發(fā)布時間：2018-05-04 06:42

  本文選題：欽杭成礦帶 + 盤龍鉛鋅礦��； 參考：《巖石學報》2017年03期

【摘要】：盤龍鉛鋅礦是近年來在欽杭成礦帶南段新發(fā)現(xiàn)的大型鉛鋅礦床,位于廣西大瑤山西側,屬于桂中坳陷帶與大瑤山隆起的結合部位。它的容礦圍巖為泥盆紀上倫組白云巖。成礦過程可分為三個成礦期:1)原生沉積期,以星散狀構造、似層狀-條帶狀構造、浸染狀構造、膠狀-變膠狀構造、草莓狀構造、揉皺構造等礦石組構特征為代表;2)活化改造期,成礦元素重新活化富集形成網脈狀構造、假角礫狀構造、環(huán)帶構造、晶洞構造、小球狀構造、交代結構、壓力結構等;3)地表氧化期,原生的硫化物在地表被氧化。本研究系統(tǒng)分析了原生沉積期和活化改造期重晶石內的流體包裹體特征。包裹體巖相學分析顯示,兩個期次的流體包裹體類型均比較簡單,主要為富液相的氣液兩相包裹體。顯微測溫結果顯示,原生沉積期均一溫度范圍110.0~234.3℃(平均值為147℃),鹽度介于0.33%~15.57%NaCleqv之間(均值為7.09%Nacleqv)。活化改造期均一溫度稍低于原生沉積期,但鹽度卻明顯高于前者,均一溫度范圍107.9~179.5℃(平均值為139℃),鹽度范圍1.81%~21.24%NaCleqv(均值為10.90%Nacleqv)。拉曼分析測試顯示,兩個成礦期次流體包裹體氣相組分主要為H_2O。原生沉積期和活化改造期成礦流體均具有中低溫、低鹽度和貧CO_2的特征。結合重晶石礦物的產出狀態(tài),原生沉積期流體特征與SEDEX型礦床流體特征相吻合,而對其改造的后期流體與淺成低溫熱液礦床或者SEDEX型礦床流體特征相符。聯(lián)系到區(qū)域演化歷史及海底熱水的幕式噴發(fā)特征,本研究認為,盤龍鉛鋅礦是典型的古生代熱水噴流沉積疊加后期改造成礦的復合"二階段成礦作用"的結果,對古生代地層中SEDEX型礦床的改造動力來源于后期淺成低溫熱液活動,也可能是晚期的又一次熱水噴流活動。
[Abstract]:Panlong Pb-Zn deposit is a large Pb-Zn deposit newly discovered in the southern section of Qinghang metallogenic belt in recent years. It is located on the west side of Dayaoshan in Guangxi and belongs to the combination of Guizhong depression and Dayaoshan uplift. Its ore-bearing surrounding rock is dolomite of Devonian Shanglun formation. The metallogenic process can be divided into three metallogenic stages: 1) primary depositional stage, with scattered structure, lamina-banded structure, disseminated structure, glue-metamorphic structure, strawberry structure, and so on. The ore-fabric characteristics such as crinkle structure and so on are characterized by the activation and transformation of ore-forming elements, the reactivation and enrichment of ore-forming elements into net-vein structure, pseudo-breccia structure, annular structure, crystal cavity structure, small globular structure, metasomatic structure, etc. Pressure structure et al. (3) during the surface oxidation period, primary sulphides are oxidized on the surface. The characteristics of fluid inclusions in barite during primary deposition and activation transformation are systematically analyzed in this study. The petrographic analysis of inclusions shows that the types of fluid inclusions in the two stages are relatively simple, mainly gas-liquid two-phase inclusions rich in liquid phase. The results of microthermometry show that the homogenization temperature range of primary deposition period is 110.0 ~ 234.3 鈩，

本文編號：1842004