北山红柳大泉地区侵入岩岩石化学特征及成矿指示意义

北山红柳大泉一带侵入岩广泛分布,但缺乏对年代学研究及其成因和构造背景研究。文章对区内主要岩体进行了同位素年代学和地球化学特征研究,探讨了岩体与区域成矿的关系,岩体侵位时代分别为早志留世和二叠纪花岗闪长岩的锆石U-Pb年龄(440. 2±1. 7) Ma和(434. 1±1. 7) Ma;闪长岩的年龄为(267. 2±3. 7) Ma和(282. 2±3. 7) Ma。本区岩类以二叠纪二长花岗岩和闪长岩类为主;SiO2含量为62. 98%~76. 03%,A/CNK显示样品属于准铝-过铝质岩石,钙碱性-高钾钙碱性系列;稀土元素配分曲线总体呈右倾,轻稀土相对富集,而重稀土相对亏损,个别样品表现出Eu的负异常,均为Ⅰ型花岗岩。早志留世岩体为火山弧花岗岩,与成矿关系不密切;二叠纪花岗岩形成于后碰撞构造环境,二长花岗岩为区内多金属和铀矿形成提供热源和矿源。

Chemical characteristics and metallogenic indications of intrusive rocks in Hongliudaquan area of Beishan

Intrusive rocks are widely distributed in Hongliudaquan area of Beishan, but there is a lack of research on chronology and its genesis and tectonic background. In this paper, isotopic dating and geochemical characteristics of major rock masses in the region are studied, and the relationship between rock masses and regional mineralization is discussed. The time of rock mass invasion was early Silurian and Permian. Zircon U-Pb ages of mononitic granites are (440.2±1.7) Ma and (434.1±1.7) Ma, the ages of diorites are (267.2±3.7) Ma and (282.2±3.7) Ma. The Permian monzonitic granite and diorite are the main types; The content of SiO₂ is within the range of 62.98 to 76.03 %. The A/CNK shows that the sample belongs to quasi-aluminum-superaluminum rock, belongs to the calcium alkaline-high potassium calcium alkaline series, and the rare earth element distribution curve is generally right-leaning, light rare earth. Relatively enriched, The heavy rare earth has a relative loss, and individual samples show negative anomalies of Eu, all of which are type I granite. Early Silurian rock mass is volcanic arc granite, and its relationship with metallogenesis is not close; Permian granites are formed in the post-collision tectonic environment, and the binary granites provide heat sources and mineral sources for the formation of polymetallic and uranium deposits in the region.