湘南绿紫坳锡多金属矿床硅钙面控矿作用及其找矿意义

Ore-controlling Effect and Prospecting Significance of Silica-calcium Plane of Luziao Tin Polymetallic Deposit in Southern Hunan Province

湘南地区是南岭地区重要的锡多金属矿勘查区,勘查区的控矿规律研究是实现找矿突破的关键环节。以大义山矿田绿紫坳锡多金属矿床为例,通过野外地质调查和室内综合研究,总结了锡多金属成矿规律,认为锡多金属矿体主要受3类硅钙面控制:Ⅰ类为花岗岩体与碳酸盐岩的“硅钙面”接触界面,形成了Ⅰ号矿带的矽卡岩型铜锡矿体;Ⅱ类为泥盆系上统锡矿山组下段灰岩与上段碎屑岩界面,形成了Ⅱ~Ⅴ号矿带的锡铅锌矿体;Ⅲ类为泥盆系中统跳马涧组砂岩与棋梓桥组灰岩的硅钙界面,形成了Ⅵ和Ⅶ号矿带的锡铅锌多金属矿体。结合成矿地质条件和控矿规律,构建了锡多金属构造控矿模式。综合分析了区内控矿要素特征,认为白水源地段为有利找矿靶区。通过勘查发现了7条锡铅锌多金属矿体,产于第Ⅰ类硅钙面中铜锡矿体1条、第Ⅱ类硅钙面中锡铅锌矿体1条、第Ⅲ类硅钙面中锡铅锌矿体1条,断裂带中矿体4条,获得锡铅锌资源量约1.5万t,取得了矿床南部锡多金属矿的找矿进展。通过对比分析湘南地区香花岭矿田和荷花坪矿田等重要锡多金属矿床,认为硅钙面控矿对湘南地区锡多金属矿具有普遍意义,加强硅钙面的控矿规律研究对于指导湘南地区锡多金属找矿突破具有重要意义。

The Southern Hunan Region is an important tin polymetallic ore exploration area in Nanling area,and the study of ore-control regularity in the exploration area is the key link to achieve prospecting breakthrough. Taking Luziao Tin Polymetallic Deposit in Dayishan Orefield as an example,the metallogenic regularity of tin polymetallic deposit was summarized through field geological survey and indoor comprehensive study. It is considered that the tin polymetallic orebody is mainly controlled by three types of silica-calcium plane:Type Ⅰ is the contact interface of the " silica-calcium plane" between granites and carbonate rocks,forming skarn type Cu-Sn orebody in No. Ⅰ ore zone;The second type is the interface between the lower limestone and the upper clastic rock of the upper Devonian Xikuang Formation,forming the Sn-Pb-Zn orebody in the Ⅱ-Ⅴ ore belt;Class Ⅲ is the silicon-calcium interface between the middle Devonian Jigmajian Formation sandstone and Qiziqiao Formation limestone,forming Sn-Pb-Zn polymetallic orebodies in No. Ⅵ and No. Ⅶ ore belts. Combining with metallogenic geological conditions and ore-controlling regularities,a tin polymetallic structure ore-controlling model was established. Based on the comprehensive analysis of the features of ore-controlling elements in the area,the Baishuihuan Section is considered to be a favorable prospecting target area. Seven Sn-Pb-Zn polymetallic orebodies were discovered through exploration,including one Cu-Sn orebody in Class Ⅰ silica-calcium plane,one Sn-Pb-Zn orebody in class Ⅱ silica-calcium plane,one Sn-Pb-Zn orebody in class Ⅲ silica-calcium plane,and four orebodies in fault zone. The resource amount of Sn-Pb-Zn is about 15 000 t,and the prospecting progress of tin polymetallic deposit in the southern part of the deposit has been made. Through the comparative analysis of important tin polymetallic deposits such as Xianghualing Orefield and Hehuaping Orefield in Southern Hunan Province,it is concluded that the silica-calcium plane ore control is of universal significance to tin polymetallic deposits in Southern Hunan Province,and strengthening the study of silica-calcium plane ore control rules is of great significance to guide the breakthrough of tin polymetallic ore prospecting in Southern Hunan Province.