<p> Proposed theories concerning the nature and mode of formation of limestone scallops are examined. Some progress is made toward a purely theoretical understanding. Scallop formation is simulated by generation on blocks of Plaster of Paris in a laboratory flume under known and controlled conditions and the relationships between the resulting features, the generating conditions and the base material examined. Field Evidence both confirms these relationships and reveals other unsuspected factors. The similarity between these features and others found on ablating snow surfaces is investigated and the same laws found to apply. </p> / Thesis / Doctor of Philosophy (PhD)

Canada is in the process of implementing a Deep Geologic Repository (DGR) to dispose of used nuclear waste. Adsorption behaviour of both Se(-II) and Tc(IV) onto granite, shale, limestone, illite, and MX-80 bentonite has been elucidated. Se(-II) adsorption onto granite and MX-80 bentonite displays a decrease in Rd with an increase in solution pH. Se(-II) adsorption onto granite decreases with an increase in solution ionic strength. Se(-II) adsorption onto MX-80 bentonite does not return evidence which supports an apparent effect due to the ionic strength. Tc(IV) adsorption onto shale, limestone, illite, and MX-80 bentonite remains constant as the solution pH increases. Ionic strength does not affect the magnitude of Tc(IV) adsorption across the adsorbents, however an increase in ionic strength accelerates Tc(IV) adsorption. Se(-II) surface complexation models are best simulated with the following surface complexes: ≡Feldspar_sSe-, ≡Biotite_sOH2HSe, ≡Albite_sSe-, ≡Montmorillonite_sSe-, and ≡Montmorillonite_sOH2HSe. Tc(IV) adsorption is best simulated with: ≡Biotite_sOTcO(OH), ≡Quartz_sOTcO(OH), (≡Feldspar_sOH)2TcO(OH)-, ≡Montmorillonite_sOTcO(OH), (≡Albite_sOH)2TcO(OH)-, ≡Illite_sOTcO(OH), and ≡Chlorite_sOTcO(OH). Se(-II) adsorption onto granite and MX-80 bentonite in CR-10 solution returns Rd values of (1.80 ± 0.10) m3∙kg-1 and (0.47 ± 0.38) m3∙kg-1, respectively. Tc(IV) adsorption onto granite and MX-80 bentonite in CR-10 solution returned Rd values of (1.47 ± 0.25) m3∙kg-1 and (2.19 ± 0.33) m3∙kg-1, respectively. Tc(IV) adsorption onto shale, limestone, illite, and MX-80 bentonite in SR-270-PW solution returned Rd values of (0.16 ± 0.10) m3∙kg-1, (0.44 ± 0.21) m3∙kg-1, (1.86 ± 0.44) m3∙kg-1, and (0.23 ± 0.10) m3∙kg-1, respectively. This thesis will further deepen the understanding of Se(-II) and Tc(IV) adsorption. / Thesis / Doctor of Philosophy (PhD) / Determining the adsorption of Se(-II) and Tc(IV) onto granite, shale, limestone, illite, and MX-80 bentonite is beneficial to choosing a location within Canada to locate a used nuclear fuel repository. This thesis aims to quantify the adsorption behaviour of Se(-II) and Tc(IV) in Ca-Na-Cl and Na-Ca-Cl solutions with respect to a varying solution ionic strength and pH. Quantification of the adsorption was accomplished with adsorption experiments used in conjunction with geochemical simulations. New simulated surfaces specific to granite, shale, and MX-80 bentonite have been developed to complete these simulations. A final achievement was quantifying the adsorption of Se(-II) and Tc(IV) in groundwater representative solutions specific to locations considered for the used nuclear fuel repository.

Located on the island of Gotland, Sweden, the File Hajdar limestone quarry is an important locality for domestic cement production. With depositional settings generally related to shallow sea carbonate ramps, the lithologies encountered on File Hajdar range from reef-associated limestone units to more basinal deposition of marls. As the depositional setting is related to the CaCO3-content (carbonate), which is an important property to consider during cement production, geological investigation of the area through conceptual 3D modelling could be a very powerful tool to enhance the general knowledge of the area or for planning future prospecting campaigns. Since the quality of the 3D model is related to the amount and quality of data utilized, data acquisition and management are very important steps in the construction of a 3D model. Two main campaigns with drill core extractions were done in 1993 and 1999, respectively. Along with resistivity data collected from skyTEM-measurements and ground surveys, subsurface geological information is quite extensive in the area. Using overall data and a reclassification of the lithologies, three main areas associated with reef complex deposition have been identified on File Hajdar. Corresponding to elevated resistivity measurements as well as classification in drill cores, two reef complexes centered around the quarry, have been described as the central- and southeastern reef complexes. Based on high resistivity anomalies in skyTEM-data along with field interpretations, the emplacement of a third reef complex is also interpreted in the northwestern parts of the study area (northwestern reef complex). However, as overall data is lacking at the location of the northwestern reef complex, further investigation is necessary before the relationship between the central- and northwestern reef complex can be fully investigated. Due to the generally indistinct transition between clay-rich limestone and marl, the subsurface boundary to the marl is rather insinuated. However, corresponding to low resistivity anomalies, outcroppings of the surfacing marl unit are outlined at the base of the File Hajdar rise. Future utilization of the produced 3D model could include the implementation of additional data or as a foundation during the planning of further prospecting campaigns in the area. Corresponding to the locations of the central- and northwestern reef complexes, these two areas are suggested to be most suitable for further investigation. / Som en viktig komponent i cementproduktion har Gotland sedimentära berggrund haft en historisk anknytning till kalstensutvinning. File hajdar brottet är beläget ca 5 km väst om tätorten Slite, på nordöstra Gotland, och står i dagsläget helt för den lokala kalkstensutvinningen av Cementa AB. Kalkstensenheterna på File hajdar kan generellt kopplas till revbildning under den geologiska silurperioden. Men baserat på den interna relationen till de innersta revkropparna kan även underklassificeringar av kalkstensenheterna konstrueras. Eftersom relationen till reven även är kopplat till kalkstenens karbonathalt (CaCO3), vilket är en väsentlig beståndsdel att beakta under cementproduktion, är det viktigt att urskilja mellan de olika kalkstensenheter som påträffas på File hajdar. En sådan urskillning kan visuellt uppnås om en konceptuell 3D-modell över geologin på File hajdar brottet och dess omnejd konstrueras. Med data från borrkärnor, framtagna under två prospekteringsprojekt, samt från mätningar av berggrundens elektriska egenskaper kan man indirekt tolka geologin i området. Då det mer massiva revkropparna förväntas ha sämre ledningsförmåga relativt de mer lerberikade märgel- och kalkstenarna, kan man anknyta områden med hög resistivitet (oförmåga att leda ström) till revstrukturer. Från mätningar tolkas området norr- och söder om täkten inkludera större revstrukturer. Även nordväst om täkten kan man antyda att en större revstruktur är lokaliserad. Men eftersom den nordvästliga strukturen sakna större utsträckning av data behöver denna studeras närmare. Då övergången mellan den underliggande märgelstenen och File hajdars ytliga kalkstenen sker gradvis blir gränsen mellan dessa två enheter svår att placera ut med någon större säkerhet. Detta medför att den underliggande märgelgränsen bör betraktas som en generaliserad övergång i den slutgiltiga 3D-modellen. Den resulterade 3D-modellen ger en bra överblick över den generella geologin som påträffas i File hajdar området. Praktisk tillämpning av 3D-modellen kan exempelvis innefattar vidare tänktplanering eller fortsatt utvärdering av området genom implementering av mer data. Baserat på 3D-modellen framställs två förslag på lokaler lämpliga för vidare undersökningar. Motsvarande placeringarna av de norra- och nordvästra rekvkropparna tolkas dessa utgöra potentiella områden för kalkbrytning och i behov av ytterligare undersökning.

This work aimed to investigate the groundwater situation in and around Mina din Chisinau, an underground limestone mine in Chisinau, Moldova, in order to contribute to a sustainable solution to its flooding problem. Work on-site was done including visits inside the mine, to points of hydrogeological relevance to the mine, well inventories/search, and an attempt at an infiltration test. An on-site literature study was done using printed materials as well. Water quality in the mine and locally was examined. A GIS interpolation of groundwater levels was done and groundwater flow was visualized. Groundwater flow locally is thought to be in the west-southwest direction. Water quality is good but high in minerals, making it suitable for blending with surface water. A proposed project to pump groundwater from outside the mine to the municipal drinking water system seems to be a suitable solution, however groundwater modelling, ideally based on pumping tests, should be done to inform the system dimensions and design. / Detta arbete syftade till att undersöka grundvattensituationen i och runt Mina din Chisinau, en underjordisk kalkstensgruva i Chisinau, Moldavien, för att bidra till en hållbar lösning på dess översvämningsproblem. Arbetet på plats utfördes inklusive besök i gruvan, till punkter av hydrogeologisk relevans för gruvan, brunnsinventeringar och ett försök till ett infiltrationstest. En litteraturstudie på plats gjordes också med tryckt material. Vattenkvaliteten i gruvan och lokalt undersöktes med hjälp av befintligt resultat. En GIS-interpolering av grundvattennivån gjordes och grundvattenflödet visualiserades. Grundvattenflöde tros vara lokalt i väst-sydvästlig riktning. Vattenkvaliteten är god men mineralrik, vilket gör den lämplig för blandning med ytvatten hos vattenverket. Ett föreslaget projekt för att pumpa grundvatten från utanför gruvan till det kommunala dricksvattensystemet verkar vara en lämplig lösning, men grundvattenmodellering, helst baserat på pumptester, bör göras för att informera systemets dimensioner och design.

Calcination is important for modern society as we know it since products from the reaction is used inseveral industries. Calcination is a chemical reaction where a solid particle, e.g., limestone, is exposedto high temperature which causes volatile impurities to be released from the particle.One of the main challenges with lime production is the mere scale of commercial production. Ensuringgood calcination and high-quality lime in laboratory scale is relatively easy, whereas commercial limekilns produce 100 – 800 tons lime each day, causing the conditions to be much more challenging. Theenvironment inside a lime kiln is extreme, with temperatures exceeding 1200°C, and a moving stonebed makes measurements difficult to perform. To obtain information about the calcination processand the extreme environment that arises in commercial lime kilns, companies and researchers havedeveloped simulation programmes to evaluate how changes in ambient condition affect the calcinationprocess.In this project, a shrinking core model has been used to simulate calcination of limestone with variedgeometry and size in different ambient condition. A transient model was used to simulate the heatingphases before and after the calcination phase. The results obtain from the simulation are compared tomeasured data obtain by others.There are many similarities between the measured data and the simulation, a reoccurringphenomenon is that the transit model, during the pre-heating, heats the limestone faster compared tothe measured data. However, in one case, the transient model is slower. A reason for this may be thatthe transient model does not account for morphological effects, as they are included in the heattransfer coefficient instead, such as the thermal conductivity coefficient and specific heat transfercoefficient. The post heating phase, after the reaction phase, required further work.The simulation with the Shrinking core model shows that a cylindrical geometry requires longercalcination duration, or a higher ambient temperature compared to a spherical geometry, even if bothgeometries have same material properties and radius. The factor with the most influence uponcalcination time is the ambient temperature in combination with reaction temperature. A highercarbon dioxide pressure, above atmospheric CO2 partial pressure, has relatively small effect comparedto a low ambient temperature, less than 1000°C.

Limestone is a raw material in the cement and quicklime industry and knowledge about limestone characteristics can help improve and optimize production processes. In the end this can lead to a reduction in CO2 emissions from the industry. In this project X-ray tomography (XRT) was used to examine limestone samples. The aim was to determine if XRT, including synchrotron-based XRT, is a reliablemethod to determine porosity, pore structure and internal distributions of pores and pyrite (FeS2) grains in limestone. The aim also included to determine if XRT could be used to resolve material variations, fine-grained and larger crystals in limestone. In total, there were ten limestone samples and the performed XRT was done by Advanced Light Source (ALS) in Berkeley, California and by Luleå University of Technology. A brief comparison between ALS and Luleå was also done by inspectingsamples that have been through XRT at both facilities. The main software used foranalysis was Avizo v.9.2.0. The results showed that XRT is a suitable method for determining porosity and pore distribution. Interactive thresholding was used in Avizo for measuring porosity. The porosity was determined as a single value and as a narrow range, where a narrow range was more reliable. XRT was also found to be a suitable method for visually determining a variety of textures within the samples. Areas with different materials(such as dolomite) and/or newly-formed crystals were visually distinguishable but individual newly-formed crystals were not as clear when compared to scanning electron microscopy. Individual older fine-grained and larger crystals were hard to resolve. Internal distributions in 3D of both pores and pyrite grains were possible to obtain with XRT. The analysis of internal distributions was found to be a clear advantage with the method of XRT. The equivalent diameter of pores and pyrite grains was also measured and plotted in histograms. The XRT performed at ALS had higher resolution than the XRT performed in Luleå (0.65 vs 2 μm). Lower resolution over-estimated the average equivalent diameter of pores, and boundaries of pores and cavities were harder to see. Therefore, the higher resolution from ALS was preferable. These results contribute to understanding limestone characteristics.

Rota Island, the southernmost island in the Commonwealth of the Northern Mariana Islands in the western Pacific, has the types of caves previously documented on the other limestone mantled islands in the Mariana Arc that have been investigated for caves: Aguijan, Guam, Tinian and Saipan. Caves developed at the edge of the fresh-water lens by zones of enhanced carbonate dissolution produced by fresh-water/salt-water mixing are most common. Among these mixing zone caves, flank margin caves dominate. Flank margin caves were found singly and in extensive horizons representing significant sea-level still stands. However, another type of mixing zone cave was found on Rota in numbers not documented on neighboring islands. Mixing zone fracture caves, apparently formed as zones of enhanced dissolution, produced fresh-water discharging from the lens along fractures, migrated vertically as sea-level changed. Some mixing zone fracture caves on Rota are developed in clusters from two to four caves. The mixing zone caves of Rota reflect the interaction of eogenetic limestone, glacioeustasy, local tectonics and enhanced carbonate dissolution via mixing of disparate waters. The development of mixing zone caves on Rota is in agreement with the Carbonate Island Karst Model (CIKM). Rota has a few caves developed along the contact between limestone and the insoluble volcanic rock that makes up the core of the island. The most important of these is Water Cave, a large spring that is the source for most of the municipal water on Rota. Rota also two extensive zones of vertical fissures developed along bedrock fractures; Fissure City and As Mundo Fissure Zone. In addition, Rota has one cave apparently developed along a fault; Gagani Cave. Some of the caves documented on Rota are difficult to classify and warrant further investigation.

No description available.

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