Sistemas lacustres paleógenos de Mallorca (Mediterráneo Occidental)

Dos importantes sistemas lacustres-palustres se desarrollaron durante el Paleógeno en las Baleares. En el primero de ellos, de edad Bartoniense (Eoceno medio), se formó una importante acumulación de sedimentos carbonatados biogénicos y organógenos (lignitos). La organización megasecuencial de las sucesiones lacustres registra la siguiente evolución del sistema: 1) implantación de los medios lacustres, 2) expansión y relativa profundización, 3) colmatación por progradación de los depósitos de las zonas marginales del sistema sobre las internas y 4) etapa final, dominantemente agradante, con un pronunciado equilibrio entre las tasas de sedimentación y subsidencia. El segundo sistema, de edad oligocena (Estampiense superior- Chatiense), esta constituido por una asociación de depósitos lacustres y palustres relacionados con facies distales de un sistema aluvial. Por ello, el aporte de materiales detriticos finos al sistema lacustre jugó un papel primordial; aunque en las zonas mis protegidas de las cubetas lacustres, la acumulación de carbonatos biogénicos y la de maicriaorginica fue también importante. Su evolución megasecuencial sugiere las siguientes fases: 1) implantación en zonas terminalesdistales del sistema aluvial, 2) expansión e implantación de depocentros carbonatados, y 3) colmatación final relacionada con la progradación de las zonas terminales del sistema aluvial. Ambos  sistemas lacustres indican el desarrollo de etapas de estratificación permanente u ocasional de la columna de agua. Ello permitió  lapreservación de materia orgánica derivada de macrófitos superiores y de organismos algales y bacterias

Paleoflora del Oligoceno de Mallorca

Abstract not availabl

Estudio paleobotánico del Paleógeno de Peguera:

Abstract not availabl

Estructura y relleno sedimentario de la semifosa neógena de Vilanova (Garraf, Barcelona)

A joint study involving geological mapping, well subsurface data and gravity modelling has been carried out in the Vilanova half graben in order to define the substralum structure and the character of the sedimentary in fill.The half graben is oriented following a regional ENE-WSW fault direction. Its structure is controlled by normal faults along the NW boundary and by an unconformity in the SE basin boundary. A perpendicular to the main direction fault system, configurate a block shaped hasement. From the residual gravity map a 3D density model, constrained with the depths infered kom bore oles, has been obtained. The sedimentary infill has been divided in four litostratigraphic units. One of them constitutes a marginal complex associated and genetically related with the main faults that bound the basin. The otber three units show a vertical evolution from continental alluvial environrnent at the bottom to marine (littoral and restricted shelf-bay) at tbe top.The paleomastological data allow ps to attribute to the autcropping sedimentary infill a Serravallian age. Nevertheless, an Aquitanian-Early Burdigalian age to the basal conglomeratic unit can't be definitively rejected

VISIR-VLT high resolution study of the extended emission of four obscured post-AGB candidates

The onset of the asymmetry of planetary nebulae (PNe) is expected to occur during the late Asymptotic Giant Branch (AGB) and early post-AGB phases of low- and intermediate-mass stars. Among all post-AGB objects, the most heavily obscured ones might have escaped the selection criteria of previous studies detecting extreme axysimmetric structures in young PNe. Since the most heavily obscured post-AGB sources can be expected to descend from the most massive PN progenitors, these should exhibit clear asymmetric morphologies. We have obtained VISIR-VLT mid-IR images of four heavily obscured post-AGB objects barely resolved in previous Spitzer IRAC observations to analyze their morphology and physical conditions across the mid-IR. The VISIR-VLT images have been deconvolved, flux calibrated, and used to construct RGB composite pictures as well as color and optical depth maps that allow us to study the morphology and physical properties of the extended emission of these sources. We have detected extended emission from the four objects in our sample and resolved it into several structural components that are greatly enhanced in the temperature and optical depth maps. They reveal the presence of asymmetry in three young PNe (IRAS 15534-5422, IRAS 17009-4154, and IRAS 18454+0001), where the asymmetries can be associated with dusty torii and slightly bipolar outflows. The fourth source (IRAS 18229-1127), a possible post-AGB star, is better described as a rhomboidal detached shell. The heavily obscured sources in our sample do not show extreme axisymmetric morphologies. This is at odds with the expectation of highly asymmetrical morphologies in post-AGB sources descending from massive PN progenitors. The sources presented in this paper may be sampling critical early phases in the evolution of massive PN progenitors, before extreme asymmetries develop.Comment: 9 pages, 4 figure

Icnología de vertebrados de la facies Buntsandstein de Mallorca

Se describen, por primera vez en Mallorca, hasta cinco tipos diferentes de icnitas y pistas de vertebrados continentales dentro de las facies  cuarzoareniticas y limosas rojas de la facies Buntsandstein del Triásico inferio

Extended X-ray emission from the classic nova DQ Her -- On the possible presence of a magnetized jet

We present an analysis of archival Chandra and XMM-Newton observations of the magnetically-active cataclysmic variable DQ Her and the shell around it ejected in a nova event in 1934. A careful revision of the Chandra observations confirms previous claims on the presence of extended X-ray emission around DQ Her and reveals that it actually corresponds to a bipolar jet-like structure extending $\simeq$32$''$ along a direction from NE to SW. Therefore, this X-ray emission extends beyond the optical nova shell and is perpendicular to its major axis. The XMM-Newton observations confirm the presence of the extended X-ray emission detected by Chandra, suggesting the additional presence of a diffuse X-ray emission from a hot bubble filling the nova shell. This hot bubble was very likely produced by the explosion that created the nebular shell detected in optical images. The bipolar feature can be modelled by the combination of an optically thin plasma emission component with temperature $T\approx2\times10^{6}$ K and a power law component with a photon index of $\Gamma=1.1\pm0.9$. Its X-ray luminosity in the 0.3 - 5 keV energy range is $L_\mathrm{X}=(2.1\pm1.3)\times10^{29}$ erg s$^{-1}$, for an electron density $n_\mathrm{e}\approx2$ cm$^{-3}$ and a mass $m_\mathrm{X}\approx 3\times10^{-6}$ M$_{\odot}$. We suggest that the X-ray bipolar structure in DQ Her is a jet and interpret its non-thermal X-ray emission in terms of a magnetized jet.Comment: 8 pages, 4 figures, 1 table; accepted to MNRA

Fauna coralina de las plataformas mixtas del Paleógeno de las Baleares

Abstract not availabl