小干沟金矿点位于内蒙古呼伦贝尔盟额尔古纳市吉拉林砂金矿西约５ｋｍ处．小干沟金矿点的发现（内蒙古地勘局第六勘察院，１９９６）为在该区大面积分布的海西期花岗岩中寻找岩金矿及探索吉拉林等砂金矿的形成具有重要意义．笔者在小干沟金矿点发现了侏罗纪末期侵位的二长岩，并初步确定该金矿化与二长岩关系密切． Xiaogang GOLD gold deposit is located about 5km west of the Gelalinxiao gold deposit in Erguna, Inner Mongolia. The discovery of the Xiaogangou gold deposit (No. 6 Institute of Geological Exploration, Inner Mongolia Bureau of Geology and Prospecting, 1996) is of great importance in the search for rock gold deposits in the Hercynian granite with large area in this area and in the exploration for the formation of gold deposits such as Geralin significance. The author discovered the emplacement of the Jurassic end-stage monzonite at Xiaoganggou gold deposit and determined that the gold mineralization is closely related to the ductile rock.