海水交代过程中细碧角斑岩的矿物组合和矿物成分的变化规律——以陕西略阳细碧角斑岩为例

Mineral Assemblage and Compositional Evolution of Spilitic Keratophyre during the Interaction between Basaltic Andesite and Seawater: Spilitic Keratophyre Located in Lueyang, Shaanxi

对陕西略阳细碧角斑岩的矿物学、岩石学、岩石地球化学、以及全岩O同位素的研究 ,认为细碧角斑岩是海水与玄武安山岩的交代产物 ;交代作用初期岩石中的Na2 O含量升高 ,而MgO、CaO降低 ;交代作用后期岩石中的MgO升高而Na2 O含量降低 ,即在整个过程中岩石的Na2 O含量有一个最大值 ,而MgO有一个最小值。矿物组合由钠长石、绿帘石、少量绿泥石组成 ,最终产物为绿泥石和石英。

Mineralogical, petrology geochemical and whole rock oxygen isotopic studies of spilitic keratophyres located in Lueyang, Shaanxi Province show that the rocks were formed by the interaction between basaltic andesite and seawater. During the hydrothermal metamorphism, there existed two stages characterized by the variations of MgO and Na 2O. During the late stage, the mineral assemblage changed from albite + epidote + actinolite to albite + chlorite + quartz, and finally to chlorite + quartz, which seems to be a stable assemblage.