Stages of development in the Polish Carpathian Foredeep basin

In southern Poland, Miocene deposits have been recognised both in the Outer Carpathians and the Carpathian Foredeep (PCF). In the Outer Carpathians, the Early Miocene deposits represent the youngest part of the flysch sequence, while in the Polish Carpathian Foredeep they are developed on the basement platform. The inner foredeep (beneath the Carpathians) is composed of Early to Middle Miocene deposits, while the outer foredeep is filled up with the Middle Miocene (Badenian and Sarmatian) strata, up to 3,000mthick. The Early Miocene strata are mainly terrestrial in origin, whereas the Badenian and Sarmatian strata are marine. The Carpathian Foredeep developed as a peripheral foreland basin related to the moving Carpathian front. The main episodes of intensive subsidence in the PCF correspond to the period of progressive emplacement of the Western Carpathians onto the foreland plate. The important driving force of tectonic subsidence was the emplacement of the nappe load related to subduction roll-back. During that time the loading effect of the thickening of the Carpathian accretionary wedge on the foreland plate increased and was followed by progressive acceleration of total subsidence. The mean rate of the Carpathian overthrusting, and north to north-east migration of the axes of depocentres reached 12 mm/yr at that time. During the Late Badenian-Sarmatian, the rate of advance of the Carpathian accretionary wedge was lower than that of pinch-out migration and, as a result, the basin widened. The Miocene convergence of the Carpathian wedge resulted in the migration of depocentres and onlap of successively younger deposits onto the foreland plate.     

Determination of the apparent copper complexing capacity of seawater by anodic stripping voltammetry

A new experimental technique using differential pulse anodic stripping voltammetry with a thin-film mercury electrode and efficient mixing of the electrolyte for the apparent copper complexing capacity of seawater is proposed. The effects of some factors such as type of electrode and cell, pH of the solution, potential of deposition, time of equilibration, and influence of a non-ionic surface active agent on the measurements are examined. Experimental results for the apparent copper complexing capacity of seawater are calculated presuming 1:1 inert complex formation. By using EDTA as a model ligand, it is shown that the proposed procedure with efficient mixing of the solution excludes any appreciable kinetic influence upon the electroanalytical results.     

Combined statistical and petrological analysis of provenance and diagenetic history of mudrocks: Application to Alpine Tethydes shales (Sicily,Italy)

Mineralogical (X-ray diffraction) and geochemical (X-ray fluorescence) compositional data of Alpine Tethyde mudrocks from Sicily were used to unravel the interplay of provenance and diagenesis by means of multivariate statistical methods (PCA, discriminant function analysis) designed for non-negative constant-sum data. The Sicilian Alpine Tethydes comprise Cretaceous–Eocene scaly shales (Mt. Soro and Upper Scagliose Shales Units), Eocene–Oligocene variegated shales (Troina and Nicosia Units), and Miocene Numidian shales (Nicosia Unit). The use of biplots of clr-transformed variables allows discrimination of two different groups of shales. High CIA values reveal a strongly weathered source area especially for the Numidian shales. The analyses of mixed-layered clay minerals indicate that the behaviour of K2O and geochemical affine elements is controlled by the diagenetic grade, which increases from south-west to north-east in response to tectonic loading. Ratios of selected elements (Zr, Y, La, Nb, Ti, Co, Cr, Ni), considered essentially unchanged with respect to the source rocks, are similar in the scaly and variegated shales, and resemble the Variscan Peloritani metamorphic basement. In contrast, the distinct geochemical signature of the Numidian shales reveals a source similar to the average cratonic sandstone, suggesting derivation from external sources located in the foreland. Multivariate discriminant analysis performed on selected trace elements confirms the previous suggestions.     

Field-scale Variations in Plant and Grasshopper Communities: A GIS-based Assessment

GIS technology allowed us to examine species-specific occurrence and abundance patterns of important grassland herbivore species through the use of appropriate statistical methods and the superior spatial representation commonly available in existing GIS packages. The study was conducted on a 254 ha grassland area located 10 km south of Three Forks, Gallatin County, Montana, in the Agropyron spicatum province of the western steppe region of the U.S.A. From an ecological perspective, grasshopper species distribution and abundance patterns observed on a local, non-uniform landscape (2.6 km 2) were consistent with results found in other studies at the valley (≈1,400 km 2) and state-level (≈237,000 km 2) scales. Our observations at the local scale further demonstrate the importance of vegetation type and specific local stand physiognomies in structuring grasshopper populations. The application of results from studies conducted at various scales to the development of decision support tools for resource managers is also discussed.     

The use of the slope–area function to analyse process domains in complex badland landscapes

This paper explores the effectiveness of the widely-used functional relationship between drainage area (A in m²) and slope (S in m/m) to identify local process domains and aid interpretation of process interactions in a complex badland landscape. In order to perform this investigation, a series of sub-basins tributary to the Formone River in the Orcia catchment (central Italy) were selected as a suitable study area within which to explore our questions, given these basins' general representativeness of local terrain, the availability of a high resolution digital terrain model and previous extensive geomorphological research. Eroding basins containing both calanchi and landslides are common in the sub-humid badland landscape of central Italy, where field observation identifies a complex pattern of erosive processes associated with a history of uplift, despite which parts of the local landscape appear disconnected. Results reveal that the shape of all S–A curves (plotted using S data binned on log A) is comparable with that described in the literature, although sub-basins containing calanchi generally plot with higher S values than non-calanchi ones, except in the ‘fluvial’ section of the plots. Second, when viewed on total data (non-binned) S–A plots, landslide source area domains and calanchi domains are entirely coincident in all basins, supporting a cause–effect relationship. Additional plotting of the frequency characteristics of the raw data in a new way supports the interpretation that calanchi frequently initiate in landslide scars. In general though, although the S–A plots can contribute to the disentanglement of geomorphological behaviour in some complex erosional landscapes, it became apparent that in this landscape, process domains do not separate out with clarity along the A axis as suggested by theory. Despite this, an alternative, broader-scale morphoevolutive model can be proposed for the development of within-landslide calanchi, driven by changes to basin connectivity to the base channel. © 2018 John Wiley & Sons, Ltd.     

The usefulness of UV–visible and fluorescence spectroscopies to study the chemical nature of humic substances from soils and composts

The aim of this work is to study the suitability of the use of fluorescence and UV–visible spectroscopies to evaluate the humification degree of different organic alkaline extracts obtained from diverse materials (humic substances, composted and non-composted materials). Our results indicate that the complementary utilization of the fluorescence index proposed by Milori et al. [Milori, D., Martin-Neto, L., Bayer, C., Mielniczuk, J., Vagnato, V., 2002. Humification degree of soil humic acids determined by fluorescence spectroscopy. Soil Science, 167, 739–749] (the total area of the emission spectra collected over a range of 460–650 nm using an excitation wavelength of 465 nm), the ratio between the electron-transfer band and benzenoid band of benzene UV light absorption, and the molar absorption coefficients at 600 nm and 280 nm proved capable of discriminating between extracts obtained from non-humified, partially humified and very humified materials.Likewise, our results suggest that humification is related to increments in the aromatic character of the molecules, which may be reflected in the presence of more aromatic rings and/or more condensed polyaromatic structures, and the degree of substitution in aromatic rings with polar functional groups, as well as to the possible increase in the conjugation degree in unsaturated aliphatic chains.     

Growth Dynamics, Production, and Nutrient Status of the Seagrass Cymodocea nodosa in a Mediterranean Semi-Estuarine Environment

Abstract. Cymodocea nodosa is a relatively small seagrass species which is common in the Mediterranean. An intensive survey on its growth and production was carried out in a dense, monospecific stand located in a semi-estuarine embayment. Data on leaf appearance and growth, shoot recruitment and death, rhizome growth, above- and belowground biomass, and nutrient content in the different parts of the plant were obtained over 2 years. All these variables showed a clear seasonality. In general, maximum growth and production occurred in early summer (July), and maximum biomass was reached between July and September. Biomass, shoot density, growth and production showed clear minima in winter.     

Pyroclastic deposits of the November 13, 1985 eruption of Nevado del Ruiz volcano, Colombia

The November 13, 1985 eruption of Nevado del Ruiz produced a series of pyroclastic flows and surges that eroded channels on the surface of the summit glacier and generated lahars which descended down most of the rivers that drain the volcano. The stratigraphy of the proximal pyroclastic deposits indicates that there were at least four episodes to the eruption. Episode I, deposited an unusual surge consisting of small pieces of ice mixed with ash and exhibiting planar stratification. Ballistically emplaced fragments are also intercalated with this unit. During Episode II, at least two pyroclastic flows were erupted. Their deposits contain the most evolved pumice of the entire eruption; SiO₂ content of matrix glass ranges between 74.5 and 74.9%. Episode III is marked by the emplacement of a welded tuff with an average SiO₂ content of about 66% in the matrix glass. The final Episode IV was characterized by the development of a high-altitude eruption column and the emplacement of several nonwelded pyroclastic flows. Banded pumice are common in the pyroclastic flow as well as in the pumice fall deposits. Co-existing dark and light pumice bands differ in SiO₂ content by 3.5% and in general are similar to the composition of the welded pumice from Episode III.The compositional zonation of the pyroclastic deposits from Episode I to IV suggests that a nearsurface compositionally-stratified portion of the magma body was tapped during Episode II. During Episodes III and IV the main body of magma was involved although the coexistence of the compositionally distinct pumice clasts at similar stratigraphic levels argues for mixing of magma from different levels in the chamber during the eruptive process.