北羌塘新生代火山岩长石矿物激光探针原位测试及其微量元素特征初探

THE IN SITU LA-ICP-MS ANALYSIS AND TRACE ELEMENT FEATURES FOR THE FELDSPARS FROM CENOZOIC TRACHYANDESITE IN NORTH QIANGTANG, TIBETAN PLATEAU

利用电子探针和激光探针剥蚀系统 (LA ICP MS) ,对北羌塘半岛湖新第三纪粗面安山岩中的碱性长石和斜长石进行了系统分析 ,讨论了激光探针原位 (insitu)测试方法的有关细节及其对暗色矿物和浅色矿物的耦合性。在此基础上分析归纳了本区长石矿物中痕量元素及稀土元素地球化学性状。结果表明 ,长石中强烈地富集了Rb、Sr、Ba和Eu ,在两类长石中 ,无论是大离子亲石元素还是稀土元素 ,均未显示明显的选择性富集规律。

Based on the electron microprobe (EMP) and laser ablation inductively coupled plasma mass spectrometer (LA ICP MS) analyses, the major and trace element features of the feldspars from the Cenozoic trachyandesite of north Qiangtang were discussed in this paper. The results indicated that all of the feldspars exhibited Rb, Sr, Ba and Eu enrichment. Especially, the REE distribution patterns of the potassium feldspar and the plagioclase were much similar each other.