Person: Mas Mayoral, José Ramón
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First Name
José Ramón
Last Name
Mas Mayoral
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Geológicas
Department
Area
Estratigrafía
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Item La Cuenca de Cameros: desde la extensión Finijurásica -Eocretácica a la inversión terciaria - implicaciones en la exploración de hidrocarburos.(Zubía. Monográfico, 2002) Mas Mayoral, José Ramón; Benito Moreno, María Isabel; Arribas Mocoroa, José; Serrano, Ana; Guimerà Rosso, Joan; Alonso Millán, Ángela; Alonso Azcárate, JacintoLa Cuenca de Cameros, localizada en la parte NO de la Cordillera Ibérica, es una de las cuencas que constituyen el Sistema de Rift Mesozoico Ibérico o Cuenca Ibérica. Se formó en el contexto de la segunda fase de rifting intraplaca que, desde el Jurásico superior al Albiense inferior, tuvo lugar cuando Iberia se separó de Europa en relación con la apertura de la cuenca oceánica del Golfo de Vizcaya. Al mismo tiempo se formaron varias cuencas a lo largo del surco Ibérico de orientación NO-SE, siendo la de Cameros la más occidental en el Sistema de Rift Mesozoico Ibérico. El relleno de la Cuenca de Cameros (Titónico-Albiense inferior) corresponde a un gran ciclo o super-secuencia que está limitado por dos importantes discordancias en la base y en el techo. La Supersecuencia o Megaciclo Jurásico terminal - Cretácico inferior se organiza en ocho secuencias deposicionales limitadas por discontinuidades estratigráficas, este registro sedimentario es de carácter esencialmente continental (sistemas aluviales y lacustres) con sólo muy esporádicas incursiones marinas. Hay varios hechos distintivos que la diferencian de las otras cuencas del Sistema de Rift Ibérico: (1) influencia marina muy escasa; (2) retardo ele los procesos de diastrofismo, pues el rifting empezó primero en la parte SE del surco ibérico (Kimmeridgiense en la Cuenca del Maestrazgo) y después se propagó hacia el NO (Titónico en la Cuenca de Cameros); (3) sin embargo, y a pesar de su poslclon interna, esta cuenca fue la más subsidente, registrando el mayor espesor de sedimentos, llegándose a acumular 5000 m de espesor vertical de sedimentos desde el Titónico hasta el Albiense inferior, que representan hasta 9000 m de registro estratigráfico en el sentido de desplazamiento de los depocentros de las sucesivas secuencias de depósito; (4) a pesar de su gran registro sedimentario, se trata de una cuenca sinclinal que, durante su formación, no estuvo limitada por grandes fallas; y (5) esta cuenca es la única entre las cuencas mesozoicas del Rift Ibérico, en la que sus depósitos se han visto afectados por metamorfismo. Se trata de un metamorfismo de bajo y muy bajo grado que, durante el Cretácico medio-superior, afectó a la parte oriental de la cuenca. Su génesis y evolución son explicadas mediante un modelo de cuenca de bloque de techo ( <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, 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 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 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 Multiphase quartz cementation in sandstones: Terra group (Tithonian, Cameros basin, NE Spain)(25rd IAS Meeting of Sedimentology : Grece, Patras, 4-7 September 2007, Meeting of Sedimentology. Book and abstracts, 2007) González Acebrón, Laura; Mas Mayoral, José Ramón; Arribas Mocoroa, José; Goldstein, Robert H.; Benito Moreno, María IsabelItem Sedimentary evolution and provenance of the Last Fluvial episodes of the Cameros Basin (Lower Cretaceous, North Spain)(Fluvial Sedimentology. Abstract: The 8th International Conference on Fluvial Sedimentology (8th ICFS) will be hosted by the Delft University of Technology during August 7-12, 2005., 2005) Najarro, María; Arribas Mocoroa, José; Mas Mayoral, José Ramón; Ochoa, M.Item Destruction of a fluvial reservoir by hydrothermal activity (Cameros Basin, Spain)(Sedimentary Geology, 2007) Ochoa, M.; Arribas Mocoroa, José; Mas Mayoral, José Ramón; Goldstein, Robert H.This study provides an example of a high-quality fluvial hydrocarbon reservoir that was completely destroyed by hydrothermal processes. The reservoir unit was deposited in the Cameros Basin, located in the NW sector of the Iberian Chain (Spain). The basin was filled with clastic fluvial deposits (sandstones and conglomerates) between Late Berriasian and Early Aptian times. Provenance of sands was mainly from coarse crystalline rocks. A humid tropical climate produced intense weathering of K-feldspar during transport from source to basin. Thus, a mineralogically mature rigid framework with high porosity existed at the time of deposition, which would have constituted a high-quality hydrocarbon reservoir. At present however, the porosity of the reservoir is negligible. Porosity was reduced by a sequence of diagenetic processes: (1) mechanical compaction (i.e. crushing of metamorphic lithic grains) and chemical compaction, (2) kaolinite and siderite cementation, and (3) early quartz cementation. Hydrocarbon emplacement probably occurred between phases (2) and (3). A low-grade metamorphic (hydrothermal) event, reaching greenschist facies, took place during the Late Cenomanian. It dramatically reduced the remaining porosity of the reservoir and destroyed the hydrocarbon charge. Hydrothermal processes which affected the sandstones include (1) re-compaction; (2) late quartz cementation and silicification of remaining feldspars; (3) carbonate cementation; (4) chloritization of feldspars, metamorphic lithic fragments and intrabasinal argillaceous grains; and (5) growth of pyrite and chloritoid crystals on argillaceous material of intrabasinal, extrabasinal or even diagenetic origin. Hydrocarbons that migrated to the margins of the basin escaped these hydrothermal modifications and were preserved. The results of this study may be used to predict the diagenetic and hydrothermal evolution of other potential reservoirs in similar tectonic settings.Item Composición y diagénesis del registro detrítico en el borde suroccidental de la Cuenca de Cameros.(Zubía. Monográfico, 2002) Arribas Mocoroa, José; Mas Mayoral, José Ramón; Ochoa, M.; Alonso Millán, ÁngelaMediante el estudio petrográfico de los depósitos arenosos pertenecientes a las secuencias deposicionales del relleno de la Cuenca de Cameros, en su margen suroccidental, se han podido definir cuatro petrofacies, que coinciden con las siete secuencias deposicionales establecidas, respetando su jerarquía y los límites de las dos mega secuencias mayores de edad Titónico-Berriasiense y ValanginienseAlbiense inferior, respectivamente. Cada megasecuencia se inicia con una petrofacies sedimentoclástica (petrofacies A y C), generada por la erosión de materiales pertenecientes a la cobertera mesozoica pre-rift. Ambas megasecuencias evolucionan a petrofacies cuarzofeldespáticas (petrofacies B y D), que se generan a partir de la erosión de rocas metamórficas de bajo y medio grado de la Zona Asturoccidental Leonesa del Macizo Hespérico para la primera megasecuencia, y de rocas granitico-gneíssicas de la Zona Centro Ibérica para la segunda megasecuencia. La variación en las áreas de procedencia se explica con la propagación de la fracturación hacia el SW durante la génesis de los surcos subsidentes. La diagénesis se encuentra, a su vez, controlada por la composición de las areniscas, observándose importantes cementos carbonáticos tempranos en las petrofacies A y C, que ocluyen la porosidad e inhiben la compactación, y valores importantes tanto de porosidad primaria como secundaria en la petrofacies D, debido a la rigidez del esqueleto cuarzofeldespático, la escasa cementación y a la disolución de feldespatos potásicos.Item Provenance of fluvial sandstones at the start of late Jurassic–Early Cretaceous rifting in the Cameros Basin (N. Spain)(Sedimentary Geology, 2007) González Acebrón, Laura; Arribas Mocoroa, José; Mas Mayoral, José RamónThe Cameros Basin (Iberian Chain, Central Spain) developed during the latest Jurassic–Early Cretaceous in an extensional regime characterized by high rates of subsidence. Its sedimentary fill has been subdivided into eight depositional sequences (DS) mainly composed of continental sediments. DS 1 and DS 2 represent the first rifting stage (Tera Group, Tithonian). The purpose of this study is to characterize the Tera Group in the eastern part of the basin based on provenance criteria derived from fluvial sandstones. In this area of the basin, the Tera Group can be subdivided into three formations: the Ágreda Formation, the Magaña Formation and the Sierra de Matute Formation. These formations are composed of alluvial-fan deposits, meandering fluvial sediments and lacustrine–palustrine mudstones. A quantitative petrographic study indicated the presence of three main petrofacies in the Tera Group. The close correlation between petrofacies and lithostratigraphic units indicates that sandstone composition is a powerful tool for deciphering the tectonic processes active during the initial rift stages of the Cameros Basin. Petrofacies 1 is sedimentolithic (mean: Qm54F3Lt43) and represents erosion of the Jurassic marine pre-rift substratum (mainly Kimmeridgian limestones) during deposition of theDS 1 alluvial fan deposits (Ágreda Fm.). Petrofacies 2 is quartzofeldspathic, and can be subdivided into Petrofacies 2A,with an average composition ofQm84F15Lt1 and Petrofacies 2B,whose average composition isQ71F23Lt6. Petrofacies 2 was generated by the erosion of low to medium-grade metamorphic terranes and plutonic source rocks. It characterizes the Magaña Fm. (DS 2). Petrofacies 3 is quartzolithic (mean: Qm67F16Lt17), and is attributed to tectonic reactivation of the basin. This petrofacies characterizes the Sierra deMatute Fm. (DS 2). Thus, the provenance evolution of this basin is characterized by erosion of the pre-rift sedimentary substratum, followed by unroofing of the basement, as recorded in other ancient and modern rifted basins.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.