Geoscience Research Reports最新文献

{"title":"Lithology and paleosols of the Klikov Formation in the borehole 2140 01T1 Dunajovice, Třeboň Basin","authors":"R. Lojka","doi":"10.3140/zpravy.geol.2022.14","DOIUrl":"https://doi.org/10.3140/zpravy.geol.2022.14","url":null,"abstract":"The 2140 01T1 borehole sampling the Late Cretaceous non-marine strata of the Klikov Formation in the central part of the Třeboň Basin in southern Bohemia provided ~ 70 m thick alluvial succession composed of alternating sandstone and mudstone intervals that overlays deeply weathered crystalline basement. The mudstone interval in the lower part of the Klikov Formation is separated by sandy layers into several 2–4 m thick fining-upward units. The sharp-based sandy layers with fusain, carbonized stems and rip-up clasts of underlying mudstone are interpreted as avulsion deposits. They grade upwards into heterolithic sand-silt sequence and mottled massive mudstone with burrows, rhizohalos and variably developed pedogenic features. Such cyclic arrangement probably reflects autogenic processes on distal floodplain with episodic deposition and upward increasing subaerial exposition and pedogenic overprint. In the middle to upper parts of the Klikov Formation up to 6 m thick channel sandbodies with sharp erosional bases cutting into the underlying laminated sand-silt heteroliths of channel levee deposits occur. The thickness of the single-storey sandbodies corresponds usually to c. 2 m which suggests up to 3 m deep channels during bankfull discharge. The thicker multi-storey sandbodies record channel amalgamation on the alluvial ridge or shallow paleovalley fillings. The sandbodies grade upwards to massive mudstones of abandoned channel fills and floodplain deposits. These floodplain units are up to 8 m thick and consist of variegated massive mudstones interrupted by discrete up to 1 m thick fining upward layers of rippled sandstone representing crevasse splay deposits. Depositional context including preserved levee deposits, abandoned channel fillings and floodplain finegrained deposits suggests rather higher sinuosity of the formative rivers. Palaeosol profiles represent pedogenically modified floodplain fines with gradational bases and sharp erosive top surfaces. At least 10 palaeosols were identified in the measured section, forming mostly discrete profiles up to 2 m thick consisting of several B-horizons that differ in the degree of the soil structure development, colour, mottling, grain size, presence of clay hypocoatings and bioturbation index. The most common Bw horizons form lower parts of the profiles and have no or only a weakly developed angular blocky structure (ABS). The typical mottling is caused by a hierarchical system of vermicular greenish-grey reduction rhizohalos, that may be filled by silt to sand or illuviated clay hypocoatings and probably follow the original plant root system. Some patches have diffuse orange rims of iron oxides, probably represented by goethite. Mudstone of Bsst horizons displays well-developed ABS with rare wedge-shaped peds and contains a number of illuviated clay skins and redox depletions. Vertic features like fine cracks filled by sand are common, and slickensides with clay hypocoatings occur rarely. Mudston","PeriodicalId":37965,"journal":{"name":"Geoscience Research Reports","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44359019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Natural radioactivity of sedimentary rocks in the northeastern part of the Moravo-Silesian Palaeozoic Basin","authors":"J. Zimák","doi":"10.3140/zpravy.geol.2022.15","DOIUrl":"https://doi.org/10.3140/zpravy.geol.2022.15","url":null,"abstract":"The paper provides detailed information on the natural radioactivity of sedimentary rocks in the northeastern part of the Moravo-Silesian Palaeozoic Basin in the Bohemian Massif. The studied area is dominated by the Lower Carboniferous flysch sediments belonging to the Horní Benešov, Moravice, and Hradec-Kyjovice formations (from botttom to the top). These three flysch formations consist of siliciclastic sediments, mainly graywackes, siltstones, silty shales, and clay shales, while conglomerates are less abundant. The overlying sediments of the Ostrava Formation (Namurian) occur on the eastern margin of the studied area. The Ostrava Formation has a character of a paralic coal-bearing molasse with alternating beds of sandstone (or arkose), siltstone and claystone. The sediments often have an elevated content of organic matter, concentrating into coal seams. The rocks of the Ponikev Formation (Devonian) occur in a narrow belt in the western part of the studied area. The Ponikev Formation consists mainly of silicites. Potassium, uranium and thorium contents were measured using a laboratory gamma-ray spectrometer in 1612 rock samples from 672 localities on five map sheets (1 : 50 000 scale). The calculated values of mass activity of 226Ra equivalent (am) demonstrate that the natural radioactivity of sedimentary rocks of all three flysch formations is lower or similar to that of the average Earth crust (about 180 Bq . kg–1). The radioactivity of flysch sediments increases with decreasing grain size from psephites (average am is 122 Bq . kg–1) to psammites (144 Bq . kg–1) and to aleurites + pelites (188 Bq . kg–1). Siltstones and claystones with a low organic matter content (226 Bq . kg–1), coaly siltstones and coaly claystones (240 Bq . kg–1), coaly sandstones and arkose sandstones (232 Bq . kg–1), and coal (202 Bq . kg–1) of the Ostrava Formation show slightly higher average am values. The relatively high radioactivity of these sediments is related to the elevated content of uranium (7.9 ppm on average).","PeriodicalId":37965,"journal":{"name":"Geoscience Research Reports","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47851340","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Report on the occurrence of the acidulous waters below the final slope of the ČSA open-pit (Most Basin)","authors":"V. Goliáš, P. Urban, Martin Přibil, P. Škácha","doi":"10.3140/zpravy.geol.2022.05","DOIUrl":"https://doi.org/10.3140/zpravy.geol.2022.05","url":null,"abstract":"Three springs of acidulous water were found in the area of the deep lignite mining, which began in 2014 in the ČSA open-pit (Albrechtice near Most cadastre). One spring (JZ 163) flowed directly from the casing of the exploratory well, cut slightly above the adit floor. Two other sources (CH1 and CH2) were springs directly in the coal seam. The springs represent Na-HCO3 (JZ 163), Na-HCO33-SO4 (CH1) and Na-Ca-SO4-HCO3 (CH2) hydrochemical type of waters. Their total mineralization varied between 2.3 to 2.8 g/L and the temperature was of up to 29.1 °C. In all cases, the springs were accompanied by massive CO2 outflows. The described occurrence belongs to the northern belt of the acidulous waters underneath the Krušné hory Mts. (Erzgebirge Mts.), linking the important localities of carbonated waters in Klášterec nad Ohří and Bílina located along the Eger Rift. The mine was closed on 27 April 2020 and the site is no longer accessible.","PeriodicalId":37965,"journal":{"name":"Geoscience Research Reports","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42961741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Diversity of quartz and muscovite chemistry within the orthogneiss-granite-pegmatite-quartz vein complex at Přibyslavice, NE Moldanubicum, Czech Republic: markers of their relation in origin","authors":"K. Breiter, J. Ďurišová, Zuzana Korbelová, M. Vašinová Galiová, Michaela Hložková","doi":"10.3140/zpravy.geol.2022.07","DOIUrl":"https://doi.org/10.3140/zpravy.geol.2022.07","url":null,"abstract":"The complex of leucocratic granitoid rocks at Přibyslavice (Fig. 1), composed of muscovite-tourmaline orthogneiss, muscovite granite and several types of pegmatites, is well known for numerous finds of interesting minerals like large almandine crystals (Breiter et al. 2005b), Li-Fe-Mn phosphates (Povondra et al. 1987), nigerite (Čech et al. 1978), columbite and cassiterite (Šrein et al. 2004, Breiter et al. 2006), lepidolite (Šrein et al. 2004) and oxy-schorl (Bačík et al. 2013). Less attention has been paid so far to the petrology of orthogneisses, granite and pegmatites and their genetic relationships. This study aims, based on the chemical composition of quartz and muscovite, to assess possible genetic links among all these rocks of granitoid composition including an associated cassiterite-bearing quartz vein with a B, Ta-rich metasomatic halo. Major elements in micas were analyzed using electron microprobe, and trace elements in both quartz and mica were determined using laser ablation-ICP-MS according to methods described in Breiter et al. (2017, 2020). About 550 spot analyses of quartz and 220 spot analyses of mica allow reliable definition of the typical composition of quartz and mica from all types of studied rocks (Tables 2, 3). Some genetic relationships are visualized in Figs. 2 and 3. The Přibyslavice orthogneiss is geochemically more evolved than petrographically similar orthogneisses through entire Moldanubicum as expressed not only in bulk rock chemical composition but also in trace element composition of quartz (higher Al, Ge and Li contents, Fig. 2) and muscovite (higher Li, Nb, Ta, Sn and W contents, Fig. 3). Pegmatoids at Přibyslavice and nearby Březí, forming small nests in orthogneisses with a gradual mutual transition, are interpreted as in situ anatexites. The direct genetic link between the granite intrusion and the quartz vein with cassiterite and B, Ta-rich metasomatites (tourmaline + Ta-rutile) is supported by the Sn, Nb and Ta enrichment of granite. It is highlighted by the relative distribution of Nb and Ta, with Nb preferentially bonded to muscovite in granite and Ta segregated into a fluid (see e.g. Stepanov et al. 2014). Chemical and mineral similarity between the granites and the orthogneiss suggests a common source lithology located deep below the present surface. During the first melting of the protolith in the late Cambrian (Vrána – Kröner 1995), a boron-rich melt was formed, which extracted most boron from the source and facilitated the origin of tourmaline orthogneiss. The second, Variscan melting of the same or a very similar protolith produced a melt slightly enriched in F and Li. We assume that the Přibyslavice granite represents only a small proportion of this melt, strongly enriched in Sn, W, Nb and Ta due to fractionation. Chemistry and mineralogy of several types of associated pegmatites suggest their relation rather to the granite melt than to the anatexis of the orthogneiss. The difference in their c","PeriodicalId":37965,"journal":{"name":"Geoscience Research Reports","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46376572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Risk element assessment in sediments of the Olše River and its significant tributaries","authors":"Michaela Buršíková, E. Geršlová, M. Geršl","doi":"10.3140/zpravy.geol.2022.08","DOIUrl":"https://doi.org/10.3140/zpravy.geol.2022.08","url":null,"abstract":"The main objective of research was to assess the current level of bottom sediment and water pollution of the Olše River and its tributaries. The Olše River is an important stream in the Upper Silesian Basin which was significantly affected by coal mining and industrial activities in the past (Martinec et al. 2006). Monitoring of the area by the Povodí Odry State Enterprise (the Odra River management) has shown that the water quality in the river has significantly improved due to the development of municipal wastewater treatment plants. Currently, saline waters from coal mines in the Karviná sub-basin are considered to be the biggest threat to the river environment. A total of 19 river sediment and 9 surface water samples were collected (Fig. 1). The elemental content was determined using X-ray florescence spectroscopy (XRF); for selected river sediments, the organic carbon content was determined using the Elementar Vario TOC CUBE device. The loading of river sediments by elements was evaluated using Igeo Class. The content of major ions (HCO3–, K+, Ca2+, Na+, Mg2+, SO42– and Cl–) in the surface water samples was determined in the laboratory. The water in the Olše River belongs to the hydrochemical type of Ca-HCO3. The water in the Karvina Creek near the mining works is highly mineralised and represents a single case of the Na-Cl hydrochemical type. Despite the significant mineralisation level, the water from this creek does not significantly affect the quality of the water in the Olše River. The highest enrichment of river sediments compared to the natural background was found for Zn (Table 1) at all sites. Zinc is one of the elements with rather high mobility and tends to be bound to hydrated Fe and Mn oxides that occur in rather large quantities on adjacent spoil heaps in the area and can thus enter the system very quickly. The Mn (340 to 2,553 mg/kg) as well as Sr (71 to 1,836 mg/kg) concentrations are elevated compared to those in global shales (850 mg/kg and 300 mg/kg, respectively; Turekian – Wedepohl 1961). Their contents in the Upper Silesian Coal Basin river sediments should be systematically monitored. The Olše River sediments were slightly to moderately contaminated with Cr and Pb (Table 1). This is not considered to be related to mining but rather to road runoffs and the fact that the river flows through industrial areas.","PeriodicalId":37965,"journal":{"name":"Geoscience Research Reports","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41512892","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Radioactive springs in Prague-Čimice","authors":"Antonín Lustik, V. Goliáš, Petr Cupal, J. Bruthans, Jan Schröfel, V. Kachlík, Lenka Jílková, M. Mihaljevič","doi":"10.3140/zpravy.geol.2022.04","DOIUrl":"https://doi.org/10.3140/zpravy.geol.2022.04","url":null,"abstract":"Groundwater inflows showing notable natural radioactivity have been found at the northern end of the Holešovice cable tunnel close to the Čimice Grove. This groundwater originates from the Barrandian Neoproterozoic slates of the Blovice accretionary complex, Belt I (Šárka-Zbiroh Belt) at depths approximately 100 meters below the surface, occurring along 50 meter profile of the cable tunnel. Water springs are dispersed in the spring area, with the total discharge of 2 L/s. Groundwater is cold (T ~ 11.1 – 12.3 °C), neutral (pH ~ 6 – 7.48), suboxic to oxic (Eh (ORPH) ~ 177 up to 418 mV), of a hydrochemical type Ca-Mg-HCO3, total mineralization being around 702 mg/L. Radon activity (222Rn) varies between 415 and 1195 Bq/L and radium activity (226Ra) ranges between 0.18 and 5.3 Bq/L. Activities of Rn and Ra are relatively high. Currently, this is the most radioactive water within Prague agglomeration. This water is relatively aggressive as well, causing damage to the concrete lining of the cable tunnel and also allowing formation of calcite precipitates with an increased radium (226Ra) activity.","PeriodicalId":37965,"journal":{"name":"Geoscience Research Reports","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69718703","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"New occurrence of rocky-coast facies near Ronov nad Doubravou (Kolín lithofacial development, Bohemian Cretaceous Basin)","authors":"Pavel Čáp, R. Vodrážka, L. Švábenická, M. Chroustová","doi":"10.3140/zpravy.geol.2022.02","DOIUrl":"https://doi.org/10.3140/zpravy.geol.2022.02","url":null,"abstract":"A rocky-coast facies in the Bohemian Cretaceous Basin (BCB) are developed mainly in the Kolín lithofacial area at its southern margin. Ronov – the newly described locality – is situated south of Ronov nad Doubravou, on the right bank of the Doubrava river near the St. Kříž church. The outcrop located in a ditch was partially excavated in order to study the character and extent of Cretaceous sediments (Beds No. 1–3; see Figs. 1–3). Bed 1 is composed of red clay with yellow streaks, representing lateritically weathered crystalline bedrock – likely amphibolites and garnet migmatites (Fig. 2). Overlying bed 2 consists of yellow to gray-green clay; in the lower part, the layer contains fragments of fossils that occur in the overlying layer, and sandy “intraclasts” interpreted as bioturbations. The most conspicuous bed 3 (25 cm in thickness) is represented by calcareous, coarse-grained sandstone to conglomerate with glauconite and abundant fauna (mainly fragmentary; Figs. 4 and 5). This type of rock in the wider area (between Ronov nad Doubravou and Žleby) was reported by Sejček (1982) who described three occurrences as scree or fragments on the surface but has not found any rock outcrops in situ despite excavation work. The individual layers were sampled for the study of foraminifers, calcareous nannoplankton and macrofauna. Shells of Rhynchostreon suborbiculatum, which are always disarticulated, often fragmented and bioturbated (Entobia exogyrarum), represent the most prominent element of macrofauna. In addition, Rastellum diluvianum and Amphidonte halitoidea, unspecified large colonies of bryozoans, spines of the echinoids Cidaris vesiculosa, complete shells of brachiopods Cyclothyris aff. difformis and tiny teeth of sharks Otodus rarely occur. Calcareous nannofossils were found only in bed 3. Isolated small, mostly difficult to identify fragments belong to long-range stratigraphic taxa (Fig. 6) and may indicate an interval from the uppermost Cenomanian to the lowermost Turonian. Similar poor nannofossil assemblages are known also in other rocky-coast facies of the BCB. The refining indicator of stratigraphic classification is thus macrofauna. Similar communities with Rhynchostreon suborbiculatum and echinoderms are known from Upper Cenomanian and Lower Turonian in the area of Heřmanův Městec, Čáslav and especially Kutná Hora. However, brachiopods Cyclothyris aff. difformis and oyster Amphidonte halitoidea recorded from Ronov are typical representatives of Upper Cenomanian “rocky-coast” faunas, whereas typically Lower Turonian elements such as the oyster Exogyra reticulata, Exogyra sigmoidea, or the spines of the Cidaris sorigneti are missing in the studied community. The study of macrofossil and nannofossil communities shows that the Upper Cretaceous rocks, represented by the calcareous glauconitic sandstones to conglomerates in Ronov locality, are most likely of the Upper Cenomanian age and represent the Korycany Member of the Peruc-Korycany Forma","PeriodicalId":37965,"journal":{"name":"Geoscience Research Reports","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47202062","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dendritic borings in brachiopods shells from the Middle Devonian (Eifelian) of the Prague Basin (Barrandian area, Czech Republic)","authors":"M. Mergl, Nikola Šmídtová","doi":"10.3140/zpravy.geol.2022.03","DOIUrl":"https://doi.org/10.3140/zpravy.geol.2022.03","url":null,"abstract":"Three ichnospecies of dendritic borings (Clionolithes cf. cervicornis, C. isp. A, and C. isp. B) were observed in abundant brachiopod shells in the Třebotov Formation (lowermost Eifelian, zone Polygnathus partitus) in two Prague localities (Praha-Holyně, “V rokli”, and Praha-Barrandov, street “K Barrandovu”). Borings are generally small-sized, of about 1 mm, but they can reach up to 4 mm. Borings are preserved inside thick translucent walls of brachiopods smooth shells (Trigonatrypa holynensis, Xenomartinia monoseptoides and Clorinda sp.). Borings are very frequent (almost in all examined shells), but never pass through a whole wall thickness of a brachiopod. Two or even more borings, commonly of a different type, are preserved on an individual shell. Both valves of articulated specimen may be bored, while the shell interior is devoid of borings neither shows any response to the boring activity such as uneven internal biomineralization. Majority of tunnels bores inside the shell wall, and the borings are opened by small irregular central pit. As more than a half of examined shells were infected, bioerosion likely had a negative impact on the shell preservation. Our study shows that the brachiopod infestation was selective. Only thick calcitic shells were bored, while thinner shells or exopunctate brachiopods (Holynatrypa, Peridalejina, Prokopia) were not a target of the borers. Similarly, crinoid and other echinoderm ossicles do not show any signs of a boring. A different dendritic boring referred to as Clionolithes radicans was observed on a shell of brachiopod coming from the Acanthopyge Limestone (Choteč Formation, Eifelian) from Zadní Kobyla locality near Koněprusy. The stellate trace is substantially larger (4.3 mm × 2.8 mm) than borings from the Třebotov Limestone, with deep and externally open canals. Borings from the Třebotov Limestone come from so-called “white beds”. These soft beds originated by weathering of a hard limestone, leaving loose generally small bioskeletal remains of echinoderms, gastropods, brachiopods, ostracods, dacryoconarids and other invertebrate groups. Dacryoconarid shells and crinoid ossicles dominate. The life assemblage occupied a deeper weakly hypoxic perireef environment below the fotic zone. The dendritic boring from the Acanthopyge Limestone comes from a completely different environment. Associated diverse and generally large brachiopods, fragmented fenestrate bryozoans and abraded tabulate and rugose corals (including Calceola sandalina) indicate a shallow-water highenergy reef environment. This is the first report of dendritic borings from the Eifelian of the Prague Basin. It confirms not only so far unknown presence of their borers in the area, but also reveals that their activity can be observed in the weakly lithified Devonian limestones in the area.","PeriodicalId":37965,"journal":{"name":"Geoscience Research Reports","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47227695","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Lithium-bearing phosphates and micas in Homolka leucogranite","authors":"R. Nahodilová","doi":"10.3140/zpravy.geol.2022.06","DOIUrl":"https://doi.org/10.3140/zpravy.geol.2022.06","url":null,"abstract":"Homolka granite forms intrusion of highly fractionated leucocratic magma which belongs to the youngest members of the Moldanubian Pluton. The age of the intrusion was estimated between 319 and 315 Ma. The Homolka granite is P-rich, peraluminous and strongly enriched in Li, Rb, Cs, Sn, Nb, Ta and F, showing high U (8–20 ppm) and low Th (< 3 ppm) contents. This study focuses on Li-bearing minerals – phosphates and white micas. Their modal proportions correspond to 1–3 vol. % and 5–15 vol. %, respectively. Both mineral groups occur in several generations in the rock. The first phosphate generation (for example, Al-bearing montebrasite or Fe-Mn-bearing triphylite) contains up to 11 wt. % Li2O. The first generation of mica (Li-phengite) contains about 7–8 wt. % F and up to 1 wt. % Rb2O with Li2O content ranging between 1.3 and 1.9 wt. %. The second generation of white mica, replacing Li-phengite, is depleted in F and Rb and shows decrease in Li2O to 0.5–0.9 wt. %. Despite the low total content of lithium (Li2O = about 0.1 wt. %) in the rock, the occurrence of the leucocratic Homolka granite is not negligible. Because of the high economic potential of lithium, these highly evolved peraluminous and lithium-bearing intrusions will deserve a special attention in the future.","PeriodicalId":37965,"journal":{"name":"Geoscience Research Reports","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43535436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mobility of elements bound in river sediments affected by coal mining","authors":"Marcela Cahová, E. Geršlová, J. Kuta","doi":"10.3140/zpravy.geol.2021.10","DOIUrl":"https://doi.org/10.3140/zpravy.geol.2021.10","url":null,"abstract":"Trace elements are a natural part of the environment; however, anthropogenic activities can significantly contribute to their abundance and mobility in the environment. This study is focused on trace element mobility in sediments of a river system (the Bílina River, Czech Republic) affected by coal mining. It follows the previous research of trace element mobility in lignite from the Main Coal Seam in Bílina Quarry (Cahová et al. 2019). Eight samples of river sediment were taken along the Bílina River flow to evaluate the changes in As, Cr, Ni and V contents. Sequential extraction analysis modified according to Querol et al. (1996) and Feng et al. (2000) was used to determine the mobility of the studied elements under conditions close to natural. The amount of studied elements contained in each extract was determined by inductively coupled plasma mass spectrometry (ICP-MS). Water-extractable species of toxic elements may pose a risk to the environment due to their high mobility and bioavailability. It has been found that the release of compounds from the river sediment into the environment is conditioned by acidic conditions. While total metal contents in the river sediment ranges from tens to hundreds of μg/g, the amounts of metals extracted in each extraction step (deionised water and 1 M ammonium acetate at pH 5 and 7), typically reaches only tens to hundreds of ng/g, therefore the amount of easily mobilized elements is minimal. Mobilita prvků vázaných v říčních sedimentech ovlivněných těžbou uhlí","PeriodicalId":37965,"journal":{"name":"Geoscience Research Reports","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44937574","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}