The authors presented geochronology and geochemical data of diorites from Nancha gold deposit in Tonghua region, with the aim to constraining its formation age, magma source and tectonic setting. LA-ICP-MS U-Pb dating...The authors presented geochronology and geochemical data of diorites from Nancha gold deposit in Tonghua region, with the aim to constraining its formation age, magma source and tectonic setting. LA-ICP-MS U-Pb dating results of zircons from the diorites indicate that the rocks were formed in the Middle Jurassic （171 ±2 Ma, MSWD = 1. 19）. Geochemically, these rocks have Si02 concentrations of 52. 52%-54. 90%,K20 of 2. 14%-3.84% , Na20 of 3. 17%-3. 35% , MgO of 7. 43%-9. 34% and high Mg# of 68. 57-72. 57. These rocks are characterized by enrichment in large ion lithophile elements（ LILE,such as K, Ba, Rb and Sr） and light rare earth elements （ LREE） , relatively depletion in high field strength elements （ HFSE, such as Ta, Nb, Ti and Zr） , and heavy rare earth elements （HREE）. These characteristics suggest that primary magma of the rocks were derived from the partial melting of mantle with miner crustal contamination, which may related to partial melting of mantle wedge by addition of sediment melt from subducting oceanic crust. Based on former and present studies, the authors consider that the Nancha ore deposit high-Mg diorites were formed in compres- sional structural setting which is similar to volcanic arc. It could be related to the subduction of the Paleo-Paci- fic plate beneath the Eurasian continent.展开更多
The Laoling metallogenic belt is very important for precious and non-ferrous metal deposits in Jilin province, and the Nancha gold deposit found and explored in recent years in the metallogenic belt is the most repres...The Laoling metallogenic belt is very important for precious and non-ferrous metal deposits in Jilin province, and the Nancha gold deposit found and explored in recent years in the metallogenic belt is the most representative one in the belt. The geological controls of the deposit,and the geophysical and geochemical ore searching indicators are summarized, and a synthetic exploration model, involving data from geology, geophysics and geochemistry and so on, is set up in the paper based on the study on the geological controls of the ores, on the measurement of geophysical properties of the ores and host rocks, on the observation of geophysical field around the mineralized district and on the research of the geochemical characte^ristics of the deposit. It is believed to be of significance to the exploration of the similar deposits in the metallogenic belt.展开更多
吉林南岔金矿床地处辽吉裂谷系老岭隆起带西南端,为20世纪80年代发现的一中型构造蚀变岩型矿床,区内金矿化带(体)产于中元古界老岭群珍珠门组白云质大理岩与花山组片岩接触过渡部位,其热液成矿作用经历了:Ⅰ黄铁矿石英阶段;Ⅱ黄铁矿黄...吉林南岔金矿床地处辽吉裂谷系老岭隆起带西南端,为20世纪80年代发现的一中型构造蚀变岩型矿床,区内金矿化带(体)产于中元古界老岭群珍珠门组白云质大理岩与花山组片岩接触过渡部位,其热液成矿作用经历了:Ⅰ黄铁矿石英阶段;Ⅱ黄铁矿黄铜矿石英阶段;Ⅲ少硫化物碳酸盐石英阶段。流体包裹体研究表明,各阶段矿石中主要发育气液两相包裹体。Ⅰ阶段包裹体均一温度180~260℃,盐度为4.78%~9.47%Nacl;Ⅲ阶段包裹体均一温度为164~188℃,盐度为2.76%~4.94%Nacl,表明成矿流体为中低温、低盐度NaCl H 2O体系热液。氢氧同位素研究结果表明,Ⅰ阶段包裹体水δ18 O H2O SMOW値为3.3‰~5.3‰,δD V SMOW值变化范围为-90.5‰^-92.6‰;Ⅲ阶段包裹体水δ18 O H2O SMOW値为-6.5‰^-8.2‰,δD V SMOW值为-105.4‰^-117.7‰,反映Ⅰ阶段成矿流体主要来源于岩浆热液,Ⅲ阶段成矿流体多来源于大气降水。岩浆来源流体温度降低及与大气降水混合可能是金沉淀成矿的主要机制。展开更多
文摘The authors presented geochronology and geochemical data of diorites from Nancha gold deposit in Tonghua region, with the aim to constraining its formation age, magma source and tectonic setting. LA-ICP-MS U-Pb dating results of zircons from the diorites indicate that the rocks were formed in the Middle Jurassic （171 ±2 Ma, MSWD = 1. 19）. Geochemically, these rocks have Si02 concentrations of 52. 52%-54. 90%,K20 of 2. 14%-3.84% , Na20 of 3. 17%-3. 35% , MgO of 7. 43%-9. 34% and high Mg# of 68. 57-72. 57. These rocks are characterized by enrichment in large ion lithophile elements（ LILE,such as K, Ba, Rb and Sr） and light rare earth elements （ LREE） , relatively depletion in high field strength elements （ HFSE, such as Ta, Nb, Ti and Zr） , and heavy rare earth elements （HREE）. These characteristics suggest that primary magma of the rocks were derived from the partial melting of mantle with miner crustal contamination, which may related to partial melting of mantle wedge by addition of sediment melt from subducting oceanic crust. Based on former and present studies, the authors consider that the Nancha ore deposit high-Mg diorites were formed in compres- sional structural setting which is similar to volcanic arc. It could be related to the subduction of the Paleo-Paci- fic plate beneath the Eurasian continent.
文摘The Laoling metallogenic belt is very important for precious and non-ferrous metal deposits in Jilin province, and the Nancha gold deposit found and explored in recent years in the metallogenic belt is the most representative one in the belt. The geological controls of the deposit,and the geophysical and geochemical ore searching indicators are summarized, and a synthetic exploration model, involving data from geology, geophysics and geochemistry and so on, is set up in the paper based on the study on the geological controls of the ores, on the measurement of geophysical properties of the ores and host rocks, on the observation of geophysical field around the mineralized district and on the research of the geochemical characte^ristics of the deposit. It is believed to be of significance to the exploration of the similar deposits in the metallogenic belt.
文摘吉林南岔金矿床地处辽吉裂谷系老岭隆起带西南端,为20世纪80年代发现的一中型构造蚀变岩型矿床,区内金矿化带(体)产于中元古界老岭群珍珠门组白云质大理岩与花山组片岩接触过渡部位,其热液成矿作用经历了:Ⅰ黄铁矿石英阶段;Ⅱ黄铁矿黄铜矿石英阶段;Ⅲ少硫化物碳酸盐石英阶段。流体包裹体研究表明,各阶段矿石中主要发育气液两相包裹体。Ⅰ阶段包裹体均一温度180~260℃,盐度为4.78%~9.47%Nacl;Ⅲ阶段包裹体均一温度为164~188℃,盐度为2.76%~4.94%Nacl,表明成矿流体为中低温、低盐度NaCl H 2O体系热液。氢氧同位素研究结果表明,Ⅰ阶段包裹体水δ18 O H2O SMOW値为3.3‰~5.3‰,δD V SMOW值变化范围为-90.5‰^-92.6‰;Ⅲ阶段包裹体水δ18 O H2O SMOW値为-6.5‰^-8.2‰,δD V SMOW值为-105.4‰^-117.7‰,反映Ⅰ阶段成矿流体主要来源于岩浆热液,Ⅲ阶段成矿流体多来源于大气降水。岩浆来源流体温度降低及与大气降水混合可能是金沉淀成矿的主要机制。
