Holocene aeolian sedimentation particle size analysis and sedimentary environment in Mongolian Plateau north

The field observation and indoor particle size analysis confirm that the upper layer in northern Mongolia Shaamar segment is weak soil layer and sand layer of ancient cross-layer;central part of the ancient soil layer is sandwiched two relatively smaller size of the silty fine sand;the lower part is mainly sand intervening ancient soil layer.The analysis Shaamar profile aeolian sediments should be near the source,low-level suspension or saltation is the main transportation mode.The Selenge River near flood plains are Shaamar aeolian deposition in the main section of the source material.Sediment grain size parameters on the apparent vertical is divided into three sections,namely,grain size of the last glacial sediments is the most coarse,followed by middle and late Holocene,while grain size of the deglaciation and early Holocene sediments in the granularity is the finest.The corridor in northern Mongolia near-surface wind speed is prevalent at the last glacial period;deglaciation to the early Holocene near-surface wind speed decreases;while in the late Holocene,the average wind speed,once again increases,but slightly less than last time ice age.