摘要
凤山铜矿床产于中元古界昆阳群绿汁江组凤山段,其下伏为中元古代晚期的滇中裂陷槽中的狮山铜矿床。凤山铜矿床矿体呈脉状、巢状、囊状,切割围岩,形态产状受断裂构造及狮山段紫色层“刺穿体”的控制,是典型的后生矿床。矿石物质成分(以黄铜矿、斑铜矿为主)、黄铁矿的Co含量(0.6％)及Co/Ni比值(75.71)和硫化物的δ^(34)S值约继承了狮山铜矿床的特点;矿石具碎斑状、角砾状、细脉状和网脉状等后生矿石构造,凤山铜矿床黄铜矿、斑铜矿对各种波长入射光的反射率均高于狮山铜矿床黄铜矿;黄铜矿的Cu、Au、Ag含量高于狮山铜矿的黄铜矿,而S、As、Zn含量低于狮山矿的黄铜矿。基于上述特征,提出了凤山铜矿床的再生成矿模式。凤山铜矿床的成矿物质来自下伏的狮山铜矿床及狮山段紫色层细碧质火山角砾岩,经后期非含矿热液溶解而沿构造上升,而后在覆地层的构造中沉淀、富集而形成再生矿床。
Fengshan Copper deposit is confined to the dolomitite of the Fengshan Member in Luzhijian Formation of Middle Proterozoic Kunyan Group and is associated closely with theunderlying Shishan copper deposit which was formed in Central Yunnan Aulacogen in late Middle Proterozoic Subera. The orebodies occur as vein, nest and chamber cutting the wall rock. Occurrence and shape of the orebodies are controlled by fractures and the diapir in the Violet Horizon of the Shishan Member, being characteristic of typical epigenetic deposit. The ore minerals are predominated by chalcopyrite and bornite. The contents of Co in pyrite are 0. 6% with Co/Ni ratio of 75. 71,the mean S'S values of the sulfides range from +9. 23‰(for chalcopyrite)to +8. 217‰(for pyrite), which might be inherited from Shishan copper deposit. The ores have mortar ,brecciated, veinlet and network structures which are typical of epigenetic ores. Reflectivities of the chalcopyrite and bornite from Fengshan copper deposit are higher than those of chalcopyrite from Shishan copper deposit. The chalcopyrite contains more Cu、Au、Ag、and less S、As、Zn than those from Shishan copper deposit.
On the basis of the above characteristics, a regenerated origin model for Fengshan copper deposit is suggested. The ore material was derived from underlying Shishan copper deposit and spilitic volcanic breccia in the Violet Horizon of the Shishan Member acting as source-beds. The late hyclrothermal fluids abstracted ore material from them, then ,ascended along fractures and fissures in the overlying dolomitite of the Fengshan Member ,discharging and forming regenerated Fengshan copper deposit.
出处
《矿产与地质》
1992年第6期431-439,共9页
Mineral Resources and Geology
关键词
再生成因
成矿模式
铜矿床
Fengshan copper deposit, Regenerated origin. Genetic model of deposit, Yinien copper deposit
