Late Pleistocene desiccation of Lake Tana, source of the Blue Nile.

更新世晚期，青尼罗河源头塔纳湖干涸。

• 批准号: NE/D012996/1
• 负责人: Henry Lamb
• 金额: $ 43.53万
• 依托单位: Aberystwyth University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2006
• 资助国家: 英国
• 起止时间: 2006 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FD012996%2F1
• 关键词: Late; Pleistocene; desiccation; Lake; Tana

Lake Tana, in the highlands of northern Ethiopia, is the source of the Blue Nile, one of the world's great rivers. Surprisingly, very little is known about the age and history of this lake: one estimate from the 1930's is that it was formed 10,000 years ago by a lava dam. Similarly, little is known about the climatic history of the wider region that comprises the Blue Nile headwaters, despite the fact that the Nile has long been recognized as critical to the resources of ancient and modern Egypt. New geophysical and core data, obtained by us in October 2003 and September 2004 with NERC support, show that the lake may be at least 40,000 years old. Our new data also show that the lake dried out at around 16,000 years ago, and almost certainly at apparently regular intervals during the later stages of the last Ice Age. It is possible that the lake dried because of intense droughts lasting one or two hundred years, and that the droughts were caused by disruption of Africa's monsoon climate when iceberg-laden meltwater from North America flooded the North Atlantic - the Heinrich events. In this new PalaeoTana Project, we aim to test these hypotheses by drilling a sediment core, up to 100m in length, from the northern basin of Lake Tana, in about 10m water depth, and about 2km from shore. The core will be scanned at high resolution using X-ray fluorescence, X-ray and colour imagery, geophysical and magnetic core-scanning technology, without damaging the sedimentary components. The resulting datasets will identify past desiccation events, which will be investigated in detail and interpreted by comparison to sediments of the known drying-out event at 16,000 years ago. Dating the sediments by appropriate methods including luminescence, tephrochronology, and Argon-Argon dating will allow precise estimates of the timing and duration of the drought events. The relative timing of these events in comparison with abrupt climatic events in ocean cores (especially Heinrich events), and in other continental records, will allow inferences about the global- scale mechanisms of abrupt climate change. The data can also be used to test climate models, and thus to help judge the accuracy of model-predicted abrupt climate change in the future. A long core record of past climate and environment from this part of Africa would have major significance for understanding both regional environmental change, because of the influence of the Nile on NE Africa and the eastern Mediterranean, and global climate. It will contribute to understanding how future changes in ocean temperature and circulation will affect global climate, especially in the heavily populated monsoon regions of Africa and Asia. It will also have significance for understanding the later stages of human evolution in and dispersal out of Africa, by providing a record of the environmental changes that influenced early human populations and their water, plant and hunting resources.

塔纳湖位于埃塞俄比亚北部高地，是世界大河之一青尼罗河的源头。令人惊讶的是，人们对这个湖的年龄和历史知之甚少：20世纪30年代的一项估计是，它是在1万年前由熔岩坝形成的。同样地，尽管人们一直认为尼罗河对古代和现代埃及的资源至关重要，但人们对包括青尼罗河源头在内的更广泛地区的气候历史知之甚少。2003年10月和2004年9月，我们在NERC的支持下获得了新的地球物理和岩心数据，表明该湖可能至少有4万年的历史。我们的新数据还显示，该湖在大约1.6万年前干涸，几乎可以肯定，在最后一个冰河时代的后期，湖泊会以明显规律的间隔干涸。有可能湖泊干涸是因为持续了一到两百年的严重干旱，而干旱是由于来自北美的满载冰山的融水涌入北大西洋，破坏了非洲的季风气候——海因里希事件——造成的。在这个新的古塔纳项目中，我们的目标是通过钻探一个长达100米的沉积物岩心来测试这些假设，该岩心来自塔纳湖北部盆地，水深约10米，距离海岸约2公里。将使用x射线荧光、x射线和彩色成像、地球物理和磁性岩心扫描技术对岩心进行高分辨率扫描，而不会破坏沉积成分。由此产生的数据集将确定过去的干旱事件，这些事件将被详细调查，并通过与1.6万年前已知的干旱事件的沉积物进行比较来解释。通过适当的方法测定沉积物的年代，包括发光、温度年代学和氩-氩定年法，可以精确估计干旱事件的时间和持续时间。将这些事件的相对时间与海洋核（特别是海因里希事件）和其他大陆记录中的气候突变事件进行比较，将有助于推断气候突变的全球尺度机制。这些数据还可以用来测试气候模型，从而帮助判断模型预测未来气候突变的准确性。非洲这一地区过去气候和环境的长期核心记录对于理解区域环境变化（因为尼罗河对非洲东北部和地中海东部的影响）和全球气候都具有重要意义。它将有助于了解未来海洋温度和环流的变化将如何影响全球气候，特别是在人口稠密的非洲和亚洲季风区。它还将通过提供影响早期人类种群及其水、植物和狩猎资源的环境变化的记录，对了解人类在非洲进化和走出非洲的后期阶段具有重要意义。

项目成果

Reanalysis of the Atmospheric Radiocarbon Calibration Record from Lake Suigetsu, Japan

• DOI: 10.1017/rdc.2020.18
• 发表时间: 2020-03
• 期刊: Radiocarbon
• 影响因子: 8.3
• 作者: C. Bronk Ramsey;T. Heaton;G. Schlolaut;R. Staff;C. Bryant;A. Brauer;H. Lamb;M. Marshall;T. Nakagawa

The Hominin Sites and Paleolakes Drilling Project

古人类遗址和古湖钻探项目

• DOI: 10.4207/pa.2017.art104
• 发表时间: 2017
• 期刊: Paleoanthropology
• 作者: Christopher Campisano

Advanced Hyperspectral Analysis of Sediment Core Samples from the Chew Bahir Basin, Ethiopian Rift, in the Spectral Range from 0.25 to 17 µm: Support for Climate Proxy Interpretation

对埃塞俄比亚裂谷 Chew Bahir 盆地沉积物核心样本进行高级高光谱分析，光谱范围为 0.25 至 17 µm：支持气候代理解释

• DOI: 10.3389/feart.2021.606588
• 发表时间: 2021
• 期刊: Frontiers in Earth Science
• 影响因子: 2.9
• 作者: Arnold G

John Birks: Pioneer in quantitative palaeoecology

约翰·伯克斯：定量古生态学的先驱

• DOI: 10.1177/0959683614556390
• 发表时间: 2014
• 期刊: The Holocene
• 作者: Battarbee R

Reconstructing the Environmental Context of Human Origins in Eastern Africa Through Scientific Drilling

通过科学钻探重建东非人类起源的环境背景

• DOI: 10.1146/annurev-earth-031920-081947
• 发表时间: 2022
• 期刊: Annual Review of Earth and Planetary Sciences
• 影响因子: 14.9
• 作者: Cohen, Andrew S.;Campisano, Christopher J.;Arrowsmith, J. Ramón;Asrat, Asfawossen;Beck, Catherine C.;Behrensmeyer, Anna K.;Deino, Alan L.;Feibel, Craig S.;Foerster, Verena;Kingston, John D.
• 通讯作者: Kingston, John D.