赣南晚侏罗世橄榄玄粗岩系列的发现

对赣南三百山盆地晚侏罗世武夷群火山岩的岩石地球化学特征进行了系统研究。根据岩石Na2O K2O含量9.84%～10.74%,K2O/Na2O值1.99～2.52,高铝(ω(Al2O3)>15%)、低钛(ω(TiO2)<0.50%)、贫铁(TFeO=3.15%～3.50%),确定三百山盆地火山岩属长英质橄榄玄粗岩系列。同时根据岩石富集大离子亲石元素、铕正异常等稀土元素、微量元素特征,认为三百山盆地火山岩是挤压构造环境下,深部地幔含石榴石斜长角闪岩部分熔融的产物。

The Discovery of Late Jurassic Shoshonitic Rocks in South Jiangxi

A systematic study of the petrology and geochemistry of volcanic rock located in Sanbaishan basin of South Jiangxi are gived.The volcanic rock is characterized by:Na2O K2O content 9.84%~10.74%,K2O/Na2O ratio 1.99~2.52,high Al content(w(Al2O3)>15%),low Ti content(w(TiO2)<0.5%),low Fe content(Total Fe content 3.15%~3.50%).It is identified to be felsic shoshonitic rocks.According to the characters of rare earth element(REE) and trace element,such as LILE-rich and positive Eu anomaly,it is supposed that Sanbaishan volcanic rock is the production of partial melting of garnet-plagioclase-bearing amphibolite in the deep mantle under compressed tectonic setting.