Person: Benito Moreno, María Isabel
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First Name
María Isabel
Last Name
Benito Moreno
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Geológicas
Department
Geodinámica, Estratigrafía y Paleontología
Area
Estratigrafía
Identifiers
8 results
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Item Strontium-isotope stratigraphy as a constraint on the age of condensed levels: examples from the Jurassic of the Subbetic Zone (southern Spain).(Sedimentology, 2008) Nieto, Luis M.; Ruiz-Ortiz, Pedro A.; Rey, Javier; Benito Moreno, María IsabelCondensed levels are often characterized by reworked fossils that may lead to incorrect age assessments. Strontium-isotope stratigraphy is an important chronostratigraphic tool that can be used to verify the biostratigraphic information from condensed beds. This paper describes a study of the 87Sr/86Sr isotope ratios of 56 belemnite samples collected from 28 stratigraphic sections of the boundary between the Upper Member of the Gavila´n Formation and the Zegrı´ Formation (Pliensbachian, Subbetic Zone). The petrographic and geochemical data (d18O, d13C, concentrations of Fe, Mn and Mg, and the Sr/Mn ratio) suggest that the belemnites have preserved their original marine geochemical composition. After plotting the samples in diagrams of 87Sr/86Sr values against time according to their biostratigraphic age, four different groups (A, B, C and D) were obtained with respect to the reference curve. In groups A and B, the age deduced from the Sr-isotope ratio is in total or partial agreement, respectively, with the biostratigraphic age; therefore the 87Sr/86Sr ratio is a good method for the dating, correlation and assessment of biostratigraphic results. In groups C and D, the SIS age and the biostratigraphic age do not coincide. A graphic procedure is presented as a suitable methodology to constrain the age of the samples showing an SIS age that differs from the relative age deduced (by biostratigraphy or stratigraphic correlation) for the bed they were collected in. These situations are interpreted as being the result of reworking of the belemnites (group C) or ammonites (group D) that are included in condensed levels. These condensed levels formed during the maximum flooding event that led to the drowning of the Gavila´n carbonate platform. The methodology supplied in this paper represents a valuable tool in identifying reworking processes, improving correlation and constraining biochronostratigraphic results. The values of 87Sr/86Sr represent a new contribution to the data set of 87Sr/86Sr ratios for the Pliensbachian.Item Influencia del Keuper y de la estructuración tardivarisca en la arquitectura de las unidades sin-extensionales del borde norte de la Cuenca de Cameros(Geotemas, 2016) Suárez González, Pablo; Benito Moreno, María Isabel; Mas Mayoral, José Ramón; Quijada, Isabel Emma; Campos Soto, SoniaEste trabajo aporta nuevos datos cartográficos y sedimentológicos para aclarar la controvertida evolución tectónica extensional de la Cuenca de Cameros (N de España). La geometría actual del borde norte de la cuenca representa la continuación de lineaciones tardivariscas NO-SE y SO-NE reconocidas en la Cuenca Vasco-Cantábrica, a lo largo de las cuales se produjo una importante tectónica salina sin-extensional. En la zona de estudio, la distribución irregular de los depósitos plásticos del Keuper es interpretada aquí como debida a una movilización sin-extensional. De este modo, la estructuración tardivarisca del basamento y las movilizaciones de Keuper, asociadas a ella, permiten explicar la arquitectura y distribución de las unidades sin-extensionales del relleno de la cuenca.Item La ruptura de la plataforma carbonatada del Lías Inferior en el Subbético Oriental (Provincias de Murcia y Alicante): Distribución de facies y valores isotópicos del 87Sr/86S r , C y O(Geotemas, 2004) Nieto, Luis M.; Ruiz-Ortiz, Pedro A.; Rey, Javier; Benito Moreno, María IsabelThe carbonate rocks of the upper part of the Gavilán Fm from the Eastern Subbetic are studied. They have been dated as Early Pliensbachian (carixian) in age and they were deposited in a carbonate platform. The stratigraphic and facies analysis show that the general scheme proposed by Ruiz-Ortiz et al. (2004) for the middle and upper member of the formation, each of them interpreted as a depositional sequence, can be easily applied. Moreover, a third sequence can be differentiated from the unusual record of upper Carixian sediments in some of the studied sections. The evolution of the content in b,3C, b180 and 87Sr/86Sr, is also analyzed from belemnites rostra. The values of these isotope ratios range between their characteristic values for the Pliensbachian according to different authors. Some critical variations can be correlated with those proposed for equivalent ages by other authors.Item Registro de una transgresión marina en torno al tránsito Jurásico-Cretácico al oeste de la sub-cuenca de Penyagolosa (Teruel)(Geotemas, 2016) Campos Soto, Sonia; Caus Gracia, Esmeralda; Bucur, I.I.; Benito Moreno, María Isabel; Suárez González, Pablo; Quijada, Isabel Emma; Fernández, L; Mas Mayoral, José RamónLa Fm. Villar del Arzobispo es una unidad mixta siliciclástico-carbonática que es considerada como la unidad que representa la culminación de la tendencia regresiva del Jurásico terminal-Cretácico basal en la parte suroriental de la Cuenca Ibérica. En el oeste de la sub-cuenca de Penyagolosa (Cuenca del Maestrazgo) esta unidad está formada, en su parte inferior, por una alternancia de carbonatos marinos, areniscas y lutitas y, en la parte media y superior, por lutitas y areniscas, principalmente, que alternan con calizas que se van haciendo progresivamente más abundantes hacia el techo de la unidad. Estas calizas son peloidales, bioclásticas y oolíticas y contienen abundantes fósiles marinos. La presencia de estas facies marinas demuestra la existencia de un periodo transgresivo durante la sedimentación de la parte superior de la unidad. El estudio micropaleontológico ha revelado la presencia de una asociación de foraminíferos dominada por Anchispirocyclina lusitanica y del alga dasycladal Zergabriella embergeri, que indican que el episodio transgresivo tuvo lugar durante el intervalo Titoniense superior-¿Berriasiense inferior?Item Mineralogía del tránsito Pérmico-Triásico en sedimentos continentales del SE de la cordillera Ibérica: implicaciones paleoambientales(Macla, 2004) Fernández Barrenechea, José María; Rodas González, Magdalena; Benito Moreno, María Isabel; López Fraguas, Francisco Javier; Alonso Azcárate, J.; Arche Miralles, Alfredo; Horra Del Barco, Raúl De LaItem On the microstructure, growth pattern and original porosity of belemnite rostra: insights from calcitic Jurassic belemnites(Journal of Iberian Geology, 2016) Benito Moreno, María Isabel; Reolid, Matias; Viedma Molero, CristóbalCalcitic belemnite rostra are usually employed to perform paleoenvironmental studies based on geochemical data. However, several questions, such as their original porosity and microstructure, remain open, despite they are essential to make accurate interpretations based on geochemical analyses. This paper revisits and enlightens some of these questions. Petrographic data demonstrate that calcite crystals of the rostrum solidum of belemnites grow from spherulites that successively develop along the apical line, resulting in a “regular spherulithic prismatic” microstructure. Radially arranged calcite crystals emerge and diverge from the spherulites: towards the apex, crystals grow until a new spherulite is formed; towards the external walls of the rostrum, the crystals become progressively bigger and prismatic. Adjacent crystals slightly vary in their c-axis orientation, resulting in undulose extinction. Concentric growth layering develops at different scales and is superimposed and traversed by a radial pattern, which results in the micro-fibrous texture that is observed in the calcite crystals in the rostra. Petrographic data demonstrate that single calcite crystals in the rostra have a composite nature, which strongly suggests that the belemnite rostra were originally porous. Single crystals consistently comprise two distinct zones or sectors in optical continuity: 1) the inner zone is fluorescent, has relatively low optical relief under transmitted light (TL) microscopy, a dark-grey color under backscatter electron microscopy (BSEM), a commonly triangular shape, a “patchy” appearance and relatively high Mg and Na contents; 2) the outer sector is non-fluorescent, has relatively high optical relief under TL, a light-grey color under BSEM and low Mg and Na contents. The inner and fluorescent sectors are interpreted to have formed first as a product of biologically controlled mineralization during belemnite skeletal growth and the non-fluorescent outer sectors as overgrowths of the former, filling the intra- and inter-crystalline porosity. This question has important implications for making paleoenvironmental and/or paleoclimatic interpretations based on geochemical analyses of belemnite rostra. Finally, the petrographic features of composite calcite crystals in the rostra also suggest the non-classical crystallization of belemnite rostra, as previously suggested by other authors. © 2016, Universidad Complutense de Madrid. All rights reserved.Item New ichnites from the Middle Triassic of the Iberian Ranges (Spain): paleoenvironmental and paleogeographical implications(Historical Biology, 2010) Ganda, Georges; Horra Del Barco, Raúl De La; Galán-Abellán, Belén; López Gómez, José; Fernández Barrenechea, José María; Arche, Alfredo; Benito Moreno, María IsabelThe Iberian Basin or its present-day expression, the Iberian Ranges, was refilled with red bed sediments of alluvial origin during the late Olenekian–Anisian period represented by the Cañizar (Olenekian–Anisian) and Eslida (Anisian) Formations, both commonly known as Buntsandstein facies. In the late part of the Anisian, the Tethys Sea reached the eastern side of the Iberian microplate, represented by the shallow marine facies of the Landete and Cañete Formations, also called Muschelkalk facies. The ichnites studied in this paper belong to the Anisian continental-marine transition in the SE Iberian Ranges. The Cañizar Formation shows the oldest Triassic footprints found in the Iberian Peninsula, consisting in swimming, uncomplete lacertoid three digit Rhynchosauroides traces with possibly resting (cubichnia) and furrowing (pascichnia) Cruziana/Rusophycus due to large triopsids. Specimens from Lacertoïd and Crocodiloïd groups have been collected in the Eslida Formation. Rhynchosauroides sp. is the most representative ichnospecies of the first group, while in the Crocodiloïd group, the presence of Chirotherium barthii Kaup 1835 and Isochirotherium cf coureli (Demathieu 1970) are distinctive. In the Landete Formation specimens are found from Crocodiloïd and Dinosauroïd groups. Brachychirotherium gallicum Willruth 1917, Brachychirotherium sp. and Chirotherium sp. are characteristic of the first one, and ‘Coelurosaurichnus’ perriauxi and cf Paratrisauropus latus as the most representative of the second group. Some of the specimens described here present ancestors in the Early Triassic and have been described in the Triassic of North America, Italy and France. Possible paleogeographical connections with faunas of SE France can be inferred. Based on different sedimentary structures and plant remains, the footprints are related to fluvial systems within huge flood plains, playa and shallow marine environments, with alternating dry and wet periods. The vertical ichnites distribution during the Anisian shows that the fauna modification was weak at a high clade level. In the Triassic of the Iberian microplate, there are no findings of traces prior to the Anisian, and the footprint content for the Middle Triassic is less diversified than in other neighbouring regions. By comparison with other western Pangea areas, there was a later appearance of the forms after the end-Permian mass extinction event in the studied areaItem Jurassic Coastal Park: A great diversity of palaeoenvironments for the dinosaurs of the Villar del Arzobispo Formation (Teruel, eastern Spain)(Palaeogeography, Palaeoclimatology, Palaeoecology, 2017) Campos Soto, Sonia; Cobos, Alberto; Caus, Esmeralda; Benito Moreno, María Isabel; Fernández Labrador, Laura; Suárez González, Pablo; Quijada, I. Emma; Mas Mayoral, José Ramón; Royo Torres, Rafael; Alcalá, AlcaláThe Villar del Arzobispo Formation, cropping out in the western Peñagolosa sub-basin (Late Jurassic, eastern Spain), includes abundant dinosaur tracksites and bones, which occur in diverse mixed siliciclastic and carbonate facies deposited from shallow marine to coastal and alluvial paleoenvironments. The lower part of the unit, mainly composed of bioclastic and oolitic limestone, was deposited in an inner carbonate platform, which underwent episodic subaerial exposure and siliciclastic inputs from the emergent areas, and includes scarce dinosaur tracks. This environment evolved into a siliciclastic coastal and alluvial plain that was crossed by channels and affected by periodic flooding events, producing the deposition of splay lobes. Upward, the siliciclastic coastal and alluvial deposits are interbedded with inter- to supratidal limestone beds. These tidal and coastal deposits show the highest abundance, diversity and best preservation of dinosaur tracks and bones of the unit. This setting gradually evolved upward into an inner carbonate platform, producing the deposition of shallow marine bioclastic and oolitic limestone, which includes very scarce dinosaur tracks. The highest abundance, diversity and best preservation of theropod, sauropod, thyreophoran and ornithopod tracks occur at the top of tidal carbonate beds. Tracks also occur in the siliciclastic coastal and alluvial plain deposits, especially in the flood plain deposits, preserved, mainly, as infillings or natural casts. Additionally, very scarce and poorly-preserved tracks occur at the top of shallow marine carbonate beds. Bones may be rticulated and/or associated in the flood plain deposits, whereas they are isolated and dispersed in the splay lobe deposits. Although this unit has been previously assigned to the Tithonian-Berriasian, the analysis of larger benthic foraminifera suggests a Kimmeridgian-Tithonian age for the Villar del Arzobispo Formation. This is consistent with the dinosaur assemblages present in the unit, which are strongly related to other European Late Jurassic faunas.