盛源盆地及邻区橄榄玄粗岩系列火山岩的矿物学证据及成因探讨

Mineralogy evidence of shoshonite rock series from Shengyuan basin and it's adjacent area

笔者采用电子探针技术对赣中盛源盆地及邻区的中(基)性熔岩进行研究,首次发现岩石基质中的斜长石微晶具有钾长石环边的矿物学特点,这是橄榄玄粗岩系列火山岩最重要的矿物学证据;通过对黑云母化学成分的研究,发现研究区黑云母为镁质黑云母,属于幔源深成岩浆系列,形成于高碱度环境,与钙碱性系列岩石中的黑云母形成环境不同,从矿物学角度说明其寄主岩石具有橄榄玄粗岩的特征。这对探讨该地区橄榄玄粗岩系列火山岩的成因具有一定的意义。

This paper presents a systematic study of the mineralogy, petrology of volcanic rocks in Shengyuan basin and it＇s adjacent area of middle Jiangxi. By studing it＇s groundmass using electron microprobe, we have found the mineralogical features such as orthoclase rims around the plagioclase for the first time, which is identified to be the evidence for shoshonite rock series. By studing the chemical composition of biotite, it is suggested that the biotites are phlogopites-Mg-rich biotites, belong to the magmas origined in deep mantal and formed in high alkaline environment which differ from cals-alkaline rocks and are identified minerallogically to be rocks of shoshonite series too. Studies on the shoshonite series in Shengyuan basin and it＇s adiacent area are quite significant to the discussion on magmas genesis and condition.