前湖湾晚第四纪沉积物粒度及磁化率特征分析  

Characteristic analysis of the grain size and the magnetic susceptibility on the late quaternary sedimentary strata over Qianhu Bay

作　　者：刘巍[1] 俞鸣同[1] 龚正权[1] 陈有喜[1] 

机构地区：[1]福建师范大学地理科学学院,福州350007

出　　处：《安全与环境学报》2009年第2期68-71,共4页Journal of Safety and Environment

基　　金：福建省教育厅课题(JA03169);福建师范大学地理科学学院研究生科研创新基金项目

摘　　要：为进一步探索福建闽南沿海晚第四纪环境及气候演变的规律,选取漳浦前湖湾的海岸剖面以及海岸、海滩两个钻孔作为代表剖面,并对剖面(D2)进行间距10 cm刻槽,共采样70个,对钻孔岩芯进行10 cm的等间距采样,其中剖面延续性钻孔CHHA采样72个,海滩对比钻孔CHHT采样38个。另外选取当地海岸的风砂堆积物、海滩沉积物、河流沉积物作为典型沉积环境判别的参考。进行两项实验:1)对所有样本进行粒度测试;2)对所有样本进行高低频磁化率的测试。通过实验获得了距今4万年以来的沉积物粒度数据和相应时期的磁化率数据。研究表明:1)当地气候形成经历了湿热、干冷、更干冷、湿热4个大的冷暖交替时期;2)前湖湾的环境经历了由河流沉积环境转为海滩沉积环境,再转为风砂堆积环境的变迁;3)古树林很可能原生于此,后因海面上涨而被现代海滩沉积覆盖。This paper is to report our characteristic analysis of the grain size and the magnetic susceptibility on the late quaternary sedimentary strata over the continuous profile of Qianhu Bay by drilling holes on the beach near the coast area. The goal of our research is to trace the evolutional environmental change of southeastern Fujian since the above said age from the analysis of the typical profiles so as to discover the evolutionary regularity of the local environment and the effect of climate on the bay. In doing so, we have prepared 10 cm-equal geologically spaced samplings from the profile （D2, 70 cuts in total）, and 10 cm-equally spaced samplings in the drilling holes （CHHA, 72 cuts in total; CHHT, 38 cuts in total）. To further our research, particular attention has been paid to selecting the eolian sand deposits and beach, fluvial deposits as reference in hoping to identify the sedimentary environment in the area. In proceeding with our research, we have accomplished two kinds of experimental investigation： the first is to test the grain size to all the samples with the Mastersizer 2000 laser grain-size instrument while the second is to test the magnetic susceptibility of the same samples with Bartington MS2 magnetic susceptibility instrument. The first one has made us clear about the data on the grain-size changes of the sand sediment for the past 40 000 years BP whereas the second one has made us clear of the changes of the magnetic susceptibility during the same period. We used the data to establish grain size-series and magnetic susceptibility-series according to the depth. And, finally, the data processing helps us to draw a conclusion that the local climate is likely to have experienced four periods of cold-to-warm alternating changes during the long age, such as humid-hot stage, dry-cold stage, dryer-colder stage and again humid-hot stage. Furthermore, the environment of Qianhu Bay is likely tO have experienced a fluvial deposit environment, a beach sediment environment and a modern beach sa

关 键 词：自然地理学 晚第四纪沉积层 漳浦 磁化率 粒度 

分 类 号：K903[历史地理—人文地理学]