地质背景复杂区的找矿技术组合研究——以青海省柳弯区块状硫化物矿床为例

Research on the Combination of Prospecting Techniques in Complicated Geological Background: Taking the Massive Sulfide Deposit in the Liuwanqu Area of Qinghai Province as an Example

青海省柳弯区矿集区内块状硫化物矿床是北祁连地区较为重要的海相火山岩型矿床,矿体赋存于次火山岩中,受后期构造破坏,矿体分布规律难以掌握。自20世纪90年代以来,该区多金属矿找矿利用了地、物、化、遥等多种方法手段,涉及该区及周边各种地质工作较多,但未能系统总结不同方法、不同物化探工作在该区铜多金属矿找矿上的应用效果,因此在找矿方面一直未能取得突破。本次研究从分析多金属矿床覆盖层厚度、矿床和矿体地质特征、不同物化探异常特征入手,总结地质背景下矿化体的物化探特征,进一步缩小找矿靶区,并通过钻探深部验证,在下柳沟、弯阳河、下沟老矿段深部发现隐伏矿体,在老矿段之间的空白区圈定了工业矿体,同时在矿区外围的下沟沟脑-苇夏沟一带发现较好的找矿线索。综合分析认为,本区有效的找矿技术组合为重力+激电+地气+可控源+钻探,可为新一轮找矿突破战略行动中“在哪找、怎么找”提供参考。

The massive sulfide deposits in the Liuwanqu ore concentration area of Qinghai Province are important marine volcanic rock type deposit in North Qilian area.The ore body occurs in subvolcanic rocks,and the distribution of ore bodies is difficult to determine due to late tectonic events.Since the 1990s,the polymetallic ore prospecting in this area has made use of geological,geophysical,geochemical,remote sensing and other methods,involving a variety of geological work in this area and its surrounding areas.However,the application effects of different methods and different geophysical and geochemical exploration in the copper polymetallic ore prospecting in this area have not been systematically summarized,so there has been no breakthrough in the ore prospecting.This work analyzed the thickness of the overburden layer,the geological characteristics of the deposit and ore body,and the characteristics of different geophysical and geochemical exploration anomalies.The characteristics of geophysical and geochemical exploration under the geological background were analyzed to delineated the prospecting target.By deep drilling verification,hidden ore bodies were discovered and industrial ore body was delineated in the unknown area of old oreblock.At the same time,better exploration clues have been proposed in the peripheral area of the mining district,such as Xiaogougounao-Weixiagou.A comprehensive analysis suggests that various geophysical and geochemical exploration methods have shown practical effectiveness in mineral exploration in this area.It is determined that an effective combination of exploration techniques in this area includes gravity surveys,induced polarization,geogas gas surveys,controlled source electromagnetic surveys,and drilling.This can provide valuable reference for"where to explore and how to explore"in the upcoming strategic breakthrough actions in mineral exploration.