机构地区:[1]自然资源部第一海洋研究所,海洋地质与成矿作用重点实验室,山东青岛266061 [2]青岛海洋科学与技术试点国家实验室,海洋地质过程与环境功能实验室,山东青岛266237 [3]南京大学,中国南海研究协同创新中心,江苏南京210093 [4]日本高知大学,海洋岩芯高级研究中心,日本高知783-8502 [5]青岛海洋科学与技术试点国家实验室,海洋同位素与地质年代测定平台,山东青岛266237
出 处:《第四纪研究》2020年第3期658-672,共15页Quaternary Sciences
基 金:国家重点基础研究发展计划项目(批准号:2016YFA0601903);青岛海洋科学与技术试点国家实验室鳌山科技创新计划项目(批准号:2016ASKJ13);中央级公益性科研院所基本科研业务费专项项目(批准号:2017S01);国家自然科学基金项目(批准号:U1606401和41722603);山东省"泰山学者"建设工程专项经费项目(批准号:TSQN20182117)共同资助。
摘 要:西北太平洋海陆相互作用强烈,受黑潮和亚洲大陆风尘输入影响显著,是研究海洋沉积物中有机碳埋藏与陆源输入、海洋初级生产力和海洋环境演化关系的理想靶区。本研究基于采自九州-帕劳海脊北部的重力活塞647 cm长的KPR12岩芯,分析了总有机碳(TOC)、总氮(TN)、有机碳稳定碳同位素组成(δ^13CTOC)、蛋白石(Opal)以及粒度等指标,初步探讨了近40万年来轨道尺度沉积有机碳的来源、埋藏特征及其影响机制。岩芯的TOC含量平均值为0.214%,呈冰期较高、间冰期较低的旋回特征。岩芯沉积物粒度的不同端元反映了研究区风尘输入大致呈冰期较高的趋势。岩芯的δ^13CTOC(-25.24‰^-21.04‰,平均值为-22.59‰)显示有机质以海源为主(约62%),海源有机碳含量趋势与TOC的变化一致。研究区不同时期陆源物质的输入受风尘输送和黑潮的综合控制,黑潮增强可能对该区间冰期陆源有机碳贡献的升高有一定影响。岩芯中TOC与Opal含量的相关性分析表明,海洋初级生产力可能不是控制该岩芯有机碳含量变化的主要原因。冰期-间冰期旋回中的深层水通风条件、黑潮和北太平洋中层水的发育以及陆源细颗粒物质输入可能共同影响着本区沉积有机碳的降解与埋藏保存。In the global carbon cycle,the burial of organic carbon(OC)in marine sediments in geological periods is closely related to terrestrial input,marine primary productivity and marine environment.There is a lack of long-term OC record in the Northwest Pacific(NWP)Ocean,where is an ideal target region for studying the source,burial and preservation of OC with its environmental implication in the glacial-interglacial cycles.In this study,based on the glacial-interglacial timescale,we present a record of sedimentary OC burial from northern Kyushu-Palau Ridge since Late Quaternary and preliminarily explain their controlling factors and the potential environmental implication.The gravity core KPR12(647 cm length)was collected from the northern Kyushu-Palau Ridge in the NWP(29°28'N,133°37'E;2590 m in depth)in 2016,where is affected by the Kuroshio Current,the dust input from Asian Continent and the volcanic eruption of Kyushu Island in Japan.We used AMS 14C dating,planktonic foraminiferal oxygen isotope records to establish the age model.We also analyzed the sediment grain size,opal,total organic carbon(TOC),total nitrogen(TN),stable carbon isotope of TOC(δ^13CTOC),and finally established the sediment record of OC burial in this area through the last 400 ka.The results showed that the mean TOC content is 0.214%,which is characterized by higher values during glacial periods compared to that in the interglacial time(OCGlacial=0.25%,OCInterglacial=0.18%).The meanδ^13CTOC value in this core is-22.59‰,indicating a mixed OM sources with the dominant contribution from marine origin(ca.62%).There existed a good correlation trend between TOC and marine-derived OC,suggesting that the variation of TOC record may co-varied with the changes of marine-derived OC;while the terrestrial OC is probably correlated to the Kuroshio Current and dust input.The variations of the end members of grain size can reflect the influence of Westerlies(F1:5.23μm,fine grain),East Asian Winter Wind(F2:19.87μm,medium-coarse grain)and volcanic materia
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