Various Approaches to Forward and Inverse Wide-Angle Seismic Modelling Tested on Data from DOBRE-4 Experiment

The interpretation of seismic refraction and wide angle reflection data usually involves the creation of a velocity model based on an inverse or forward modelling of the travel times of crustal and mantle phases using the ray theory approach. The modelling codes differ in terms of model parameterization, data used for modelling, regularization of the result, etc. It is helpful to know the capabilities, advantages and limitations of the code used compared to others.This work compares some popular 2D seismic modelling codes using the dataset collected along the seismic wide-angle profile DOBRE-4, where quite peculiar/uncommon reflected phases were observed in the wavefield.The ~505 km long profile was realized in southern Ukraine in 2009, using 13 shot points and 230 recording stations. Double P_MP phases with a different reduced time (7.5–11 s) and a different apparent velocity, intersecting each other, are observed in the seismic wavefield. This is the most striking feature of the data. They are interpreted as reflections from strongly dipping Moho segments with an opposite dip. Two steps were used for the modelling. In the previous work by Starostenko et al. (2013), the trial-and-error forward model based on refracted and reflected phases (SEIS83 code) was published. The interesting feature is the high-amplitude (8–17 km) variability of the Moho depth in the form of downward and upward bends. This model is compared with results from other seismic inversion methods: the first arrivals tomography package FAST based on first arrivals; the JIVE3D code, which can also use later refracted arrivals and reflections; and the forward and inversion code RAYINVR using both refracted and reflected phases. Modelling with all the codes tested showed substantial variability of the Moho depth along the DOBRE-4 profile. However, SEIS83 and RAYINVR packages seem to give the most coincident results.     

Sediment lithology and stable isotope composition of organic matter in a core from a cirque in the Krkonoše Mountains,Czech Republic

This study presents detailed lithostratigraphy and stable carbon and nitrogen isotopic variations in a 520-cm-long sediment core from a cirque basin in the Labsky důl Valley, Krkonoše Mountains, Czech Republic. Detailed study of the core reveals five major periods of sedimentation during the last 7600 years: silt and sand deposition during ~7.6–5.1 ka cal BP, Sphagnum peat accumulation during ~5.1–4.0 ka cal BP, sandy silt and sand during ~4.0–2.8 ka cal BP, raised peat bog during ~2.8–2.0 ka cal BP (Sphagnum peat), and sedimentation of sandy silt since ~2.0 ka cal BP. The δ¹³C values of the organic matter in the core vary in the range typical for C3 plants, from −24.35 to −27.68‰, whereas the δ¹⁵N values vary from −2.65 to +4.35‰. Core sections having ash contents ≥70% have δ¹⁵N > 1‰ and δ¹³C < −26‰, whereas those having ≤70% ash content have δ¹⁵N < 1‰ and δ¹³C > −26‰. Strong linear correlations are observed between δ¹³C and δ¹⁵N values as well as between C:N ratios and δ¹⁵N values in the horizons with ash content >10%, primarily for sand and silt horizons. On the other hand, poor correlations between δ¹³C and C:N ratio, as well as δ¹⁵N and C:N ratio, were observed in Sphagnum peat layers (45–125 and 185–265 cm). We conclude that the primary stable isotope variations are not preserved in the layers where significant correlation between δ¹⁵N and C:N ratio is observed. The relatively small δ¹³C variation in the uppermost Sphagnum peat layer suggests stable temperature during ~2.8–2.0 ka cal BP.     

Timing of glacier advances and climate in the High Tatra Mountains (Western Carpathians) during the Last Glacial Maximum

During the Last Glacial Maximum (LGM), long valley glaciers developed on the northern and southern sides of the High Tatra Mountains, Poland and Slovakia. Chlorine-36 exposure dating of moraine boulders suggests two major phases of moraine stabilization, at 26–21 ka (LGM I — maximum) and at 18 ka (LGM II). The dates suggest a significantly earlier maximum advance on the southern side of the range. Reconstructing the geometry of four glaciers in the Sucha Woda, Pańszczyca, Mlynicka and Velicka valleys allowed determining their equilibrium-line altitudes (ELAs) at 1460, 1460, 1650 and 1700 m asl, respectively. Based on a positive degree-day model, the mass balance and climatic parameter anomaly (temperature and precipitation) has been constrained for LGM I advance. Modeling results indicate slightly different conditions between northern and southern slopes. The N–S ELA gradient finds confirmation in slightly higher temperature (at least 1 °C) or lower precipitation (15%) on the south-facing glaciers during LGM I. The precipitation distribution over the High Tatra Mountains indicates potentially different LGM atmospheric circulation than at the present day, with reduced northwesterly inflow and increased southerly and westerly inflows of moist air masses.     

Mycobiota of the disused ore mine of Marcinków in?nie?nik Masiff(western Poland)

Marcinków(Lower Silesia, ?nie?nik Masiff,south-western Poland) has been a well-known mining centre since the mid-15 th century. Mineral extraction ended in 1949 with the ores of Pb, Ag, Cu and occasionally Au, U or graphite mined there. The mine is surrounded by metamorphic graphite and mica schist. It is not open to the public and no bats have been recorded living in. The aim of this study was the mycological analysis of the air, the rock surface and the water of the disused ore mine of Marcinków.Additionally, the chemical composition of rocks and water, and microclimate conditions of the adit were determined. Fungi were identified using a combination of phenotypic and molecular methods.Six taxa of fungi were cultured from the indoor air samples of the adit, whereas the outdoor air samples contained only five taxa. On the other hand, nine taxa were isolated from both the rocky walls and the water.The Aspergillus group was present only on the rocks and in the water, whereas Cladosporium herbarum,Dumontinia tuberosa, Epicoccum nigrum, Hirsutella sp., were found exclusively in the air. The mycobiota found in the ore mine were mostly similar to those recorded in other mines and natural caves. However,it should be noted that the internal microclimate and chemical compounds of the rocks.