The influence of surface and tectonic processes on landscape evolution of the Iberian Chain (Spain): Quantitative geomorphological analysis and geochronology

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• 作者：V.N. Scotti ; P. Molin ; C. Faccenna ; M. Soligo ; A. Casas-Sainz
• 关键词：Landscape evolution ; Iberian Chain ; Uplift ; Topography ; Hydrography ; Incision rate
• 刊名：Geomorphology
• 出版年：1 February, 2014
• 年：2014
• 卷：206
• 期：Complete
• 页码：37-57
• 全文大小：4636 K

文摘

In tectonically active areas, the landscape response to tectonic forcing is described and possibly quantified by regional topographic and hydrographic features as well as by spatial variation in rates of surface processes. We investigated the recent landscape evolution of the Iberian Chain (NE Spain), an intraplate thrust-belt formed in Cenozoic times and characterized by a dome-shaped topography. In its central sector the landscape is dominated by low relief surfaces, Late Neogene (?) in age, presently standing at an average altitude of 1300 m. A recent regional uplift controlled the organization of the present fluvial network and dissection of the landscape. In this framework we investigated the geomorphic responses to tectonic forcing by the calculation of morphometric parameters, focusing on topography (map of local relief, swath profiles) and hydrography (basin hypsometric curve and integral, basin asymmetry factor, river longitudinal profiles and relative indices), and using SRTM DEM. The results of morphometric analysis have been coupled with radiometric uranium-series dating of calcareous tufas lying on fluvial strath terraces. The obtained ages allow the estimation of incision rate along the High Tajo and Mart铆n rivers. Our results indicate that uplift and rock-type erodibility are the main factors influencing landscape evolution of the study area. The incision rates are very similar throughout the central sector of the range, indicating that, despite subtle local variation, the rivers are responding to a main tectonic input: the regional uplift. In conclusion, the Iberian Chain landscape is in a transient state in response to a recent dome-like uplift. Indeed, the fluvial processes that weakly incised this landscape at a rate of ~ 0.6 mm/yr are approaching a radial pattern. On the basis of geological and geomorphic constraints, we hypothesize that the uplift started around or after 3 Ma.