The Hujiayu Cu deposit,representative of the ＂HuBi-type＂ Cu deposits in the Zhongtiao Mountains district in the southern edge of the North China Craton,is primarily hosted in graphitebearing schists and carbonate ro...The Hujiayu Cu deposit,representative of the ＂HuBi-type＂ Cu deposits in the Zhongtiao Mountains district in the southern edge of the North China Craton,is primarily hosted in graphitebearing schists and carbonate rocks.The ore minerals comprise mainly chalcopyrite,with minor sphalerite,siegenite[（Co,Ni）_3S_4],and clausthalite[Pb（S,Se）].The gangue minerals are mainly quartz and dolomite,with minor albite.Four fluid inclusion types were recognized in the chalcopyrite-pyrite-dolomite-quartz veins,including CO_2-rich inclusions（type Ⅰ）,low-salinity,liquid-dominated,biphase aqueous inclusions（type Ⅱ）,solid-bearing aqueous inclusions（type Ⅲ）,and solid-bearing aqueous-carbonic inclusions（type Ⅳ）.Type I inclusion can be further divided into two sub-types,i.e.,monophase CO_2 inclusions（type Ⅰa） and biphase CO_2-rich inclusions（with a visible aqueous phase）,and type Ⅲ inclusion is divided into a subtype with a halite daughter mineral（type Ⅲa） and a subtype with multiple solids（type Ⅲb）.Various fluid inclusion assemblages（FIAs） were identified through petrographic observations,and were classified into four groups.The group-1 FIA,consisting of monophase CO_2 inclusions（type Ⅰa）,homogenized into the liquid phase in a large range of temperatures from-1 to 28℃,suggesting post-entrapment modification.The group-2 FIA consists of type Ⅰb,Ⅲb and Ⅳ inclusions,and is interpreted to reflect fluid immiscibility.The group-3 FIA comprises type Ⅱ and Ⅲa inclusions,and the group-4FIA consists of type Ⅱ inclusions with consistent phase ratios.The group-1 and group-2 FIAs are interpreted to be entrapped during mineralization,whereas group-3 and group-4 FIAs probably represent the post-mineralization fluids.The solid CO_2 melting temperatures range from-60.6 to56.6℃ and from-66.0 to-63.4℃ for type Ⅰa and type Ⅳ inclusions,respectively.The homogenization temperatures for type Ⅱ inclusions range from 132 to 170℃ for group-3 FIAs and115 to 219℃ for group-4 FIAs.The halite melting temperatures range from 530 to 562℃ for typeⅢ b and Ⅳ inclusions,whereas those for type Ⅲa inclusions range from 198 to 398℃.Laser Raman and SEM-EDS results show that the gas species in fluid inclusions are mainly CO_2 with minor CH_4,and the solids are dominated by calcite and halite.The calcite in the hosting marble and dolomite in the hydrothermal veins have δ^（13）C_（V-pdb） values of-0.2 to 1.2‰ and-1.2 to-6.3‰,and δ^（18）O_（v-smow） values of 14.0 to 20.8 ‰ and 13.2 to 14.3‰,respectively.The fluid inclusion and carbon-oxygen isotope data suggest that the ore-forming fluids were probably derived from metamorphic fluids,which had reacted with organic matter in sedimentary rocks or graphite and undergone phase separation at 1.4-1.8 kbar and 230-240℃,after peak metamorphism.It is proposed that the Hujiayu Cu deposit consists of two mineralization stages.The early stage mineralization,characterized by disseminated and veinlet copper sulfides,probably took place in an environment similar to sediment-hosted stratiform copper mineralization.Ore minerals formed in this precursor mineralization stage were remobilized and enriched in the late metamorphic hydrothermal stage,leading to the formation of thick quartz-dolomite-sulfides veins.展开更多
The new type of copper deposits concerned with in this paper are vein copperdeposits found in the Lanping-Simao Rift Basin, Yunnan, China. As is indicated by H,O, C, S, Pb and Sr isotopes, water and mineralisers in th...The new type of copper deposits concerned with in this paper are vein copperdeposits found in the Lanping-Simao Rift Basin, Yunnan, China. As is indicated by H,O, C, S, Pb and Sr isotopes, water and mineralisers in the ore-forming fluids were derivedfrom heated meteoric waer and mantle, respectively. The metallic elements (Cu, Ag, Pb,Zn, As, Sb, Fe, REE, etc.) are characterised by a mised source from the crust and themantle.展开更多
Shizishan ore-field is a nonferrous and noble metal ore-field which is most rich in copper and gold.There are many types of fluid inclusions in minerals of the deposits.The homogeneous temperatures and the salinities ...Shizishan ore-field is a nonferrous and noble metal ore-field which is most rich in copper and gold.There are many types of fluid inclusions in minerals of the deposits.The homogeneous temperatures and the salinities of the fluid inclusions in main mineralization stages have wide ranges,while the different types of the fluid inclusions existed together and their homogeneous temperatures are almost identical in the same mineralization stage,which indicates that the ore-forming process has great relation with the fluid boiling.The gas and liquid chemical compositions and the carbon,hydrogen and oxygen isotopic compositions of the fluid inclusions show that the ore-forming fluids of copper-gold deposits have the same characteristics and evolution tendency,which reflects that the ore-forming material mainly came from the magmatism.The stratigraphic component and the meteoric water may mix in ore- forming fluids in the later mineralization stages.Furthermore,with the fall of the ore-forming temperature the ratios of water and rock decreased.The characteristics of chemical composition and carbon isotopic composition of fluid inclusions indicate that CH4 may play an important role for separating copper and gold in the ore-forming process.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
基金financed by Major State Basic Research Development Program(2012CB416605)Natural Science Foundation of China(41402083)
文摘The Hujiayu Cu deposit,representative of the ＂HuBi-type＂ Cu deposits in the Zhongtiao Mountains district in the southern edge of the North China Craton,is primarily hosted in graphitebearing schists and carbonate rocks.The ore minerals comprise mainly chalcopyrite,with minor sphalerite,siegenite[（Co,Ni）_3S_4],and clausthalite[Pb（S,Se）].The gangue minerals are mainly quartz and dolomite,with minor albite.Four fluid inclusion types were recognized in the chalcopyrite-pyrite-dolomite-quartz veins,including CO_2-rich inclusions（type Ⅰ）,low-salinity,liquid-dominated,biphase aqueous inclusions（type Ⅱ）,solid-bearing aqueous inclusions（type Ⅲ）,and solid-bearing aqueous-carbonic inclusions（type Ⅳ）.Type I inclusion can be further divided into two sub-types,i.e.,monophase CO_2 inclusions（type Ⅰa） and biphase CO_2-rich inclusions（with a visible aqueous phase）,and type Ⅲ inclusion is divided into a subtype with a halite daughter mineral（type Ⅲa） and a subtype with multiple solids（type Ⅲb）.Various fluid inclusion assemblages（FIAs） were identified through petrographic observations,and were classified into four groups.The group-1 FIA,consisting of monophase CO_2 inclusions（type Ⅰa）,homogenized into the liquid phase in a large range of temperatures from-1 to 28℃,suggesting post-entrapment modification.The group-2 FIA consists of type Ⅰb,Ⅲb and Ⅳ inclusions,and is interpreted to reflect fluid immiscibility.The group-3 FIA comprises type Ⅱ and Ⅲa inclusions,and the group-4FIA consists of type Ⅱ inclusions with consistent phase ratios.The group-1 and group-2 FIAs are interpreted to be entrapped during mineralization,whereas group-3 and group-4 FIAs probably represent the post-mineralization fluids.The solid CO_2 melting temperatures range from-60.6 to56.6℃ and from-66.0 to-63.4℃ for type Ⅰa and type Ⅳ inclusions,respectively.The homogenization temperatures for type Ⅱ inclusions range from 132 to 170℃ for group-3 FIAs and115 to 219℃ for group-4 FIAs.The halite melting temperatures range from 530 to 562℃ for typeⅢ b and Ⅳ inclusions,whereas those for type Ⅲa inclusions range from 198 to 398℃.Laser Raman and SEM-EDS results show that the gas species in fluid inclusions are mainly CO_2 with minor CH_4,and the solids are dominated by calcite and halite.The calcite in the hosting marble and dolomite in the hydrothermal veins have δ^（13）C_（V-pdb） values of-0.2 to 1.2‰ and-1.2 to-6.3‰,and δ^（18）O_（v-smow） values of 14.0 to 20.8 ‰ and 13.2 to 14.3‰,respectively.The fluid inclusion and carbon-oxygen isotope data suggest that the ore-forming fluids were probably derived from metamorphic fluids,which had reacted with organic matter in sedimentary rocks or graphite and undergone phase separation at 1.4-1.8 kbar and 230-240℃,after peak metamorphism.It is proposed that the Hujiayu Cu deposit consists of two mineralization stages.The early stage mineralization,characterized by disseminated and veinlet copper sulfides,probably took place in an environment similar to sediment-hosted stratiform copper mineralization.Ore minerals formed in this precursor mineralization stage were remobilized and enriched in the late metamorphic hydrothermal stage,leading to the formation of thick quartz-dolomite-sulfides veins.
文摘The new type of copper deposits concerned with in this paper are vein copperdeposits found in the Lanping-Simao Rift Basin, Yunnan, China. As is indicated by H,O, C, S, Pb and Sr isotopes, water and mineralisers in the ore-forming fluids were derivedfrom heated meteoric waer and mantle, respectively. The metallic elements (Cu, Ag, Pb,Zn, As, Sb, Fe, REE, etc.) are characterised by a mised source from the crust and themantle.
基金the National Natural Science Foundation of China （ No. 40472052） is sincerely acknowledged.
文摘Shizishan ore-field is a nonferrous and noble metal ore-field which is most rich in copper and gold.There are many types of fluid inclusions in minerals of the deposits.The homogeneous temperatures and the salinities of the fluid inclusions in main mineralization stages have wide ranges,while the different types of the fluid inclusions existed together and their homogeneous temperatures are almost identical in the same mineralization stage,which indicates that the ore-forming process has great relation with the fluid boiling.The gas and liquid chemical compositions and the carbon,hydrogen and oxygen isotopic compositions of the fluid inclusions show that the ore-forming fluids of copper-gold deposits have the same characteristics and evolution tendency,which reflects that the ore-forming material mainly came from the magmatism.The stratigraphic component and the meteoric water may mix in ore- forming fluids in the later mineralization stages.Furthermore,with the fall of the ore-forming temperature the ratios of water and rock decreased.The characteristics of chemical composition and carbon isotopic composition of fluid inclusions indicate that CH4 may play an important role for separating copper and gold in the ore-forming process.
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。
