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Northwest African biomes and climate variability during the Pliocene

上新世期间西北非生物群落和气候变化

基本信息

批准号：
180291152
负责人：
Dr. Lydie Madeleine Dupont
金额：
--
依托单位：
Zentrum für Marine Umweltwissenschaften (MARUM)
依托单位国家：
德国
项目类别：
Infrastructure Priority Programmes
财政年份：
2010
资助国家：
德国
起止时间：
2009-12-31 至 2013-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/180291152?language=en
关键词：
Northwest African biomes climate variability

项目摘要

This project strives for a much improved understanding of the variability of climate and vegetation in Northwest Africa and its driving forces during the Pliocene. Specifically, the role of enhanced overturning circulation and northward heat transport due to closure of the Central American Seaway (CAS) in causing the Mid-Pliocene Warm Period (MPWP) with increased tropical rainfall and extension of savannah woodland and forest biomes will be investigated. Therefore, we will utilize sediments from ODP Site 659, located ideally to record aeolian-transported signals from the savannah-forest transition. Past rainfall variability will be reconstructed by D/H analyses on plant waxes with information on the expansion of C4 grasses (emergence of the modern savannah biome) from lipid 13C analyses. In conjunction, marine palynology will provide detailed information on vegetation composition enabling biome reconstructions. Existing records of dust flux and deep-ocean circulation changes will be used for comparison. The period 3.6-3.0 Ma will be investigated in millennial-scale resolution. In the 3rd year, these analyses will be extended to the interval preceding the CAS closure (4.9- 4.6 Ma) with reduced northward heat transport and without Northern Hemisphere ice sheets to detect climatic and vegetation variability without these forcing factors.

该项目致力于更好地了解西北非气候和植被的变化及其上新世期间的驱动力。具体来说，将调查由于中美洲海道（CAS）关闭而导致的上新世中期温暖期（MPWP）增强的翻转环流和向北热量输送的作用，从而导致热带降雨增加以及草原林地和森林生物群落的扩展。因此，我们将利用 ODP 站点 659 的沉积物，该站点地理位置优越，可以记录来自稀树草原-森林过渡的风沙传输信号。过去的降雨量变化将通过对植物蜡的 D/H 分析以及来自脂质 13C 分析的 C4 草的扩张（现代草原生物群落的出现）的信息来重建。同时，海洋孢粉学将提供有关植被组成的详细信息，从而实现生物群落重建。现有的尘埃通量和深海环流变化记录将用于比较。 3.6-3.0Ma时期将以千年尺度的分辨率进行研究。在第三年，这些分析将扩展到 CAS 关闭之前的时间段（4.9-4.6 Ma），向北的热量传输减少，并且没有北半球冰盖，以在没有这些强迫因素的情况下检测气候和植被变化。