Abstract: Based on the field Ieconnaissance results and a great quantity of laboratery analysis data, the author presentssome new views about the Pre—Paleozoic to Paleozoic sedimentary—stratigraphic sequence of Altun Mountain as fol-lows:
lt was the Archaeozoic and Middle—Upper Proterozoic that consisted of the crystalline basement of Altun's fault—uplift zone. lts Paleozoic (cap Iock) was in a scattered distribution. Lower Ordovician stratum was overlapped unconformably on the Qingbaikou and Jixian systems, which resulted in an absence of the Cambrian, Upper Ordovician, Silurian and Lowet Carboniferous stratum occutred unconformably on the different strata of the Middle—Upper Proterozoic. The top and bottom of the Middle Carboniferous were absent in some area, while the Upper C?rboniferous anđ Lower Permian were in a continuous sedimentation.

Key words: Altun Mountain, Pre—Paleozoic, Paleozoic, Sedimentary—stratigraphic sequence, Conodonts zone, Crystalline basement, Cap rock