摘要
大坪金矿床是三江(金沙江、澜沧江、怒江)金矿带的主要矿床之一。矿体产在哀牢山变质带南西侧的闪长岩体中,岩体出露面积约100平方公里,呈北西—南东长条状分布,北西端倾伏于哀牢山变质带中,北东和南西两侧分别与泥盆纪和奥陶纪地层呈断层接触。大坪金矿床属金-硫化物-石英脉型多金属矿床,矿脉产出严格受构造的控制,多充填在北西向的容矿断裂中。矿脉一般长几十至几百米,最长达2000米左右;厚O.2—1.5米,局部达2米左右。矿石的主要矿物共生组合为石英-黄铁矿-方铅矿-黄铜矿-自然金(含量依次递减),并有少量闪锌矿、锡石、磁铁矿、黝铜矿、毒砂、脆硫锑铅矿、重晶石、方解石及白云石等。矿石的主要工业元素为Au、Pb,综合利用组分有Ag、Cu等。自然金以粒度0.07—
The Daping gold deposit belongs to a polymetallic deposit of gold-sulfidequartz vein type of which the pyrites are of the highest contents in metal minerals and most important loading gold and typomorphic minerals. Obvious typomorphic characteristics of pyrites in ore deposit are as follows: (1) The pyrites are divisible into four created stages among them the second stage was the main formation period for pyrites and the pyrites formed in the second and third stages show the best auriferous properties; (2) The best auriferous properties are found in pyrites when the elements of As, Sb, Bi, Cu, Pb and Zn, etc. are higher in them and Cu>Pb>Zn in contents; (3) Most thermoelectric coefficients in pyrite are positive, belonging to the hole conductance type (type Pelectric conductivity), it means that the explroatory depths only reach the upper part of the ore deposit at present, still with a better prospect in existence downwards; (4) A distinct infrared absorbed peak of 1050—1100 cm^(-1) in Au-rich pyrites and frequent undulation of infrared spectral curves are observed; (5) There is a positive correlation between the auriferous properties and edge line length of pyrite unit cell and the best mineralizations occur in the pyrites, middle part of the ore bodies, with the biggest unit cell parameter; (6) The sulfur isotopic composition in pyrites indicates that whose oreforming materials originated from magmatic hydrothermal solution and the decrepitation temperature of pyrites shows that the metallization took place under a moderate temperature category.
出处
《云南地质》
1989年第3期249-255,共7页
Yunnan Geology
