Nd, Sr and O Isotopic Study on Spilite-Keratophyre in Xiqiu,,Zhejiang Province, China

查看全文 作　　者：Shen Weizhou;Zhang Bangtong;Ling Hongfei;Lai Mingyian;Yang Jiedong;Tao Xiancong Department of Earth Sciences, Nanjing University, Nanjing, Jiangsu Modern Analysis Centre, Nanjing University, Nanjing, Jiangsu 出　　处：《Acta Geologica Sinica(English Edition)》索引1992年第66卷第2期,共12页 摘　　要：Nd, Sr and O isotopic study on the spilite-keratophyre sequence in Xiqiu shows that its ∈_Nd values are inthe range of 4.02-5.26, and its ∈_Sr values, +1.4-2.6. According to the points of these data in the ∈_Nd-T,∈_Sr-T and ∈_Nd-∈_Sr diagrams, the spilite-keratophyre is interpreted as being slightly contaminated by crustalmaterials. Its δ¹⁸O values are 3.9-5.0‰. The depletion of ¹⁸O in the rocks resulted from the influence ofseawater hydrothermal alteration during or soon after the rock formation. Based on the isotopic characteristicsand available geochemical data, it is believed that the spilite-keratophyre was formed in the well-developedisland-arc environment during the Late Proterozoic subduction of the palaeo-Pacific plate beneath thesoutheastern margin of the Yangtze massif. 关 键 词：ISOTOPIC SUBDUCTION Yangtze geochemical depletion mantle China ND margin MAGMA