A set of variegared volcaniclastic rocks outcropping in Yixiekegou on the northwest of Rude, Xinjiang, is underlied by the middle proterozic basic lavas. All the clastic fragments which constitute the volcaniclastic rocks are derived from the underlying volcanic rocks, so the mineral associations and chemical components of the volcaniclastic rocks are perfectly consistent with those of the underlying volcanic rocks. Obviously they have common characters, implying that they are closely related in origin.By comparing their chemical components, i: is found that the ophiblitic sedimentary rocks are different not only from the normal greywacke but also from the developing island arc oasalt. But there are obvious similarites between the volcaniclastic rocks and the oceanic tholeiite. This shows the sedimentary rocks possess the ophiplidc characters.The various parameters (XM, D, C, M, G) of the grain size analyses reveal that the rhythmic sedimentary cycling of the rocks is clear, the sorting of most samples is comparatively good, but the hydrodynamic is from weaker to weak. The Suhu's distinguishing parameters (<9.84) stand for that this set of sedimentary rocks are products of gravity flow in the range of deep sea fan (turbidite fan).In summary, we can determine that it was deposited in oceanic deep-water (far from the continent).