Acumulaciones fluviales en la Depresión del Ebro: valoración de la validez de una secuencia general

In this work the sequence of fluvial terraces identified in the main courses of the Ebro Basin are exposed as well as the absolute and relative chronology data available at the present moment. Some fundamental factors in the conformation and conservation of these morphologies are analyred, and he validity of a global correlation of fluvial accumulations for the basin from current available information is discussed.En este trabajo se relacionan las secuencias de terrazas fluviales identificadas para los principales cursos de la Depresión del Ebro así como los datos de cronología absoluta y relativa disponibles hasta el momento. Se analizan algunos de los factores fundamentales en la configuración y conservación de estas morfologías y se cuestiona la validez de una correlación general de acumulaciones fluviales para toda la cuenca a partir de la información actual disponible

Thinning of the Monte Perdido Glacier in the Spanish Pyrenees since 1981

Producción CientíficaThis paper analyzes the evolution of the Monte Perdido Glacier, the third largest glacier in the Pyrenees, from 1981 to the present. We assessed the evolution of the glacier's surface area by analysis of aerial photographs from 1981, 1999, and 2006, and changes in ice volume by geodetic methods with digital elevation models (DEMs) generated from topographic maps (1981 and 1999), airborne lidar (2010) and terrestrial laser scanning (TLS, 2011, 2012, 2013, and 2014) data. We interpreted the changes in the glacier based on climate data from nearby meteorological stations. The results indicate that the degradation of this glacier accelerated after 1999. The rate of ice surface loss was almost three times greater during 1999–2006 than during earlier periods. Moreover, the rate of glacier thinning was 1.85 times faster during 1999–2010 (rate of surface elevation change  = −8.98 ± 1.80 m, glacier-wide mass balance  = −0.73 ± 0.14 m w.e. yr−1) than during 1981–1999 (rate of surface elevation change  = −8.35 ± 2.12 m, glacier-wide mass balance  = −0.42 ± 0.10 m w.e. yr−1). From 2011 to 2014, ice thinning continued at a slower rate (rate of surface elevation change  = −1.93 ± 0.4 m yr−1, glacier-wide mass balance  = −0.58 ± 0.36 m w.e. yr−1). This deceleration in ice thinning compared to the previous 17 years can be attributed, at least in part, to two consecutive anomalously wet winters and cool summers (2012–2013 and 2013–2014), counteracted to some degree by the intense thinning that occurred during the dry and warm 2011–2012 period. However, local climatic changes observed during the study period do not seem sufficient to explain the acceleration of ice thinning of this glacier, because precipitation and air temperature did not exhibit statistically significant trends during the study period. Rather, the accelerated degradation of this glacier in recent years can be explained by a strong disequilibrium between the glacier and the current climate, and likely by other factors affecting the energy balance (e.g., increased albedo in spring) and feedback mechanisms (e.g., heat emitted from recently exposed bedrock and debris covered areas).Ministerio de Economía, Industria y Competitividad - IBERNIEVE (project CGL2014-52599-P)Ministerio de Agricultura y Pesca, Alimentación y Medio Ambiente (project 844/2013

Cartografía de zonas probables de aludes en el Pirineo aragonés: metodología y resultados

En este trabajo presentamos tres ejemplos de cartografía de zonas probables de aludes en el Pirineo Aragonés (Canal Roya-Espelunciecha, valle de Ordesa y valle de Pineta) en los que se incluyen aquellas áreas que se han visto, o pueden verse afectadas por avalanchas de nieve. La metodología utilizada, en la que se combina la observación de fotogramas aéreos con el trabajo de campo y, en menor medida, la encuesta sobre el terreno, se basa en la consideración de determinados factores intrínsecos a las vertientes como son el límite altitudinal, el valor de las pendientes, la morfología y rugosidad de las laderas, su orientación y la cubierta vegetal presente en la zona.

Dinámica glacial, clima y vegetación en el Parque Nacional de Ordesa y Monte Perdido durante el Holoceno

[EN] New and more detailed geomorphological, hydrological, vegetational and climatic reconstructions for the Holocene in the PNOMP have been obtained from the pluridisciplinary study of three records (La Larri, La Estiva and Marboré). La Larri paleolake was originated when the Pineta glacier blocked the valley before 35 ka and existed till 11 ka when it was drained when the glacier receded. Marboré Lake record spans the last 11 kyrs. Facies, geochemistry and magnetic properties identify a large glacier influence between 11 and 9.2 ka. The 9.2- 4.1 ka was relatively more humid. The Mid Holocene transition ca 5 – 4.5 ka to more arid conditions was detected in both Marboré and La Estiva. During the last 3 millennia several arid phases occurred (end of the Roman Period, the High Middle Ages, the Medieval Climate Anomaly). The LIA is characterized by higher runoff and colder climate. However, pollen studies indicate a higher human pressure in the mountains during this period. Both, historic global atmospheric contamination and local influx of the mining activities in the Alto Cinca valley are detected in the Marboré record. The Marboré and Monte Perdido glaciers have been receding during the last centuries, with several moraines ascribed to the first phase of the LIA, and a large expansion during the early XXth century. The main factors controlling recent glacier retreat are the increase in maximum summer temperatures and the decrease in snow precipitation in winter.Proyecto financiado por el Organismo Autónomo Parques Nacionales Dinámica glacial, clima y vegetación en el Parque Nacional de Ordesa - Monte Perdido durante el Holoceno (ref: 83/2009). Agradecemos a todo el personal del PNOMP su apoyo para la realización de los trabajos de campo.Peer Reviewe