1200年来湖光岩玛珥湖高分辨率元素地球化学记录  

HIGH RESOLUTION ELEMENTS GEOCHEMICAL RECORD DURING THE PAST 1200 YEARS IN HUGANGYAN MAAR LAKE

作　　者：谢曼曼[1] 孙青[1] 王宁[1] 朱庆增[2] 单雅冰 李爱国[3] 杨科[3] 毛成文[3] 王喜生[4] 储国强[2] 刘嘉麒[2] 

机构地区：[1]国家地质实验测试中心,北京100037 [2]中国科学院地质与地球物理研究所新生代地质与环境重点实验室,北京100029 [3]中国科学院上海应用物理研究所,上海201204 [4]中国地质科学院地质力学研究所,北京100081

出　　处：《第四纪研究》2015年第1期152-159,共8页Quaternary Sciences

基　　金：国家自然科学基金面上项目（批准号：41302141,41371219和41274074）和中国地质调查局地质调查项目（批准号：1212011120045）共同资助

摘　　要：本文运用同步辐射X射线荧光光谱原位微区分析方法对湖光岩玛珥湖湖泊沉积物进行了分析,以核素测年（137Cs、210Pb和AMS 14C）数据为时间标尺,获得了1200年来Ti、Fe、Cu、Zn、Rb和Br等元素含量的高分辨率数据.Br元素含量与当地气象记录降水量变化大致呈正相关,可能说明区域降水是Br元素含量变化的主要影响因素.对1200年来Br元素含量的谱分析结果表明,Br元素含量变化的准周期分别为：1.5a、1.9～2.0a、2.1～2.6a、2.9～3.0a、374～442a和221～256a.其中,年际准周期变化可能与厄尔尼诺相关,而百年尺度的变化可能与太阳活动有关.从Ti元素含量与器测数据对比来看,Ti元素含量较高的时期也对应于降水量较大的时段,降水增加可能有利于碎屑物的搬运,但植被覆盖度、粒度效应等因素对沉积物中Ti元素存在正-负反馈机制.sampling precision. Synchrotron radiation X-ray fluorescence spectroscopy （SRXRF） in-situ analysis is a new method developed in recent years, which could realize high-resolution at seasonal to yearly timescale. Huguangyan Maar Lake （21°09＇N, 110°17＇E） belongs to the Lei Qiong Volcanic Field, located twenty kilometers southwest of Zhanjiang City, Guangdong Province. It is a closed lake with a surface area of 2.3km2 and catchment of 3.5km^2. Because of its closed natural and a lack of stream inputs, it makes this site a natural weather station and an ideal candidate for paleoclimatic archives. Here, we present a high resolution paleoclimate reconstruction of the past 1200 years from a 1.0m-long sediment core in Hugangyan Maar Lake. Age control in the core is based on 137Cs, 210Pb and AMS 14C data. Radiocarbon dating was done by accelerator mass spectrometry on leaves picked in 53cm and 94cm of the core from Hugangyan. Two 14C ages were calibrated to calendar years, 1212A.D. and 815A.D., using the atmospheric decadal data set from the calibration program CALIB 4.3. Elements concentration have been analyzed by using a method of synchrotron radiation X-ray fluorescence （SRXRF）. It provides a powerful analytical technique to detect most chemical elements of the periodic table down to limits of a few ppm. In this study, the fitted peak areas of elements Ti, Fe and Rb were normalized by the region of interest from 1946 to 1974 channels, while the fitted peak areas of elements Cu, Zn and Br were normalized by peak area of Compton scattering fitted. The Chinese national standard material GBW 07301a was used to control the analysis quality. The elements concentration in lake sediments have been regulated by many factors such as physical and chemical process, particle size, vegetation and so on. Bromine is a typical biogenic element, and is essential for growth of plants, bacteria and plankton. In lake sediments, bromine comes mainly from biogenic matter in soil and plankton in the lake. In order to unders

关 键 词：同步辐射X射线荧光光谱原位微区分析 湖光岩玛珥湖 高分辨率 古气候 

分 类 号：P575.5[天文地球—矿物学] P941.78[天文地球—地质学]