赛什塘矿区侵入岩的地球化学特征及构造环境分析

青海赛什塘地区岩体分布普遍,是多期次侵入的结果。岩体主要以高钾、过铝质、同属钙碱性系列为特征,具有较低含量的稀土元素丰度值,轻稀土富集,重稀土亏损,铕异常不明显,属I型花岗岩。岩体有Y/Tb值高低不同的两个源区,一是由柴达木地块东南缘岩石圈地幔构成的地幔楔形体,另一个是受其它物源污染的岩浆,是岛弧形成过程中不同阶段的产物。矿区内发现埃达克岩,岩体富含成矿元素,为成矿提供了物质条件。

Geochemical characteristics and tectonic environment analysis of the intrusive rocks in Saishitang ore field

Magmatic bodies widely occur in Saishitang area of Qinghai province as a result of intrusion through several periods.They are characterized by high Potassium and extra Aluminum and all belonging to Calcium-alkali series.The magmatic bodies can be classified as I pattern granite with lower REE abundance,accumulation of light REE and loss of Heavy REE and weak Europium anomaly.There are two different source areas with higher or lower value Y/Tb ratio in the magmatic bodies,one being a mantle wedge composed of lithosphere mantle at the southeastern margin of Qiadam massif,while the other being a magmatic body contaminated by the matter from other source as a result of different phases of island arc formation process.Adakite rock which is rich in ore forming elements was found in the ore field,providing matter condition for mineralization.