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The present study deals with the morphometric quantification of erosion and illustrates the uplift component triggered by denudation (isostasy) in the growth and evolution of a rising orogeny by the application of Airy isostasy concepts. The Gibraltar Arc, located in the Western&ndash, Central sector of the Betic Cordillera, developed an exceptional geological scenario during the Messinian Salinity Crisis since the thin emerged fringe of the uprising Cordillera disconnected the Atlantic and Mediterranean basins, generating a relevant misbalance and asymmetry in the fluvial erosion between the two slopes of the emergent orogeny. Our analysis was applied to 50 individual drainage basins (spatial isostatic units) in the Western&ndash, Central Betic Cordillera, allowing us to obtain individual and bulk estimates for these isostatic parameters. GIS-based numerical estimations were obtained using LiDAR Digital Elevation Models (DEMs) provided by the Spanish Geographical Institute and reconstructed pre-incision surface models obtained from proxy paleo-elevation data, estimated from stratigraphic and geomorphological littoral to shallow marine markers. The obtained values for geophysical relief, denudation plates, erosion/uplift rates and computed accumulated uplift (245&ndash, 407 &plusmn, 20 m) are higher for the ancient Mediterranean slope of the orogen. On the contrary, the Atlantic slope presents an accumulated uplift of only 138&ndash, 236 &plusmn, 20 m, indicating the strong control of the ancient Messinian Atlantic&ndash, Mediterranean water divide. The temporal study of erosion indicates that most of the difference in uplift in the Mediterranean slope was achieved during or soon after the Messinian Salinity Crisis, resulting in mean uplift rates of 0.21 mm/y, but practically null (0.01 mm/y) for the Atlantic slope. The comparison of the geophysical relief models with proxy paleo-elevation data allowed us to assess the current state of the denudation process in the range. The results indicate that, towards the west of the range denudation compensated elevation, and is actively back-feeding isostatic rebound. Therefore, the contribution of external processes to mountain range elevation through isostasy is quantitatively estimated using elevation data. In this case, a relevant part of the surface uplift (50-55%) is undertaken by the orogen. Ultimately, the Messinian Salinity Crisis-related isostatic response to differential denudation may be behind the quaternary westward tilting of Iberia, causing more than 70% of the Peninsula to drain towards the Atlantic.

This paper presents a geomorphological analysis of the littoral zone of the Arosa-Pontevedra estuary mouth and identifies geomorphological units and categorizes them into morphogenetic systems. The different morphogenetic systems are used to establish a comprehensive evolutionary analysis, contrasting the depositional systems found in the continental littoral zone with the marine erosional systems (‘rasas’). The compiled cartography groups the geomorphological units into the following: the lithoestructural morphogenetic system with large-scale forms (domes, inselbergs, residual relief, etc.) and small-scale forms (gnammas, tafoni, channels, etc.); the littoral morphogenetic system comprised of marine (marine terraces, beaches, tidal bars, tombolos and coastal arrows), transition (marshes, lagoons and fan deltas) and eolian (dune systems) settings; the fluvial morphogenetic system with channelled (alluvial, flood plain and river terraces), transition (alluvial fans and alluvial cones) and sheet flood (pediments and glacis) systems; the gravitational morphogenetic system (colluvium); and the alteration morphogenetic system (sand-alteration)., This work has been supported by the research projects CGL2015-67169-P (MINECO-FEDER) and CGL2015-69919-R

This work analyses the chronology of fluvial terrace sequences of the two most important fluvial basins from central Spain draining to the Atlantic Ocean (Upper Tagus and Duero drainage basins). Both basins evolved under similar Mediterranean climatic conditions throughout the Pleistocene and present comparable number of fluvial terraces (16–17) after excluding the higher terrace levels of the Tagus (T1–T5) entrenched in the Rana surface. These higher “ranizo terraces” was formed in response to fan-head trenching in this high alluvial piedmont (+220 m) and therefore not properly controlled by Quaternary fluvial downcutting. The study accomplishes the implementation of multiple regression analyses for terrace height-age relationships. To transform relative terrace heights above the present river thalwegs (i.e. +100 m) in numerical ages a “height-age transference function” has been developed on the basis of preliminary statistical geochronological approaches proposed for Central Spain. The resultant height-age transference function gather 73 published geochronological data for terrace sequences, featuring a 3rd Order Polynomial Function (R2 0.90). This function describes the overall trend of valley downcutting for the last c. 2.3 Ma in Central Spain and is used to assign numerical ages to terrace levels at different relative elevation.

Geomorphology is fundamental to landscape analysis, as it represents the main parameter that determines the land spatial configuration and facilitates reliefs classification. The goal of this article is the elaboration of thematic maps that enable the determination of different landscape units and elaboration of quality and vulnerability synthetic maps for landscape fragility assessment prior to planning human activities. For two natural spaces, the final synthetic maps were created with direct (visual-perceptual features) and indirect (cartographic models and 3D simulations) methods from thematic maps with GIS technique. This enabled the creation of intrinsic and extrinsic landscape quality maps showing sectors needing most preservation, as well as intrinsic and extrinsic landscape fragility maps (environment response capacity or vulnerability towards human actions). The resulting map shows absorption capacity for areas of maximum and/or minimum human intervention. Sectors of high absorption capacity (minimum need for preservation) are found where the incidence of human intervention is minimum: escarpment bottoms, fitted rivers, sinuous high lands with thick vegetation coverage and valley interiors, or those areas with high landscape quality, low fragility and high absorption capacity, whose average values are found across lower hillsides of some valleys, and sectors with low absorption capacity (areas needing most preservation) found mainly in the inner parts of natural spaces: peaks and upper hillsides, synclines flanks and scattered areas. For the integral analysis of landscape, a mapping methodology has been set. It comprises a valid criterion for rational and sustainable planning, management and protection of natural spaces., This work has been supported by the research projects CGL2015-67169-P (MINECO-FEDER) and CGL2015-69919-R.

The Malaga basin contains an important geological record documenting the complex paleogeographic evolution of the Gibraltar Arc before, during and after the closure and desiccation of the Mediterranean Sea triggered by the “Messinian Salinity crisis” (MSC). Proxy paleo-elevation data, estimated from the stratigraphic and geomorphological records, allow the building of quantitative paleogeoid, paleotopographic and paleogeographic models for the three main paleogeographic stages: pre-MSC (Tortonian-early Messinian), syn-MSC (late Messinian) and post-MSC (early Pliocene). The methodological workflow combines classical contouring procedures used in geology and isobase map models from geomorphometric analyses and proxy data overprinted on present Digital Terrain Models. The resulting terrain quantitative models have been arranged, managed and computed in a GIS environment., Departamento de Geología, Universidad de Salamanca, España, Instituto Geológico y Minero de España, España, Departamento de Edafología, Universidad Politécnica de Madrid, España, Departamento de Geología, Universidad de Alcalá de Henares, España, Departamento de Geología y Geoquímica, Universidad Autónoma de Madrid, España

by Witold Zuchiewicz and Jerzy Zasadni (2012) intended for this volume YOUNG TECTONICS OF THE OUTER WESTERN CARPATHIANS IN THE LIGHT OF SOME MORPHOMETRIC INDICES In this paper, we test the applicability of some morphometric indices commonly used in tectonic-geomorphological studies to the area of the Outer Western Carpathians representing an Alpine fold-and-thrust belt. This belt was shaped largely in Miocene times and shows traces of Pliocene-Quaternary tectonic activity consisting mainly in some remnant folding and faulting. This is indicated by scarce examples of faulting within Quaternary strata, numerous cases of clast fracturing owing to palaeoearthquakes of relatively large magnitudes, as well as warping and tilting of Pleistocene and Holocene strath terraces. Analysis of selected morphometric indices (valley floor width-valley height ratio, riverbed gradients, stream length-gradient index, basin elongation ratios and others), conducted for the entire region and some chosen test areas in the westernmost part of the Outer Western AC C EP TE D M AN U SC R IP T ACCEPTED MANUSCRIPT 24 Carpathians, proved their usefulness in detecting zones showing tendencies to young surface uplift. However, in the case of the stream length-gradient index (SL, Hack’s index) a word of caution should be added, since the index is extremely sensitive to lithologic contrasts in the bedrock and its applicability to young tectonic analysis of fold-and-thrust belts appears to be strongly limited. Dr Andrzej Piotrowski, apiot@pgi.gov.pl, Szczecinie Panstwowy Instytut Geologiczny, Szczecin, Poland and Dr Klaus Reicherter, RWTH Aachen University, Germany

Normally in paleoseismology, the study of the tectonic slip-rate is performed in trenches on the fault scarp, or by the estimation of fault movements from the geomorphic features. In this work, we have carried out a paleoseismic analysis of the Benis Fault, located in southeast Spain, combined with a geothermal analysis inside a deep cave related to the fault (−350 m). Thus, we have estimated the last earthquake magnitude and time of occurrence from evidence of ceiling collapse and displaced carbonate blocks inside a cave, which is developed across the fault. The magnitude was obtained from the application of the empirical relationship of the fault parameters and coseismic vertical displacement, yielding a value ranging between M 5.9 and M 6.5. Moreover, we dated this paleoearthquake by the paleontological record of a “Lynx pardinus spelaea”, with an age of 65 ± 18 ka BP. Additionally, we have measured the thermal profile of the Benis Cave (−350 m of depth), from single rock point temperature measurements during 2 years. The temperature profile shows three different parts inside the cave, the shallow heterogeneous thermal zone till 50 m depth; the homogeneous thermal zone 150 m till with constant temperature and the hetero-thermal deep zone, deeper than 150 m and till the deepest zone (350 m). Furthermore, we have estimated the Vertical Geothermal Gradient, 1.85 °C/100 m for the deepest zone (−150; −290 m). The temperature increases with depth, showing a reverse thermal profile in comparison with normal gradients in deep caves. Finally, we have calculated the heat flux of 0.46 mWm., This work is a contribution of the Spanish projects SISMOSIMA CGL2013-47412-C2-2-P and CGL2015-67169-P (QTETCSPAIN-USAL), granted by the MINECO-FEDER Spanish Ministry.

This work performs a geomorphological mapping procedure applied to the evolutionary analysis of the landscape, such that it groups different geomorphological units photointerpreted in large geomorphological domains. This allows greater utility and ease of identification and application in the different multidisciplinary studies of environmental geology and the evolution of the landscape. Geomorphological analysis allows the investigation of the reconstruction of the relief from the processes that have shaped the landscape over time. This work is a tool for the analysis of palaeolandscapes and palaeoreliefs applied to correct environmental and sustainable planning of the territory. The process starts from a morphostructural zoning in which they are grouped according to their erosive and depositional forms and the morphogenetic system to which they belong: structural, fluvial, gravitational, and polygenic. The procedure is applied to two natural parks: Batuecas and Quilamas, differentiating 18 geomorphological domains. The 2D and 3D cartographies have been implemented in virtual 3D balloons allowing a greater ease of landscape analysis in the spatial distribution of the different units over orthophotographs. The morphological and chronological evolution of the evolution of the landscape is established from the relative age of the lithological units and the geomorphological domains, as well as by their geospatial position. Georeferenced digital mapping complies with the Inspire directive for these natural spaces., This research was funded by projects from the Ministry of Economy and Competitiveness CGL2015-67169-P and CGL2015-69919-R., We acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI).

Las intervenciones arqueológicas llevadas a cabo durante los años 1996 en Tafesa, 2005 en el yacimiento Hospital 12 de Octubre y 2006 en la desembocadura del arroyo Butarque (Villaverde-Barrio de Butarque) situados al sur de la ciudad de Madrid (España), han aportado nuevos conjuntos líticos contextualizados estratigráficamente en los depósitos fluviales pleistocenos correspondientes al tramo inferior del valle del río Manzanares. Los yacimientos arqueológicos analizados se sitúan geomorfológicamente en la denominada “Terraza Compleja del Manzanares” (TCMZ), la cual constituye un nivel fluvial engrosado (20-15 m de potencia) situado entre +22-16 m sobre el cauce actual del río, a lo largo de su margen derecha. Este nivel fluvial ha sido tradicionalmente considerado de edad Pleistoceno medio en base a la industria achelense y complejos faunísticos encontrados en sus niveles inferiores. Ciertamente, Tafesa es un yacimiento situado en la parte inferior-media de la terraza de +22 m con industria achelense y fauna de Pleistoceno medio. Por el contrario, los niveles superiores de esta misma terraza en los sectores del 12 de Octubre y Villaverde-Butarque se encuentran asociados a industrias del Paleolítico inferior y medio ya pertenecientes al Pleistoceno superior, como sugieren el conjunto de dataciones OSL y TL existentes para la zona. Los datos analizados en este trabajo indican que el desarrollo de este nivel de terraza engrosado comienza durante la parte final de Pleistoceno medio y abarca todo el Estadio Isotópico OIS 5, ya dentro del Pleistoceno superior, The archaeological works developed during the years 1996 in the site of Tafesa, 2005 in the 12 de Octubre Metro Station site and 2006 in the confluence of the Butarque Stream (Villaverde-Barrio de Butarque site) located south of the Madrid City (Spain), have provided new lithic assemblages. These assemblages have been stratigraphically contextualized in the Pleistocene deposits of the Lower Manzanares river valley within the so-called “Manzanares Complex Terrace” (TCMZ). This fluvial terrace constitutes an anomalous thickened (20-15m) deposit at +22-16m above the present river thalweg mainly developed along the right (southern) valley margin. This fluvial level has been traditionally considered of middle Pleistocene age on the basis of the acheulian lithics and faunal assemblages typically located within its lower stratigraphic layers. Certainly, the Tafesa is a fluvial terrace site at +22 m with acheulian industry and middle Pleistocene faunal remains at its lower sedimentary sequence. However, the upper sedimentary levels of this same terrace in the 12 de Octubre y Villaverde-Butarque sites throw lithic assemblages of the lower and upper Paleolithic belonging to upper Pleistocene, as suggested by the available set of TL and OSL dates for the zone. The analyses developed in this study indicate that the development of this thickened fluvial terrace started during the end of the middle Pleistocene, but also comprise the whole Oxygen Isotopic Stage OIS 5 during the upper Pleistocene.

Sedimentary successions of non-marine basins can be considered in terms of accommodation space and sedimentary supply changes. Changes in accommodation space controlling the large-scale architecture of non-marine basins are different in areas with high and low sedimentary supplies. Uplift of intrabasinal monoclines and anticlines reduced the available accommodation space, resulting in changes in both the geometry of the depositional sequences and the large-scale architecture of fluvial, mudflat and shallow carbonate lacustrine deposits. Main drainage fluvial systems record areas with a high sedimentary supply, while mudflats and shallow fluctuating lakes represent areas that received less sediment. Two end members in the large-scale architecture of main drainage fluvial system in the Almazan Basin (Spain) are: (i) ribbon-shaped channel fills with low interconnectivity which pass laterally into mudflats dominated by mudstones and evaporites and into palustrine and shallow carbonate lacustrine deposits (mainly in the A2 depositional sequence); and (ii) sheet-like channel fills with high interconnectivity laterally correlated with stacked calcretes in the marginal mudflats (in the upper part of A3). Ribbon-shaped channel fills formed in areas of high accommodation space and sheet-like channel fills formed in areas of reduced accommodation space.

The tectonic Guadalentin Depression is an elongated Quaternary sedimentary basin generated by a system of left-lateral strike-slip faults on the eastern Betic Cordillera. The Lorca-Alhama de Murcia fault (LAF) is the most relevant structure, controlling the 100-km-long western margin of the depression with a prominent mountain front. Climatic conditions are semiarid, and sedimentation is dominated by alluvial fans. The interaction between tectonics, alluvial sedimentation, and climate results in the development of widespread tectonic landforms and alluvial fan surfaces with different degree of calcrete development. The variable morpho-sedimentary arrangements record different styles of faulting and uplift history on the range front faults. Large fans occur associated with the main gaps and step-overs between the different fault segments bounding the Quaternary basin (e.g. Lorca Fan). Telescopic fan sedimentation under limited distal aggradation eventually turned into distal trenching throughout the late Holocene. This geomorphic evolution constitutes a good example of the transformation of the ancient main fan-feeding channel into a true fluvial channel (present-day Guadalentin River) linked to a well-preserved Late Bronze geoarcheological record.

Three-dimensional patterns of soft-sediment deformation, affecting middle Pleistocene fluvial deposits in the Lower Manzanares Valley (SW Madrid City), are reported. They promote a small-scale hummocky topography, defined by different-sized domes, mud volcanoes, wavy ridges and fissures on an ancient flood plain surface. Related channel fill deposits are pervasively dewatered, indicating liquefaction. The sedimentological context reveals that the deformation of both floodplain surface and channel-fill deposits, were contemporaneous (singular deformed level) and generated at, or near, the ground surface; this rules out the possibility of sediment-loading and indicates a possible earthquake-induced origin.

Active tectonics within the Upper Tagus Basin is related to the lithospheric flexure affecting the Palaeozoic basement of the basin. This flexure displays NE-SW trending. Besides, this structure is in agreement with the regional active stress field defined by the maximum horizontal stress with NW-SE trending. In this tectonic framework, irregular clusters of instrumental seismicity (Mw< 5.0) fade in the zone bounded by the Tagus River and the Jarama River valleys. These clusters are related to major NW-SE trending faults of suspected strike-slip kinematics. Moreover, reverse faults with NE-SW trending are affected by the strike-slip system as well. Despite the reverse faults are in agreement with the present SHMAX orientation, though, they apparently are blocked as seismogenic sources (scarce instrumental seismicity recorded today). In addition, we have determined the regional and local stress/ strain fields and two different fracture patterns were observed. Hence, we have divided the area in two zones: (1) the lateral bands of the basin, defined by reverse faulting (NE-SW trending) and strike-slip faulting (NW-SE trending) and (2) the central zone of the basin characterized by shallow normal faulting and NE-SW trending strike-slip faults. Furthermore, surface faulting and liquefaction structures are described affecting Middle to Late Pleistocene fluvial deposits, suggesting intrabasinal palaeoseismic activity (5.5 < M < 6.5) during the Late Quaternary. The obtained structural and tectonic information has been used to classify and characterize the Upper Tagus Basin as a semi-stable intraplate seismogenic zone, featured by Pleistocene slip-rates < 0.02 mm/yr. This value is low but it affords the occurrence of Pleistocene paleoearthquakes.

Instrumental and historical seismicity in the Albacete province (External Prebetic Zone) has been scarcely recorded. However, major strike-slip faults showing NW-SE trending provide geomorphologic and paleoseismic evidence of recent tectonic activity (Late Pleistocene to Present). Moreover, these faults are consistently well oriented under the present stress tensor and therefore, they can trigger earthquakes of magnitude greater than M6, according to the lengths of surface ruptures and active segments recognized in fieldwork. Present landscape nearby the village of Hellin (SE of Albacete) is determined by the recent activity of the Pozohondo Fault (FPH), a NW-SE right-lateral fault with 90 km in length. In this study, we have calculated the Late Quaternary tectonic sliprate of the FPH from geomorphological, sedimentological, archaeoseimological, and paleoseismological approaches. All of these data suggest that the FPH runs with a minimum slip-rate of 0.1 mm/yr during the last 100 kyrs (Upper Pleistocene-Holocene). In addition, we have recognized the last two major paleoearthquakes associated to this fault. Magnitudes of these paleoearthquakes were gretarer than M6 and their recurrence intervals ranged from 6600 to 8600 yrs for the seismic cycle of FPH. The last earthquake was dated between the 1st and 6th centuries, though two earthquakes could be interpreted in this wide time interval, one at the FPH and other from a far field source. Results obtained here, suggest an increasing of the tectonic activity of the Pozohondo Fault during the last 10,000 yrs., Instituto Geológico y Minero de España, España, Universidad Michoacana de San Nicolás de Hidalgo, México, Facultad de Ciencias, Universidad Autónoma de Madrid, España, Departamento de Geología, Escuela Politécnica Superior de Ávila, Universidad de Salamanca, España, United States Geological Survey, Estados Unidos

Rodríguez-Ramírez and Yáñez-Camacho (2008), Rodríguez-Vidal et al. (2009) and Rodríguez-Ramírez et al. (2009) have kept an ongoing discussion about the validity of radiocarbon ages in reconstructing Holocene palaeogeographical models in the Gulf of Cadiz. The discussion considered the validity and correctness of the ΔR value to beused in the area to calibrate radiocarbon ages ofmarine samples. These papers suggest that theΔR value proposed by Lario (1996) and Dabrio et al. (1999, 2000) is erroneous, and consequently, that all the evolutionary models based on radiocarbon ages from marine samples that have been proposed in this area since 1996 must be revised.However, the papers commentedhere use erroneously the R, regional R andΔR values.After reviewing the published data, it is apparent that the most reliable values of ΔR in the Gulf of Cadiz for middle-late Holocene samples range between ΔR=35±85 yr and ΔR=95±15 yr. This means that the values used in Lario (1996) and Dabrio et al. (1999, 2000) fall in this range, and also that the calibrated ages used by several authors adopting these values are fully reliable. Calibrations using ΔR values inside this range do not yield significant differences in terms of geological age owing to the magnitude of errors resulting from the methods employed.

Digital analysis of torrential gullies (‘barrancos’) deeply incised into the volcanic Island of Gran Canaria (Canary Islands) allows us to extract the longitudinal profiles and pre-incision surfaces for individual basins, from which morphometric parameters (length, elevation, area, slope) have been calculated. Other derived parameters, such as ridgeline profiles, maximum incision values, volume removed by fluvial erosion, geophysical relief and isostatic uplift, have also been computed. Based on K/Ar ages for the island, well-constrained incision-uplift rates have been calculated by means of the combination of different methodological approaches commonly used in orogens and large mountain ranges. The geomorphological and morphometric analyses reveal that the island is clearly divided into four environmental quadrants determined by the combination of a couple of key-factors: the age of the volcanic surfaces and the climatic conditions. These factors determine a young sector covered with Plio-Quaternary platform-forming lavas (finished at 1.9–1.5 Ma) evolving under contrasting wet (NE) to dry (SE) climates, and an older sector, conserving the residual surfaces of the Miocene shield building (14.5–8.7 Ma) at the ridgelines, also subjected to wet (NW) and dry (SW) climates. Incision is related to the age zonation of the island. Maximum incisions (

The Lorca alluvial fan (SE Spain) constitutes an excellent example of transition from alluvial to fluvial sedimentary environments in a semiarid region. The fan body represents a large gently-sloping alluvial fan of mainly sandy–silty composition. It is presently dissected throughout its length by the Guadalentín River, which worked as the main fan channel and still operates as a torrential rambla-type channel responsible for historic large flood events. Three different outcrops are analysed at fan-apex, mid-fan and distal-fan locations, taking also into account the different inset terrace levels developed within the main fan trench at + 8–9 m, + 5–6 m, + 3–4 m and + 1–2 m above the present thalweg. Available radiocarbon data and archeological remains collected in fan sediments and inset terraces enable the construction of a preliminary hypothesis about the progressive incision of the fan body from pre-historical to historical times. Proximal fan aggradation took place during the Early Holocene before ~ 7900–7700 cal. yr. BP and continued until the Late Neolithic to Calcolithic Period (~ 5500–4200 cal. yr. BP) when the fan surface stabilised, and channel incision generated a first fanhead trench. Subsequent infilling of the fan trench led to the development of the upper terrace level (+ 8–9 m) which merged with the palustrine environments 23 km downstream of Lorca, feeding distal fan lobes during Late Bronze Age and Post-Roman times. The second terrace level (+ 5–6 m) is a cut & fill episode of about 5 m thickness developed from Roman times, and dated to ~ 1700 to 950 cal. yr. BP. The geometry and altimetry of the upper terrace level, together with the occurrence of different steps in the longitudinal profile of the river at mid to distal fan locations, strongly suggest that the incision of the ancient fan channel was assisted by intersection point headcut development (sensu [Harvey, A.M., 1978. Dissected alluvial fans in southeast Spain. Catena 5, 177–211.]) at proximal-mid fan locations, but by headward erosion exerted by neighbouring drainage basins at distal palustrine environments. Therefore, the Lorca fan exemplifies the behaviour of large-sized fans in its transition from pure alluvial environments to fluvial ones, and its eventual incipient integration into a regional drainage network subject to a dynamic base-level during the historic period., This work has been supported by the Spanish DGES Projects CGL2005-04655/BTE and CGL2005-01336/BTE. The authors are grateful to the constructive comments of Martin Stokes (Plymouth, UK), Francisco Gutiérrez (Zaragoza, Spain), Andy Plater and Adrian Harvey (Liverpool, UK).

Se presentan los primeros resultados de los proyectos de investigación dirigidos al análisis cronoestratigráfico de las terrazas del río Tajo en el entorno de Toledo. El estudio se ha centrado en niveles fluviales del Pleistoceno Medio y Superior con yacimientos paleontológicos y achelenses con valoración tecnológica general similar al conjunto lítico de Pinedo (colección Máximo Martín Aguado). En el presente trabajo se incluyen las dataciones por IRSL y AAR de los niveles de terraza de +25−30 m que contienen los yacimientos achelenses de Pinedo y Cien Fanegas. Las edades IRSL obtenidas (>280 ka y 292±17 ka) indican que la terraza y los yacimientos que contienen se formaron durante los estadios isotópicos MIS 9 y/o MIS 8, siendo correlacionables con la Unidad Arganda II en el valle del Jarama, aunque Pinedo podría representar parcialmente a la Unidad superior de Arganda I (MIS 11–MIS 9). La datación AAR obtenida para la Unidad superior de Pinedo indica una edad de 226±37 ka. Aunque esta edad ha de tomarse con precauciones debido a la escasa contextualización estratigráfica y los bajos niveles de dentina de las muestras analizadas, podría indicar que el depósito de la terraza estudiada continuó hasta bien entrado el MIS 7, como también parece suceder en el Jarama (Valdocarros). En el tramo del valle analizado los procesos de sobre-sedimentación ligados a los procesos de subsidencia de las evaporitas del Neógeno (aguas arriba) y la existencia del nivel de base local impuesto por el Meandro Encajado de Toledo (aguas abajo), favorecieron los procesos de agradación fluvial sobre los de encajamiento. El método de datación utilizado (post IR–IRSL) ha permitido obtener la edad más antigua hasta la fecha sobre sedimentos fluviales arenosos en la Cuenca del Tajo, This study presents the first geochronological data from several research projects focused on the chronostratigraphy of the Tagus fluvial terraces in the environs of Toledo city (Central Spain). The research is centered on Middle to Late Pleistocene fluvial terraces with palaeontological and Acheulean sites of similar Palaeolithic technology than those showed by the lithic assemblage of the Pinedo site (Máximo Martín Aguado Collection). This study includes the first IRSL and AAR datings for the fluvial levels at +25−30 m present in the Acheulean sites of Pinedo (Toledo) and Cien Fanegas (Aranjuez). The obtained ISRL dates (>280 ky and 292±17 ky) indicate that these fluvial levels and hence their associated Palaeolithic sites, were formed during the marine isotopic stages MIS 9 and MIS 8, and thus it is possible to correlate them with the Arganda II Unit of the adjacent Jarama valley. However, data from Pinedo suggest that this Acheulean site probably also correspond to the upper Arganda I Unit of the Jarama valley (MIS 11–MIS 9). Although the AAR date (226±37 ky) obtained for the Upper unit of Pinedo has to be carefully considered (due to the scarce stratigraphic data and the low dentine levels found in the Equus sp. analyzed samples), it could indicate that sedimentation of the studied terrace level reached the MIS 7, as may also occur in the Jarama valley (Valdocarros site). In the analyzed sector of the Tagus valley, continuous fluvial sedimentation was favored by the occurrence of Neogene evaporites karst-linked subsidence (upstream) and the presence of an outstanding internal base-level represented by the bedrock incised meander of Toledo (downstream). The dating method used in this study (post-IR- IRSL) has allowed us to obtain the oldest date from fluvial sandy deposits in the Tagus fluvial basin up to the present time

This paper examines the lower reach of the Manzanares river valley between Villaverde and its confluence in the Jarama river. In this zone the valley is asymmetric with the development of large escarpments (on gypsums) at the left bank and extensive fluvial terraces on its right one. Among the different fluvial levels the most representative is a complex (thickened) one labelled as TCMZ (+ 16-22 m). This terrace is constituted by at least five fluvial meandering sequences composed of white arkoses (Mz). Younger sequences of mixed nature (arkoses + lithoarenites: Mx levels) develop between + 15 and + 8 m, overlapping the TCMZ, and displaying a more braided character. During the development of the different Mz and Mx levels there was a relevant participation of lateral deposits coming from the main tributaries (Butarque and Culebro), gypsum escarpments (colluviums) and/or from the reelaboration of earlier terrace scarps (glacis). The TCMZ is the highest terrace leve1 in this sector, working additionally as the watershed of the Manzanares river valley (another anomaly). Al1 these anomalous characters are consequence of the system response to the river capture of the Manzanares by the Jarama river during the middle Pleistocene. The palaeontological and archaeological content of the TCMZ suggest that this thickened terrace developed between the OIS 10 (?) and OIS 5. A relevant paleoseismic crisis during the early OIS 5 predates the first major incision period after the river capture. Cold resistant faunas and mousterian relics are characteristic in the Mx terrace levels, being possible to assign their development between the OIS 4 and OIS3. Whatever the case, the intervening cut & fill episodes shaping the fluvial landscape during the Late Pleistocene, hardly can be related to eustatic changes in the Tajo river-mouth at Lisbon (ea. 650 km away). A realistic understanding of river valley evolution in the studied zone, should conjugate climatic changes (limiting the water and sediment supply during the end of cold periods) with relevant neotectonic and karstic activity, feedback by significant intrabasinal headward erosion processes from the late Middle Pleistocene.

Tectonic activity of SE Spain is evaluated through the application of a general morphometric analysis over 17 different mountain fronts. The selected fronts are distributed along the two most prominent crustal-scale structures of the Mediterranean sector of Spain: The Eastern Betic Shear Zone (EBSZ) and the Valencia Trough. Geomorphic indexes used in this study are Mountain-front sinuosity index (Smf) and Valley floor/width ratio (Vf). This work is largely based on the Smf/Vf regression analysis of the studied fronts together with previous available data from SW USA. The development of mountain fronts in both different lithologies and tectonic contexts enabled characteristic morphometric signatures for different activity scenarios (tectonic activity classes) to be obtained. This study thus indicates that variations of mountain front geomorphology triggered by different styles of faulting can be detected by morphometric analysis. It is demonstrated that discrete uplift rates of 0.15-0.08 m/ka are sufficient to keep relatively low Smf values down to 1.4 in Active fronts (Class 1). Taking into account the reported uplift rates and preliminary palaeoseismic data for some of the Class 1 studied fronts, recurrence periods for surface rupture events can be theoretically bracketed for SE Spain. Recurrence periods for Class 1 fronts could theoretically range between 10,000 and 12,500 years for maximum slip conditions, and 1750 and 2600 years for minimum slip conditions. Inactive fronts (Class 3) develop under uplift rates down to 0.03 m/ka, and tested recurrence intervals for rupture events range between 25,000 and 50,000 years. Class 2 fronts of intermediate characteristics and activity display uplift rates between 0.07 and 0.03 m/ka., This work has been supported by the Spanish DGES Projects PB98-265 (USAL) and PB98-514 (CSIC). The authors wish to thank M. Stokes, R. Basili and A. Mather for useful comments on earlier versions of the manuscript.

Neotectonic behaviour of the Eastern Betics (southeastern Spain) has been controlled by the presence of a large, left-lateral shear zone. This is an intraplate transcurrent zone, probably decoupled by a mid-crustal detachment horizon. The morphological expression of this crustal structure is a sigmoidal corridor in which the main Quaternary basins are located. Three types of morphostructural domains can be distinguished in the sigmoidal corridor: the central segment, and the northern and southern terminal splays. The central segment is characterized by wrench tectonics, whilst the southern and northern terminal splays are controlled by transtensional and transpressional tectonics, respectively. The Quaternary morphostructural pattern is only the more recent picture of the tectonic processes that have controlled the late orogenic evolution of the Eastern Betics: the indentation of the Aguilas arc, accompanied by thin-skinned thrusting and tectonic escape in its easternmost sector; and extensional collapse, accompanied by thin-skinned stretching, in its westernmost sector.

The analysis and study of geomorphological features such as: sequence and geometrical disposition of Quaternary geomorphological units; hanging valleys; captures, straight scarps; triangular facets; tilted and deformed deposits..., together with the application of geomorphic indices such as: Stream gradient index; mountain front sinuosity index and ratio of valley-floor width to valley height, all of them indicators of recent tectonic activity, constitute the basis for the realization of a neotectonic cartography. Likewise an analysis of the longitudinal profiles of the several rivers crossing across the studied area and their sinuosity, has been made. From all that, it can be deduced that during the Quaternary the neotectonic activity in the centresouthern sector of the Madrid Basin has been important, mainly during the early-middle Pleistocene transit, when the capture of the River Manzanares by a tributary of the River Jarama, is produced by the southwestward-tilting of the La Maranosa block. Most of the geomorphological features indicators of neotectonics are associated to the large gypsum scarps bounding the main rivers, and are developed troughout the whole Quaternary, including the Holocene. On the other hand the study of the longitudinal profiles of the rivers shows a marked deviation from the theoretical equilibrium profile, being all of them affected by numerous inflections which in many cases correspond to the passing of faults perpendicularly to the river floor. Likewise the sinuosity degree of the rivers is conditioned at a small scale, by the passing of faults, or tectonic activity lines, parallel or perpendicular to the valley.