1. College of Earth Sciences��Jilin University��Changchun 130061��China; 2. Qiqihar Institute of Mineral ��esources Exploration and Development��Qiqihar 161006��Heilongjiang��China

Comprehensive research was carried on the gold ore in Yuanbaoshan by geological��geophysical and geochemical exploration methods�� The results show that four ore bodies and three mineralized bodies have been found with an average Au grade of 2. 15 × 10 ^��6 �� The ore- hosting strata are the Middle Jurassic Mohe Formation�� The ore- controlling structure is nappe structure of Mohe with NEE direction�� The magnetic field strength ΔT usually is ��30 ��20 nT��while with 133. 1 nT in maximum�� The apparent polarization is 23. 58% in maximum and its av- erage is 10. 58%�� The apparent resistivity is usually below 500 Ω·m��and the highest is 1 200 Ω·m��which shows the abnormal geophysical exploration feature by low resistance and high polarization�� The gold abundance in Mohe Formation is 8. 06 ×10 ��9 ��the standard deviation is 0. 25��and the coefficient of variation is 0. 912�� The val- ue of pyrite δ 34 S is 3. 3 ×10 ^��3 ��5.3 ×10 ^��3 ��the range is 2. 5 ×10 ^��3 ��and the average is 4. 5 ×10 ^��3 ��which indi- cates the characteristics of magmatic sulfur�� The value of δ 18 O of fluid inclusion in quartz is 5. 2 × 10 ^��3 �� 9. 6 × 10 ^��3 ��the value of δD is ��125 ×10 ^��3 �� ��112 ×10 ^��3 ��and the variation range of δ 18 O and δD is comparatively big��which shows atmospheric precipitation was in the process of mineralization�� According to the abnormal features of geological and geophysical exploration��we believe that there is good prospect for explovation in Xiaojingou in western ore district (HS- - 8 combination anomaly of stream) .