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Microorganisms, particularly bacteria, inhabit all possible environments in the biosphere including subterranean ones. They play an important role in geological processes such as mineral precipitation and dissolution, and significantly influence biogeochemical cycles. At present, relatively few studies have focused on the active role of microorganisms, especially bacteria, in the formation of speleothems. Thus, the involvement of microbial activity in the formation of speleothems in caves is a geomicrobiological issue still to be solved. Today, the relationship between microorganisms and mineral fabrics and the role played by microorganisms in carbonate precipitation is unclear. The processes of carbonate deposit formation in caves offers an excellent scenario for research on biomineralization processes (from active microorganisms to their mineral deposits), because caves are protected environments where microbial fabrics can be preserved without extensive diagenetic modification or destruction. The new tendencies on geomicrobiological studies consist on applying different and multidisciplinary methodological approaches (petrology, geochemistry, microbiology, molecular biology) to (1) determine the role of the different microbial communities inhabiting the hypogean environments in the processes of mineral transformation, (2) identifying the physical and chemical properties of bioinduced crystalline phases, and (3) determine the environmental conditions, composition and texture of natural substrates (bioreceptivity) favouring or inhibiting the development of microbial communities.Los microorganismos, en particular las bacterias, habitan en todos los ambientes posibles de la biosfera incluidos los ambientes subterráneos. Desempeñan un papel importante en procesos geológicos tales como la precipitación y disolución mineral, e influyen notablemente sobre los ciclos biogeoquímicos de diferentes elementos. Hasta este momento, son relativamente pocos los estudios orientados a conocer el papel activo de los microorganismos, especialmente las bacterias, en la formación de espeleotemas, de manera que la implicación de la actividad microbiana en la precipitación y disolución mineral en ambientes kársticos es un tema aún sin resolver en geomicrobiología. Actualmente, no está del todo aclarada cuál es la interrelación entre los microorganismos y las fábricas minerales, ni el papel que juegan los microorganismos en la precipitación de carbonatos. Las cuevas son ambientes protegidos donde las fábricas microbianas pueden preservarse sin sufrir modificaciones diagenéticas importantes o destrucción, ofreciendo, por ello, un excelente entorno para estudiar los procesos de biomineralización (desde los propios microorganismos activos a sus depósitos minerales). Las nuevas tendencias en geomicrobiología se basan en la conjunción de diferentes metodologías (microclima, petrología, geoquímica, hidroquímica, microbiología, biología molecular) con un objetivo común: 1) determinar el papel de las diferentes comunidades microbianas que habitan los ambientes subterráneos en los procesos de transformación mineral; 2) identificar las propiedades físicas y químicas de las fases cristalinas bioinducidas, y 3) determinar las condiciones ambientales y las propiedades composicionales y texturales de los soportes rocosos naturales (biorreceptividad) que favorecen o inhiben el desarrollo de las comunidades microbianas.

There are summarized the data obtained after monitoring some microenvironmental parameters in the Pozalagua cave from 1st April 2001 to 1st july 2002. The singularity of this show cave is because the high amount of helictites type speleothems. Host rock, speleothems and infiltration waters have been analysed as well as the effect of the visits into the cave have been evaluated. It is stated that visits influence the temperature and CO2 levels inside the cave and the natural system need some time in recover from this changes. During massive visits increase in cave temperature is over the natural annual thermal oscillation. Management guidelines focused in visits schedule have been proposed in order to minimize the effects of the visits and to keep the cave microenvironment near the natural conditions.Se presentan los datos obtenidos tras el registro en continuo de diversos parámetros microambientales en la Cueva de Pozalagua (Vizcaya) durante el período del 1 de abril de 2001 al 1 de julio de 2002. La singularidad de esta cueva turística se debe a la alta presencia de espeleotemas tipo excéntricas o helictitas. Tras la caracterización de la roca encajante y diversos espeleotemas, así como de la hidroquímica de las aguas de infiltración que circulan por la misma, se ha evaluado el efecto que tienen las visitas turísticas en esta cavidad. Se constata que las visitas influyen claramente en la temperatura de la cavidad y en los niveles de CO2 de la misma, de lo que el sistema natural tarda tiempo en recuperarse. En períodos de visitas masivas se ha comprobado que el incremento de temperatura que se produce en la cavidad es superior a la oscilación térmica natural de la misma durante un ciclo anual. Se proponen medidas de gestión de la cavidad, principalmente enfocadas a optimizar el régimen de visitas, que minimicen el impacto de las mismas y que permitan mantener las condiciones microambientales de la cavidad cercanas a las condiciones originales naturales.

Moonmilk subaerial speleothems of Altamira Cave are constituted by a network of needle-fiber calcite crystals (NFC) and active microbial filaments. These recent deposits allow us the observation of the first evolution stages, as well as defining microclimatic and hydrochemical conditions of mineral precipitation. In previous works, the origin of the NFC has been determined being associated to fast mineral precipitation related with evaporation and criodesiccation processes. From our data, an evolutionary model has been proposed for this type of deposits. The stable microclimatic conditions of the cave, with air humidity close to saturation, lead us to conclude that their origin doesn't have to be related with these processes. Also it has been proven that the NFC of monocrystallyne rods type is generated by means of calcitization of microbial filaments. On the other hand, epitaxial cements and polycristalline chains are related with organic activity and inorganic processes in a confined aqueous environment developed inside the biofilm.Los espeleotemas subaéreos de tipo moonmilk de la Cueva de Altamira están constituidos fundamentalmente por un entramado de cristales aciculares calcíticos (needlefiber calcite, NFC) y filamentos microbianos activos. El carácter actual de los depósitos estudiados nos ha permitido observar los estadios iniciales de formación, así como las primeras fases de evolución de este tipo de agregados. En trabajos previos se establece el origen de los NFC asociado a rápida precipitación mineral debida a procesos de evaporación y criodesecación. Las estables condiciones microclimáticas de la cueva, con humedad del aire en saturación, nos permiten concluir que su origen no tiene que estar relacionado con dichos procesos. Asimismo se ha comprobado que los NFC de tipo varillas monocristalinas se generan mediante la calcitización de los filamentos microbianos. Los crecimientos epitaxiales y las cadenas policristalinas, en cambio, responden a fenómenos que pueden ser de carácter orgánico y/o inorgánico por precipitación química en un medio acuoso confinado dentro del biofilm.

Estado de las excavaciones y estudios en la Cueva de El Sidrón (PIloña, Asturias).

Trying to decipher how palaeoseismic activity has influenced the altitudinal disposition of interglacial deposits is one of the main challenges that must be achieved in order to quantify relative sea-level changes between consecutive highstands. Likewise, identifying palaeoseismic features in an area with low instrumental seismic activity can implement the seismic record and contribute to better seismic hazard knowledge. In this sense, Cope basin (SE Spain) becomes a reference basin to undertake this kind of analysis, firstly because of excellent outcrop conditions and secondly because the sea-level record is undoubtedly conditioned here by both effects: climatically driven changes and local and regional seismotectonics.

The spit bar of Calahonda (Granada), together with that one from Roquetas (Almería), constitutes one of the best examples in south-eastern Spain. Its development is associated to the different Holocene sea-level oscillations occurred since the last eustatic maximum. Progradation of these spit bars occurs under certain climatic conditions, which have repeated cyclically during Holocene times, giving place to different morphosedimentary units recognized along the whole southern peninsular littoral. In Calahonda, the main development of the spit bar is associated to the second progradation phase, which takes place since ca. 2,400 years.La flecha litoral de Calahonda (Granada) constituye, junto con la de Roquetas (Almería), uno de los mejores ejemplos del sureste peninsular. Su desarrollo está asociado a las distintas oscilaciones del nivel del mar ocurridas durante el Holoceno, una vez alcanzado el máximo eustático. En general, se ha visto que la progradación de estas flechas se produce en unas condiciones favorables determinadas, que se han repetido cíclicamente durante el Holoceno, y han quedado reflejadas como diferentes unidades morfosedimentarias, cuyo patrón de formación es reconocible en todo el sur peninsular. En Calahonda, el principal crecimiento de la flecha litoral está asociado a la segunda fase de progradación, desarrollada en los últimos 2.400 años.

Se presentan las intervenciones arqueo- lógicas en la Cueva del Sidrón y las investigaciones derivadas, durante las campañas de 2007 a 2012 las actuaciones se han organizado en los ámbitos de la Arqueología, Geología, Antropología, Paleogenética y Paleobiología. The archaeological interventions in Sidron Cave are presented and derivative research, bells during 2007-2012 performances are organized in the fields of Archaeology, Geology, Anthropology, Palaeogenetics and Paleobiology.

International audience

International audience; The age of Neanderthal remains and associated sediments from El Sidrón cave has been obtained through different dating methods (14CAMS, U/TH, OSL, ESR and AAR) and samples (charcoal debris, bone, tooth dentine, stalagmitic flowstone, carbonate-rich sediments, sedimentary quartz grains, tooth enamel and land snail shells). Detrital Th contamination rendered Th/U dating analyses of flowstone unreliable. Recent 14C contamination produced spurious age-values from charcoal samples as well as from inadequately pretreated tooth samples. Most consistent 14C dates are grouped into two series: one between 35 and 40 ka and the other between 48 and 49 ka. Most ESR and AAR samples yielded concordant ages, ranging between 39 and 45 ka; OSL dating results permitted adequate bracketing of the sedimentary layer that contained the human remains. Our results emphasize the value of multi-dating approaches for the establishment of reliable chronologies of human remains.

La Janda lake is located ¡rito a tectonic graben filled by Pleistocene and Holocene fluvio-marine sediments. Geophysical survey consisting on Electric-logs and seismic refraction profiles aimed to determining the thickness of Quaternary sediments infilling the graben. Nevertheless, the results are significantly distorted by a saline aquifer that occupies most of the sedimentary filling. In any case it is possible to identify an assymetric subsident area reaching up to 300 m depth, characterised by very low apparent resistivities (1.5-2.4 W/m). This thick geoelectrical unit can be preliminary subdivided into 3 different subunits here called A, 67, B2, characterised by resistivity differences. The shallow 4-6 m thick Unit A consists of a thin lacustrine and alluvial day and silts of Holocene age easily recognized in seismic refraction profiles and drill cores. Unit B can be separated in two subunits; Both are saturated in brackish or saline waters; B1 is a 20-40 m thick unit that thins northward and correspond to the Plio-Pleistocene, B2 is a slightly more resistive unit that extends from this depth to 352 m and corresponds to deeply weathered mio-pliocene sandstones. The upper part of Sub-unit 87 correspond to estuarine sands recorded in a previous core which deposition finishes at ca. 3810 cal BP. A sharp normal fault limits the southern part of La Janda assymetric graben

El estudio de un sondeo de 65 m en las marismas del Guadalquivir permite reconocer siete intervalos que reflejan cambios climáticos y eustáticos e intensa neotectónica durante tres periodos ¡nterglaciares (IS 71, 5 y i) y dos glaciares (IS 6-Riss-, IS 4, 3 y 2-WQrm). Se discute el valor de las 'vetas' como indicadores paleogeográficos

El estudio de un sondeo de 65 m en las marismas del Guadalquivir permite reconocer siete intervalos que reflejan cambios climáticos y eustáticos e intensa neotectónica durante tres periodos ¡nterglaciares (IS 71, 5 y i) y dos glaciares (IS 6-Riss-, IS 4, 3 y 2-WQrm). Se discute el valor de las 'vetas' como indicadores paleogeográficos

The interaction between global factors C'global" glacio-eustatic sea-level rise) and regional factors (tectonic trend, oceanographic factor) is analyzed in different areas of the Iberian and Canary Island littoral. Sea-level changes and climatic variations are stated for the Mediterranean and Atlantic littorals, with different tidal ranges and tectonic trends. Different stages can be envisaged in the coastal evolution of almost all the analyzed areas from the beginning of Holocene (10.000 BP): at ca. 7.000 BP (Flandrian maximum) with a change from open estuaries to aggradational processes (Cádiz Gulf, subsiding area), basal peat (Valencia Gulf, subsiding area) and development of microcliffs (Mediterranean uplifting areas). From 7.000 to 2,700 BP a first progradation phase with development of spit bars took place in the mediterranean uplifting areas, whilst in the atlantic subsiding one starts the aggradation processes in the formerly open estuaries, an also from ca.4,000 BP development of spit-bar system. A second progradation phase of the spit bars systems occurs between 2,400 and 500 BP both in Almería and Cádiz Gulf, where a change from aggradation to progradation takes place in the estuary environments, and with a change in the direction of longshore drift (Mediterranean) and prevailing winds (both areas) at ca.2,400 BP At ca. 1,200 BP a sudden paleogeographic change took place in estuary environments. From 500 BP up to now a marked increase of coastal progradation in all littorals is observed. Climatic interpretations led to correlate anticyclonlc conditions (as it happened during Little Ice Ages) with the growing of spit bar systems and progradation, while low pressure conditions (as during Medieval Warm Period) coincides with no progradation. In the Canary Islands, the development of storm ridges at ca. 3,500 BP can be correlated with an intensification of trade winds

Facies analysis and tridimensional relationships of the eolian and eolian-connected deposits of Pleistocene and Holocene age in Huelva allow to propose sedimentary models and discuss their temporal evolution and chronology

Sampling for dating coastal units and quantifying processes is only possible and rewarding after detailed mapping and morphosedimentary analysis. The study of Last and Present Interglacial deposits in the Iberian Peninsula reveals that there are short-term sea-level oscillations superimposed to longerterm periodicities. Although short-term periodicities, as those observed in spit-bar units, are vital for coastal management, longer-term changes should not be discarded

Facies analysis and tridimensional relationships of the eolian and eolian-connected deposits of Pleistocene and Holocene age in Huelva al/ow to propase sedimentary models and discuss their temporal evolution and chronology.