Permafrost occurrence during the Last Permafrost Maximum in the Western Carpathian Mountains of Slovakia as inferred from cryogenic cave carbonate

Coarse crystalline cryogenic cave carbonate (CCC) forms during the slow freezing of standing water pools and represents indirect proof of freezing temperature in the past. The dating by U‐series of CCC deposits from nine caves in the Western Carpathians Mountains of Slovakia suggests that freezing conditions, and possible permafrost conditions, occurred during the Last Permafrost Maximum (LPM, c. 20–18 ka BP). The CCC deposits occur in caves at elevations of between 800 and 1800 m a.s.l. They point to widespread alpine permafrost, the lower limit of discontinuous/sporadic permafrost being approximately 800 m a.s.l. The thickness of permafrost probably varied between 30 and 180 m. In the Vysoké Tatry Mountains at altitudes of ～1800 m a.s.l., one occurrence of CCC suggests that subzero temperatures may have penetrated to a depth of over 285 m.     

Neotectonic evolution of the northern Laborec drainage basin (northeastern part of Slovakia)

This study investigates the influence of neotectonic activity on river and basin patterns in a mountainous area located in the northeastern part of the Carpathian Belt (the Laborecká vrchovina and Bukovské vrchy Mts. in eastern Slovakia). This area evolved within the accretionary wedge of the Carpathians during the Neogene, and it was alsowas affected by Middle to Late Miocene thrusting of the External Carpathians. Morphometric analysis, longitudinal and transverse river valley profiles, analysis of basin and valley symmetries, and investigation of alluvial terraces were carried out on the northern Laborec River and its tributaries. This was done to detect a possible relationship between their river courses and any ongoing neotectonic activity, which is otherwise difficult to detect by methods of structural geology because of the poorly exposed area.The general topography of the basin is characterized by a stepwise inclination to the SW as a result of differential uplift and subsidence. The reorganization of the river network in the Laborec drainage basin was influenced by tectonic activity along the NE-SW up to N-S fault structures during the neotectonic phase (Pliocene-Quaternary). The movement along these fault structures is predominantly normal to transtensive. The obtained data assumes that the region is under approximately NE-SW oriented S_H compression and NW-SE trending S_h tension. The Laborec drainage basin is characterized by a very high degree of asymmetry that sharply increases from the upper to the lower courses of the river. The right-bank tributaries of the Laborec River are < 12 km in length; however, the left-bank tributaries such as Vydraňka, Ol'šava, Výrava, Udava, and Cirocha Streams are up to 50 km long with a high potential of headward erosion and capturing. The valley asymmetry is also very variable in the upper and lower portions of the basin. Based on these presented results, the ancient river thalweg was located along the axis of the Hostovice-Habura depression, and it was captured by the Ol'šava, Výrava, and Udava Streams. The asymmetric pattern of the drainage basin is the result of active tectonics, the continual subsidence of the Transcarpathian Basin, and by the uplift of the Laborecká vrchovina and Bukovské vrchy Mts. These events caused rejuvenation of the headward erosion of streams in the southern part. Favorable lithology was also essential in the process of river capture.     

Multi-Wavelength Analysis of the 29 September 2002 M2.6/2N Flare

Using TRACE EUV 171 Å line, Hα line, Zürich radio, RHESSI, and HXRS observations the 29 September 2002 flare (M2.6), which occurred in AR NOAA 0134, was analyzed. Flaring structures were compared with a potential magnetic field model (field lines and quasi-separatrix layers) made from SOHO/MDI full-disk magnetogram. Series of high-resolution SOHO/MDI magnetograms and TRACE white-light images were used to find changes in the active region at the photosphere during the flare. The flare began with a rising of a small dark loop followed by the flare brightening observed in 171 Å with TRACE and Hα lines. In radio wavelengths, first type III bursts were observed 5 min prior to the start of hard X-ray emission, indicating a pre-flare coronal activity. The main hard X-ray emission peak (at 06:36 UT) was associated with the second type III burst activity and several slowly negatively drifting features, all starting from one point on the radio spectrum (probably a shock propagating through structures with different plasma parameters). After this time a huge loop formed and three minutes later it became visible in absorption both in Hα and 171 Å EUV lines. The phase of huge dark loop formation was characterized by long-lasting, slowly negatively drifting pulsations and drifting continuum. Finally, considering this huge loop as a surge an evolution of the event under study is discussed.     

Pre-processing of a sample of multi-scene and multi-date Landsat imagery used to monitor forest cover changes over the tropics

In support to the Remote Sensing Survey of the global Forest Resource Assessment 2010, the TREES-3 project has processed more than 12,000 Landsat TM and ETM+ data subsets systematically distributed over the tropics. The project aims at deriving area estimates of tropical forest cover change for the periods 1990-2000-2005. The paper presents the pre-processing steps applied in an operational and robust manner to this large amount of multi-date and multi-scene imagery: conversion to top-of-atmosphere reflectance, cloud and cloud shadow detection, haze correction and image radiometric normalization. The results show that the haze correction algorithm has improved the visual appearance of the image and significantly corrected the digital numbers for Landsat visible bands, especially the red band. The impact of the normalization procedures (forest normalization and relative normalization) was assessed on 210 image pairs: in all cases the correlation between the spectral values of the same land cover in both images was improved. The developed automatic pre-processing chain provided a consistent multi-temporal data set across the tropics that will constitute the basis for an automatic object-based supervised classification.     

Cathodoluminescence,fluid inclusion and stable C–O isotope study of tectonic breccias from thrusting plane of a thin-skinned calcareous nappe

Basal hydraulic breccias of alpine thin-skinned Muráň nappe were investigated by means of cathodoluminescence petrography, stable isotope geochemistry and fluid inclusions analysis. Our study reveals an unusual dynamic fluid regime along basal thrust plane during final episode of the nappe emplacement over its metamorphic substratum. Basal thrusting fluids enriched in ¹⁸O, silica, alumina, alkalies and phosphates were generated in the underlying metamorphosed basement at epizonal conditions corresponding to the temperatures of 400–450°C. The fluids fluxed the tectonized nappe base, leached evaporite-bearing formations in hangingwall, whereby becoming oversaturated with sulphates and chlorides. The fluids further modified their composition by dedolomitization and isotopic exchange with the host carbonatic cataclasites. Newly formed mineral assemblage of quartz, phlogopite, albite, potassium feldspar, apatite, dravite tourmaline and anhydrite precipitated from these fluids on cooling down to 180–200°C. Finally, the cataclastic mush was cemented by calcite at ambient anchizonal conditions. Recurrent fluid injections as described above probably enhanced the final motion of the Muráň nappe.     

Heavy metal distribution in karst soils from Croatia and Slovakia

With the use of the optimised three-step BCR sequential-extraction procedure it was possible to assess the mobility of selected elements in soil profiles from Croatian and Slovakian karst terrains. The soils in the Croatian karst were enriched in Cr, Ni, V, Mn, Cu, Cd and Mo, while soils from the Slovak Karst had high Pb and Zn concentrations. It was determined that the elements were most readily mobilised from the topsoil and the degree of mobility decreased with depth. Cr and Ni were mainly bound to the residual fraction, and Pb in the oxidisable fraction. Cu mobility was high in samples treated with agrochemicals throughout the soil profile.