Estudio espectrográfico de la fracción ligera de las arenas del litoral catalán. Zona Blanes-Sitges

En este sector de costa se distinguen dos regiones mineralógicas y granulométricas. La arena de las playas situadas entre Barcelona y Blanes se forma por desintegración de los materiales de las montañas costeras. Los minerales pesados encontrados provierien de las rocas graníticas y de los afloramientos metamórficos de las citadas alineaciones. Al sur de Barcelona hay el delta del Llobregat cuya contribución es de poca importancia. Los minerales pesados que se encuentran son los típicos de las rocas metamórficas de su cuenca y la dolomita que procede de los niveles del infracretácico de Garraf. En las calizas mesozoicas de Garraf la arena se forma "in situ" y la dolomita es el mineral dominante.En el espectrograma realizado con la fracción ligera no fue posible encontrar ningún cambio en la concentración de los elementos pesados incluidos en ella, debido a su pequeña proporción. Tampoco fue posible encontrar ninguna relación entre los elementos radioactivos de la fracción ligera y la radiooactividad de esta parte de la costa catalana

Los arenales costeros de la isla de Menorca

The grain size of Menorca coastal sediment varies from very Fine to granule grade. The mean oscillates between 200-300p in the sand of Migjorn region and between 250-450p in the Tramuntana beaches, except for two cases in which [he grain size is bigger. The amount of carbonates of the sand examiiied is in some beaches very liigh, over 80 %. and the samples are very poor in heavy minerals. The heavy fraction is characterized by the highest values of opaque minerals. Dolomite and piroxenes are dominant among the heavy transparent minerals and rircon, tourmaline and garnet are always present in the :amples examined: biotite. nitile, epidote-zoisite and andalucite may also appear but only in some beache

Estudio espectrográfico de la fracción ligera de las arenas del litoral catalán. Zona Blanes-Sitges

En este sector de costa se distinguen dos regiones mineralógicas y granulométricas. La arena de las playas situadas entre Barcelona y Blanes se forma por desintegración de los materiales de las montañas costeras. Los minerales pesados encontrados provierien de las rocas graníticas y de los afloramientos metamórficos de las citadas alineaciones. Al sur de Barcelona hay el delta del Llobregat cuya contribución es de poca importancia. Los minerales pesados que se encuentran son los típicos de las rocas metamórficas de su cuenca y la dolomita que procede de los niveles del infracretácico de Garraf. En las calizas mesozoicas de Garraf la arena se forma "in situ" y la dolomita es el mineral dominante.En el espectrograma realizado con la fracción ligera no fue posible encontrar ningún cambio en la concentración de los elementos pesados incluidos en ella, debido a su pequeña proporción. Tampoco fue posible encontrar ninguna relación entre los elementos radioactivos de la fracción ligera y la radiooactividad de esta parte de la costa catalana

Estudio mineralógico de los arenales costeros de San Sebastián de La Gomera

The mineralogical study of sand frm the beach of San Sebastián de La Gomera has taken plaoe, applying khniques of granulometry, calcimetry, separation of the light and heavy fractions trough heavy liquids and difractometry of X rays. The percentage of heavy minerals excedes a0 per cent. The nlost important and abundant mineralogical species is the augite and the sediments lack quartz and the biaclasts are very scarce. The material which forms the sediment is completely val- canic in iBs origin and has been formed by the movement of the chasm which breaks away from Lomo Fragoso of which it is a terminal point, and by the costal abrasion

Utilización de la mineralogía de arenas en la interpretación paleoambiental de las llanuras aluviales costeras: El Empordà, NE de la Península Ibérica

Sand beach nourishment in NE Spain (Emporda basin)is characterized by the sand river supply and its redistribution due to dominant winds and longshore currents. The differences in heavy mineral composition of these sands allow us to propose a model for the origin of fossil and subfossil dunes in this basin

Utilización de la mineralogía de arenas en la interpretación paleoambiental de las llanuras aluviales costeras: El Empordà, NE de la Península Ibérica

Sand beach nourishment in NE Spain (Emporda basin)is characterized by the sand river supply and its redistribution due to dominant winds and longshore currents. The differences in heavy mineral composition of these sands allow us to propose a model for the origin of fossil and subfossil dunes in this basin

Mineralogía de los materiales detríticos de la Fm. Escucha (Albiense inferior) en el distrito minero de Teruel (sector Suroriental de la Cordillera Ibérica)

The present study focuses on the determination of the source areas of the Escucha Fm. (Albian) sediments in the Teruel Mining District (NE Spain). To this en4 we have carried out a detailed study of the heavy mineral fraction of the sandstone beds from this sedimentary unit at three stratigraphic successions at the Ariño-Oliete and Utrillas subbasins. The minerals found in the stratigraphic successions studied are in low proportions and a few mineral phases are present. Quartz is the dominant phase in the light mineral association, whereas potassium feldspars and plagioclase are in trace amounts. The opaque heavy minerals are hematite and goethite with minor amounts of pyrite. Finally, the transparent heavy minerals may be divided into the three following major associations: a) turmaline, zircon and rutile (resistant minerals); b) kyanite, staurolite and almandine (metamorphic association); and c) metamorphic mineral association from the Ctrillas sub-basin, characterised by very low heavy mineral proportions, and by the absence of one or various mineral phases from the association b. The flow directions from paleochannels and the absence of metarnorphic minerals in the sandstone levels of the upper unit of the Escucha Fm at the northern areas point to the "Platuforma del Ebro" as a possihle source area The minerals with this origin, with variable morphoscopy, could proceed from sedimentary recycling The metamorphic assemblage found in the southern areas may proceed from the "Macizo Castellano", where gneiss and mica-schists are present. It is not possible to precisse exactly the age of the source areas of the detrital sediments of the Escucha Fm This is due to the fact that these may have been different through the basin evolution, and also to the evidence of recycling processes The middle and lower units of the Escucha Fm at Ariño and Oliete, where the workable coa1 seams are present, show a metamorphic assemblage which demonstrate the Paleozoic age of the source lands Consequently, the Triassic units could also supply detrital minerals to the delta system of the Escucha Fm. These results are consistent with the hypothesis of the Triassic origin of the sulphur enrichment of the coals from the Ariño-Oliete area The recycling of detrital sediments from the Escucha Fm or a different source lana could account for the proteciion of the Utrillas sub-basin against the Triassic sulphate supply, and consequently for the lower sulphur content of the coals from this area.

Mineralogía de los materiales detríticos de la Fm. Escucha (Albiense inferior) en el distrito minero de Teruel (sector Suroriental de la Cordillera Ibérica)

The present study focuses on the determination of the source areas of the Escucha Fm. (Albian) sediments in the Teruel Mining District (NE Spain). To this en4 we have carried out a detailed study of the heavy mineral fraction of the sandstone beds from this sedimentary unit at three stratigraphic successions at the Ariño-Oliete and Utrillas subbasins. The minerals found in the stratigraphic successions studied are in low proportions and a few mineral phases are present. Quartz is the dominant phase in the light mineral association, whereas potassium feldspars and plagioclase are in trace amounts. The opaque heavy minerals are hematite and goethite with minor amounts of pyrite. Finally, the transparent heavy minerals may be divided into the three following major associations: a) turmaline, zircon and rutile (resistant minerals); b) kyanite, staurolite and almandine (metamorphic association); and c) metamorphic mineral association from the Ctrillas sub-basin, characterised by very low heavy mineral proportions, and by the absence of one or various mineral phases from the association b. The flow directions from paleochannels and the absence of metarnorphic minerals in the sandstone levels of the upper unit of the Escucha Fm at the northern areas point to the "Platuforma del Ebro" as a possihle source area The minerals with this origin, with variable morphoscopy, could proceed from sedimentary recycling The metamorphic assemblage found in the southern areas may proceed from the "Macizo Castellano", where gneiss and mica-schists are present. It is not possible to precisse exactly the age of the source areas of the detrital sediments of the Escucha Fm This is due to the fact that these may have been different through the basin evolution, and also to the evidence of recycling processes The middle and lower units of the Escucha Fm at Ariño and Oliete, where the workable coa1 seams are present, show a metamorphic assemblage which demonstrate the Paleozoic age of the source lands Consequently, the Triassic units could also supply detrital minerals to the delta system of the Escucha Fm. These results are consistent with the hypothesis of the Triassic origin of the sulphur enrichment of the coals from the Ariño-Oliete area The recycling of detrital sediments from the Escucha Fm or a different source lana could account for the proteciion of the Utrillas sub-basin against the Triassic sulphate supply, and consequently for the lower sulphur content of the coals from this area.