摘要
根据岩石成分与磁性,已将个旧花岗岩杂岩体划分为高磁性与低磁性两大系列:第一组高磁性相,很可能属于特殊的Ⅰ型花岗岩,并与氧化型夕卡岩锡矿的形成有关;第二组低磁性相,属于 S 型花岗岩,与还原型锡石硫化物夕卡岩锡矿的形成有关。在矿物共生组合分析、相平衡、相图研究的基础上,系统地测定了个旧主要工业类型锡矿床(还原型锡石硫化物夕卡岩锡矿)形成的热力学参数,阐明其成因机理,还原夕卡岩主要造岩硅酸盐矿物钙铁辉石,通过反应(3)进行硫化反应,形成大量的磁黄铁矿。这是一条硫的缓冲平衡反应曲线,因此,所有热力学参数,如温度、硫逸度、氧逸度等均在比较严格和狭窄的范围内变化。通过自然界反应的产物证实了 Gamble 相图的应用范围。
Based on their compositions and magnetic properties,the granite complexes in Gejiu aredivided into two broad categories:highly magnetic and low magnetic series.The former maybe designated to type-Ⅰgranites which seem to be associated with oxidization-type skarn tindeposits while the latter belongs to type-S granites which are associated wi(?)h reduction-typecassiteritesulfide skarn tin deposits.On the basis of mineral association,phase equilibrium andp(?)ase diagram systematic determinations have been carried out of the thermodynamic parametersfor the major tin deposits of commercial importance in Gejiu(the reduction-type cassiterite-sulfide skarn tin deposits).In addition the mechanism of their formation has also beenelaborated,i.e.,reaction(3)of hedenbergite—a major skarn rock-forming silicate mineral pro-duced a large amount of pyrrhotite.Since such a reac(?)ion is presented by a buffer equilibriumreaction curve for sulfide,all the thermodynamic parameters such as temperature,sulfur fugacityand oxygen fugacity are variable within a restricted and narrow range.The products producedfrom natural reaction provide evidence for the application of Gamble phase diagrams.
出处
《地球化学》
CAS
CSCD
北大核心
1993年第2期146-154,共9页
Geochimica
