摘要
甘肃省金塔县老虎山一带首次发现的华北型富镁埃达克岩,地球化学特征表明具有典型C型埃达克岩特征,表现为高Sr低Y、高钾低钠,富集LREE,亏损HREE,无Eu异常或轻微异常,Mg#值(0.56)等特征显示出具有加厚下地壳部分熔融并和玄武岩浆发生混合作用的产物,暗示志留纪晚期北山古大洋已消亡,明水—公婆泉地体和马鬃山中间地块发生碰撞拼接,为北山构造演化提供了依据。
Northchina-type Mg-rich adakite was first discovered in Laohushan area of Jinta County, Gansu Province. It should be typical C-type adakite due to the geochemical features of high Sr, low Y, high K and Low Na, rich LREE and loss HREE, no or minor Eu anomaly and value of Mg#（0.56）. The authors suggested that the adakite formed from the mixing progress of the melt of thicken crustal basaltic magma, it may support that during Late Silurian Period, Beishan ancient oceans have disappeared, and Mingshui-Gongpoquan terrain collided and collaged with Mazongshan median mass.
出处
《甘肃地质》
2014年第1期28-34,共7页
Gansu Geology
