粒度分布的端元建模分析及检验:以“吉兰泰—河套”盆地西部DK-12钻孔晚第四纪沉积物为例

摘要

端元建模分析能够从复杂的多峰分布特征的沉积物中提取出具有不同沉积动力过程的端元,但是,由于沉积物的粒度分布还受到沉积环境等多种因素的影响,该方法的有效性及获得的端元组分的地质意义有待其他环境代用指标的进一步检验.以位于“吉兰泰—河套”盆地西部磴口次级隆起区的DK-12钻孔晚第四纪沉积物为例,采用BEMMA算法对该钻孔沉积物的粒度资料进行了端元建模分析,并以黏土矿物组合和前人的孢粉组合数据作为检验指标,结合该地区的区域地质背景,对获得的4个端元进行了综合检验分析,认为获得的沉积物粒度端元具有明确的地质意义,其中EM 1为远源粉尘、EM 2为近源的风成沙、EM 3和EM 4为河流冲积沙.%End-member modeling analysis is beneficial to extract the end-members with different transporting dynamics from sediments characterized by complex multimodal distribution.However,because the grain-size distribution of sediments is affected by many factors besides depositional environment,the effectiveness of this method and the geological significance of each end-member need to be tested.In this paper,the BEMMA algorithm is used to analyze grain size data of samples from the Borehole DK-12 obtained in the Dengkou sub-uplift at the western Jilantai-Hetao Basin.Four end-members are recognized including remote dust (EM 1),aeolian sand (EM 2),and fluvial sand (EM 3 and EM 4).