关键词: 河西走廊, 活动断层, 碳－14年龄测定, 热释光法, 土壤发育

Abstract: In this paper, the primary physical and chemical characteristics of the soil development related to Quaternary faults in the foreland region of the Yumushan mountains of the Hexi corridor, and their evolution with age have been investigated and analyzed. In six well drained soils formed in loess and alluvial proluvial parent materials of various ages (their formation ages are 5000 to 38000a ago) in this region, calcium carbonate content obviously increases with age, and so does calcium carbonate accumulation index value which represents the degree of calcic accumulation horizon development in the soil profiles. The data of the ages, the calcium carbonate contents and calcium carbonate accumlation index values of these six soil profiles were used to derive four regression equations as follows: for CaCO₃ content: Y=-37.36+3.254X(1) and for CaCO₃ accmulation index: Y=-7.19+0.298X(2) Y=-91.689+58.01 log X(3) log Y=-1.748+1.545 log X(4)Where Y is the age in 10³ years, and X is the calcium carbonate content or its accumulation index value. Test and comparative analysis indicate that the three equation (1),(2) and (4) of the above four equations fit best to the data of the study region, and their coefficients of correlation are 0.997, 0.998 and 0.992, respectively. These three quantitative relational expressions can be used tentatively in practical dating work of active faults.

Key words: Hexi corridor, Active fault, Carbon-14 dating, Thermolumincscent method, Soil development