山东青州黄土的地层年代及其物质来源研究  

Magnetostratigraphy and provenance of the Qingzhou loess in Shandong Province

作　　者：彭淑贞[1,2] 朱丽君[2] 肖国桥[3] 乔彦松[4] 高志东[2] 陈栋栋[2] 

机构地区：[1]泰山学院旅游与资源环境学院,山东泰安271021 [2]山西师范大学城市与环境科学学院,山西临汾041000 [3]中国地质大学生物与环境地质教育部重点实验室,湖北武汉430074 [4]中国地质科学院地质力学研究所,北京100081

出　　处：《干旱区地理》2010年第6期947-953,共7页Arid Land Geography

基　　金：国家自然科学基金(41072260和40402026)

摘　　要：为探讨山东青州黄土的地层年代,对傅家庄黄土剖面进行了系统的磁性地层学研究,并对剖面上部进行了光释光测年和粘土矿物分析。结果表明:青州黄土发育的年代未达到布容/松山界限,结合光释光测年推断,其底界年龄大致在500 ka前后,与长江下游地区的下蜀黄土起源时代接近,均对应于中更新世全球急剧变冷的时期;粘土矿物的分析结果进一步支持青州黄土主要来源于冰期裸露的渤海湾陆架和黄泛平原的松散堆积物。上述结果表明,青州黄土的起源时代不仅与区域性环境条件有关,而且与中更新世以来全球环境变化的背景具有密切联系。Loess deposits with varying thicknesses zones on the northern side of the central Shandong clear. The paper dated the Qingzhou loess profile are widely distributed on intermontane valleys and piedmont mountainous region. Its basal ages and dust resources are not with magnetostratigraphic and optical stimulated luminescence （OSL） methods and further investigated its main provenances with the mineralogical methods. The magnetostrati- graphic results show that the Brunhes/Matuyama （B/M） reversal boundary is not recognized, suggesting a basal age of younger than O. 78 Ma. Extrapolations by sedimentation rates based on the upper part depositional rate from the OSL age yield a basal age of about 0.5 Ma. Until now, older loess deposits have been no reported on the north- ern side of the central Shandong mountainous region. The results of the paper indicate that the dust deposits in this area may be origin since the Middle Pleistocene. The basal age of Qingzhou loess is approximately synchronous with the Xiashu loess in the middle - lower researches of Yangtze River. Major components of clay minerals in the Qing- zhou profile are dominated by illite. Other clay mineral compositions are mainly smectite, chlorite and kaolinite, which is similar with that of the Xifeng loess in the Loess Plateau. However, contents of smectite and the ratios of illite and kaolinite in Qingzhou loess samples are higher than those in the Xifeng loess samples of the Loess Plateau, indicating that the loess in the northern side of the central Shandong mountainous regions has different sources from the loess deposits on the Loess Plateau. Clay mineral analysis further reinforces the earlier conclusion that the ma- rine strata exposed in the Laizhou Bay and the flood plain of the lower Yellow River during the glacial time are the main material sources for the Qingzhou loess deposits, which is an indication of the local acidification of the lower Yellow River. Dust deposition in the central Shandong mountainous regions started at around 0.5

关 键 词：黄土 磁性地层学 沉积学 物源 青州 

分 类 号：P642.131[天文地球—工程地质学]