晚全新世东海泥质区物源输入、源区植被变化及其影响因素：来自MD06-3039A孔的正构烷烃记录  

CHANGES OF PROVENANCE INPUT AND SOURCE VEGETATION CHANGES AND THEIR IMPACT FACTORS SINCE LATE HOLOCENE BASED ON N-ALKANES RECORDS FROM CORE MD06-3039A IN THE MUDDY AREA OF THE EAST CHINA SEA

作　　者：郑邦 周斌[1] 王可 庞洋 陈明德[3] 郑洪波 Zheng Bang;Zhou Bin;Wang Ke;Pang Yang;Chert Min-te;Zheng Hongbo(Key Laboratory of Earth Surface Geochemistry,Ministry of Education;School of Earth Sciences and Engineering,Nanjing University,Nanjing 210046,Jiangsu;2.Department of Earth and Planetary Science,Graduate school of Science,The University of Tokyo,Tokyo 113-8654;3.School of Marine Science and Resources,Taiwan Ocean University,Jilong 20224,Taiwan;4.Research Center for Earth System Science,Yunnan University,Kunming 650504,Yunnan)

机构地区：[1]南京大学地球科学与工程学院,教育部表生地球化学重点实验室,江苏南京210046 [2]东京大学地球与行星科学学院,东京113-8654 [3]台湾海洋大学海洋科学与资源学院,台湾基隆20224 [4]云南大学地球系统科学研究中心,云南昆明650504

出　　处：《第四纪研究》2018年第5期1293-1303,共11页Quaternary Sciences

基　　金：国家重大科学研究计划全球变化研究项目（批准号：2015CB953804）、青岛海洋科学与技术国家实验室开放基金资助项目（批准号：MGQNLM-KF201704）和江苏省基础研究计划自然科学基金面上项目（批准号：BK20171340）共同资助

摘　　要：东海泥质区具有稳定的连续沉积，为开展气候环境演变提供了良好的研究载体，但前人主要侧重于沉积模式、季风、洋流及海洋环境研究，关于有机碎屑输入、源区植被变化及其影响因素等方面的研究还较缺乏。本研究通过晚全新世以来东海泥质沉积序列MD06-3039A的正构烷烃等有机地球化学指标分析，发现该区域4400 cal.a B.P.以来沉积有机质具有明显的陆源高等植物输入特征，其中在3200~1300 cal.a B.P.陆源输入相对减少，被认为与该区域夏季风减弱有关。nC31/nC27正构烷烃的变化表明，物源区植被呈现3个阶段的波动，早、晚阶段草本植物相对增多，中阶段3200~1300 cal.a B.P.木本植物相对较多；与此同时，植被变化呈现次一级的波动，如隋唐大暖期草本增多，明清小冰期早期木本增多。研究认为，这个区域的草/木本植物变化对气候冷暖变化的响应可能更明显。1300 cal.a B.P.以来气候总体上继续呈凉干状态，但草本植物大量增多，这与前阶段气候变冷呈现的木本植物相对增多不同，暗示人类活动土地利用方式的改变导致植被类型发生了变化。Continuous and relatively stable mud sediment depositions in the continental shelves of the East China Sea （ECS） provide high-quality archives for better understanding terrestrial climatic and environmental changes in the Holocene. However, few studies have focused on climatic and environmental reconstructions by the use of shelf sediments, in particular, to disentangle the complex interactions of the Asian monsoons, ocean currents, organic material inputs, and vegetation changes from the drainage areas of the Yangtze River into the ECS. In this study, organic geochemical indices of n-alkanes distribution patterns, and n-alkanes indices such as the ratio of long chain alkanes and medium-short chain alkanes （LCA/MSCA）, Average Carbon Length （ACL）, Odd-even predominance （OEP）, and nC31/nC27 from an ECS core MD06-3039A are presented. The core MD06-3039A （27°43.36＇N,121°46.88＇E; water depth of 47 m） was located at the mud belt off the Zhejiang-Fujian coast on the inner shelf of ECS, and drilled by a giant gravity corer during the IMAGES MD155-Marco Polo cruise Ⅱ by R/V Marion Dufresne in 2006. The total length of the core is 8.11 m, representing sediments deposited during the past 4400 years as indicated AMS14C dating. The averaged sedimentation rate of the core is 1.7 mm/a. The sediments are mainly composed of gray to gray yellowish silty silt with some small shellfish fragments and foraminifera shells visible in different depths. We have sampled 91 samples for this study and presented records here with an average resolution of approximately 50 years. Based on our analysis, the inputs of organic matter associated with terrestrial higher plants into the studied site have been decreased during a stage of 3200~1300 cal.a B.P., reflecting most likely the decreased summer precipitation in this region. In addition, the n-alkanes distributions indicate that the input of terrestrial organic matter is Yangtze River basin dominant. Furthermore, the indices of the n-alkanes suggest that the drainage

关 键 词：有机地球化学记录 草本/木本 浙闽泥质沉积 古气候环境 人类活动 

分 类 号：P593[天文地球—地球化学] P722.6[天文地球—地质学]