Analysis of sedimentary characteristics and environment of loess around Urumqi
[Objective]To investigate the influence of the sedimentary environment and the altitude of the loess around Urumqi on the physico-chemical properties of the loess.[Method]The depositional char-acteristics of the loess around Urumqi were studied using statistical analysis and the Sahu sediment environ-ment discrimination formula.[Result]The grain size of loess on the east side of Urumqi is mainly com-posed of very coarse silt,coarse silt,very fine sand and medium silt,with the average volume percentage of 33.89%,22.87%,14.83%and 11.63%,respectively,and the other components are less than 7%.The av-erage particle size of loess is between 12.47～26.78 μm,the sorting coefficient is between 2～4,the skew-ness value is between-1～-0.5,and the kurtosis value is between 0.87 and 1.46,indicating that the sorting is poor,the loess particle size frequency curve is negatively skewed and tends to be normal-narrow peak dis-tribution,the fluctuation range of different profiles and different depths is large,and the climate change is sig-nificant.The overall trend of the ambient climate in Urumqi is becoming drier,with about six cycles occur-ring.The susceptibility value of loess is between 21.17×10-5～77.5×10-5 SI,with an average of 49.35×10-5 SI,with a large fluctuation range,indicating that the strength of the westerly wind circulation changes significantly in different periods,and the climate change in different periods is significant.The average or-ganic mass of loess at the depth of 0～80 cm is 1.396%,and decreases with increasing depth,which is more suitable for planting crops.[Conclusion]The sedimentary environment of the loess around Urumqi is a wind-deposited environment,and with altitude,the coarse component content of the loess is relatively higher,the average particle size increases,the sorting is better,and the magnetic susceptibility value de-creases.
NETL
NSTL
万方数据
维普
