江汉平原东北缘麻城剖面磁化率特征及气候环境意义  

Sediment Magnetism Characteristics and Its Climatic Environment Significance of Northeast Margin of Jianghan Plain

作　　者：张玉芬[1] 李长安[2,3] 孙习林[3] 毛欣[3] 高孟秋[3] 熊德强[1] 王金鑫[1] 

机构地区：[1]中国地质大学地球物理与空间信息学院,湖北武汉430074 [2]中国地质大学生物地质与环境地质国家重点实验室,湖北武汉430074 [3]中国地质大学地球科学学院,湖北武汉430074

出　　处：《地球科学（中国地质大学学报）》2016年第7期1225-1230,共6页Earth Science-Journal of China University of Geosciences

基　　金：国家自然科学基金项目(No.41440002);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(No.SKLLQG0908);中国地质调查局项目(No.1212011121142)

摘　　要：为了探讨和揭示江汉平原晚更新世以来沉积物磁学特征和该区的气候环境演变规律,对新近发现的位于江汉平原东北缘的麻城剖面进行了磁化率样品的采集和测试与对应年代学分析,结果表明：（1）麻城剖面沉积物质量磁化率值偏低,平均值为10.85×10-8 m3·kg-1,全剖面变化不大,为5.76×10-8~23.39×10-8 m3·kg-1,但频率磁化率波动较大,分布于5.35%~50.35%,平均值为24.71%,显示具有较高的超顺磁性颗粒（super paramagnetism,SP）含量;（2）根据磁化率和频率磁化率曲线的旋回波动特点,结合年代学测试结果,将该区的古气候环境划分为7个不同的演化阶段.初步认为该区晚更新世以来沉积环境经历了由湖沼相沉积-湖相沉积-泛滥平原中的沼泽沉积环境的变化.气候经历了温湿-干冷-暖湿-干凉-干冷-温湿-干（旱）偏冷的阶段性变化过程,与晚更新世晚期以来全球气候变化特点具有较好的一致性.In order to reveal the sediment magnetism characteristics and its climatic environment evolution since Late Pleistocene of the Jianghan plain,we collected magnetic susceptibility samples from Macheng,the northeast margin of the Jianghan plain,for analysis.The results show that the mass susceptibility of magnetic materials in Macheng profile is relatively low（10.85×10-8 m3·kg-1 on average）,and the variation range of mass susceptibility is narrow（5.76×10-8-23.39×10-8 m3·kg-1）.However,the variation range of frequency susceptibility is relatively wide（5.35%-50.35% and 24.71% on average）,which shows that the content of SP（super paramagnetism）particulate is high.The cyclic wave characteristics of magnetic susceptibility and frequency magnetic susceptibility data suggest that the paleoclimate environment of this region could be divided into 7evolution phases.According to the chronological data,it is concluded that the sedimentary environment of this region has undergone limnetic facies sedimentary stage,lacustrine sedimentary stage,swamp sedimentary stage in flood plain since Late Pleistocene,whereas the climate has undergone the phased variation of humid-dry-cold-warm-wet-dry-cool-dry-coldhumid-dry（drought）and cool,which is consistent with the global climate change characteristics since Late Pleistocene.

关 键 词：麻城剖面 磁化率 气候变化 沉积物 

分 类 号：P631[天文地球—地质矿产勘探]