蚌埠—五河地区绿岩带金矿地质特征及控矿因素  

GEOLOGICAL CHARACTERISTICS AND ORE-CONTROL FACTORS OF GOLD DEPOSITS IN THE GREENSTONE BELT OF BENGBU-WUHE AREA

作　　者：涂荫玖 陈成涛 

机构地区：[1]安徽地矿局312地质队

出　　处：《矿床地质》1993年第1期38-47,共10页Mineral Deposits

摘　　要：通过铅、硫、氢、氧同位素以及不同层位、岩石金丰度的大量统计,成矿与构造、岩浆岩关系研究,表明金的成矿作用具有多来源、多成因、多阶段的特点,金矿有明显的层控性,晚太古代西堌堆组绿岩是金的矿源层。区域东西向复式背斜和南北向韧性剪切带分别控制了成矿区和矿田、矿床、矿体的分布。金矿主要形成在燕山期中温、中深成条件下的脆一韧性变形环境。Large quantities of analyses and statistics of gold abundance in different strata and locks combined with lead isotope data suggest that greenstone of Late Archean Xigudui Formation is the source bed of gold deposits. The regional EW-trending anticlinorium and the SN-trending ductile shear zones control the distribution of metallogenic provinces and that of ore fields, ore deposits and orebodies respectively. 47% of known gold deposits and ore (mineralization)spots are distributed within or near Tancheng-Lujiang faulted zone, and auriferous quartz veins with economic significance all occur in subsidiary SN-trending ductile shear zones, 1～2 km from the major fault. From Tancheng-Lujiang faulted zone outwards, in conformity with the falling ore-forming temperature and pressure, grain sizes of native gold become smaller, fineness, δ^(34)S values and Co/Ni as well as Se/Te ratios of pyrite decrease, and Au/Ag ratio tends to increase. Strain analysis shows that gold deposits and spots are mostly located in areas where (?)_s=0.6～0.9, while mineralization is rather weak in areas with (?)_s larger than 1 or smaller than 0.5. This coincides with the conclusion drawn from the research that gold of wall rocks within the ductile shear zone is most abundant in the moderate shear strain (γ)area, suggesting the mobilization and migration of gold in the strong deformarion part and precipitation and enrichment of gold in the moderate strain part. Gold metallization shows polystage, polysource and polygenetic characteristics; nevertheless, the major ore-forming process took place in Yanshanian period in a brittle-ductile detormation environment of intermediate structural layer, with ore-forming temperature 438～132℃, pressure 5.45×10~7～6.53×10~7 Pa and depth 1.98～2.37 km.

关 键 词：金矿床 地质特征 控矿因素 绿岩带 

分 类 号：P618.510.2[天文地球—矿床学]