44ka以来福州盆地红土的沉积地球化学特征  

Geochemistry Characteristics of Red Earth Sedimentation since 44ka in Fuzhou Intermountane Basin

作　　者：靳建辉[1,2,3] 李志忠[1,2,3] JIN Jianhui LI Zhizhong(Institute of Geography, Fujian Normal University, Fuzhou 350007, China School of Geography Science, Fujian Normal University, Fuzhou 350007, China Key Laboratory of Humid Subtropical Ecosystem and Geography,Ministry of Education,Fuzhou 350007 ,China)

机构地区：[1]福建师范大学地理研究所,福州350007 [2]福建师范大学地理科学学院,福州350007 [3]湿润亚热带生态-地理过程教育部重点实验室,福州350007

出　　处：《山地学报》2016年第6期690-697,共8页Mountain Research

基　　金：国家自然科学基金(41301012,41271031);福建省自然科学基金(2013J01153)~~

摘　　要：基于福州盆地MB红土剖面所揭示的地层岩性和光释光样品的年龄结果,以及对剖面地化元素的系统分析结果,对剖面所揭示的地层化学风化特征及其区域气候变化特征进行探讨,结果显示:1.福州盆地的坡积红土沉积始于晚更新世中期,止于全新世晚期;2.马保剖面整体的化学风化特征变异主要受自然因素所控制,红土表层受化学风化和流水搬运共同作用的影响。末次寒冷期以来福州盆地古地理环境经历了明显的阶段性变化,且与深海氧同位素阶段有较好对应关系;3.氧同位素1(MIS1)阶段在福州盆地红土中的记录难以进行高分辨率提取,期间可能存在沉积间断,间断时间约为2.3ka。Based on the age of optically stimulated luminescence （OSL） and the stratigraphic lithology of Mabao （MB） clay profile in Fuzhou intermountane basin, this paper mainly analyzed the results of geochemical elements. Meanwhile we discussed the chemical weathering features and regional climate change characteristics. The result showed that 1 ） the age of Diluvial clay in Fuzhou intermountane basin was from middle stage of Late Pleistocene to Late Holocene. This period was roughly corresponding to the first to the third stage of Marine Oxygen Isotope （ MIS1 - 3 ）. 2） The variation of chemical weathering characteristics of Mabao （MB） profile was controlled by nature factors, and the topsoil of MB profile was undergone a combined impact of chemical weathering and trans- porting action of flowing water. A1, Fe accumulation and the local intense eluviation represented a warm humid chemical weathering environment of Fuzhou intermountane basin since 44 ka. The information of environmental changes recorded in the MB clay profile can roughly reestablish the climate change process on the orbital timescale. The paleoenvironment of Fuzhou basin had undergone different phases, which corresponded to marine oxygen iso- tope stages （MIS） since the last glacial period. In the first period （44.1 ka - 23.0 ka）, the regional climate was warm and humid as a whole, and after 25 ka before with vegetation of bushwood and meadowland. In the present, the climate environment turned to generally colder second period （23.0 ka - 14.3 ka）, the climate condition mainly dominated by warm and cool reflected by the changes of geochemical elements and elements ratios in Fuzhou intermountane basin. The period of 18 - 15 ka before present was a typical period with most prominent change. There was a sharp decline in Fuzhou intermountane basin temperatures, which led to tropical animals migrated southward and finally disappeared in Fujian area. And in the last period （ 14.3 ka - now）, the climatic character- istics main

关 键 词：福州盆地 红土 地球化学 古气候 第四纪 

分 类 号：P92[天文地球—自然地理学]