Fore-Sudetic Monocline Research Articles

Modern Geochemical and Tectonic Exploration—The Key Factor in Discovering the Northern Copper Belt, Poland

The discovery of the Northern Copper Belt in SW Poland is a result of an extensive exploration project with a key role played by various science-related methods. The project relied on mapping the distribution of mineral zones in the entire Fore-Sudetic Monocline, a unit known for its occurrences of Cu-Ag orebodies. This approach involved the examination of historical drill cores from over 400 oil and gas holes in this area, with the collection of samples for laboratory analyses. A close relationship was confirmed between the distribution of orebodies and the transformation of organic matter. Rock-Eval pyrolysis was also performed on selected samples. The tests of rock specimens were accompanied by the reprocessing of historical gravimetric and seismic surveying results. Field magnetotelluric surveying was also performed in certain areas. This phase resulted in the identification of areas with a high probability of finding the best ore, allowing for the initiation of the drilling stage. So far, 37 exploratory boreholes have been drilled in those locations, nearly all of them with highly positive results. The Northern Copper Belt consists of three deposits, Nowa Sól, Mozów, and Sulmierzyce North, along with numerous prognostic areas distributed therebetween. The future production of copper, silver, and the accompanying valuable elements presents a chance to provide the whole of Europe with a new plentiful supply of those critical raw materials.

Hydrochemical background of 222Rn in surface waters of Lower Silesia (SW Poland)

The purpose of the conducted research was to create the first Polish database on 222Rn activity concentration in surface (river) waters in one of Poland’s 16 voivodeships (the highest-level administrative division unit in Poland), and thereby complement the worldwide database on 222Rn activity concentration in such waters. To this end, the research area was limited to Lower Silesian voivodeship (6.4% of the area of Poland; 7.8% of its population), which, in geological terms, can be divided into three parts differing in geological structure, characterised by a decreasing proportion of crystalline rocks on the surface. The ranges of 222Rn activity concentrations measured in these areas were: 0.21–24.44 Bq/dm3 for the Sudetes, 0.08–4.27 Bq/dm3 for the Fore-Sudetic Block, and 0.09–3.37 Bq/dm3 for the Fore-Sudetic Monocline. Based on the obtained 222Rn activity concentrations in river waters, the authors determined the hydrochemical background. It was: 0.26–1.33 Bq/dm3 for the Sudetes, 0.18–0.92 Bq/dm3 the Fore-Sudetic Block, and 0.12–0.48 Bq/dm3 for the Fore-Sudetic Monocline. The range of 222Rn activity concentrations measured in river waters in the whole Lower-Silesian voivodeship was 0.08–24.44 Bq/dm3. It means that river waters in this voivodeship satisfy the radiologic requirements for water intended for human consumption in terms of 222Rn activity concentration.

Assessment of the hydrocarbon potential of copper-bearing shale from southern part of the Fore-Sudetic Monocline

"Głównym celem pracy była próba określenia możliwości generacji węglowodorów z poziomu łupku miedzionośnego na podstawie wyników badań pirolitycznych. W celu oceny materii organicznej 13 próbek rdzeniowych pochodzących z rejonu złóż rud miedzi w południowej części monokliny przedsudeckiej poddano badaniom pirolitycznym Rock-Eval. Dodatkowo próbki skalne badano również przy użyciu pirolizy wysokotemperaturowej sprzężonej z kapilarną chromatografią gazową (Py-GC/FID) i studiowano pod kątem zmienności trzech grup węglowodorowych: lekkich – C1–C9, ciekłych – C10–C15 oraz ciężkich – powyżej C15+. W przypadku każdej próbki została zastosowana jednoetapowa piroliza, prowadzona w programowanej temperaturze 500°C przez 0,4 min. Uzyskane wyniki były interpretowane kompleksowo i pozwoliły na rozróżnienie charakteru generowanych produktów na podstawie dystrybucji węglowodorów otrzymanych w wyniku pirolizy substancji organicznej zawartej w skale. Do określenia potencjalnych możliwości generacyjnych badanych łupków miedzionośnych wykorzystano zarówno udział procentowy poszczególnych frakcji, jak też bezwymiarowy wskaźnik uzysku (liczony z analizy Py-GC/FID). Na podstawie wyników badań pirolitycznych Rock-Eval oraz zbieżnych z nimi wartości wskaźników uzysku Py-GC/FID stwierdzono doskonały potencjał węglowodorowy dla wybranych próbek pochodzących z poziomu łupku miedzionośnego. Stopień dojrzałości substancji organicznej wyrażony poprzez parametr Tmax w przypadku większości badanych próbek z poziomu łupku miedzionośnego mieści się w zakresie okna ropnego, co potwierdziły również badania Py-GC/FID. Dodatkowo o możliwości generacji węglowodorów świadczy fakt występowania wysokiej zawartości ekstrahowalnej substancji organicznej oraz bardzo wysoka wartość parametru S2 (nawet do 41,88 mg HC/g skały). Analiza wyników badań geochemicznych pod kątem oceny potencjału generacyjnego poziomu łupku miedzionośnego udowodniła, że poziom ten nie powinien być pomijany jako potencjalnie macierzysty przy rozpatrywaniu źródła napełniania pułapek węglowodorów w systemie naftowym Niżu Polskiego."

Influence of Rheological Parameters of the Fore-Sudetic Monocline Plastic Rocks on the Process of Drilling Boreholes

Influence of Rheological Parameters of the Fore-Sudetic Monocline Plastic Rocks on the Process of Drilling Boreholes

Comparison of main and accompanying metals distribution patterns in newly documented deposits of the Northern Copper Belt in Poland

Three new world-class sediment-hosted stratiform copper deposits have recently been documented in SW Poland, in the deep parts of the Fore-Sudetic Monocline: Nowa Sól, Sulmierzyce North and Mozów. Along with the adjacent prognostic areas, these deposits form an extensive west–east-trending belt, distant from the well-known deposits of the Sieroszowice–Lubin area and referred to as the Northern Copper Belt. This major discovery was a result of an exploration program performed by the Canadian Miedzi Copper Corporation, which involved studies of archival data and the company's own drilling program. Investigation of the core material included microscopic observations of thin sections and chemical analyses using inductively coupled plasma (ICP) mass spectrometry and/or ICP optical emission spectrometry. The aim of this study was to compare available geochemical data from the documented deposits and determine the distribution patterns of the main and accompanying metals. Particular attention was paid to Cu, Ag, Pb, Zn, Co, Ni, Mo, V and Au. Each of the studied deposits is characterized by a different position of the ore mineralization in the lithological profile. Average concentrations of the analysed elements and their distribution in the ore series, both vertically and laterally, indicate that distinct mineralizing systems were responsible for the formation of each orebody. Among the main factors influencing metal distribution in the analysed deposits are: the spatial range of the epigenetic, oxidized Rote Fäule facies; composition and thickness of the source rocks for the mineralizing brines; and tectonics.

Thermal properties of rocks from deep boreholes in Poland in terms of obtaining geothermal energy from enhanced geothermal systems

In the case of unconventional geothermal systems, the thermal conditions are decisive, i.e. heat flux and temperature at a certain depth, and the physical properties of rocks, their susceptibility to fracturing, etc., which should be determined on a local scale. The work carried out was aimed at determining the basic thermal parameters of rocks, i.e.: effusivity, thermal conductivity and diffusivity, basing on tests of samples taken from boreholes, representing selected geothermal structures in Poland. Both high-temperature structures (100-135 °C) recognized up to a depth of about 3,800 m within the Fore-Sudetic Monocline and up to about 3,000 m in the Szczecin Synclinorium and the Leba Elevation, as well as medium-temperature structures (60-90 °C), occurring at depth 2,000- 2,500 m (Warszawa Synclinorium, Lublin Synclinorium), were analyzed. Some samples representing low temperature structures (with temperatures below 60 °C), such as Lublin synclinorium and Podlasie-Lublin elevation from depths from about 1,000 to 1,500 m, were also analyzed. The tests of thermal parameters of rocks coupled with simulations showed, that the formations with the highest mean diffusivity and thermal conductivity values are characterized by the largest thermal penetration depth and smallest temperature drop. The research allowed to conclude that among the examined rocks, the Cambrian sandstones of the Leba Elevation and the Zechstein dolomites of the Fore-Sudetic monocline are characterized by the most appropriate parameters from the point of view of obtaining geothermal energy from the enhanced geothermal systems in Poland. Cited as: Labus, K., Labus, M., Leśniak, G. Thermal properties of rocks from deep boreholes in Poland in terms of obtaining geothermal energy from enhanced geothermal systems. Advances in Geo-Energy Research, 2023, 8(2): 76-88. https://doi.org/10.46690/ager.2023.05.02

Hydrogen sulphide (H2S) migration in groundwater of the Zechstein strata in the Legnica-Głogów Copper Basin and its vicinity, SW Poland

Hydrogen sulphide (H2S) occurs in groundwater in various lithostratigraphic units of the Zechstein Basin in the Legnica-Głogów Copper Basin (SW Poland). This region is located in the Fore-Sudetic Monocline within which, several tens of kilometres NE of the study area, at greater depths, natural gas fields with hydrogen sulphide (H2S) occur. The Main Dolomite (Ca2), in which H2S-containing natural gas has accumulated, is younger than the Zechstein Limestone (Ca1), which is actively mined. The Ca2 and Ca1 formations are separated by a thick anhydrite succession including a wedge-shaped salt body. Hydrochemical analyses of 18 groundwater samples taken from different horizons within the Zechstein strata showed spatial variability ofH2S and chloride concentrations. A conceptual model of groundwater flow with dissolved H2S in the Zechstein formations was developed. H2S migration is associated with groundwater flow between the Ca2 and Ca1 aquifers through fissures in the anhydrite strata that separate them. Hydraulic contact through fissures in the anhydrite layers is the result of long-term exploitation of the underground copper deposit. Groundwater flow between the layers is influenced by a large change in the piezometric pressure of the groundwater in the depression cone caused by mining drainage.

222Rn and 226Ra concentrations in selected shallow circulation groundwaters from the Fore-Sudetic Monocline area

Natural radioactive isotopes occur in various components of the natural environment, including groundwater. The general population, not always aware of possible threats, can use its resources. The activity concentration of some of the radioactive isotopes should be monitored, especially in those intakes from which it is possible to obtain water for human consumption, e.g. in domestic wells. The conducted research was innovative due to the fact that in many countries, including Poland, there are no regulations on waters exploited from home wells using as a drinking water source. As the groundwaters from this area have not been examined for radon (222Rn) and radium (226Ra) occurrence yet, the goal of this research was to perform screening tests in this part of the Fore-Sudetic Monocline. For this purpose, the authors have measured the concentration of 222Rn and 226Ra activity in groundwater collected from this geological unit located in south-western Poland. 222Rn and 226Ra occurrence was researched, and specific electrolytic conductivity, redox potential, pH and temperature were measured in 52 groundwater samples. 222Rn activity concentration ranged from 0.18 to 19.78 Bq/dm3. Only in three cases, 226Ra activity concentration reached a value above the lower detection limit of the applied method, i.e. 0.05 Bq/dm3 (max. 0.77 Bq/dm3). The authors present completely new data on the occurrence of these radioactive isotopes in the waters of the first aquifer in the Fore-Sudetic Monocline, which is not without significance for the health of consumers of these waters.

Potential for Underground Storage of Liquid Fuels in Bedded Rock Salt Formations in Poland

The paper aims to give a universal methodology for assessing the storage capacity of a bedded rock salt formation in terms of the operational and strategic storage facilities for liquid fuels. The method assumes the development of a geological model of the analyzed rock salt formation and the determination of the salt caverns’ size and spacing and the impact of convergence on their capacity during operation. Based on this method, the paper presents calculations of the storage capacity using the example of the bedded rock salt formations in Poland and their results in the form of storage capacity maps. The maps show that the analyzed rock salt deposits’ storage capacity in northern Poland amounts to 7.1 B m3 and in the Fore-Sudetic Monocline to 10.5 B m3, in the case of strategic storage facilities. The spatial analysis of the storage capacity rasters, including determining the raster volumes and their unique values, allowed us to quantify the variability of the storage capacity in the analyzed rock salt deposits.

Postdiagenetic Changes in Kerogen Properties and Type by Bacterial Oxidation and Dehydrogenation

A significant part of organic carbon found on the earth is deposited as fossil organic matter in the lithosphere. The most important reservoir of carbon is shale rocks enriched with organic matter in the form of kerogen created during diagenesis. The purpose of this study was to analyze whether the bacterial communities currently inhabiting the shale rocks have had any impact on the properties and type of kerogen. We used the shale rock located on the Fore-Sudetic Monocline, which is characterized by oil-prone kerogen type II. We were able to show that shale rock inhabited by bacterial communities are characterized by oxidized and dehydrated kerogen type III (gas-prone) and type IV (nonproductive, residual, and hydrogen-free). Bacterial communities inhabiting shale rock were dominated by heterotrophs of the Proteobacteria, Firmicutes, and Actinobacteria phyla. Additionally, we detected a number of protein sequences in the metaproteomes of bacterial communities matched with enzymes involved in the oxidative metabolism of aliphatic and aromatic hydrocarbons, which may potentially contribute to the postdiagenetic oxidation and dehydrogenation of kerogen. The kerogen transformation contributes to the mobilization of fossil carbon in the form of extractable bitumen dominated by oxidized organic compounds.

Comparison of 3D, 2D, and 1D Magnetotelluric Inversion Results on the Example of Data from Fore-Sudetic Monocline

This study’s main objective is to better define and understand results for the most commonly used inversion algorithms in magnetotelluric data interpretation as part of geological exploration of the region of the Dolsk fault and the Odra fault. The data obtained from the eastern part of Fore-Sudetic Monocline measurements were used to describe the boundaries of lithospheric blocks (terranes) and recognize their origin. The magnetotelluric (MT) soundings were carried out to achieve this goal. There were conducted 51 soundings on five quasiparallel profiles. That allows constructing a quasiregular mesh in the area of the Fore-Sudetic Monocline. This arrangement of the measuring grid allowed reducing the influence of the largest sources of disturbances on MT data. 1D and 2D models were created by using the inverse algorithms. The models were prepared for each profile separately. Further, parallel (ModEM) 3D inversion codes were applied. The area where the investigation was done involves the region of the Dolsk fault and the Odra fault. These zones are essential geologic borders of a regional nature, and they pull apart the crust blocks with different origins. It was vitally needed to correctly identify the crust and upper mantle structure around a part of the Fore-Sudetic Monocline. The paper shows how these key features of the geological structures are revealed using 1D, 2D, and 3D algorithms.

Postdiagenetic Bacterial Transformation of Nickel and Vanadyl Sedimentary Porphyrins of Organic-Rich Shale Rock (Fore-Sudetic Monocline, Poland).

Nickel and vanadyl porphyrins belong to the so-called fossil geo- or sedimentary porphyrins. They occur in different types of organic matter-rich sediments but mostly occur in crude oils and their source rocks, oil shales, coals, and oil sands. In this study, we aimed to understand the process of bacterial transformation of geoporphyrins occurring in the subsurface shale rock (Fore-Sudetic Monocline, SW Poland). We studied these transformations in rock samples directly obtained from the field; in rock samples treated with bacterial strain isolated from shale rock (strain LM27) in the laboratory; and using synthetic nickel and vanadyl porphyrins treated with LM27. Our results demonstrate the following: (i) cleavage and/or degradation of aliphatic and aromatic substituents of porphyrins; (ii) degradation of porphyrin (tetrapyrrole) ring; (iii) formation of organic compounds containing 1, 2, or 3 pyrrole rings; (iv) formation of nickel- or vanadium-containing organic compounds; and (v) mobilization of nickel and vanadium. Our results also showed that the described bacterial processes change the composition and content of geoporphyrins, composition of extractable organic matter, as well as nickel and vanadium content in shale rock.

Biosynthesis of Tetrapyrrole Cofactors by Bacterial Community Inhabiting Porphyrine-Containing Shale Rock (Fore-Sudetic Monocline).

This study describes for the first time the comprehensive characterization of tetrapyrrole cofactor biosynthetic pathways developed for bacterial community (BC) inhabiting shale rock. Based on the genomic and proteomic metadata, we have detailed the biosynthesis of siroheme, heme, cobalamin, and the major precursor uroporphyrinogen III by a deep BC living on a rock containing sedimentary tetrapyrrole compounds. The obtained results showed the presence of incomplete heme and cobalamin biosynthesis pathways in the studied BC. At the same time, the production of proteins containing these cofactors, such as cytochromes, catalases and sulfite reductase, was observed. The results obtained are crucial for understanding the ecology of bacteria inhabiting shale rock, as well as their metabolism and potential impact on the biogeochemistry of these rocks. Based on the findings, we hypothesize that the bacteria may use primary or modified sedimentary porphyrins and their degradation products as precursors for synthesizing tetrapyrrole cofactors. Experimental testing of this hypothesis is of course necessary, but its evidence would point to an important and unique phenomenon of the tetrapyrrole ring cycle on Earth involving bacteria.

Formation of Diagenetic Minerals in the Carboniferous Rock Complex from the Fore-Sudetic Monocline (SW Poland): Fluid Inclusion, Isotopic and Raman Constraints

The paper presents the latest state of knowledge on clastic sedimentary rocks from the Carboniferous complex in the SW part of the Polish Lowlands, studied to help determine their potential prospectivity for the occurrence of oil and/or gas deposits. Rocks were analyzed with respect to the petrographic-mineralogical characteristics of the Carboniferous deposits, their diagenesis, determinations of pressure-temperature conditions of mineral formation and the hydrocarbon occurrence. Analyses were carried out on samples from four selected boreholes in the Fore-Sudetic Monocline. After microscopic analysis of rocks and minerals in thin sections, the following techniques were used: luminescence analysis (UV, blue light), microthermometric analysis of fluid inclusions in double-sided polished wafers, cathodoluminescence analysis, electron scanning microscope studies, XRD analyses, stable isotopic analyses (carbon, oxygen) on calcite and dolomite-ankerite and Raman spectra of fluid inclusions. Orthochemical components, such as carbonates and authigenic quartz, that form cements or fill the veins cutting the sample material have been studied. Fluid inclusion data in quartz and carbonates result in homogenization temperatures of 74–233 °C. The Raman analysis gives temperature estimations for the organic matter of about 164 °C and 197 °C, depending on the borehole, which points to a low coalification degree. The post-sedimentary processes of compaction, cementation and diagenetic dissolution under eo- and meso-diagenetic conditions to temperatures of over 160 °C influenced the present character of the deposits. P-T conditions of brines and methane trapping have been estimated to be ~850–920 bars and 185–210 °C (vein calcite) and ~1140 bars and 220 °C (Fe-dolomite/ankerite). Therefore, locally, temperatures might have been higher (>200 °C), which may be a symptom of local regional metamorphism of a very low degree.

An integrative 3-D model of the deep lithospheric structure beneath Dolsk and Odra fault zones as a result of magnetotelluric data interpretation

SUMMARY Long-period magnetotelluric soundings were carried out in the eastern part of the Fore-Sudetic Monocline in central Europe to determine the deep geoelectrical structure. It is an important area in the contact zone of the Palaeozoic terranes of Western Europe and the Proterozoic East European Craton. The research area includes the Dolsk fault zone and the Odra fault zone, which are essential geological boundaries of a regional nature separating crustal blocks of various origins. There were conducted 51 soundings on the quasi-regular mesh 150 km in SE and 225 km in NE. The research region is highly urbanized, and hence some of the data were strongly disturbed. Careful processing of data was required, and sometimes measurements had to be repeated at other locations. The collected data allow constructing 3-D models of the electrical conductivity distribution. A parallel version of the ModEM 3-D inversion code was used for modelling. The information contained in each used transfer function was also examined by performing a separate inversion of these functions. The obtained resistivity distribution models confirm the Dolsk and Odra faults' location as postulated previously by geologists. They also show that these very deep faults are reaching the lower crust. However, they do not clearly state how far the contemporary lowering of the Baltica reaches under cover of younger Palaeozoic sediments.

EMPA, XRD, and Raman Characterization of Ag-Bearing Djurleite from the Lubin Mine, Lower Silesia, Poland

The chalcocite group minerals are widely distributed among different hydrothermally affected rocks, the oxidized zone of copper sulfide deposits, or may be even crystalline from supersaturated volcanic gases. Some of the chalcocite group minerals form the main Cu orebodies. Djurleite (Cu31S16) is a rare member of the chalcocite group, with a very complex structure. The physical and chemical similarities between all members of the group make them almost unidentifiable by macroscopic and microscopic methods. In this study, Ag-bearing djurleite from the Kupferschiefer deposits, Lower Silesia, Poland, is characterized by EMPA (Electron Microprobe Analyses), XRD (X-Ray Diffraction), and Raman spectroscopy. Djurleite from the investigated site has the following general, average chemical formula: Cu30.86Ag0.1Fe0.04S16. The Ag content is up to 0.55 wt.%, while Fe is up to 0.19 wt.%. The presence of djurleite confirms a low-temperature (~90 °C), hydrothermal origin of the Cu-Ag deposit in Kupferschiefer, which is consistent with previously studies. Moreover, the authors believe that Ag-rich djurleite may often be mistaken for Ag-rich chalcocite, which used to be one of the main Ag-bearing minerals in the orebody from the Cu-Ag deposit in the Fore-Sudetic Monocline. However, the confirmation of such a statement requires more samples, which should be studied in detail.

Time Distribution of Strong Seismic Events in the Fore-Sudetic Monocline in Context of Signals Registered by Water-Tube Gauges in Książ Geodynamic Laboratory

Changes in the stress field in Świebodzice Depression (ŚU) unit area are the reason of complex kinematics of the rock blocks consisting of rotations and horizontal/vertical displacements. The measurement system of the Geodynamic Laboratory in Książ, associated with rock blocks which are separated by faults, is a natural detector of tectonic activity. Installed in laboratory long water-tube gauges allowing to determine the functions of tectonic activity—TAF, and their derivatives. A comparison of the TAF with the seismic activity of the Fore-Sudetic Monocline showed that the strong seismic shocks (magnitude ≥3.6) occur in the Monocline only during defined and repeatable phases of the kinematic activity of the ŚU. Observed concordance proves the thesis of the existence of a large-scale, and largely homogeneous field of tectonic forces which, at the same time, cover the ŚU and the Fore-Sudetic Monocline units. The results of comparison between seismic events temporal distribution and phases of tectonic activity of the ŚU orogen indicate existence of the time relation between function of derivative of the tectonic activity (TAF) and seismic events.

The prospecting strategy for a deep Cu-Ag ore deposit in Poland – An anatomy of success

The article presents the prospecting strategy implemented by Miedzi Copper Corporation in search for new Cu-Ag ore deposits of the Kupferschiefer type. Sediment-hosted stratiform copper deposits in Poland occur mostly in the Fore-Sudetic Monocline, in the contact zone between the continental red beds (Rotliegend) and Zechstein marine sediments. The ore-bearing series consists of white sandstone (Weissliegend), copper-bearing shale (Kupferschiefer) and carbonates (Zechstein Limestone). The southern-central part of the Fore-Sudetic Monocline is a well-known Lubin-Sieroszowice mining area, where mining operations are conducted at the depths up to 1300 m below surface. However, due to significant depletion of shallower reserves, deep Cu-Ag mineralisation have recently become a subject of interest. Several basic problems had to be resolved in order to reach for such deposits: finding indicators suggesting the presence of rich mineralisation; more precise identification of the current geothermal field in the area of the Fore-Sudetic Monocline; and the availability of modern technologies which would allow safe and economic operation of a deep underground mine. In 2011, Miedzi Copper Corporation initiated its exploration programme focused on deep Cu-Ag ore deposits, based on known prognostic areas in the vicinity of palaeorises and contacts between oxidised and reduced facies, as copper mineralization occurs at the rims of oxidised areas, on the reduced side of the redox boundary. Exploration programme has led to the documentation of three new deep deposits: Nowa Sól, Sulmierzyce North and Mozów, two of which were identified in areas previously described as prospective by the Polish Geological Institute.

Characteristics of Rotliegend sediments in view of X-ray microtomohraphy and optical microscopy investigations

The article presents the results of microtomographic and petrographic investigations of Rotliegend sandstones collected from core material from wells located in the area of the Fore-Sudetic Monocline in its central and northern parts and also on the border of the Fore-Sudetic Monocline and the Mogilno - Łódź Synclinorium. Three areas were selected for the study: Czarna Wieś–Parzęczewo (19 samples), Środa Wielkopolska–Kromolice (21 samples) and Siekierki–Miłosław (21 samples). The aim of the petrologic and microtomographic studies was to investigate how the different reservoir properties of sandstones will be reflected in the results of the methods used. Strong differences between samples from the region of Środa Wielkopolska–Kromolice and the other studied areas have been demonstrated. In the case of this area several key factors were noticed: the highest average value of effective porosity; the highest average content of pores belonging to class VII (pore volume subsystem classification); three times higher average value of the CT porosity coefficient and the largest length of the average chord. Also in terms of petrography (composition of grains, cement type) it is a region where major differences, especially compared to the region of Czarna Wieś–Parzęczewo, can be seen. Based on the obtained results, it was possible to rank the examined regions in terms of their reservoir properties – from the worst (Czarna Wieś–Parzęczewo) to the best (Środa Wielkopolska–Kromolice). These conclusions are also confirmed by other petrophysical analyses (eg. mercury porosimetry, permeability analysis). Combination of the obtained microtomographic and petrographic results allowed to obtain a full characterization of the investigated samples – both in terms of the mineralogical composition of grains, as well as the development of the pore space. These data, especially in combination with the results of density and porosity analyses (helium pycnometry and mercury porosimetry), open up a number of possibilities to carry out different types of modeling (porosity, permeability) both on the scale of the sample itself, as well as the scale of a single well or even the whole basin, which is crucial for creating a hydrocarbon exploration strategy.

Lichens Bite the Dust - A Bioweathering Scenario in the Atacama Desert.

SummaryBioweathering mediated by microorganisms plays a significant role in biogeochemical cycles on global scales over geological timescales. Single processes induced by specific taxa have been described but could rarely be demonstrated for complex communities that dominate whole landscapes. The recently discovered grit crust of the coastal Atacama Desert, which is a transitional community between a cryptogamic ground cover and a rock-bound lithic assemblage, offers the unique chance to elucidate various bioweathering processes that occur simultaneously. Here, we present a bioweathering scenario of this biocenosis including processes such as penetration of the lithomatrix, microbial responses to wet-dry cycles, alkalinolysis, enzyme activity, and mineral re-localization. Frequently occurring fog, for example, led to a volume increase of microorganisms and the lithomatrix. This, together with pH shifts and dust accumulation, consequently results in biophysical breakdown and the formation of a terrestrial protopedon, an initial stage of pedogenesis fueled by the grit crust.