Using the particle data obtained from the Holocene soil profile at LGT, JYC sites in the Guanzhong area and at PLG, SBLH sites in the Zhengzhou, this article attempts to illustrate the material source of Zhengzhou loess and its environmental significance.The micromorphology was observed under a petrographic microscope, and its image was quantificationally measured by NIKON NIS-ELments BR2.2 software.Particle size distribution was determined by a Malvern Mastersizer-S and with Na4P2O7 as a dispersant.Micromorphological observation of the thin sections shows that the grain-shape of Zhengzhou loess is characterized by sub-round or round, with higher length/width ratio, and that of the Guanzhong loess by sub-angular or angular, with strip, triangular and irregular shapes.Comparison with the Guanzhong loess, the coarse of Zhengzhou loess is characterized by higher Length, Area, EqDiameter, Perimeter, Elongation and Roundness, and K1,K2,K3,K4 value are more than 1.It suggest that the particle in the Zhengzhou loess has higher roundness and sphericity and has gone through stronger hydraulic abrasion.The assemblage of minerals in both loess is mainly composed of Q and Pl.However, Q+Pl content, Q/Pl ratio and C/F10μm ratio are clear higher in Zhengzhou loess than in Guanzhong loess.Research result shows that particle-size of both loess falls in the same range, within particle-size range of aeloian, but peak value of particle-size of Zhengzhou loess ranges in 50-80 μm with steep particle-size curve and that of Guanzhong loess is in 20-40 μm with slow particle-size curve.All the results of this study suggest that Zhengzhou loess is aeolian, which has synchronously both aeolian and alluvium features.However its material source differs from Guanzhong loess, and it came from various loose river sediments at the Huanghe (Yellow) River alluvial fan in the east of Mengjin and transported by northeastern wind.
PANG Jiang-Li, HUANG Chun-Chang, CHA Xiao-Chun, ZHU Yi-Zhi
. Micromorphological Features of Particlesof Holocence Loess at Zhengzhou Areas, China and Their Environmental Significance[J]. SCIENTIA GEOGRAPHICA SINICA, 2008
, 28(5)
: 683
-687
.
DOI: 10.13249/j.cnki.sgs.2008.05.683
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