1. College of Earth Sciences��Jilin University��Changchun 130061��China; 2. Chifeng Hongling Nonferrous Metal Mining Co�� ��Ltd��Chifeng 025420��Inner Mongolia��China; 3. Second Geological Mineral Exploration Institute��Linhe 015000��Inner Mongolia��China

The Pengboshan gold deposit is a quartz vein deposit in type in Carboniferous lower grade metamophic rocks�� The gold-bearing quartz veins were controlled by the faults with different directions��and most of them were distributed in the contact zone between Hercynian diorite and Carboniferous strata�� Trace element analysis revealed that the gold content in diorite was higher than that in strata rocks��indicating that diorite might provide most of the ore-forming materials for gold deposit�� The study of fluid inclusion showed that CO2-bearing and aqueous two-phase fluid inclusions developed in quartz in main mineralization stages�� The homogenization temperature and salinity of fluid inclusions were 211�� �� 289�� and 4. 51 �� 5. 23 wt%NaCl in former type and 150�� �� 320�� and 2. 1 �� 5. 1 wt%NaCl in later type��respectively�� The results showed the ore-forming fluids as a medium-temperature�� and low salinity NaCl-CO2-H2O solution��which mainly came from diorite magmas�� Pengboshan gold deposit was a medium-temperature magma-related hydrothermal deposit produced in orogenic belt environment�� The Pengboshan gold deposit is some similar to the Mulongtao type gold deposit in metallogenic age��geological and fluidcharacteristics��