Инд. авторы:	Balykin P.A., Polyakov G.V., Izokh A.E., Hoa T.T., Phuong N.T., Hung T.Q., Petrova T.E.
Заглавие:	Geochemistry and petrogenesis of Permian ultramafic-mafic complexes of the Jinping-Song Da rift (southeastern Asia)
Библ. ссылка:	Balykin P.A., Polyakov G.V., Izokh A.E., Hoa T.T., Phuong N.T., Hung T.Q., Petrova T.E. Geochemistry and petrogenesis of Permian ultramafic-mafic complexes of the Jinping-Song Da rift (southeastern Asia) // Russian Geology and Geophysics. - 2010. - Vol.51. - Iss. 6. - P.611-624. - ISSN 1068-7971. - EISSN 1878-030X.
Идентиф-ры:	DOI: 10.1016/j.rgg.2010.05.003; SCOPUS: 2-s2.0-77953016765;
Реферат:	eng: The Jinping-Song Da rift structure in the Emeishan Large Igneous Province is composed of Permian high- and low-Ti volcanic and volcanoplutonic ultramafic-mafic associations of different compositions and genesis. High-Ti picrites, picrobasalts, basalts, and dolerites are enriched in LREE and depleted in HREE and show low Al2O3/TiO2 ratios (~4), commensurate εNd(T) values (+0.5 to +1.1), and low (Th/Nb)PM ratios similar to those of OIB-enriched mantle source. The established geochemical characteristics evidence that the parental melts of these rocks were generated from garnet lherzolite at the depths of garnet stability (~200 to 400 km). Later, high-Mg low-Ti volcanics (komatiites, komatiitic basalts, and basalts) and associating small peridotite-gabbro massifs and komatiite-basalt dikes were produced as a result of ~20% partial melting of depleted water-poor (≤0.03 wt.% H2O) peridotite substratum from the hottest upper part of mantle plume at relatively shallow depths (100-120 km). The LREE-depleted komatiites and komatiitic basalts are characterized by low (Ce/Yb)CH values, 187Re/188Os = 0.05-1.2, 87Sr/86Sr = 0.704-0.706, positive εNd(T) values (+3 to +8), γOs = -0.5 to +0.9, and strong negative anomalies of Ba, K, and Sr on the spidergrams. The scarcer LREE-enriched komatiites, komatiitic basalts, and basalts vary greatly in chemical composition and values of εNd(t) (+6.4 to -10.2), 87Sr/86Sr (0.706-0.712), and γOs (+14.8 to +56), which is due to the different degrees of crustal contamination of parental magmas. The Rb-Sr isotopic age of basaltic komatiite is 257 ± 24 Ma. The Re-Os age determined by analysis of 12 komatiite samples is 270 ± 21 Ma. These data agree with the age of flood basalts of the Emeishan Large Igneous Province. The komatiite-basalt complex of the Song Da rift is still the only Phanerozoic PGE-Cu-Ni-complex of this composition. The geochemistry of accompanying Cu-Ni-PGE-ores confirms their relationship with komatiite-basaltic magmatism. © 2010.
Ключевые слова:	ultramafic rock; petrogenesis; partial melting; mantle source; mantle plume; mantle chemistry; magmatism; mafic rock; lherzolite; large igneous province; komatiite; crustal contamination; chemical composition; Southeast Asia; picrobasalts; Permian high-Ti picrites; peridotite-gabbro massifs; parental melts; mantle plume; low-Ti komatiites; komatiitic basalts; komatiite-basalt dikes; Jinping-Song Da rift; Emeishan Igneous Province; Cu-Ni-PGE deposits and ore occurrences; and dolerites; and basalts; basalt;
Издано:	2010
Физ. хар-ка:	с.611-624