柴西红沟子地区中新世气候变化与侵蚀速率控制因素

柴达木盆地西部地区发育良好的新生代地层详细地记录了周围山体的变形隆升、源区风化剥蚀历史和气候环境变化过程。通过对柴达木盆地西部地区红沟子剖面中新世沉积物氯离子、硫酸根离子和碳酸盐含量测量分析，将该区17~4.8 Ma气候演化分为四个阶段: 17~16.7 Ma干旱阶段；16.7~7.4 Ma相对前期气候湿润，但气候具持续干旱特征（分别在14.7 Ma和10.7 Ma干旱加剧，8.7~7.4 Ma干湿波动加大）；7.4~5.1 Ma相对湿润，干湿波动大；5.1~4.8 Ma干旱阶段。沉积速率表明:17~16.5 Ma侵蚀速率最高、16.5~9.8 Ma侵蚀速率较低、8.7~6 Ma侵蚀速率高。该区沉积速率变化与气候变化无明显关系，而与构造活动具良好的一致性，即构造活动时期对应侵蚀速率较高或突然增高阶段，因此区域构造活动是控制红沟子地区侵蚀速率的主要因素。

The Miocene Climate Changes in Honggouzi Area of Western Qaidam Basin and Dominating Factors on Erosion Rate

Well developed Neocene strata in  the western Qaidam Basin were a detailed record of the deformation and uplift of the surrounding mountain, weathering and erosion of the provenance and the process of climate changes. Based on the measurement and analysis of the carbonate contents, chloride ion contents and sulfate radical contents of the Miocene sediment in the Honggouzi section of  the western Qaidam Basin，the climate changes in this area can be divided into the following four stages: stageⅠ(17~16.7 Ma) is a dry stage; stageⅡ(16.7~7.4 Ma) this stage is wetter than stageⅠ, but is characterized by continuous drought (the drought intensified in 14.7Ma and 10.7 Ma,  respectively and 8.7~7.4 Ma shows increased fluctuation ); stage Ⅲ（7.4~5.1 Ma）relatively humid with fluctuation；stage Ⅳ（5.1~4.8 Ma）is a dry stage. 17~16.5 Ma the erosion rate is the high; 16.5~9.8 Ma the erosion rate is relatively low and 8.7~6 Ma the erosion rate is high.The erosion rate of this area shows no obvious connection with climate, but is well consistent with tectonic activities ,namely ,the tectonic active period corresponds with the stages of the high erosion rate or the erosion rate increases dramatically. Thus, in Honggouzi area,  the regional tectonic activity is the main factor to control the erosion rate.