胶东不同类型金矿氧同位素地球化学成矿特征及产状模式  

OXYGEN ISOTOPIC GEOCHEMISTRY CHARACTERISTICSAND THE OCCURRENCE MODEL FOR DIFFERENT STYLEGOLD DEPOSITS IN EASTERN SHANDONG AREA

作　　者：陈振胜[1] 张理刚[1] 刘敬秀[1] 王炳成 徐金方 郑文深 

机构地区：[1]宜昌地质矿产研究所 [2]山东省地质科学研究所

出　　处：《华南地质与矿产》1996年第4期44-51,共8页Geology and Mineral Resources of South China

摘　　要：通过对胶东区域招莱、栖霞和牟乳三个主要金矿成矿带中典型矿床蚀变体系岩石氧同位素组成三维变化规律的研究,总结出焦家式破碎蚀变岩型金矿、金青顶式单脉型金矿、玲珑式脉状金矿和马家窑式脉状金矿蚀变体系氧同位素组成变化规律、成因属性及其与金成矿的关系.焦家式金矿则属大气降水热液成因,其氧同位素空间变化规律明显,地表高而深部低;金青顶式金矿尽管产状与焦家式不同,但成因属性及蚀变体系与焦家式极相似;玲珑式和马家窑式金矿则同属岩浆热液水成因,并具相似的蚀变岩石氧同位素组成特征,但玲珑式金矿产于花岗岩中,而马家窑式金矿赋存于胶东群变质岩中.文中提出胶东区域不同类型金矿产状模式.Stable isotope geochemistry studies made on a variety of gold deposits and prospects in eastern Shandong have come to conclusions that there are 4 main styles of gold mineralization, i.e., (1) the Jiaojia style fractured shatter-altered rock type meteoric water genesis hydrothermal Au deposit; (2)the Jinqingding style vein-type meteoric water genesis hydrothermal Au deposit; (3) the Linglong style vein-type magmatic water genesis hydrothermal Au deposit; and (4)the Maji-ayao style vein-type magmatic water genesis hydrothermal Au deposit. Systematic oxygen isotope studies on altered rock system are carried out in some typical Au deposits in this district. Vertical variation characteristics in oxygen isotopic compositions are discussed.The Jiaojia style gold deposit involves an evolutional trend of upward increase in δ18O values of the mineralized altered rock. δ18O values are lower in the deep but higher in subsurface than that of protolith. The systematic decrease of δ18O values of the deeper rocks owe to the effect of meteoric water interacting with wall rocks, which causes <518O values of fluid to 'drift' greatly(especially when water to rock ratio is low). When 16O content in hydrothermal fluid become less as it ascends continuously and as the temperature lowers, δ18O values of altered rocks decrease less with the increasing height. Finally, at a point, the inversed evolutional 18O-higher altered rocks occur at the upper level. In some cases, δ18O values of surface or subsurface altered rocks are somewhat smaller than those underlied (but still greater than that of protolith). The reason for this probably is that when 18O-higher altered rocks occur, 16O content in the fluid increases again. Additional meteoric water into the subsurface open system is also an alternative.The Jinqingding style gold deposit, which is also meteoric water genesis, shares almost the same δ18O evolution trend as that of the Jiaojia style, although the Jinqingding ore deposits occur as auriferous quartz vein plus pyritization ph

关 键 词：氧同位素 地球化学 产状模式 金矿床 成矿特征 

分 类 号：P618.510.4[天文地球—矿床学] P618.510.5[天文地球—地质学]