Grain-size Characteristics of Early-Middle Pleistocene Lacustrine Sediments and Their Indication of Sedimentary Environment in the Southern Bohai Sea
LV Wen-zhe
YI Liang
FU Teng-fei
CHEN Guang-quan
XU Xing-yong
YU Hong-jun
Abstract：Grain-size analysis of the lower 47 m sediments in Borehole Lz908 drilled at the southern coast of the Laizhou Bay reveals that the mean grain diameter of the sediments ranges from 3.2 Φ to 7.4 Φ,indicating that they are mainly composed of clayey silt,followed by a small amount of sandy silt and silty sand.The sorting of the sediments is poor,with the sorting coefficient being 1.1~2.5.The skewness and the kurtosis of the sediments are mostly 0.7~2.4 and 1.9~3.4,respectively,showing a positive and/or very positive skewness and a flat and/or normal distribution,respectively.The comprehensive analyses of grain size compositions,grain-size C-M diagrams and grain-size structural scatter diagrams of the sediments indicate that compared with those in the upper part of the borehole,the sediments in the lower part of the borehole reflect a relatively lower-energy and more stable hydrodynamic environment,and that the southern coastal area of the Laizhou Bay was in a sedimentary environment in which the shallow and deep lacustrine facies were formed alternately in the Early-Middle Pleistocene.It is,therefore,considered that the grain size characteristics of the sediments in the southern coastal regions of the Laizhou Bay can be used effectively for determining the sedimentary environment and extracting the paleoenvironmental information,and could be the important proxies of sedimentary environment.
Keywords：southern coast of the Laizhou Baygrain sizesedimentary environmentlacustrine facies
Publication Date：2017-01-01
Online Publishing Date：2026-05-22(First online date of this platform, not the publication date of the document)
Pages：9( 34-42 )