Person:
Ureta Gil, María Soledad

First Name

María Soledad

Last Name

Ureta Gil

URI

https://hdl.handle.net/20.500.14352/84085

Affiliation

Universidad Complutense de Madrid

Faculty / Institute

Ciencias Geológicas

Area

Paleontología

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Now showing 1 - 10 of 33

Project number: 292
Rutas geológicas virtuales como recurso educativo abierto (open access) en asignaturas de Geología Aplicada
(2016) Herrero Fernández, María Josefa; Álvarez Sierra, María De Los Ángeles; Ureta Gil, María Soledad; Castiñeiras García, Pedro; Arribas Mocoroa, José; Escavy Fernández, José Ignacio; López Acevedo, Francisco
Iron-coated particles from condensed Aalenian-Bajocian deposits: evolutionary model (Iberian Basin, Spain)
(Journal of sedimentary research, 2012) García Frank, Alejandra; Ureta Gil, María Soledad; Mas Mayoral, José Ramón
Condensed intervals provide a framework to study evolution of iron-coated particles. This study examines the ironrich particles contained in the condensed carbonate deposits spanning from uppermost Toarcian to lower Bajocian in the northwestern Iberian Range (northern Spain), to unravel the controls on geochemical changes in the basin by determining variation in mineralogy and REY (rare earth elements and yttrium) as potential predictors of provenance. The articles are composed mostly of the ferrous phyllosilicate berthierine, and by Fe-oxyhydroxide goethite. Depositionally, iron-rich particles occur at specific horizons, and display changes in character, from iron cortoids (Stage 1) in lowest Aalenian sediments, passing to small-sized iron ooids (Stage 2) in early Aalenian strata and to more complex iron-grain aggregates and larger iron ooid–oncoid mixed particles (Stage 3) in the middle–upper Aalenian succession. In the lower Bajocian sediments that represent the most condensed interval, diagenetic processes strongly affected previously iron-coated particles. The genesis of the diverse suite of iron-rich particles is explained by petrographic and mineralogic studies revealing oscillation in redox conditions. Berthierine genesis is linked with suboxic conditions below the water–sediment interface. Subsequent periods of low rates of sediment accumulation allowed the exhumation of particles, and exposing them to oxic conditions that favored goethite formation. Definitive burial led to the development of isopachous circumgranular berthierinic cement rims and dissolution and replacement. Studies of REY and comparison with iron-rich samples of diverse provenance suggest a conceptual model for geochemical evolution of these deposits. The lack of both contemporaneous soil deposits and evidence of subaerial exposure in this arid paleoclimatic setting rule out weathering processes as the main source of iron. Instead, geochemical indexes (Y/Nb and Y/La ratios) suggest that coeval Iberian volcanism was the most plausible iron source. The sedimentological, mineralogical, and chemical attributes of these iron deposits provides proxies to interpret redox and geochemical fluctuations and integrate all the data in an evolutionary model. Variations in REY patterns offer a framework for correlation at both local and subregional scales. Likewise, as this study provides new geochemical data for the Aalenian period, including the Fuentelsaz GSSP worldwide reference section, it enhances knowledge of the evolution of the westernmost Tethyan basins and the significance of widely distributed oolitic ironstones. The data collectively reveal how the REY signature of condensed sediments can be used to obtain detailed information on the geochemical and paleoceanographic conditions of depositional basins.
Latest Toarcian-earliest Bajocian (Jurassic) Grammoceratinae (Hildoceratidae, Ammonitina) of the western Tethys: Their palaeobiogeographic and phylogenetic significance
(Geobios, 2012) Sandoval Gabarrón, José; Henriques, María Helena Paiva; Chandler, Robert B.; Ureta Gil, María Soledad
Grammoceratinae (Hildoceratidae, Ammonitina) abound in the Toarcian strata of many western Tethyan localities, especially the Subbetic and Lusitanian basins (of southern Spain and central western Portugal, respectively). They decline through the Aalenian and disappear by the lowermost Bajocian. The genera Asthenoceras, Vacekia (subgenera Vacekia and Nadorites) and Fontannesia are traditionally considered as the last Grammoceratinae, with species of Osperleioceras occurring in the uppermost Toarcian. Grammoceratinae are common in the eastern Pacific, especially Oregon and Alaska where Asthenoceras is abundant. They also occur in the eastern Tethys (Thailand). Although studies of Toarcian to early Bajocian Subbetic and Lusitanian grammoceratins already exist, new material from these and other palaeogeographic areas (England, Portugal and Spain) is revised here. A new genus, Linaresites nov. gen. (for Fontannesia montillanensis Linares and Sandoval) and two new species (Vacekia striata Henriques, and Asthenoceras taverai Sandoval) are described. Another form, ‘‘Asthenoceras’’ sp. A is described and let in open nomenclature. Temporal analysis of Aalenian to early Bajocian Grammoceratinae demonstrates a progressively more evolute morphology through time, sometimes coupled with size reduction. Palaeogeographic evidence suggests that during the early Middle Jurassic, western Tethys and eastern Pacific were temporarily well connected, possibly through the Hispanic Corridor, as demonstrated by the similarity between Tethyan and eastern Pacific Grammoceratinae.
Características de la plataforma carbonatada del Dogger en el sector meridional de la Sierra de la Demanda (Soria)
(Coloquio de Estratigrafía y Paleogeografía del Jurásico de España (3. 1988. Logroño, La Rioja), 1988) Fernández López, Sixto Rafael; Gómez Fernández, Juan José; Ureta Gil, María Soledad; Goy, Antonio
En el Dogger de facies carbonatadas en la región Talveila-Las Fraguas han sido caracterizadas varias secuencias y discontinuidades sucesivas, vá1idas para el sector meridional de la Sierra de la Demanda y susceptib1es de ser comparadas con las de otras regiones de la Cuenca Ibérica. Como discontinuidades regionales, debidas a cambios importantes en la dinámica y con figuración de la cuenca, cabe destacar la correspondiente al tránsito Bajo-ciense-Bathoniense, así como las de la base del Bajociense y del Aa1eniense. Los materiales del Aa1eniense constituyen tres secuencias que presentan tendencia general hacia un espesor cada vez menor así como polaridad regresiva y que están limitadas por discontinuidades coincidentes con los límites de las biozonas. Durante el Bajociense, en este sector de la plataforma se desarrolla un sistema biosedimentario dominado por bioconstrucciones de espongiarios y en el que predominan las secuencias de somerización. Las condiciones de mayor estabilidad ambiental, y siempre dentro de medios de plataforma externa somera, se alcanzaron durante el Biocrón Humphriesianum. Parece ser que el estado de máxima regresión durante el Bajociense superior se alcanzó en el Biocrón Garantiana y fue seguido por una ruptura del equilibrio sedimentario de la cuenca durante el Biocrón Parkinsoni. Dicha ruptura corresponde al inicio de una fase de somerización generalizada en la Cuenca Ibérica. Durante el Bathoniense se registra una reestructuración de la plataforma, abundan las facies someras de alta energía, se desarrollan secuencias de acreción lateral y la plataforma de carbonatos se ve progresivamente invadida por materiales terrígenos hasta convertirse en una plataforma predominantemente siliciclástica.
Aalenian Tmetoceras (Ammonoidea) from Iberia: taxonomy, habitats and evolution.
(Advancing Research on Living and Fossil Cephalopods: Proceedings of the IVth International Symposium on Cephalopods: Present and Past, held in Granada, Spain, July 14-18, 1996, 1999) Fernández López, Sixto Rafael; Henriques, María Helena Paiva; Linares Rodríguez, Asunción; Sandoval Gabarrón, José; Ureta Gil, María Soledad; Olóriz Aguilera, Federico; Rodríguez Tovar, Francisco J.
Several hundred Aalenian Tmetoceras from the Iberian Peninsula (N Lusitanian Basin, Asturias, Basque-Cantabrian Basin, NE Cameros, NW Iberian Basin, Aragonese Platform, Tortosa Platform, Castilian Platform, Majorca and Betic Basin) have been reviewed. Two species of Aalenian Tmetoceras have been identified on the basis of morphological, biochronological and palaeobiogeographical data: T. scissum and T. regleyi. T. scissum was dominant among the Tmetoceras populations developed in the Betic and Lusitanian basins during Opalinum, Murchisonae and Bradfordensis biochrons. Populations composed by evolute individuals of T. scissum inhabited shelfal or oceanic environments. A chronocline, from rectiradiate and primitive forms to flexicostate and derived forms, can be recognized in these populations of T. scissum. In contrast, shallow epicontinental platforms were inhabited by involute individuals of T. regleyi. This second species was phyletically derived from T. scissum, representing an adaptive radiation from populations of shelfal or oceanic basins to populations of epicontinental platforms.
The Global Boundary Stratotype Section and Point (GSSP) of the Toarcian-Aalenian Boundary (Lower-Middle Jurassic)
(Episodes, 2001) Cresta, S.; Goy Goy, Antonio; Ureta Gil, María Soledad; Arias Fernández, María Del Carmen; Barrón López, Eduardo; Bernard García, Julio; Canales Fernández, María Luisa; García Joral, Fernando; García Romero, Emilia; Gialanella, P.R.; Gómez Fernández, Juan José; González, J.A.; Herrero Matesanz, M. De La Concepción; Martínez Gutiérrez, Gemma; Osete López, María Luisa; Perilli, Nicola; Villalaín, J.J.
The Global Boundary Stratotype Section and Point (GSSP) for the Aalenian Stage, formally defined at the base of bed FZ107 in the Fuentelsaz section, Castilian Branch of the Iberian Range (Spain), has been ratified by the IUGS. Multidisciplinary biostratigraphical data, based on ammonites, brachiopods, ostracods, bivalves, foraminifera, calcareous nannofossils assemblages and palynomorphs, assure worldwide correlations; magnetostratigraphic data increase this correlation power. The position of the boundary coincides with the first occurrence of the ammonite assemblage characterized by Leioceras opalinum and Leioceras lineatum and corresponds with a normal polarity interval correlated with the up-to-date Jurassic magnetic polarity time scale (Gradstein and others, 1994; Ogg, 1995).
Las sucesiones de braquiópodos en el tránsito Lías-Dogger en la Cordillera Ibérica
(Cuadernos de geología ibérica, 1990) García Joral, Fernando; Goy Goy, Antonio; Ureta Gil, María Soledad
Durante el tránsito Lias-Dogger se producen cambios en las asociaciones de braquiópodos, que han sido atribuidos por algunos autores a importantes eventos de renovación en las faunas de este grupo. En la Cordillera Ibérica se aprecian modificaciones importantes en las asociaciones del Toarciense superior y Aaleniense inferior La existencia de numerosas secciones con materiales de este intervalo que muestran un notable desarrollo, ha permitido describir de forma precisa la distribución estratigráfica de las especies de braquiópodos en diferentes sectores de la cuenca (Fig. 1) y analizar de qué manera inciden las facies en la distribución de las asociaciones (Fig. 2). Entre los Rhynchonéllidos. R. goyi aparece en la parte superior de la Zona Pseudoradiosa o en la parte inferior de la Zona Aalensis. En ambientes donde la sedimentación es margosa es sustituida en la parte media o superior de la Zona Aalensis por H. cynorephala, que a su vez es sustituida por G. subobsoheta cuando se produce una sedimentación calcárea posterior. Si la sedimentación es continuadamente calcárea. R. goyi puede persistir hasta el techo de la Zona Aalensis. Entre los Terebratúlidos, las especies reconocidas del género Stroudihyris, S. infraoolithica, S. stephanoides y S. písolithica se reemplazan a lo largo del intervalo considerado. La sustitución es gradual y es difícil precisar el momento en que ocurre. No obstante, en la transformación S. stephanoides, S. písolithica, hacia la parte media de la Zona Aalensis, los morfotipos correspondientes a la última de estas especies dominan en ambientes de sedimentación margosa y los que corresponden a la primera dominan en ambientes de sedimentación calcárea. Los Zeilléridos están poco representados en la cuenca durante este intervalo. Su distribución es relativamente homogénea. si bien tanto A. blakei como Z.(C.) anglica son más abundantes cuando la sedimentación es margosa. Los datos obtenidos permiten inferir que no se ha producido un cambio notable en las asociaciones de braquiópodos coincidiendo con el limite Toarciense-Aaleniense. Una renovación importante tiene lugar en la Zona Pseudoradiosa. Entre las Subzonas Aalensis y Buckmani se produce un cambio apreciable en las asociaciones y lo mismo ocurre entre las Subzonas Opalinum y Comptum.
Bioestratigrafía y paleontología (ammonitina) del Aaleniense en el sector noroccidental de la Cordillera Ibérica
(2016) Ureta Gil, María Soledad; Goy Goy, Antonio
Palaeoclimatic and biotic changes during the Aalenian (Middle Jurassic) at the southern Laurasian Seaway (Basque–Cantabrian Basin, northern Spain)
(Palaeogeography, palaeoclimatology, palaeoecology, 2009) Gómez Fernández, Juan José; Canales Fernández, María Luisa; Ureta Gil, María Soledad; Goy Goy, Antonio
The uppermost Toarcian–lowermost Bajocian deposits have been studied in 10 sections located in the western part of the Basque–Cantabrian Basin (northern Spain). The studied 276 successive recorded ammonite assemblages allowed detailed biostratigraphical subdivision and the correlation of the sections at the ammonite zone and subzone scale. The foraminifers were studied in 96 samples and 55 diagenetically screened belemnite rostra were analyzed for C and O isotope. Facies and thickness distribution of the Aalenian sediments suggest that deposition took place in a nearly symmetrical sub-basin included into an intraplate shallow platform, developed over continental crust, on which flexure was the main control responsible for subsidence and basin evolution. Noteworthy negative δ13Cbel excursions, coinciding with seawater temperature changes, were recorded during the Bradfordensis Biochron, around the Concavum–Limitatum biochron boundary, and around the Aalenian–Bajocian boundary. A close relationship between the changes in seawater temperature and the biotic changes observed in the foraminiferal and in the ammonoids assemblages has been evidenced. During the Comptum Biochron, the δ18Obel-based palaeotemperature shows a remarkable cooling interval with an average seawater temperature of 15.7 °C. This cooling favoured the immigration of species of foraminifers that thrived in platforms with colder seawater temperatures located north of the Basque–Cantabrian Basin. As a consequence, a strong increase in the diversity of the foraminiferal assemblages (28.5% of first appearances) occurred. This interval also coincides with the highest ammonoid abundance recorded during the Aalenian. A notable increase in temperature with peak values up to 24.3 °C, was measured during the Bradfordensis Biochron. This warming marks the beginning of progressive loss of foraminifer diversity and the decrease in the abundance of ammonoids. However, the increase in the relative abundances of some foraminiferal taxa such as the genus Spirillina during the warming phase is remarkable. Some of the foraminiferal species that had their last occurrence during this interval seem to be immigrants from NW Europe that arrived during the Comptum cooling interval, and that did not survive to rise of the seawater temperature. Another drop in temperature was recorded during the late Gigantea and the early Concavum biochrons. Coinciding with this cooling interval nearly 20% of the foraminiferal species disappeared while the ammonoid abundance increased. A new and significant warming episode occurred during the latest Aalenian (Limitatum Biochron), extending to the earliest Bajocian (Discites Biochron). Biotic response to this new ΔT of 2.5 °C is remarkable, marking one of the most important crises of the Aalenian. More than 30% of the foraminiferal species disappeared and no new appearances were recorded. Ammonoids show a decrease in the specimen abundance during the Limitatum–Discites warming, preceding a drastic decrease in the species abundance. The remarkable biotic changes linked to the variations of seawater temperature recorded in the Basque– Cantabrian Basin during the Aalenian, open the possibility that some of these faunal turnovers, specially marked in the benthic foraminifers, were of global extent and mainly forced by climate changes.
El tránsito Jurásico Inferior-Jurásico Medio en la sección de Fuentelsaz (Cordillera Ibérica): aspectos palinoestratigráficos
(I Congresso Ibérico de Paleontologia: XVI Jornadas de la Sociedad Española de Paleontología, 2000) Barrón, E.; Goy Goy, Antonio; Ureta Gil, María Soledad; Diez, J.B.; Balbino, A.C.