The Study Of Quaternary Stratigraphic Sequence In Yabulai Mountain Of Alxa, Inner Mongolian Autonomous Region

The research area locates in the Alxa of Inner Mongolian, northwest of China,having not well on natural conditions and transportation and lacking detailedQuaternary stratigraphic data. So the Quaternary layers, where in Yabulai Mountain ofAlxa area, are objects of study in this paper. By collecting and analyzing materials inpast, and combining new data of grain size that was obtained in study area section, asgranularity, OSL, ESR, meanwhile, according to Quaternary sediments’ causes types,lithology and lithofacies, taking advantage of stratigraphy, geochronology,geomorphology and so on, systematically compared and divided Quaternary layers,and established Quaternary stratigraphic sequence column in the area.The characteristics of Quaternary layers were summarized as follows:1.Distribution, the distribution of lower Pleistocene and middle Pleistocene layerswere limited, and most distributed in valley, however, upper Pleistocene and Holocenelayers wildly distributed, and were discovered in Piedmont and ditches. There arefourteen, twenty-one, ten and four sections in the layers.2.Cause types, lower Pleistocene was a set of alluvial flood gravel andsand-gravel layers, and has the components for basalt, phyllite, and so on, generalsorting, developing oblique bedding, good cementation, and hard texture; middlePleistocene was a set of gray and deep-gray alluvial flood gravel and sand layers, andhas the major components for basalt, poor cementation, and good cementation in littlelayers; upper Pleistocene was a set of alluvial flood gravel layers, friable cementation,and has the components for slate, phyllite; Holocene was a set of flood and alluvialflood gravel and sand layers and has the major components for basalt, poorcementation.3. Stratigraphic characteristics, by comparing the area to the northwest area ofChina in stratigraphic characteristics at the same time, I concluded that the sedimentsfeatures fits the northwest area in Quaternary. Finally, combing the geomorphiccharacteristics, I established Quaternary stratigraphic sequence column in the area.