摘要
闽东西朝钼矿成矿岩体具高SiO_(2)、富Al_(2)O_(3)、高Sr,低Y、Yb、MgO,高Sr/Y比值和(La/Yb)_(N)比值的地球化学特征,为典型的埃达克质岩的特征。该岩体具有较低的Ni、Cr和V含量,稀土元素配分为典型的轻重稀土强烈分馏右陡倾,微量元素蛛网图上表现出Rb、Ba、Th、U等LILE富集,P、Ti等HFSE强烈亏损、Sr富集,(^(87)Sr/^(86)Sr)_(i)比值为0.709778~0.710097,εNd(t)值为-7.09~-5.77,这些特征均与华夏地块早白垩世加厚下地壳部分熔融成因的埃达克质岩特征相近。西朝钼矿的成岩成矿是早白垩世挤压向伸展拉张构造环境转换的背景下,在地幔物质上涌加热作用下,加厚的下地壳发生部分熔融且有幔源物质加入形成的。
Xichao molybdenum mineral mass in Eastern Fujian have eochemical behavior of high SiO_(2),rich Al_(2)O_(3),high Sr,,low Y,Yb,MgO,high Sr/Y ratio and(La/Yb)N ratio,which are feature of typical adakitic rock.The rock body has lower content of Ni,Cr and V.Rare earth distribution is divided into the typical weight of the rare earth strong fractionation of the right steep dip.The web map of trace element shows LILE enrichment of Rb,Ba,Th,U,HFSE loss of P,Ti,and Sr enrichment.(^(87)Sr/^(86)Sr)_(i)ratio is 0.709778~0.710097 and Nd(t)value is-7.09~-5.77.These features are similar to the Edac rock characteristics of the Early Cretaceous thickened crust.The diagenesis and mineralization of Xichao molybdenum deposit was formed by partial melting of the thickened lower crust and the addition of mantle-derived materials under the upwaging and heating of mantle material under the background of the transformation from compression to extensional environment in the Early Cretaceous.
作者
周小栋
Zhou Xiaodong(Fujian Institute of Geological Survey,Fuzhou,350013)
出处
《福建地质》
2021年第2期85-97,共13页
Geology of Fujian
基金
中国地质调查局基础地质调查项目“福建1∶5万建瓯市、南雅、玉山、西溪幅区域地质矿产调查”
