摘要
对栗木矿田3个花岗岩体进行了岩石主量元素、微量元素的地球化学研究和分析,岩石化学成分具高铝高硅碱特征,属于高钾钙碱性岩系列;微量元素总量明显偏低,Eu强烈亏损,以富含Li、Rb贫Sr、Ba为特征,花岗岩浆分异度高或岩浆发生过充分的结晶分异作用;推断花岗质岩浆熔出后源区残留相为石榴石+斜长石+钾长石±角闪石±黑云母等组成的麻粒岩相,具深源的特征,在中高—高压条件下部分熔融形成的,同时,受氧逸度(f_(O2))较低、水活度(α_(H2O))较低、水逸度(f_(H2O))较高的制约因素影响。通过对华南地区岩石圈深部动力学背景分析,认为岩石圈减薄合理地解释了本区栗木花岗岩体的形成机制。
This paper conducted geochemical study on the major elements and trace elements of three granite bodies from Limu ore field. The results indicated that the rocks were alkaline rock series with high content of potassium and calcium, and their chemical composition was characterized by high content of aluminum, silicon and alkali. The total content of trace elements was relatively low with intense depletion of Eu, and the rocks were enriched with Li and Rb and were depleted of Sr and Ba. The diversity degree of granitic magma was relatively high or the magma had been suffered from full crystallization differentiation. It is inferred that the residual phase of source area after smelting of granitic magma is granulite facies which consist of garnet ＋ anorthose ＋ potassium feldspar ± hornblende±biotite. The granitic magma has features of anatetic origin, and is formed through partial melting under medium - high to high pressure. Meanwhile, the granitic magma are influenced by restraint factors like low oxygen fugacity （fO2 ）, low water activity （αH2O） and high water fugacity （fH2O）. Based on the analysis on the dynamic background at deep part of lithosphere in South China area, the authors believed that thinning of lithosphere could well explain the formation mechanism of Limu granite bodies in this area.
出处
《矿产与地质》
2016年第6期998-1005,共8页
Mineral Resources and Geology
基金
国土资源部2006年第二批全国危机矿山接替资源勘查项目(编码:200645091)
广西第三批特聘专家"中国有色桂林矿产地质研究院有限公司隐伏矿找矿预测研究"专项资金共同资助
关键词
栗木矿田
源区残留相
制约因素
岩石圈减薄
低速滑脱面
广西
Limu ore field, residual phase of source area, restraint factor, thinning of lithosphere, low-velocity detachment surface, Guangxi
