Geogaceta -- Nº 05, (1988)

Permanent URI for this collectionhttps://hdl.handle.net/10272/18209

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Una modificación al modelo genético para la Formación Molicias (Tortoniense superior, Depresión de Guadix, S de España)
(Sociedad Geológica de España, 1988) Vera, J. A.; Rodríguez Fernández, José
The Molicias Formation has traditionally been interpreted as being a basinward prograding, platform-talus-basin system, deposited in a relatively rising-sea-level environment. The proposed modification to this model is that the greater part of the turbidite ar the result of brusque drops in sea level which caused erosion of part of the platform and the consequent redeposition of reworked material within the deeper parts of the basin
Sobre el adelgazamiento mioceno del Dominio Cortical de Alborán, el Despegue Extensional de Filabres (Béticas orientales)
(Sociedad Geológica de España, 1988) García Dueñas, V.; Martínez Martínez, J. M.
In the Alboran Domain, the Alpujarride/Nevado-Filabride major boundary is a brittleductile and brittle detachment (Filabres Extensional Detachment, FED) which thinned the Nevado-ñlabride complex during the Miocene. The FED and their associated Iow-angle normal faults in the footwall cut across the Calar Alto and Bédar-Macael nappes, decreasing complex thickness by more than 5 km. The angle between the fault zones and the mylonitic foliation of the Nevado-Filabride shear zones is <20º and very often <10º, the hangingwall being displaced towards N190-270E (maximum SW). The FED, folded during the Upper Miocene, is consistent with the variation of the crustal thickness between the Northern Sierra Nevada and the Mediterranean coastal region (Alboran crustal thinning)
Sobre la existencia de dos cuñas de corteza en Galicia oriental según resultados de sísmica profunda. Implicaciones geodinámicas
(Sociedad Geológica de España, 1988) Vegas, Ramón; Córdoba, D.
A silice of granulites has been interpreted from deep seismic sounding data at a depth of 8 km in eastern Galicia (NW Spain). This leads to the definition of the sole Hercynian thrust and two different crustal wedges that result from the asymmetrical shortening of the continental crust
Significado paleogeográfico de las texturas y acumulaciones de carbonatos en perfiles edáficos de la Unidad Intermedia del Mioceno de la Cuenca de Madrid (prov. de Guadalajara)
(Sociedad Geológica de España, 1988) Alonso Zarza, Ana María; García del Cura, María Angeles; Calvo, J. Pedro
The presence as well as types of pedogenic carbonate deposits within miocene formations of the NE Madrid Basin are mainly linked to two major differentitated environments: a) proximal alluvial fan environments and b) distal alluvial fan and flood-plain environments. The pedogenic profiles developed in palustrine areas show sorne features also found in b) deposits. In a broad sense, both mesoscale and textural features (Fe-Mn oxides remobilization and carbonate accumulation) of the pedogenic profiles display some variety resulting from different sedimentation rates, substrate nature and water hosting, all the parameters being controlled by paleogeography
Sedimentos fluvio-lacustres en la base de la megasecuencia Hauteriviense Sup,-Aptiense, borde meridional de la cuenca de los Cameros, provincia de Soria
(Sociedad Geológica de España, 1988) Clemente Vidal, Pilar
The Hauterivian-Aptian siliciclastic Megacycle, continental in origin, has been divided into four litoestratigraphic formations, grouped into two depositional sequences that are separated by unconformities. The first depositional sequence is coarsening-upward and the second coarsening-fining. The basal unit that appears in the eastern part of the area (Mb. Golmayo) is interpreted as deposited in meandering fluvio-lacustrine environment, with a complex flood plain, where shallow carbonated lakes abounded. The depositional style of the unit reveals periodic tectonic rejuvenations of the Las Fraguas fault that constituted the soutwestern margin of the basin
Primeros datos sobre el esqueleto postcraneal de Protapirus cetinensis (Tapiridae)
(Sociedad Geológica de España, 1988) Cerdeño, Esperanza
The tapirid species Protapirus cetinensis was recently described upon a few dentary remains coming from the sites of Cetina de Aragón (Zaragoza) y Valquemado (Cuenca). The excavation carried out in summer 1987 in Valquemado has yielded the first postcraneal element of Tapiridae from the Spanish Lower Miocene. lt is a third metatarsal of a young individual that lacks the distal epiphysis. lt is a very long bone that shows a very greater gracility than the extant Tapirus terrestris, the only species we have some direct data. P. aginensis from La Milloque (Francia) is also a slender tapir but the metapode we have studied is not homologous to that of Valquemado
Presencia de la discontinuidad sárdica en la Zona Cantábrica
(Sociedad Geológica de España, 1988) Aramburu, C.; García Ramos, José Carlos
The «sardic unconformity» (near the Cambrian-Ordovician boundary), ocurring in the middle part of the Armorican Quartzite-Barrios Fm., is for the first time reported in the Cantabrian Zone. A close comparison with the Cambro-Ordovician successions in other regions is then possible, having important tecto-sedimentary conclusions
Morfología de un margen de plataforma carbonatada en el Carbonífero Superior de la Zona Cantábrica
(Sociedad Geológica de España, 1988) Bahamonde, Juan R.; Colmenero, Juan Ramón; Heredia, N.
The main aim of this paper is to describe a intrashelf carbonate margin in the Westphalian rocks of the Ponga Nappe Unit (Cantabrian Zone). lt concerns to the Escalada limestone Fm. at the Tiatordos height, near Beleño village
Los castores del Pleistoceno medio de Atapuerca (Burgos, España)
(Sociedad Geológica de España, 1988) Gil Bazán, E.
This work is a description of the Castor fiber fossils remains found in the Karst fillings of Atapuerca (Burgos, Spain)
La utilización de la anisotropía de la susceptibilidad magnética (ASM) en el estudio de la deformación finita: ejemplo en la zona milonítica de Cap de Creus (Catalunya)
(Sociedad Geológica de España, 1988) Parés, J. M.
The magnetic susceptibility anisotropy (MSA) of the Roses Granodiorite has been studied The magnetic fabric is due to the shear zones that affect these rocks. In this sense, the kmin axes of the MSA are paralel to the foliation poles and the kmax axes are parallel to the direction of the mineral elongation measured in the field The Flinn-type diagram to study the ellipsoid shape indicates oblateness of the MSA ellipsoid
Las tierras raras en el Plutón de Caldas de Reyes: influencia de la mineralogía en su evolución
(Sociedad Geológica de España, 1988) Cuesta, Andrés; Corretgé Castañón, Luis Guillermo
This paper deals with the role of the mineral phases in the evolution and behaviour of the REE elements in the Caldas de Reyes Zoned Pluton (Galicia-Spain). The study of normative and chemical relationships reveals the preponderant influence of the accesory minerals over REE spectra of the Pluton
Las facies de plataforma carbonatada del Jurásico inferior y medio en la Sierra de Cazorla (Zona Prebética)
(Sociedad Geológica de España, 1988) Acosta, P.; García Hernández, M.
The Lower and Middle Jurassic sediments of the Prebetic Zone correspond to the first phase of development of a shallow-water platform. They constitute a transgressive depositional sequence containing some minor shallowing-upward elementary sequences inside
Las deformaciones hercinianas tardías en la región de Santa María la Real de Nieva (Sistema Central Español)
(Sociedad Geológica de España, 1988) Álvarez, F.; González Lodeiro, Francisco; Martín Parra, L. M.
The precambrian and paleozoic materials of Santa María la Real de Nieva outcrop has been affected by two Hercynian shear systems which developed after the main deformation phases and the intrusion of the granite rocks. The first shear system is composed of subvertical, dipping northwards, senestral wrench faults trending ENE-WSW. The second is a Iow-angle extensional system with the hanging wall descending westwards
La ankeritización en las dolomías del Aptiense en el entomo de las mineralizaciones Pb-Zn en el NO de Cantabria
(Sociedad Geológica de España, 1988) Bravo, J. I.
The study of iron content in dolomites from northwestern Cantabria is used to know the ankeritization degre in dolomites but also the biggest or lowest proximity to Pb-Zn mineralization, provided that these mineralizations are inserted in dolmains with high iron content
Interferencia de plegamientos alpinos en el tercio occidental del Arco Vasco (Cuenca Vasca)
(Sociedad Geológica de España, 1988) Martínez Torres, Luis M.; Morales, Tomás; Ramón Lluch, R.; Ibarra, V.
On the occidental part of the Basque Arch (Basque Bassin), the Trias Keuper outcrops network deal With the intersection of a pre-Albian «en echelon» folding With the tertiary alpine deformation
Gabros coroníticos en el macizo cristalino de Toledo
(Sociedad Geológica de España, 1988) Barbero, Luis; Villaseca, Carlos
The Bastida gabbros massif is formed by olivine norites and piroxene gabbronorites. The metamorphic conditions are those of the intermediate to Iow pressure granulite facies, producing the coronitic texture that exhibit this gabbros
Fracturación en los metápodos de Hipparion
(1988) Alcalá, Luis; Martín Escorza, Carlos
The fractures observed in a sample of 96 fossil metapodes of Hipparion are studied in this paper. The specimens come from several sites of different Cenozoic basins of Spain. All the bones but one have at least one post-fossilization fracture of load process origin. The bones were divided in eleven segments. The number of fractures in the intervals were put in a histogram. From the histogram it became clear that certain intervals were more liable to have fractures than others. The maximum number of fractures is a direct function of the geometric features of the bone. The anteroposterior diameter has an inverse relation to the fracture frequency. Where the greatest changes in tranverse bone diameter occur also the greatest frequences in fractures occur
Fosfatos de Mn-Fe con Li en el área pegmatítica del Cap de Creus (Cataluña)
(Sociedad Geológica de España, 1988) Corbella, Mercè; Melgarelo, J. C.
Lithium-bearing phosphates have been recently discovered in the albitic facies of the pegmatitic field of Cap de Creus. New metallogenetic possibilities are, hence, expected in the Eastern Pyrenees
Fase Robledo: Una etapa distensiva dúctil en la Cordillera Central
(Sociedad Geológica de España, 1988) Martín Escorza, Carlos
Shear with SC planes are found in the same locations among the gneises and other metamorphic rocks in the Central Cordillera. They are a ductil tectonic extensional episode (Robledo Phase) with SE-NW dipping C shearing planes. The observations suggests an age post-Hercynian and previous, or in relation, to tardi-Hercynian transcurrent fault episode
Factores intrínsecos que condicionan la alteración de la arenisca de la Colegiata de Santillana del Mar (Cantabria)
(Sociedad Geológica de España, 1988) Ordaz, Jorge; Alonso, F. J.; Esbert, R. M.
The petrographical characteristics and sorne physical properties of the sandstone used in the construction of the Cloister of the «Colegiata» of Santillana del Mar (Cantabria, Spain), are studied in order to establish the intrinsic factors conditioning their alteration

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