168693 20260218132340.0 doi 10.3166/ga.24.107-122 sideral 98880 ART-2011-98880 eng Lafuente, Paloma Morphotectonics of the Concud Fault (Iberian Chain, Spain): Comparing Geomorphic and Geologic Indices of Activity of an Intraplate Extensional Fault 2011 Access copy available to the general public Unrestricted The results of geomorphic analysis of the Concud fault-generated mountain front (central Iberian Chain, Spain) are introduced into classifications of fault activity proposed by previous authors, and compared with slip rates calculated from geologic markers. The Concud fault is an extensional structure active since the mid Pliocene times. It gives rise to a 60 to 120 m high mountain front, where footwall rocks belonging to the Triassic and Jurassic (north-western sector) and Miocene (south-eastern sector) crop out. Conspicuous triangular facets are preserved on Jurassic rocks of the central sector, while short, generally non-incised alluvial fans make the piedmont. The value of the Mountain-front sinuosity index is Smf = 1.24 for the whole mountain front (1.17 and 1.32, respectively, for both segments showing distinct footwall lithology), as obtained by the most conservative procedure. Average valley floor width/height ratios calculated for seventeen gullies crossing the fault are Vf = 0.30 (250 m upstream from the fault trace) and Vf = 0.22 (500 m upstream). These geomorphic indices, together with qualitative features of the escarpment and piedmont landscape, indicate ‘moderate’ to ‘rapid’ fault activity. The range of slip rates estimated from such morphotectonic classification (0.03 to 0.5 mm/y) encloses the range calculated from offset Late Pliocene and Pleistocene stratigraphic markers (0.07 to 0.33 mm/y) Nevertheless, the highest potential slip rate (0.5 mm/y) clearly represents an overestimate: the mountain front could give the impression of an anomalously high level of activity owing to episodic rejuvenation caused by base level drop. info:eu-repo/semantics/openAccess All rights reserved http://www.europeana.eu/rights/rr-f/ 0.471 2011 GEOSCIENCES, MULTIDISCIPLINARY 153 / 170 = 0.9 2011 Q4 T3 info:eu-repo/semantics/article info:eu-repo/semantics/acceptedVersion Lamelas, María Teresa Universidad de Zaragoza (orcid)0000-0002-8954-7517 Simón, José Luis Universidad de Zaragoza (orcid)0000-0003-1412-5245 Soriano, María Asunción Universidad de Zaragoza (orcid)0000-0002-2842-517X 3006 430 Universidad de Zaragoza Dpto. Geograf. Ordenac.Territ. Área Geografía Física 2000 427 Universidad de Zaragoza Dpto. Ciencias de la Tierra Área Geodinámica Externa 2000 428 Universidad de Zaragoza Dpto. Ciencias de la Tierra Área Geodinámica Interna 24, 3-4 (2011), 107-122 Geodin. acta GEODINAMICA ACTA 0985-3111 5016632 http://zaguan.unizar.es/record/168693/files/texto_completo.pdf Postprint 605329 http://zaguan.unizar.es/record/168693/files/texto_completo.jpg?subformat=icon icon Postprint oai:zaguan.unizar.es:168693 articulos driver 2026-02-18-12:27:20 ARTICLE