File Download

There are no files associated with this item.

  Links for fulltext
     (May Require Subscription)
Supplementary

Article: Accretionary orogenesis of the Chinese Altai: Insights from Paleozoic granitoids

TitleAccretionary orogenesis of the Chinese Altai: Insights from Paleozoic granitoids
Authors
KeywordsAccretionary orogenesis
Active continental margin
CAOB
Chinese Altai
Dehydration-melting
Granitoids
Issue Date2007
PublisherElsevier BV. The Journal's web site is located at http://www.elsevier.com/locate/chemgeo
Citation
Chemical Geology, 2007, v. 242 n. 1-2, p. 22-39 How to Cite?
AbstractZircon U-Pb dating and whole-rock major oxide, trace element and Nd-Sr isotope compositions have been determined for four representative granitic intrusions in the SW Chinese Altai, in order to understand the orogenesis and history of crustal growth in the Central Asian Orogenic Belt (CAOB). The Ashile and Halatas bodies are relatively small intrusions formed in the Late Carboniferous (318 ± 6 Ma) and Permian (267 ± 4 Ma), respectively. The larger Tarlang (TB) and Keketuohai Batholiths (KB) have magmatic ages of 359 to 412 Ma. The granitoids consist chiefly of tonalite, granodiorite and granite, and are metaluminous to weakly peraluminous in composition (ASI = 0.8-1.1). The Ashile Pluton is characterized by relatively high MgO (2.73-3.54 wt.%) and Sr (395-456 ppm) contents, with low K 2O/Na 2O ratios (0.31-0.42) and mantle-like Nd-Sr isotopic compositions (εNd T = + 2.85 to+ 3.26; initial 87Sr/ 86Sr = 0.7047-0.7051). It probably formed by fractional crystallization of a mantle-derived magma, with limited assimilation of old crustal material. The other intrusions have near-zero or negative εNd T values (- 0.67 to- 4.41) and higher Sr isotopic compositions (initial 87Sr/ 86Sr = 0.7067-0.7092), indicating a mixture of juvenile and old components in their genesis. These intrusions are characterized by relatively low K, Rb, Cs contents and low Rb/Sr ratios (mostly < 0.6), and generally exhibit moderate to high heavy rare earth element (HREE) concentrations (Yb N = 8-26) and weak HREE fractionation (Dy/Yb N < 1.5), with or without negative europium anomalies (Eu/Eu * = 0.5-1.0). These characteristics are consistent with an origin by dehydration melting of a hornblende-bearing, mid-crustal source (above the garnet stability field) dominated by mafic to intermediate rocks. This suggests that the deep crust of the Chinese Altai may contain a considerable proportion of juvenile material. Mantle-derived magmatism, probably in an active extensional continental margin setting, played an important role in the formation of the Chinese Altai, acting not only as a heat source for crustal melting but as a source of juvenile components. The relatively small volumes and distinct geochemical compositions of the Ashile and Halatas Plutons may imply a substantial change in the geodynamic setting in the late Paleozoic. © 2007 Elsevier B.V. All rights reserved.
Persistent Identifierhttp://hdl.handle.net/10722/72535
ISSN
2015 Impact Factor: 3.482
2015 SCImago Journal Rankings: 2.346
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorYuan, Cen_HK
dc.contributor.authorSun, Men_HK
dc.contributor.authorXiao, Wen_HK
dc.contributor.authorLi, Xen_HK
dc.contributor.authorChen, Hen_HK
dc.contributor.authorLin, Sen_HK
dc.contributor.authorXia, Xen_HK
dc.contributor.authorLong, Xen_HK
dc.date.accessioned2010-09-06T06:42:45Z-
dc.date.available2010-09-06T06:42:45Z-
dc.date.issued2007en_HK
dc.identifier.citationChemical Geology, 2007, v. 242 n. 1-2, p. 22-39en_HK
dc.identifier.issn0009-2541en_HK
dc.identifier.urihttp://hdl.handle.net/10722/72535-
dc.description.abstractZircon U-Pb dating and whole-rock major oxide, trace element and Nd-Sr isotope compositions have been determined for four representative granitic intrusions in the SW Chinese Altai, in order to understand the orogenesis and history of crustal growth in the Central Asian Orogenic Belt (CAOB). The Ashile and Halatas bodies are relatively small intrusions formed in the Late Carboniferous (318 ± 6 Ma) and Permian (267 ± 4 Ma), respectively. The larger Tarlang (TB) and Keketuohai Batholiths (KB) have magmatic ages of 359 to 412 Ma. The granitoids consist chiefly of tonalite, granodiorite and granite, and are metaluminous to weakly peraluminous in composition (ASI = 0.8-1.1). The Ashile Pluton is characterized by relatively high MgO (2.73-3.54 wt.%) and Sr (395-456 ppm) contents, with low K 2O/Na 2O ratios (0.31-0.42) and mantle-like Nd-Sr isotopic compositions (εNd T = + 2.85 to+ 3.26; initial 87Sr/ 86Sr = 0.7047-0.7051). It probably formed by fractional crystallization of a mantle-derived magma, with limited assimilation of old crustal material. The other intrusions have near-zero or negative εNd T values (- 0.67 to- 4.41) and higher Sr isotopic compositions (initial 87Sr/ 86Sr = 0.7067-0.7092), indicating a mixture of juvenile and old components in their genesis. These intrusions are characterized by relatively low K, Rb, Cs contents and low Rb/Sr ratios (mostly < 0.6), and generally exhibit moderate to high heavy rare earth element (HREE) concentrations (Yb N = 8-26) and weak HREE fractionation (Dy/Yb N < 1.5), with or without negative europium anomalies (Eu/Eu * = 0.5-1.0). These characteristics are consistent with an origin by dehydration melting of a hornblende-bearing, mid-crustal source (above the garnet stability field) dominated by mafic to intermediate rocks. This suggests that the deep crust of the Chinese Altai may contain a considerable proportion of juvenile material. Mantle-derived magmatism, probably in an active extensional continental margin setting, played an important role in the formation of the Chinese Altai, acting not only as a heat source for crustal melting but as a source of juvenile components. The relatively small volumes and distinct geochemical compositions of the Ashile and Halatas Plutons may imply a substantial change in the geodynamic setting in the late Paleozoic. © 2007 Elsevier B.V. All rights reserved.en_HK
dc.languageengen_HK
dc.publisherElsevier BV. The Journal's web site is located at http://www.elsevier.com/locate/chemgeoen_HK
dc.relation.ispartofChemical Geologyen_HK
dc.rightsChemical Geology. Copyright © Elsevier BV.en_HK
dc.subjectAccretionary orogenesisen_HK
dc.subjectActive continental marginen_HK
dc.subjectCAOBen_HK
dc.subjectChinese Altaien_HK
dc.subjectDehydration-meltingen_HK
dc.subjectGranitoidsen_HK
dc.titleAccretionary orogenesis of the Chinese Altai: Insights from Paleozoic granitoidsen_HK
dc.typeArticleen_HK
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=0009-2541&volume=242&spage=22&epage=39&date=2007&atitle=Accretionary+orogenesis+of+the+Chinese+Altai:+Insights+from+Paleozoic+granitoidsen_HK
dc.identifier.emailSun, M: minsun@hku.hken_HK
dc.identifier.emailXia, X: xpxia@hotmail.comen_HK
dc.identifier.authoritySun, M=rp00780en_HK
dc.identifier.authorityXia, X=rp00815en_HK
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.doi10.1016/j.chemgeo.2007.02.013en_HK
dc.identifier.scopuseid_2-s2.0-34250701722en_HK
dc.identifier.hkuros136516en_HK
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-34250701722&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume242en_HK
dc.identifier.issue1-2en_HK
dc.identifier.spage22en_HK
dc.identifier.epage39en_HK
dc.identifier.isiWOS:000248433400002-
dc.publisher.placeNetherlandsen_HK
dc.identifier.scopusauthoridYuan, C=35241599200en_HK
dc.identifier.scopusauthoridSun, M=25932315800en_HK
dc.identifier.scopusauthoridXiao, W=7202456615en_HK
dc.identifier.scopusauthoridLi, X=49261023700en_HK
dc.identifier.scopusauthoridChen, H=35331626500en_HK
dc.identifier.scopusauthoridLin, S=7407611598en_HK
dc.identifier.scopusauthoridXia, X=35241486400en_HK
dc.identifier.scopusauthoridLong, X=14012199100en_HK

Export via OAI-PMH Interface in XML Formats


OR


Export to Other Non-XML Formats