地学前缘 ›› 2011, Vol. 18 ›› Issue (5): 172-181.

• 论文 • 上一篇    下一篇

新疆西天山大山口金矿地质及成矿流体包裹体地球化学

董新丰, 薛春纪, 石福品   

  1. 1. 地质过程与矿产资源国家重点实验室； 中国地质大学（北京） 地球科学与资源学院， 北京 100083
    2. 新疆维吾尔自治区地质矿产勘查开发局 第三地质大队， 新疆 库尔勒 841000
  • 收稿日期:2011-06-30 修回日期:2011-09-05 出版日期:2011-09-18 发布日期:2011-09-18
  • 作者简介:董新丰（1986—），男，硕士研究生，矿产普查与勘探专业。E-mail:dongxinfeng229@163.com
  • 基金资助:

    国家科技支撑计划项目（2011BAB06B02）；高等学校学科创新引智计划项目（B07011）；长江学者和创新团队发展计划项目（IRT0755）

Geological characteristics and the geochemistry of oreforming fluid inclusions in Dashankou gold deposit, Western Tien Shan, Xinjiang.

  1. 1. State Key Laboratory of Geological Processes and Mineral Resources； School of Earth Sciences and Resources, China University of Geosciences(Beijing), Beijing 100083, China
    2. No3 Geological Party， Xinjiang Uighur Bureau of Geology and Mineral Resources， Kuerle 841000， China  
  • Received:2011-06-30 Revised:2011-09-05 Online:2011-09-18 Published:2011-09-18

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摘要：

新疆和静县大山口金矿位于南天山成矿带东段、哈萨克斯坦—伊犁板块与塔里木板块缝合带附近。矿床处在萨恨托亥—大山口脆韧性剪切带中，矿体以脆韧性变形的上志留—下泥盆统大山口组细碎屑岩、闪长玢岩、英安斑岩为主岩，与围岩的界线模糊。矿体在走向和延深方向上常尖灭再现，局限在脆韧性变形带中，表现为彼此平行的板状、透镜状矿体群或矿带。金矿石类型主要有石英脉型和蚀变岩型，矿石中含少量黄铁矿。对含金脉石英中流体包裹体研究表明，室温下包裹体主要为水溶液包裹体和含CO2包裹体两种类型。流体包裹体气相成分以H2O和CO2为主。流体包裹体均一温度主要集中在260～320 ℃，盐度峰值5.0%～8.5% NaCleq.，流体密度集中变化于0.75～0.95 g/cm3，成矿流体属中温低盐度低密度热液。从流体包裹体估算成矿压力为37.33～109.77 MPa，对应3.73~9.00 km的成矿深度。成矿流体是H2O-NaCl体系并含CO2。大山口金矿床具有造山型金矿的明显特点，找矿潜力大。

关键词: 矿床地质, 流体包裹体, 大山口金矿, 造山型金矿, 新疆西天山

Abstract:

The Dashankou gold deposit in Hejing County, Xinjiang Province is located at the east part of the southern Tien Shan metallogenic belt, and near suture zone between the Tarim and KazakhstanErie Plates. The deposit  occurred in the SahentuohaiDashankou brittleductile shear zones, the gold orebody is hosted in the clastic rocks of the Dashankou Formation and the  Upper Silurianlower Devonian diorite porphyry and dacite porphyry, and the host rocks had undergone the brittleductile deformation. The boundaries between the ore bodies and wall rock are blurred. The ore bodies which are confined to the brittleductile deformation zone obviously show characteristic of thinout reappearing along its strike and tendency, presenting parallel slaty and lenticular ore grops or belts. The natural types of the ore are mainly goldbearing mylonite and quartz veins. The ore contains a small amount of pyrite. The fluid inclusions in the veinquartz of the main mineralization stage were studied. There are two major types of fluid inclusions at room temperature, i.e., the aqueous  and CO2bearing inclusions. The oreforming fluid mainly contains H2O and CO2, and the temperature is between 260320 ℃, the salinity peak is between 500%850% NaCleq., and the density between 075095 g/cm3. The oreforming fluids is mesothermal, low salinity and low density hydrothermal system. The oreforming pressure of 397810977 MPa and corresponding oreforming depths of 499900 km is estimated by the fluid inclusions. The oreforming fluid is a H2ONaCl system bearing CO2. The Dashankou gold deposit shows obviously characteristics of orogenic type of gold deposit with better exploration potentiality.

Key words: ore geolology, fluid inclusions, Dashankou gold deposit, orogenic type of gold deposit, Xinjiang

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