东昆仑夏日哈木铜镍硫化物矿床岩矿石的密度特征与重力勘探问题

The Density Characteristics of Rocks from Xiarihamu Copper Nickel Sulfide Deposit and Problem of Gravity Exploration Deployment in East Kunlun,Qinghai Province

夏日哈木铜镍硫化物矿床是青海省首次发现的岩浆熔离型矿床,属于小岩体成大矿理论实践的又一成果。由于岩体小,物性差异不清楚,在夏日哈木以及外围地区尚未部署重力调查工作。而重力测量是区域上寻找岩体的基本方法之一。如何应用重力测量方法发现更多的小岩体,成为东昆仑地区进一步勘探铜镍硫化物矿床的瓶颈之一。为此,本文利用夏日哈木铜镍硫化物矿区90个钻孔的岩心进行了3694件样品的密度测定。经统计,变质岩、侵入岩、蚀变侵入岩、矿化侵入岩间的密度值具有显著的差异,密度值高异常的空间分布与矿化体空间分布具有对应的关系,本文得出重力测量方法具有分辨侵入岩体与变质岩地层、评价含矿岩体与不含矿岩体的物性基础的结论。但由于岩体、矿体的体积小,且具有一定的埋深,因此建议在东昆仑地区开展以寻找基性-超基性侵入岩体、评价其含矿性为地质任务的重力测量时宜使用大比例尺的工作方法。

Xiarihamu Cu Ni sulfide deposit from magmatic melt is discovered for the first time in Qinghai province, which belongs to the ＂small intrusions forming large deposits＂ geological theory and practice. Because of small rock mass and no clear difference in physical properties, the gravity survey work has not been used to find the rock mass in Xiarihamu area and peripheral region. And the gravity measurement is one of the basic methods to find the rock mass in the region. How to use the method of gravity measurement to find more small rock mass is one of the bottle necks in the further exploration of copper and nickel sulfide deposits in East Kunlun. Therefore, the densities of 3 694 samples were measured by using 90 drill cores in Xiarihamu copper nickel sulfide mining area. And the density characteristics of metamorphic rocks, intrusive rocks, altered intrusive rocks and mineralized intrusive rocks are significantly different, and the relationship between the spatial distribution of the high density anomaly and the spatial distribution of the mineralized body is analyzed. In this paper, the method of gravity measurement has the physical properties of the intrusive rock and metamorphic rocks, and the evaluation of the physical properties of ore bearing rocks and non ore bodies. But due to the small volume of the rock and ore, which has a certain depth, gravity measurement in large scale is suggested in search of mafic ultramafic intrusions and evaluation intrusive rock containing ore in the East Kunlun area.