云南大红山铁铜矿重磁解释

Gravity and magnetic interpretation of Dahongshan iron-copper mine,Yunnan

大红山铁铜矿产于早元古界大红山群红山组、曼岗河组古海相火山岩中。为了详细研究该矿的重磁特征,在矿区布设一条重磁精测剖面,结合物性测试与模型进行重磁正演建模。结果显示:岩矿石磁倾角主要集中在30°附近,与当地的正常倾角吻合,表明基性岩体受后期位移改造不明显;铁矿与红山组表现出高重力高磁异常特征,铜矿与曼岗河组表现出较低的重力与磁异常特征;正演模拟显示铁铜矿应该为重磁同源体,但在地面的响应特征不尽相同。高磁高重的异常响应特征主体应为红山组与其内部的铜铁矿、铁矿,次为曼岗河组与其内部的铜铁矿、铁矿;而铜矿由于埋深较大等原因,重磁响应不明显。

Dahongshan iron-copper mine is produced in ancient marine facies volcanic rocks Early Proterozoic, and also produced in Dahongshan Group’s Honghsan Formation and Manganghe Formation. In order to study the characteristic of gravity and magnetic in detail,a precision profile of gravity and magnetic was laid in the area, and gravity and magnetic forward model created to simulate the characteristic of gravity and magnetic with the physical properties of rocks and ores. The results show that the magnetic dip of rocks and ores is mainly concentrated in the vicinity of 30°, and coincided to the natural magnetic dip of the area. There are no obvious late displacement and reconstruction to the base rock mass. Iron mine and Hongshan Formation show high gravity and magnetic characteristic, while copper mine and Manganghe Formation show lower gravity and magnetic characteristic. Forward modeling of the gravity and magnetic of iron-copper mine should be homologous, but their response character is not necessarily the same on the ground. The main part of gravity and magnetic response characteristic should be the Hongshan Formation and inside copperiron mine and iron mine. The secondary part of gravity and magnetic response characteristic should be the Manganghe Formation and inside copperiron mine and iron mine. And the response characteristic of copper mine is not obvious, maybe deep buried.