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标题：Petrogenesis and mantle source characteristics of Triassic alkaline basaltic rocks of North Kamarbon, Northern Central Alborz, Iran
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作者：Roghieh Doroozi ; Carmela Vaccaro ; Fariborz Masoudi 等
期刊名称：Solid Earth Sciences
印刷版ISSN：2451-912X
电子版ISSN：2451-912X
出版年度：2018
卷号：3
期号：4
页码：115-129
DOI：10.1016/j.sesci.2018.06.001
语种：English
出版社：Elsevier
摘要：AbstractThe Triassic alkaline basaltic rocks (TABR) of North Kamarbon are located in Central Alborz, which is regarded as the northern part of the Alpine-Himalayan orogenic belt. Fractional crystallization does not appear as a major process in the genesis of TABR while different degree of partial melting may be regarded as the main process, based on petrography and geochemistry studies. The geochemical characteristics of TABR are in conflict with a substantial involvement of continental crust or crustal contamination. High (La/Yb)Nand (Dy/Yb)Nratios, along with other geochemical features, in the TABR magma, suggest an asthenospheric origin, with low degree of partial melting of a garnet-bearing mantle sources. Enrichment patterns of LILE (Ba, Sr and Th), HFSE (Nb, Ta and Zr) and P, and depletion at HREE (Yb, Lu) are similar to what observed for OIB or intraplate alkaline magmatic rocks. The Sr and Nd isotopic ratios range from 0.70448 to 0.70522 and from 0.51269 to 0.51280, respectively, suggesting time-integrated slightly depleted magma sources. The data indicate that the evolution of TABR could be related to the rifting basin, in Late Triassic, which caused their development by upwelling and decompressional melting of an asthenospheric mantle, without a major involvement of subcontinental lithospheric mantle or crustal contamination.
关键词：KeywordsenMantle sourceRifting basinCentral AlborzIran