综合化探方法在青海夏日哈木超大型铜镍矿床中的找矿应用

夏日哈木矿床是青海省近几年在东昆仑地区发现的首例岩浆熔离型铜镍硫化物矿床,矿床规模达超大型,在其发现及评价过程中,化探综合找矿方法起到了最为主要的作用。在系统评价1∶20万水系沉积物异常→1∶5万水系沉积物地球化学特征→1∶1万土壤异常特征→地质及工程验证的方法组合及应用效果基础上,研究发现:1∶20万水系沉积物测量可大致圈定找矿靶区,但相应地质工作未发现与铜镍矿有关的基性—超基性岩体,引起异常的原因尚不能定性;1∶5万水系沉积物测量进一步分解了1∶20万水系沉积物异常,相应地质工作发现了与铜镍矿有关的基性—超基性岩体,但其含矿性需进一步确认;1∶1万土壤测量进一步缩小了找矿靶区,配套完成的1∶1万地质草测工作,基本查明了引起异常的原因,并详细圈定了含矿基性—超基性杂岩体,为进一步工程验证并发现矿(化)体提供了直接依据。通过研究确认其方法组合是达到最经济成本、最快发现矿体的有效方法组合,可为成矿带相似类型矿床的评价起示范作用。

A study of integrated geochemical exploration method and its application to the Xiarihamu superlarge Cu-Ni deposit,Qinghai Province

The Xiarihamu deposit is the first superlarge magmatic liquation type Cu?Ni sulfide deposit discovered in recent years in East Kunlung area of Qinghai Province. During the process of its discovery and evaluation, the integrated geochemical exploration methods played the most important role. Based on the systematic evaluation of 1 ∶ 200 000 stream sediment anomaly→1 ∶ 50 000 geochemical characteristics of stream sediments→1 ∶ 10 000 composite anomaly→combinational method of geology and engineering verification, the authors found that 1 ∶ 200 000 stream sediment survey could approximately delineate the prospecting target, but the corresponding geo?logical work failed to find the Cu?Ni ore?related basic and ultrabasic rock bodies, and the origin of the anomaly could not be deter?mined. 1 ∶ 50 000 stream sediment survey further decomposed the 1 ∶ 200 000 stream sediment anomaly. The corresponding geological work found some basic?ultrabasic rock bodies related to Cu?Ni ore, but the ore potentiality needs further confirmation. The 1 ∶ 10 000 soil survey further reduced the prospecting target, and supported by the 1 ∶ 10 000 geological sketching, the main causes of anomaly were detected and the ore?bearing basic?ultrabasic rock bodies were delineated in detail. All of these results have provided the direct ba?sis for further engineering verification. It is held that this combinational method is the most economical and fastest way to find the ore?body, and the results obtained by the authors could be regarded as an example to evaluate some deposits similar to the Xiarihamu de?posit in the metallogenic belt.