Geological Quarterly

Tectonic geomorphology of the Hoyran Graben (Western Anatolia, Türkiye): insights from geomorphic indices

2024-04-25T14:08:51+00:00

The area between Western Anatolia and Isparta Bend comprises numerous depressions and the active faults that bound them. The Hoyran Graben is one of these depressions, located at the northernmost part of the Isparta Bend. This NE–SW-oriented graben is bounded by the Hoyran Fault in the northwest and the Uluborlu, Senirkent and Kumdanlı faults in the southeast, respectively. We evaluate the seismic activity potential among segments of the boundary faults in the light of fieldwork and morphometric indices. These boundary faults of the Hoyran Graben are divided into twelve segments for the analysis, with indices used including mountain-front sinuosity (Smf: 1.05–2.02), valley floor width-to-valley height ratio (Vf: 0.11–1.34), hypsometric curve and its integral (Hi: 0.4–0.73), asymmetry factor (Af: 13.76–87.03), stream length-gradient (SL: 1.48–9450) and normalized channel steepness (Ksn: 2.38–990.38). The results obtained, together with field observations, indicate that the Uluborlu, Senirkent and Kumdanlı faults, as well as the western segments of the Hoyran Fault, represent higher potential in terms of seismic activity with uplift rates >0.5 mm/y, while the central and eastern segments show moderate activity with uplift rates between 0.05 and 0.5 mm/y. Thus, the boundary faults of the Hoyran Graben need further attention in terms of regional seismic hazard.

Pomerania Gravity Low at the East European Craton margin – granitic batholith or a Paleoproterozoic impact structure ?

2024-04-25T14:09:42+00:00

The Pomerania Gravity Low is a regular large-amplitude, oval-shaped anomaly of a disputable origin located at the East European Craton margin. In the past it was interpreted as a Proterozoic crustal keel or Early Paleozoic/Permian-Mesozoic depocenter. The origin of the anomaly has been reconsidered based on a reinterpretation of previous potential fields, seismic and magnetotelluric data and recent gravimetric modelling results. New alternative interpretations are proposed and discussed: felsic intrusion related to the Transscandinavian Igneous Belt and a large impact structure ca. 1.6-1.8 Ga old. In view of the presented data and regional comparisons the impact origin seems more probable. Nevertheless, a prolonged erosion, deep burial and metamorphic overprint hamper verification of this hypothesis, e.g. by finding impact ejecta or shock-affected minerals.

Post-mining deformations in the area affected by the former ”Siersza” Hard Coal Mine in Trzebinia (southern Poland)

2024-04-25T14:10:15+00:00

Over the recent years, post-mining terrain deformations have been increasingly frequent around Trzebinia. Sinkholes appearing closer and closer to buildings have become a significant geohazard. The research demonstrated that the problem of post-mining deformation in the area is much more extensive than previously estimated. Identification of the deformations involved analysis of historic aerial photographs, airborne laser scanning data, orthophotomaps and satellite radar data. Moreover, laser scanning of the selected areas using an unmanned aerial vehicle and a terrestrial laser scanner was carried out together with field mapping work. A comprehensive survey of sinkholes, including those previously unknown – located outside built-up areas – allowed an assumption to be made that areas where sinkholes had been remediated in the past were also at significant risk. A number of sinkholes are also located outside areas of shallow mining (up to 100 m below ground level). In the study area, 527 sinkholes and 254 linear-type deformations (post-mining faults) were identified. The use of satellite radar interferometry made it possible to state that continuous deformations also occur in the area of influence of the former "Siersza" Hard Coal Mine. In the past, this was the subsidence of the terrain, and currently an uplift is faced in this area which, in some places, reaches up to 20 mm per year.

A first record of alluvial gold in the Olănești and Cheia rivers, Southern Carpathians, Romania

2024-04-25T14:10:19+00:00

We provide the first scientific record and the mineralogical characterization of alluvial gold in the Olănești area, Southern Carpathians, Romania, based on field evidence, optical microscopy, and XRD, BSE and EPMA data. Chemical data were acquired on 11 alluvial gold grains from the Olănești and Cheia rivers and revealed a generally continuous variation in gold and silver content with Ag ranging from 7.31 to 19.77 wt.% and Au ranging from 80.26 to 93.16 wt.%. The source of the primary native gold is inferred to be the Cu-Au Valea lui Stan and/or the Costești As-Au shear-zone-related ore deposits located towards the north and west, respectively, of the study area.

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)

2024-04-25T14:10:29+00:00

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.

An attempt to explain the disappearance and decline in discharge rate of selected karst springs of the Opole region.

2024-04-25T14:10:51+00:00

Significant discharge changes of karst springs, to the point of their disappearance, prompt research into the causes as related both to climate change and to human-induced factors. This analysis uses climate data from the last 70 years, publications from the beginning of the 20th century, biennial measurements of the discharge rate of six selected springs over the last 40 years, and considerations of mine drainage. An increase in average air temperature by 1.5°C in the last 30 years, a slight decrease in precipitation and an almost quadrupled increase in groundwater extraction in mines were recognised. Such a significant increase in mine-related groundwater extraction significantly affects the springs’ discharge rate and the river network. Significant mine drainage and groundwater extraction are causing deleterious changes to previously good-quality groundwater.

The Badenian/Sarmatian (Middle Miocene) boundary in the Central Paratethys (Kreminna, western Ukraine): Foraminiferal and palynological evidence

2024-04-25T14:11:04+00:00

The Badenian/Sarmatian boundary in the Paratethys basin, that marks the transition from normal marine to restricted semi-marine conditions due to isolation of the basin from the world ocean at the onset of Sarmatian time, is still far from being fully understood. The Kreminna section is located at the northeastern margin of the Carpathian Foreland Basin (Central Paratethys) in the Medobory Hills region. The Miocene deposits that overlie here the Upper Cretaceous substratum comprise the >1 m thick upper Badenian marls and clays passing upwards into ~4 m thick Sarmatian marly limestones with intercalations of marls, clays and limestones, and >2 m thick limestones in the uppermost part of the exposure. Fifty-three species of benthic foraminifera and four species of planktonic foraminifera have been recorded. Six benthic foraminiferal assemblages are composed almost exclusively of calcareous forms; agglutinated taxa are practically lacking. Elphidium spp., miliolids, Lobatula lobatula and Ammonia spp. are the most common calcareous benthic foraminifera in the material studied. Planktonic foraminifera are represented only by species of Globigerina and occur rarely in the lowermost part of the section. A characteristic feature of palynofacies is the very low proportion of land-derived elements – sporomorphs and cuticles, which suggests a sedimentary setting without terrestrial influx, and taxonomical impoverishment of dinoflagellate cyst assemblages, which are either monospecific or consist mainly of two to three species: in a majority of samples, assemblages with Polysphaeridium zoharyi and P. subtile occur. Most δ¹⁸O values range from –1.5 to ~+0.5‰ VPDB and most δ¹³C values are between 0 and +2‰ VPDB. In general, the δ¹³C curve mirrors the δ¹⁸O changes in the section. The Badenian/Sarmatian boundary is placed at the level where the Cibicidoides ungerianus Assemblage is replaced by the Elphidium fichtelianum Assemblage. At the boundary, planktonic foraminifers and most abundant stenohaline benthic foraminifera disappeared. Bottom waters were well-oxygenated both in the latest Badenian and earliest Sarmatian in the Kreminna location.

Assessment of arsenic and toxic metal contamination in soils, pore waters and plants surrounding a historical mine site in Czarnów (SW Poland)

2024-04-25T14:11:05+00:00

Centuries of gold-arsenic ore mining activities in Czarnów village within the Evelinens glück mine (SW Poland) have left an enduring impact on the local environment, characterized by distinct geochemical anomalies and contamination in water and plants. We have comprehensively investigated the spatial distribution of arsenic and metals in soils, plants, and water in close proximity to post-mining dump sites. The findings reveal striking anomalies in the vicinity of the mine, notably elevated levels of arsenic, zinc, lead, copper and cobalt. The highest recorded arsenic content surpassed 290,000 ppm, with cobalt reaching almost 18,000 ppm and copper exceeding 21,000 ppm. This contamination was most pronounced around mining excavations and in the immediate vicinity of mining dumps. Additionally, pore water analysis from the study area uncovered elevated arsenic levels, surpassing permissible standards, with concentrations exceeding 600 ppb. Moreover, plant specimens (Rubus idaeus, Deschampsia flexuosa, Dryopteris carthusiana) in the region were observed to accumulate arsenic and other toxic elements, with Rubus idaeus recording the highest arsenic concentration at 19.00 ppm. These accumulations consistently exceeded established environmental norms. The presence of such elevated concentrations of toxic elements in both soil and plant life underscores profound concerns for human health, with potential implications for a range of health issues.

New insight into coastal processes in the southern Baltic Sea: relevance to modelling and future scenarios

2024-04-25T14:11:07+00:00

Understanding the relationships between shoreline changes and morpho-geological features of the seabed and hydrodynamics is important for predicting coastal dynamics. The southern Baltic barrier coast is distinguished by rhythmic shoreline features of different scales, forming an erosion-accumulation system. This study is an attempt to explain the relationships between shoreface-connected, obliquely oriented sand ridges, the distribution of wave energy, and the impact of waves on shoreline changes. A 28.5 km stretch of the Polish coast, up to 2 km offshore, was investigated using a multibeam echosounder, a sub-bottom profiler, a side-scan sonar, and sediment coring. Analyses of a DTM, aerial photographs and maps from the late 19th century show that the boundaries between accretion and erosion zones on the coast have shifted eastward at a rate of ~10–11 m/year. Hydrodynamic modeling shows that depressions between the ridges are “energy windows” through which higher energy waves reach the shore. The asymmetry of the ridges and their orientation relative to the prevailing direction of waves suggest that they have been moving eastward. Measurements of ¹³⁷Cs content in the sediment cores prove that the thickness of the dynamic layer exceeds 1.5–2.0 m. When large-scale sand ridges migrate, “energy windows” also migrate with them, as does the entire erosion-accretion system. In conclusion, it is highly likely that the average shoreline retreat measured on the scale of a few centuries and dozens of kilometres may be smaller than we suspect based on observations made in recent decades.

Geological features of the Zn-Pb prospect in the Bou-Izourane district (Morocco)

2024-04-25T14:11:16+00:00

The Zn-Pb mineralization in the Bou-Izourane district, located in the High Atlas Mountains of Morocco, contains estimated reserves of 40 200 tons of ore with an average grade of 20% Zn and 3.5% Pb. It is developed on N–S to NNW–SSE-trending faults that cut Liassic carbonate marl deposits. The paragenetic mineral sequence consists of galena, sphalerite and late-stage calcite. Oxidation phases of galena into cerussite and sphalerite into smithsonite are common in the Bou-Izourane ore, linked to the infiltration of meteoric waters and the oxidation of these sulphides. The Zn-Pb mineralization runs parallel to the fluorite veins associated with the igneous rocks of Tamazeght, but no petrographic or field relationship has been demonstrated between these two mineralizations (i.e., Zn-Pb and fluorite). The distribution of rare earth elements and yttrium (REY) in the Zn-Pb mineralization of Bou-Izourane shows a notable similarity with the Mississippi Valley Type (MVT) mineralization of the Central High Atlas of Morocco, although the concentrations more closely resemble those of REY in fluorite linked to the magmatic-hydrothermal activity of Tamazeght. However, the analysis of their distribution in post-fluorite calcite and post-Zn-Pb calcite reveals a strong concordance, suggesting that these two calcites are associated with the same phase and have a common origin. The classification of the Zn-Pb prospect in Bou-Izourane remains controversial, fluctuating between an MVT-type mineralization, similar to most Zn-Pb mineralizations in the Central High Atlas of Morocco, and a mineralization linked to the magmatic-hydrothermal activity of Tamazeght, which could provide heat and metallogenic material. Characterizing the Zn-Pb ore of Bou-Izourane is crucial for the future exploration of zinc and lead deposits in the High Atlas of Morocco and could advance the development of Zn-Pb mining in the region, from artisanal exploitation to professional mining

Genetic relationship of minerals to fluid circulation in the Polish Carpathians – the Bystre Slice case study

2024-04-25T14:12:08+00:00

Fieldwork conducted in the area of the Bystre Slice of the Polish Carpathians has allowed the recognition and mapping of mineral assemblages with respect to a mélange zone. Ore mineralization in the Cretaceous and Paleogene zones of the Bystre Slice, analyzed geochemically, petrographically and mineralogically, includes epigenetic minerals such as realgar, orpiment and cinnabar, here characterized and their parageneses described. Fluid inclusions are distinguished in newly discovered realgar crystals, and microthermometric results allow a mineralogical sequence in the study area to be proposed. The new mineral goyazite, previously not described in the Carpathians, occurs as solid inclusions in the realgar crystals, co-occurring with kaolinite. The mineralization likely relates to a magmatic anomaly present in the NE part of Slovakia in the Western Carpathians south of Dukla in Poland, and a possible sub-surface subvolcanic body that deepens towards the E, the inferred top of which lies at a depth of ~1 km. The mineralization may be connected with dislocations in the rock units.