安徽黄梅尖地区地面伽玛能谱钾差量异常特征及与铀成矿关系分析研究

Potassium dispersion anomalies characteristics from ground gamma-ray spectrometric survey in the Huangmeijian area Anhui province and its relationship with uranium mineralization

铀成矿信息提取和识别是当前铀矿地质找矿工作的研究热点之一.本文利用地面伽玛能谱钾测量数据,采用差量法对铀成矿信息进行提取,结果显示,黄梅尖地区钾差量正值域与负值域呈不均匀面状展布,且具有跨越不同侵入期次岩石单元现象,钾差量亏损场与铀矿床(点)的空间位置显示较好的对应关系,反映了铀成矿作用与钾差量亏损场具有成因联系.结合野外地质调查、显微岩石学和元素地球化学对比研究表明,钾差量亏损场的形成是成矿流体与围岩作用导致水云母、钠长石、绿泥石交代钾长石的结果,是一个铀元素富集、钾质含量流失的过程;依据钾差量亏损场可大致圈定与铀成矿密切相关的"褪色"蚀变作用的空间分布范围,进一步突显了岩体内带铀矿找矿的有利信息,缩小了找矿靶区;初步划分白虎山地段和黄龙桥-4340矿点一带两处铀成矿有利地段,对下一步岩体内带铀矿找矿工作具有重要的指示作用.

The extraction and identification of uranium metallogenic information is one of the hot spots in the current uranium geological prospecting work.In this paper,the differential method is used to extract uranium metallogenic information from ground gamma-ray spectroscopy potassium measurement data,the results show that the positive and negative potassium difference domains in Huangmeijian area are unevenly distributed in a plane,it also has the phenomenon of rock units spanning different intrusive stages,The spatial position of the potassium difference depletion field and the uranium deposit(point)shows a good correspondence,reflecting the genetic relationship between uranium mineralization and the potassium difference depletion field.Combining field geological survey,microlithology and element geochemistry,it is shown that the formation of potassium deficit field is the result of metasomatism of potassium feldspar by hydromica,albite and chlorite caused by the interaction between ore-forming fluid and surrounding rock,it is also a process of enrichment of uranium and loss of potassium content.Based on the potassium deficit field,the spatial distribution range of“fading”alteration closely related to uranium mineralization is been roughly delineated,which further highlighted the favorable information for prospecting uranium deposits in the intrusive zone of the rock mass,it also narrows the prospecting target area.Two favorable uranium mineralization sites are preliminarily divided into Baihushan site and Huanglongqiao-4340 ore spot,it is of great significance to the next stage of uranium prospecting in the intrinsic zone of rock mass.