The Hongshan porphyry-cryptoexplosive breccia type copper deposit occurs in a metamorphic rock series of the Mesoproterozoic Zhongcun Group. Orebodies are distributed inside and outside porphyry-cryptoexplosive brecci...The Hongshan porphyry-cryptoexplosive breccia type copper deposit occurs in a metamorphic rock series of the Mesoproterozoic Zhongcun Group. Orebodies are distributed inside and outside porphyry-cryptoexplosive breccia pipes. The deposit involves five ore-forming types, i.e the porphyry type, cryptoexplosive breccia type, contact-zone veinlet-disseminated type, in-pipe fracture-zone filling-replacement type and out-of-pipe fracture-zone filling-replacement type, forming an ore-forming system of “five ore-forming types within a single rock body”. Fluid inclusion and isotope geochemical studies indicate the following: S, Pb, O and Sr were derived from the lower crust, Nd was derived from the continental crust or depleted mantle and rare earth elements (REE) and trace elements have the crustal source characters; fluids consist dominantly of formation water, metamorphic water and ***meteoric water with a part of magmatic mater, heat came from porphyry while the latter originated from partial melting caused by shear heating in the lower crust and upper mantle. According to its origin the deposit is classified as the hypabyssal and near-surface, meso- and hypothermal copper deposit associated with the late Yanshanian porphyry-cryptoexplosive breccia.展开更多
The Hongshan copper deposit is a typical cryptoexplosive breccia-type deposit, which occurs in a metamorphic rock series of the Mesoproterozoic Taoxiyuan Formation. Orebodies are distributed inside and outside porphyr...The Hongshan copper deposit is a typical cryptoexplosive breccia-type deposit, which occurs in a metamorphic rock series of the Mesoproterozoic Taoxiyuan Formation. Orebodies are distributed inside and outside porphyry-cryptoexplosive breccia pipes. The isotope geochemistry of the deposit is consistent with the origin of porphyry breccia: the δ18OH2O values ranging from 1.2‰ to 6.1‰ and the δ34S values varying from 0 to 2.5‰. 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb ratios of pyrite, which coexists with ore minerals, indicate it was derived from the orogenic belt. Thermodynamic analysis indicates that the main metals were deposited largely as a result of the decreasing of proton concentrations associated with H2S and CO2 exsolution during explosion and temperature dropping. Based on K-Ar dating of quartz coexisting with ore minerals, the age of mineralization was estimated to be 97.1–98.8 Ma, which suggests that mineralization occurred between the Early and Late Cretaceous. According to the relevant information obtained, a diagenetic and metallogenic pattern in the area has been presented in this paper.展开更多
红山铜矿床位于三江地区义敦岛弧南端的中甸弧,是在晚三叠世甘孜-理塘洋盆向西俯冲过程中形成的一个中型规模的矽卡岩矿床。通常,矽卡岩体就是铜矿体或铜矿化体,主要呈似层状、层状、脉状及透镜体状产于大理岩与角岩接触带或局部在角岩...红山铜矿床位于三江地区义敦岛弧南端的中甸弧,是在晚三叠世甘孜-理塘洋盆向西俯冲过程中形成的一个中型规模的矽卡岩矿床。通常,矽卡岩体就是铜矿体或铜矿化体,主要呈似层状、层状、脉状及透镜体状产于大理岩与角岩接触带或局部在角岩中,未见其与侵入岩直接接触。通过对不同成矿阶段所形成的石榴石、磁铁矿、磁黄铁矿、黄铁矿、黄铜矿、方解石等典型矿物以及大理岩的稳定同位素特征研究,发现矽卡岩的最主要组成矿物石榴石的δ^(18)O_(SMOW)范围为6.2～8.3‰,反映了矽卡岩可能直接继承隐伏斑岩体的氧同位素组成。根据磁铁矿的氧同位素组成(5.5～7.1‰)所计算的磁铁矿化阶段成矿流体的δ^(18)O_(SMOW)为13.1～14.7‰(400℃)或12.5～14.1‰(500℃),暗示有富集δ^(18)的 CO_2溶入到成矿流体中。硫化物的δ^(34)S_(CDT)范围4.45～6.20‰,说明矿床具有高度均一的硫源,并且在硫化物的结晶沉淀过程中,流体中硫同位素分馏很弱。由此推测主成矿期成矿流体的δ^(34)S_(ΣS)为5.6±0.6‰。矿床中的大理岩的δ^(13)C_(PDB)为2.0～2.2‰,δ^(18)O_(SMOW)为24.0～24.8‰,说明大理岩是由海相碳酸盐岩经重结晶作用而成。成矿晚期阶段形成的方解石脉的δ^(13)C_(PDB)范围是-2.4～1.7‰,δ^(18)O_(SMOW)范围是16.3～22.4‰,表明其 C 和 O 主要来源于大理岩。总之,我们推测红山矽卡岩很可能主要是由中酸性岩浆浅成侵位时局部同化碳酸盐围岩所形成的一种富含钙质成分的次生岩浆就位于碎屑岩与碳酸盐岩之间的构造薄弱带冷凝固结而成,矽卡岩型矿化与深部斑岩型矿化具有共同的成矿物质和成矿流体来源。展开更多
文摘The Hongshan porphyry-cryptoexplosive breccia type copper deposit occurs in a metamorphic rock series of the Mesoproterozoic Zhongcun Group. Orebodies are distributed inside and outside porphyry-cryptoexplosive breccia pipes. The deposit involves five ore-forming types, i.e the porphyry type, cryptoexplosive breccia type, contact-zone veinlet-disseminated type, in-pipe fracture-zone filling-replacement type and out-of-pipe fracture-zone filling-replacement type, forming an ore-forming system of “five ore-forming types within a single rock body”. Fluid inclusion and isotope geochemical studies indicate the following: S, Pb, O and Sr were derived from the lower crust, Nd was derived from the continental crust or depleted mantle and rare earth elements (REE) and trace elements have the crustal source characters; fluids consist dominantly of formation water, metamorphic water and ***meteoric water with a part of magmatic mater, heat came from porphyry while the latter originated from partial melting caused by shear heating in the lower crust and upper mantle. According to its origin the deposit is classified as the hypabyssal and near-surface, meso- and hypothermal copper deposit associated with the late Yanshanian porphyry-cryptoexplosive breccia.
文摘The Hongshan copper deposit is a typical cryptoexplosive breccia-type deposit, which occurs in a metamorphic rock series of the Mesoproterozoic Taoxiyuan Formation. Orebodies are distributed inside and outside porphyry-cryptoexplosive breccia pipes. The isotope geochemistry of the deposit is consistent with the origin of porphyry breccia: the δ18OH2O values ranging from 1.2‰ to 6.1‰ and the δ34S values varying from 0 to 2.5‰. 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb ratios of pyrite, which coexists with ore minerals, indicate it was derived from the orogenic belt. Thermodynamic analysis indicates that the main metals were deposited largely as a result of the decreasing of proton concentrations associated with H2S and CO2 exsolution during explosion and temperature dropping. Based on K-Ar dating of quartz coexisting with ore minerals, the age of mineralization was estimated to be 97.1–98.8 Ma, which suggests that mineralization occurred between the Early and Late Cretaceous. According to the relevant information obtained, a diagenetic and metallogenic pattern in the area has been presented in this paper.
文摘红山铜矿床位于三江地区义敦岛弧南端的中甸弧,是在晚三叠世甘孜-理塘洋盆向西俯冲过程中形成的一个中型规模的矽卡岩矿床。通常,矽卡岩体就是铜矿体或铜矿化体,主要呈似层状、层状、脉状及透镜体状产于大理岩与角岩接触带或局部在角岩中,未见其与侵入岩直接接触。通过对不同成矿阶段所形成的石榴石、磁铁矿、磁黄铁矿、黄铁矿、黄铜矿、方解石等典型矿物以及大理岩的稳定同位素特征研究,发现矽卡岩的最主要组成矿物石榴石的δ^(18)O_(SMOW)范围为6.2～8.3‰,反映了矽卡岩可能直接继承隐伏斑岩体的氧同位素组成。根据磁铁矿的氧同位素组成(5.5～7.1‰)所计算的磁铁矿化阶段成矿流体的δ^(18)O_(SMOW)为13.1～14.7‰(400℃)或12.5～14.1‰(500℃),暗示有富集δ^(18)的 CO_2溶入到成矿流体中。硫化物的δ^(34)S_(CDT)范围4.45～6.20‰,说明矿床具有高度均一的硫源,并且在硫化物的结晶沉淀过程中,流体中硫同位素分馏很弱。由此推测主成矿期成矿流体的δ^(34)S_(ΣS)为5.6±0.6‰。矿床中的大理岩的δ^(13)C_(PDB)为2.0～2.2‰,δ^(18)O_(SMOW)为24.0～24.8‰,说明大理岩是由海相碳酸盐岩经重结晶作用而成。成矿晚期阶段形成的方解石脉的δ^(13)C_(PDB)范围是-2.4～1.7‰,δ^(18)O_(SMOW)范围是16.3～22.4‰,表明其 C 和 O 主要来源于大理岩。总之,我们推测红山矽卡岩很可能主要是由中酸性岩浆浅成侵位时局部同化碳酸盐围岩所形成的一种富含钙质成分的次生岩浆就位于碎屑岩与碳酸盐岩之间的构造薄弱带冷凝固结而成,矽卡岩型矿化与深部斑岩型矿化具有共同的成矿物质和成矿流体来源。
