李康宁,金鼎国,蔡龙,逯文辉,马原,吕菊蕊.早子沟金矿黄铁矿标型特征及其地质意义[J].甘肃地质,2014,23(2):33-40
早子沟金矿黄铁矿标型特征及其地质意义
Typomorphism and Its Geological Significance of Pyrite in Zaozigou Gold Deposit
  
DOI:
中文关键词:  早子沟  金矿  黄铁矿  成分标型  硫同位素
英文关键词:Zaozigou gold deposit  pyrite  typomorphism  sulfur isotope
基金项目:本文由甘肃省科技计划资助,项目编号1306FGA011
作者单位
李康宁 甘肃省地矿局第三地勘院甘肃 兰州 730050 
金鼎国 甘肃省地矿局第三地勘院甘肃 兰州 730050 
蔡龙 甘肃省地矿局第三地勘院甘肃 兰州 730050 
逯文辉 甘肃省地矿局第三地勘院甘肃 兰州 730050 
马原 甘肃省地矿局第三地勘院甘肃 兰州 730050 
吕菊蕊 甘肃省地矿局第三地勘院甘肃 兰州 730050 
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中文摘要:
      早子沟金矿位于西秦岭同仁—夏河—岷县金成矿带, 矿区赋矿地层为三叠纪中统古浪堤组一段细碎屑岩, 中性岩脉大量发育。矿体产于地层、脉岩及其接触带中, 严格受断裂构造控制。 本文通过对不同期次、 不同矿石类型的黄铁矿进行分布、形态、矿物组合、元素组成以及硫同位素的研究,发现不同矿石类型的黄铁矿形成于不同的深度和地质环境; 主成矿期黄铁矿以五角十二面体为主, 常具碎裂结构; 严重亏铁亏硫, ω(Au)/ω(Ag)=5.54,ω(Co)/ω(Ni)=4.2,类似于卡林型金矿特征,又兼有岩浆型矿床的特征;矿体中黄铁矿硫同位素δ34S‰变化范围-7.43‰~-8.62‰,与围岩黄铁矿硫同位素组成接近,说明硫主要来源于沉积地层,同时由于构造活动和岩浆侵入作用对硫同位素分馏产生了一定影响,使重硫有所富集。
英文摘要:
      Zaozigou gold deposit is located in the Tongren-Xiahe-Minxian gold metallogneic belt of west Qinling orogenic zone. It is hosted in the fine-grained clastic rocks in lower segment of Middle-Triassic Gulangdi Formation. Intermediate rocks are well developed in the ore district. Ore bodies occur in the strata as well as in the dikes and contact zones. Ore bodies are strictly controlled by fractures and faults. Through the study of distribution, shape, mineral association, elemental composition and sulfur isotopes of pyrites, we found that the pyrite from different ore types and different stages should be formed in the various depth and geologic environment. Main-stage pyrites are mainly pentagonal dodecahedron with cataclastic texture, Fe-poor and S-poor. Ratios of ωAu/ωAg(5.54) and ωCo/ωNi(4.2) are similar to carlin-type deposits, but also similar to characteristics of magmatic deposits. The δ34S‰ values of pyrites range from -8.62‰ to -7.43‰ which are similar with sulfur isotopic composition of diagenetic pyrites, indicating that sulfur is mainly from sedimentary strata. Heavy sulfur is slightly enriched because of tectonic activity and magma intrusion.
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