Mid to late holocene alluvial fans activity at the southern sector of sierra de gredos in central Spain: Climate literature review, OSL and topographical analysis

Muñoz-Salinas, E., Castillo, M., De Pablo, N., Palacios, D., Sanderson, D. and Cresswell, A. (2024) Mid to late holocene alluvial fans activity at the southern sector of sierra de gredos in central Spain: Climate literature review, OSL and topographical analysis. Quaternary International, 688, pp. 44-52. (doi: 10.1016/j.quaint.2024.02.007)

Abstract

Alluvial fans are rapidly evolving landforms sensitive to changes in tectonic and climatic conditions. Their study provides useful information to unravel the landscape evolution of lowlands and mountainous regions where sediment transported by rivers originates. The chronology of alluvial fan deposits is crucial for the flood risk assessment of those populations settled on this type of dynamic landform. Here we provide (1) a review of the literature concerning climatic reconstructions for the Sierra de Gredos, (2) optically stimulated luminescence (OSL) ages and (3) topographical analysis to reconstruct the recent events that built-up the alluvial fans of the southern sector of Sierra de Gredos (Central Spain). The area is tectonically active and has a relatively simple lithology given by a deformed and fractured Paleozoic granite massif that was heavily eroded by Quaternary glacial advances. Our OSL results indicate that the recent build-up events span from ca. 5 ka up to the end of the 19th century. The chronology of events is consistent with the climatic change reported for Central Spain, where humidity seems to be a primary control in the recent activity of the alluvial fans. Additionally, topographic analysis on a 5-m-resolution LIDAR DEM help us to propose that, tectonics have been a major control of Gredos alluvial fans in a long-term scale, longer than the Holocene but, since the mid-Holocene to the present, climate is a primary control on their landscape evolution. We conclude that current climatic conditions favor fan degradation for the Gredos alluvial fans rather than sediment transport and fan aggradation. The present study emphasizes the necessity of supplementing OSL chronologies with other long-term geochronological techniques to confine the constructive periods of fans for the entire Holocene.

• Item Type: Articles
• Additional Information: This research was done thanks to the UNAM grants DGAPA-PAPIIT IN101720 and DGAPA-PASPA No.523.01/0532DFA/DBE/2021 granted by the first author.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Sanderson, Professor David and Cresswell, Dr Alan
• Authors: Muñoz-Salinas, E., Castillo, M., De Pablo, N., Palacios, D., Sanderson, D., and Cresswell, A.
• College/School: College of Science and Engineering > Scottish Universities Environmental Research Centre
• Journal Name: Quaternary International
• Publisher: Elsevier
• ISSN: 1040-6182
• Published Online: 16 February 2024