Geogaceta -- Nº 36, (2004)

Permanent URI for this collectionhttps://hdl.handle.net/10272/8622

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Facies diagráficas en el subsuelo terciario de la provincia de León (Formación Mansilla)
(Sociedad Geológica de España, 2004) Herrero, A.
They are analized the electric logs of a several wells located in the region northwest of the Duero Basin. These wells cross the upper 700 m of the Candanedo Aloestratigraphic Unit (Mansilla Formation). In them are differentiated three principal electrofacies: river channel, flood plain and of progradational lobe. The electrosequential analysis shows the retrogradation of the distal facies on proximal facies in upper part of the unit
Valoración patrimonial de las formaciones dunares Cuaternarias del Barranco de los Encantados y Cantera de Melián de la isla de Fuerteventura (Islas Canarias)
(Sociedad Geológica de España, 2004) Yanes, Y.; Castillo, Carolina; Hutterer, R.; Nuez, J. de la; Torres, Trinidad de; Ortiz, José Eugenio; Torres, J. M.; Alonso, M. R.; Ibánez, M.; Quesada, M.
This paper deals with the evaluatioh of the preservation interest of two Quaternary loca lites with aeolian deposits, Barranco de los Encantados and Cantera Melián, from the Fuerteventura Island (Canary Islands). Their scientific, social and cultural importance has been evaluated. It is noteworthy to signify that thay are the type localities of a new terrestrial gastropod species belonging to genus Cochlicella. Due to mining activities are destroying both deposits, their inclusion in the maximum level of legal protection has been proposed (Paleontological Zone according to 4/7999 law on Canarian Historical Heritage)
Valoración patrimonial de los yacimientos de icnitas de dinosaurio de la provincia de Teruel
(Sociedad Geologica de España, 2004) Cobos, Alberto
Dinosaur tracks have always been very attractive for the general public. This effect can be used to promote tourism showing the different tracksites. To give them their real value as there are some previous requirements: First an appropriate scientific study, then adequate restoration and protection and later public diffusion and correct accessibility to the sites. In the province of Teruel there are 13 dinosaur tracksites ranging from the Upper Jurassic to the Upper Cretaceous
Sustituciones Se042 -S042' en el yeso: un estudio experimental
(Sociedad Geológica de España, 2004) Fernández González, M. A.; Andara, A.; Prieto, M.
Se/enaíe (SeOf) and sulfate (50/-) have similar structural and chemical properties, and they can play a similar geochemical role. The competition between both anions has been considered in different fields. We present experimental work on crystallisation of Ca(Se04,SC)J-2H20 solid solutions from aqueous solutions. A complete structural characterization of solid solutions by X-ray powder diffraction and thermocalorimetic analysis were carried out. The differences in structural parameters for the different solid compositions have allowed us to quantify the non-ideality of the solid solution and the calculation of a thermodynamic model of this solid solution-aqueous solution system. In addition, the work includes some observations on dehydration behaviour of CaSe0/2H20- CaS042H20 endmembers and solid solutions
Sismicidad y tectónica en el área de Becerreá - Triacastela (Lugo, NO España)
(Sociedad Geológica de España, 2004) López Fernández, Carlos; Pulgar, J. A.; Gallart, J.; González Cortina, J. M.; Díaz, J.; Ruiz, Mario
The most active seismic spot in the northwestern part of the Iberian Peninsula is located between Becerreá and Triacastela (Lugo). Since 1995 an apparent increase of the activity has taken place: several seismic events took place, which included twenty earthquakes of the magnitude > 4 and a main event of magnitude 5.3 (21 May 1997). Most recently, a permanent low-magnitude activity (5-10 events/month) is registered in this zone. Lack of suitable seismic information prevents any rigorous analysis of this activity and its origin. We undertook a detailed study of the local seismicity between 1999 and 2002, based on the deployment of a temporary seismic array (CASPI Project). The integration of the new seismic data and the geologic information has allowed to obtain an updated image of the seismicity of this zone and to identify the Becerreá fault like the main seismogenetic source
Sedimentologia e interpretación paieoambiental de los canales fluviales de la Formación Mansilla en el Mioceno de la provincia de León
(Sociedad Geológica de España, 2004) Herrero, A.
They are defined four sort of associations of fades that are interpreted as fluvial channel landfills: low sinuosity with gravel and sands load, high sinuosity with gravel and sands load. For each one of they are provided their characteristic sedimentologicas. It is analyzed fluvial channel deposit's and the tectonic control of the paleocurrents
Respuesta de los acuíferos en el área de Muía (Murcia, SE de España) a los movimientos sísmicos de 1999
(Sociedad Geológica de España, 2004) Martínez Parra, Marc; Durán Valsero, Juan José
In February 1 999lh an earthquake near the city of Mula (Murcia, SE Spain) happened with 4,8 magnitude. Later, occurred more earthquakes, the main of them in May, with 3,0 magnitude. In epicentral zone there are termal springs with special hydrochemical characteristics, related with the presence of important regional faults. This work discusses possible alterations of groundwater physico-chemical parameters caused by these earthquakes. Oscilations in concentrations have been observed, mainly in sulphate
Resistencia al rebote en materiales de la Formación Casaio (Ordovícico del NO de España)
(Sociedad Geológica de España, 2004) Rodríguez Sastre, M. A.; Gutiérrez Claverol, M.; Torres Alonso, M.; Rodríguez Bouzo, M.
Several types of Ordovician Rocks (Casaio Formation in Truchas Synclinal) have been tested with the Schmidt hammer, model L. The compressive strength of these rocks has been estimated by the rebound values "in situ" and "in rock blocks" as very different from low to very high in order to its weathering and cleavage position
Repartición de los Foraminíferos bentónicos recientes en la marisma Victoria (Noja, Cantabria)
(Sociedad Geológica de España, 2004) Pascual, Ana; Martín Rubio, Maite; Rodríguez Lázaro, Julio
Recent benthic Foraminifera from superficial sediments of the Victoria marsh (Noja, N. Spain) have been studied. A total of 45 species have been identified, 15 of which were alive during the sampling. Lobatula lobatula is the most abundant species of the assemblages. Secondary species, richness and diversity, as well as the preservation of carapaces allow us to define three areas in the marsh: littoral lagoon, dunes area and mouth of the beach. The occurrence of living specimens of L. lobatula in the inner lagoon evidences that the marine water reaches that part of the marsh, even the filling of the ria and the anticontamination barrier displayed due to the «disaster of the Prestige». The occurrence of estuarine species as Ammonia tepida, Cribroelphidium williamsoni, Haynesina germanica and Trochammina inflata testifies that, though scarce, benthic foraminifers are present in the marsh. The best preserved transitional environment in this area is that of the dunes, where the foraminifers characterise the vegetated marsh and high estuary environments. In the mouth of the beach, the foraminifer assemblage is that of the littoral milieu, with an increase of the porcellaneous tests and specially, of the species Quinqueloculina seminula
Relaciones estratigrafías y sintectónicas de los conglomerados miocenos de Montejo de la Vega (borde SE de la cuenca del Duero)
(Sociedad Geológica de España, 2004) Nozal, F.; Montes Santiago, M. J.
New precisions are given about the stratigraphy and chronology of the marginal conglomerate units and their associated distal fades in the SE sector of the Duero Basin are described. The syntectonic units formed during the latest episodes of Alpine uplift (Guadarrama stage) in Honrubia anticline located in the northern border fault of the Spanish Central System
¿Registro de un paleoincendio en el límite Plioceno-Pleistoceno de la cuenca de Guadix-Baza (Granada, España)?
(Sociedad Geológica de España, 2004) Ortiz, José Eugenio; Torres, Trinidad de; Valle Hernández, María; Badal, E.; Llamas, F. J.; Cortés, A.; Vela, A.
This paper deals with the organic geochemistry of a "lignite" bed at the bottom of the Guadix-Baza composite stratotype section, just below the end of the Olduvai Chron. The results of the organic matter analysis (low H/C ratio and predominance of even n-alkanes) together with the lack of pollen and micromammal remains as well as the abundance of charcoal particles, suggest the development of the first wild-fire in the Mediterranean realm, which affected the catchment area of the alluvial fan that fed the Cortes de Baza area
Problemática de las calizas del Cretácico Superior en las cimentaciones de Oviedo
(Sociedad Geológica de España, 2004) Gutiérrez Claverol, M.; Pando, Luis; González, B.
In rocky substratum of Oviedo (N Spain) there is an important carbonate formation of Upper Cretaceous age. This level has interest into applied geology on having supposed a surface of preferential foundation for city buildings and, in fact, mechanical laboratory tests show that its geotechnical behavior is very good. Nevertheless some punctual deficiencies like karstification processes appear at these limestones, involving a certain risk of zonal failure in structures foundations
Precisiones sobre la cinemática y edad de la falla del Río de la Miel (Maro, Málaga)
(Sociedad Geológica de España, 2004) Pérez Ramos, Isaac; Sanz de Galdeano, Carlos; Andreo Navarro, Bartolomé; Pistre, S.
The Río de la Miel fault shows a complex movement history. Three main displacement stages have been distinguished from the microtectonic analysis. The first stage was a dextral strike-slip movement whose cr, was almost horizontal with, a NNW-SSE direction. The second stage was a normal movemént with cr, situated in the vertical. Finally, in the third stage, cr, had a low dipping angle and a NNE-SSW direction. The vertical displacement of the fault reach several hundreds of metres, probably more than 500. m. This fault has been active at least during the lower Pliocene
Peligrosidad Natural en el Espacio Protegido de las Batuecas-S Francia, Quilamas y su entorno (Salamanca). Análisis integrado de los factores potenciales de riesgo
(Sociedad Geológica de España, 2004) Martínez Graña, Antonio Miguel; Goy, José L.; Zazo, C.
The Natural Hazards Cartography show a basic utility in the land planning. In this paper; in order to actual erosion risk characterized for vegetation, climatics parameters, geomorphologic domains and litology; and based on the study of geotechnic cartography in order to parameters of litology, hydrogeology and geomorphology; is to obtain a geologic risk cartography, shows areas of High - medium - low geologic hazards. The zones shows the risk and motives, in order to thematic cartography. The results permit zones characterized with use recommendations in Quilamas and Batuecas-S.Francia Natural Parks; for environmental management effective in the land planning
Paleometeorización vs. Paleoalteración en la superficie de discordancia Proterozoico-Cámbrico en el Antiforme del Narcea
(Sociedad Geológica de España, 2004) Gutiérrez Alonso, Gabriel; Blanco Sánchez, J. A.; Macfarlane, A.; Fernández Suárez, Javier
Petrographic and geochemical characterization of the rocks underlying the Neoproterozoic-Cambrian angular unconformity in the eastern flank of the Narcea Antiform, provide an insight on the processes involved in the widespread ruhefaction present along this contact. The'data provide evidence of superposed events related to the sub-aerial weathering during the Precambrian-Cambrian boundary and a further alteration caused, probably,; by fluid circulation during the Variscan Orogeny
Observaciones hidrogeológicas en el área urbana de Granada
(Sociedad Geológica de España, 2004) Benavente Herrera, José; Sánchez Díaz, L.; Castillo, A.
A number of hydraulic tests, as well as monitoring of groundwater level and physico-chemical variables, have been carried out -since their construction in August 2000- in two adjacent wells located inside the urban area of Granada, which extends over the eastern border of the Vega de Granada alluvial aquifer. Other nearby wells out of the urban area were also monitored. The results indicate a phreatic (S=0,25), transmissive (T =3000 m2/d) aquifer, with flow velocity values of around 4 m/d. Clayey levels, relatively abundant in this sedimentary environment, induce the presence of a perched groundwater level that seems to leak into a deeper one through the gravel pack of one of the boreholes. Groundwater in the studied area has electrical conductivity in the range 600-1300 mS/cm, and bicarbonate-sulfate calcium-magnesium type. The recharge from the main stream is characterized by low mineralization values (300 mS/cm). The infiltration of urban wastewater must account for the relatively high nitrate contents -as well as for some microbiological indices- found in the water of the studied wells
Nuevos datos sobre la geologia del Complejo Intrusivo Alcalino de Monchique (SW de Portugal)
(Sociedad Geológica de España, 2004) Valadares, V.; González Clavijo, Emilio J.
Los estudios microscópicos complementarios de las rocas alcalinas han permitido confirmar la estructura anular groseramente concéntrica del Complejo de Monchique, semejante a la que presentan los complejos alcalinos coetáneos de Sintra y Sines. La zona central está constituida por sienitas nefelínicas de grano grueso, rodeadas por un anillo de sienitas nefelínicas heterogéneas de grano más fino. En esta unidad exterior, y localmente separando ambas unidades, existen cuerpos menores de rocas básicas y ultrabásicas con feldespatoides y de brechas de diferentes tipos. Su forma groseramente elíptica con eje mayor en WSW-ENE, junto con las relaciones con el encajante, permiten proponer un mecanismo de emplazamiento en los niveles altos de la corteza a favor de un conjunto de fallas de la misma dirección, posiblemente de edad varisca y reactivadas durante los primeros episodios de la orogenia alpina
Nueva localidad fosilífera en el mioceno inferior de las Bárdenas Reales de Navarra (cuenca del ebro, península ibérica)
(Sociedad Geológica de España, 2004) Murelaga, Xabier; Larrasoaña, J. C.; Garcés Crespo, Miguel
In this study we report a new fossil locality found in the continental sediments of the Tudela Formation. This formation is composed of palustrine, lacustrine and distal aluvial fades that represent the sedimentary filling of the west-central sector of the Ebro basin during the Ramblian and Aragonian (lower Miocene). Based on the study of micromammals remnants, the new fossil locality can be placed within the Ramblian biozone Z
Moluscos y microvertebrados del Pleistoceno de las terrazas del río Tajo en Toledo y Fuentidueña de Tajo (España Central)
(Sociedad Geológica de España, 2004) Sesé, C.; Aparicio, M. T.; Pérez González, Alfredo
The study of the terraces and its associated faunas from the areas of Toledo and Fuentidueha de Tajo in the Valley of the Tagus River, mainly from a palaeoenvironmental point of view, has been made in this work. Six new sites of fossil microvertebrates and fossil molluscs were found when this work was undertaked. Many of the sites with remains of microvertebrates and all the sites with fossil mollucs that were found in that prospecting are presented for the first time in this work. As regards to the last, it can be remarked that all the shells of the molluscs find out are of a very small size. That could be the consequence of the alloctone origin as it happens in the seasonal river side flooding. This suggestion is supported by the presence of freshwater and terrestrial species mixed in the same sample, as, for example, Succinea putris (characteristic biotope of humid areas near the river side), together with Helicella madritensis with a terrestrial habitat. The conditions of life of the twelve species of mollucs here analyzed suggest a temperate climate in the Middle Pleistocene at the time of the sites deposition, similar to the present day in the area. Besides, the presence of Helicella madritensis, a xerophillus species that lives today in the arid areas of the central plateau of the Iberian Peninsula, suggests a climate with large dry periods not very different from now. The habitat of Truncatellina cylindrica (very dry calcareous grassy or rocky places) and that of Vallonia costata (dry open calcareous places) supports the sames suggestions
Magmatismo Neoproterozoico calcoalcalino en el Antiforme del Narcea (N de España)
(Sociedad Geológica de España, 2004) Cuesta, Andrés; Gallastegui, G.; Suárez Hernando, Oier; Rubio Ordóñez, Álvaro
4 sequence of acid to basic igneous rocks is exposed within Neoproterozoic sediments of the Narcea Antiform (N of the Iberian Variscan Belt). Volcanic and volcanoclastic rocks, classically known as 'porphyroids', are rhyolites to andesites in composition. Cranodioritic to quartz-dioritic or gabbroic rocks are intrusive into the metasedimentary sequence and the volcanic rocks. Finally, hypabissal basaltic dykes are found cross cutting both the extrusive and intrusive rocks. The best outcrops of igneous rocks occur along the Tineo-Cilldn area forming, near Tineo, a continuous sequence ca. 350 m thick of volcanic-volcanoclastic units and basaltic dykes. Original igneous textures are preserved where deformational processes barely affected the sequence, whereas secondary mineral assemblages - spilitized rocks - reflect hydrothermal and/or metasomatic processes. Whole rock composition of the igneous rocks has a calc-alkaline affinity and reflects a crustally contaminated mantle signature

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