Magnetostratigraphy of Pleistocene Sediments from the Republic of Georgia - Dating and Correlation of Climate Signals

格鲁吉亚共和国更新世沉积物的磁性地层学 - 气候信号的年代测定和相关性

• 批准号: 245125135
• 负责人: Professor Dr. Valerian Bachtadse
• 金额: --
• 依托单位: Sektion Geophysik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2013
• 资助国家: 德国
• 起止时间: 2012-12-31 至 2017-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/245125135?language=en
• 关键词: Magnetostratigraphy; Pleistocene; Sediments; Republic; Georgia

The discovery of hominin remains of as many as six individuals, approx. 1.8 Ma in age, in Dmanisi, Southern Georgia, marks the first appearance of human occupation in Eurasia, significantly earlier than previously thought and thus changed our understanding of the causes of the first wave of emigration out of Africa substantially. Recent studies have shown, that the only African elements in the Dmanisi site are the remains of Homo Georgicus itself and associated tools. Unambiguous European affinities of the Dmanisi fauna do not support the idea, that the early hominins followed the migration patterns of large herbivores to ensure their food supply. The details of the Dmanisi hominins furthermore suggest, that local or global changes in climate are the key driving factor for early humans to venture towards Europe, because other hypothesis are disproved. In the early Pleistocene, rapid changes of warm/cold periods are documented based on global oxygen isotope records. It has been proposed, that during one of the warm periods the onset of desertification in eastern Africa forced early hominins to migrate into Europe. It is debated, however, whether the human remains in Georgia demonstrate favorable climatic conditions for early hominins and prove a long term occupation of this area, or the Caucasus represents a stepping stone along a migration path into Eurasia. For investigation of local climatic conditions, high resolution palynology is an ideal technique to map the paleoenvironmental conditions and local responses to global climate. For such studies, however, very precise age control isinevitable.High resolution magnetostratigraphy has been shown to be a very precise correlation and dating tool especially concerning young sediments. Thus, magnetostratigraphy provides the basis for successful studies of short term variations of the paleoenvironment.In Western Georgia there are a number of sedimentary sections with proposed deposition ages from ~3 million years up to the present. This time span includes the hominid bearing deposits at Dmanisi as well as lake sediments from Armenia studied earlier (Ba1210/14-1). What makes the Georgian shallow marine sections special, however, is the extremely large amounts of pollen which can give a high resolution picture of the paleoenvironmental conditions during times of human migration through the Caucasus. Correlating the magnetostratigraphic data from Georgia with those from Armenia will allow us to compare the climatic situation in Western Georgia and Armenia during the Pleistocene.It is therefore planned to study two large sections in Guria which cover a sufficiently long time span to include the 1.8 Ma time mark (age of the Dmanisi hominins) and the southern Armenian sections. The results of this study will contribute to a precise reconstruction of the paleoclimate and paleoenvironment of the Caucasus during a crucial phase of hominin occupation in the area.

人类的发现仍然多达六个人，约为。 1.8 MA年龄在乔治亚州南部的Dmanisi，标志着欧亚大陆人类占领的首次出现，比以前想象的要早得多，因此改变了我们对第一波移民从非洲出发的原因的理解。最近的研究表明，Dmanisi站点中唯一的非洲元素是Georgicus本身和相关工具的遗迹。 Dmanisi Fauna的明确欧洲亲和力不支持这一想法，即早期的人类遵循大型草食动物的迁移方式，以确保其粮食供应。 Dmanisi人类素的细节此外，气候的局部或全球变化是早期人类冒险朝欧洲冒险的关键驱动因素，因为其他假设被驳回。在更新世的早期，根据全球氧同位素记录记录了温暖/寒冷时期的快速变化。有人提出，在一个温暖的时期，东非的荒漠化开始迫使早期的人类迁移到欧洲。然而，辩论的是，佐治亚州的人类是否表现出早期人类素的有利气候条件，并证明了对该地区的长期占领，还是高加索地区代表沿着进入欧亚大陆的迁移路径的垫脚石。为了调查当地气候条件，高分辨率的骑术是绘制古环境条件和局部对全球气候的局部反应的理想技术。然而，对于此类研究，非常精确的年龄控制是可以的。高分辨率磁层学已被证明是非常精确的相关性和约会工具，尤其是与年轻沉积物有关。因此，磁层学为成功研究古环境的短期变化提供了基础。在佐治亚州西部，有许多沉积区，拟议的沉积年龄从约300万年到现在。这个时间范围包括Dmanisi的人类轴承沉积以及早期研究的亚美尼亚湖沉积物（BA1210/14-1）。然而，使乔治亚浅海陆地与众不同的是大量的花粉，可以在人类通过高加索的人类迁移时期对古环境条件的高分辨率图片。因此，将佐治亚州的磁层学数据与亚美尼亚的磁层数据相关时间标记（Dmanisi Hominins的年龄）和亚美尼亚南部部分。这项研究的结果将有助于在该地区至关重要的人类占领阶段中对高加索的古气候和古环境的精确重建。