【摘要】：扎西康礦床位于北喜馬拉雅金銻成礦帶,關(guān)于其成礦環(huán)境及演化特征尚缺乏系統(tǒng)的研究。而鉛鋅礦床中通過(guò)典型礦物的礦物學(xué)特征的研究對(duì)于指示成礦環(huán)境和成礦過(guò)程具有重要的指示意義。本文在系統(tǒng)劃分扎西康礦床成礦期次(兩期六階段)的基礎(chǔ)上,并分別按照硫化物、硫鹽礦物、含銀礦物等類別對(duì)扎西康礦床開展了礦物學(xué)研究。扎西康礦床閃鋅礦存在三個(gè)世代,第一世代閃鋅礦主要呈他形粒狀產(chǎn)于細(xì)紋層狀錳鐵碳酸鹽;第二世代閃鋅礦主要呈他形粒狀產(chǎn)于團(tuán)塊狀,球狀,環(huán)狀構(gòu)造礦石;第三世代閃鋅礦主要呈角礫狀產(chǎn)于石英脈中。扎西康礦床閃鋅礦形成早期富Fe、Mn,貧Zn;晚期貧Fe、Mn,富Zn。硫銻鉛礦主要以針狀集合體被閃鋅礦包裹,或呈他形粒狀大量充填在石英晶隙中,或呈他形被黃銅礦,錳鐵碳酸鹽等包裹,還有部分以自形針狀生長(zhǎng)在礦物表面;脆硫銻鉛礦呈微細(xì)他形粒狀充填在石英晶隙中,共生礦物是石英、毒砂和黃鐵礦;車輪礦主要呈微細(xì)他形粒狀分布在方鉛礦中或在方鉛礦周邊形成環(huán)邊,共生礦物是方鉛礦、銀黝銅礦和黃銅礦;銀黝銅礦主要呈微細(xì)他形粒狀分布,共生礦物是方鉛礦、車輪礦、硫銻鉛礦。S同位素地質(zhì)溫度計(jì)顯示扎西康第二、三成礦階段溫度分別是242℃~325℃、317℃。閃鋅礦的FeS分子百分含量與硫逸度的關(guān)系,硫鹽礦物組合與溫度和S逸度的關(guān)系顯示,扎西康一至五成礦階段的硫逸度分別為-13.9~-13.2、-14.5~-13.6、-13.3~-9.8、-14.6~-15.6、-16.9~-14.9。表明扎西康礦床成礦早期硫逸度較低,外部流體混合使第三成礦階段硫逸度突然升高并隨著成礦進(jìn)行逐漸降低。錳鐵碳酸鹽中Mn/Fe比值為1.55~0.87,顯示第一成礦期成礦流體處于強(qiáng)還原環(huán)境,并且富含CO2。扎西康礦床第一成礦期成礦流體隨著溫度下降Zn~(2+)、Pb~(2+)大量晶出成礦。第二成礦期成礦流體溫度升高,二世代閃鋅礦和方鉛礦發(fā)生活化、再交代作用。成礦流體混合外部流體使硫逸度上升,大量閃鋅礦和富Ag方鉛礦晶出。進(jìn)入第四成礦階段Pb~(2+)、Sb~(2+)、Ag+、Fe~(2+)、、Zn~(2+)、Cu~(2+)等形成獨(dú)立銀礦物。隨著Ag~+、Zn~(2+)完全消耗,Pb~(2+)和Sb~(2+)主要形成以Pb-Sb硫鹽為主的礦物,Fe~(2+)主要形成黃鐵礦和毒砂,隨著Fe~(2+)、Pb~(2+)消耗完全,成礦流體中Sb~(2+)以輝銻礦的形式沉淀,成礦物質(zhì)消耗完畢,最后以石英±方解石的形式結(jié)束礦化活動(dòng)。
[Abstract]:The Zaxikang deposit is located in the gold and antimony metallogenic belt of the northern Himalayas. There is no systematic study on its metallogenic environment and evolution characteristics. The study of mineralogical characteristics of typical minerals in lead-zinc deposits is of great significance in indicating the metallogenic environment and metallogenic process. On the basis of systematically dividing the metallogenic stages (two phases and six stages) of the Zaxikang deposit, the mineralogical study of the Zaxikang deposit has been carried out according to the types of sulfides, sulphide minerals and silver-bearing minerals. There are three generations of sphalerite in Zaxikang deposit, the first generation of sphalerite mainly occurs in fine lamellar ferromanganese carbonate, the second generation of sphalerite is mainly allograined, spherical and annular structural ore. The third generation sphalerite mainly occurs in quartz vein in the form of breccia. The sphalerite of Zaxikang deposit was rich in Fe ~ (2 +) and Zn in the early stage, and was rich in Fe ~ (2 +) and Zn ~ (2 +) in the late period. Sb-S is mainly encapsulated by sphalerite as acicular aggregates, or filled in quartz intercalations in the form of heteromorphic granulites, or wrapped in chalcopyrite, ferromanganese carbonate, etc., and some of them grow on the surface of minerals in the form of self-shaped needles. The brittle antimony lead ores are filled in quartz crystal interstices in the form of microfine antimony grains, and the symbiotic minerals are quartz, arsenopyrite and pyrite, while the wheel ores are mainly distributed in the galena or form ring edges around the galena, and the symbiotic minerals are galena. Silver tetrahedrite and chalcopyrite, silver tetrahedrite are mainly distributed in the form of microalloid granulites, and the symbiotic minerals are galena, wheel ore, sulphoantimonite. S isotopic geothermometer shows that the temperature of the second and third metallogenic stages of Zaxikang is 242 鈩，

本文編號(hào)：2182666