Os- 187Os/ 188Os plot, almost all garnet peridotites fall along two mixing lines: one is defined by mixing between the most refractory dunite and a garnet-rich pyroxenite, and the other by mixing between the dunite and a garnet-poor pyroxenite. The extremely depleted nature of the dunites, the high Ca and Al contents of the lherzolites, the variable enrichment in incompatible elements, and the Re-Os isotopic data suggest that the Lüliangshan garnet peridotites represent a fragment of subcontinental mantle, in which ancient residues after melt extraction (e.g. dunite) were refertilised by mafic melts similar to the garnet pyroxenites. Modelling of the garnet peridotite data suggests that at least some of the metasomatism is Paleoproterozoic in age; Re also may have been introduced into some of the garnet peridotites during the Paleozoic UHP Qaidam orogeny. The Lüliangshan peridotites are interpreted as refertilised Archean subcontinental lithospheric mantle, probably derived from beneath the North China Craton and entrained in the surrounding gneisses during their subduction into the mantle; the garnet peridotite assemblages may have formed during the original refertilisation event, or during the subduction. © 2010 Elsevier B.V.
Persistent Identifierhttp://hdl.handle.net/10722/123867
ISSN
2015 Impact Factor: 3.723
2015 SCImago Journal Rankings: 2.920
ISI Accession Number ID
Funding AgencyGrant Number
Chinese National 973 Program2007CB411307
National Natural Science Foundation of China40972056
40672051
40930316
40873025
ARC
Funding Information:

This research was jointly funded by the Chinese National 973 Program (2007CB411307) and the National Natural Science Foundation of China (grant nos. 40972056, 40672051, 40930316. 40873025) and ARC Discovery and Linkage International Grants (SYO'R and WLG). This is contribution 636 from the ARC National Key Centre for Geochemical Evolution and Metallogeny of Continents (www es.mq.edu.au/GEMOC) Special thanks go to Prof. J.J. Yang working in the Institute of Geology and Geophysics, CAS, Beijing, China and Prof. S G Song working in Peking University, Beijing, China for providing the part samples for this study. A thoughtful review by Hannes Brueckner greatly improved the initial manuscript.

References

 

DC FieldValueLanguage
dc.contributor.authorShi, RDen_HK
dc.contributor.authorGriffin, WLen_HK
dc.contributor.authorO'Reilly, SYen_HK
dc.contributor.authorZhao, GCen_HK
dc.contributor.authorHuang, QSen_HK
dc.contributor.authorLi, Jen_HK
dc.contributor.authorXu, JFen_HK
dc.date.accessioned2010-10-06T08:26:39Z-
dc.date.available2010-10-06T08:26:39Z-
dc.date.issued2010en_HK
dc.identifier.citationLithos, 2010, v. 117 n. 1-4, p. 307-321en_HK
dc.identifier.issn0024-4937en_HK
dc.identifier.urihttp://hdl.handle.net/10722/123867-
dc.description.abstractGarnet peridotite, interlayered with lesser amounts of dunite and olivine websterite and interwoven with garnet pyroxenite dikes, makes up a 0.5km 2 massif near Lüliangshan in the North Qaidam ultrahigh-pressure (UHP) metamorphic belt, Northern Tibetan Plateau. Previous studies have suggested that the garnet peridotites represent Alaskan-style magmatic cumulates or oceanic serpentinites that were subducted to depths of >200km. Re-Os isotopic data provide new constraints on the origin and formation of the peridotites. Most dunites (Mg# 92->95) have high Os contents (2.90-4.25ppb) and low 187Os/ 188Os (minimum 0.1108), while garnet pyroxenites have high 187Os/ 188Os (up to 0.2847) and low Os contents (0.03-1ppb); garnet lherzolites lie between these extremes. The Archean model ages (TRD=2.6Ga, TMA=2.8Ga) of the most refractory dunites represent minimum estimates for the age of the original melt depletion. In an Os- 187Os/ 188Os plot, almost all garnet peridotites fall along two mixing lines: one is defined by mixing between the most refractory dunite and a garnet-rich pyroxenite, and the other by mixing between the dunite and a garnet-poor pyroxenite. The extremely depleted nature of the dunites, the high Ca and Al contents of the lherzolites, the variable enrichment in incompatible elements, and the Re-Os isotopic data suggest that the Lüliangshan garnet peridotites represent a fragment of subcontinental mantle, in which ancient residues after melt extraction (e.g. dunite) were refertilised by mafic melts similar to the garnet pyroxenites. Modelling of the garnet peridotite data suggests that at least some of the metasomatism is Paleoproterozoic in age; Re also may have been introduced into some of the garnet peridotites during the Paleozoic UHP Qaidam orogeny. The Lüliangshan peridotites are interpreted as refertilised Archean subcontinental lithospheric mantle, probably derived from beneath the North China Craton and entrained in the surrounding gneisses during their subduction into the mantle; the garnet peridotite assemblages may have formed during the original refertilisation event, or during the subduction. © 2010 Elsevier B.V.en_HK
dc.languageeng-
dc.publisherElsevier BV. The Journal's web site is located at http://www.elsevier.com/locate/lithosen_HK
dc.relation.ispartofLithosen_HK
dc.rightsLithos. Copyright © Elsevier BV.-
dc.subjectGarnet peridotiteen_HK
dc.subjectMantle refertilisationen_HK
dc.subjectNorth Qaidamen_HK
dc.subjectRe-Os isotopeen_HK
dc.subjectTibetan Plateauen_HK
dc.titleEvolution of the Lüliangshan garnet peridotites in the North Qaidam UHP belt, Northern Tibetan Plateau: Constraints from Re-Os isotopesen_HK
dc.typeArticleen_HK
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=0024-4937&volume=117&issue=1-4&spage=307&epage=321&date=2010&atitle=Genesis+of+the+Lüliangshan+garnet+peridotites+in+the+North+Qaidam+UHP+belt,+Northern+Tibetan+Plateau:+Constraints+from+Re-Os+isotopes-
dc.identifier.emailZhao, GC:gzhao@hkucc.hku.hken_HK
dc.identifier.authorityZhao, GC=rp00842en_HK
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.doi10.1016/j.lithos.2010.03.006en_HK
dc.identifier.scopuseid_2-s2.0-77952668612en_HK
dc.identifier.hkuros175410-
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-77952668612&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume117en_HK
dc.identifier.issue1-4en_HK
dc.identifier.spage307en_HK
dc.identifier.epage321en_HK
dc.identifier.isiWOS:000278731800020-
dc.publisher.placeNetherlandsen_HK
dc.identifier.scopusauthoridShi, RD=7102948255en_HK
dc.identifier.scopusauthoridGriffin, WL=35229299300en_HK
dc.identifier.scopusauthoridO'Reilly, SY=7103188930en_HK
dc.identifier.scopusauthoridZhao, GC=7403296321en_HK
dc.identifier.scopusauthoridHuang, QS=37099724000en_HK
dc.identifier.scopusauthoridLi, J=7410058719en_HK
dc.identifier.scopusauthoridXu, JF=36106568300en_HK
dc.identifier.citeulike6879487-

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