Origin of the Coloured Karst Fills in the Neogene Extensional System of NE Iberia (Spain)

Karst fills from the onshore Penedès Basin and offshore València Trough display red, pink, orange and ochre colours. Their Mössbauer spectra indicate that Fe3+ contained in goethite is the dominant species in reddish-pink fills, whereas Fe2+ contained in dolomite and clays is more dominant in the orange and ochre ones. The lower δ13C values and higher 87Sr/86Sr ratios of the karst fills with respect to their host carbonates can reflect the input of soil-derived CO2 and an external radiogenic source into the karst system. This geochemical composition, together with the non-carbonate fraction of the fills, consists of authigenic and transported illite, illite-smectite interlayers, as well as kaolinite, chlorite, pyrite, quartz, ilmenite, magnetite, apatite and feldspar, account for a mixed residual-detrital origin of fills. This polygenic origin agrees with that of the terra rossa sediments described worldwide. The different colours of karst fills are attributed to fluctuations in the water table, which control the Eh/pH conditions in the karst system. Thus, reddish colours reflect low water table levels and oxidising episodes, and orange and ochre ones reflect high water table levels and more reducing episodes. The greenish colours of fills could be related to fluctuations in the Fe3+/Fe2+ ratio.

Radioactive Thoron 220Rn Exhalation From Unfired Mud Building Material Into Room Air of Earthen Dwellings

Thoron (220Rn), an isotope of radon with a strong α-decay energy, and its short-lived metallic progeny can pose an elevated lung cancer hazard in room air when unfired-soil derived building materials are used in earthen dwellings. Changes in moisture content and density influencing the thoron exhalation rate from earthen materials into room air were studied in the laboratory with terra rossa from a village on the Ðồng Văn Karst Plateau Geopark, Việt Nam, where ethnic minorities construct traditional dwellings with unfired terra rossa walls and floors. Our results show that the thoron exhalation rate from mud surfaces depends on (i) the content of radioactive parental nuclides in mineral components; (ii) the moisture content of mud where ∼5–10 weight % water maximizes the 220Rn exhalation rate; and (iii) the density of dry mud as primarily controlled by internal macroscopic voids, fractures, and porosity. Additional time-series of 220Rn exhalation data from an interior mud wall of a terra rossa-built house under different seasonal and weather conditions show that the temperature is influencing thoron exhalation via the water vapor pressure deficit (VPD) in air and the associated amount of atmospheric moisture adsorbed onto indoor mud surfaces. Our data suggest that occupants of “mud house” earthen dwellings in northern Việt Nam are exposed to an increased thoron geohazard during cooler weather, low VPD, and high relative humidity in air. Detailed studies are needed to evaluate the thoron geohazard for inhabitants of mud-built dwellings in other climates and geological terrains.

New data on geology of the Rybalsky Quarry, unique object of geological heritage of Global Significance

Among the great variety of geological relics of Ukraine, one of the most attractive is the Rybalsky Quarry, located in the city of Dnipro, and well known outside Ukraine. First of all, it is famous for the Mandrykivski Layers exposed in one of the ridges of the Quarry back in the 1970s, although there are many other important peculiarities of the geological structure of the Quarry which attract scientists from Ukraine, Germany, France, Netherlands, Russia and other countries. There are full data on the history of discovery and survey of the Mandrykivski Layers from their discovery by Valerian Domger in 1882 to current studies that reveal various aspects of geological structure of the Quarry, the results of study of different groups of fossil fauna, compare them with the fauna of the Paris Upper Eocene basin and other well- known locations. Particularly in the Rybalsky Quarry, thanks to the author`s efforts, the Layers received the status of “layers with geographic name”, as confirmed by the decision of Cenozoic Commission of the National Stratigraphic Committee of Ukraine in 2001. New fragments of the section of subaerial and subaqueous deposits of the Quaternary deposits were found and their composition, structure and complete stratigraphic content were studied. The research allows us to consider it typical for the Middle Prydniprovia. Fluvioglacial and lake-glacial deposits of the Dnipro glaciations in the Quarry exposed for the second time in 25 years, but this is the first time when their genetic origin, position in the section and lithological-facies peculiarities were determined. Thick layer of sands embedded on the roof of the Mandrykivski Layers were identified to the fifth or Hadzhybeiska terrace of the Dnipro, in the upper part of which there were notable siliceous-clayey-ferruginous formations or lateral crust (ferruginous crusts). The studies of the layer of brown-green and red-brown clays in the roof of the Mandrykivski layers allows us to presume their marine origin. In this case, they are underwater weathering crust (terra rossa) developed in the process of halmyrolysis or are the product of dissolution of carbonate silt enriched with detritus of mollusks, corals and other inhabitants of the warm Mandrykivske Sea.

Soil properties of agricultural area in karst terrain of Parakan, Pangandaran, West Java, Indonesia

a clayed soil characterized by reddish in colour, thick solum and neutral acidity. Farmers in Parakan area, Parigi District of Pangandaran, usually cultivate cash crops in terra rossa. Nowadays, farmers have no information about the properties of the soil, which is an important factor to maintain and increase plant productivity. The objective of this descriptive quantitative study was to verify the soil characteristic included physicochemical and microbiological properties in a selected agricultural field of Parakan. The soil samples were taken from three different areas covered with different vegetation. The study showed that terra rossa in the karst area is a non-saline soil with neutral acidity and low electrical conductivity. The texture of all soils were clay contained >50% clay particle. The soils were low in organic carbon, total nitrogen and available phosphor; but high in total phosphor and potassium, as well as cation exchange capacity. The population of soil microbes include total and fungal bacteria, as well as nitrogen-fixing Azotobacter and phosphate solubilizing bacteria, were average. In order to increase the organic carbon level; and the availability of phosphor and nitrogen, organic matter amendment is needed.

Metal-loaded zeolite remediation of soils contaminated with pandrug-resistant Acinetobacter baumannii

Due to the development of resistance to antimicrobial agents, bacterium Acinetobacter baumannii is nowadays a leading cause of nosocomial outbreaks. Clinically relevant A. baumannii outside hospital settings including natural soils affected by human waste represents a public-health risk for humans and animals. The aim of this study was to investigate the potential of metal-loaded zeolites to eliminate viable A. baumannii from artificially contaminated natural soils. A. baumannii isolate was subjected to the activity of natural zeolitised tuff (NZ) and Cu-modified (CuNZ) or Ag-modified zeolite (AgNZ) in wet, slightly acidic terra rossa and slightly alkaline red palaeosol. A. baumannii survived in terra rossa and red palaeosol supplemented with 1 wt% of NZ for seven days and four months, respectively. The addition of 1 wt% of CuNZ to terra rossa and red palaeosol shortened the survival of A. baumannii to three and 14 days, respectively. The addition of 0.1 wt% of AgNZ to both soils resulted in complete removal of viable A. baumannii within 1 h of contact, while the total native heterotrophic bacterial counts remained high. Since AgNZ is prepared with a simple modification of cost-effective and environmentally friendly natural zeolite, it is a promising material for the remediation of soils contaminated with pandrug-resistant A. baumannii.

Aeolian inputs as parent materials for Podzols and terra-rossa soils in a dolomitic landscape in the Italian Alps (Salmezza, BG, Italy)

<p>On an unglaciated karst landscape in the Lombard Pre-Alps (Salmezza, Bergamo, Italy), an extremely high pedodiversity occurs across a few hectares on Norian dolostone. The rock is locally enriched in well crystallized sand-grained quartz. The climate of the area is suboceanic, with >1500 mm of annual rainfall, and an average temperature around 6-8°C. Rendzic Leptosols and Phaeozems are developed on the steepest slopes, Podzols, Cambisols and Luvisols on flatter areas, while Rhodic Luvisols/Alisols (Terra-Rossa soils) are found in doline cracks and crevices. The sand-grained quartz content of the parent rock seems to be the main soil differentiating factor: where it is abundant (ca. 10-20% in volume), it is responsible for the genesis of Podzols.</p><p>We sampled and analyzed 9 soil profiles from the Salmezza area, thus characterizing all pedogenic processes active in the area. In particular, we analyzed standard soil chemical properties (pH, organic carbon, base status and Cation Exchange Capacity, dithionite and oxalate-extractable Fe and Al); we performed a total elemental analysis on most samples and on substrate samples, in order to calculate mass balance and element loss and enrichment; we observed thin sections and performed XRD analysis in powder samples and on the clay fraction of most pedogenic horizons as well.</p><p>The parent material is a rather pure dolostone, composed of dolomite, locally enriched in quartz. No other minerals have been observed. Very little amounts of Fe, Al and other elements are thus included in the parent rock (almost completely composed of Ca, Mg and Si), often very close to the analytical detection limit. Ca and Mg were almost completely lost during most soil forming processes in this temperate humid climate, while the enrichment in Si, Fe, Al varies broadly amidst the different soils, thanks to different pedogenic processes. Fe and Al, in particular, were up to 120 times more concentrated in Bt and Bhs horizons than in the parent rock. The ratios between stable elements in rocks and soils verifies important inputs of aeolian materials. The values are, however, different also amidst different soils, so an univocal origin of aeolian materials cannot be hypothesized. The mineralogy of the clay fraction is also strongly modified by pedogenesis, so that each soil type is characterized by a different mineralogical assemblage, making it difficult to detect signatures of specific aeolian origins as well.</p>