POSIBILITY OF SEARCHIN G GOLD DEPOSITS IN THE JUNCTION AREA OF SHAANXI, GANSU AND SICHUAN PROVINCES

The junction area of Shaanxi, Gansu and Sichuan Provinces, where broadly distributed gold deposits and gold placers, is one of the most important gold concentrated region in China. The 6 placer gold concentrated areas spacially coincide with the 6 gold deposit concentrated areas. Neotectonism in the region is frequent,so the secondary enrichment of gold is less efficient. Some placer gold grains intergrow with quartz and/or altered rocks. The fineness of some placer gold is relatively low. Some of gravels in gold placer are gold containing, up to 3×10^-6~10×10^-6. From above, it is concluded that the source material for the placer is majorly the high-Au containing geologic bodies, i.e.,the gold deposits in the region; and minorly the low-Au containing geologic bodies,i.e., strata and magmatite.Presinian Bikou group,Silurian and Devonian strata are the source beds. The structural condition and magmatic activity are favorable for the forming of gold deposits. Nearly 100 gold deposits/spots are distributed in the source bed cropped areas. There are densely distributed more than 30 geochemical and heavy mineral anomalous areas, with high peak values. After all, this region is qualified for forming more and larger gold deposits. The author then proposes the Mianxian-Wuping potential area for gold deposit searching.