Geogaceta -- Nº 22, (1997)

Permanent URI for this collectionhttps://hdl.handle.net/10272/10516

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Variaciones de la anisotropia de la susceptibilidad magnética en turbiditas albienses de la Cuenca Vasco-Cantábrica
(Sociedad Geológica de España, 1997) Badillo, J. M.; Aranguren, A.; Cuevas, Julia; Tubía, José María
The first results extracted from the study of the Anisotropy of magnetic susceptibility (ASM) from 33 turbidites allocated in Basque-Cantabrian basin show the validity of the ASM as a rock fabric analysis tool to determine deposit mechanism and paleocurrents in turbidites
Un sistema turbidítico Bartoniense de tipo «channel-levee» en la Cuenca de Pamplona: implicaciones tectónicas y paleogeográficas
(Sociedad Geológica de España, 1997) Payros, Aitor; Pujalte, Victoriano; Orue Etxebarria, Xabier; Baceta, Juan Ignacio
The Bartonian Ezkaba Sandstone, in the Pamplona Basin,.seems.to represent channel-fill deposits of a laterally migrating ch.annel-levee turbidite.system. Its silicidastic nature and its northern derivation indicate the contemporaneous emergence of the orogenic inner zones .in the western Pyrenees
Un leopardo, Panthera pardus (Linnaeus, 1758), en el Pleistoceno de la Cueva de los Torrejones (Tamajón, Guadalajara, España)
(Sociedad Geológica de España, 1997) Arribas, A.
The most complete individual of Panthera pardus (Linnaeus, 7 758) of the Spanish Pleistocene has been found in the Torrejones Cave. The importance of this material stands on two facts: V for the first time in a Spanish site the fossil remains of the postcraneal skeleton have appeared associated to craneal remains of the same being, and 2) the evidences of human activity on the skeletal elements of the carcass offer criteria which explain the remains completeness
Trazas de minerales evaporíticos en el Albiense superior de Bi Haizpeak/ Dos Hermanas (Aralar, Nafarroa): implicaciones paleotectónicas
(Sociedad Geológica de España, 1997) Lertxundi, D.; García Mondéjar, Joaquín
Pétrographie analysis of a thin (50 cm) bed from the Upper Albian Bi Haizpeak/Dos Hermanas (Aralar) unit, has shown signs and traces of evaporitic minerals. These features mainly consist of gypsum inclusions, micritic feplacements of gypsum crystals, and authigenic quartz cristals with anhidrite and gypsum inclusions. This is the first reference to Albian evaporites in the Basque-Cantabrian Basin, wihch, on the other hand, were formed in a general humid climate. We attribute these sulphate minerals to anomalous sedimentary conditions, related to a pulse of local ascension ofKeuper salt through synsedimentary faults
Tectónica extensional cretácica en la subcuenca de Oliete (Cordillera Ibérica central)
(Sociedad Geológica de España, 1997) Soria, Ana Rosa; Meléndez Hevia, Alfonso; Liesa, Carlos L.
The control of the extensional tectonics on the geometry of the Oliete Subbasin during Early Barremian-Basal Aptian (Early Cretaceous) is examinated. Both, the main NW-SE trending of the basin, its asymetrical geometry and the location of the depocenters was controlled by the reactivation of NW-SE and NE-SW Late Variscan faults, and the formation of new faults. We propose that the general geometry of the basin is controlled by a flexion in the cover, with some associated minor normal faults. The southwestern margin of thé basin was probably related to the reactivation of a Late Variscan fracture as NW-SE northeasthern-dipping normal fault in the basement. The internal structuration is controlled by NE-SW southeasthern-dipping normal faults
Secuencia evolutiva de los depósitos resedimentados eocenos de Punta Galea, Bizkaia: relevancia para determinación del sentido de transporte en láminas de «slump»
(Sociedad Geológica de España, 1997) Pujalte, Victoriano; Payros, Aitor; Orue Etxebarria, Xabier; Baceta, Juan Ignacio
The middle Eocene succession of Biscay contains numerous and thick intercalations ofslump-turbidite couplets. They record a simultaneous resedimentation of both deep and shallow water deposits, most probably trigered by contemporary earthquakes in the western Pyrenees. Many of the slump sheets exhibit an imbricated internal structure, which clearly reflects piling up of basinal-derived debris-flows. The attitude of such large-scale imbrications demonstrates a southern transport direction for the debris-flows
Ramp calcarenite sheet depositional system as a recorder of sea-level fluctuations (Late Albian, Alsasua, Spain)
(Sociedad Geológica de España, 1997) Fernández Mendiola, Pedro Ángel; Quintanar Soto, A. B.
The Albian Aitziber calcarenites (Alsasua, Navarra) are analysed on the basis of their overall geometry, types of limiting boundaries, internal composition, facies, sedimentary structures and paleogeographical context. An «in situ» origin in shallow-water is inferred. The base of the calcarenite sheet represents an abrupt shallowing relative to the underlying basin. The top of the calcarenite records a drowning, hardground and a hiatus between the upper Albian and the upper Cretaceous. Sea level fluctuations related to a local tectonic origin were responsible for the calcarenite inception and demise
Primera cita del género Capra en el Pleistoceno medio de la Sierra de Atapuerca (Burgos, España)
(Sociedad Geológica de España, 1997) Sánchez Chillón, B.
The first caprinae remains found in the Sierra de Atapuerca are described herein. The scarce material comes from the Galería deposit (TC) in the Trinchera del Ferrocarril of Atapuerca (Burgos), of middle Pleistocene age. Despite the few remains recovered, the comparisons with other European lower and middle Pleistocene Caprinae, also scarce, let no doubts about their taxonomic identification as Capra sp.
Presencia de Marmota marmota en los rellenos kársticos de Atapuerca (Burgos, España)
(Sociedad Geológica de España, 1997) Gil Bazán, E.
In this work are described the more old fossil record of Marmota marmota of the european Pleistocene, in the levels of Lower Pleistocene (TD6), and Middle Pleistocene (TN4, TD10) from the Trinchera del Ferrocarril of Atapuerca (Spain)
Moluscos bivalvos de las facies cuarcíticas del Ordovícico Inferior centroibérico
(Sociedad Geológica de España, 1997) Gutiérrez Marco, Juan Carlos; Babín, C.; Porro Mayo, T.
Some scarce and bad preserved bivalves have been described from few localities lying at the upper part of the Armorican quartzite facies in Central Spain. Middle Arenig faunas include two palaeotaxodont forms (Praenucula oehlerti and Cardiolaria sp.), and two different palaeoheterodonts (Modiolopsis sp. and ?Actinodontoida indet.). Previous reports of other Arenig bivalves, especially actinodontoids, from coeval quartzites of northwestern, Central and northeastern Spain, as well as from Central Portugal, have been also briefly examined. The Iberian faunas show close affinities with the well known Arenig assemblages from the «Grès armoricain» of Western France, and add new data for the scenic reconstruction of the Lower Ordovician bivalve radiations on the northwestern Gondwanan shelves
Modificaciones diagenéticas en nodulos de sílex por influencia de fluidos dolomitizantes: ejemplos en el Cretácico superior de la Región Vasco-Cantábrica
(Sociedad Geológica de España, 1997) Erkiaga, M.; García Garmilla, Francisco; Elorza, Javier
Special nodular chert detected in carbonates of the Upper Cretaceous in the Basque-Cantabrian Region was partially or completely modified by diagenesis. Rhombohedral dolomite crystals appear both within the carbonate host-rock and the interior of chert nodules. Unlike the common unaltered nodular chert from other sections or stratigraphic horizons, the dolomitized chert shows an enhancement of secondary porosity and suggests the Mg-rich fluids in alkaline environment were responsible for diagenetic modification
Mineralogía de arenas y edad en una secuencia de superficies entre el río Tajo y los Montes de Toledo
(Sociedad Geológica de España, 1997) Pardo, E.; Marfil Pérez, Rafaela; Espejo, R.
We study the heavy minerals in the fine sand from Bt horizons of soils developed in a serie of surfaces related to the Tajo river and Los Montes de Toledo. We found a sequence in the weathering degree of the detrital deposits which is according to the supposed age of the surfaces
Los rizolitos de la Fm. Aguilar (Kimmeridgiense-Berriasiense, Palencia, Burgos y Cantabria): caracterización, génesis y significado
(Sociedad Geológica de España, 1997) Hernández, José María; Pujalte, Victoriano; Robles, Sergio
Four diferents types of rizoliths have been recognized within the alluvio-lacustrine deposits that made up the Aguilar Fm. On the base of their macroscopic and microscopic features and of the sedimentology of the facies association in which they occurred, a genetic model is proposed for each of them
Los micromamíferos del tránsito Pleistoceno inferior-medio de Atapuerca (Burgos,España). Implicaciones bioestratigráficas y evolutivas
(Sociedad Geológica de España, 1997) Gil Bazán, E.
The micromammals association of the TD5- TD6 levels is exclusive from the karstic complex of Atapuerca (Burgos, Spain). This association is characterized by the presence of arvicolids : Terricola gregaloides, Terricola huescarensis, Terricola subterraneus, Microtus brecciensis, Arvicola chalirei, Mimorriys savini, Pliomys episcopalis, together two new rodent species: Terricola seseae nov. sp. and Microtus iignani nov. sp.. This fauna seems to correspond to the transit Lower Pleistocene - Middle Pleistocene, with more than 780.000 years ago, near of Matuyama/ Brunhes boundary
Los granates como guía de exploración y materia prima: El ejemplo del Hoyazo de Níjar en el cinturón metalogenético del SE Ibérico
(Sociedad Geológica de España, 1997) Lunar Hernández, Rosario; Martínez Frías, J.; Benito, R.; Wolf, D.
A review of the garnet-rich volcanic Complex of El Hoyazo (SE Spain) is given, including new data about the petrology and geochemistry of the volcanic area, and suggesting a methodological proposal for evaluating the use of garnets as a guide to mineral deposit exploration. This is significant as the Neogene volcanic region of SE Spain hosts a wide variety of mineral deposits making up a metallogenetic belt from Cartagena to Cabo de Cata: Pb-Zn (± Ag,Sb) (Mazarron, Sierra Almagrera), Sb-Hg-Ba (±Au) (Valle del Azogue), Fe-Mn-Ba-Ag (Las Herrerías), native Au (Rodalquilar). The current exploitation of the garnets as industrial raw material is also described
La sucesión lacustre pliocena de Villarroya (La Rioja). Principales características paleoambientales basadas en ostrácodos y moluscos
(Sociedad Geológica de España, 1997) Rodríguez Lázaro, Julio; Robles, Fernando; Martín Rubio, Maite; Anadón, P.; Utrilla, R.; Vázquez, A.
Two main episodes have been distinguished in the Pliocene lacustrine sequence of Villarroya (La Rioja, Spain) on the basis of the ostracode and mollusc faunal assemblages. The early episode, which corresponds to a relatively deep lacustrine environment, is recorded in two sequences. Most of the lower sequence may represent oligohaline, bicarbonated waters, with noticeable salinity variations, taking into account the presence of Parathetyan-like ostracodes. The second lacustrine sequence and upper part of the lower sequence correspond to oligohaline to mesohaline waters, recording a chloride character in its upper part. The late episode corresponds to a shallow, palustrine-like setting with temporary ponds feed by sources, and relatively cold, non-carbonated water, as revealed by the ecological features of terrestrial and aquatic gastropods and ostracodes
Las estructuras paleokársticas del Monte Baio (Araba/Alava): su relevancia para una evaluación cuantitativa del descenso del nivel marino del Paleoceno medio
(Sociedad Geológica de España, 1997) Baceta, Juan Ignacio; Pujalte, Victoriano; Payros, Aitor
During the period of sub-aerial exposure subsequent to the mid-Paleocene sea level fall, a set of paleokarstic features were generated in upper Danian lagoonal limestones of the Alava province. The most interesting of them all, and potentially the more meaningful, is a horizontal dissolution horizon, possibly recording the position of the upper surface of a paleophreatic zone. If that possibility is correct, the magnitude of the mid-Paleocene sea level fall would be narrowly constrained to circa 40 m/a more realistic figure than those previously estimated for this event
Las asociaciones de foraminíferos bentónicos de la serie margo-diatomítica de Sidi Haj Youssef (Boudinar, Marruecos nord-oriental)
(Sociedad Geológica de España, 1997) Rachid, A.; El Hajjaji, K.; Civis-Llovera, Jorge
The Messinian section of Sidi Haj Youssef (Boudinar basin- NE. Morocco) with alterancy of marl and diatomitic levels, is very rich in benthonic foraminifera and wich are represented by 102 species. The quantitative studies reflected different conditions in relation to the diatomitic and marls levels. The association of foraminifera and paleoecologic indices, in diatomitic levels, are according with de upwellings influences and the associations in the marl levels, with normal marine conditions. By the other hand, the associations reflected the bathymetric conditions during the Messinian
Las areniscas de la Formación de Gordexola (Albiense, flanco sur del Anticlinorio de Bilbao, Vizcaya) II: Cementación y diagénesis
(Sociedad Geológica de España, 1997) Zuluaga, María Cruz; García Garmilla, Francisco; Arostegui García, Javier
The sandstones of the Gordexola Formation were studied using petrography, cathodoluminescence, electronic microprobe, SEM, and C and O isotopic relations. A diagenetic sequence was inferred from medium to late stages. The processes that affected sandstones occurred from syntaxial siliceous cements to different carbonates that precipitated and replaced previous felsdpar grains. Temperatures of late diagenesis could oscillate from 40° to 45° C. The very late diagenesis consisted on deformation of both grains and crystals under burial conditions
Las areniscas de la Formación de Gordexola (Albiense, flanco sur del Anticlinorio de Bilbao, Vizcaya) I: Composición y procedencia
(Sociedad Geológica de España, 1997) Zuluaga, María Cruz; García Garmilla, Francisco; Arostegui García, Javier
The sandstones of the Gordexola Formation have been petrologically and geochemically studied. The averageofQ(= 57%), FdK+Plag(= 6%) and rock fragments (= 4%) in sandstones was plotted against the Dickinson et al. (1983) and Suttner and Basu (1981) diagrams. Compositional trends of mica and accessory minerals reinforce the idea of the Hesperian Massif as the most probable provenance area for the Gordexola sandstones. The measured paleocurrents (mean N200) support this affirmation

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