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Article: Geochemical significance of a garnet lherzolite from the Dahongshan kimberlite, Yangtze Craton, southern China

TitleGeochemical significance of a garnet lherzolite from the Dahongshan kimberlite, Yangtze Craton, southern China
Authors
Issue Date2001
PublisherBusiness Center for Academic Societies Japan.
Citation
Geochemical Journal, 2001, v. 35 n. 5, p. 315-331 How to Cite?
AbstractThe Dahongshan kimberlite field in Hubei Province, China, is situated in the northern margin of the Proterozoic Yangtze Craton. The kimberlites crupted in the Paleozoic (ca. 326 Ma), some of which are associated with barren lamproites. An unusually fresh garnet lherzolite collected from this kimberlite field provides an opportunity to directly study the nature of the Paleozoic lithospheric mantle beneath the Yangtze Craton. The lherzolite is moderately depleted in major element compositions (2.66wt% Al 2o 3, 2.82wt% Cao, and 90.9 Mg#), with a forsterite content in olivine around 90.5%. The rare earth element characteristics of the whole rock [(La/Sm) N=13 and (Eu/Yb) N=0.48] and of the constituent minerals such as clinopyroxene [(La/Yb) N = 61] reveal that at least two processes were recorded in the lherzolite: depletion followed by enrichment. Depletion process was derived from low degree of partial melting, as demonstrated by relatively high NiO contents (0.50%) in olivines and PPGE-enriched mantle-normalized PGE pattern of the whole rock. The enrichments in LREE and LILE are attributed to melt infiltration that must be an event prior to the kimberlite cruption as constrained by trace element and Sr-Nd isotopic data. The Rb-Sr and Sm-Nd data constrained an age of about 510 Ma, which is much older than the age of kimberlite cruption, but consistent with the eruption time of diamond-bearing lamproites on the centre of the Craton. The stable Gt-Opx-Cpx mineral assemblage gives a T-P estimation of 1042°C and 34 kbar, corresponding to 110 km depth, well within the graphite stability field. The geotherm inferred from this lherzolite was much higher than the typical cratonic geotherm (40 mW/m 2), but still lower than the oceanic geotherm. Thus, our study and previous data demonstrate that the lithospheric mantle beneath the Yangtze craton was less depleted and was hotter in Paleozoic than the lithospheric mantle beneath typical old Cratons. i.e., the Kaapvaal, the Siberia, and the North China.
Persistent Identifierhttp://hdl.handle.net/10722/72805
ISSN
2015 Impact Factor: 0.621
2015 SCImago Journal Rankings: 0.837
References

 

DC FieldValueLanguage
dc.contributor.authorZhang, HFen_HK
dc.contributor.authorSun, Men_HK
dc.contributor.authorLu, FXen_HK
dc.contributor.authorZhou, XHen_HK
dc.contributor.authorZhou, MFen_HK
dc.contributor.authorLiu, YSen_HK
dc.contributor.authorZhang, GHen_HK
dc.date.accessioned2010-09-06T06:45:16Z-
dc.date.available2010-09-06T06:45:16Z-
dc.date.issued2001en_HK
dc.identifier.citationGeochemical Journal, 2001, v. 35 n. 5, p. 315-331en_HK
dc.identifier.issn0016-7002en_HK
dc.identifier.urihttp://hdl.handle.net/10722/72805-
dc.description.abstractThe Dahongshan kimberlite field in Hubei Province, China, is situated in the northern margin of the Proterozoic Yangtze Craton. The kimberlites crupted in the Paleozoic (ca. 326 Ma), some of which are associated with barren lamproites. An unusually fresh garnet lherzolite collected from this kimberlite field provides an opportunity to directly study the nature of the Paleozoic lithospheric mantle beneath the Yangtze Craton. The lherzolite is moderately depleted in major element compositions (2.66wt% Al 2o 3, 2.82wt% Cao, and 90.9 Mg#), with a forsterite content in olivine around 90.5%. The rare earth element characteristics of the whole rock [(La/Sm) N=13 and (Eu/Yb) N=0.48] and of the constituent minerals such as clinopyroxene [(La/Yb) N = 61] reveal that at least two processes were recorded in the lherzolite: depletion followed by enrichment. Depletion process was derived from low degree of partial melting, as demonstrated by relatively high NiO contents (0.50%) in olivines and PPGE-enriched mantle-normalized PGE pattern of the whole rock. The enrichments in LREE and LILE are attributed to melt infiltration that must be an event prior to the kimberlite cruption as constrained by trace element and Sr-Nd isotopic data. The Rb-Sr and Sm-Nd data constrained an age of about 510 Ma, which is much older than the age of kimberlite cruption, but consistent with the eruption time of diamond-bearing lamproites on the centre of the Craton. The stable Gt-Opx-Cpx mineral assemblage gives a T-P estimation of 1042°C and 34 kbar, corresponding to 110 km depth, well within the graphite stability field. The geotherm inferred from this lherzolite was much higher than the typical cratonic geotherm (40 mW/m 2), but still lower than the oceanic geotherm. Thus, our study and previous data demonstrate that the lithospheric mantle beneath the Yangtze craton was less depleted and was hotter in Paleozoic than the lithospheric mantle beneath typical old Cratons. i.e., the Kaapvaal, the Siberia, and the North China.en_HK
dc.languageengen_HK
dc.publisherBusiness Center for Academic Societies Japan.en_HK
dc.relation.ispartofGeochemical Journalen_HK
dc.titleGeochemical significance of a garnet lherzolite from the Dahongshan kimberlite, Yangtze Craton, southern Chinaen_HK
dc.typeArticleen_HK
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=0016-7002&volume=35&spage=315&epage=331&date=2001&atitle=Geochemical+significance+of+a+garnet+lherzolite+from+the+Dahongshan+kimberlite,+Yangtze+Craton,+southern+Chinaen_HK
dc.identifier.emailSun, M:minsun@hku.hken_HK
dc.identifier.emailZhou, MF:mfzhou@hkucc.hku.hken_HK
dc.identifier.authoritySun, M=rp00780en_HK
dc.identifier.authorityZhou, MF=rp00844en_HK
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.scopuseid_2-s2.0-0035150073en_HK
dc.identifier.hkuros72246en_HK
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-0035150073&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume35en_HK
dc.identifier.issue5en_HK
dc.identifier.spage315en_HK
dc.identifier.epage331en_HK
dc.publisher.placeJapanen_HK
dc.identifier.scopusauthoridZhang, HF=14625789700en_HK
dc.identifier.scopusauthoridSun, M=25932315800en_HK
dc.identifier.scopusauthoridLu, FX=54395850100en_HK
dc.identifier.scopusauthoridZhou, XH=7410089813en_HK
dc.identifier.scopusauthoridZhou, MF=7403506005en_HK
dc.identifier.scopusauthoridLiu, YS=26651938100en_HK
dc.identifier.scopusauthoridZhang, GH=7405273736en_HK

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