青海肯德可克铁、金多金属矿床地球化学特征及成因

Geochemistry and Genesis of the Kendekeke Iron-gold Polymetallic Deposit in Qinghai Province

青海肯德可克为上世纪60-70年代发现并评价的铁、金多金属矿床,本文对该矿进行较系统的矿床地球化学研究。结果表明,肯德可克矿床赋矿围岩种类多样,化学组成变化很大;其中有一类岩石化学、稀土特征与肯德可克矿区外围-野马泉一带分布的印支-燕山期中酸性岩体相近,表明该矿床的赋存部位为中酸性岩脉的发育地带;铁矿石的稀土元素组成与赋矿围岩既有许多相似之处,也存在一些差异;其硫同位素组成明显有别于我国典型的砂岩型矿床,而与斑岩型和火山岩型相差不大,与矽卡岩型较为一致。因此作者认为肯德可克铁、金多金属矿为热水喷流沉积-岩浆热液叠加的叠生型矿床。

The Kendekeke depsoit is a recently discovered iron-gold polymetatlic deposit in Qinghai province. This paper presents systematic ore deposit geochemical chararcteristics of the deposit. The study indicates that the Kendekeke deposit is hosted in various types of wallrocks, having significantly different chemical compositions. One type of wallrock exhibits similar petrochemical and tara earth element （REE） eharateristies to the Indosinian-Yans- hanian intermediate acidity plutons in the peripheral Yemaquan area, suggesting that the deposit is contained in a region with well-developed intermediate-acidic dykes. The iron ores share similar REE compositions with the orebearing wallrocks, also showing some difference. The sulfur isotopic compositions of the deposit are obviously different from those of the typical sandstone-type depsoit, however, are simlar to those of the porphyry and volcanictypes and consistent with those of the skarn-type. On the basis of the above study, it is suggested that the Kendekeke Fe-Co-Bi-Au polymetallic deposit was formed by exhalative-sedimentation and rebuilding of magmatic hydrothermal fluid.