Papers by Y. Sánchez-moya
Innovación en la producción de cartografía geomorfológica de amplias y variadas superficies. Ecua... more Innovación en la producción de cartografía geomorfológica de amplias y variadas superficies. Ecuador, un caso de éxito Innovative geomorphological cartography generation of large and varied land areas. Ecuador, a success story
El itinerario propuesto discurre por un area de la provincia de Guadalajara, donde es posible ana... more El itinerario propuesto discurre por un area de la provincia de Guadalajara, donde es posible analizar las relaciones entre la tectonica y la sedimentacion durante el Permico y el Triasico. Los materiales de estas edades estan muy bien expuestos y la relacion con las fallas contemporaneas con la sedimentacion es evidente. En el sector de enlace entre el Sistema Central y la Cordillera Iberica se pueden examinar con detalle las caracteristicas de las series del Permico que constituyen el inicio del ciclo de sedimentacion postvarisco y las discordancias que separan el Paleozoico inferior del Permico y, de este, con el Triasico inferior y medio. Una vista panoramica desde el castillo de Riba de Santiuste permite observar el gran espesor de las facies Buntsandstein que alcanza en este sector los 850 m y analizar las relaciones entre el control tectonico y la respuesta sedimentaria al movimiento de las fallas. A pocos kilometros, cerca de la fractura principal que controla el borde occid...
Palynological data from the Buntsandstein of the Reinosa (Santander) and Verbio (N of Palencia) a... more Palynological data from the Buntsandstein of the Reinosa (Santander) and Verbio (N of Palencia) areas, has allowed establishing a Ladiniense-Carniense age for the upper part of these facies. Two palynological assemblages have been identified. The first one is characterized by Triadispora spp., Ovalipollis pseudoalatus and Duplicisporites spp. The second one is characterized by Vallasporites ignacii and Enzonalasporites sp. This age questions the correlation and equivalence of the carbonates that appear in this region, with the Muschelkalk facies of the rest of Spain.
Resumen El estudio detallado de las estratificaciones cruzadas, de sus geometrías, sucesiones, ca... more Resumen El estudio detallado de las estratificaciones cruzadas, de sus geometrías, sucesiones, cambios horizontales y propiedades vectoriales proporciona en muchas ocasiones información inmediata sobre las condiciones en que tuvo lugar la sedimentación. Estas estructuras sedimentarias reflejan condiciones hidrodinámicas específicas y dan información acerca del agente de transporte, la velocidad de sedimentación, de la dirección y sentido de las paleocorrientes, o del medio sedimentario en que se generaron. Desde el punto de vista didáctico son un excelente recurso para que los alumnos aprendan a relacionar los procesos naturales que intervienen en la formación de algunas rocas sedimentarias.
Journal of Iberian Geology, 2009
Triassic carbonate rocks of the western Cantabrian Mountains, northern Spain, have long been attr... more Triassic carbonate rocks of the western Cantabrian Mountains, northern Spain, have long been attributed to the Muschelkalk facies, and as such have been correlated with other Middle Triassic carbonate units of the Iberian Peninsula. Data on palynological assemblages here presented, point to a Ladinian-lower Carnian age of the upper part of the Buntsandstein facies in this area. In addition, the 87Sr/86Sr ratio of the limestones formerly attributed to the Muschelkalk facies indicates a Norian or Norian-Rhaetian boundary age. These findings also imply that the position of the marine coast during the Middle Triassic Tethys transgression should be moved to a more easterly position, in the Basque Country.
Journal of iberian geology: an international publication of earth sciences, 1995
En este trabajo se realiza un estudio de los sedimentos permicos y triasicos que se localizan pri... more En este trabajo se realiza un estudio de los sedimentos permicos y triasicos que se localizan principalmente en el subsuelo de la Cuenca de Almazan, borde E de la Cuenca dcl Duero y borde NW de la Cuenca del Ebro, mediante el analisis detallado de los sondeos y lineas sismicas que existen en estas areas. Esto ha permitido establecer una serie de correlaciones con los materiales equivalentes que afloran en superficie en areas proximas de ambas ramas de la Cordillera Iberica. Las unidades litoestratigraficas establecidas en los afloramientos de la Cordillera Iberica, por autores anteriores, sir ven de referencia para el analisis e interpretacion de los sondeos. Han podido ser caracterizadas en profundidad un total de 14 unidades de las cuales 1 corresponde al Permico inferior, 9 corresponden a materiales en facies Buntsandstein y 4 a materiales en facies Muschelkalk. Estas unidades presentan una distribucion irregular, habiendose establecido tres sectores en el area estudiada en funci...
The Geology of Iberia: A Geodynamic Approach, 2019
The Permian-Triassic rifting represents the first of the two Mesozoic rifting stages recorded in ... more The Permian-Triassic rifting represents the first of the two Mesozoic rifting stages recorded in the Iberian Peninsula. Its first phases of development started during the Early Permian, and were linked to the beginning of the break-up of Pangea, the large, unique and rheologically unstable supercontinent that mainly resulted from the collision of Gondwana and Laurussia. This chapter analyzes this first rifting stage in Iberia in two separate phases, an initial or tectonic phase, and a later mature phase. This analysis focuses on the main Permian-Triassic basins of the Iberian Peninsula: the Pyrenean, Iberian, Catalan, Ebro and Betic basins, as well as the basins located in the present-day Balearic Islands. In order to achieve a better understanding of the analyses of these basins, a multidisciplinary approach has been carried out by 48 researchers, including studies of tectonics, sedimentology, magmatism, mineralogy, geochemistry and paleontology.
Quaternary Science Reviews, 2017
This paper provides a new methodological approach to analyse secular patterns of flooding (magnit... more This paper provides a new methodological approach to analyse secular patterns of flooding (magnitude and frequency) from sedimentary evidence (palaeofloods), taking into account changes in channel geometry, and their links to historical environmental changes and the inherent social and demographic evolution within the catchment. A case study analysis was focused in Rambla de la Viuda (drainage area of 1500 km 2) whose stream flow is related to extreme rainfalls. A 500 years sedimentary archive was reconstructed from eight stratigraphic profiles comprising continuous sequences of slackwater flood deposits interbedded with episodic colluvial and edaphic horizons. Discharge estimates associated to sedimentary flood evidences were obtained from one-dimensional hydraulic modelling. The strati-graphic units were sampled to characterise their geochemical and paleobotanical (phytoliths) contents. Palaeoflood chronology was obtained from radiocarbon and luminescence (OSL) dating, supported by documentary data (written historical documents). A high frequency and high magnitude palaeoflood period took place during the 15 th-middle 16th century, which seem to correlate in time with general wetter conditions. Three short-term environment stability conditions (land use and climatic) also made possible the development of three paleosols. The lowest flood magnitude and discharges in the sedi-mentary record was found between the mid-17th to mid-18th centuries, under prevailing drier environmental conditions. Episodic high magnitude flooding took place at late 18th century, correlating in time with palaeovegetation and geochemical evidences of important changes on land use (deforestation and grazing). Poorer developed soils were found at upper stratigraphic sequences (19th century) char-acterised by thick units of colluvium deposits, usually culminating sequences of short-lived continuous slackwater flood units. Despite of the potential human influence (land-use) on soil hydrology, the long-term behaviour of high magnitude floods (>1000 m 3 s-1) has been stationary over the last 500 years.
Tectonophysics, 2015
the permo-triassic transtensional rifting in the iberian range (ne spain) according to magnetic f... more the permo-triassic transtensional rifting in the iberian range (ne spain) according to magnetic fabrics results, Tectonophysics (2015),
ABSTRACT Understanding regional flood response to climate change is one of the major challenges o... more ABSTRACT Understanding regional flood response to climate change is one of the major challenges of climate change science (IPCC, 2007). Evidence of past flooding from palaeoflood studies over the last three decades indicates that over long-term timescales (centuries to millennia) flood magnitude and frequency varies in response to climatic variability. The precision of palaeoflood chronologies typically enables centennial scale variations to be determined, whilst documentary flood records from the last 500 years indicate that flood frequency may increase over decadal timescales. The increasing resolution of climate change from annually laminated archives, such as ice cores, means that it is inherently difficult to compare palaeoflood records with climate proxies at the desired resolution necessary to investigate whether shifts in flood magnitude and frequency are driven by temperature changes. In this paper the bayesian age modelling of radiocarbon dated palaeoflood deposits is used to interrogate published palaeoflood chronologies. Such age modelling is usually carried out on sediments in which a continuous sedimentation is assumed e.g. lake deposits. By contrast, palaeoflood sequences are formed by individual large, rare events, clustered in certain time periods, which may result in high variability in the rate of deposition. The first aim of this paper, therefore, is to test different Bayesian models to identify the most appropriate for the modelling of palaeoflood deposits. The various modelling approaches used are illustrated using selected palaeoflood sites. The implications of the results for the dating of palaeoflood sequences are discussed. Finally, where refined chronologies are considered an improvement, some preliminary interpretations are made with regards the response of flood magnitude and frequency to climatic variability.
Approach to the sediment production rates through the check dams retention capacity in ephemeral ... more Approach to the sediment production rates through the check dams retention capacity in ephemeral Mediterranean rivers. X. Rodríguez-Lloveras (1), G. Bussi (2), Y. Sánchez Moya (3), A. Sopeña (3), F. Francés (2), G. Benito (1)
We apply AMS techniques in Triassic red beds from the Castilian Branch (Iberian Range, NE Spain),... more We apply AMS techniques in Triassic red beds from the Castilian Branch (Iberian Range, NE Spain), a tectonically inverted basin (during Tertiary) where no penetrative structures associated to compression were originated. Our goal is to differentiate magnetic fabrics developed during the extensional stage and the ones modified during compression. In addition we will try to describe the geometry of the basin and the stress pattern acting during extension. In most cases, we observe typical sedimentary oblate fabrics, with different lineation directions, but with an ENE-WSW oriented maximum, which fits with a transtensional dextral extension regime. Variations in the lineation orientation are probably related to the different orientations of the faults limiting the basin sectors. In a less proportion, we distinguish magnetic fabrics modified by Tertiary compression, with "girdles" developed between intermediate and minimum axes.
Spanish regulations on dam safety recommend the estimation of a return period of 1000 years for t... more Spanish regulations on dam safety recommend the estimation of a return period of 1000 years for the Design Flood and of 10,000 for the Safety Check Flood. The criteria used for the calculations are based on Flood Frequency Analysis (FFA) from gauge record data or on the Probable Maximum Flood (PMF) which is the hypothetical maximum of rainfall turned into runoff. The short gauge records affords little support for the FFA and for the hypothetical PMF, which in addition to the absence of a associated probability, limits the utility of these indices for risk-based dam safety decisions. Palaeoflood techniques are a means of directly assessing the probability of extreme floods and testing the validity of the PMFbased models. In this paper, palaeoflood record was applied to a case study in the Guadalentín river, upstream of the Valdeinfierno reservoir (372 km 2) with a spillway capacity of 550 m 3 s-1. (design flood). In addition, available historical flood data was collected. Palaeoflood data and gauge record, were combined for the FFA, using existing methods for the fitting of distribution functions, such as the maximum likelihood. Palaeoflood analysis provides a discharge of 2350 m 3 s-1 for the design flood (1000yr return period), and 3450 m 3 s-1 for the safety check flood (10,000 yr-return period). The discharge estimated by the PMF is 5786 m 3 s-1 , showing an overestimation of this empirical method. Some recommendations for the calculation of the safety check flood and design flood are provided which can improve existing legislation on dam safety.
The Guadaletín River, located in SE Spain, is considered one of the most torrential rivers in Spa... more The Guadaletín River, located in SE Spain, is considered one of the most torrential rivers in Spain (e.g. the 1879 flood resulted in 777 casualties in the Murcia region; the Puentes dam break in 1802 caused 608 deaths in Lorca). Flash flood magnitude and frequency of the upper Guadalentín River has been reconstructed using documentary sources and geological evidence. Documentary
Sedimentary Geology, 1992
... 257 Elsevier Science Publishers BV, Amsterdam Evolving fluvial architecture during a marine t... more ... 257 Elsevier Science Publishers BV, Amsterdam Evolving fluvial architecture during a marine transgression: Upper Buntsandstein, Triassic, central Spain Araceli Mufioz, Amparo Ramos, Yolanda Sfinchez-Moya and Alfonso Sopefia Departarnento ... (1978) and Mack and James ...
sociedadgeologica.es
Detailed palaeomagnetic sampling has been made of two units of the Middle Triassic in the western... more Detailed palaeomagnetic sampling has been made of two units of the Middle Triassic in the western Cordillera Ibérica in Central Spain. Thermal demagnetization reveals the preservation of characteristic Triassic remanence. A recent overprint is also present, ...
The Holocene, 2011
A new methodology, based on Bayesian age modelling, is presented for the analysis of palaeoflood ... more A new methodology, based on Bayesian age modelling, is presented for the analysis of palaeoflood geochronologies and palaeodischarge data. Bayesian age models were developed, using the Oxcal radiocarbon calibration software, for the geochronologies of three palaeoflood sites in Spain, namely the Gaudalentín, Tagus and Llobregat rivers in SE, Central and NE Spain, respectively. The age–depth plots resulting from the applied Sequence models enabled the construction of flood magnitude-frequency plots through substitution of the original stratigraphic depth data with the associated minimum discharge quantified by hydraulic modelling. The age models presented demonstrate that a Bayesian approach for analyzing Holocene flood magnitude and frequency prevents the loss of geomorphic and hydrologic information inherent in radiocarbon frequency methods previously used in the analysis of palaeoflood data sets. Frequency approaches do not allow proper consideration of flood magnitude information...
Tectonophysics, 2009
Iberian Chain, as well as to produce crusta I pop-ups, such as the Central System, over the non e... more Iberian Chain, as well as to produce crusta I pop-ups, such as the Central System, over the non extended central-western crust of Iberia
Sedimentology, 2002
Cauliflower-shaped nodules are widespread in a single red mudstone bed in the Buntsandstein (Tria... more Cauliflower-shaped nodules are widespread in a single red mudstone bed in the Buntsandstein (Triassic) facies of the Iberian Range. They consist mostly of quartz. dolomite and calcite. but other minerals. such as barite. kaolinite and iron oxyhydroxides, are also present. The nodules are spherical, ovoid or elongate in shape and range from 1 to 8 cm across. The surface of the nodules is irregular, and some show a pedogenic coating of microspar. The sedimentological and petrographic data suggest that the initial anhydrite nodules formed through a progressive increase in the porewater concentration of Ca2+ and 5042-in a vadose environment, occasionally under the influence of pedogenic processes. Partial replacement of the anhydrite by megaquartz occurred under more dilute conditions in the same type of setting, as indicated by the presence of organic filaments on the quartz crystal surfaces. In type A nodules. the dissolution of the innermost anhydrite was complete. and different types of quartz cement filled the porosity. Fracturing and meteoric cementation by calcite and minor amounts of kaolinite were the latest processes affecting these nodules. In type B nodules. the dissolution of the anhydrite was incomplete. inhibiting quartz cementation and enabling later dolomitization of the anhydrite. Dolomitization appears to have been driven by sulphate reduction. as indicated by the presence of bacterial bodies within the dolomite crystals. Dedolomitization and precipitation of barite. kaolinite and calcite spar cements occurred later under the influence of meteoric solutions. The nodules may mark the former locations of the water table and provide evidence for an episode of highly evaporitic conditions throughout wide areas of the basin. Their occurrence reveals not only a complex diagenetic history but is also indicative of palaeogeographic and palaeoclimatic conditions.
Uploads
Papers by Y. Sánchez-moya