GRAIN-SIZE DISTRIBUTION AND GENESIS OF LOESS IN THE QINGZHOU AREA,SHANDONG
GRAIN-SIZE DISTRIBUTION AND GENESIS OF LOESS IN THE QINGZHOU AREA,SHANDONG
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发表时间：
2007
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通讯作者：
P. Shu-zhen;Gao Zhi-dong
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作者：
P. Shu-zhen;Gao Zhi-dong
鲁中山区北方的山间谷地和皮埃蒙特地带广泛分布着厚度不等的黄土沉积物。本文沿着青州地区傅家庄黄土剖面进行了系统的粒度分析，并与黄土高原第四纪黄土-古土壤样品的分析结果进行了对比，结果表明，黄土的粒度分布与黄土高原第四纪黄土-古土壤样品的粒度分布基本一致。结果表明，青州黄土的粒度分布与北京现代降尘和黄土高原黄土的粒度分布非常相似，而与河流沉积样品的粒度分布有显著差异，在整个黄土-古土壤序列中，青州黄土的粒度变化与黄土高原典型的风成黄土和古土壤相一致，黄土粒度较粗，上述结果为青州黄土的风成成因提供了沉积学方面的证据，古土壤的粒度分布特征为：青州黄土的粒度分布特征结合前人的研究表明，青州黄土的物源主要为沉积区以北黄河泛滥平原和莱州湾的海相地层，其次为远源粉砂，由高层环流从西北内陆携带的沙尘。
Loess deposits with varying thicknesses are widely distributed on intermontane valleys and piedmont zones on the northern side of the central Shandong mountainous region.A systematic grain-size analysis was performed along the Fujiazhuang loess section of the Qingzhou area.The analytic results of the samples were correlated with those of the samples taken from Quaternary loess-paleosol of the Loess Plateau,modern dust fallouts in Beijing and fluvial deposits.The results show that the grain-size distribution of the Qingzhou loess is very similar to that of modern dust fallouts in Beijing and loess of the Loess Plateau but notably different from that of the fluvial samples.In the whole loess-paleosol sequence,the grain-size variation of the Qingzhou loess is consistent with the typical eolian loess and paleosol of the Loess Plateau.The loess is coarse in size,while the paleosol is fine in size.The above-mentioned results provide evidence for the eolian origin of the Qingzhou loess in the sedimentological context.The grain-size distribution of the Qingzhou loess combined with the previous studies indicates that the main provenances of the Qingzhou loess are the marine strata exposed in the flood plain of the Yellow River and Laizhou Bay north of the sedimentary region and less commonly distal silt and dust carried by highlayer circulation from northwest inland.