摘要
黄土沉积是地质时期沙尘天气形成的粉尘堆积物,其粒度特征记录了粉尘搬运过程中的古大气环流格局和古环境演化信息。文中对鲁中山地北麓的青州、淄博和济南三个剖面末次盛冰期黄土样品进行了系统的粒度分析,并与黄土高原地区西峰剖面样品进行对比。结果表明:鲁中山地北麓黄土的粒度频率分布、粒度特征参数与黄土高原黄土非常相似;基于对数正态分布函数拟合后,不同地区黄土的粒度均呈现出细(C1)、中(C2)、粗(C3)三个组分,上述特征表明鲁中山地北麓黄土为风成成因的粉尘堆积物质。但反映粉尘搬运距离的粗粒组分的中值粒径和百分含量在两个地区大致相同,根据粉尘动力学原理,鲁中山地北麓黄土不可能与黄土高原黄土一样来自西北内陆荒漠地区,主要来源应为近源的黄泛平原和渤海湾陆架的松散堆积物。
The grain - size features of loess deposits document the information of atmospheric circulation pattern and paleoenvironmental evolution during dust transport processes, as the loess is the subaerial dust deposition in geological timescale. In this paper, systematic grain - size of three last glacial loess profiles, including Qing- zhou, Zibo and Jinan sections on the northern piedmonts of the central Shandong Mountainous region were ana- lyzed by Marvem Mastersizer 2000 laser particle analyzer, and comparisons with the Xifeng section of Loess Plat- eau were made. Results show that both grain - size distribution and parameters of Shandong loess are very similar with that of Loess Plateau. Based on logarithmic normal distribution function fitting, three fractions for grain size distribution of the loess from different areas were ditinguished ： fine fraction （ C1 ）, medium fraction （C2） and coarse fraction （ C3 ）. These suggest that loess of northern piedmont on the central Shandong Mountainous region is the dust accumulation material of eolian origin. However, median grain size and percentage of the coarse frac- tions, which indicates the dust transport distance, are roughly the same in different regions. According to the principles of dust dynamics, the provenance of loess in the central Shandong Mountainous region couldnt be the inland Northwest deserts, like the Loess Plateau. The dust material mainly comes from the flood plain of the Yellow River and the bald Bohai continental shelf loose deposits during the last glacial period.
出处
《干旱区资源与环境》
CSSCI
CSCD
北大核心
2014年第8期156-160,共5页
Journal of Arid Land Resources and Environment
基金
国家自然科学基金项目(41072260)
山东省自然科学基金项目(ZR2011DM012
ZR2011DL006)资助
关键词
粒度
黄土
多组分分析
鲁中山地
黄土高原
grain - size
loess
multimodal distribution analysis
the central Shandong Mountainous region, Lo- ess Plateau
