Estudio geológicos del área esquitosa de Galicia Central (zona de Lalín-Forcarei-Beariz)

[Resumen] Las investigaciones efectuadas en el sector Norte del Area esquistosa de Galicia Central han permitido diferenciar tres grupos litoestratigráficos en el conjunto de metasedimentos que aflora en esta zona. Todos los materiales han sido sometidos a una deformación polifásica, cuyas estructuras pueden agruparse en 3 fases principales, además de algunas estructuras tardías. Esta deformación está acompañada de un metamorfismo regional de intermedia-baja presión que alcanza condiciones de la facies de las anfibolitas. En este trabajo se discute además, en base a distintos argumentos, el carácter poliorogénico y alóctono propuesto por autores precedentes para las denominadas Unidades de Lalín y Forcarei.[Abstract] Three main lithostratigraphic groups have been distinguished in northern part of Central Galician Schist Area. Al! these materials have suffered a polyphasic deformation, whose structures can be grouped in three main phases, and some later structures. A regional syntectonic metamorphism of intermediate-Iow pressure reaching anfibolite facies occurs. The polyorogenic and allochthonous character of the Lalín and Fortarei Units, suggested by earlier authors, is discusse

El complejo de dunas eólicas de la Playa de Frouxeira (Meirás-Valdoviño, La Coruña)

[Resumen] Dentro del complejo dunar, situado en la parte posterior de la playa de Frouxeira, se han distinguido varios tipos de dunas : montículos aislados, remontantes, parabólicas y blow-outs y cartografiados en cuatro subzonas: dunas activas, subrecientes, remontantes y fósiles. Se establecen las características texturales de las arenas dunares y de playa, tanto granulométricas como a partir de los índices de correlación lineal entre los diferentes parámetros, además del contenido carbonatado. Finalmente, se determina la evolución sedimentaria y su relación con el resto de la cornisa cantábrica, mediante los datos prehistóricos asociados al medio de depósito[Abstract] Several coastal sand dunes are classified ( isolated mounds, climbing, parabolic and blow-outs ) and they are distributed in four areas: active, subrecent, climbing and fossil ones. Textural patterns as well granulometric parameters as lineal correlation index among them are stablished. Finally, the sedimentary evolution is determlnated by the help of the prehistoric information from the Asturian and Cantabrian region

Nuevas aportaciones al conocimiento de la evolución tectonometamórfica del complejo de Cabo Ortegal (NW de España)

[Resumen] El Complejo de Cabo Ortegal es una unidad a16ctona constituida en gran parte por rocas ultrabásicas, básicas y neises. Estas rocas han sufrido un metamorfismo polifásico en el que se distinguen cuatro episodios, de forma que el grado más elevado se alcanza durante la primera fase (facies granulita y eclogita), teniendo lugar después una retrogradación progresiva hasta la facies de los esquistos verdes. La evolución de la deformación ha tenido también lugar en cuatro fases, de forma que la primera es posterior a los dos primeros episodios metamórficos. Las tres primeras fases de deformación representan una importante deformación por cizalla tangencial, mientras que la cuarta da lugar al amplio sinforme en cuyo núcleo se sitúa el complejo. Las rocas de Cabo Ortegal representan probablemente una secuencia ofiolítica subducida durante el Ordov!cico y obducida con posterioridad al Devónico inferior como con secuencia de una colisión continental.[Abstract] The Cabo Ortegal Complex is an allochthonous unit made up of ultrabasic rocks, basic rocks and gneisses. These rocks have suffered a poliphasic metamorphism in which four episodes can be established. The highest degree of metamorphism (granulitic and eclogitic facies) took place during the first phase followed a~erwards by a progressive retrogresion to greenschist facies. Four phases of deformation can also be distinguished being the first later than the first two metamorphic episodes. The three earlier tectonic phases represent an important sheardeformation while the forth gives way to the wide sinform of Cabo Ortegal. The rocks of the Cabo Ortegal Complex would be an ophiolitic sequence subducted during Ordovician times and obducted after the lower Devonian, due to a continental collision

Interaction of 8 He with 208Pb at near-barrier energies: 4 He and 6 He production

Spanish Ministry of Economy and Competitiveness-FPA-2010-22131-CO2-01 (FINURA) y FPA2013-47327-C2-1-RMinistry of Science and Higher Education of Poland-N202 033637National Science Centre of Poland-2013/08/M/ST2/00257 (LEA-COPIGAL) y 2014/14/M/ST2/00738 (COPIN-INFN Collaboration)European Science Foundation-EUI2009-04163432 (EUROGENESIS

Elastic scattering of 8He + 208Pb at 22MeV

The dynamics of 8He around the Coulomb barrier is investigated by measuring the energy and angular distribution of the elastic 8He and the 6He and 4He fragment yields in the collision process with a 208Pb target. The experiment was carried out at SPIRAL/GANIL in October 2010. The experimental results will provide information about the relevant reaction mechanisms and the validity of the optical model (OM) when applied to exotic nuclei. In this paper, details of the experimental setup and preliminary results on the elastic scattering for the collision at 22 MeV are presented.Spanish Research Council FPA-2010-22131-CO2-01Ministry of Science and Higher Education of Poland N202 03363

GLORIA: A compact detector system for studying heavy-ion reactions using radioactive beams

Abstract The GLObal ReactIon Array (GLORIA) has been designed in order to study direct nuclear reactions induced by exotic nuclei at energies close to the Coulomb barrier. The detector array consists of six silicon particle-telescopes arranged in a very close geometry around a 30 • rotated-target system, allowing the measurement of reaction fragments in a continuous angular range from 15 • to 165 • (Lab.). GLORIA has been used for the first time at the SPIRAL/GANIL facility at Caen (France) to study the scattering of the system 8 He+ 208 Pb at the collision energies of 16 and 22 MeV

Scattering of 8He on 208Pb at Energies Around the Coulomb Barrier

We have measured the angular distributions of elastic scattering and 6,4He fragments produced in the collisions of an exotic beam of 8He on a 208Pb target at laboratory energies of 18 and 22 MeV, just around the Coulomb barrier (19 MeV). The measurements were performed at the SPIRAL/GANIL facility in Caen, France. In this paper, we present preliminary data on elastic cross sections and discuss the results using optical model and coupled reaction channel calculations.Spanish Research Council FPA-2010-22131-C02-01Ministry of Science and Higher Education of Poland No. N202 03363

Revealing the last 13,500 years of environmental history from the multiproxy record of a mountain lake (Lago Enol, northern Iberian Peninsula)

This is the author's accepted manuscript. The final publication is available at Springer via http://dx.doi.org/10.1007/s10933-009-9387-7.We present the Holocene sequence from Lago Enol (43°16′N, 4°59′W, 1,070 m a.s.l.), Cantabrian Mountains, northern Spain. A multiproxy analysis provided comprehensive information about regional humidity and temperature changes. The analysis included sedimentological descriptions, physical properties, organic carbon and carbonate content, mineralogy and geochemical composition together with biological proxies including diatom and ostracod assemblages. A detailed pollen study enabled reconstruction of variations in vegetation cover, which were interpreted in the context of climate changes and human impact. Four distinct stages were recognized for the last 13,500 years: (1) a cold and dry episode that includes the Younger Dryas event (13,500–11,600 cal. year BP); (2) a humid and warmer period characterizing the onset of the Holocene (11,600–8,700 cal. year BP); (3) a tendency toward a drier climate during the middle Holocene (8,700–4,650 cal. year BP); and (4) a return to humid conditions following landscape modification by human activity (pastoral activities, deforestation) in the late Holocene (4,650–2,200 cal. year BP). Superimposed on relatively stable landscape conditions (e.g. maintenance of well established forests), the typical environmental variability of the southern European region is observed at this site.The Spanish Inter-Ministry Commission of Science and Technology (CICYT), the Spanish National Parks agency, the European Commission, the Spanish Ministry of Science, and the European Social Fund

Revealing the last 13,500 years of environmental history from the multiproxy record of a mountain lake (Lago Enol, northern Iberian Peninsula)

This is the author's accepted manuscript. The final publication is available at Springer via http://dx.doi.org/10.1007/s10933-009-9387-7.We present the Holocene sequence from Lago Enol (43°16′N, 4°59′W, 1,070 m a.s.l.), Cantabrian Mountains, northern Spain. A multiproxy analysis provided comprehensive information about regional humidity and temperature changes. The analysis included sedimentological descriptions, physical properties, organic carbon and carbonate content, mineralogy and geochemical composition together with biological proxies including diatom and ostracod assemblages. A detailed pollen study enabled reconstruction of variations in vegetation cover, which were interpreted in the context of climate changes and human impact. Four distinct stages were recognized for the last 13,500 years: (1) a cold and dry episode that includes the Younger Dryas event (13,500–11,600 cal. year BP); (2) a humid and warmer period characterizing the onset of the Holocene (11,600–8,700 cal. year BP); (3) a tendency toward a drier climate during the middle Holocene (8,700–4,650 cal. year BP); and (4) a return to humid conditions following landscape modification by human activity (pastoral activities, deforestation) in the late Holocene (4,650–2,200 cal. year BP). Superimposed on relatively stable landscape conditions (e.g. maintenance of well established forests), the typical environmental variability of the southern European region is observed at this site.The Spanish Inter-Ministry Commission of Science and Technology (CICYT), the Spanish National Parks agency, the European Commission, the Spanish Ministry of Science, and the European Social Fund