ABSTRACT

Till macrofabric and grain-size analysis of glacial diamictons and landforms present in several valleys of the Serra da Estrela Mountains in central Portugal were used to interpret till types and to reconstruct the glacial paleoprocess history of this mountainous region. Supraglacial melt-out and flow tills are dominant in this range. Supraglacial melt-out tills, representative of periods of glacial stability and stagnation followed by recession, present weaker fabric data and coarser, poorly sorted sediments. Flow tills, mainly representative of glacial stability followed by recession, present crude layering, and soft-sediment deformation structures with moderate fabric data and coarser to fine, poorly sorted sediments. Glacial diamictons affected by post-glacial paraglacial activity in the form of landslides were also observed in three valleys. These present weaker to moderate fabric data and coarser, poorly sorted sediments. These glacial diamictons and landforms are of particular importance in the reconstruction of the glacial dynamics and history of the Serra da Estrela Mountains due to a scarcity of chronological data based on absolute dating methods. These mountains also represent the southernmost Atlantic range in Europe where significant glaciation took place, which makes it an interesting area to investigate mountain glacial dynamics in low elevation humid Atlantic coastal ranges and compare it with other Atlantic ranges.

摘要

对存在于葡萄牙中部 Serra da Estrela 山脉的几个山谷中的冰川和地貌进行的 Till 宏观结构和粒度分析用于解释冰碛类型并重建该山区的冰川古过程历史。在这个范围内，冰上融化和流水占主导地位。冰上融化的冰层代表了冰川稳定和停滞随后衰退的时期，呈现出较弱的结构数据和更粗糙、分选不佳的沉积物。流砣主要代表冰川稳定后衰退，呈现粗糙分层和软沉积物变形结构，结构数据适中，沉积物由粗到细、分选差。在三个山谷中也观察到了以滑坡形式受到冰川后冰川活动影响的冰川二元。这些呈现较弱到中等的织物数据和较粗、分类不良的沉积物。由于缺乏基于绝对测年法的年代学数据，这些冰川地貌和地貌对于重建埃斯特雷拉山脉的冰川动力学和历史具有特别重要的意义。这些山脉也代表了欧洲最南端的大西洋山脉，那里发生了显着的冰川作用，这使得研究低海拔潮湿大西洋沿海山脉的山地冰川动力学并将其与其他大西洋山脉进行比较成为一个有趣的领域。由于缺乏基于绝对测年法的年代学数据，这些冰川地貌和地貌对于重建埃斯特雷拉山脉的冰川动力学和历史具有特别重要的意义。这些山脉也代表了欧洲最南端的大西洋山脉，那里发生了显着的冰川作用，这使得研究低海拔潮湿大西洋沿海山脉的山地冰川动力学并将其与其他大西洋山脉进行比较成为一个有趣的领域。由于缺乏基于绝对测年法的年代学数据，这些冰川地貌和地貌对于重建埃斯特雷拉山脉的冰川动力学和历史具有特别重要的意义。这些山脉也代表了欧洲最南端的大西洋山脉，那里发生了显着的冰川作用，这使得研究低海拔潮湿大西洋沿海山脉的山地冰川动力学并将其与其他大西洋山脉进行比较成为一个有趣的领域。