Eoalpine tectonics of the Eastern Alps: implications from the evolution of monometamorphic Austroalpine units (Schneeberg and Radenthein Complex)

Monometamorphic metasediments of Paleozoic or Mesozoic age constituting Schneeberg and Radenthein Complex experienced coherent deformation and metamorphism during Late Cretaceous times. Both complexes are part of the Eoalpine high-pressure wedge that formed an intracontinental suture and occur between the polymetamorphosed Ötztal–Bundschuh nappe system on top and the Texel–Millstatt Complex below. During Eoalpine orogeny Schneeberg and Radenthein Complexes were south-dipping and they experienced a common tectonometamorphic history from ca. 115 Ma onwards until unroofing of the Tauern Window in Miocene times. This evolution is subdivided into four distinct tectonometamorphic phases. Deformation stage D1 is characterized by WNW-directed shearing at high temperature conditions (550–600°C) and related to the initial exhumation of the high-pressure wedge. D2 and D3 are largely coaxial and evolved during high- to medium-temperature conditions (ca. 450 to ≥550°C). These stages are related to advanced exhumation and associated with large-scale folding of the high-pressure wedge including the Ötztal-Bundschuh nappe system above and the Texel–Millstatt Complex below. For the area west of the Tauern Window, F2/F3 fold interference results in the formation of large-scale sheath-folds in the frontal part of the nappe stack (formerly called “Schlingentektonik” by previous authors). Earlier thrusts were reactivated during Late Cretaceous normal faulting at the base of the Ötztal–Bundschuh nappe system and its cover. Deformation stage D4 is of Oligo-Miocene age and accounted for tilting of individual basement blocks along large-scale strike-slip shear zones. This tilting phase resulted from indentation of the Southern Alps accompanied by the formation of the Tauern Window.     

Environmental Determinants of Emergent Macrophyte Vegetation in Pacific Northwest Estuarine Tidal Wetlands

We investigated whether within wetland environmental conditions or surrounding land cover measured at multiple scales were more influential in structuring regional vegetation patterns in estuarine tidal wetlands in the Pacific Northwest, USA. Surrounding land cover was characterized at the 100, 250, and 1,000 m, and watershed buffer scales. Vegetation communities were characterized by high species richness, lack of monotypic zonation, and paucity of invasive species. The number of species per site ranged between 4 and 20 (mean?±?standard deviation?=?10.2?±?3.1). Sites supported a high richness (mean richness of native species 8.7?±?2.8) and abundance of native macrophytes (mean relative abundance 85 %?±?19 %). Vegetation assemblages were dominated by a mix of grasses, sedges, and herbs with Sarcocornia pacifica and Distichlis spicata being common at sites in the oceanic zone of the estuary and Carex lyngbyei and Agrostis stolonifera being common at the fresher sites throughout the study area. The vegetation community was most strongly correlated with salinity and land cover within close proximity to the study site and less so with land cover variables at the watershed scale. Total species richness and richness of native species were negatively correlated with the amount of wetland in the buffer at all scales, while abundance of invasive species was significantly correlated to within wetland factors, including salinity and dissolved phosphorus concentrations. Landscape factors related to anthropogenic disturbances were only important at the 100-m buffer scale, with anthropogenic disturbances further from the wetland not being influential in shaping the vegetation assemblage. Our research suggests that the traditional paradigms of tidal wetland vegetation structure and environmental determinants developed in east coast US tidal wetlands might not hold true for Pacific Northwest wetlands due to their unique chemical and physical factors, necessitating further detailed study of these systems.     

Flux and dispersion of gases from the “Drachenschlund” hydrothermal vent at 8°18' S, 13°30' W on the Mid-Atlantic Ridge

Hydrothermal emission of mantle helium appears to be directly related to magma production rate, but other processes can generate methane and hydrogen on mid-ocean ridges. In an on-going effort to characterize these processes in the South Atlantic, the flux and distribution of these gases were investigated in the vicinity of a powerful black smoker recently discovered at 8°17.9' S, 13°30.4' W. The vent lies on the shoulder of an oblique offset in the Mid-Atlantic Ridge and discharges high concentrations of methane and hydrogen. Measurements during expeditions in 2004 and 2006 show that the ratio of CH₄ to ³He in the neutrally buoyant plume is quite high, 4 × 10⁸. The CTD stations were accompanied by velocity measurements with lowered acoustic Doppler current profilers (LADCP), and from these data we estimate the methane transport to have been 0.5 mol s^− 1 in a WSW-trending plume that seems to develop during the ebb tidal phase. This transport is an order of magnitude greater than the source of CH₄ calculated from its concentration in the vent fluid and the rise height of the plume. From this range of methane fluxes, the source of ³He is estimated to be between 0.14 and 1.2 nmol s^− 1. In either case, the ³He source is significantly lower than expected from the spreading rate of the Mid-Atlantic Ridge. From the inventory of methane in the rift valley adjacent to the vent, it appears that the average specific rate of oxidation is 2.6 to 23 yr^− 1, corresponding to a turnover time between 140 and 16 days. Vertical profiles of methane in the surrounding region often exhibited Gaussian-like distributions, and the variances appear to increase with distance from the vent. Using a Gaussian plume model, we obtained a range of vertical eddy diffusivities between 0.009 and 0.08 m²m² s^− 1. These high values may be due to tidally driven internal waves across the promontory on which the vent is located.     

Structural features of Panarea volcano in the frame of the Aeolian Arc (Italy): Implications for the 2002–2003 unrest

Panarea, characterized by gas unrest in 2002–2003, is the volcanic island with the least constrained structure in the eastern-central Aeolian Arc (Italy). Based on structural measurements, we define here its deformation pattern relative to the Arc. The main deformations are subvertical extension fractures (63% of data), normal faults (25%) and dikes (12%). The mean orientation of the extension fractures and faults is N38°E, with a mean opening direction of N135° ± 8°, implying extension with a moderate component of dextral shear. These data, matched with those available for Stromboli volcano (pure opening) and Vulcano, Lipari and Salina volcanoes (predominant dextral motions) along the eastern-central Arc, suggest a progressive westward rotation of the extension direction and an increase in the dextral shear. The dextral shear turns into compression in the western arc. The recent unrest at Panarea, coeval to that of nearby Stromboli, may also be explained by the structural context, as both volcanoes lie along the portion of the Arc subject to extension.     

The Evolution of the Interstellar Medium over Cosmic Time

C23 UV spectroscopy of the PG1159-type star NGC7094 C26 Variations of the radio synchrotron spectral index in the interstellar medium of M33 C38 Angular Momentum Evolution of Young Brown Dwarfs and Low Mass Stars C48 The radio halo of the nearby starburst galaxy NGC 253 C95 Signatures of early metal enrichment in Damped-Lyman Alpha systems C113 CO 4 → 3 and [CI] 1 → 0 in the centers of NGC4945 and Circinus C115 Ratio of atomic and molecular gas and gravitational stabilty in the disk of M51 C130 The Interstellar Mediumat Early Cosmic Times: Molecular Gas in Distant Quasar Host Galaxies C188 Probing the interstellar medium in distant galaxies with SPICA/ESI C191 The evolution of spectral energy distributions of galaxies over cosmic times C197 Observations of 60Fe in the Galaxy with INTEGRAL/SPI C204 Evolution of Interstellar Clouds in a hot Gas Environment C205 The effect of clouds in a galactic wind on the evolution of gas-rich dwarf galaxies C206 Energy and element deposit into the interstellar medium during the lives of massive stars C209 The distribution and kinematics of massive stars in the inner Galaxy mapped with SPI/INTEGRAL 26Al 1.8 MeV line observations C213 PDR modelling of the Galactic FIR line emission C239 Towards a complete picture of the molecular ISM in local Luminous Infrared Galaxies: first results from the JCMT/IRAM line survey C242 The Search for the Very High-redshift Tail of Submillimeter Galaxies     

上部地壳的流体作用与大理岩的低温塑性

本文应用光学显微镜、透射电子显微镜和阴极发光显微镜系统研究了Ｗａｔｅｒｂｅｒｇ断层带（纳米比亚）内粗晶大理岩中发育的构造岩,宏观碎裂结构与微观糜棱装结构是断层构造岩的主要特点。巨大的孪形碎屑与弥漫的细小粒质形成了鲜明的反差,广泛发育的压溶颖合线与多阶段方解石细脉遍布构造带不同部位,ＴＥＭ亚微粒粒度具有简单的峰值分布（～０．３～０．４μｍ）,但动态重结晶颗粒的粒度却具有较大的变化范围（０．１～３．０     

Hydrogeochemical prospecting for porphyry copper deposits in the tropical-marine climate of Puerto Rico

A hydrogeochemical survey utilizing waters from streams and springs was conducted in the area of two known porphyry copper deposits in the tropical-marine climate of westcentral Puerto Rico. The most important pathfinder for regional hydrogeochemical surveys is sulfate which reflects the associated pyrite mineralization. Because of increased mobility due to intense chemical weathering and the low pH environment, dissolved copper can also be used as a pathfinder for regional surveys and has the advantage of distinguishing barren pyrite from pyrite associated with copper mineralization. For follow-up surveys, the most important pathfinders are copper, sulfate, pH, zinc, and fluoride. High concentrations of dissolved copper and moderate concentrations of sulfate is a diagnostic indication of nearby sources of copper minerals.An understanding of the geochemical processes taking place in the streambeds and the weathering environment, such as the precipitation of secondary copper minerals, contributes to the interpretation of the geochemical data and the selection of the most favorable areas for further exploration.     

Hydrological response to climate change in a glacierized catchment in the Himalayas

The analysis of climate change impact on the hydrology of high altitude glacierized catchments in the Himalayas is complex due to the high variability in climate, lack of data, large uncertainties in climate change projection and uncertainty about the response of glaciers. Therefore a high resolution combined cryospheric hydrological model was developed and calibrated that explicitly simulates glacier evolution and all major hydrological processes. The model was used to assess the future development of the glaciers and the runoff using an ensemble of downscaled climate model data in the Langtang catchment in Nepal. The analysis shows that both temperature and precipitation are projected to increase which results in a steady decline of the glacier area. The river flow is projected to increase significantly due to the increased precipitation and ice melt and the transition towards a rain river. Rain runoff and base flow will increase at the expense of glacier runoff. However, as the melt water peak coincides with the monsoon peak, no shifts in the hydrograph are expected.