Sr-Nd-Pb isotopes of the Early Paleozoic mafic-ultramafic dykes and basalts from South Qinling belt and their implications for mantle composition

被引：0
作者：
ChengLi Zhang
Shan Gao
HongLin Yuan
GuoWei Zhang
YunXiang Yan
JingLan Luo
JinHai Luo
机构：
[1] Northwest University,State Key Laboratory of Continental Dynamics, Department of Geology
[2] China University of Geosciences,State Key Laboratory of Geological Progresses and Mineral Resources
来源：
Science in China Series D: Earth Sciences | 2007年 / 50卷
关键词：
mafic dykes; Sr-Nd-Pb isotope; mantle source; South Qinling belt;
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学科分类号：
摘要：
Late Early Paleozoic mafic-ultramafic dykes and volcanic rocks from the South Qinling belt are characterized by ɛNd(t) = +3.28 − +5.02, (87Sr/86Sr)i = 0.70341 − 0.70555, (206Pb/204Pb)i = 17.256 − 18.993, (207Pb/204Pb)i = 15.505 − 15.642, (208Pb/204Pb)i = 37.125 − 38.968, Δ8/4=21.18 − 774.43, Δ7/4 = 8.11 − 18.82. These charac-teristics suggest that they derived from a Middle Neoproterozoic mantle with isotopic compositions of mixed HIMU, EMII and minor EMI components. We interpret that these rocks were melting products of depleted mantle modified by subducted ancient oceanic crust and continental margin sediments along the northern margin of Yangtze block during Early Neoproterozoic.
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页码：1293 / 1301
页数：8
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