Red Sea deep-water ventilation and climate variability during the past 200,000 years (REVENT)

红海是一个内陆盆地，与非洲东北部和阿拉伯半岛的半干旱到干旱地区接壤。与印度洋的水团交换仅限于狭窄而浅的曼达布海峡，该盆地接受来自边界地区的主要尘埃输入。因此，红海的海洋学和沉积过程甚至会对微妙的气候和海平面变化做出反应。在拟议的项目中，我们想要调查红海翻转环流和氧气最小区(OMZ)如何响应过去20万年来轨道和千年尺度的气候变化，以及海洋学响应是否与边界地区的水文变化和尘埃通量同步。具体地说，我们要处理这样的假设：1)红海深水通风与全球海平面有关，并受到地中海和季风气候制度的影响，2)千年尺度的气候变化，如寒冷和极度干旱事件，引起边界地区深水环流和水文的同期变化；3)尘埃通量监测非洲热带雨带的时间超越性变化，反映植被阈值和尘埃颗粒暴露。深海红海的沉积物档案似乎适合于检验这些假设，因为该盆地在大约12.5°-30°N之间延伸到SSE-NNW，因此受到高纬和低纬气候制度的影响。我们将沿着N-S断面调查三个沉积岩芯。利用红海各地的海底有孔虫稳定同位素和孔隙密度记录，对比和重建盆地范围和局部深水通风和OMZ强度的变化。来自同一档案馆的地球化学记录将用于重建陆地上的水文变化，特别是尘埃颗粒的暴露和排放，以及红海的生物地球化学过程。通过比较这些替代记录，将能够评估潮湿和干旱时期以及海洋反应的区域对比和时间超越性。这一信息也与确定和描述解剖学上的现代人跨越北非和阿拉伯半岛迁徙到地中海区域和亚洲的潜在时间窗口有关。

The Red Sea is a landlocked basin, bordered by the semiarid to arid regions of northeastern Africa and the Arabian Peninsula. The exchange of water masses with the Indian Ocean is restricted to the narrow and shallow strait of Bab al-Mandab and the basin receives major dust input from the borderlands. Consequently, the oceanography and sedimentation processes of the Red Sea respond to even subtle climate and sea-level changes. In the proposed project we want to investigate how the Red Sea overturning circulation and oxygen minimum zone (OMZ) responded to orbital and millennial-scale climate changes during the past 200,000 years and if the oceanographic responses were in phase with hydrological changes and dust fluxes of the borderlands. Specifically, we want to address the hypotheses that 1) the Red Sea deep-water ventilation is linked to global sea-level and is regionally modulated by the influence of the Mediterranean and monsoon climate regimes, 2) millennial-scale climate changes, such as cold and hyper-arid events provoke contemporaneous changes in deep-water circulation and hydrology on the borderlands, 3) the dust fluxes monitor time-transgressive shifts of the African tropical rain belt reflecting thresholds in vegetation and the exposure of dust particles. The sediment archive of the deep Red Sea appears suitable to test these hypotheses since the basin extends SSE-NNW between approximately 12.5° and 30°N and thus is influenced by high- and low-latitude climate regimes. We will investigate three sediment cores along a N-S transect. Benthic foraminiferal stable isotope and pore density records from various parts of the Red Sea will be used for correlation and reconstruction of basin-wide and local changes in deep-water ventilation and OMZ strength. Geochemical records from the same archives will be used to reconstruct the hydrological changes on land, particularly the exposure and deflation of dust particles, but also biogeochemical processes in the Red Sea. The comparison of these proxy records will allow for the evaluation of regional contrasts and time-transgressive nature of humid and dry periods and oceanographic responses. This information is also relevant for the identification and characterization of potential time windows for the migration of anatomically modern humans across North Africa and the Arabian Peninsula into the Mediterranean region and Asia.