Intra-Sudetic Basin Research Articles

Development of a non-perennial to ephemeral fluvial system in a continental fault-bounded basin – an example from the early Permian Krajanów Formation of the Intra-Sudetic Basin (NE Bohemian Massif) – discussion

Development of a non-perennial to ephemeral fluvial system in a continental fault-bounded basin – an example from the early Permian Krajanów Formation of the Intra-Sudetic Basin (NE Bohemian Massif) – discussion

A new early Permian actinopterygian assemblage shows environmental controls on the distribution of Paramblypterus (Intra-Sudetic Basin, Poland)

A new early Permian actinopterygian assemblage shows environmental controls on the distribution of Paramblypterus (Intra-Sudetic Basin, Poland)

Influence of Late Carboniferous–Early Permian climate change on the sedimentary evolution – a case study of the lacustrine Lower Anthracosia Shales (Intra-Sudetic Basin, SW Poland)

The Anthracosia Shales are lacustrine deposits within the volcano-sedimentary Pennsylvanian– Lower Permian succession of the Intra-Sudetic Basin. Core from the Rybnica Leśna PIG 1 borehole, which penetrated the Lower Anthracosia Shales, was analysed to explore the influence of climate on the evolution of the palaeolake, as distinct from tectonic and volcanic forcing. This reconstruction was made using mineralogical and geochemical proxies (elemental and mineralogical composition, TOC values, presence of framboidal pyrite and siderite). Based on the results, three chemically different intervals previously introduced by Wójcik-Tabol et al. (2021) are described. They represent the following stages of lake evolution: transgression (interval I), open lake (interval IIA and IIB), and termination (interval IIC and III). The initial stage of the lake (interval I) was probably related to a rise in humidity in the Late Pennsylvanian, linked to a southern Gondwana interglacial episode. Interval IIA represents the deepest facies of the Anthracosia Basin, where lake-floor anoxia prevailed. This stage was followed by a gradual lake-level fall recorded in interval IIB, with documented seasonality in humid and warm conditions. Interval IIC represents a stepwise lake regression attributed to aridification, as indicated by proxies showing a decrease in chemical weathering. Turbiditic sandy laminae in interval III reflect the terminal stage of lake infill.

Development of a non-perennial to ephemeral fluvial system in continental fault-bounded basin – an example from the early Permian Krajanów Formation of the Intra-Sudetic Basin (NE Bohemian Massif)

Development of a non-perennial to ephemeral fluvial system in continental fault-bounded basin – an example from the early Permian Krajanów Formation of the Intra-Sudetic Basin (NE Bohemian Massif)

The Anthracosia Shales from the Intra-Sudetic Basin in the light of organic geochemistry proxies – preliminary results of bitumen study

The Anthracosia Shales from the Intra-Sudetic Basin in the light of organic geochemistry proxies – preliminary results of bitumen study

Petrographic, palynological and geochemical recognition of dispersed organic matter in the black Anthracosia Shales (Sudetes, south-west Poland)

We describe the organic petrography, palynology and Rock-Eval pyrolysis values of lacustrine black shales termed the Anthracosia Shales (Upper Carboniferous/Lower Permian) in the Intrasudetic Basin (Sudetes, SW Poland). Samples were taken from cores of two boreholes: Rybnica Leśna PIG 1 and Ścinawka Średnia PIG 1. Maceral composition, miospore assemblage composition, palynofacies and geochemical characteristics of dispersed organic matter in the Anthracosia Shales were used to determine conditions of the environment and to evaluate their petroleum potential. Data from both organic petrography and palynology analyses enabled recognition of three broadly distinct organic associations in these shales: bituminous, humic, and intermediate, while Rock-Eval pyrolysis revealed the presence of bituminous and humic kerogen types I and III. Type I corresponds to the bituminous association, with amorphous organic matter (AOM) dominant in the palynofacies, and type III corresponds to the humic association with phytoclasts prevailing in the palynofacies. The thermal maturity of the organic matter is determined by the values of: (1) vitrinite reflectance V Ro = 0.53–0.73%, (2) palynomorph 3–4 colour index, and (3) T max = 443–447°C, which indicate oil window maturity. Some of the TOC results (1.6–2.9 wt.%) indicate that the Anthracosia Shales are good and very good petroleum source rocks, though the thickness of this interval is low (4–5 m). Shales with TOC values <0.5 wt.% prevail, and may be classifed as poor source rocks.

Revision of the Pennsylvanian fern Senftenbergia elegans Corda from the Duckmantian of the Intra- Sudetic Basin, Czech Republic

Adpression specimens of fertile pinnae of Senftenbergia elegans from the Corda's type collection have been studied in detail for the first time. The specimens come from the Žďárky locality near Náchod, Intra-Sudetic Basin, Duckmantian, Czech Republic. The study shows that Senftenbergia elegans has a unique type of in situ spores, different from the other Senftenbergia-like ferns, although they all belong to the Tedelaceae.

Polyphase Permo-Carboniferous magmatism adjacent to the Intra-Sudetic Fault: constraints from U–Pb SHRIMP zircon study of felsic subvolcanic intrusions in the Intra-Sudetic Basin, SW Poland

The SHRIMP U–Pb dating of zircons from felsic subvolcanic rocks in the Carboniferous formations of the Intra-Sudetic Basin in SW Poland verifies previous views on the timing of Late Palaeozoic magmatic activity in this area and constrains the links between regional tectonics and intra-basinal volcanism in the mid-European Variscides. Two main stages of magmatism are identified: the Late Carboniferous late orogenic stage, and the Early Permian post-orogenic stage. The Carboniferous late orogenic subvolcanic to volcanic activity was contemporaneous with the formation of the Karkonosze granite pluton to the west and comprised episodic emplacement of predominantly felsic laccoliths and sills within the basin fill during the Westphalian–Stephanian in two sub-stages at ca. 313–310 Ma and 306–305 Ma. Local folding of the Carboniferous succession peaked at ca. 303–300 Ma adjacent to the Intra-Sudetic Fault, in relation to late-stage sinistral movements along this regional wrench fault. The emplacement of minor subvolcanic intrusions at ca. 293 Ma completed the activity in the northern Intra-Sudetic Basin; this Permian post-orogenic volcanism, however, developed fully in areas further south. The predominance of subvolcanic intrusions over extrusions in Carboniferous can be linked to the trapping of rising magmas within the several kilometres thick sedimentary basin fill. Zircon xenocrysts in the Carboniferous subvolcanic rocks indicate that older crustal lithologies, possibly metamagmatic and metasedimentary rocks of dominantly Neoproterozoic–Palaeozoic ages, were involved in petrogenesis as magma sources and/or contaminants. The crustal influence on magma formation was stronger during the earlier magmatic events.

Origin and timing of spilitic alterations in volcanic rocks from Głuszyca Górna in the Intra-Sudetic Basin, Poland

The formation of spilitic assemblages (i.e. chlorite and albite) has been ubiquitously involved during the evolution of continental early-Permian volcanics from the Intra-Sudetic Basin (ISB). Based on the investigation of laccolith-type and variably-altered trachyandesite exposure in the vicinity of Głuszyca Górna (Lower Silesia, Poland), we have demonstrated that apatite fission-track dating (AFT), coupled with chlorite geothermometry, can be successfully applied to denote the timing of low-temperature alterations within volcanic rocks. The primary magmatic assemblages of the trachyandesites (i.e. augite and andesine-labradorite) have been affected by chloritization and alblitization respectively, followed by the formation of secondary titanite, celadonite, and calcite. The chlorite species have crystallized in the range of 106–170 °C, that exceeds Apatite Partial Annealing Zone (70–110 °C). The secondary, nearly pure albite (Ab ~ 99 mol.%) with weak to dark-brown cathodoluminescence replaces primary plagioclase (~ An37–50Ab47–58Or2–4) along the cleavage and/or twinning planes during Al3+–conservative reaction. The accessory apatite is marked by swallow-tail terminations indicative of rapid cooling formation conditions. It shows homogenous chemical composition, high F− content, and pink to yellow (REE3+ and Mn2+-activated, respectively) cathodoluminescence. Based on the AFT dating, the development of spilitic alterations within the early-Permian (ca 290 Ma) laccolith from Głuszyca could not only span the range of 182–161 Ma (Middle Jurassic), but also occurred prior to large-scale geological events in the ISB, such as burial under late-Mesozoic sediments, as well as tectonic inversion and exhumation. Whole-rock geochemistry of trachyandesites altered to various extent, indicates that original trace elements concentrations, except for i.e. Sr, Cs, and Ba, could be preserved during low-temperature alteration (spilitization). Meanwhile, geochemical fingerprint of the volcanics (i.e. humped-shaped mantle normalized trace element diagrams and positive Zr–Hf anomaly) points to the crustal contamination during magma evolution, combined with the mantle metasomatism in the source via subduction-derived components (i.e. fluids), as shown by i.e. low Nb/Th and Nb/LREE ratios.

The New flora from the Permian of the Intrasudetic Basin, Poland

A floral assemblage was collected from a new Polish locality (Janików) situated on the Czech- Polish border in the Intrasudetic Basin. It was found in the lower Permian (Asselian) Ruprechtice Horizon, of the Olivětín Member, Broumov Formation. The plant fossils were usually fragmentary, and the following taxa were determined: Alloiopteris aff. erosa, Nemejcopteris feminaeformis, Senftenbergia sp., Lobatopteris sp., Sphenopteris sp., Cyathocarpus cf. densifolius, Lobatopteris cf. geinitzii, Lobatopteris nov. sp., Dicksoniites cf. plukenetii, Autunia conferta, Cordaites sp. and seeds. Alloiopteris was first recorded in the Permian. The assemblage is composed predominantly of ferns and pteridosperms that tend to be hygrophilous to mesophilous floral elements. The flora from the Otovice and Ruprechtice horizons is usually rich in walchian conifers and peltasperms (Autunia conferta), and so the Janików flora is quite different with its hygrophilous elements. The fragmentary preservation suggests long transport distances, and probably only the remains of flora growing on the lakeshore were deposited in the calcareous bituminous shales. This coastal vegetation probably formed a barrier to mesophilous plants growing further from the lake, so their fragments are more sporadic.

Macroflora of the Krkonoše-Piedmont Basin (Pennsylvanian–early Permian); Bohemian Massif, Czech Republic

The Krkonoše-Piedmont Basin is one of several land-locked post-collisional Variscan basins of the Bohemian Massif. The fossil record of the basin is evaluated, based on published data and unpublished lists of floras collected in borehole cores and during mapping. The occurrence ranges of plant taxa are plotted against radioisotopically calibrated lithostratigraphic units. The compiled dataset is used to evaluate species richness and vegetation patterns throughout Late Pennsylvanian and Asselian times. The species richness of particular intervals has been affected by taphonomic and sampling biases of varying intensities. Coal-bearing strata and grey lacustrine intervals represent well-documented fossil-rich taphonomic windows with 20–45 species. In contrast, red beds are fossil-poor and under-sampled, typically providing only a few species. It is assumed that coal-bearing and grey lacustrine intervals represent periods of increased climatic humidity, during which wetlands covered extensive areas of basinal lowlands or shallows and coastal areas of meromictic lakes. Most habitats were colonised by hygrophytes and mesophytes. However, sparse conifer shoots found in association with wetland taxa indicate seasonality to a sufficient degree that xerophytic taxa were able to get close to sites of deposition and wetland habitats. During the deposition of red beds, wetlands may have almost completely disappeared, resulting in the basinal landscape being colonised by gymnosperm-dominated forests of walchian conifers with co-dominant cordaitaleans. Wetland assemblages of low diversity and small populations may have survived in the basin, although many species may have disappeared from the basin, having dispersed elsewhere to habitats where their survival was possible. In the late Middle Pennsylvanian and early Upper Pennsylvanian, such habitats existed in the Intra-Sudetic Basin farther east, and in other basins located in western and central parts of the Bohemian Massif. These climatically-driven oscillations in vegetation patterns, which occurred on scales of hundreds of thousands to a million years, were superimposed on a long-term drying trend marked by an increase in gymnosperms in the species pool, as well as an abundance of their remains in the fossil record, at the expense of free-sporing plants. Among the gymnosperms, there was a gradual drop in the diversity and abundance of medullosalean pteridosperms and a concomitant rise of peltasperms and conifers.

Radvaniceite, GeS2, a New Germanium Sulphide, from the Kateřina Mine, Radvanice near Trutnov, Czech Republic

The new mineral radvaniceite, GeS2, was found on the burning coal mine dump of the abandoned Kateřina coal mine at Radvanice, near Trutnov, northern Bohemia, Czech Republic. It occurs as aggregates resembling cotton tufts up to 5 mm in size; they are composed of acicular crystals up to fibres about 1–5 μm thick and up to 3 mm in length. Individual fibres are distorted and partly resemble bent wires nucleated on rock fragments or on black, crumbly ash, in association with minerals of solid solutions of Bi-Sb and stangersite, herzenbergite, and greenockite. Radvaniceite was also observed as irregular grains in a range of 10–50 μm in size, forming part of earlier multicomponent aggregates upon which the above-described crystals grow. These aggregates are formed, in addition to radvaniceite, by minerals of Bi-Sb, Bi2S3-Sb2S3 and Bi2S3-Bi2Se3 solid solutions, Bi3S2, Bi-sulpho/seleno/tellurides, tellurium, unnamed PbGeS3, Cd4GeS6, GeAsS, Sn5Sb3S7, stangersite, greenockite, cadmoindite, herzenbergite, teallite, and Sn- and/or Se-bearing galena. Radvaniceite is formed under reducing conditions by direct crystallization from hot gasses (250–350 °C) containing Cl and F at a depth of 30–60 cm under the surface of a burning coal mine dump; the mine dump fire started spontaneously, and no anthropogenic material was deposited there. Acicular crystals up to fibres of radvaniceite are elastic to flexible; are white to yellowish grey in colour, with white streaks; are translucent in transmitted light; and have vitreous to adamantine lustre. Cleavage and fracture were not observed. The calculated density is 3.05 and 2.99 g·cm−3 for the empirical and ideal formulae, respectively. Radvaniceite is transparent under the microscope, with a very weak pleochroism (from colourless to pale greenish yellow), and has a refraction index > 1.8. Under reflected light, radvaniceite is light grey; bireflectance and pleochroism were not observed due to abundant, white to grey, internal reflections. Anisotropy in crossed polars is distinct with grey rotation tints. Reflectance values of radvaniceite in air (Rmin–Rmax, %) are: 15.4–18.8 at 470 nm, 16.1–20.4 at 546 nm, 16.4–20.8 at 589 nm, and 16.9–20.9 at 650 nm. The empirical formula, based on electron-microprobe analyses, is (Ge0.99Bi0.01)Σ1.00(S1.97Se0.03)Σ2.00. The ideal formula is GeS2, which requires Ge 53.10, S 46.90, total 100 wt. %. Radvaniceite is monoclinic, Pc, a = 6.8831(12), b = 22.501(3), c = 6.8081(11) Å, β = 120.365(9)°, with V = 909.8(4) Å3 and Z = 12. The strongest reflections of the powder X-ray diffraction pattern [d, Å (I) (hkl)] are: 5.7395 (100) (11-1, 110), 5.2067 (16) (021), 3.3650 (33) (111, 11-2), 2.8417 (33) (022), 2.8236 (16) (170, 17-1), 2.8134 (20) (080) and 2.6257 (19) (240, 24-2). According to X-ray powder diffraction data and Raman spectroscopy, radvaniceite is a natural analogue of synthetic monoclinic low-temperature β-GeS2 with distorted GeS4 tetrahedra forming four corner-sharing tetrahedral chains, which are connected by corner-sharing tetrahedra in a three-dimensional structure. We named the mineral after its type locality, Radvanice, one of the past centres of coal mining in the Czech limb of the Intra-Sudetic Basin. This mineral and its name have been approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association (number 2021-052).

Early Pennsylvanian to early Permian (Bashkirian-Asselian) miospore and pollen assemblages of the Czech part of the Intra-Sudetic Basin

Early Pennsylvanian to early Permian (Bashkirian-Asselian) miospore and pollen assemblages of the Czech part of the Intra-Sudetic Basin

Age revision of Carboniferous rocks in the northern part of the Intra-Sudetic Basin (SW Poland) based on miospore data

Palynostratigraphic studies of the Carboniferous strata of the Szczawno and Walbrzych formations, outcropping in the vicinity of Walbrzych in the northern part of the Intra-Sudetic Basin, are reported. Rocks of the Szczawno Formation in a section near Konradow had earlier been assigned to the Upper Visean, while rocks of the Walbrzych Formation in the Bialy Kamien section were included to the Lower Namurian [the Stenozonotriletes triangulus – Rotaspora knoxi (TK) Miospore Zone]. This study describes abundant palynological material with many taxonomically diverse miospore assemblages from these rocks, allowing precise palynostratigraphic conclusions. These showed that the rocks of the Szczawno Formation studied should be referred to the lower part of the Serpukhovian [ Verrucosisporites morulatus (Vm) Subzone], correlated with the lowest Namurian, while rocks of the Walbrzych Formation from Bialy Kamien belong to the Lower Bashkirian [ Lycospora subtriquetra–Cirratriradites rarus (SR) Subzone], correlated with the Upper Namurian A. These results indicate that the rocks from both sections studied are younger than they were earlier believed. This revises the age of the Szczawno and Walbrzych formations in the northern part of the Intra-Sudetic Basin which belong to four miospore zones, from Vm to SR, corresponding to the Serpukhovian and lowermost Bashkirian (Namurian A corresponding to the Pendleian to Alportian of British chronostratigraphy).

Actinopterygians of the Broumov Formation (Permian) in the Czech part of the Intra-Sudetic Basin (the Czech Republic)

Actinopterygians from the Permian sediments of the Czech part of Intra-Sudetic Basin, occurring in the Ruprechtice and Otovice Limestone horizons (Broumov Formation), are revised and redescribed based on both old material and newly discovered specimens. A new diagnosis and reconstruction of Paramblypterus vratislaviensis (Agassiz, 1833), the most numerous actinopterygian of the Ruprechtice Limestone Horizon, and the rare Paramblypterus zeidleri (Fritsch, 1895) are published. First actinopterygians from the Otovice Limestone Horizon were described. Most of the specimens from the Otovice Limestone are referred here to Paramblypterus cf. rohani and Paramblypterus sp. Representatives of Aeduellidae have also recently been discovered in the Otovice Limestone. Osteological fragments belonging to a new taxon exhibit the diagnostic features of the genera Aeduella and Bourbonnela. The reasons for the significantly different faunistic content in the stratigraphically close Ruprechtice Limestone Horizon and Otovice Limestone Horizon are discussed.

Burial and thermal history of the Intra-Sudetic Basin (SW Poland) constrained by 1-D maturity modelling - implications for coalification and natural gas generation

Burial and thermal history of the Intra-Sudetic Basin (SW Poland) constrained by 1-D maturity modelling - implications for coalification and natural gas generation

Evidence of Carboniferous volcanic activity in deposits of the Petrovice Member in Czech part of the Intra-Sudetic Basin near Debrné

Evidence of Carboniferous volcanic activity in deposits of the Petrovice Member in Czech part of the Intra-Sudetic Basin near Debrné

Thermal history of the Carboniferous strata in the northern part of the Intra-Sudetic Basin (SW Poland): A combined Raman spectroscopy and organic petrography study

Raman spectroscopy and vitrinite reflectance measurements of dispersed organic matter from Carboniferous shales in boreholes in the northern part of the Intra-Sudetic Basin were used for thermal history reconstruction. Microscopic investigations have shown that the organic matter is dominated by the vitrinite maceral group. In analysed samples, organic matter shows a varied degree of thermal alteration determined by the mean random vitrinite reflectance (VRo) ranging from 0.72% to 3.80%. Mean apparent maximum vitrinite reflectance (R’max) values reached 4.98%. The full width at half maximum of D1 and G bands in Raman spectra are well-correlated with mean VRo and R’max. Thermal maturity in the boreholes shows a regular increase with depth. Geological data combined with Raman spectroscopy and mean vitrinite reflectance results indicate that the analysed Carboniferous strata reached maximum paleotemperatures from c. 110 to c. 265°C. The regional paleogeothermal gradient in the late Paleozoic was c. 80°C/km. The Variscan heating event presumably caused a major coalification process of organic matter. The Carboniferous–Permian magmatic activity must have contributed to high heat flow, adding to the effect of sedimentary burial on the thermal maturity.

Zircon U-Pb Dating of Magmatism and Mineralizing Hydrothermal Activity in the Variscan Karkonosze Massif and Its Eastern Metamorphic Cover (SW Poland)

SHRIMP (Sensitive high resolution ion microprobe) zircon U-Pb dating of the two main igneous rocks types in the Karkonosze Pluton, porphyritic and equigranular monzogranite, yield 206Pb/238U ages between 312.0 ± 2.9 and 306.9 ± 3.0 Ma. These coincide, within uncertainty, with the majority of previous dates from the pluton, which indicate development of the main magmatic processes between ca. 315 and 303 Ma. They also coincide with molybdenite and sulfide Re-Os ages from ore deposits developed during magmatic and pneumatolitic-hydrothermal (e.g., Szklarska Poręba Huta and Michałowice) or/and metasomatic and hydrothermal (e.g., Kowary, Czarnów and Miedzianka) processes forming Mo-W-Sn-Fe-Cu-As-REE-Y-Nb-Th-U mineralization. The 206Pb/238U zircon age of 300.7 ± 2.4 Ma from a rhyolite porphyry dyke (with disseminated base metal sulfide mineralization) in the Miedzianka Cu-(U) deposit coincides with the development of regional tectonic processes along the Intra-Sudetic Fault. Moreover, at the end-Carboniferous, transition from a collisional to within-plate tectonic setting in the central part of the European Variscides introduced volcanism in the Intra-Sudetic Basin. Together, these processes produced brecciation of older ore mineralization, as well as metal remobilization and deposition of younger medium- and low-temperature hydrothermal mineralization (mainly Cu-Fe-Zn-Pb-Ag-Au-Bi-Se, and Th-U), which became superimposed on earlier high-temperature Mo-W-Sn- Fe-As-Cu-REE mineralization. A few 206Pb/238U ages > 320 Ma remain to be reconciled, but might be due to the high U and Th contents of the zircon and the strong influence of overprinting pneumatolitic-hydrothermal processes.

Adpression of medullosan prepollen-producing organs, their prepollen and cuticles (Westphalian, Intrasudetic Basin, Czech Republic)

The adpression fossil record from the Westphalian of the Intrasudetic Basin (Czech Republic) contains diversified medullosan prepollen organs. Langsettian bell-shaped prepollen organs were found in the Lampertice Member in the Žacléř area: Whittleseya elegans Newberry, W. delphinae Stockmans et Willière, W. silesiaca Pacyna et Zdebska and Givesia media (Stockmans) Stockmans et Willière. These fructifications may have been produced by plants with fronds of the fossil-genera Neuralethopteris Cremer and Alethopteris Sternberg. Parent plants of small Langsettian Aulacotheca sp. are uncertain. Duckmantian medullosan male fructifications from the Malé Svatoňovice area are elongated capsules described as Aulacotheca idae Šimůnek sp. nov. and were produced by plants with Alethopteris idae Šimůnek fronds. The prepollen grains and cuticles were isolated from Whittleseya elegans, W. delphinae, Givesia media and Aulacotheca idae. All prepollen grains are oval with two longitudinal grooves and a monolete suture, and are classified as Monoletes ovatus Schopf. There is great overlap in the dimensions of the prepollen of Whittleseya elegans, W. delphinae and Givesia media – 155–230 μm long and 100–180 μm wide. Prepollen of Aulacotheca idae are much bigger – 330–375 μm long and 190–245 μm wide. The inner cuticular layer is gently cutinised with polygonal cells. Cuticles from the prepollen organ surface has elongated cells in Whittleseya elegans (with stomata) and Givesia media (with trichome bases), and has polygonal cells in Whittleseya delphinae (with periclinal cell wall thickenings) and Aulacotheca idae (with hollow papillae on periclinal cell walls). The question, as to whether Whittleseya elegans and W. delphinae are conspecific is discussed.