40Ar–39Ar dating of volcanogenic products from the AND-2A core (ANDRILL Southern McMurdo Sound Project, Antarctica): correlations with the Erebus Volcanic Province and implications for the age model of the core

The AND-2A drillcore (Antarctic Drilling Program—ANDRILL) was successfully completed in late 2007 on the Antarctic continental margin (Southern McMurdo Sound, Ross Sea) with the aim of tracking ice proximal to shallow marine environmental fluctuations and to document the 20-Ma evolution of the Erebus Volcanic Province. Lava clasts and tephra layers from the AND-2A drillcore were investigated from a petrographic and stratigraphic point of view and analyzed by the ⁴⁰Ar–³⁹Ar laser technique in order to constrain the age model of the core and to gain information on the style and nature of sediment deposition in the Victoria Land Basin since Early Miocene. Ten out of 17 samples yielded statistically robust ⁴⁰Ar–³⁹Ar ages, indicating that the AND-2A drillcore recovered ≤230 m of Middle Miocene (∼128–358 m below sea floor, ∼11.5–16.0 Ma) and >780 m of Early Miocene (∼358–1093 m below sea floor, ∼16.0–20.1 Ma). Results also highlight a nearly continuous stratigraphic record from at least 358 m below sea floor down hole, characterized by a mean sedimentation rate of ∼19 cm/ka, possible oscillations of no more than a few hundreds of ka and a break within ∼17.5–18.1 Ma. Comparison with available data from volcanic deposits on land, suggests that volcanic rocks within the AND-2A core were supplied from the south, possibly with source areas closer to the drill site for the upper core levels, and from 358 m below sea floor down hole, with the “proto-Mount Morning” as the main source.     

Thick self-standing bent crystals as optical elements for a Laue lens for applications in astrophysics

In this paper we report progresses in the realization of self-standing bent crystals, which are suitable as optical elements for Laue lenses, i.e. for optic to focus hard X-rays in the 100–1000 keV energy range. The curvature of the crystals is a key factor to enhance diffraction efficiency and energy bandpass for such an optic. In particular, two bent crystals featuring a thickness of 5 mm, made of Si and Ge respectively, were produced at the Sensor and Semiconductor Laboratory in Ferrara, Italy. The crystals were bent through the application of a carbon fibre composite. This proved to be a relatively low cost method for crystal bending, suitable for mass production. The manufactured samples were characterised via optical interferometry, and showed a fairly uniform curvature. Finally, the samples were tested exploiting hard X-ray diffraction at the ID11 facility of the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. A careful analysis of the experimental data highlighted that the samples feature large energy bandpass, wide geometrical acceptance for incoming hard X-rays, and high diffraction efficiency. We therefore conclude that such self-standing crystals are good candidates as Laue lens components for astrophysics applications.     

Removal of Lead, Copper, Zinc and Cadmium from Water Using Phosphate Rock

Removal of Pb2 ,Cu~(2 ),Zn~(2 )and Cd~(2 )from aqueous solutions by sorption on a natural phosphate rock(FAP)was investigated.The effects of the contact time and initial metal concentration were examined in the batch method.The percentage sorption of heavy metals from solution ranges generally between 50% and 99%.The amount of sorbed metal ions follows the order Cu>Pb>Cd>Zn. Heavy metal immobilization was attributed to both surface complexation of metal ions on the surface of FAP grains and partial dissolution and precipitation of a heavy metal-containing phosphate.The very low desorption ratio of heavy metals further supports the effectiveness of FAP as an alternative and low-cost material to remove toxic Pb~(2 ),Cu~(2 ),Zn~(2 )and Cd~(2 )from polluted waters.     

Testing a new rill flow resistance approach using the Water Erosion Prediction Project experimental database

In this paper, a recently theoretically deduced rill flow resistance equation, based on a power‐velocity profile, was tested using the Water Erosion Prediction Project database. This database includes measurements of flow velocity, water depth, cross section area, wetted perimeter, and bed slope that were made in rills shaped on experimental sites distributed across the continental United States. In particular, three different experimental conditions (only rainfall, only flow, and rain with flow) were examined, and for each condition, the theoretically based relationship for estimating the Γ function of the power velocity profile was calibrated. The results established that (a) the Darcy‐Weisbach friction factor can be accurately estimated using the proposed theoretical approach, and (b) the flow resistance increases with the effect of rainfall impact.     

Comparing Beerkan infiltration tests with rainfall simulation experiments for hydraulic characterization of a sandy‐loam soil

Saturated soil hydraulic conductivity, K _s , data collected by ponding infiltrometer methods and usual experimental procedures could be unusable for interpreting field hydrological processes and particularly rainfall infiltration. The K _s values determined by an infiltrometer experiment carried out by applying water at a relatively large distance from the soil surface could however be more appropriate to explain surface runoff generation phenomena during intense rainfall events. In this study, a link between rainfall simulation and ponding infiltrometer experiments was established for a sandy‐loam soil. The height of water pouring for the infiltrometer run was chosen, establishing a similarity between the gravitational potential energy of the applied water, E _p , and the rainfall kinetic energy, E _k . To test the soundness of this procedure, the soil was sampled with the Beerkan estimation of soil transfer parameters procedure of soil hydraulic characterization and two heights of water pouring (0.03 m, i.e., usual procedure, and 0.34 m, yielding E _p  = E _k ). Then, a comparison between experimental steady‐state infiltration rates, i _sR , measured with rainfall simulation experiments determining runoff production and K _s values for the two water pouring heights was carried out in order to discriminate between theoretically possible (i _sR  ≥ K _s ) and impossible (i _sR  < K _s ) situations. Physically possible K _s values were only obtained by applying water at a relatively large distance from the soil surface, because i _sR was equal to 20.0 mm h^?1 and K _s values were 146.2–163.9 and 15.2–18.7 mm h^?1 for a height of water pouring of 0.03 and 0.34 m, respectively. This result suggested the consistency between Beerkan runs with a high height of water pouring and rainfall simulator experiments. Soil compaction and mechanical aggregate breakdown were the most plausible physical mechanisms determining reduction of K _s with height. This study demonstrated that the height from which water is poured onto the soil surface is a key parameter in infiltrometer experiments and can be adapted to mimic the effect of high intensity rain on soil hydraulic properties.     

Clinopyroxene/liquid trace element partitioning in natural trachyte–trachyphonolite systems: insights from Campi Flegrei (southern Italy)

Trace element partition coefficients between clinopyroxenes and associated glassy matrix (^Cpx/L D) have been determined for 13 REE, HFSE^4+,5+, U, Th, Sr, Pb, Sc and V from combined LA-ICP-MS/EMP analyses in selected trachytes and trachyphonolites from Campi Flegrei. Composition of clinopyroxene and glass is pretty homogeneous in the trachyphonolites, pointing to an overall attainment of the equilibrium conditions. In trachytes, conversely, phases show some compositional heterogeneity (due to the presence of clinopyroxene xenocrysts) that requested a more careful petrographic and geochemical inspection of the samples to assess the equilibrium clinopyroxene composition. In the trachyte clinopyroxenes, REE are compatible from Nd to Lu (^Cpx/L D up to 2.9), like Y, Ti, Sc and V. The ^Cpx/L D for Eu is lower than those of the adjacent REE, highlighting Eu²⁺ contribution. High D values are also shown by U, Th, Pb, Zr, Hf, Nb and Ta relatively to basaltic and andesitic systems, whereas the D _Sr is roughly similar to that found for less evolved magmas. Trachyphonolites are characterized by an overall decrease of the ^Cpx/L D for highly-charged cations (with the exception of V), and by a slight increase of D _Sr. REE are still compatible from Nd to Lu (^Cpx/L D up to 2.1), like Ti, Y, Sc and V. This variation is also predicted for REE and Y by models based on the elastic strain theory, being consistent with the slightly lower polymerization degree estimated for the trachyphonolites. However, the observed ^Cpx/L D _(REE,Y) are matched by the modelled ones only considering very low T (≤825°C), which are believed unlikely. This mismatch cannot be attributed to effects induced by the water-rich composition of the trachyte–trachyphonolite suite, since they would lower the observed ^Cpx/L D _(REE,Y). Moreover, the anomalous inflections of measured ^Cpx/L D for HREE suggests some crystal-chemical control, such as the entrance of these elements in a site distinct from M2. It is concluded that the large ^Cpx/L D determined for trachytes and trachyphonolites are likely induced by hitherto unconstrained changes of the Z³⁺ activities related to the composition of melt and/or solid. All these considerations strongly highlight the importance of a direct characterization of trace element partitioning in natural samples from magmatic systems poorly characterized by experimental studies. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Spatial analysis of thickness variability applied to an Early Jurassic carbonate platform in the central Southern Alps (Italy): a tool to unravel syn‐sedimentary faulting

Early Jurassic syn‐sedimentary extensional tectonics in the central Southern Alps controlled patterns of deposition within the Calcari Grigi carbonate platform. We used variogram maps to gather model‐independent information on the spatial distribution of thicknesses of selected platform units and investigated whether major syn‐sedimentary faults outlined subsiding domains during platform growth. Thicknesses display a spatial organization that suggests that large fault belts, often coincident with exposed Jurassic extensional structures, transected large parts of the platform. The network of four fault systems (trending NNW–SSE and NE–SW) displays orthorhombic symmetry, suggesting non‐Andersonian faulting and a true triaxial strain field with N100°E maximum extension or transfer shear zones connecting major NNW–SSE‐trending extensional faults. In both cases, inherited structures of Permian to Triassic age may have played a primary role in Jurassic faulting. If confirmed throughout the South‐Alpine domain, this arrangement could shed new light on Early Jurassic rifting mechanisms in the Southern Alps.     

The 183-WSL fast rain rate retrieval algorithm: Part I: Retrieval design

The Water vapour Strong Lines at 183 GHz (183-WSL) fast retrieval method retrieves rain rates and classifies precipitation types for applications in nowcasting and weather monitoring. The retrieval scheme consists of two fast algorithms, over land and over ocean, that use the water vapour absorption lines at 183.31 GHz corresponding to the channels 3 (183.31 ± 1 GHz), 4 (183.31 ± 3 GHz) and 5 (183.31 ± 7 GHz) of the Advanced Microwave Sounding Unit module B (AMSU-B) and of the Microwave Humidity Sounder (MHS) flying on NOAA-15-18 and Metop-A satellite series, respectively.The method retrieves rain rates by exploiting the extinction of radiation due to rain drops following four subsequent steps. After ingesting the satellite data stream, the window channels at 89 and 150 GHz are used to compute scattering-based thresholds and the 183-WSLW module for rainfall area discrimination and precipitation type classification as stratiform or convective on the basis of the thresholds calculated for land/mixed and sea surfaces. The thresholds are based on the brightness temperature difference Δ_win = T_B89 ? T_B150 and are different over land (L) and over sea (S): cloud droplets and water vapour (Δ_win < 3 K L; Δ_win < 0 K S), stratiform rain (3 K < Δ_win < 10 K L; 0 K < Δ_win < 10 K S), and convective rain (Δ_win > 10 K L and S). The thresholds, initially empirically derived from observations, are corroborated by the simulations of the RTTOV radiative transfer model applied to 20000 ECMWF atmospheric profiles at midlatitudes and the use of data from the Nimrod radar network. A snow cover mask and a digital elevation model are used to eliminate false rain area attribution, especially over elevated terrain. A probability of detection logistic function is also applied in the transition region from no-rain to rain adjacent to the clouds to ensure continuity of the rainfall field. Finally, the last step is dedicated to the rain rate retrieval with the modules 183-WSLS (stratiform) and 183WSLC (convective), and the module 183-WSL for total rainfall intensity derivation.A comparison with rainfall retrievals from the Goddard Profiling (GPROF) TRMM 2A12 algorithm is done with good results on a stratiform and hurricane case studies. A comparison is also conducted with the MSG-based Precipitation Index (PI) and the Scattering Index (SI) for a convective-stratiform event showing good agreement with the 183-WSLC retrieval. A complete validation of the product is the subject of Part II of the paper.     

Rock magnetic,petrographic and dielectric characterization of prehistoric Amerindian potsherds from Venezuela

Rock magnetic, petrographic and dielectric analyses were carried out, in a number of archeological ceramic potsherds, in order to characterize the different manufacturing techniques used by Prehistoric Venezuelan Amerindian potters. Samples were excavated in 7 Venezuelan islands and ascribed to distinct cultural groups on purely stylistic grounds (i.e. Valencioide, Ocumaroide, Dabajuroide and Unknown). Mean coercivity values were determined through a direct signal analyses (DSA) applied to isothermal remanent magnetization (IRM) acquisition curves. Logarithmic plots of these mean coercivities are the best quantitative means to classify diverse ceramics. The mean coercivity values seem to group the samples according to the manufacturing development. These values also seem to discriminate the samples provenance, indeed, this plot displays a good grouping of data for samples presumably manufactured by the same culture but excavated at different locations. Thermomagnetic cycles supply helpful information about original ceramic firing conditions. The irreversibility parameter (IP) for thermomagnetic curves (heating and cooling), serves as an indicator of the amount of organic matter burnt during original pottery firing. The IP for a number of pottery samples from Venezuelan islands and mainland, with ages ranging between 300 BC to 1500 AD, might suggest a possible increasing trend in time towards the complete reversibility line of IP = 0. Most samples, independently of age and cultural group, have IP values that suggest that most open fires, used by primitive Venezuelan Amerindian potters, had enough ventilation and oxidizing atmospheres. A scatter plot of maximum current depolarization temperatures versus natural remanent magnetization (NRM) suggests a complex non-linear relationship between these two parameters most likely due to the fact that both, dielectric and rock magnetic data, are linked to pore-related features.     

Solute transport scales in an unsaturated stony soil

Solute transport parameters are known to be scale-dependent due mainly to the increasing scale of heterogeneities with transport distance and with the lateral extent of the transport field examined. Based on a transect solute transport experiment, in this paper we studied this scale dependence by distinguishing three different scales with different homogeneity degrees of the porous medium: the observation scale, transport scale and transect scale. The main objective was to extend the approach proposed by van Wesenbeeck and Kachanoski to evaluating the role of textural heterogeneities on the transition from the observation scale to the transport scale. The approach is based on the scale dependence of transport moments estimated from solute concentrations distributions. In our study, these moments were calculated starting from time normalized resident concentrations measured by time domain reflectometry (TDR) probes at three depths in 37 soil sites 1 m apart along a transect during a steady state transport experiment. The Generalized Transfer Function (GTF) was used to describe the evolution of apparent solute spreading along the soil profile at each observation site by analyzing the propagation of the moments of the concentration distributions. Spectral analysis was used to quantify the relationship between the solid phase heterogeneities (namely, texture and stones) and the scale dependence of the solute transport parameters. Coupling the two approaches allowed us to identify two different transport scales (around 4-5 m and 20 m, respectively) mainly induced by the spatial pattern of soil textural properties. The analysis showed that the larger transport scale is mainly determined by the skeleton pattern of variability. Our analysis showed that the organization in hierarchical levels of soil variability may have major effects on the differences between solute transport behavior at transport scale and transect scale, as the transect scale parameters will include information from different scales of heterogeneities.