Genesis and Geological and Geochemical Characteristics of Qixia Gold Deposit, Shandong, China  

作　　者：徐红 

出　　处：《Chinese Journal Of Geochemistry》1998年第4期338-345,共8页中国地球化学学报

摘　　要：The Qixia gold deposit is one of the important quartz vein-type deposits hosted inmetamorphic rocks in the east of Shandong, China. Compositionally the wolframite which isassociated with gold mineralization in the deposit is rich in iron, but poor in manganese, showing that this mineral crystallized from hydrothermal solution at low temperature. The temperatures at the main metallogenic stage of the Qixia gold deposit are Within the range of 160 -270t. The gaseous phases in fluid inclusions are dominated by H2O and CO2, while Na+,Ca2+ and Cl- are the major species in the fluid phase with K+ and F- present in relativelysmall amounts. The salinities of fluids are 4. 2 wt% - 8. 0 wt% NaCl equiv. Meanwhile, thefluid is characterized by either Ca2+ > Na+ > K+ (in five samples) or Na+ > Ca2 + > K+ (in twosamples), quite similar to the composition of ore-forming fluid derived from meteoric water.Primary data on the hydrogen and oxygen isotopic compositions of the ore-forming fluid fallwithin a wide range: δ%H2o = - 56‰-95‰ and δ18OH2O=- 3.6‰-4. 5‰ relative toSMOW. These isotopic values fully reflect the distribution features of meteoric water which hasexchanged with the metamorphic rocks of the Jiaodong Group at different temperatures and W/R ratios, and the metallogenic process is characterized by low W/R ratios. The Rb-Sr isochronage of the Qixia gold deposit is 125. 8 ± 1. 7 Ma, with (87Sr/86Sr) being 0. 7168, and the timeinterval between the gold deposit and its country rocks (granite or metamoprhic rocks) is verylarge. The formation Of the Qiaxia gold deposit is directly related to the evolution of geologicalhistory in eastern Shandong, and a genetic model in which the deep convective circulating meteoric water reacts with the country rocks can be used to explain the metallogenic mechanism ofthe deposit.The Qixia gold deposit is one of the important quartz vein-type deposits hosted inmetamorphic rocks in the east of Shandong, China. Compositionally the wolframite which isassociated with gold mineralization in the deposit is rich in iron, but poor in manganese, showing that this mineral crystallized from hydrothermal solution at low temperature. The temperatures at the main metallogenic stage of the Qixia gold deposit are Within the range of 160 -270t. The gaseous phases in fluid inclusions are dominated by H2O and CO2, while Na+,Ca2+ and Cl- are the major species in the fluid phase with K+ and F- present in relativelysmall amounts. The salinities of fluids are 4. 2 wt% - 8. 0 wt% NaCl equiv. Meanwhile, thefluid is characterized by either Ca2+ > Na+ > K+ (in five samples) or Na+ > Ca2 + > K+ (in twosamples), quite similar to the composition of ore-forming fluid derived from meteoric water.Primary data on the hydrogen and oxygen isotopic compositions of the ore-forming fluid fallwithin a wide range: δ%H2o = - 56‰-95‰ and δ18OH2O=- 3.6‰-4. 5‰ relative toSMOW. These isotopic values fully reflect the distribution features of meteoric water which hasexchanged with the metamorphic rocks of the Jiaodong Group at different temperatures and W/R ratios, and the metallogenic process is characterized by low W/R ratios. The Rb-Sr isochronage of the Qixia gold deposit is 125. 8 ± 1. 7 Ma, with (87Sr/86Sr) being 0. 7168, and the timeinterval between the gold deposit and its country rocks (granite or metamoprhic rocks) is verylarge. The formation Of the Qiaxia gold deposit is directly related to the evolution of geologicalhistory in eastern Shandong, and a genetic model in which the deep convective circulating meteoric water reacts with the country rocks can be used to explain the metallogenic mechanism ofthe deposit.

关 键 词：氢同位素 氧同位素 锶同位素 山东 石英脉型金矿床 钨锰铁矿 流体包裹体 山东 胶东地区 成矿机制 

分 类 号：P618.51[天文地球—矿床学] P597[天文地球—地质学]