Abstract:

The formation and evolution of dunes on both sides of river is closely related with the river. The research methods adopted such as field survey, topographic measurement and sampling, analyzed the Keriya River’s (located in the western of China) granularity, spatial distribution of the geochemical elements and dynamic factors of the near-surface sediments. The conclusions are as follows: The granularity composition of the Keriya River’s surface sediments is mainly larger than 2 φ, and the aeolian character of the granularity of the Keriya River is more obvious; Si and Al take up a large part of chemical composition, compared with the average composition of geochemical elements of the upper continental crust (UCC) or enrichment factors, all elements except Ca, Co and As are decreased to a certain degree; The characteristic of chemical elements and granularity composition of the near-surface sediments from different sections are similar to that of the upstream Pulu, indicating that one major source of the Keriya River sediments is located in kunlun mountains; From upstream to downstream, under the condition of different power, the granularity characteristic of surface material has the opposite gradient trend between the flood plain sand and terrace eolian sand; The CIA of the Keriya River Basin is below 50, and the A-CN-K ternary diagram shows that a weak chemical weathering by loss of Na and K occurred in these sediments, while other geochemical elements was in a less weathering or leaching process. The difference of the chemical weathering degree of different sections is closely related to its local climate and landform pattern; When different geomorphic units are under the same section, the granularity characteristic and chemical weathering degree have a corresponding grading law from nearby to far apart from the riverbed; The average grain size of the Keriya River is correlated with some enrichment factor of elements, and it shows that particle size controls and affects the processes of chemical weathering to a certain extent. In short, in the different spatial scales, the differentiation about the physical weathering characteristic of the sediment surface of the Keriya River essentially reflects the different separation of wind power and water power. Therefore, the research has important significance for building comprehensive discriminant index of aeolian-fluvial interactions and others aspect.

Key words: grain size, geochemical elements, sediments provenance, weathering process, the Keriya River