摘要
斯弄多铅锌矿床位于西藏日喀则南木林盆地,形成于印度-欧亚大陆碰撞背景下。该时期目前已发现如斯弄多、纳如松多、査孜、轧轧龙等大量铅锌矿床,这些矿床具有相似的赋矿围岩和矿石类型,但均存在地球物理研究工作开展极少,围岩和矿石物性不明等问题。为了查明这些矿床的地球物理特征及地球物理找矿方法的适用性,本文以斯弄多铅锌矿床为例,采用激电中梯测量、激电测深和音频大地电磁测深,结合地质资料综合分析,以2.5%为矿区视极化率异常下限,并以此为依据在矿区圈定出主矿体北部受后期断层破坏后的位置,异常强度高,极大可能为矿体引起,并通过实施验证钻孔发现了矿体。由于矿石和赋矿围岩物性差异较大,电法在产于林子宗群火山岩中的脉型、隐爆角砾岩型铅锌矿找矿工作中适用性强,可推广至整个冈底斯林子宗群火山岩带中应用。
Located in the Nanmulin Basin of Xigaze,Tibet,the Sinongduo lead-zinc deposit was formed in the background of the India-Eurasia continental collision,where a large number of lead-zinc deposits such as Sinongduo,Narusongduo,Chazi and Zhazhalong have been discovered.These deposits have the similar host rocks and ore types,but the physical properties of the rocks and ores remain unclear because of the lack of physical work.In order to find out the geophysical characteristics of these deposits and the applicability of geophysical methods,the authors took the Sinongduo lead-zinc deposit as a study case to apply geophysical methods such as induced polarization intermediate gradient,induced polarization sounding and audio magnetotelluric sounding in exploration.Based on the comprehensive analysis of geological and geophysical data,the authors hold that the apparent chargeability of 2.5%should be the boundary between the ore and the host rocks.The location of the northern part of the main orebody destroyed by later fault was inferred in the survey area where the anomalies are strong and have high probability caused by orebody,and this conclusion was proved to be reliable according to the mineralized drill holes.In general,electrical methods exhibit high applicability in exploring the vein type and cryptoexplosive type lead-zinc deposits formed in the Linzizong volcanic rocks due to the difference in physical properties between the ore and the host rocks and can be recommended to the whole Gangdise Linzizong Group volcanic rock belt in prospecting.
作者
杨宗耀
张崇海
张乐骏
郎兴海
赵晓彦
严成明
YANG Zong-yao;ZHANG Chong-hai;ZHANG Le-jun;LANG Xing-hai;ZHAO Xiao-yan;YAN Cheng-ming(Faculty of Geosciences and Environmental Engineering,Southwest Jiaotong University,Chengdu,Sichuan 611756;College of Earth Sciences,Chengdu University of Technology,Chengdu,Sichuan 610059;Centre of Excellence in Ore Deposit(CODES),University of Tasmania,Hobart,Australia 7001;No.605 Geological Party of Geological Exploration and Resources Development,Meishan,Sichuan 620860)
出处
《地球学报》
EI
CAS
CSCD
北大核心
2020年第1期107-116,共10页
Acta Geoscientica Sinica
基金
国家重点研发计划-深地专项(编号:2018YFC0604105)
国家自然科学基金项目(编号:41772075)联合资助~~
关键词
音频大地电磁测深
激电中梯
激电测深
斯弄多
林子宗群
冈底斯
audio magnetotelluric sounding
IP intermediate gradient
IP sounding
Sinongduo
Linzizong Group
Gangdise
