青藏高原纳木错湖阶沉积的发生特征及环境指示意义

Genetic Characteristics and Environmental Implications of Sedimentary Deposits of Lake Nam Co in Tibetan Plateau

选取的21个湖相沉积物样品分别采自纳木错湖西岸塔吉古日(剖面NamCo1)和纳木错湖东北岸的干玛弄附近(剖面NamCo2)。按照其发生特征分别将剖面从顶部到底部划分为12个和9个层次,通过分析各个层次沉积物的粒径分布特征、质地组成特点、总有机碳(TOC)、总无机碳(TIC)、总碳(TC)的百分含量、酸度值(pH)、电导率(EC)、含水量等若干环境指示因子。结果显示:无论在比较两个剖面的发生特征,还是环境指示因子特征,剖面NamCo1发育程度较剖面NamCo2更加发育;通过对测年数据结果分析,两个剖面均形成于晚更新世,并且通过比较各自剖面在垂直方向上的各项环境指示因子的变化趋势,可知纳木错湖流域在晚更新世(约40kaBP)阶段发生过3次相对明显的冷暖交替过程.

In this paper, 21 lake sediments samples were collected from Tajiguri situated on the western Nam Co lake （ Profile Nam Co 1 ） and Ganmanong located in northeastern Nam Co lake （ Profile Nam Co 2） respectively. According the characteristics of the sediments genesis including the color, texture, structure, moisture, Presents of carbonates, and the roots density and so on, the two section plane are divided in to 12 layers and 9 layers separate. By analyzing some main environment implication factors consist of the grain size composition, total organic carbon（ TOC）, total inorganic carbon（TIC）, total carbon（TC）, pH value, electricity conductivity （EC）, and water content, the results show that ： the genesis degree of Profile Nam Co 1 is much better than that of Profile Nam Co 2 ; on the bases of aging data, both the two profiles formed from Late Pleistocene and indicated three times cold-warm alternations periods since about 40ka BP.