The Characteristics of Devonian Sedimentary Rocks and Their Sedimentary Environments in the Keziyangluk area, Xinjiang

Key words: 
• West Kunlun /
• Devonian /
• Sedimentary rock features /
• Sedimentary /
• environment Keziyangluk

Abstract: The Devonian strain are developed on the north margin of the West Kunlun Mt. They are the oldest Paleozoic sedimentary rocks in this region and overlapped on the Middle-Upper Proterozoic strata. To the south of Monk, the Middle-Upper Devonian is well developed in the Keziyangluk area.According to the lithological features and rock associations, they can be divided into two members. The lower one is a tuffaceous graywacke carbonate rock formation, composed of tuffaceous graywacke, tuffaceous shale, pebble-bearing sandy slate and carbonate rock. The upper member is a terrigenous sandy conglomerate graywacke formation, composed of conglomerate,sandy conglomerate, lithic graywacke,quartzose graywacke, silstone, etc. The lower member is characterized by laminar bedding and horizontal bedding, indicating a steady hydrodynamic sedimentary environment. The upper member comprises torrigenous sand and Pebble sediments with clear cyclicity. Its different horizons show different sedimentary structures, such as horizontal bedding, various cross-bedding and interference ripple, indicating an unstable sedimentary water body and unsteady sedimentary factes.The studies on sedimentary structures and lithological grain features of the Middle Upper Devonian strata suggest that the lower member is formed in a bathyal-neritic sedimentary environment. and that the upper member is developed in an littoral beach inshore deltufluvial sedimentary environment.