Abstract:

A high solution analysis was carried out on loess particle at Qidingshan through screen method via SA-CP3 (a granularity analysis instrument made in Japan) and TL chronology, with the results that the loess granularity is dominantly coarse, coarse silt 4~6φ about 26.39~48.33%, a less clay (0.05~2.44%). At Malan, the loess granularity concentrates on two grades, 2~4φand 4~6φ, with coarse silt slightly more than fine sand. At Lishi, the loess granularity is dominantly 4~6φ. This paper, based on a comprehensive statistical analysis on sediment granularity parameters, indicates that there has been a big difference with inland winding loess since the middle Pleistocene. The loess sediment in Qidingshan is derived primary from a nearby source and secondarily from far source.

Key words:

loess; granularity analysis; sedimentary environment; Qidingshan

摘要：

运用筛析法和日本产光透式离心粒度分析仪（SA-CP3）,结合热释光（TL）年代学，对大连市七顶山黄土粒度进行高分辨率分析。结果表明：黄土粒度成分偏粗，粒级集中在4～6 φ（26.39%～48.33%）的粗粉砂级，粘粒含量少（0.05%～2.44%）;马兰黄土粒级集中在2～4 φ和4～6 φ，其中粗粉砂比细砂含量稍多；离石黄土集中在4～6 φ的粗粉砂粒级范围内。采用沉积物粒度参数的综合统计分析得出：中更新世以来本区黄土与内陆风成黄土沉积环境存在明显差异，本区黄土沉积是以近源为主、远源为辅的双物源沉积模式。

关键词: 黄土；粒度分析；沉积环境；七顶山