摘要
山西吕梁群流纹岩是一个古元古代的弱碱性火山岩。它具有高SiO2、Na2O＋K2O和Zr、Ga等高场强（HFS）元素和高FeO*／MgO、Rb／Sr和Ga／Al比值，以及低CaO、Sr和Eu／Eu*的地球化学特征，相似于A型花岗质岩石。它形成于大陆边缘裂谷环境。化学成分及同位素特征为高εNd（t）值，低（87Sr／86Sr）i值，表明流纹岩的原始岩浆由下地壳晚太古代变质岩受裂谷岩浆和热流作用的影响部分熔融形成，在经以长石为主的结晶分离后最终形成吕梁群A型流纹岩。
The rhyolites in the Upper Luliang Group of Shanxi Province of China are Palaeoproterozoic A-type volcanic rocks. They are characterized by high SiO2, Na2O +K2O, Zr, Nb, Ga, Y and REE contents and large FeO* / MgO, Rb / Sr and Ga / Al ratios, and low CaO, Sr and Eu contents, and formed in the rifting setting of continental margin. Their chemical features and isotopic data (high εNd(t) and low Sr initial ratios) suggest that original granitic magma derived from the partial melting of Late Archean lower crust metamorphic rocks due to the influence of basaltic magma and hot fluid in the rifting. A-type rhyolites formed after the fractional crystallization of the dominant feldspar.
出处
《地球化学》
CAS
CSCD
北大核心
1998年第6期549-558,共10页
Geochimica
基金
国家自然科学基金!49202024
