摘要
辽宁红透山太古宙块状硫化物型铜锌矿床成矿后的变质作用达到高角闪岩相 ,并经历了 3个阶段的变形。矿床的主要矿石矿物为黄铁矿、磁黄铁矿、黄铜矿和闪锌矿。主矿体内分布有 30多条矿石糜棱岩带 ,它们大多数平行或近于平行块状硫化物矿层 ,少数产在矿体附近围岩中。带中的各种硫化物矿物均遭受了强烈的剪切变形 ,其中黄铁矿以碎裂为主 ,而磁黄铁矿、黄铜矿和闪锌矿显示强烈的塑性。矿石糜棱岩比块状硫化物矿石明显富集铜、金、银等元素 ,其铜、金和银平均含量分别达1 1 .0 0 % ,1 .74g/t和 2 35g/t,相对于块状矿石的富集系数分别为 5 .3、5 .0和 4 .6。这些金属的高度富集主要是因为矿石糜棱岩受到了后期流体的叠加。铅同位素组成表明矿石糜棱岩中的金属一部分来自块状矿石 ,另一部分来自块状硫化物矿体之外。
The post metallogenic metamorphism of Hongtoushan Archean Cu-Zn massive sulphide deposit, Liaoning Province of NE China, belongs to upper amphibolite facies with three phases of deformations. Ore minerals in the deposit are dominated by pyrite, pyrrhotite, chalcopyrite and sphalerite. There are more than 30 mylonite-type oreshoots found inside the main massive sulphide orebodies. Most of them run parallel or sub-parallel to the strike of the massive sulphide ore layers with only a few being developed in metamorphic rocks in the immediate vicinity of the sulphide orebodies. Almost all the sulphide minerals in the oreshoots have been affected by intense ductile shearing. Pyrite is characterized by cataclastic flow, while pyrrhotite, chalcopyrite and sphalerite exhibit strong plasticity. Cu, Au and Ag in ore mylonite are averaged in 11.00 wt%, 1.74 g/t and 235.2 g/t respectively. Compared to the massive sulphide ores, ore mylonites show remarkable enrichment of these elements with enrichment coefficients of 5.3, 5.0 and 4.6 respectively. The high enrichment of these ore-forming metals is basically due to the overprinting of late-stage fluids on ore mylonites. The composition of lead isotopes suggests that the metals in the ore mylonites were derived partly from the original massive ores, and partly from outside the massive ores. Both ductile shearing and fluid overprinting took place during retrograde metamorphism.
出处
《地学前缘》
EI
CAS
CSCD
2004年第2期339-351,共13页
Earth Science Frontiers
基金
国家自然科学基金资助项目 ( 4 0 172 0 3 4)
关键词
块状硫化物矿床
矿石糜棱岩
韧性剪切带
再活化
铅同位素
红透山
辽宁
massive sulphide deposit
ore mylonite
ductile shear zone
remobilization
lead isotopes
Hongtoushan
Liaoning Province
