Quanshuicun Fm

Its base marked by andesite is distinguished from the underlying Changcai Fm marked by tuffaceous conglomerate and shows a conformable contact with the latter.

Its top marked by gray purple andesite lies unconformably under the conglomerate of the overlying Dalazi Fm.

The present formation occurs in the Chechangzi- Songxiaping and Fudong-Changcai areas of the Helong county, and exposed sporadically near Duhuangzi of Wangqing. In the Helong basin, it varies considerably in lithology laterally and longitudinally and is 295 m thick at the Quanshui village, and northward to Jinchanggou only 33 m thick. It increases in the amount of pyroclastic rocks and decreases in the amount of lava northward and southward. In the Duhuangzi basin, it is represented by gray green and gray purple andesitic tuff lava and andesitic breccia tuff lava, with a thickness of 357 m. In the Yimianshan basin, it is represented by moderately acid tuff lava and andesite, with a thickness of 707.5 m. In the Luozigou basin, the lower part of the formation is built up by moderately basic olivine basalt and pyroxene andesite, while the upper part acid lava and pyroclastic rocks, ranging from 300 to 600 m in thickness. The Jilin Regional Geological Survey Team (1984) correlated the Quanshuicun Formation with the Dongshan Fm, which was assigned to the Quanshuicun Formation during the stratigraphic sorting in 1994. In the Diyingou basin, the Quanshuigou Formation is composed of basalt andesite, andesite and pyroxene andesite, with a thickness of more than 880 m.