Person: Arribas Mocoroa, José
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First Name
José
Last Name
Arribas Mocoroa
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Geológicas
Department
Mineralogía y Petrología
Area
Petrología y Geoquímica
Identifiers
14 results
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Item Evolution of sandstone composititon in a continental foreland basin. Loranca Basin, Spain.(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) Tortosa, A.; Arribas Mocoroa, José; Cañaveras, J.C.; García del Cura, M. Ángeles; Soria, JesúsItem Caracterización clastométrica de los depósitos detríticos de cabecera de arroyos en el Sistema Central: influencia de la litología del área fuente(Boletín de la Real Sociedad Española de Historia Natural. Sección geológica, 1990) Palomares Herranz, Marta; Tortosa, A.; Arribas Mocoroa, JoséSe caracterizan texturalmente los depósitos detríticos actuales generados en las zonas de cabecera de arroyos que drenan macizos constituidos por una única litología (granítica, gnéisica o pizarroso-esquistosa) en el Sistema Central. Dicha caracterización se basa en el análisis de las distribuciones clastométricas realizadas a partir de intervalos de tamaños de grano comprendidos entre 5,65 mm y 0,062 mm. Las distribuciones se caracterizan por presentar una o varias poblaciones, siendo la población transportada por saltación la más importante cuantitativamente. Las poblaciones transportadas por tracción y suspensión solamente están presentes en algunas muestras. Se han podido establecer los límites que separan cada una de las poblaciones, así las poblaciones de tamaños de grano inferiores a 0,27 mm han sido transportadas en suspensión y las de tamaños superiores a 1,5 mm lo han hecho por tracción. Por otra parte mediante los parámetros estadísticos de Md, So y Sk (mediana, selección y asimetría, respectivamente) es posible diferenciar entre depósitos de origen granítico, gnéisico y pizarroso-esquistoso. Los sedimentos de origen granítico poseen una mediana de 1,49 mm, selección «moderada» (So 1,63) y asimetría, en general, hacia tamaños gruesos (Sk = 0,92). Los depósitos de origen gnéisico poseen una mediana baja (Md 1,3 mm), selección «pobre» (So = 2, 23) Y asimetría hacia tamaños finos (Sk = 1,1); mientras que los depósitos de origen pizarroso-esquistoso poseen una mediana alta (Md = 4,47 mm), selección «muy pobre» (So = 2,45) Y asimetría hacia tamaños gruesos (Sk 0,98). Como conclusiones, cabe destacar que aparte de los factores que clásicamente se han venido considerando como determinantes de la morfología de las distribuciones clastométricas de los depósitos detríticos (medio de transporte y sedimentación), la litología del área fuente incide directamente en dicha morfología en sedimentos generados bajo condiciones de corto periodo de transporte y alta energía del mismo. De este modo, se abre una nueva vía de estudio para la caracterización litológica del área fuente en depósitos antiguos originados bajo condiciones similares a los analizados en el trabajo. [ABSTRACT] In this work we have analized the textural properties of modern detritaI deposits colected on head stream of the Central System (Spain). The source areas are single lithology (granitic, gneissic or sI ateschistic). The textural analysis is based on cumulative curves of grain size distributions between 5.65 mm and 0.062 mm. These distributions are composed by one or several populations. The main population is transported by saltation, while suspension and traction are represented only in sorne samples. We bear in mind that grain with size less than 0.27 mm are included in suspension population. Traction population is constituted by grains of more than 1,5 mm in size. On the other hand, the analysis of statistical parameters (median, sorting and skewness) permits us to discrimine between granitic, gneis sic and slate-schistic source deposits. The granitic so urce sediments have Md = 1.49 mm, «moderate» sorting (So = 1.63 mm) and skewness towards coarse sizes (Sk = 0.92). The gneissic source deposits have Md = 1.3 mm, «poor» sorting (So = 2.23) and skewness towards fine sizes (Sk = 1.1); however the slate-schistic source deposits have high median (Md = 4.47 mm), «very poor» sorting (So = 2.45) and skewness towars coarse sizes (Sk = 0.98). We conclude that the source area lithology falIs most heavily on morphology of grain size distributions than sedlmentary environments, in deposits generated on head streams (high energy and Iimited transport). Thus a new way of anaIyzing data concernig the lithological characterization of source area in old deposits originated in these environments, is open.Item 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.Item Petrographic evidence of different provenance in two alluvial fan systems (Palaeogene of the northern Tajo Basin, Spain)(Special publication - Geological Society of London, 1991) Arribas Mocoroa, José; Arribas Mocoroa, María EugeniaPalaeogene detrital deposits of the northern Tajo Basin are coalescent alluvial fan systems interfingering distally with lacustrine carbonates. Non-carbonate extrabasinal clasts increase to the east while carbonate extrabasinal clasts decrease. Rock fragments increase to the west, while the feldspar/quartz ratio remains constant. Rock fragments define two sedimentary domains: the Iberian, in the east, was derived from Mesozoic rocks of the Iberian Range, and the Central System, to the west, was derived from Cretaceous cover and Palaeozoic metamorphic basement. Evolution of sandstone composition is related to erosion of the source areas and is different in the two domains. The tectonic setting is apparently "recycled orogen", providing calcareous rock fragments are included in the total lithic clasts.Item 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 JoséItem Factors controlling compaction in a fluvial sequence: Oligocene-early Miocene of Lorance Basin, Central Spain(17th Regional African European Meeting of Sedimentology : abstracts, March 26th-28th 1996 / IAS, International Association of Sedimentologists...[et al.], 1996) Arribas Mocoroa, José; Arribas Mocoroa, María Eugenia; Tortosa, A.Item Análisis petrológico de depósitos de terrazas aplicado al estudio de los procesos de captura en los ríos Adaja, Voltoya y Eresma (provincias de Segovia y Valladolid)(Revista de la Sociedad Geológica de España, 1997) Tortosa, A.; Arribas Mocoroa, José; Garzón Heydt, Guillermina; Fernández García, Paloma; Palomares Herranz, MartaLa caracterización composicionaI y textural de los depósitos arenosos de terrazas de los ríos Adaja, Voltoya y Duero ha permitido resolver la procedencia de otras secuencias de terrazas, relacionadas con estos ríos pero hasta ahora de difícil asignación genética, como son las situadas al SE de Pozáldez y en el área de Olmedo. La secuencia de terrazas del área de Pozáldez se ha dividido en dos grupos: el primero, correspondiente a las terrazas más antiguas, está relacionado con el retrabajamiento de las terrazas del Duero por el río Voltoya durante su encajamiento. El segundo grupo, formado por las terrazas más modernas, se relaciona con los depósitos del río Adaja, marcando el límite de ambos grupos el momento de la captura de este último por el Voltoya. Por otra parte, la secuencia de terrazas del área de Olmedo refleja una gran similitud con las arenas del sistema del Voltoya, pudiendo ser considerado como parte del mismo. La integración de los datos geomorfológicos y petrológicos ha permitido elaborar un modelo de evolución de la red fluvial basado en capturas sucesivas entre los ríos Adaja, Voltoya y Eresma. [ABSTRACT] The analysis of the composition and texlures of the sandy deposits of terraces of Adaja, Voltoya and Duero rivers permits to solve the provenance of other terrace sequences, as those appearing at the SE of Pozáldez and near Olmedo, without a clear parentage with the rivers mentioned aboye. TheAdaja terraces are constituted by arkoses with crystalline rock fragments and a light dominance of k-feIdspar over plagioclase grains, representing the more immature deposits analysed. The Voltoya terraces al so consist of arkoses with a greater dominance of k-feldspar over plagioclase and with the occurrence of metamorphic rock fragments. The Duero terraces are formed of subarkoses with low content in rock fragments, showing a great dispersion of the contents in feldspars and rock fragments typologies. Based on these data, the upper terraces appearing near Pozáldez are constituted by the reworking product of Duero terraces by lhe Volloya river during the incision of its channel. The lower terraces are constituted by recent terraces whose origin is related to the Adaja river. Thus the limit between these two groups of terraces represents the capture of the Adaja by the Voltoya river. On the other hand, the terrace sequence near Olmedo shows a great similarity with the deposits of the VoItoya terraces, so that its origin is related to this terrace system. The integration of geomorphologic and petrologic data permits lhe reconstruction of the evolution of the fluvial network, based on successive channel piracy. Firslly, lhe Adaja river was captured by the Voltoya river, and subsequently both the Adaja and Voltoya rivers were captured by the Eresma river. The origin of this set of captures is the general trend to the NE of the groundwater flow, caused by tectonic tilting, and improving the hydraulic efficiency of the basin. Finally, the composition of the terrace deposits was greatly influenced by the piracy processes that produced a new input of sediments with different provenance. Incision of lhe channels also affected composition by reworking of intrabasinal sediments. Both processes acted by mixing sediments producing a homogenisation of its composition. As a consequence, an important loose of detailed information about the source area of the different feeders occurs.Item Detrital modes in sedimentoclastic sands from first-order streams of the Iberian Range, Spain: the effect of source lithology(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, José; Peña, José Andrés de la; Tortosa, A.; Cañaveras, J.C.; García del Cura, M. Ángeles; Soria, JesúsItem Modern stream sands from compound crystalline sources: Coniposition and sand generation index(Geological Society of America, Processes controlling the composition of clastic sediments, 1993) Palomares Herranz, Marta; Arribas Mocoroa, JoséCompositions of modern first-cycle sands derived from granitic and metamorphic terrains in the Spanish Central System have been analyzed in order to evaluate the contributions of different bedrock types. The results of this work indicate that sand composition normally does not permit quantitative statements concerning sourceland composition. This is due to the fact that each rock type has a different potential to generate sand, dependent on such properties as its mineralogy, average crystal size, and microfabric. We introduce the concept of sand generation index (SGI), which is a relative measure of the capacity of one bedrock type to generate sand with respect to another in a compound source area. SGI of granitoid is 14 to 20 times greater than SGI of slate-schist when these rock types appear in a dual crystalline source. In the case of a gneiss + slate-schist source rock association, the SGI of gneiss is about five times greater than the SGI of slate-schist, whereas the SGI of gneiss is similar to that of granitoid in case of a dual granitoid + gneiss source. Finally, our results show that quantitative estimates of source land composition based on QFR diagrams are hazardous if the concept of the SGI is disregarded.Item Grain size, composition, porosity and permeability contrasts within cross-bedded sandstones in Tertiary fluvial deposits, central Spain(Sedimentology, 1993) Hartkamp, Christel A.; Arribas Mocoroa, José; Tortosa, A.Permeability measured with a portable probe pcrmcflmeter on outcrops of cross·bcdded sandstones ranges betwecn 0·9 and 19 O. The highest pcrmeability (2-19 0 with an avcrage of8·5 D) occurs in thc coarsest grained foresct laminae (CFL). intermediate values (2-120 with an average of 5·3 D) occur in fincr grained foreset laminac (FFL) and thc lowest values (0·9-1 0 0 with un avcrage of 4·8 D) occur in boltomsct laycrs (BL). In the cross·bcds the uverage grain sizc rangcs from medium graincd sand in the CFL to finc grained s,lnd in thc FFL and BL. In all three subf'lcies. the average size of the primary pores is approximately It/> unit smaller than the averagc grain size. The abundance of unstablc carbonatc clasts correlatcs with incrcasing avcrage grain size, micritic clasts being most abundant in the CFL. Converscly. quartz content incrcascs with decreasing grain size and is highest in the FFL and BL. Oiagenetic destruction of primary porosity by compact ion and cementation. as well �IS generation of sccondary porosity through dissolution, were controlled by the original mineralogical composition of the sand. Contrasts in grain size detcrmine the primary pore size contrasts and differences in composition bctwecn CFL. FFL and BL. Permeability contrasts reflect variations in averagc primary pore size rather than differenccs in total porosity. Probe permeability contrasts between eFL. FFL and BL depend on contrasts in llverage pore size and contrasts in mineralogical composition between the subfacies.