Person:
Díaz Molina, Margarita

First Name

Margarita

Last Name

Díaz Molina

URI

https://hdl.handle.net/20.500.14352/82944

Affiliation

Universidad Complutense de Madrid

Faculty / Institute

Ciencias Geológicas

Area

Estratigrafía

Identifiers

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Now showing 1 - 10 of 17

El Trías de Alcázar de San Juan (Región de La Mancha).
(Cuadernos de geología ibérica, 1977) Yébenes, A.; Marfil, Rafaela; Soriano, J.; Peña, José Andrés de la; Díaz Molina, Margarita
Se ha levantado una columna litoestratigráfica de detalle entre Alcázar de San Juan y Campo dc Criptana, distinguiéndose seis unidades que en conjunto pasan de tener neto carácter detrítico en la base a facies evaporíticas en el techo. La potencia total es de 140 a 180 metros. Se definen los caracteres petrológicos y sedimentológicos, comparándose sus facies con los materiales triásicos de la Cordillera Ibérica y de la zona prebética.
Chert in bioturbated sediments of Sabkha paleoenvironment
(Abstracts: Flint production and exchange in the Iberian Southeast, III Millennium B.C : VI International Flint Symposium, post-symposium field trip, OCtober 5th-10th,1991, Granada-Almería / by A. Ramos Millán ... [et al.], 2001) Arribas Mocoroa, José; Bustillo Revuelta, María Ángeles; Díaz Molina, Margarita; Bustillo Revuelta, María Ángeles; Ramos Millán, A.
Efectos de la separación de flujo en las secuencias de barras de meandro. Ejemplos del Oligoceno Superior de la Cuenca de Loranca
(Geotemas, 2008) Muñoz García, María Belén; Díaz Molina, Margarita
El registro estratigráfico del Eoceno-Mioceno de la cuenca de Loranca está formado por sedimentos fluviales, aluviales y lacustres. Durante el Oligoceno Superior los depósitos de ríos meandriformes del abanico fluvial de Tórtola se extendieron por el centro de la cuenca y su margen oeste. Las barras de meandro del abanico de Tórtola presentan diferencias con el modelo de facies básico, en el que la secuencia de estructuras sedimentarias está producida por una disminución de la velocidad de la corriente. Las secuencias fining-upwards graduales no son las más frecuentes en las barras de meandro del Oligoceno de la cuenca de Loranca. La estructura sedimentaria más abundante es la estratificación cruzada de pequeña escala rellenando surcos erosivos, que puede presentarse en toda la sección de la barra de meandro. La estratificación cruzada de ripples compone a su vez otras formas del lecho que se caracterizan por una morfología de crestas longitudinales. Estas formas compuestas se interpretan como formas del lecho generadas por vórtices espirales en zonas de separación de flujo.
Petrological and mineralogical characterization of lutitic deposits in a fluvial dominated depositional system. Upper Oligocene - Lower Miocene, Loranca Basin (Central Spain)
(Revista de la Sociedad Geológica de España, 1995) Arribas Mocoroa, María Eugenia; Doval, Mercedes; Díaz Molina, Margarita
The study of the clay minerals in the Upper Unit (Upper Oligocene - Lower Miocene) in Loranca Basin shows a change from the bottom (subunit 1) to the top (subunit 2). Subunit 1 is characterized by the clay mineral association 1, when the great part of the clay minerals are detrital as illite and kaolinite. Subunit 2 is characterized by the clay mineral associations 2 and 3 which contain palygorskite. The great abundance in palygorskite along subunit 2 is related with a gradual diminution in the smectite content and with an important climate change. Clay mineral evolution reflects paleoenvironmental changes induced by tectonics and climate. Clay composition types cannot be associated to a clasification of flood-plain palaeoenvironments. [RESUMEN]: El estudio de los minerales de la arcilla en la Unidad Superior (Oligoceno superior-Mioceno inferior) de la Cuenca de Loranca muestra un cambio desde la subunidad 1 a la subunidad 2. La subunidad 1 se caracteriza por la presencia de una asociacion de minerales de la arcilla (asociacion 1), donde la mayor parte de los minerales de la arcilla son de origen detritico, como illita y caolinita. La subunidad 2 se caracteriza por las asociaciones 2 y 3 con paligorskita. La presencia de paligorskita a 10 largo de la subunidad 2 se relaciona con una disminucion gradual en el contenido de esmectita y con un importante cambio climatico. La evolucion de los minerales de la arcilla reflejan cambios paleoambientales inducidos por la tectonica y el clima. Los tipos composicionales de minerales de la arcilla no parecen estar asociados a los distintos paleoambientes dentro de la llanura fluvial.a clasification of flood-plain palaeoenvironments.
Geological modelling of a reservoir analogue: Cenozoic meander belts, Loranca Basin, Spain
(Petroleum geoscience, 1995) Díaz Molina, Margarita; Arribas Mocoroa, José; Gómez Fernández, Juan José; Tortosa, A.
The reconstruction of meander belts was approached by detailed geological mapping, the interpretation of exposed sandstone bodies and the application of sedimentological concepts. The single reconstructed meander belts were integrated, considering stratigraphic position and thickness in a threedimensional model of the depositional architecture. Some useful reservoir parameters, such as volume of meander loops, areas of interconnection and fluid flow barriers, are calculated from the obtained model. Sandstone porosity is mainly of primary origin and mechanical compaction is the most iotense diagenetic feature. Models of estimated permeability evolution in the point bar sequences have been developed. Gamma ray readiogs from different lithologies were obtained and grouped accordiog to their palaeoenvitonmental classification. The results are comparable to well logs and aid subenvitonmental characterization of continental deposits.
Ichnofauna from coastal meandering channel systems (Upper Cretaceous Tremp Formation, South-Central Pyrenees, Spain): delineating the fluvial-tidal transition
(Journal of paleontology, 2016) Díez Canseco, Davinia; Buatois, Luis A.; Mángano, M. Gabriela; Díaz Molina, Margarita; Benito Moreno, María Isabel
The Upper Cretaceous “redbeds” of the lower Tremp Formation (South-Central Pyrenees, Spain) contains an ichnofauna consisting of Taenidium barretti, Taenidium bowni, Loloichnus isp., Arenicolites isp., Planolites isp., and Palaeophycus isp. This ichnofauna occurs in deposits formed in tide-influenced meander loops and their associated overbank mudflats. Evaluation of the taphonomic controls on the Tremp ichnofauna shows that (1) two morphotypes of Taenidium barretti are controlled by the substrate consistence, (2) Arenicolites may be enlarged by erosion processes, and (3) Taenidium barretti and Planolites isp. are not the same ichnotaxa showing different types of preservation. The meniscate fill in Taenidium barretti suggests that this structure was produced by deposit feeders. The Tremp ichnofauna is grouped into two trace-fossil assemblages, a depauperate subaquatic monospecific Planolites suite and an assemblage representing the Scoyenia Ichnofacies.Trace-fossil distribution reflects paleoenvironmental changes in the meandering channels along the stratigraphic section with the Planolites suite in the lowermost part of the lower interval and the Scoyenia Ichnofacies in the middle and upper intervals. The lowermost suite may be likely formed seaward of the maximum salinity limit, under extreme brackish-water conditions, whereas the Scoyenia Ichnofacies records a freshwater assemblage that was formed landward of the maximum salinity limit, reflecting deltaic progradation.
Geological modelling of ancient meander belts as potencial hydrocarbon reservoirs, Loranca Basin, Central Spain (F-17)
(Technical programe and abstracts papers: (oral and poster presentations) : 4th Conference and Technical Exhibition, Paris, France, 1-5 June 19922 / European Association of Petroleum Geoscientists & Engineers, 1992) Díaz Molina, Margarita; Arribas Mocoroa, José; Gómez Fernández, Juan José
Silex "tobaceos" en el Mioceno inferior continental (provincia de Cuenca). Un ejemplo de silicificaciones de paleosuelos en ambiente de lago-playa
(Boletín de la Real Sociedad Española de Historia Natural. Sección Geológica, 1980) Bustillo Revuelta, María Ángeles; Díaz Molina, Margarita
Los sílex con estructura tobáceas aparecen con relativa frecuencia en el Terciario continental que aflora al E. de la sierra de Altomira. Alcanzan un gran desarrollo al techo de la "unidad detrítica superior" entre las poblaciones de Huete y Garcinarro. Estos sílex tobáceos se originan por reemplazamiento de yesos que poseen una estructura "tubular". La estructura, "tubular" se caracteriza por la disposición concéntrica de los cristales de yeso alrededor del eje vertical y se interpreta como rizocreciones .El aspecto petrográfico más importante de estos sílex es la presencia de esporas y la existencia de corpúsculos formados por materia orgánica y sílice. Se deduce que en el comienzo de la silicificación, las sustancias orgánicas originadas por la actividad vegetal son incorporadas a las disoluciones silíceas, se forman puntos de sobresaturación y precipitan los corpúsculos silíceo-orgánicos. La substitución se da en paleosuelos relacionados con un ambiente de lago-playa.
Dinosaur nests at the sea shore
(Nature -London, 2002) Sanz , J.L.; Moratalla, J.J.; Díaz Molina, Margarita; López Martínez, Nieves; Kälin, Otto; Vianey-Liaud, M.
Depositional setting and early diagenesis of the dinosaur eggshell-bearing Aren Fm at Bastus, Late Campanian, south-central Pyrenees
(Sedimentary geology, 2007) Díaz Molina, Margarita; Kälin, Otto; Benito Moreno, María Isabel; López Martínez, Nieves; Vicens, Enric
The Late Cretaceous Aren Fm exposed north of Bastus in the Tremp Basin (south-central Pyrenees) preserves an excellent record of dinosaur eggs laid in a marine littoral setting. Different from other cases reported in literature, at the Bastus site the preferential nesting ground was original beach sand. The coastal deposits of Aren Fm can be grouped into four facies assemblages, representing respectively shoreface, beachface, beach ridge plain and backbarrier lagoon environments. Shoreface deposits include fine- to coarsegrained hybrid arenites and subordinate quartz-dominated conglomerates with ripple structures of wave and wave-current origin. Beachface deposits are mainly storm beach conglomerates, but parallel-laminated foreshore arenites locally occur. Backbarrier lagoon deposits comprise of washover sandy conglomerates that grade laterally into sandy lime mudstones, biomicrites and marls. Beach ridge sediment, wherein the bulk of dinosaur eggs and eggshell debris occurs, predominantly is a reddish hybrid arenite that has undergone a complex early diagenetic evolution, including marine and meteoric cementation followed by soil development. The reddish arenites overlie wave-dominated shoreface deposits and in places pass laterally into lagoonal deposits. They originally formed shore ridges, that became stabilized during progradational episodes by pedogenesis (beach ridge, sensu[Otvos, E.G., 2000. Beach ridges—definitions and significance. Geomorphology 32, 83–108.]), which also affected the dinosaur eggs. The eggshell-bearing beach ridge arenites are typically preserved at the top of parasequences forming the systems tracts of a third-order sequence. Thick packages of this facies resulted from aggradation of barrier/beach ridge deposits, whose preservation below surfaces of transgressive erosion was favoured by incipient lithification.