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Titolo:
Melt/mantle interaction and melt evolution in the Sartohay high-Al chromite deposits of the Dalabute ophiolite (NW China)
Autore:
Zhou, MF; Robinson, PT; Malpas, J; Aitchison, J; Sun, M; Bai, WJ; Hu, XF;
Indirizzi:
Univ Hong Kong, Dept Earth Sci, Hong Kong, Hong Kong, Peoples R China UnivHong Kong Hong Kong Hong Kong Peoples R China Kong, Peoples R China Dalhousie Univ, Ctr Marine Geol, Halifax, NS B3H 3J5, Canada Dalhousie Univ Halifax NS Canada B3H 3J5 eol, Halifax, NS B3H 3J5, Canada Chinese Acad Geol Sci, Inst Geol, Beijing, Peoples R China Chinese Acad Geol Sci Beijing Peoples R China Beijing, Peoples R China
Titolo Testata:
JOURNAL OF ASIAN EARTH SCIENCES
fascicolo: 4, volume: 19, anno: 2001,
pagine: 517 - 534
SICI:
1367-9120(200106)19:4<517:MIAMEI>2.0.ZU;2-G
Fonte:
ISI
Lingua:
ENG
Soggetto:
WEST JUNGGAR REGION; EAST PACIFIC RISE; PODIFORM CHROMITITES; NORTHWEST CHINA; PRECIOUS-METALS; UPPER-MANTLE; PERIDOTITES; GEOCHEMISTRY; XINJIANG; ORIGIN;
Keywords:
paleozoic ophiolite; high-Al podiform chromite deposit; peridotite; troctolite; melt/mantle interaction; NW China;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
73
Recensione:
Indirizzi per estratti:
Indirizzo: Zhou, MF Univ Hong Kong, Dept Earth Sci, Hong Kong, Hong Kong, Peoples R China Univ Hong Kong Hong Kong Hong Kong Peoples R China ples R China
Citazione:
M.F. Zhou et al., "Melt/mantle interaction and melt evolution in the Sartohay high-Al chromite deposits of the Dalabute ophiolite (NW China)", J ASIAN E S, 19(4), 2001, pp. 517-534

Abstract

The Sartohay block of the Dalabute uphiolite consists chiefly of mantle harzburgite and Iherzulite with minor dunite. These rucks host voluminous chromite deposits with lenticular or vein-like shapes. The podiform chromitites are associated with, and cross-out by, numerous troctolite dykes. Chromite in the chromitites has Al2O3 (23-31 wt%). TiO2 (0.29-0.44 wt%). and Cr2O3contents (< 45 wt%) with Cr#s [100Cr/(Cr + Al)] (< 60), typical of high-Alchromite deposits. The host peridotites in Sartohay have been texturally and geochemically modified by magmas from which the high-Al chromitites and mafic dykes formed. Dunites commonly envelop the podiform chromite bodies and show transitional contacts with the peridotites. Some of the peridotitesand chromitites contain plagioclase that crystallized from impregnated melts. The dunite locally grades into troctolite with increasing plagioclase contents. As a result of melt impregnation, peridotites and dunites show variable Ca and Al contents and LREE enrichment. The parental magma of the chromitites was likely tholeiitic in composition, derived from partial meltingof the asthenospheric mantle in a rising diapir. The interaction between this magma and pre existing lithospheric mantle, composed of depleted lherzolite. would have formed a more silicic. tholeiitic magma from which high-Alchromitites crystallized. During this interaction, harzburgite and dunite were depleted in modal pyroxene and enriched in some incompatible elements (such as Al, Ca and LREE) due to melt impregnation. (C) 2001 Elsevier science Ltd. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 30/05/20 alle ore 21:50:29