File Download

There are no files associated with this item.

  Links for fulltext
     (May Require Subscription)
Supplementary

Article: Late Ordovician to early Devonian adakites and Nb-enriched basalts in the Liuyuan area, Beishan, NW China: Implications for early Paleozoic slab-melting and crustal growth in the southern Altaids

TitleLate Ordovician to early Devonian adakites and Nb-enriched basalts in the Liuyuan area, Beishan, NW China: Implications for early Paleozoic slab-melting and crustal growth in the southern Altaids
Authors
KeywordsAdakites
Altaids
Beishan
Crustal Growth
Geochemistry
Geochronology
Nb-Enriched Basalts
Issue Date2012
PublisherElsevier BV. The Journal's web site is located at http://www.elsevier.com/locate/jcr
Citation
Gondwana Research, 2012, v. 22 n. 2, p. 534-553 How to Cite?
AbstractWe report newly-defined Nb-enriched basalts, adakites and dacites from the Beishan, NW China of the southern Altaids based on field, geochemical, isotopic and geochronology studies. Two phases of adakites (adakite-I and adakite-II) have been defined, which are calc-alkaline, and characterized by high Na 2O/K 2O ratios (1.49-1.71 and 2.32-3.64) and Sr contents (494-1213 ppm and 325-494 ppm), negligible to positive Eu anomalies, strong depletion of HREE (e.g., Yb = 0.48-0.93 ppm and 0.50-0.99 ppm) and Y (6.87-9.80 ppm and 6.02-10.30 ppm), and enriched in Rb, Sr, Ba, K and depleted Nb and Ti. They are characterized by relatively low ε Nd(t) values (- 0.8 to - 0.9 and + 0.6 to + 3.8) and relatively constant high ( 87Sr/ 86Sr) i ratios (0.70635-0.70636 and 0.70583-0.70651). The zircons of adakite-I have relatively low ε Hf(t)(- 0.8 to + 2.7). The Nb-enriched basalts are sodium-rich (N 2O/K 2O = 1.31-4.44), with higher TiO 2, P 2O 5, Zr and Nb contents and (Nb/Th) PM, (Nb/La) PM and Nb/U ratios than typical arc basalts. They are relatively enriched in Rb, Ba, U, Pb and K, depleted in Nb, and minor negative to positive Ba, Zr, Sr and Ti. They have low positive ε Nd(t) (+ 0.9 to + 2.3) and relatively high ( 87Sr/ 86Sr) i (0.70556-0.70691) ratios. The dacites are typical arc magmas, with moderately enriched LILE, distinctly negative Eu, Nb, Sr and Ti anomalies. They have positive ε Nd(t) (+ 2.2) and relatively high ( 87Sr/ 86Sr) i (0.70786). We argue that the Liuyuan adakites were most probably related to the melting of young/hot subducted crust of the Paleo-Asian Ocean, which included tectonically-subducted radiogenic crustal material and/or inheritance from highly radiogenic oceanic crust (e.g. OIB). The Nb-enriched basalts likely resulted from mantle wedge peridotites metasomatized by adakites and/or further changed by components other than adakites (e.g., minor slab-derived fluids). Based on own zircon SIMS U-Pb dating of these key rock types, we further propose that from the late Ordovician to early Devonian, large volumes of magma consisting of late Ordovician Nb-enriched basalts (451 Ma) and dacites (442 Ma), late Silurian adakite-I (424 Ma), early Devonian adakite-II (374 Ma) and I-S-A-type granites (436 Ma-380 Ma), developed in the southern Altaids. Together with other geochronological data from the literature, we conclude that subducted oceanic slab-melting was frequent from 470 Ma to 370 Ma. Our results suggest that frequent hot (and/or young) oceanic crustal subduction and slab-melting were important mechanisms in the accretionary growth of the Southern Altaids. © 2011 International Association for Gondwana Research.
Persistent Identifierhttp://hdl.handle.net/10722/151317
ISSN
2014 Impact Factor: 8.235
2014 SCImago Journal Rankings: 4.259
ISI Accession Number ID

 

DC FieldValueLanguage
dc.contributor.authorMao, Qen_US
dc.contributor.authorXiao, Wen_US
dc.contributor.authorFang, Ten_US
dc.contributor.authorWang, Jen_US
dc.contributor.authorHan, Cen_US
dc.contributor.authorSun, Men_US
dc.contributor.authorYuan, Cen_US
dc.date.accessioned2012-06-26T06:20:33Z-
dc.date.available2012-06-26T06:20:33Z-
dc.date.issued2012en_US
dc.identifier.citationGondwana Research, 2012, v. 22 n. 2, p. 534-553en_US
dc.identifier.issn1342-937Xen_US
dc.identifier.urihttp://hdl.handle.net/10722/151317-
dc.description.abstractWe report newly-defined Nb-enriched basalts, adakites and dacites from the Beishan, NW China of the southern Altaids based on field, geochemical, isotopic and geochronology studies. Two phases of adakites (adakite-I and adakite-II) have been defined, which are calc-alkaline, and characterized by high Na 2O/K 2O ratios (1.49-1.71 and 2.32-3.64) and Sr contents (494-1213 ppm and 325-494 ppm), negligible to positive Eu anomalies, strong depletion of HREE (e.g., Yb = 0.48-0.93 ppm and 0.50-0.99 ppm) and Y (6.87-9.80 ppm and 6.02-10.30 ppm), and enriched in Rb, Sr, Ba, K and depleted Nb and Ti. They are characterized by relatively low ε Nd(t) values (- 0.8 to - 0.9 and + 0.6 to + 3.8) and relatively constant high ( 87Sr/ 86Sr) i ratios (0.70635-0.70636 and 0.70583-0.70651). The zircons of adakite-I have relatively low ε Hf(t)(- 0.8 to + 2.7). The Nb-enriched basalts are sodium-rich (N 2O/K 2O = 1.31-4.44), with higher TiO 2, P 2O 5, Zr and Nb contents and (Nb/Th) PM, (Nb/La) PM and Nb/U ratios than typical arc basalts. They are relatively enriched in Rb, Ba, U, Pb and K, depleted in Nb, and minor negative to positive Ba, Zr, Sr and Ti. They have low positive ε Nd(t) (+ 0.9 to + 2.3) and relatively high ( 87Sr/ 86Sr) i (0.70556-0.70691) ratios. The dacites are typical arc magmas, with moderately enriched LILE, distinctly negative Eu, Nb, Sr and Ti anomalies. They have positive ε Nd(t) (+ 2.2) and relatively high ( 87Sr/ 86Sr) i (0.70786). We argue that the Liuyuan adakites were most probably related to the melting of young/hot subducted crust of the Paleo-Asian Ocean, which included tectonically-subducted radiogenic crustal material and/or inheritance from highly radiogenic oceanic crust (e.g. OIB). The Nb-enriched basalts likely resulted from mantle wedge peridotites metasomatized by adakites and/or further changed by components other than adakites (e.g., minor slab-derived fluids). Based on own zircon SIMS U-Pb dating of these key rock types, we further propose that from the late Ordovician to early Devonian, large volumes of magma consisting of late Ordovician Nb-enriched basalts (451 Ma) and dacites (442 Ma), late Silurian adakite-I (424 Ma), early Devonian adakite-II (374 Ma) and I-S-A-type granites (436 Ma-380 Ma), developed in the southern Altaids. Together with other geochronological data from the literature, we conclude that subducted oceanic slab-melting was frequent from 470 Ma to 370 Ma. Our results suggest that frequent hot (and/or young) oceanic crustal subduction and slab-melting were important mechanisms in the accretionary growth of the Southern Altaids. © 2011 International Association for Gondwana Research.en_US
dc.languageengen_US
dc.publisherElsevier BV. The Journal's web site is located at http://www.elsevier.com/locate/jcren_US
dc.relation.ispartofGondwana Researchen_US
dc.subjectAdakitesen_US
dc.subjectAltaidsen_US
dc.subjectBeishanen_US
dc.subjectCrustal Growthen_US
dc.subjectGeochemistryen_US
dc.subjectGeochronologyen_US
dc.subjectNb-Enriched Basaltsen_US
dc.titleLate Ordovician to early Devonian adakites and Nb-enriched basalts in the Liuyuan area, Beishan, NW China: Implications for early Paleozoic slab-melting and crustal growth in the southern Altaidsen_US
dc.typeArticleen_US
dc.identifier.emailSun, M:minsun@hku.hken_US
dc.identifier.authoritySun, M=rp00780en_US
dc.description.naturelink_to_subscribed_fulltexten_US
dc.identifier.doi10.1016/j.gr.2011.06.006en_US
dc.identifier.scopuseid_2-s2.0-84863877922en_US
dc.identifier.hkuros219581-
dc.identifier.isiWOS:000307602000014-
dc.publisher.placeNetherlandsen_US
dc.identifier.scopusauthoridMao, Q=35916504900en_US
dc.identifier.scopusauthoridXiao, W=7202456615en_US
dc.identifier.scopusauthoridFang, T=7201676404en_US
dc.identifier.scopusauthoridWang, J=43661827200en_US
dc.identifier.scopusauthoridHan, C=35794513200en_US
dc.identifier.scopusauthoridSun, M=25932315800en_US
dc.identifier.scopusauthoridYuan, C=35241599200en_US

Export via OAI-PMH Interface in XML Formats


OR


Export to Other Non-XML Formats