Geomorphology and Paleoclimatology of Lake Lisan Terraces, Dead Sea, Jordan

约旦死海利桑湖梯田地貌学和古气候学

• 批准号: 16113225
• 负责人: Professor Dr. Stephan Kempe
• 金额: --
• 依托单位: Institut für Angewandte Geowissenschaften (IAG)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2006
• 资助国家: 德国
• 起止时间: 2005-12-31 至 2010-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/16113225?language=en
• 关键词: Geomorphology; Paleoclimatology; Lake; Lisan; Terraces

The levels of closed lakes such as the glacial Lake Lisan/Near East (63-15 ka B.P.) (Kaufman et al.,1992) are a result of changes in evaporation and precipitation.However, in an actively subsiding basin such as the Dead Sea (today at ¿425m) tectonic activity may contribute to the lake level recession. The retreat of Lake Lisan left behind a sequence of deposits and shore terraces. The ability to determine shore line elevations and to date them offers good possibilities to evaluate hydrologic changes, paleoclimatic conditions and tectonic activity during the Last Glacial. Therefore, the main goals of this study are: 1) investigating geometrical and morphological characteristics of Lake Lisan erosional terraces, in the eastern side of the Dead Sea, such as elevation, gradient, width, length etc. and dating these terraces. This investigation should give additional water level data and rates of level retreat for Lake Lisan. Moreover, it helps to construct a model of lake-level regression, which allows to correlate the levels of the lake with paleoclimatic changes; 2) examining the distribution and thickness of the Damya Formation which overlies the Lisan Formation. The results should narrow down the timing of the late Pleistocene period of the lake level high stand and give information on the altitude of the high stand and the paleoenvironment of the subsequent period; 3)Investigating the stratigraphy, lithology and mineralogy of the Lisan Formation, and recording the vertical distribution of syn- and postdepositional sediment sliding horizons, such as slumps and seismites. This shall give indicators of the past water chemistry and of the paleoenvironment conditions of the lake. Moreover, it will provide information on the vertical displacement along E-W faults and indicate whether the retreat of Lake Lisan was affected by tectonic subsidence or not. These questions will be investigated during a field campaign in August-September 2005, when the terraces will be surveyed by GPS and samples for dating and comparative sedimentological analysis will be collected.

63-15 kaB. P.封闭湖泊的水位，如冰川形成的里三湖/近东湖（Lisan/Near East）（考夫曼等人，然而，在一个活跃的下沉盆地，如死海（今天在<$425米），构造活动可能有助于湖平面的下降。李三湖的退缩留下了一系列沉积物和海岸阶地。确定海岸线高程并测定其日期的能力为评估末次冰期水文变化、古气候条件和构造活动提供了很好的可能性。因此，本研究的主要目的是：1）调查死海东侧里三湖侵蚀阶地的几何和形态特征，如海拔、坡度、宽度、长度等，并确定这些阶地的年代。这项调查应提供更多的水位数据和水位撤退率的里三湖。此外，它有助于建立一个模型的湖泊水位回归，这使得相关的湖泊水位与古气候变化; 2）检查的分布和厚度的Damya组上覆的里三组。3）对里三组进行了地层学、岩性和矿物学研究，记录了同期和沉积后沉积物滑动层位（如滑塌和震积岩）的垂向分布。这将提供过去的水化学和湖泊的古环境条件的指标。此外，它还将提供沿沿着东西向断裂的垂直位移信息，并指示里三湖的退缩是否受到构造沉降的影响。这些问题将在2005年8月至9月的一次实地活动中进行调查，届时将用全球定位系统对梯田进行测量，并将收集样品进行年代测定和比较沉积学分析。