Geogaceta -- Nº 14, (1993)

Permanent URI for this collectionhttps://hdl.handle.net/10272/13960

Browse

Now showing 1 - 20 of 47

Análisis secuencial de la Formación Arenas de Utrillas en el N. de la provincia de Cuenca (Cordillera Ibérica)
(Sociedad Geológica de España, 1993) Ruiz, G.; Segura, M.
Six depositional sequences have been recognized in the Cretaceous terrigenous facies of the Iberian Ranges in the studied area. The Ist and 2nd sequences show caracteristics of continental environments, the 3rd and 4th sequences have caracteristics not well defined, probably transitionnal environments, and the 5th and 6th show caracteristics of coastal environments. The proposed age is Hauterivian-Barremian for the Ist, Aptian for the 2nd,upper Albian for 3rd and 4th, and Iower Cenomanian for 5th and 6th sequences
El Albense-Cenomanense del Pto. del Remolcador (Cordillera Ibérica, Maestrat, Castelló): secuencias deposicionales y biozonación con grandes foraminíferos
(Sociedad Geológica de España, 1993) Schröeder, R.; García, A.; Cherchi, A.; Segura, M.
Preliminary results of micropa/eontological and sequential studies of the thickest and most marine A/bian-Cenomanian series in the Iberian Ranges are presented. Numerous larger foraminifera indicate Late Albian, Vraconian as well as Early and Middle Cenomanian age. Based on the platform model elaborated by García et al. (1993), the sequentia/ ana/ysis of the section allows the identification of the U.Z.A- 1.5, U.Z.A-2.1, U.Z.A-2.2 and U.Z.A-2.3 sequences ofHaq etal. (1988). New and more precise data on the distribution oftheMid-Cretaceous large foraminifera in eastern Spain are obtained
Correlación litoestratigráfica de las evaporitas messinienses en las cuencas de Lorca y Fortuna (Murcia)
(Sociedad Geológica de España, 1993) Ortí, Federico; García Veigas, Javier; Rosell, L.; Rouchy, J. M.; Inglés, M.; Gimeno, Domingo; Playà, Elisabet; Kasprzyk, A.
The Messinian evaporite formations of Lorca and Fortuna basins may be linked along the exposures developed in the Guadelentín depression. Accordingly, the La Serrata Gypsum unit of the Lorca basin correlates with the "lower evaporite init" of the Fortuna basin
Un borde de plataforma Urgoniana al NE de la provincia de Alicante (zona Prebética)
(Sociedad Geológica de España, 1993) Castro Jiménez, José Manuel
During late Barre mian-early Aptian times, the development of a carbonate platform took place, with deposit of rudistid and corallim estones in NW of Alicante province (SE of Spain). In the Benidoleig-Jalón area, a detailed stratigraphic study has pointed out that there is a transition between the carbonate platform domain and the open basin to the South. The transitional sections are made up ofhemipelagic deposits, In which there are several levels of interbeded bioclastic limestones with no much lateral extension; these limestones have been interpreted as been redeposited from the external platform in relation to relative sea level changes.
Sobre la hidroquímica de la cuenca del río Almanzora (Almería)
(Sociedad Geológica de España, 1993) Castillo, A.; Vallejos, Ángela; Cerón García, Juan Carlos
The waters of the Almanzora basin have very different chemistry according to the hydrogeological context; the mineralization is between 0,4 and more than 6 g/i; the hydrochemical facies is usually . calcic, bicarbonated in the carbonated aquifers, of lower salinity, and sulphated for the detritic aquifers and surface waters. Mild regional thermal ism also occurs with emergence temperatures usually ranging between 20 and 28º C
Sedimentologia del sector occidental del abanico costerò de Sant Llorenf del Munt (Eoceno, cuenca de antepais surpirenaica)
(Sociedad Geológica de España, 1993) López Blanco, Miguel; Marzo, M.
The Bartonian-Priabonian Sant Lloreng del Munt fan-delta complex is located at the SE margin of the South-Pyrenean foreland basin. During the deposition of this complex the basin margin was controlled by a series of sinistral strike-slip faults that under transpressive conditions developed some thrusting structures. The fan-delta complex consists of an alternation ofdetrital and carbonate facies. The detrital facies (more than the 9 0 % in volume of the com plex) includ e the deposits of four main facies belts: proximal alluvial fan (conglomerates), distal alluvial fan and fan-delta plain (conglomerates and red sandstones and mudstones), fan-delta front (sandstones and conglomerates) and fan-delta slope (bluegrey offshore marls and "turbiditic" sandstones and conglomerates). The carbonate facies are mainly represented by bioclastic shoals and reefs
Relaciones entre la diagénesis orgánica y mineral en rocas madre de cuencas lacustres: cuenca terciaria de Ribesalbes
(Sociedad Geológica de España, 1993) Permanyer, Albert; Marfil Pérez, Rafaela; Dorronsoro Urrutia, C.
Lacustrine carbonate sediments from the Tertiary Basin of Ribesalbes (Castellón, Spain) were studied with the aim of determining the relationships between organic and mineral diagenesis. Petrological and geochemical data indicated that organic matter was inmature type I. Both mineralogy and textural relations suggest that Mg-rich blue-green algae contributed to the high Mg/Ca rate found in the Ca-MgFe carbonates through diagenetic process.ln the first stage of the diagenesis, in the lacustrine anoxic environment, the bacterial processes was dominant producing the precipitation of the Ca-Mg carbonates and aragonite.Because sulfate reduction was not significant, the Mg-calcite or dolomite and the aragonite were replaced by ankerite when fermentation started, with an important methane production of bacterial origin.The most remarkable characteristics of the porosity data and the poresize distribution curves are the moderate range of porosity values (10-26%) and the porosity parameters -sorting and skewness-, which are more affected by the early organic diagenetic processes than by mechanical compaction.
Rasgos generales del relieve en el sector suroriental de la Sierra Almijara (Málaga)
(Sociedad Geológica de España, 1993) Rodríguez Vidal, Joaquín; Cáceres Puro, Luis Miguel
The morphostructural landform o f this Betics coastal sector is conditioned by lithological, structural (Neotectonics) and geomorphologicai features. Tortonian planated relief was faulting during Mio-Pliocene age by a NW-SE oblique-slip and normal faults, like a stepped landscape, with a 700 m. of relative fall
Procesos de sedimentación ligados a flujos gravítacionales en regiones semiáridas. Un ejemplo del SE de España
(Sociedad Geológica de España, 1993) Martín Penela, A. J.; Barragán, G.
In the studied area the rainfalls ofautum 1973 and 1989 led to the development of gravity flows of mud and/or debris flow type and their characteristic sediments. The analysis of rain fall conditions, processes and deposits reveals that the genesis of sediment by gravity in these areas had a catastrophic and sporadic nature, and is controlled by the intensity and/or duration of rainfalls, the nature and thickness of the regolith in the slopes, the steepeness of these and development of the vegetal cover
Presencia de mineralogías ricas en Zn como evidencias de la actividad hidrotermal enzonas de cizalla extensionales (Complejo Nevado-Filábride, Béticas)
(Sociedad Geológica de España, 1993) Soto, Juan I.; Muñoz, Mercedes
Late Zn-rich assemblages have been found in several lithilogies of the Bédar-Macael unit and upper part of the Calar-Alto unit (Nevado-Filabride Complex). The nowadays brittle contacts between the nevado-filábride and alpujárride units are low-angle normal faults of an extensional system Middle Miocene in age. In metabasite rocks of the Bédar-Macael unit, Zn-rich staurolite (ZnO<13 wt%) partially transformed to gahnite-haematite+quartz assemblage has been found
Presencia de Cloritoide en las pizarras ordovícicas del sinforme de Alcañices (Zamora)
(Sociedad Geológica de España, 1993) Fernández Fernández, A.; Moro Benito, M. C.
In the present work we describe for the first time the presence of chloritoid associated with slates of Llanvirn-Llandellian age (Latedo Formation) o f the southern flank of the Alcahices Synform (Zamora). Usually this mineral metamorphic appears in islated prismatic crystals or forming aggregates that are radial, parallel or oblique to the SI and S3 schistosity of the slates. Analysis by electronic microprobe, EDAX and X-ray difraction (XRD) indicates that these chloritoids belong to the ferrous variety, with low MgO contents and without zoning or appreciable differences among the crystals and they mainly correspond to the triclinic polytype
Organización secuencial del sector occidental del abanico costero de Sant Llorenç del Munt (Eoceno, cuenca de antepaís surpirenaica)
(Sociedad Geológica de España, 1993) López Blanco, Miguel; Marzo, M.
The study of the relationships among facies belts in the Eocene Sant Llorenç d el Munt fan-delta complex allow sus to differentia te three orders of transgressive-regressive cyclicity . The basic building blocks are the "fundamental sequences". The study of the stacking pattern of these "fundamental sequences" lead us to the definition of "transgressive units ", "regressive units " and "composite sequences". A comparative analysis between these concepts and those currently used in sequence stratigraphy models is developed
Nuevos datos sobre comprensión pleistocena en el extremo oriental del Algarve (Portugal)
(Sociedad Geológica de España, 1993) Flores Hurtado, Enrique; Rodríguez Vidal, Joaquín; Cáceres Puro, Luis Miguel
The end of the Pliocene was characterized by a return to the compressive regime throughout the southern of the Iberian peninsula. Quaternary deformations are intense in places and correspond to folds and occasionally reversal faults. At the western sector of the Guadalquivir basin the neotectonic activity is not still investigated. The studied section shows folded Quaternary terrace deposits and sometimes crushed terraces between mesozolc rock bodies. The entire studied outcrop looks as a WSW-ENEAW-E fault zone that, also a possible previous activity, it would support strain, at least compressive, contemporary to the terrace deposits (Pleistocene).
Nota sobre las plantas fósiles del Mioceno de Epila (Zaragoza)
(Sociedad Geológica de España, 1993) Ferrer, Javier; Fernández Marrón, M. T.; Liñán Guijarro, Eladio
Fossil plants from Epila village (Zaragoza province) at the Ebro Depression are described. Osmunda parschlugiana, Sabalites and undetermined monocotyledoneous are found in travertinic limestone of a supposed Lower-Middle Miocene age. This discovery suggests the presence of a mainly terrestrial episode developped into a tropical or subtropical climate and within a generalized lacustrine sequence
Neoformación de fases minerales secundarias ricas en tierras raras en los granitos de la Sierra de Guadarrama: Bastnaesita-(CE)
(Sociedad Geológica de España, 1993) Casillas Fernández, R.; Nagy, G.; Brändle, José Luis; Panto, G.; Forizs, I.
The subsolidus postmagmatic alteration processes in the granites of the Sierra de Guadarrama produce the transformation and neoformation of the principal and accesory phases. One of these secondary minerals is the bastnaesite-(Ce) wich concentrates the rare earth originated by the allanite and monazite mineral destruction
Modelo genético de las secuencias arenosas de plataforma de la Formación Balmaseda (Albiense de la Cuenca Vascocantábrica, N de España)
(Sociedad Geológica de España, 1993) Pérez García, Adán; Robles, Sergio; Vicente Bravo, J. C.
A new palaeoenvironmental interpretation of the Middle Albian-Lower Cenomanian Balmaseda Formation, deposited in SW margin o f the Basque Cantabrian Basin (N Spain) is offered here. According to the facies association, sedimentary sequences and paleocurrents analysis of the unit in the Tornos Pass cross section (Vizcaya, Burgos and Cantabria provinces), the western part of the Balmaseda Fm. has been explained as a storm dominated siliciclastic shelf
Mineralogía de los sedimentos de la Laguna de Fuente de Piedra (provincia de Málaga)
(Sociedad Geológica de España, 1993) Rodríguez Jiménez, P.; Carrasco Cantos, Francisco; Benavente Herrera, José; Almécija Ruiz, Carmen
Sampling of sediments from the Fuente de Piedra playa lake (Málaga province, Spain) has been carried out both in the surface salt crust and in two shallow holes. The following minerals have been mainly indentified: quartz, feldspars, phyllosilicates, calcite, dolomite, gypsum, halite and hexahydrite. There seems to exist a lateral zonation with increasing salt contents towards the center ofthe Lake, as well as a vertical trend that is characterized for two processes: the carbonates dolomitization and the diagenetic growing of gypsum cristals
Middle Miocene extensional faulting events and Alpujarride Units in the Central Betics
(Sociedad Geológica de España, 1993) Azañón, José Miguel; Crespo Blanc, Ana; García Dueñas, V.; Orozco, Miguel
In the Central Betics, the Alpujarride Complex is made up of units which result from the dismembering of pre-Miocene fold nappes during a Late Burdigalian (?)-Langhian extensional event
Los piroxenos de las rocas graníticas de la Sierra de Guadarrama (S.C.E.)
(Sociedad Geológica de España, 1993) Casillas Fernández, R.
The pyroxenes are rarely observed in the granitic rocks from the Sierra de Guadarrama. The clinopyroxene only exists in the basic-intermediate types of cafemic calc-alkaline associations ( El Tiemblo, Almenara, Ventosilla, etc); in the granodiorites from alumino-cafemic monzonitic associations ( Navas del Marqués and La Cabrera ), or in the enclaves included in these rocks. Only in the Ventosilla pluton is also possible to find ortopyroxene crystals. The geochemical study of these phases allows the determination of different conditions of formation of these minerals: f02, Tª, etc, in the various granitic types. In some occasions and possibly by slow cooling rate of the plutonio masses, the crystals of clinopyroxene present granule exolution and subsolidus reequilibrium
Los Orbitolínidos de las Calizas de Aras de Alpuente (Albense superior) en la región de Requena (Cordillera Ibérica, Valencia)
(Sociedad Geológica de España, 1993) Bravo, C.; García Palacios, A.
The Orbitolinids are studied in five Upper Albian sections composed by neritic carbonates. Their sequential correlation allow the biostratigraphic characterization of the parasequences and the elaboration of a stratigraphic distribution chart of foraminifera. The two lower parasequences contain Simplorbitolina conulus. The 3rd and 4th parasequences present transitional morphologies between Simplorbitolina and Neorbitolinopsis. The 5th parasequence is characterized by Neorbitolinopsis conulus. The microfauna ofthe 6th, upper, parasequence is Dictyoconus casterasi, Orbitolina aperta and Orbitolina corbarica

Browse

Recent Submissions