【摘要】 本文以下扬子区晚石炭世碳酸盐地层内的层状铜、多金属矿床的成矿地质背景、沉积含矿层序内矿石矿物和成矿元素组合、沉积结构构造,成矿温度、同期热液蚀变作用,以及Pb、C、H、O同位素等特征的研究与依据,提出了“沉积-海底喷出沉积成矿模式,即热水溶液在对流循环过程中,从下伏岩石中萃取大量金属,形成含金属热水溶液,再从海底喷出,与海水混合后在适宜的物理化学条件下,金属矿物大量沉淀而形成矿床。更多还原

【Abstract】 The Lower Yangtze area, one of the important metallogenic helts in China, is abundant in iron and base metals (Cu,Pb, Zn) as well as nobel metals (Au, Ag). In recent years, the authors have done much research work on regional geological settings, metallogenie enviroments and meta-llogeny, and suggested that the bedded sulfide deposits in this area are sedimentary-submarine effusive-hydrothermal origin.they are hosted in the strata of carbonate rocks of Middle Carboniferous age. The occurrence of these stratiform Cu deposits exhibits the following feature; 1) they are controlled by several E-W trending fault basins; 2)the orebodies are usually found in bedded form and are deposited and folded synchronously with the hosted rocks;3)frequent occurence of the sedimentary texture and structure of the ore; 4) temperatures of formation within the range of 280-350℃; 5) stable isotopic features are: The isotope of lead in pyrite from bedded ore body bears a character of normal lead of single stage, Its age values are concentrated around 260-340m. y; theδ34S value of sulfide is 4-10‰; the accociated minerals; quartz δ18O=13.4‰ (SMOW),siderite δ18O = 14.25‰. (SMOW) , dolomite in wall rocks δ18O = 17‰.(SMOW) ; quartz δ18OHio=-1.8-5.9‰, mean value = 3.88-4.5‰.δr18OHio of siderite associated with quartz=-0.42-6.67‰, mean value = 3.8-4.8‰; the contemporaneous metamorphic minerals(e. g. serpentine) δDhio=-16 -- 49‰. The above data suggested that the ore forming fluids might be a mixture of brine, meteoric water as well as metamorphic water.During the convection of the fluids they absorbed the metals and finally ascending to the sea floor in the form of metalliferous hydrothermal solution. The effusion and sedimentation of these metal-bearing hydrothermal solution along the fractures or vents would result to the type of ore deposits which bear a character of "sedimentary-submarine effusiue-hydro-thermal origin" .更多还原