青海东昆仑五龙沟矿集区深水潭金矿地质地球化学特征及成因研究
发布时间：2018-11-27 20:51
【摘要】：五龙沟矿集区位于青海省都兰县,大地构造位置位于东昆仑造山带中段北缘,区内矿产资源丰富,成矿地质条件优越。五龙沟矿集区主要包括7个金矿区:石灰沟矿区、红旗沟矿区、深水潭矿区、淡水沟矿区、水闸东沟矿区、打柴沟矿区和中支沟矿区。本文以近年取得重大找矿突破的深水潭矿区为主要研究对象,查明其地质地球化学特征及成因。矿区出露地层主要有中元古代长城纪小庙组(Chx)、新元古代青白口纪丘吉东沟组(Qbqj)、早古生代奥陶纪祁曼塔格群变火山岩组(OQb)及第四纪(Q),矿体主要产出于丘吉东沟组和祁曼塔格群变火山岩组与各时期花岗质侵入岩的接触带处。矿区内断裂构造十分发育,一系列NW向断层为主要的控矿和容矿构造。深水潭矿区主要受Ⅺ号断裂带控制,从萤石沟一直延伸至水闸东沟,矿区由3个矿体集中分布区段组成,自东向西分别为:水闸东沟矿段、黄龙沟矿段、黑石沟矿段,共圈定金矿体120条。深水潭金矿热液成矿作用主要可以分为石英硫化物阶段和方解石硫化物阶段,以前者为主。矿石矿物主要为黄铁矿、磁黄铁矿和毒砂,部分矿段可见少量闪锌矿、方铅矿和黄铜矿,脉石矿物主要为石英、长石、角闪石、绢云母、黑云母,部分矿段可见方解石。矿石结构主要为碎裂结构和交代残余结构,矿石构造主要为块状构造、浸染状构造和脉状构造。围岩蚀变类型主要为硅化、绢云母化和少量碳酸盐化等。深水潭矿区样品流体包裹体显微测温结果显示,石英硫化物阶段成矿流体均一温度范围为146.8~393.7℃,峰值区间210~280℃,盐度范围为1.56~13.44 wt%NaCl,峰值区间7~13wt%NaCl,流体密度范围为0.59~0.99g/cm3。激光拉曼光谱成分分析结果显示,流体包裹体中气相除H2O外,也检测到了少量CO2和N2。由此认为成矿流体为一套H2O-NaCl-CO2±N2体系,具有中低温、中低盐度、低密度的特征。H-O同位素测试结果显示,石英硫化物阶段矿化石英脉中石英δ18O值为9.7~15.9‰,估算流体δ18OH2O值为0.3~6.5‰;流体包裹体氢同位素组成范围δD值为-117.3~-87.4‰。分析认为深水潭矿区的成矿流体主要为变质水和大气水的混合,并且随着成矿作用的进行大气降水逐渐占据主导地位。石英硫化物阶段矿石中硫化物硫同位素测试结果显示,其δ34SV-CDT值为0.4‰~8.5‰,平均4.18‰,绝大多数值在3‰到6‰之间,分析表明硫来源不是单纯的岩浆硫来源,推断为成矿热液从围岩中萃取了各类地壳来源硫的混合硫。石英硫化物阶段矿石中硫化物铅同位素测试结果显示,206Pb/204Pb比值为18.1516~18.4985,207Pb/204Pb比值15.4943~15.6320,208Pb/204Pb值为38.3430~39.8076,反映了矿床铅主要来自造山环境中围岩铅。最后,我们认为,深水潭金矿的成矿年代不会早于成矿前闪长玢岩的成岩年龄215Ma,即晚三叠世末期。其成因类型属造山型金矿床。印支晚期的后碰撞造山作用形成了一系列区域性深大断裂和大型剪切带及次级断裂构造,成矿流体可通过这些断裂和剪切带上升并与大气水混合,最终在其内充填交代成矿。
[Abstract]:The five-long-ditch ore-collecting area is located in Duanxian County, Qinghai Province. The geotectonic position is located in the northern margin of the middle section of the East Kunlun orogenic belt. The mineral resources in the region are rich and the ore-forming geological conditions are superior. The five-long ditch mine is mainly composed of seven gold mining areas: the lime-ditch mining area, the red flag-ditch mining area, the deep-water-pool mining area, the fresh-water-ditch mining area, the Donggou mining area of the water gate, the coal-making ditch mining area and the middle-branch ditch mining area. In this paper, the geological and geochemical characteristics and genesis of the deep-water-tan mining area, which has made a major exploration breakthrough in recent years, are studied. In the mining area, there are mainly the Middle Proterozoic, the Great Wall and the small temple group (Chx), the Neoproterozoic Qingbaikou (Qbqj), the early Palaeozoic and the OQb and the Quaternary (Q), The ore body is mainly produced in the contact zone of the volcanic group and the granitoid intrusive rock in the Group of the Donggou Formation of the Chuji and the Zimmerman Group. The fault structure in the mining area is very developed, and a series of NW-trending faults are the main control and ore-bearing structures. The deep-water-pool mining area is mainly controlled by the No. 1 fault zone, and extends from the fluorite ditch to the Donggou of the water gate. The mining area is composed of three concentrated distribution area sections of the ore body. From the east to the west, the Donggou ore section, the Huanglong ditch mine section and the Heishigou Mine section of the water gate are respectively used to delineate the gold orebody 120. The hydrothermal mineralization of the deep-water-tan gold deposit can be divided into the quartz-sulfide phase and the calcite-sulfide stage, and the former is the former. The ore minerals are mainly pyrite, pyrrhotite and arsenopyrite, and a small amount of sphalerite, galena and chalcopyrite are found in some ore sections. The gangue minerals are mainly quartz, feldspar, hornblende, sericite, biotite, and some of the mineral sections can be seen as calcite. The ore structure is mainly of the fracture structure and the metasomatic residual structure, and the ore structure is mainly of massive structure, disseminated structure and vein structure. The type of alteration of surrounding rock is mainly silicon, sericite and a small amount of carbonate. The micro-temperature measurement of the fluid inclusions in the deep water-pool area shows that the temperature range of the ore-forming fluid in the quartz-sulfide stage is 146.8-397.degree. C., the peak interval is 210-280 鈩，
本文编号：2362003
[Abstract]:The five-long-ditch ore-collecting area is located in Duanxian County, Qinghai Province. The geotectonic position is located in the northern margin of the middle section of the East Kunlun orogenic belt. The mineral resources in the region are rich and the ore-forming geological conditions are superior. The five-long ditch mine is mainly composed of seven gold mining areas: the lime-ditch mining area, the red flag-ditch mining area, the deep-water-pool mining area, the fresh-water-ditch mining area, the Donggou mining area of the water gate, the coal-making ditch mining area and the middle-branch ditch mining area. In this paper, the geological and geochemical characteristics and genesis of the deep-water-tan mining area, which has made a major exploration breakthrough in recent years, are studied. In the mining area, there are mainly the Middle Proterozoic, the Great Wall and the small temple group (Chx), the Neoproterozoic Qingbaikou (Qbqj), the early Palaeozoic and the OQb and the Quaternary (Q), The ore body is mainly produced in the contact zone of the volcanic group and the granitoid intrusive rock in the Group of the Donggou Formation of the Chuji and the Zimmerman Group. The fault structure in the mining area is very developed, and a series of NW-trending faults are the main control and ore-bearing structures. The deep-water-pool mining area is mainly controlled by the No. 1 fault zone, and extends from the fluorite ditch to the Donggou of the water gate. The mining area is composed of three concentrated distribution area sections of the ore body. From the east to the west, the Donggou ore section, the Huanglong ditch mine section and the Heishigou Mine section of the water gate are respectively used to delineate the gold orebody 120. The hydrothermal mineralization of the deep-water-tan gold deposit can be divided into the quartz-sulfide phase and the calcite-sulfide stage, and the former is the former. The ore minerals are mainly pyrite, pyrrhotite and arsenopyrite, and a small amount of sphalerite, galena and chalcopyrite are found in some ore sections. The gangue minerals are mainly quartz, feldspar, hornblende, sericite, biotite, and some of the mineral sections can be seen as calcite. The ore structure is mainly of the fracture structure and the metasomatic residual structure, and the ore structure is mainly of massive structure, disseminated structure and vein structure. The type of alteration of surrounding rock is mainly silicon, sericite and a small amount of carbonate. The micro-temperature measurement of the fluid inclusions in the deep water-pool area shows that the temperature range of the ore-forming fluid in the quartz-sulfide stage is 146.8-397.degree. C., the peak interval is 210-280 鈩，
本文编号：2362003
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