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Variability of the Mediterranean Outflow on glacial-interglacial and millennial time scales

地中海流出量在冰期-间冰期和千年时间尺度上的变化

基本信息

批准号：
50643226
负责人：
Professor Dr. Martin Frank
金额：
--
依托单位：
GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2007
资助国家：
德国
起止时间：
2006-12-31 至 2012-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/50643226?language=en
关键词：
Variability Mediterranean Outflow glacial interglacial

项目摘要

Mediterranean Outflow Water (MOW) has exerted significant influence on the Late Pleistocene paleoceanography and climate evolution in the North Atlantic region through its contribution to the mid-depth Atlantic salinity budget. The MOW has been strongly influenced by changes in sea level due to the shallow (286 m) sill depth of the Strait of Gibraltar but also by changes in the hydrology of the Mediterranean Sea and the tropical Atlantic gyre. In this study we propose to reconstruct in detail the flow path, flow strength and past mixing of MOW with other eastern North Atlantic water masses through radiogenic isotope analyses of neodymium (Nd) and lead (Pb), which have the potential to unravel the evolution of MOW at unprecedented detail and precision. We will extract the dissolved radiogenic isotope signatures of bottom waters from authigenic ferromanganese coatings of bulk sediments. The isotope composition of the clay fraction will provide independent constraints on the past flow paths of the water masses. The study will be carried out on a suite of well-dated cores of hemipelagic sediments from the Portuguese margin, the Gulf of Cadiz, and from the Alboran Sea in the Western Mediterranean, which will allow the reconstruction of MOW dynamics in the eastern Atlantic Ocean back to approximately 30 ka. A lot of recent evidence points to a critical role of MOW for oceanographic changes during the last major climatic transition (Termination 1), which is why particular emphasis will be on a high resolution record of MOW variability during this period of time.

地中海流出水（MOW）通过对大西洋中深盐度收支的贡献，对北大西洋地区晚更新世古海洋学和气候演化产生了重要影响。MOW受到直布罗陀海峡浅（286米）水深造成的海平面变化的强烈影响，也受到地中海和热带大西洋环流水文变化的强烈影响。在这项研究中，我们建议通过钕（Nd）和铅（Pb）的放射性成因同位素分析，详细重建MOW的流动路径、流动强度和过去与其他北大西洋东部水团的混合，这有可能以前所未有的细节和精度揭示MOW的演变。我们将从大块沉积物的自生锰铁涂层中提取底水溶解放射性成因同位素特征。粘土组分的同位素组成将为水团过去的流动路径提供独立的约束。这项研究将在葡萄牙边缘、加的斯湾和西地中海的阿尔博兰海的一套年代确定的半深海沉积物岩心上进行，这将使东大西洋的MOW动力学得以重建，恢复到大约30年前。最近的许多证据表明，在最后一次主要气候转变（终止1）期间，MOW对海洋变化起着关键作用，这就是为什么将特别强调在这段时间内MOW变率的高分辨率记录。