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Od grebena do bazena – progradacija plitkovodnih karbonata preko srednjetrijaskog riftnog bazena sjeverozapadne Hrvatske (Ivanščica, SZ Hrvatska)
No full textThe NW part of Croatia represents a tectonically complex area at the junction of the Dinarides and the Southern Alps. In Očura Quarry on Ivanščica Mt. there is 34 m thick section composed of volcanic, volcaniclastic and carbonate rocks that can be divided into three parts. The lower interval (7 m) is composed of dominantly basaltic rocks (SiO2 = 43–51 wt%). In the basal part glomeroporpyric basalt is followed by basaltic autoclastic breccia. The second interval (7–19 m) is composed of cm–dm irregularly and wavy bedded calcarenites, occasionally coarsening upward, with lithoclasts varying in size from fine sand up to fine breccia. Carbonate lithoclasts are mostly micritic limestones – biomicrite, pelmicrite, pelsparite, intrasparite, also bioclasts of bivalves, crinoids, ammonoids, brachiopods, and gastropods. Two types of basaltic lithoclasts are present in the dominantly calcarenite interval, one with the porphyric to glomeroporphyric texture, similar to the basalts of the lower part; and the other type completely hyaline. Lithoclasts are cemented by sparry calcite. In the coarser varieties lithoclasts are the same, with the only difference in the matrix found between the clasts, that is composed of fine calcarenites with basaltic lithoclasts. Calcarenites are interlayered by thin layers of biomicrites with filaments and radiolarians, and thin layers of fine to coarse ash vitriclastic tuffs. In the middle of this interval around 1.5 m thick matrix supported breccia occurs with limestone and basaltic lithoclasts. Third interval of the section (19–34 m) is composed of extremely unsorted breccia with slump texture. Clasts of limestones, calcarenites, and subordinary basalts are supported by fine grained matrix of carbonate and basaltic particles. Abundant framestone clasts are present in the breccia, containing complex reef community, dominating of sponge Celyphia zoldana, with other microorganisms of uncertain taxonomy Plexoramea cerebriformis and Olangocoelia otti, and others. Generally in this interval carbonate material is predominant over basaltic lithoclasts. The investigated section represents sedimentation in the deeper marine environment near the steep edge of the carbonate platform and reef. Basalts found at the base of the section present effusions in the marine areas, and their fragmentation and reworking. A thick interval of calcarenites with basaltic lithoclasts is formed by shedding of the carbonate material from the nearby platform to the pelagic/basinal areas, indicated by the pelagic limestone interlayers. Chaotic breccia with meter sized fragments of reefal limestones indicates a more proximal position to the shallow marine area from which these clasts were derived. Slump texture emphasizes gravitational processes. The general trend of coarsening upward, as well as the predominance of the framestone clasts in the breccias imply the progradation of the platform over the basinal areas. Therefore, indicating a relatively rapid closure of the basinal/pelagic areas and cessation of the extensional tectonics related to the Neotethyan rifting. One sample (OD-15A) bears conodonts Gladigondolella tethydis (Huckriede), Paragondolella trammeri (Kozur), that indicate Illyrian to Lower Longobardian age of this section. That age is in the accordance with the regional cessation of the volcanic activity in the Ladinian, and progradation of the platforms over the basinal areas that were filled with various clastic, volcaniclastic, silicious and pelagic sediments
Genesis and epigenetic evolution of the Minjera bauxites, Croatia, Istria
No full textPyritisation of bauxites occurs as a result of their epigenetic reduction during the formation of swampy environments in the bauxite cover during the initial phase of the transgression, which commonly follows the formation of the bauxite. The Minjera bauxites, which formed during the terrestrial phase which lasted between the Late Cenomanian/ Late Santonian and Early Eocene, were pyritised. The epigenetic pyritisation of these bauxites was related to the transgression that followed their formation, which led to the formation of ponds and swamps in the paleo-depressions in the karstified terrain, such as the sinkholes and canyons filled with the bauxite. Therefore, all of the Minjera bauxite bodies are covered by Lower Eocene Liburnian beds formed in such environments. The Minjera bauxites have been mined in the past, but only the pyrite-containing bauxite was used in the production of alum and vitriol, while the red bauxite was left in the tailing heaps in the area. Pyritised bauxite samples from two Minjera bauxite bodies (D-1 and D-15) were collected, with the aim to reconstruct their genesis and the processes which led to their formation and subsequent pyritisation. Two main types of bauxites, the grey bauxite and the pyritised bauxite, were distinguished based on their mineralogy, geochemistry as well as their structure and texture. The grey bauxite contains high amounts of kaolinite and moderate to high amounts of diaspore, while containing no or little böehmite. Iron sulphides, represented mainly by pyrite and sporadically by marcasite, are generally present in very low amounts in this type of bauxite and appear as veinlets and crystal clusters in the matrix and bauxite clasts and as replacements of iron oxide rich laminae in ooids. This type of bauxite is also enriched in bases and large ion lithophile elements compared to pyritised bauxite, which is likely related to lower leaching intensity. Pyritised bauxite contains high amounts of böehmite and iron sulphides, while containing very little to moderate amounts of kaolinite, and almost no diaspore. Iron sulphides appear in these samples in many different morphologies and textures. They replace the iron oxide-rich laminae within the ooids and the fine-grained matrix between the bauxite clasts and ooids. In samples where the matrix was not completely pyritised, the pyritisation started from many crystallisation centres, from which iron sulphides grew outward, either in the forms of framboids or rosettes composed of needle shaped crystals. Iron sulphides in these samples commonly crystallize along the fractures, which is also seen on a large scale, in the form of centimetre-thick veins of iron sulphides parallel with the boundary between the bedrock and the bauxite. Both bauxites are enriched in heavy REEs, and display a slight negative cerium anomaly, which indicates the influence of marine porewater. Different textures and morphologies of iron sulphides suggest variations in the saturation with iron and sulphur and are probably linked with the sea-level variations during the initial stages of the transgression, which could have affected the production of organic matter in swampy environments that developed in the cover of the bauxite during this stage. The ingression of marine porewater was most likely the source of sulphur, which was derived from the microbial reduction of sulphur in the organic matter-rich environment. The pyritisation appears to have affected each bauxite deposit differently, since the grey bauxite is almost exclusively found in the D-15 deposit, while the pyritised bauxite is found only in the D-1 deposit. Besides their distinct epigenetic evolution, this also suggests that bauxites of different grades formed contemporaneously in the area, as the D-15 body is composed mainly from highly kaolinitic grey bauxite and the D-1 body from the highly böehmitic pyritised bauxite. This is probably related to different morphologies of the two bauxite bodies, as the D-1 body is much larger and steeper (> 20 m) than the D-15 bauxite body (< 5 m). The differences in their morphologies likely developed as a consequence of their different palaeotopographical positions, which led to different rates of chemical weathering between the two bauxite bodies
Koraci prema uspješnoj popularizaciji STEM-a kod djece i mladih : vodič za organizacije civilnog društva
No full textMineraloška i geokemijska svojstva baritno-fluoritne mineralizacije Meovršje, Srednje bosanske škriljave planine, Bosna i Hercegovina : završni rad
No full textTerenskim istraživanjima na području gorja Meovršje, u blizini Kreševa u Srednjebosanskom škriljavom gorju zabilježene su pojave barita i fluorita. Napravljene su mineraloške i geokemijske analize kako bi se definirali stijena domaćin, tipovi i odnos mineralizacije i stijene domaćina, te njihov kemijski sastav. Makroskopskim i mikroskopskim analizama utvrđeno je da je dolomit stijena domaćin, različitog stupnja svježine. Baritno-fluoritna mineralizacija nalazi se unutar dolomita u obliku žilica i pukotina ispunjenih baritom, kvarcom, fluoritom i tetraedritom, podređeno malahitom i azuritom. Mikroskopskom analizom mineralizacije utvrđeno je da se barit nalazi uz rubove žila, te da ima dobro razvijene, izdužene forme. Kvarc se uglavnom nalazi unutar pukotina ili na kontaktu između stijene domaćina i barita. S obzirom na undulozno potamnjenje pretpostavlja se da je prošao period povišenih tlakova, potencijalno kao posljedica metamorfoze. S druge strane, fluorit je češće hipidiomorfnih formi, te je mikroskopskom analizom utvrđeno da većinom popunjava međuporni prostor između barita i stijene domaćina. Geokemijske analize, s vrlo visokim udjelima CaO (max. 50,06 mas. %) i MgO (max. 33,99 mas. %) potvrdile su dolomit kao stijenu domaćina. U mineraliziranom dijelu stijene, geokemijske analize su uz pojave BaO, SO3 i povišeni Sr koji upućuje na izmorfne zamjene Sr-Ba u baritima zabilježile i povišenje Cu, Zn, Ag, Hg i Sb, s time da udio antimona u zoni mineralizacije varira između 0,04 i 3,63 mas. %, što upućuje na pojavu antimonitno-srebrnonosne tetraedritne mineralizacije. S obzirom na navedeno, može se zaključiti da na lokalitetu Meovršje postoji potencijal za daljnja istraživanja u svrhu pronalaska baritnog i fluoritnog orudnjenja, ali vezano uz njih i potencijalnu pojavu antimonsko-srebrnonosne mineralizacije i mineralizacije zlata
Seismic geomorphology of Pannonian clastic reservoirs in Drava and Zala Basins, Pannonian Basin System
No full textMature basins provide a wealth of data for the reconstruction and mapping of their sedimentary evolution and architecture as well as regional paleo-geographic changes. In turn, these often lead to a better understanding of geological processes and thus provide a basis for novel concepts in exploration of subsurface. The Neogene Pannonian Basin System (PBS) nested between the Dinarides, Alps and the Carpathian arc in Central Europe is such a mature area with more than a century hydrocarbon exploration and production history. The upper Miocene to Pliocene sediments, referred to as Pannonian Stage, were initially deposited in an under-filled lake basin displaying gradual transgression followed by a powerful regression characterized by prograding and aggrading clinoforms on reflection seismic data. Relative chronostratigraphic framework was defined by clinoform sets mapped along with their rollover points across Drava and Zala basins. Based on seismic attributes, log patterns and available core data, clastic depositional features and architectures were delineated across different depositional environments within lake basin clinoforms. Each depositional feature is described upon its position within clinoforms, type of clinoform trajectory and typical log pattern. Finally, depositional features are described in their typical sizes (based on 3D seismic data) and reservoir quality. Integrating various data resulted in more complete temporal and spatial development of depositional environments during clinoform deposition as well as depositional features. Mapping of the depositional features across clinoforms resulted in considerable range of reservoir sandbody types that can be recognized on 3D seismic within Pannonian Basin System
Assessment of soil erosion in the Banovina area using the ArcSWAT method : master's thesis
No full textU ovom istraživanju analizirana je erozija tla na području Banovine koristeći ArcSWAT metodu. Erozija tla i njen negativan utjecaj na održivost poljoprivrede i okoliš su posebno važni nakon nedavnog potresa na Banovini. Korištenjem ArcSWAT modela, baziranog na GIS tehnologiji, proučavani su hidrološki procesi, vodni tokovi, erozija tla i kvaliteta vode. Vizualno privlačni dijagrami i karte pružaju detaljan uvid u različite aspekte erozije tla na tom području, uključujući raspon vrijednosti prosječnog prinosa sedimenata koji ukazuju na različite razine gubitka tla i taloženja sedimenata. Rezultati su identificirali područja s vrlo visokom stopom erozije, naglašavajući potrebu za provedbom mjera očuvanja tla kako bi se smanjili negativni utjecaji erozije. Ova studija pruža važne informacije za razumijevanje erozije tla na području Banovine nakon potresa te može poslužiti kao temelj za daljnje mjere zaštite tla i održivog upravljanja.In this research, soil erosion in the area of Banovina was analyzed using the ArcSWAT method. Soil erosion and its negative impact on the sustainability of agriculture and the environment are particularly important after the recent earthquake in Banovina. Using the ArcSWAT model, based on GIS technology, hydrological processes, water flows, soil erosion and water quality were studied. Visually appealing diagrams and maps provide detailed insight into various aspects of soil erosion in the area, including a range of average sediment yield values that indicate different levels of soil loss and sediment deposition. The results identified areas with a very high rate of erosion, highlighting the need to implement soil conservation measures to reduce the negative impacts of erosion. This study provides important information for understanding soil erosion in the Banovina area after the earthquake and can serve as a basis for further soil protection measures and sustainable management
Cycling map with geological phenomena of the town of Ogulin and its surroundings in the QGIS program : master's thesis
No full textUpotreba QGIS sustava u izradi konceptualne karte s geomorfološkim, hidrogeološkim i speleološkim lokacijama grada Ogulina i okolice. Prikaz područja grada Ogulina i okolice u sklopu geologije te svih geoloških pojava koje će pratiti biciklističke staze s opisima lokacija te pobliže upoznavanje geologije grada Ogulina i okolice. U diplomskom radu je opisana izrada karte te detaljnije pojašnjene lokacija.The use of the QGIS system in the creation of a conceptual map with geomorphological, hydrogeological and speleological locations of the town Ogulin and its surroundings. Presentation of the area of the town Ogulin and its surroundings as part of geology and all geological phenomena that will follow the bicycle paths with descriptions of locations and a closer introduction to the geology of the town of Ogulin and its surroundings.The diploma thesis describes the creation of the map and explains the location in more detail
Production of biogas from municipal waste : master's thesis
No full textBioplin se iz komunalnog otpada može proizvoditi na više načina, a najčešći su proizvodnja bioplina s odlagališta komunalnog otpada te proizvodnja bioplina u anaerobnom digestoru pri čemu se kao nusprodukt dobiva digestat. Za učinkovitu proizvodnju bioplina na odlagalištima komunalnog otpada potrebna je odgovarajuća infrastruktura u obliku plinskih bušotina, horizontalnih i vertikalnih cijevi te sustava procjedne vode. Za proizvodnju bioplina u anaerobnim digestorima potrebna je hermetički zatvorena komora te anaerobni uvjeti kao i prisutnost metanogenih bakterija. Neobrađeni bioplin se koristi u pogonima za proizvodnju električne energije. Za primjenu bioplina u vozilima ili za priključak na plinsku mrežu, potrebno je obraditi bioplin u biometan. Biometan u svom sastavu ima značajnu količinu metana uz minimalnu količinu ostalih plinova.Biogas can be produced from municipal waste in several ways, the most common of which are the production of biogas from a municipal waste landfill and the production of biogas in an anaerobic digester, where digestate is obtained as a byproduct. For the efficient production of biogas at municipal waste disposal sites, appropriate infrastructure is needed in the form of gas wells, horizontal and vertical pipes and leachate systems. The production of biogas in anaerobic digesters requires a hermetically sealed chamber and anaerobic conditions, as well as the presence of methanogenic bacteria. Unprocessed biogas is used in plants for the production of electricity. To use biogas in vehicles or for connection to the gas network, it is necessary to process biogas into biomethane. Biomethane has a significant amount of methane in its composition with a minimal amount of other gases
Paleoenvironmental and paleoclimatic changes during the deposition of Upper Jurassic bauxites and their immediate cover: case study of the Rovinj bauxite pit, Istria, Croatia
No full textThe aim of this study was the reconstruction of paleoclimatic and paleoenvironmental changes which occurred during the deposition of Upper Jurassic bauxite, and their cover beds, which comprise a cyclic alternation of clays, limestones, and black pebble breccias. Clay and bulk mineralogy, geochemistry and micromorphology of bauxites and clays was studied using XRPD, SEM-EDS, ICP-MS, XRF, AAS and petrography. The bauxite is composed from haematite, boehmite and kaolinite with variable amounts of 14 Å clay, illite and titanium oxides. The composition of major oxides is consistent with the mineralogical composition and is uniform throughout the profile. The values of rare earth elements and variations in the trace element values displayed differences throughout the bauxite profile, distinguishing two bauxite sections, both capped by two clay illuviation rich horizons. The upper section has numerous erosional features and clastic bauxite beds, which when coupled with its different trace elemental fingerprint indicates its deposition over the older pelitomorphic section. This change is likely a consequence of a paleoclimatic shift towards a more seasonal climate during the formation of the younger part of the bauxite. This can be related to the oscillating transgression succeeding the bauxite formation, which is recorded in the cyclical beds covering the bauxite. The clays from the cover beds are composed from dioctahedral vermiculite, kaolinite, illite and a mixed-layer clay mineral (MLCM) consisting of illite and dioctahedral 14 Å phyllosilicate. The increase in illite and MLCM over kaolinite and the increase in Sr/Ba ratio along the profile, indicate a change from a lacustrine towards a marine environment. The iron speciation data supports this, as it recorded the redox changes which indicate a transition from a closed lacustrine environment to an open marine environment. Overall, the study of both bauxites and their cover, allowed a detailed reconstruction of a late Kimmeridgian transgression that followed a terrestrial phase in this part of the Adriatic carbonate platform. This work has been fully supported by Croatian Science Foundation under the project IP-2019-04-8054 – Wian- Lab (Western Istrian Anticline as an Ideal Natural Laboratory for the Study of the Regional Unconformities in Carbonate Rocks)
REE deposits in Adria region : karstic bauxites
No full textThe workshop "Rare Earth Elements value chain gaps and opportunities in the ADRIA region" is organized as part of the EIT project RECO2MAG - Novel grain boundaries engineered resource efficient Nd-Fe-B permanent magnets (financed by EIT KIC Raw Material)