| Abstract: Based on the field investigation and systemic samples collected at Majuangou profile, selected 67 samples by equal intervals of 1m to XRD mineral component analysis, establish characteristic of minerals and paleoenvironment relationship of Nihewan basin in the early Pleistocene. The results show that the sedimentary minerals were major component of detrital minerals and carbonate minerals. Detrital minerals were dominated the profile sedimentary mineral and composition with quartz,sodium feldspar, dolomite and plagioclase, the mean values of 38.78%, 17.16%, 29.63%, and 4.10%, respectively. Each of the detrital minerals were hardly have the correlation.The carbonate minerals have low content in the section and major component by the calcite and dolomite, with the content of 4.72% and 3.59%, respectively. It has a few of aragonite in the profile, the source of aragonite was from the mollusk shells. Coupled with thermomagnetic analysis, the grayish-green silt samples generally have higher contents of chlorite and more enhanced magnetic susceptibility after heating than the grayish-brown silts samples. In addition, the contents of chlorite were closely positive correlation with the chemical weathering in the study areas, supported that the variation characteristics of thermo-magnetic analysis (especially k-t curve) can be used to reflect the intensity variation of chemical weathering in the Nihewan Basin. It was important paleoenvironmental significance. |
