Glacial erosion and paleoclimate reconstruction

冰川侵蚀与古气候重建

• 批准号: 5445120
• 负责人: Professor Dr. Joachim Kuhlemann
• 金额: --
• 依托单位: Forschungsbereich Mineralogie und Geodynamik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2005
• 资助国家: 德国
• 起止时间: 2004-12-31 至 2007-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5445120?language=en
• 关键词: Glacial; erosion; paleoclimate; reconstruction

Investigation of glacial deposits and trimlines in Corsica enabled us to map the maximum extent of glaciers during the Würmian glaciation. Glaciers reached down to elevations of 500 m a.s.l., much deeper than documented in the literature. Moreover, two generations of pre-Würmian trimlines and roches moutonnees and few deposits prove even wider extent of glaciers. The relief was obviously modified to a higher degree than previously assumed. Glaciations appear to play a key role for the destruction of Miocene paleosurfaces. Ort the other hand, high-elevated relics of Miocene paleosurfaces display a remarkable potential for selfamplifying accumulation of large ice fields. The reconstruction of the ancient equilibrium line altitude (ELA) pattern provides important information an the regional climate during the Würmian maximum glaciation in the northwestern Mediterranean. Two preWürmian maximum glacial expansions can be locally constrained, which offer an opportunity to roughly estimate ELA-lowering and paleotemperature. A reconstruction of the Würmian ELA distribution will increase in reliability if the maximum glacier extent can be linked with one of the several short periods of glacier expansion within the Würmian glacial cycle. Thus, a robust stratigraphic framework for moraine deposits needs to be established. Therefore, we aim to determine exposure ages of large boulders rising above Würmian moraines by means of dating 10Be cosmogenic nuclides. Glaciofluvial terraces shall be dated by luminescense methods. Pre-Würmian erosional landforms shall mostly be dated by 10Be cosmogenic nuclides of erosion features. In a larger geographic frame, Corsica plays a key role for the glacial climatic setting of the western Mediterranean and Europe as a whole. High pressure in central Europe during füll glacial conditions has likely blocked eastward moving cyclons and frequently pushed them into the northwestern Mediterranean realm, where the high mountains of Corsica form an obstacle to moisture transport.

对科西嘉岛冰川沉积和边界线的调查使我们能够绘制出维尔眠冰川时期冰川的最大范围。冰川向下延伸到海拔500英里，比文献中记载的要深得多。此外，两代前乌尔眠时期的剪切线和罗克穆通尼山脉和很少的沉积物证明了更广泛的冰川范围。救济显然被修改到了比之前假设的更高的程度。冰川似乎对中新世古地表的破坏起到了关键作用。另一方面，中新世古地表的高隆起遗迹对大冰原的堆积具有显著的自证作用潜力。古平衡线高度(ELA)模式的重建为研究地中海西北部维尔眠最大冰期的区域气候提供了重要信息。Prewürmian冰川的两次最大扩张可以在当地受到限制，这为粗略估计ELA下降和古温度提供了机会。如果最大冰川范围能够与维尔眠冰川周期内几个短暂的冰川扩张周期中的一个联系起来，那么重建维尔眠ELA分布将提高可靠性。因此，需要建立一个强有力的冰河沉积地层框架。因此，我们的目标是通过10Be宇宙成因核素测年的方法来确定上升于维尔眠冰川之上的大巨石的暴露年龄。冰川阶地的年代测定应采用发光法。乌尔棉期以前的侵蚀地貌主要由10Be宇宙成因核素来确定侵蚀特征。在更大的地理范围内，科西嘉岛对西地中海和整个欧洲的冰川气候背景起着关键作用。在füll冰川条件下，欧洲中部的高压很可能阻止了气旋向东移动，并经常将它们推入地中海西北部地区，在那里，科西嘉岛的高山构成了水汽输送的障碍。