150～20ka BP福建东部平潭岛海岸风成沉积的粒度特征及其环境意义  

Grain size Characteristics of Coastal Aeolian Sediments in the Pingtan Island of Fujian,China,and their Implications for the PaleoEnvironment from 150ka BP to 20ka BP

作　　者：温小浩[1] 李保生[1,2] 孟洁[1] 杨庆江[1] 郑琰明[3] 牛东风[1] 王丰年[4] 蔡瑜杭 

机构地区：[1]华南师范大学地理科学学院,广东广州510631 [2]中国科学院地球环境研究所黄土与第四纪地质国家重点实验室,陕西西安710075 [3]韩山师范学院地理与旅游管理学院,广东潮州521041 [4]惠州学院旅游管理学院,广东惠州516007

出　　处：《中国沙漠》2015年第6期1473-1482,共10页Journal of Desert Research

基　　金：教育部高等学校博士点专项新教师类基金项目(20094407120004);国家自然科学基金项目(41301004);中国科学院地球环境研究所黄土与第四纪地质国家重点实验室开放基金项目(SKLLQG1013)

摘　　要：福建东部平潭岛白青乡剖面由一套白-灰黄色风成砂(简称"风成砂")和红色风成砂("老红砂")互相叠覆构成,其时代为150~20ka BP。粒度分析结果显示,剖面中的风成砂和老红砂都以砂粒级为主,次为粉砂,最少为黏土。这两者的粒度参数特征与当地现代海滩沙存在显著差别,与现代风成沙相似,但这两者均比现代风成沙具有较高含量的粉砂和黏土。这些粒度及其参数特征揭示出150~20ka BP福建东部海岸地区经历了4个暖湿亚段"W"和4个冷干亚段"C",分别为W4(133~117ka BP)、W3(108~99ka BP)、W2(84~67ka BP)、W1(50~20ka BP)和C4(150~133ka BP)、C3(117~108ka BP)、C2(99~84ka BP)和C1(67~50ka BP)。这些"W"和"C"亚段与LR04深海氧同位素、65°N夏季太阳辐射和相对海平面变化在气候波动性质和相位上相对应。150~20ka BP在万年尺度上,中国东南沿海海岸风沙沉积受到诸如太阳辐射、东亚季风和海平面波动等全球大背景因素控制。Located on the Pingtan Island of eastern Fujian Province,the Baiqingxiang section consists of greyish-white to yellow aeolian sands(hereafter, ' white aeolian sands')and red aeolian sands(hereafter, 'old red sands')that alternate to some extent with red aeolian sands with an age of 150 to 20 ka BP.Our grain-size analyses showed that both the old red sands and the white aeolian sands are mainly sand grains,with minor silt and low clay contents.Their grain-size characteristics and parameters differ greatly from those of local modern beach sands,but are similar to those of modern aeolian sands,and both the old red sands and the white aeolian sands contain more silt and clay than modern aeolian sands.The alternation in their features suggests that the eastern coast of Fujian Province has experienced four warm-humid(W)periods and four cold-dry(C)periods from150 to 20 ka BP:W4(133to 117 ka BP),W3(108to 99 ka BP),W2(84to 67 ka BP),and W1(50to20 ka BP),and C4(150 to 133 ka BP),C3(117 to 108 ka BP),C2(99 to 84 ka BP),and C1(67 to 50 ka BP).These periods correspond well to the climate fluctuations recorded in the LR04 benthic stack curves,the 65 N summer solar radiation data,and relative sea-level changes.This suggests that sand deposition on China's southeastern coast has been subject to global climate factors,such as solar radiation,the East Asian monsoons,and sea-level fluctuations,at a scale of approximately 10 ka from150 to 20 ka BP.

关 键 词：平潭岛 海岸风成砂 粒度特征 古气候 

分 类 号：P736.21[天文地球—海洋地质]