1. College of Earth Sciences��Jilin University��Changchun 130061��China; 2. Third Gold Geological Party of CAPF��Harbin 150086��China

Sanshier'zhan gold deposit is located in the northeastern Erguna rising part on the edge of upper Heilongjiang Basin of fault subsidence�� The gold ores are yielded in medium-grained sandstone in Ershi'erzhan Formation�� Magmatic rocks are mainly with diorite and granite which is closely related to mineralization�� Nine alteration zones and ten gold ore bodies were discovered within the mining area�� The ore bodies ranges 600 �� 1 290 m long by 1. 86 �� 5. 70 m wide�� The gold grade is ( 1. 31 �� 2. 44) × 10 ^��6 �� According to tectonic environment discrimination diagrams��granite in this mining area is orogenic granite��showing some geochemical characteristics of that from island arc or continental margin environment related to the subduction zone�� Diorite shows the characteristics of that from island arc or active continental margin environment�� Sandstone in Ershierzhan Formation shows the characteristics of that from continental island arc�� At the end of Middle Jurassic--early Late Jurassic��the Pacific Plate had obliquely subducted the lower part of the Siberian Plate��which leads the gold element started enrichment in Ershierzhan Formation for the first time��and provided a favorable space for mineralization�� In late Late Jurassic�� magmatic fluid interacted with the mantle and caused the mantle metal sulfide oxidation decomposition and brought to the superficial ground�� It finally enriched and mineralized in favorable metallogenic parts��