【摘要】 腾冲-梁河地区锡矿床是富亲石元素地壳在板块会聚碰撞作用下与再生花岗岩浆活动有关的地球化学旋回中形成的。成矿期前的富集,发生于花岗岩上升侵位、分异演化过程中。由于早期硅酸盐结晶不相容,锡及相关元素逐渐向花岗岩演化序列晚阶段聚集,最终富集于残浆中。残浆在高蒸气压驱动下,向岩基顶部或近侧围岩压力释放带侵位,发生减压沸腾。含矿气-液流体与硅酸盐分离,在非平衡结晶分异条件下,锡及相关元素进入流体相,形成岩浆期后成矿流体。岩浆期后含矿气-液锡的沉淀富集机理决定于成矿流体活动的物理化学场性质。构造封闭岩体内,矿石沉淀富集作用主要由对同源母岩早期晶出的矿物碱交代作用和流体温度压力改变引起的热化学参数变化所形成,产出含锡(钨)-稀有金属变花岗岩型和内云英岩型矿床。构造开放岩体外.成矿流体迁移到长英质围岩断裂-裂隙带中,矿石沉淀富集受减压沸腾和气-液、酸-碱分离作用的制约,并有异源组分加入,产出锡石外云英岩型、富硫化物锡石-石英型矿床。富碳酸盐沉积围岩的物理化学场是以与异源物质交代平衡为主要沉淀富集机理。除接触交代矽卡岩中有部分钙硅酸盐含锡外,随成矿流体与碳酸盐平衡交代进程中流体物理化学条件下的变化,可发生一系列多阶段矿物共生组合,主要有:云英岩化矽卡岩型,含锡硼镁铁矿磁铁矿型,锡石-多金属硫化物型,含锡硫盐-方解石型。在梁河丝光坪尚产出一种以高、低温矿物共生为特点的锡石-木锡石-蛋白石绢英岩型浅成高温热液锡矿床。更多还原

【Abstract】 The tin ore deposits in Tengchong-Lianghe area were formed in the geochemical cycles related to the regenerated granitic magmatism under the convergent and collision process of plates which occurred in the crust with rich lithophile elements contained. The premetallogenic enrichment happened in the course of rise, emplacement and differentiation, evolution of granite. Tin and correiation elements were, toward the late stage of granite evolu-tion series, gradually concentrated and enriched in residual magma finally because of the insoluble property of silicate crystallization in early stage. The residual magma intruded, under the drive of high steam pressure, toward the pressure released belt on the top of bathoiith or nearby country rock and took place tile reduced pressure boiling. Under the conditions of unba-lanced crystalline differentiation and the disconnection of the ore-bearing gas-liquid fluid with silicate, tin and correlation elements entered into the fluid facies and formed the Postmagmatic metallogenic fluid. The deposited and enriched mechanism of the postmagmatic ore-bearing gas-liquid tin was determined by the physical-chemicai field nature for metal-logenic fluid activity. In rock body closed by structures, the ore deposited and enriched process mainly appeared in the alkali-metasomatism of crystal-lized minerals from the parent of the same derivation in early period and the variation of thermal chemical parameter resulted from temperature-pres-sure changes in fluids, thus forming the ore deposits of metagranite and intragreisen types which contained tin, tungsten and rare metal. Out of the structural open rockbody, the metaiiogenic fluid being migrated into the fault-fissure belts of felsic wall rock, the deposit and enrichment of ore were restricted by the reduced pressure boiling and gas-liquid and acid-alkali discon-nection, and joined the different derived component to it, creating the ore deposits of cassiterite extragreisen type and sulfide-rich cassiterite-quartz type. The physical-chemical field of carbonate-rich sedimentary wall rock to-ok the metasomatic balance of heterodefivation matter as the chief deposited and enriched mechanism. In addition to part of calc-silicate in the contact metasomatic skarn having contained tin, paragenetic association of a series of polyphase minerals could occur with the changes of fluid physical-chemical condition in the course of the balance metasomatism between the metalloge-nic fluid and carbonate which largely included the types of greisenization skarn, tin-bearing ludwigite-magnetite, cassiterite-polymetallic sulfide and tin-bearing sulfate-calcite. In Siguangping area of Lianghe county, an xeno-thermal deposit of cassiterite-wood tin-opal-sericite quartz rock type occurred that made a feature of mineral paragenesis of high and low temperature.更多还原