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Jungquartäre Hangsedimente als Archive der Landschaftsgeschichte in der Colorado Front Range, U.S.A.

作为美国科罗拉多前岭景观历史档案的年轻第四纪斜坡沉积物

基本信息

批准号：
190161295
负责人：
Professor Dr. Jörg Völkel
金额：
--
依托单位：
School of Agriculture and Environment
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2011
资助国家：
德国
起止时间：
2010-12-31 至 2014-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/190161295?language=en
关键词：
Jungquart re Hangsedimente als Archive

项目摘要

The subalpine to montane zones of the Colorado Front Range, U.S.A. are characterized by the abundance of stratified slope deposits exhibiting depths > 1 m and recurring sediment characteristics within the respective strata complexes. Apart from the initial description by Leopold et al. (2008a), they have not been investigated up to now in terms of either their genesis or age. First OSL dating attempts demonstrate the general applicability of the dating method in this context and render last glacial ages ranging between 40 and 12 ka. Across a landscape transect stretching W-E from the subalpine zone east of the Continental Divide (tree line at Niwot Ridge) to the zone of the Foot Hills at the border with the Great Plains (Boulder), 20 representative profiles are investigated with regards to hypsometric differences in stratification, sediment characteristics and morphodynamics. Most notably the montane zone of the Colorado Front Range is characterized by a lack of paleoclimatically interpretable geoarchives due to its semiarid climatic conditions. Additionally the slope sediments provide a basis for discussing the position of the permafrost line during the LGM. Therefore the project contributes a novel approach to the reconstruction of paleoenvironments and paleoclimates across the various altitudinal zones of the Colorado Front Range.

美国科罗拉多州前岭的亚高山到山地地区的特点是存在丰富的层状斜坡沉积物，其深度 > 1 m，并且在各自的地层复合体内具有重复出现的沉积物特征。除了利奥波德等人的最初描述。 (2008a)，到目前为止，还没有对它们的起源或年龄进行调查。第一次 OSL 测年尝试证明了该测年方法在这种情况下的普遍适用性，并得出末次冰河时代的范围在 40 到 12 ka 之间。从大陆分水岭以东的亚高山地区（尼沃特山脊的林木线）到大平原（博尔德）边界的山麓地区，横跨东西向延伸的景观横断面，对 20 个代表性剖面的分层、沉积物特征和形态动力学方面的海拔差异进行了研究。最值得注意的是，科罗拉多前岭的山地地区由于其半干旱的气候条件，缺乏古气候可解释的地质档案。此外，斜坡沉积物为讨论末次盛冰期期间永久冻土线的位置提供了基础。因此，该项目为重建科罗拉多州前沿山脉各个海拔区域的古环境和古气候提供了一种新颖的方法。