粤北始兴地区水系沉积物测量地球化学特征及找矿预测

Geochemical Characteristics of Stream Sediment Survey and Prospecting Prediction of Shixing Area,Northern Guangdong

始兴地区位于湘赣粤三省交界处,南岭成矿带的东段。区内成矿地质条件优越,钨锡、稀有及稀土金属矿产均较为丰富,其中钨和锡都是我国的优势矿产资源,其矿床尤其引人注目。本文在1∶5万水系沉积物测量成果资料的基础上,对粤北始兴地区的W、Sn、Mo等14种元素地球化学特征进行了初步总结,发现该区与钨有关的成矿伴生元素丰度均远大于区域元素丰度,其中W平均值为37×10^(-6),峰值为2980×10^(-6),Sn平均值为21×10^(-6),峰值为787×10^(-6);元素分布特征显示中下泥盆统是区内W、Mo、Bi等元素的主要富集层位,燕山期侵入岩中Sn、Bi、Wo、W、Zn等元素富集程度也较高;数理统计显示区内W、Sn、Mo、Bi、Pb、Ag等元素之间相关性较强;R型聚类分析显示区内元素组合主要有W-Mo和Pb-Zn-Ag等;因子分析显示区内的主要成矿组合为W-Sn-Mo-Bi-CuPb-Zn-Ag。本次工作共计圈定了21个以W-Sn为主的组合异常,并在空间上形成北北东向和近东西走向的两个综合异常带,结合区内成矿地质条件和异常检查工作,优选了南山坑和良源综合异常区为区内成矿远景最好的靶区。本文以南山坑综合异常区为例,指出该区良好的钨锡多金属矿找矿前景,同时该区的找矿方向可从传统的石英脉型黑钨矿向矽卡岩型钨锡矿和岩体型钨钼多金属矿转变,进而在该区实现找矿突破。

Shixing area is situated on the east of the Nanling multi-metallic mineralized belt,which is located at the junction of Hunan,Jiangxi and Guangdong provinces.It has superior ore-forming geological condition,abundant mineral resource,such as tungsten,tin,rare and RE mineral resources,both tungsten and tin among them are the predominant mineral resource in China,deposits of them are especially remarkable in this area.Based on the 1∶50,000 scale of stream sediment survey results of Shixing area in Northern Guangdong,this paper preliminarily summarized the geochemical characteristics of 14 elements such as W,Sn,Mo.The results indicate that the abundance of metallogenic associated elements related to tungsten are highly greater than the abundance in region,the W abundance value on average is 37×10^（-6） with the peak in 2980×10^（-6）,while the average value of Sn is 21×10^（-6） with peak value is 787×10^（-6）;it also shows that the main rich metallogenic elements such as W,Mo,Bi belong to the Middle-Lower Devonian strata from distribution characteristics of elements,and high abundance of elements such as Sn,Bi,Mo,W,Zn is also observed in Yanshanian intrusive rocks.The mathematical statistics shows close correlation between elements such as W,Sn,Mo,Bi,Pb and Ag,while the results of R-cluster analysis indicate WMo and Pb-Zn-Ag as major element associations in the area.Factor analysis demonstrates that W-Sn-MoBi-Cu-Pb-Zn-Ag are the major metallogenic assemblage in the region.The study has defined 21 composite anomalies focusing on W-Sn,and delineated two integrated anomaly belts in NNE and EW directions respectively,in combination with the metallogenic geological conditions and anomaly inspection results,finally selected the two premium composite anomalies located in Nanshankeng and Liangyuan as the favorable ore-prospects in the survey area.In this paper,we focus on anomalies of Nanshankeng,and point out the good prospects for finding tungsten-tin polymetallic ore.In addition,we suggest that the oreprospecting directions changes from the quartz vine-type tungsten deposit traditionally to skarn-type tungsten-tin deposit and granite-type tungsten-molybdenum polymetallic deposit,in that case it may become a prospecting breakthrough in this area.