Landscape evolution in the northeastern Iranian Plateau reconstructed from Late Pleistocene to Holocene sediment archives

从晚更新世到全新世沉积档案重建的伊朗高原东北部景观演化

• 批准号: 452625374
• 负责人: Professor Dr. Roland Baumhauer
• 金额: --
• 依托单位: Arbeitsbereich Physische Geographie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/452625374?language=en
• 关键词: Landscape; evolution; northeastern; Iranian; Plateau

Very few studies on reconstructing landscape evolution inferred from Late Pleistocene and Holocene sediment archives in the Iranian highlands were conducted so far. Primarily, this is due to the limited significance of terrestrial sediments from semi-arid environments. In contrast to lake sediments, they bear poor amounts of biogenic environmental and climate proxy indicators, but anyway provide essential information for reconstructing past environmental and climatic conditions. Restrictions range from difficult access to an important archive, to extreme environmental conditions with temporally and spatially diverging morphodynamic conditions and to complications during data interpretation, which are following these archive discontinuities.However, detailed analysis of Quaternary relief features allows for a combined examination of multiple geological archives and thus enables a synthesis from conclusions about the predominating environmental conditions during their formation. This way, even geological archives with limited coverage in space and time and only sporadic appearance connect efficiently for an extensive paleo environmental reconstruction. One of the most important aspects here is the precise determination of the time of deposition, as a correlation of the diverging sediment facies is very limited otherwise. Therefore, the chronostratigraphic classification of the archives is a crucial part of the correlation and combination of their individual paleoenvironmental signals.In course of the applied project, effect and extent of the post-LGM lake level retreat within the Bajestan Playa in the northeastern Iranian Bardeskan Basin will be determined. This will provide a base for the reconstruction of regional and supraregional tendencies of late Pleistocene and Holocene environmental change. Notably at the southern border of today’s playa, a rich inventory of mostly erosional and deflational landforms has developed in course of the lake level retreat, which keeps record of the most recent landscape evolution. A prevailing relief inversion took place at the transition zone to the distally dissected alluvial fan and plain, and left an extraordinary convenient situation of outcrops. This shall now be utilised for detailed geomorphological, stratigraphical and chronostratigraphical studies, in order to reconstruct the course of the lake level retreat and the subsequent landform succession.

根据伊朗高原晚更新世和全新世沉积物档案重建景观演化的研究目前还很少。这主要是由于来自半干旱环境的陆地沉积物的意义有限。与湖泊沉积物相比，它们承担的生物环境和气候代理指标较少，但无论如何都为重建过去的环境和气候条件提供了重要的信息。限制范围从难以访问重要档案，到具有时间和空间差异的形态动力学条件的极端环境条件，以及数据解释期间的复杂性，这些都是随着这些档案的不连续性而产生的。然而，对第四纪地貌特征的详细分析可以综合考察多种地质档案，从而可以从形成时的主要环境条件的结论中得出综合结论。这样，即使是在空间和时间上覆盖有限，只有零星出现的地质档案，也能有效地连接起来，进行广泛的古环境重建。这里最重要的一个方面是精确确定沉积时间，否则，对不同沉积相的对比是非常有限的。因此，档案的年代地层分类是对其个体古环境信号进行对比和组合的重要组成部分。在申请项目的过程中，将确定伊朗Bardeskan盆地东北部Bajestan Playa内lgm后湖泊水位下降的影响和程度。这将为重建晚更新世和全新世环境变化的区域和超区域趋势提供基础。值得注意的是，在今天的playa的南部边界，在湖面退缩的过程中，形成了丰富的地貌清单，其中大部分是侵蚀和收缩地貌，记录了最近的景观演变。在向远端解剖的冲积扇和平原过渡带，发生了普遍的地形反转，为露头留下了极为有利的条件。现在将利用这些资料进行详细的地形学、地层学和年代地层学研究，以便重建湖面退缩的过程和随后的地貌演替。