Person: Arribas Mocoroa, María Eugenia
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First Name
María Eugenia
Last Name
Arribas Mocoroa
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Geológicas
Department
Mineralogía y Petrología
Area
Petrología y Geoquímica
Identifiers
54 results
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Item Interpreting carbonate particles in modern continental sands: an example from fluvial sands (Iberian Range, Spain)(Geological Society of America. Special Paper, 2007) Arribas Mocoroa, José; Arribas Mocoroa, María EugeniaWe analyzed modern fluvial sands in the Iberian Range in order to obtain an accurate description of the different typologies of carbonate grains and to interpret their origin. Head streams of the Iberian Range mainly receive carbonate sediments as (1) fragments from ancient carbonate rocks, and (2) penecontemporaneous car bonate grains generated in the fluvial channels or in associated subenvironments. The erosion of proximal carbonate sources (Jurassic and Cretaceous in age) contributes to the generation of carbonate rock fragments. In addition, erosion of recent freshwater tufas, carbonate soils, and other recent carbonates produces an important volume of penecontemporaneous carbonate particles. Temperate to subhu mid climate and short transport conditions promote good preservation of the composition and textures of carbonate grains in modern fluvial sands. Detailed petrographic analyses on penecon temporaneous carbonates provide diagnostic clues of their origin. Four main petro graphic classes of penecontemporaneous grains have been established: (1) penecon temporaneous micritic grains, which are composed of microcrystalline calcite with a filamentous or laminated microfabric, are derived from erosion of recent freshwa ter carbonate tufas. Penecontemporaneous micritic grains with alveolar microfabric are derived from recent carbonate soils. (2) Penecontemporaneous sparitic grains, which are composed of single crystals or of mosaics with filamentous microfabric, are the result of erosion of carbonate tufas. Other penecontemporaneous sparitic grains include Microcodium and speleothems fragments. (3) Penecontemporaneous coated grains, which are composed of a nucleus plus a coating of penecontemporane ous carbonate, represent bioinduced carbonate particles (cyanoliths) that originate in streams. (4) Penecontemporaneous bioclasts, made from charophytes, ostracods, and mollusks, are rare. ldentification of these grain categories in ancient deposits has implications for coeval carbonate supplies during fluvial sedimentation.Item Gypsum resources of Spain: Temporal and spatial distribution(Ore geology reviews, 2012) Escavy Fernández, José Ignacio; Herrero Fernández, María Josefa; Arribas Mocoroa, María EugeniaSpain is one of the main gypsum producers in the world. Spanish gypsum reserves are large and a good knowledge of the location of the ore reserves permits to establish better exploitation strategies. Plotting the Spanish major gypsum outcrops, using a GIS base, helps to classify them by age, establish the main depositional character and determine the factors controlling their origin. Evaporitic deposits from Cambrian to Quaternary are preserved throughout Spain. The evaporites are formed by chemical precipitation of natural brines, either of marine or continental origin. The oldest evaporite vestiges in the Spanish geological record have been described in carbonate materials, as gypsum and anhydrite pseudomorphs, in Cambrian deposits of the Cantabro–Iberian basin (northern Spain). The first properly identified evaporite formation in Spain is located in the Triassic deposits that characterize central and northern Europe. In Spain, evaporites of this age appear well represented in 4394.5 km2 of outcrop area in the eastern part of the Iberian Peninsula. The Lower Jurassic (covering 1068 km2 of outcrop area) and the Cretaceous (covering 706.9 km2 of outcrop area) are periods of intense evaporitic sedimentation, and outcrops appear concentrated towards central and eastern parts of the Peninsula. More recently, in the Cenozoic, numerous continental and marine basins resulted from the tectonic activity produced by the Alpine Orogeny. Here, a combination of different factors produced thick and wide evaporite accumulations (outcrop surface is 13592.7 km2). In the Quaternary, evaporitic conditions are common in Spain, including various saline lakes (covering 1092.1 km2 of outcrop area) mainly in the Ebro basin and La Mancha zone. In addition, there are many artificial marine salinas. The evaporitic conditions in a basin strongly depend on factors such as climate, tectonics and brine composition. A study of the spatial distribution and age of the gypsum-bearing units in Spain suggests a wide variation in factors controlling the origin of gypsum deposits. The Spanish evaporite precipitation from Permian to Jurassic times was controlled by global conditions such as climate. They were formed during a global warming period. On the other hand, evaporites formed from late Cretaceous to Neogene were more influenced by regional factors that were related to the tectonic activity produced by the Alpine Orogeny. At present evaporite precipitation occurs due to the endorheic character of lakes in some parts of Spain.Item Significance of geochemical signatures on provenance in intracratonic rift basins: Examples from the Iberian plate(Geological Society of America Special Paper, 2007) Ochoa, M.; Arribas Mocoroa, José; Arribas Mocoroa, María Eugenia; Mas Mayoral, José RamónFollowing the Variscan orogeny, the Iberian plate was affected by an extensional tec-tonic regime from Late Permian to Late Cretaceous time. In the central part of the plate, NW-SE–trending rift basins were created. Two rifting cycles can be identified during the extensional stage: (1) a Late Permian to Hettangian cycle, and (2) a latest Jurassic to Early Cretaceous cycle. During these cycles, thick clastic continental sequences were deposited in grabens and half grabens. In both cycles, sandstone petrofacies from periods of high tectonic activity reveal a main plutoniclastic (quartzofeldspathic) character due to the erosion of coarse-grained crystalline rocks from the Hesperian Massif, during Buntsand-stein (mean Qm72F25Lt3) sedimentation and during Barremian–early Albian times (mean Qm81F18Lt1). Geochemical data show that weatheringwas more intense during the second rifting phase (mean chemical index of alteration [CIA]: 80) due to more severe climate conditions (humid) than during the arst rifting phase (mean CIA: 68) (arid climate). Ratios between major and trace elements agree with a main provenance from pas-sive-margins settings in terms of the felsic nature of the crust. However, anomalies in trace elements have been detected in some Lower Cretaceous samples, suggesting additional basic supplies from the north area of the basin. These anomalies consist of (1) low contents in Hf, Th, and U; (2) high contents in Sc, Co, and Zr; and (3) anomalous ratios in Th/Y, La/Tb, Ta/Y, and Ni/V. Basic supplies could be related to the alkaline volcanism during Norian-Hettangian and Aalenian-Bajocian times. Geochemical composition of rift deposits has been shown to be a useful and complementary tool to petrographic deduction in prov-enance, especially in intensely weathered sediments. However, diagenetic processes and hydrothermalism may affect the original detrital deposits, producing changes in geochemi-cal composition that mislead provenance and weathering deductions.Item Análisis sedimentológico de los materiales lacustres (formación de Gorafe-Huélago) del sector central de la Depresión de Guadix(Estudios Geológicos, 1988) Arribas Mocoroa, María Eugenia; Fernández Martínez, Juan; García Aguilar, J.M.El análisis sedimentológico y petrológico de los materiales carbonatados de la formación de Gorafe Huélago (Plioceno), ha permitido diferenciar diversas facies que caracterizan varios subambientes de sedimentación carbonatada dentro de un sistema deposicionai tluvio-lacustre: llanura lutítica (limos, limos carbonatados y arenas), zonas de encharcamiento palustre (margas carbonosas), orla palustre carbonatada (calizas bioturbadas por raíces, calizas nodulosas y paleosuelos, costras calcáreas y margas nodulosas) y zona lacustre (calizas algales laminadas y oncolíticas, calizas fosilíferas, calizas margosas y margas). La evolución y distribución de las facies están controladas por el accidente tectónico del Negratin, fundamentalmente transcurrente y que atraviesa la zona de estudio con una dirección NE-SW. En el bloque levantado (sector N) tiene lugar una sedimentación carbonatada lacustre, mientras que en el bloque hundido (sector S) la sedimentación es fundamentalmente terrígena. Los materiales carbonatados que caracterizan la sedimentación lacustre se relacionan entre sí y con otras facies terrígenas en determinadas secuencias sedimentológicas lacustres: secuencias de retracción, secuencias de expansión y secuencias de expansión-retracción.Item Sandstone petrofacies in the northwestern sector of the Iberian Basin(Journal of iberian geology, 2007) Arribas Mocoroa, José; Ochoa, M.; Mas Mayoral, José Ramón; Arribas Mocoroa, María Eugenia; González Acebrón, LauraDuring the most active rifting stages in the northwestern sector of the Iberian Basin (Cameros Basin and Aragonese Branch of the Iberian Range), thick sequences of continental clastic deposits were generated. Sandstone records from Rift cycle 1 (Permo-Triassic) and Rift cycle 2 (Late Jurassic-Early Cretaceous) show similarities in composition. Based on the most recent data, this paper describes sandstone petrofacies developed during both rifting periods. Six petrofacies can be distinguished: two associated with Rift cycle 1 (PT-1 and PT-2) and four with Rift cycle 2 (JC-1 to JC-4). All six petrofacies can be classifi ed as sedimentoclastic or plutoniclastic. Sedimentoclastic petrofacies developed during early rifting stages either through the recycling of pre-rift sediments or signifi - cant palaeogeographical changes. These facies comprise a thin succession (<100 m) of clastic deposits with mature quartzose and quartzolithic sandstones containing sedimentary and metasedimentary rock fragments. Carbonate diagenesis is more common than clay mineral diagenesis. Sedimentoclastic petrofacies have been identifi ed in Rift cycle 1 (Saxonian facies, PT-1) and Rift cycle 2 (JC-1 and JC-3; Tithonian and Valanginian, respectively). In the absence of the pre-rift sedimentary cover, metasedimentoclastic petrofacies sometimes develop as a product of the erosion of the low- to medium-grade metamorphic substratum (Petrofacies JC-2, Tithonian-Berriasian). Plutoniclastic petrofacies were generated during periods of high tectonic activity and accompanied by substantial denudation and the erosion of plutonites. Forming thick stratigraphic successions (1000 to 4000 m), these feldspar-rich petrofacies show a rigid framework and clay mineral diagenesis. In Rift cycle 1, plutoniclastic petrofacies (PT-2) are associated with the Buntsandstein. This type of petrofacies also developed in Rift cycle 2 in the Cameros Basin (JC-4) from DS-5 to DS-8 (Hauterivian-Early Albian), and represents the main basin fi ll interval. Sedimentoclastic and plutoniclastic petrofacies can be grouped into three pairs of basic petrofacies. Each pair represents a ‘provenance cycle’ that records a complete clastic cycle within a rifting period. Petrofacies PT-1 and PT-2 represent the ‘provenance cycle’ during Rift-1. In the Cameros Basin, two provenance cycles may be discerned during Rift cycle 2, related both to the Tithonian-Berriasian and the Valanginian-Early Albian megasequences. Tectonics is the main factor controlling petrofacies. Other factors (e.g., maturation during transport, local supply) may modulate the compositional signatures of the petrofacies yet their main character persists and even outlines the hierarchy of the main bounding surfaces between depositional sequences in the intracontinental Iberian Rift Basin.Item Evolution of an intra-plate rift basin: the Latest Jurassic-Early Cretaceous Cameros Basin (Northwest Iberian Ranges, North Spain)(Geo-guías, Post-Meeting Field trips 28th IAS Meeting, Zaragoza, 2011) Mas Mayoral, José Ramón; Benito Moreno, María Isabel; Arribas Mocoroa, José; Alonso Millán, Ángela; Arribas Mocoroa, María Eugenia; Lohmann, K.C.; González Acebrón, Laura; Hernán, J.; Quijada, Isabel Emma; Suárez González, Pablo; Omodeo Salé, S.; Arenas, Concha; Pomar, Luis; Colombo, FerránItem 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, MargaritaThe 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.Item Petrographic characterization of coeval carbonate grains in recent fluvial sands (Serranía de Cuenca, Spain)(Plinius (Milano), 2002) Arribas Mocoroa, María Eugenia; Tortosa, A.; Arribas Mocoroa, JoséItem Petrología y análisis secuencial de los carbonatos lacustres de paleógeno del sector N de la Cuenca Terciaria del Tajo (provincia de Guadalajara)(Estudios Geológicos, 1986) Arribas Mocoroa, María EugeniaEn el NW de la Cuenca Terciaria del Tajo existe una potente sucesión carbonático-detrítica de edad paleógena que presenta una gran diversidad de facies carbonáticas. A partir del estudio detallado de 12 secciones estratigráficas (ARRIBAS, 1985), dichas facies han sido agrupadas en dos familias litológicas, carbonatos consolidados y carbonatos no consolidados. Dentro del grupo de carbonatos consolidados se han diferenciado: calizas homogéneas (calizas fosilíferas, calizas intraclásticas, calizas laminadas y calizas dolomíticas-dolomías) y calizas alteradas (calizas nodulosas, calizas nodulosas con terrígenos, calizas bioturbadas, calizas con estructuras prismáticas verticales, calizas oquerosas y calizas con laminación deformada y porosidad fenestral). A su vez, se han distinguido cuatro facies petrológicas dentro de los carbonatos no consolidados: margas, margas dolomíticas, «chalks» y «chalks» dolomíticos. En general, las calizas homogéneas son interpretadas como sedimentadas en ambientes lacustres de mayor o menor profundidad y las calizas alteradas como el resultado de una pedogénesis, tanto en las orlas palustres de los sistemas lacustres, como en las áreas de encharcamientos dentro de los sistemas aluviales asociados. Las facies carbonáticas se relacionan entre sí en determinadas asociaciones de facies litológicas y, en ocasiones, van asociadas a facies detríticas también en determinadas asociaciones de facies litológicas. El análisis secuencial vertical de las asociaciones de facies permite establecer unas pautas en la evolución de la sedimentación a lo largo de la sucesión carbonático-detrítica paleógena, desde ambientes de sedimentación lacustres y palustres a lo largo de la mitad inferior de la sucesión, hacía ambientes de sedimentación de abanicos aluviales en la mitad superior de ésta, debido a una progradación general de los sistemas de abanicos aluviales.Item Coeval carbonate grains in modern fluvial sands (Iberian Range, Spain): The activity of a Continental carbonate factory(Sedimentology at the dawn of the third millennium : Abstracts : 15th International Sedimentological Congress [held at the University of Alicante] April 12-17, 1998 [International Association of Sedimentologists (IAS)], 1998) Arribas Mocoroa, María Eugenia; Tortosa, A.; Cañaveras, J.C.; García del Cura, M. Ángeles; Soria, Jesús