秘鲁胡斯塔铜矿原生晕地球化学特征及找矿效果

LITHOGEOCHEMICAL CHARACTERISTICS OF THE JUSTA COPPER DEPOSIT IN PERU AND THE ORE-PROSPECTING EFFECT

在秘鲁胡斯塔矿区进行1∶2 000地质填图和1∶1万原生晕地球化学测量,把本区划分成东西2个矿化区,8个矿脉带,并圈出26个铜异常。所有已知矿体均有铜异常显示,通过铜异常又新发现了21条铜矿脉。预测由7、8和13号铜异常组成的环状异常下部可能是热液活动或矿化中心,其后的普查勘探证实了这一推断,并发现了一个资源量大于260万t铜金属的大矿床。

1： 2 000 geological map and 1 ： 10 000 lithogeochemical survey covering 2.75 km^2 were completed in Justa area of Peru in 1997. Stratigraphic, structural and magmatic characteristics of this area were studied in detail, two mineralization areas and eight min- eralization vein belts were outlined, in which ninety-six copper orebodies （veins） were delineated. Twenty-six copper anomalies were detected with the anomaly threshold of 800 ppm. Nos. 7, 8 and 13 copper anomalies form a large half egg pattern. Rocks in the mieralization area are rather broken and strongly altered. The half egg shape may represellt the center of hydrothermal activity or mineralization. It was inferred that there might exist a huge primary copper ore body in the depth, and this predication was proved by Chariot Resources Limited which bought the Justa deposit in 2004 and announced that more than 2.6 million tones of copper were found on 28 February, 2006.