In this study, we characterized glacial meltwater flow through a proglacial area with a focus on proglacial lakes and their hydrological regime and connection to a stream. The studied lakes showed a distinct development throughout an ablation season. For example at Lake 2, the mean daily water-level fluctuation amplitude increased from 0.07 (June) to 0.18 m (August), then dropped to 0.07 m (September). Glacial meltwater flows through the lakes and further downstream through a rock glacier rather fast (0.085 m/s), however only a small portion of water (< 1%) is routed efficiently. The complexity of the site‘s drainage system is supported by varying isotopic composition of water in the tarns situated on the rock glacier, with Tarn a) being the most enriched and Tarn c) the most depleted in heavy isotopes. The results from this study site provide new insights into the complexity of a drainage system connecting a glacier and a stream. Further research of the tarns and subsurface water routing could bring new knowledge about the temperature-related degradation and internal changes of the rock glacier. Considered significant global water storage and influencing hydrological conditions of watersheds, these landforms will certainly draw more attention in near future.

Falátková K., Šobr M., Slavík M., Bruthans J., Janský B. (2020): Hydrological characterization and connectivity of proglacial lakes to a stream, Adygine ice-debris complex, northern Tien Shan. Hydrological Sciences Journal 65, 610-623. (DOI)

Mercury distribution in topsoils and vegetation samples and temperature-dependent Hg mobilization simulating wildfires have been investigated near a Cu smelter in semi-arid Namibia. The thermo-desorption experiments performed on the representative Hg-rich topsoils indicated that >91% of the Hg was released at ~340°C, which corresponds to the predominant grassland-fire conditions. Despite the installation of a sulfuric acid plant in the smelter in 2015 and a calculated drop in the estimated Hg emissions (from 1301 ± 457 kg/y for the period 2004-2015 to 67 ± 5 kg/y after 2015), the Hg legacy pool in the smelter surroundings will contribute to wildfire-driven Hg emissions until its complete burn-out. Using the Hg spatial distribution data in the area (184 km²), the estimates indicate that up to 303 kg and 1.3 kg can be remobilized from the topsoils and vegetation, respectively.

Tuhý M., Rohovec J., Matoušková Š., Mihaljevič M., Kříbek B., Vaněk A., Mapani B., Göttlicher J., Steininger R., Majzan J., Ettler V. (2020): The potential wildfire effects on mercury remobilization from topsoils and biomass in a smelter-polluted semi-arid area. Chemosphere 247, 125972. (DOI)

Volcanic calderas are hazardous phenomena associated with cataclysmic eruptions that threaten surrounding nature, human society, and may also affect climate on a global scale. Active calderas are thus carefully monitored, however the underlying magma plumbing systems that store eruptible melt and feed ignimbrite eruptions are still poorly understood. In this paper, we have focused on the extinct Platoro caldera complex that erupted six large ignimbrite sheets between 30.2 Ma and 28.8 Ma in the Rocky Mountains (Colorado), and is associated with voluminous postcaldera intrusions. Using a multiparametric study (field mapping, petrography, radiometric dating, rock magnetism and anisotropy of magnetic susceptibility) of the Alamosa River pluton (29.0–27.3 Ma), we discovered an interesting behavior of magmatic activity that occurred after the main collapse episode. It has been documented that shallow-level magmatic systems of collapsed calderas remain active for another few millions of year, and produce multipulsed intrusions and complex dike swarms. Moreover, such intrusion are further distinguished as resurgent and postresurgent. The former induces ground deformation in form of uplifted domes, whereas the latter has no effect at the Earth´s surface.

Tomek F., Gilmer A.K., Petronis M.S., Lipman P.W., Foucher M.S. (2019): Protracted multipulse emplacement of a post‐resurgent pluton: the case of Platoro caldera complex (Southern Rocky Mountain volcanic field, Colorado). Geochemistry, Geophysics, Geosystems 20, 5225-5250. (DOI)

This paper presented a new field method for measuring the depth of the vaporization plane below surface of porous materials. The measuring device consisting of a rod, adhesive, and a water-soluble dye is placed into a porous material. As the pore water dissolves the dye, thus changing the device’s appearance, the dry and wet zones inside of the material can be visually distinguished. The suggested method is minimally destructive as it can be used in holes as small as 2 mm in diameter, relatively fast (typical measurement takes 10 min), and cost-effective compared to other available methods. We have conducted >500 measurements on a range of compact materials (sandstone, arkose, tuff, rhyolite), mostly on natural outcrops in humid continental, warm and cold semi-arid, and desert climates. It has been also shown that the method can find use in studying water presence in building materials or soil. We believe the method will give the scientific community a whole new perspective of water distribution especially in the near sub-surface of porous rocks for studying salt and cavernous weathering, lithophilic organisms, or water dynamics in both natural and artificial porous materials.

Weiss T., Mareš J., Slavík M., Bruthans J. (2020): A microdestructive method using dye-coated-probe to visualize capillary, diffusion and evaporation zones in porous materials. Science of The Total Environment 704, 135339 (DOI)

Our investigation was situated in the natural geochemical arsenic anomaly at Smolotely-Líšnice Au district (Central Bohemia). Using the combination of geochemical (bulk soil and pore water analyses, selective chemical extractions, S isotopes), mineralogical (XRD, TEM, SEM/EDS) and biological (DNA extraction) methods we characterized massive accumulations of authigenic arsenic and iron sulfides (realgar, bonazziite, pyrite and greigite) on the fragments of organic matter that were buried in the shallow wetland soil. We have shown that by the development of suitable conditions of sulfidogenesis (very fast microbial sulfate reduction vs. slow transfer of solutes), fragments of organic matter may play an active role in arsenic immobilization in wetland systems.

Knappová M., Drahota P., Falteisek L., Culka A., Penížek V., Trubač J., Mihaljevič M., Matoušek T. (2019): Microbial sulfidogenesis of arsenic in naturally contaminated wetland soil. Geochimica et Cosmochimica Acta 267, 33-50. (DOI)