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
3 results
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Item Clayey materials from the Sierra de la Demanda Range (Spain): their potential as raw materials for the building ceramics industry(Clay minerals, 2005) Artigas, Rosana; Rodas, Magdalena; Sánchez Jiménez, Carlos J.; Mas Mayoral, José Ramón; Dondi, Michele; Arribas Mocoroa, JoséThis work describes the possible use of thick Early Cretaceous clay deposits, which occur in the southern sector of the Sierra de la Demanda range, as raw materials in the manufacture of ceramic articles. The global mineralogical composition is characterized by high proportions of phyllosilicates and quartz with variable quantities of feldspars, carbonates and hematite. The clay mineralogy differentiates two types of raw materials: illitic clay and kaolinitic-illitic clay. A granulometric distribution in the 2ÿ60 mm fraction, good behaviour during the drying stage and acceptable results in firing tests confirmed that most samples can be utilized as raw material in the building ceramics industry. The range of suitable firing temperatures for these materials is 950ÿ1000ëC, a temperature which needs to be raised for samples with a high percentage of kaolinite and quartz. Moreover, other materials with abundant calcite (20ÿ30%) are suitable for use as modifiers of some properties or colour.Item Detrital modes in sedimenticlastic sands from low-order streams in the Iberian Range, Spain: the potential for sand generation by different sedimentary rocks(Sedimentary Geology, 2003) Arribas Mocoroa, José; Tortosa, A.The composition of modern stream sands derived from sedimentary source rocks in the Iberian Range has been analyzed in order to evaluate the contributions of the different bedrock types (mainly sandstones, limestones and dolostones). Temperate to subhumid climate and short transport conditions promote a weathering-limited denudation regime. As expected, sand composition proved to be essentially quartzolithic, with variable amounts of penecontemporaneous carbonates. Sand compositional data were compared with the exposure areas of the different bedrocks in the drainage sub-basins considered for semi-quantitative assessment of the sand generation potential of each bedrock type. Siliciclastic formations (sandstones) appear to be by far the most significant sand producers, with Sand Generation Indices (SGIs) in the medium sand fraction ranging from 4 to 20; i.e., 4 to 20 times greater than the SGI of carbonate rocks. Composition and texture are the main factors controlling carbonate sand generation. Sparitic limestones yield higher SGIs (2.8 to 20) when source terrains are constituted exclusively by carbonate rocks. High sparite grain content in the sands is enhanced by supplies from additional sources, such as calcitized dolostones. Dolomicrite sources are strongly under-represented in the sands analyzed (very low SGI), whereas the proportion of micritic limestone grains tends to be an accurate reflection of that bedrock at the source. Even though the results presented here refer to the first stage of sand generation with negligible transport effects, we think they may be helpful in the analysis and reconstruction of source terrains in ancient sedimenticlastic depositsItem Criteria for recognition of localization and timing of multiple events of hydrothermal alteration in sandstones illustrated by petrographic, fluid inclusion, and isotopic analysis of the Tera Group, Northern Spain(International journal of earth sciences, 2011) González Acebrón, Laura; Goldstein, Robert H.; Mas Mayoral, José Ramón; Arribas Mocoroa, JoséStratigraphic relations, detailed petrography, microthermometry of fluid inclusions, and fine-scale isotopic analysis of diagenetic phases indicate a complex thermal history in Tithonian fluvial sandstones and lacustrine limestones of the Tera Group (North Spain). Two different thermal events have been recognized and characterized, which are likely associated with hydrothermal events that affected the Cameros Basin during the mid- Cretaceous and the Eocene. Multiple stages of quartz cementation were identified using scanning electron microscope cathodoluminescence on sandstones and fracture fills. Primary fluid inclusions reveal homogenization temperatures (Th) from 195 to 350 C in the quartz cements of extensional fracture fillings. The high variability of Th data in each particular fluid inclusion assemblage is related to natural reequilibration of the fluid inclusions, probably due to Cretaceous hydrothermal metamorphism. Some secondary fluid inclusion assemblages show very consistent data (Th = 281–305 C) and are considered not to have reequilibrated. They are likely related to an Eocene hydrothermal event or to a retrograde stage of the Cretaceous hydrothermalism. This approach shows how multiple thermal events can be discriminated. A very steep thermal gradient of 97–214 C/km can be deduced from d18O values of ferroan calcites (d18O -14.2/-11.8% V-PDB) that postdate quartz cements in fracture fillings. Furthermore, illite crystallinity data (anchizone–epizone boundary) are out of equilibrium with high fluid inclusion Th. These observations are consistent with heat-flux related to shortlived events of hydrothermal alteration focused by permeability contrasts, rather than to regional heat-flux associated with dynamo-thermal metamorphism. These results illustrate how thermal data from fracture systems can yield thermal histories markedly different from hostrock values, a finding indicative of hydrothermal fluid flow.