Landslide complex in the northern part of the Silesian Beskydy Mountains (Czech Republic)

The study brings new information concerning a large slope deformation in the northern part of the Silesian Beskydy Mountains in the territory of the Czech Republic. The studied area is a large-scale transformation of the forefront of a flysch nappe formed especially by rigid sandstones upon a plastic underlying nappe. As a consequence of the vertical contact of mechanically different formations and depositing conditions of rocks and tectonics on the nappe forefront, several generations of deep-seated slope deformations occurred accompanied by shallow landslides in the historic period. Structural measurement and geophysical sounding proved prevailing lateral spreading in the upper parts of the slopes as well as the occurrence of rotational landslides whose landslide scarps overlap with the line of overthrust of the Godula Nappe on the Těšín Nappe. Radiocarbon dating determined the period of the occurrence of rotational landslides as falling into the Subboreal up to Subatlantic.     

The performance of the empirical models on industrial hydrocyclone design

Many empirical models have been used widely for designing hydrocyclones in industry. These empirical models consist of a set of design equations. Most of the design equations are based on the correlations obtained experimentally, using dimensionless similarity numbers. These equations have their limitations due to the specific systems used for model development. Therefore, in many cases, they cannot be used with confidence to predict the design of an individual separator, or the overall plant configuration that is required to meet different user requirements. A modified version of the existing design equations presented by previous researchers was developed. The design equations, describing four fundamental parameters: pressure drop, flow recovery to underflow, corrected cut size and classification function, were modified by fitting with set of experimental data to obtain the system-specific constant parameters. These modified design equations were then called, the fine-tuned design equations. Four sets of fine-tuned design equations describing all the fundamental parameters were constructed and used to predict the separation performance of many hydrocyclone operational systems at the Dow Chemical Company, Texas, USA. The performance of these equations is evaluated, and the limitations of their use are discussed, thus providing useful insights into hydrocyclone design.     

National forest carbon inventories: policy needs and assessment capacity

Previous research has identified the importance of the role of land cover in the global carbon cycle. In particular, forests have been identified as a significant carbon sink that can mitigate the rate of global climate change. Policy makers are faced with complex and difficult challenges in getting timely and useful information in monitoring global forest resources. Recent advances in the tools and methods of forest carbon accounting have produced new, innovative approaches to forest-based carbon inventories. But it is important as new tools are developed that scientists understand the needs of policy makers and that policy makers understand the capabilities and limitations of forest inventory methods. This paper explores four different policy applications that rely, or could benefit from, national carbon inventories. The goal is to help build a bridge between the communities of climate policy makers and scientists specialized in forest carbon inventories. To this end, we pursue three specific objectives: First we provide an overview for policy makers about approaches to forest carbon inventories, paying particular attention to the contributions of remote sensing technologies. Second, we outline the issues particularly relevant to forest inventory scientists who are interested in responding to public policy needs. We then discuss the tradeoffs between information cost, accuracy, precision, transparency and timeliness that need to be balanced in long-term monitoring of forest carbon. Finally, the article concludes with a series of observations and recommendations for the implementation of forest carbon inventories as increasingly central components of global climate change policy.     

Assessment of interpolated ERA-40 reanalysis temperature and precipitation against observations of the Balkan Peninsula

Due to their ready availability and temporal and spatial consistency, reanalysis data are widely used within the climate community. Nevertheless, higher spatial resolutions are often required and statistical interpolation techniques are applied to increase the data resolution. This work aims to derive a set of high spatial resolution data through three-dimensional interpolation of daily temperature and precipitation. Thin plate spline interpolation has been chosen and used to interpolate ERA-40 temperature and precipitation from a coarse grid (110 km) into a finer one of 1-km spatial resolution. The study evaluates the method by comparing the simulated variables with available in situ meteorological measurements. The chosen stations are distributed over the study region and, most importantly, contain information from a range of altitudes. The results indicate that accounting for the topography in the interpolation process improves the comparisons, with the biggest improvements being evident in the most mountainous areas. The method is found to be better in estimating temperature than precipitation fields. Moreover, the method performs better for maximum temperature in high altitudes and for minimum temperature in low altitudes.     

Mechanisms of fine extinction band development in vein quartz: new insights from correlative light and electron microscopy

Fine extinction bands (FEBs) (also known as deformation lamellae) visible with polarized light microscopy in quartz consist of a range of nanostructures, inferring different formation processes. Previous transmission electron microscopy studies have shown that most FEB nanostructures in naturally deformed quartz are elongated subgrains formed by recovery of dislocation slip bands. Here we show that three types of FEB nanostructure occur in naturally deformed vein quartz from the low-grade metamorphic High-Ardenne slate belt (Belgium). Prismatic oriented FEBs are defined by bands of dislocation walls. Dauphiné twin boundaries present along the FEB boundaries probably formed after FEB formation. In an example of two sub-rhombohedral oriented FEBs, developed as two sets in one grain, the finer FEB set consists of elongated subgrains, similar to FEBs described in previous transmission electron microscopy studies. The second wider FEB set consists of bands with different dislocation density and fluid-inclusion content. The wider FEB set is interpreted as bands with different plastic strain associated with the primary growth banding of the vein quartz grain. The nanometre-scale fluid inclusions are interpreted to have formed from structurally bounded hydroxyl groups that moreover facilitated formation of the elongate subgrains. Larger fluid inclusions aligned along FEBs are explained by fluid-inclusion redistribution along dislocation cores. The prismatic FEB nanostructure and the relation between FEBs and growth bands have not been recognized before, although related structures have been reported in experimentally deformed quartz.     

Siliceous Cementation of Chlorite-Coated Grains in the Permian Sandstone Gas Reservoirs, Ordos Basin

<正>Objective It has long been controversial that whether authigenic chlorite coatings in sandstone reservoirs can prevent precipitation of siliceous cements.It is commonly believed that chlorite coatings(also called chlorite films,chlorite linings,or chlorite rims)may prevent quartz overgrowth,and thus help the preservation of original pores in sandstone reservoirs.Recently,however,this assumption has been challenged by reservoir geologists.This dispute cannot be solved by mere analysis of thin sections,nor by chemical equations and diagenesis analysis.The main objective of the present contribution is to shed light on this     

Trace Element Determination of Single Fluid Inclusions in Quartz by Laser Ablation ICP-MS

Single fluid inclusions in quartz from a Pb-Zn-Ag carbonate replacement deposit were selected for trace element determination by laser ablation ICP-MS. Spikes in element intensities were noted between first breached fluids versus subsequent analyses, suggesting that accurate element concentrations may not be determined in smaller fluid inclusions when only one analysis is obtained before the fluid is exhausted. Elemental concentrations in the fluid inclusions were determined by external standardisation using solutions sealed in microcapillary tubes. Standards and single natural inclusion analyses give repeatabilities (%RSD) of ˜ 20% for Rb and Sr. Rubidium and strontium concentrations range from 0.56-5.07 μg ml^-1 and 1.12-27.4 μg ml^-1, respectively, whereas Zn and Ag are below detection limits (< 10 ng ml^-1). The results suggest that nearly all Zn and Ag are removed by the time hydrothermal fluids precipitate gangue minerals.     

Carbonatite melt–CO2 fluid inclusions in mantle xenoliths from Tenerife, Canary Islands: a story of trapping, immiscibility and fluid–rock interaction in the upper mantle

Three types of fluid inclusions have been identified in olivine porphyroclasts in the spinel harzburgite and lherzolite xenoliths from Tenerife: pure CO₂ (Type A); carbonate-rich CO₂–SO₂ mixtures (Type B); and polyphase inclusions dominated by silicate glass±fluid±sp±silicate±sulfide±carbonate (Type C). Type A inclusions commonly exhibit a “coating” (a few microns thick) consisting of an aggregate of a platy, hydrous Mg–Fe–Si phase, most likely talc, together with very small amounts of halite, dolomite and other phases. Larger crystals (e.g. (Na,K)Cl, dolomite, spinel, sulfide and phlogopite) may be found on either side of the “coating”, towards the wall of the host mineral or towards the inclusion center. These different fluids were formed through the immiscible separations and fluid–wall-rock reactions from a common, volatile-rich, siliceous, alkaline carbonatite melt infiltrating the upper mantle beneath the Tenerife. First, the original siliceous carbonatite melt is separated from a mixed CO₂–H₂O–NaCl fluid and a silicate/silicocarbonatite melt (preserved in Type A inclusions). The reaction of the carbonaceous silicate melt with the wall-rock minerals gave rise to large poikilitic orthopyroxene and clinopyroxene grains, and smaller neoblasts. During the metasomatic processes, the consumption of the silicate part of the melt produced carbonate-enriched Type B CO₂–SO₂ fluids which were trapped in exsolved orthopyroxene porphyroclasts. At the later stages, the interstitial silicate/silicocarbonatite fluids were trapped as Type C inclusions. At a temperature above 650 °C, the mixed CO₂–H₂O–NaCl fluid inside the Type A inclusions were separated into CO₂-rich fluid and H₂O–NaCl brine. At T<650 °C, the residual silicate melt reacted with the host olivine, forming a reaction rim or “coating” along the inclusion walls consisting of talc (or possibly serpentine) together with minute crystals of NaCl, KCl, carbonates and sulfides, leaving a residual CO₂ fluid. The homogenization temperatures of +2 to +25 °C obtained from the Type A CO₂ inclusions reflect the densities of the residual CO₂ after its reactions with the olivine host, and are unrelated to the initial fluid density or the external pressure at the time of trapping. The latter are restricted by the estimated crystallization temperatures of 1000–1200 °C, and the spinel lherzolite phase assemblage of the xenolith, which is 0.7–1.7 GPa.