Morfoestructura y evolución del ramal N160 de la dorsal de la Cuenca Nor-Fidjiana (Pacífico sudoeste)

The North Fiji Basin is a complex marginal basin formed 10 Ma ago. It is located in the south-west Pacific, on the border of the Pacific and Indo-Australian crustal plates, between two subduction zones of opposed polarity: the New Hebndes trench, to the west, and the Tonga- Kennadec trench, to the east. The North Fiji Basin contains, on a small scale, many of the essential components of global plate tectonics: fracture zones, active spreading ridges, and triple junctions. In the center of the North Fiji Basin, there is a spreading axis constituted of three separate branches which can be individualized in accordance to their dominant directions. One of them, the N160 segment, is discussed in detail in this article, mainly based on recent data sets obtained during the Yokosuka 90 cruise (STARMER project, managed by the IFREMER, France, and the Science and Technology Agency, Japan). The aim of this cruise, carried out between 10th January and 6th February 1991, was the geological and geophysical study of the N160 section of the North Fiji Basin Ridge. Specific features of the N160 segment are pointed out which make it especially interesting with regard to the general knowledge and hypotheses about oceanic spreading ridges. As an example, the N160 segment shows an intermediate spreading rate of 5 cm/a and, at the same time, has a morphology which should be considered as being typical of slow-spreading centers. A succession of en échelon alternating rises and grabens exists between the two triple junctions limiting the segment, the northern one belonging to the Ridge-Ridge-Ridge (RRR) type, and the southern one to the Ridge-Ridge-Fracture Zone (RRF) type. The entire N160 segment is an extremely young morphostructural feature which, according to recorded magnetic stripes, began to be active less than one million years ago as a result of a rapid volcano-tectonic event

Insights into the structural evolution of the pre-Variscan rocks of the Eastern Pyrenees from La Molina quartz veins; constraints on chlorite and fluid inclusion thermometry

Quartz veins hosted in the infra and overlying series to the (Sardic) Upper Ordovician Unconformity provide new insights into the structural and thermal evolution of the pre-Variscan rocks of the Eastern Pyrenees. In the La Molina area (Canigó massif), two generations of metric quartz veins (V1 and V2) are distinguished by their distribution patterns and their relationships to the deformational macro, meso, and microstructures. P-T formation conditions are obtained by combining chlorite geothermometry and fluid inclusion microthermometry data. Discrepancy on formation temperature for chlorites located at different positions within the veins are discussed, concluding that veins grew in a low fluid/rock ratio regime. V1 veins can be related to the Late Ordovician syn-sedimentary faulting episode as revealed by their distribution patterns, formation mechanisms, and fluid-rock interactions. We propose an Alpine age for the V2 veins, based on their structure and the emplacement conditions of 318 ± 12°C and 2.4 ± 0.2kbar, with an estimated geothermal gradient of 34°C∙km-1 and a burial depth of ca. 9km. Results obtained here are compared with other quartz veins spread throughout the Paleozoic basement of the Eastern Pyrenees

The origin of large gypsum crystals in the Geode of Pulpí (Almería, Spain)

The Geode of Pulpí (Almería, Spain) is an ∼11 m3 ovoid cavity, the walls of which are covered with meter-sized idiomorphic and highly transparent gypsum (CaSO4●2H2O) crystals. We performed a thorough study based on field work, and petrographic and geochemical data collection, which aimed to reconstruct the geological history leading to the formation of this geode. The geode is hosted in mineralized Triassic carbonate rocks with a discontinuous mineral sequence from iron-carbonates and barite to celestine and finally gypsum (microcrystalline and selenite). Data from fluid inclusions show that barite precipitated above 100 °C, celestine at ∼70 °C, and gypsum below 25 °C. All δ34S sulfate phases fall between Triassic and Tertiary evaporite values. Barite and gypsum, either microcrystalline or large selenite crystals, show variable δ34S and δ18O compositions, whereas celestine and centimetric selenite gypsum have homogeneous values. We propose that the growth of the large selenite crystals in the Geode of Pulpí was the result of a self-feeding mechanism consisting of isovolumetric anhydrite replacement by gypsum at a temperature of 20 ± 5 °C, episodically contributed by a ripening process enhanced by temperature oscillations due to climatic change

Interpretando la Mina Rica (Pulpí, Almeria): estructura, mineralogía y geoquímica.

En este trabajo se presenta la estructura, mineralogía y geoquímica de la Mina Rica, un excelente ejemplo de la metalogenia del SE peninsular. Para ello se ha realizado la cartografía geológica detallada de las galerías, el estudio etrográfico de las zonas mineralizadas y no mineralizadas y el análisis isotópico de los sulfatos y sufuros

Unraveling the sulfate sources of (giant) gypsum crystals using gypsum isotope fractionation factors.

We combine newly determined isotope fractionation factors of gypsum precipitated in the laboratory with the isotopic compositions of natural anhydrite and gypsum to unravel the sulfate sources of the giant selenite crystals in the Naica mine (Chihuahua, Mexico). Gypsum was precipitated in the laboratory from CaSO4-NaCl-H2O solutions across a broad temperature range to establish the isotopic fractionation behavior of the sulfate molecule between the solid and dissolved phase. Oxygen isotopes show a significant fractionation dependence on temperature, with the solid phase more depleted in light isotopes with decreasing temperature. Sulfur isotopes display only a weak but similar dependence on temperature. At high salinity (4.5 M NaCl) no temperature dependence was found for the isotope composition. Based on this fractionation behavior, we attempt to elucidate the origin of the sulfate source(s) responsible for the formation of the (giant) gypsum crystals in the Naica mine. Detailed analysis of the isotopic composition of anhydrite, gypsum, and water samples strongly suggests that different types of anhydrite (of hypogenic and sedimentary origin) were dissolved to form these unique gypsum formations. The homogeneous isotopic composition of most gypsum crystals analyzed reveals an effective hydrodynamic mixing and a slow kinetics of precipitation fed by solutions of calcium sulfate from different anhydrite sources

Influence of supplementation with two specific inactivated dry yeast and grape-skin extract on the color and composition of red wine

Wines from grapes of Cabernet Sauvignon of the AOC Tarragona were elaborated with supplementation or not of two specific inactivated dry yeasts (Optired® and Optimum Red®; Lallemand Inc.) or with an experimental grape-skin extract. All the wines treated were significantly less astringent than the control wine because both inactivated dry yeast and the skin extract released polysaccharides which probably inhibit interactions between salivary proteins and tannins, and because their presence decrease the proportion of seed tannins and increase the proportion of skin tannins in the final wines

Evaluación de la composición y calidad del color de vinos tintos Tannat elaborados por maceración pre-fermentativa en caliente

Durante la vendimia 2016 se elaboraron vinos tintos Tannat por maceración pre-fermentativa en caliente (una hora de calentamiento a 60–70 ∘C seguido de una maceración fermentativa de 7 días) y maceración tradicional (maceración fermentativa de 7 días) con el objetivo de evaluar su concentración en compuestos fenólicos y color durante la conservación. Las vinificaciones se realizaron por triplicado en recipientes de 10 litros de capacidad. Se determinó la composición básica del vino, color, concentración de fenoles totales, antocianos, catequinas, proantocianidinas y los índices de ionización, copigmentados y PVPP. Los vinos con maceración pre-fermentativa en caliente presentaron mayor concentración de antocianos y taninos, mayor porcentaje de antocianos ionizados, co-pigmentados y condensados. Adicionalmente, presentaron mayor proporcion de delfinidina, petunidina y peonidina al descube. El calentamiento degrada las enzimas polifenoloxidasas por lo que estas formas antociánicas pudieron haber sido preservadas de la oxidación. Las concentraciones de las diferentes formas antociánicas disminuyeron durante la conservación de los vinos de ambos tratamientos, sin observarse diferencias en el perfil antocianico después de dos años. Los vinos elaborados por maceración pre-fermentativa en caliente presentaron mayor intensidad colorante durante todo el período de evaluación sugiriendo una mayor estabilidad del color

A role of mitochondrial complex II defects in genetic models of Huntington's disease expressing N-terminal fragments of mutant huntingtin.

Huntington's disease (HD) is a neurodegenerative disorder caused by an abnormal expansion of a CAG repeat encoding a polyglutamine tract in the huntingtin (Htt) protein. The mutation leads to neuronal death through mechanisms which are still unknown. One hypothesis is that mitochondrial defects may play a key role. In support of this, the activity of mitochondrial complex II (C-II) is preferentially reduced in the striatum of HD patients. Here, we studied C-II expression in different genetic models of HD expressing N-terminal fragments of mutant Htt (mHtt). Western blot analysis showed that the expression of the 30 kDa Iron-Sulfur (Ip) subunit of C-II was significantly reduced in the striatum of the R6/1 transgenic mice, while the levels of the FAD containing catalytic 70 kDa subunit (Fp) were not significantly changed. Blue native gel analysis showed that the assembly of C-II in mitochondria was altered early in N171-82Q transgenic mice. Early loco-regional reduction in C-II activity and Ip protein expression was also demonstrated in a rat model of HD using intrastriatal injection of lentiviral vectors encoding mHtt. Infection of the rat striatum with a lentiviral vector coding the C-II Ip or Fp subunits induced a significant overexpression of these proteins that led to significant neuroprotection of striatal neurons against mHtt neurotoxicity. These results obtained in vivo support the hypothesis that structural and functional alterations of C-II induced by mHtt may play a critical role in the degeneration of striatal neurons in HD and that mitochondrial-targeted therapies may be useful in its treatment