中国岩浆铜镍硫化物矿床地质特点及其启示

Characteristics and inspirations of the Ni-Cu sulfide deposits in China

我国岩浆硫化物矿床类型比较齐全,产出的构造背景比较复杂,尽管铂族元素矿床比较匮乏,但铜镍矿床资源总量名列世界前茅.不仅在华北克拉通西南缘和峨眉大火成岩省发现了一系列与地幔柱岩浆活动有关的铜镍(铂族元素)矿床,例如金川和杨柳坪超大型铜镍铂族元素矿床;还在中亚造山带南缘境内以及东昆仑造山带发现了一批规模可观的铜镍矿床,甚至超大型矿床,例如夏日哈木超大型镍钴矿床,使得我国产于板块聚合边界铜镍矿床在镍资源总量中所占的比例远高于世界平均值.这种特点一方面取决于我国特殊的地质背景,反映了我国铜镍矿床成因的特点;另一方面也说明我国这类矿床的勘查策略和技术具有优势,我国地质工作者卓有成效的找矿实践极大地丰富了铜镍硫化物矿床的找矿理论,拓展了这类矿床的找矿空间.对华北克拉通、峨眉大火成岩省、中亚造山带南缘及东昆仑造山带已发现矿床的地质特征进行总结,对于未来这些区域找矿潜力的合理评价及预测是非常重要的.

A series of magmatic sulfide deposits, including the giant Jinchuan Ni-Cu-（PGE）deposit in North China Craton and Xiarihamu Ni-Co deposit in central of Tibet Plateau, have been discovered in different tectonic settings in China in past decades. China is one of the countries having largest reserve of Ni metal in the world,and scanty of resource of platinum-group element. The magmatic sulfide deposits in China may be genetically related with the magmatism derived from mantle plumes,such as the Neoproterozoic Jinchuan deposit at the southwestern margin of North China Craton and the Permian deposits in the Emeishan Large Igneous Province,and the magmatism resulted from subduction-collision processes at convergent tectonic settings, such as a series of large Ni-Cu sulfide deposits occur in the southern margins of the Central Asian Orogenic Belt and the East Kunlun Orogenic Belt. Particularly, the proportion of Ni reserve from the deposits in convergent tectonic settings in the total Ni reserve in China is much higher than the average value in the world. This is consistent with geological background of China, in which the Central Asian Orogenic Belt occurs in the northern part and the Tethys Orogenic Belt occurs in the southern part. On the other hand,the discoveries of many Ni-Cu deposits in the orogenic belts reflect that the prospecting strategy and technology on the magmatic sulfide deposit are more advantageous in China than in the other countries. These discoveries are significant for further exploration of Ni-Cu sulfide deposits in the world. Recent studies indicated that the formation of the Huangshan-Jingerquan Ni-Cu deposit zone at the sourtehrn margin of the Central Asian Orogenic Belt is closely related to plate collision coupling with regional shearing. There are still large potential to find new deposits in the regions covered by Quaternary sediments in the Huangshan-Jingerquan zone. New insights by the studies of magma conduit system of the Jinchuan deposit indicated a good prospeeting potential to the depths. Summarizing for the geological characteristics of the Ni-Cu sulfide deposits in North China craton, Emeishan Large Igneous Province,southern margins of Central Asian Orogenic Belt and east Kunlun Orogenic Belt is very important for reasonable evaluation of prospecting potential in these regions.