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
94 results
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Now showing 1 - 10 of 94
Item Sandstone petrography of continental depositional sequences of an intraplate rift basin: western Cameros Basin (North Spain)(Journal of sedimentary research, 2009) Arribas Mocoroa, José; Alonso Millán, Ángela; Mas Mayoral, José Ramón; Tortosa, A.; Rodas González, Magdalena; Fernández Barrenechea, José María; Alonso Azcárate, Jacinto; Artigas, RosanaThe Cameros Basin in Central Spain is an intraplate rift basin that developed from Late Jurassic to Middle Albian time along NW–SE trending troughs. The sedimentary basin fill was deposited predominantly in continental environments and comprises several depositional sequences. These sequences consist of fluvial sandstones that commonly pass upward into lacustrine deposits at the top, producing considerable repetition of facies. This study focused on the western sector of the basin, where a total of seven depositional sequences (DS- 1 to DS-7) have been identified. The composition of sandstones permits the characterization of each sequence in terms of both clastic constituents and provenance. In addition, four main petrofacies are identified. Petrofacies A is quartzosedimentolithic (mean of Qm85F2Lt13) and records erosion of marine Jurassic pre-rift cover during deposition of fluvial deposits of DS-1 (Brezales Formation). Petrofacies B is quartzofeldspathic (mean of Qm81F14Lt5) with P/F > 1 at the base. This petrofacies was derived from the erosion of low- to medium-grade metamorphic terranes of the West Asturian–Leonese Zone of the Hesperian Massif during deposition of DS-2 (Jaramillo Formation) and DS-3 (Salcedal Formation). Quartzose sandstones characterize the top of DS-3 (mean of Qm92F4Lt4). Petrofacies C is quartzarenitic (mean of Qm95F3Lt2) with P/F > 1 and was produced by recycling of sedimentary cover (Triassic arkoses and carbonate rocks) in the SW part of the basin (DS-4, Pen˜ - acoba Formation). Finally, depositional sequences 5, 6, and 7 (Pinilla de los Moros–Hortigüela, Pantano, and Abejar–Castrillo de la Reina formations, respectively) contain petrofacies D. This petrofacies is quartzofeldspathic with P/F near zero and a very low concentration of metamorphic rock fragments (from Qm85F11Lt4 in Pantano Formation to Qm73F26Lt1 in Castrillo de la Reina Formation). Petrofacies D was generated by erosion of coarse crystalline plutonics located in the Central Iberian Zone of the Hesperian Massif. In addition to sandstone petrography, these provenance interpretations are supported by clay mineralogy of interbedded shales. Thus, shales related to petrofacies A and C have a variegated composition (illite, kaolinite, and randomly interlayered illite–smectite mixed-layer clays); the presence of chlorite characterizes interbedded shales from petrofacies B; and Illite and kaolinite are the dominant clays associated with petrofacies D. These petrofacies are consistent with the depositional sequences and their hierarchy. An early megacycle, consisting of petrofacies A and B (DS-1 to DS-3) was deposited during the initial stage of rifting, when troughs developed in the West Asturian–Leonese Zone. A second stage of rifting resulted in propagation of trough-bounding faults to the SW, involving the Central Iberian Zone as a source terrane and producing a second megacycle consisting of petrofacies C and D (DS-4, DS-5, DS-6, and DS-7). Sandstone composition has proven to be a powerful tool in basin analysis and related tectonic inferences on intraplate rift basins because of the close correlation that exists between depositional sequences and petrofacies.Item Provenance of Triassic Feldspathic Sandstones in the Iberian Range (Spain): significance of Quartz Types(Journal of Sedimentary Petrology, 1985) Arribas Mocoroa, José; Marfil Pérez, Rafaela; Peña, José Andrés de laThe base of the Triassic in the Iberian Range is represented by detrital sediments (Buntsandstein facies) deposited initially in a continental environment, finally evolving into a marine environment that is represented at the top of the sequence. The lithology of this facies is dominated by arkosic sandstones. The aim of this study is to reconstruct the nature and position of the source areas of these sandstones. Provenance research was carried out by quartz-grain typology. Eleven stratigraphic sections were sampled. The amount of interstitital matrix has been considered in selecting samples because mechanical compaction suffered by sandstones with little matrix may give rise to a significant increase in the undulosity of monocrystalline quartz. The 0110 de Sapo gneissic formation, located in the Hesperian Massif, has been mentioned as source rocks offeldspathic sandstones in previous works. In order to verify the provenance of feldspathic sandstones, in artificial sands derived by grinding gneisses, and sand samples collected at stream heads that drain the gneiss outcrops, we followed the methodology ofBasu et al. (1975). Analytical results indicate that two different areas within the Triassic basin were notably influenced by different source areas: a) a western zone, the nearest to the gneissic source rocks, where monocrystalline, nonunduIatory quartz grains predominate (Qm :s5"); and b) an eastern zone farther from the gneissic source area, where polycrystalline quartz grains (Qp) and undulatory, monocrystalline quartz grains (Qm > 5") increase. Sediment evolution during transport processes is markedly reflected by the increase in Qm :s 5°/(Qp + Qm > 5") ratios in the westernmost zone, away from the source area. Low values in the above-mentioned ratios in the eastern zone are interpreted as results oflocal influence by low-ranking metamorphic source areas. Finally, this method also allows for the monitoring of the evolution of sediment maturity throughout the basin.Item Cyclicity recorded in the provenance sandstones in the sedimentary infill of the Cameros basin (N. Spain)(Boletín geológico y minero, 2013) González Acebrón, Laura; Arribas Mocoroa, José; Omodeo-Salé, S.; Arribas Mocoroa, María Eugenia; Le Pera, E.; Mas Mayoral, José Ramón; López-Elorza, M.; Fernández-Díaz, P.R.The intraplate Cameros rift basin in the north of Spain was formed came into being between the Tithonian and the Early Albian and contains 9 000 m of mostly continental sediments. This basin is a good example of cyclicity of different depositional sequences (DSs) in sedimentary environments, which show clear repetition in their sandstone composition (petrofacies) and diagenetic patterns. The DSs are arranged in two megasequences (MSs) separated by a tectonic unconformity. A similar vertical sandstone compositional evolution, subdivided into two stages that repeat cyclically, has been recognised in both MSs: the first comprises quartzo-sedimentolithic petrofacies and the second is made up of several quartzo-feldspathic petrofacies. This was caused by a progression from the recycling of the pre-rift sedimentary cover to the erosion of the mainly plutonic and metamorphic crystalline basement. These changes in the erosion of the different source areas were conditioned by the tectonics of the basin. Furthermore, the original sandstone framework composition conditioned the diagenetic pattern of the two stages: quartzo-sedimentolithic sandstones containing large amounts of very pervasive carbonate cement that reduce their original porosity considerably, and quartzo-feldspathic petrofacies with a rigid framework that maintained the original pores during burial diagenesis. This compositional and diagenetic pattern is probably applicable to other non-volcanic rifted basins, depending upon the original amount of carbonate rock fragments present.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, Jesús- Project number: 292
Item Rutas geológicas virtuales como recurso educativo abierto (open access) en asignaturas de Geología Aplicada(2016) Herrero Fernández, María Josefa; Álvarez Sierra, María De Los Ángeles; Ureta Gil, María Soledad; Castiñeiras García, Pedro; Arribas Mocoroa, José; Escavy Fernández, José Ignacio; López Acevedo, Francisco Item 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.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, María Eugenia; Arribas Mocoroa, José; Mas Mayoral, José RamónFollowing the Variscan orogeny, the Iberian plate was affected by an extensional tectonic 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 Buntsandstein (mean Qm72F25Lt3) sedimentation and during Barremian–early Albian times (mean Qm81F18Lt1). Geochemical data show that weathering was more intense during the second rifting phase (mean chemical index of alteration [CIA]: 80) due to more severe climate conditions (humid) than during the first rifting phase (mean CIA: 68) (arid climate). Ratios between major and trace elements agree with a main provenance from passive-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 provenance, especially in intensely weathered sediments. However, diagenetic processes and hydrothermalism may affect the original detrital deposits, producing changes in geochemical composition that mislead provenance and weathering deductions.Item Interpretación de la procedencia mediante el estudio de la tipologia de los granos de cuarzo: aplicación a las areniscas del Buntsandstein de la Cordillera Ibérica.(Actas del IX Congreso Nacional de Sedimentología, 1986) Arribas Mocoroa, José; Marfil Pérez, Rafaela; Peña, José Andrés de laLa procedencia de las areniscas ha sido abordada en los últimos años mediante el estudio de la tipologia de los granos de cuarzo. Gracias a las metodologías propuestas por diversos autores. Se pretende con este trabajo analizar la validez de las mismas, habiendo seleccionado para ello la de BASU et al. (1975) por considerarla la más idónea. Los materiales utilizados para este "chequeo" han sido las areniscas del Buntsandstein de la Cordillera Ibérica. El desarrollo del método empleado ha permitido confirmar la naturaleza gneisica de las áreas fuentes asi como poner de relieve la evolución espacial de la madurez de las areniscas estudiadas. Finalmente, se valora positivamente el método de BASU et al. (1975) frente a otras técnicas clásicas (minerales pesados, feldespatos, etc.) para ser aplicado en ciertos casos a problemas de procedencia. [ABSTRACT] The provenance of sandstones has been approached through the study of the quartz grains tipologies according to the methods proposed by several authors. This paper tries to check up the validity of these methods. Basu's et al method has been chosen to study the sandstones of the Buntsandstein of the Iberian Range for considering it the most suitable. The method has verified the gneissic nature of the source area, as well as the spatial evolution of the maturity of the studied sandstones. Finally, Basu's method, applied on certain provenance problems, la considered better than clasical ones (heavy minerals, feldspars, etc).Item Influence of granitoid textural parameters on sediment composition: Implications for sediment generation(Sedimentary Geology, 2012) Caracciolo, Luca; Tolosana Delgado, Raimon; Le Pera, Emilia; Eynatten, Hilmar von; Arribas Mocoroa, José; Tarquini, SimoneThe aim of this study is to determine and characterise the control exerted by parent rock texture on sand composition as a function of grain size. The sands investigated were generated from granitoid parent rocks by the Rhone, Damma and Sidelen glaciers, which drain the Aar Massif in the Central Alps (Switzerland), and were deposited in glacial and fluvio-glacial settings. Mechanical erosion, comminution (crystal breakdown and abrasion) and hydraulic sorting are the most important processes controlling the generation of sediments in this environment, whereas chemical and/or biochemical weathering plays a negligible role. By using a GIS-based Microscopic Information System (MIS), five samples from the glacier-drained portions of the Aar basement have been analysed to determine textural parameters such as modal composition, crystal size distribution and mineral interfaces (types and lengths). Petrographic data of analysed sands include traditional point counts (Gazzi-Dickinson method, minimum of 300 points) as well as textural counts to determine interface types, frequency, and polycrystallinity in phaneritic rock fragments. According to Pettijohn's classification, grain‐size dependent compositions vary from feldspathic litharenite (0φ fraction) via lithic arkose (1φ and 2φ) to arkose (3φ and 4φ). Compositional differences among our data set were compared to modern plutoniclastic sands from the Iberian Massif (Spain) and the St. Gabriel Mts. (California, USA), which allowed us to assess the role exerted by glaciers in generating sediments. By combining data from the MIS with those from petrographic analysis, we outlined the evolution of mineral interfaces from the parent rocks to the sediments.Item 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.