Anatomy, age and origin of an intramontane top basin surface (Sorbas Basin, Betic Cordillera, SE Spain)

Stokes, M., Mather, A., Rodés, Á. , Kearsey, S. and Lewin, S. (2018) Anatomy, age and origin of an intramontane top basin surface (Sorbas Basin, Betic Cordillera, SE Spain). Quaternary, 1(2), 15. (doi: 10.3390/quat1020015)

Abstract

Collisional mountain belts commonly develop intramontane basins from mechanical and isostatic subsidence during orogenic development. These frequently display a relict top surface, evidencing a change interval from basin infilling to erosion often via capture or overspill. Such surfaces provide markers that inform on orogenic growth patterns via climate and base level interplay. Here, we describe the top surface from the Sorbas Basin, a key intramontane basin within the Betic Cordillera (SE Spain). The surface is fragmentary comprising high elevation hilltops and discontinuous ridges developed onto the variably deformed final basin infill outcrop (Gochar Formation). We reconstruct surface configuration using DEM interpolation and apply 10Be/26Al cosmonuclides to assess surface formation timing. The surface is a degraded Early Pleistocene erosional pediment developed via autogenic switching of alluvial fan streams under stable dryland climate and base level conditions. Base-level lowering since the Middle Pleistocene focused headwards incision up interfan drainages, culminating in fan head capture and fan morphological preservation within the abandoned surface. Post abandonment erosion has lowered the basin surface by 31 m (average) and removed ~5.95 km3 of fill. Regional basin comparisons reveal a phase of Early Pleistocene surface formation, marking landscape stability following the most recent Pliocene-Early Pleistocene mountain building. Post-surface erosion rate quantification is low and in accordance with 10Be denudation rates typical of the low uplift Betic Cordillera.

• Item Type: Articles
• Additional Information: This research was part funded by NERC grants CIAF 9039-1007 and NE/F00642X/1.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Rodes, Dr Angel
• Authors: Stokes, M., Mather, A., Rodés, Á., Kearsey, S., and Lewin, S.
• College/School: College of Science and Engineering > Scottish Universities Environmental Research Centre
• Journal Name: Quaternary
• Publisher: MDPI
• ISSN: 2571-550X
• ISSN (Online): 2571-550X
• Published Online: 24 August 2018
• Copyright Holders: Copyright © 2018 The Authors
• First Published: First published in Quaternary 1(2): 15
• Publisher Policy: Reproduced under a Creative Commons License