中国含硫化铜镍矿床的超基性岩成因

通过对我国含镍超基性岩矿物学、岩石学、常量元素、稀土元素、锶同位素、硫同位素等几方面成因证据的初步讨论,发现其成矿物质来源于地幔,含矿岩浆是上地幔局部熔融直接产生的,并且是地幔熔融程度较低的结果,其相对富集了钛、铝、钙、钠、钾、稀土、锶及成矿元素等元素。这种含矿岩浆或含镍建造与底辟过程及洋壳无关,而主要分布在稳定大陆地块活动边缘,极少数情况下沿深大断裂侵入到地块内部。硫化铜镍工业富集需要相对稳定的构造环境,构造长期活动,使得含矿岩浆能够上侵到地壳浅部并发生良好的结晶——重力分异作用和硫化物——硅酸盐熔离作用,并进而富集成矿。

GENESIS OF THE ULTRABASIC ROCKS BEARING THE Cu-Ni SULFIDE DEPOSITS IN CHINA

In this paper,after an initial discussion of the genesis evidences of minerlogy, petroloty, main elements, REE, Sr isotopes and S isotopes etc. concerned with the Ni - bearing ultrabasic rocks in China, authors find the forming materials come from the mantle and the ore magma can be produced by the melting part of upper mantle where the degree of melting in the upper mantle is lower. The ore magma are relatively rich in Ti,Ca,Al,Na,K,REE,Sr and ore-forming elements. This ore- bearing magma is independent of the diapire process or ocean crust. It is largely distributed in the mobile margins of stable continental blocks and in few cases it can invade into the interior of the blocks along large and deep rifts. The industrial enrichment of Cu-Ni sulfide needs a relatively stable structure environment, and the long - time movement of structures makes ore magma invade into the shallow crust, gives rise to better crystallization, gravity differentiation and liquation of sulfides and silicates, and further forms ores.