De två kemiskt nära besläktade metallerna niob (Nb) och tantal (Ta) räknas av Europakommissionen som kritiska råmaterial. Detta på grund av en kraftigt ökad efterfrågan och en geografiskt koncentrerad global produktion av dem. Det här arbetet utgör en del av ett större projekt som bedrivs av EuroGeoSurveys (EGS); GeoERA FRAME, som har till syfte att kartlägga förekomsten av kritiska råmaterial inom EU. Två granitpegmatitiska prov från Kolsva fältspatgruva har undersökts med avseende på deras kemi och mineralogi; dels sådana som tentativt identifierats som kolumbitmineral och dels sådana som innehåller ett samarskitliknande mineral. I arbetet har tre huvudsakliga analysmetoder använts: 1) optisk mikroskopi, 2) svepelektronmikroskopi (SEM) med energidispersiv mikrokemisk analys (EDS), samt 3) pulverröntgendiffraktionsanalys (XRD). De kemiska analyserna som genomfördes på ”kolumbit-proven” visade att de bestod av kolumbit-(Fe), med generell formel AB2O6 och med en järndominans i A-katjonposition och niobdominans i B-katjonposition. Analyserna visad även på förekomst av mineral tillhörande pyroklorsupergruppen. De samarskitartade mineralen uppvisade en partiell likhet med samarskitgruppmineral (generell formel ABO4), men med hög grad av metamiktisering, dåliga stökiometrier, låga REE-halter, samt med varierande järn- och kalciumdominans i tentativ A-katjonposition och niobdominans i B-katjonpositionen. Även aluminiumsilikater, mineral från spinellgruppen samt hematit påvisades. Uppsprickning av de metamikta och spröda samarskitartade mineralen har möjliggjort en fluidmedierad omvandling, vilket bl.a. lett till bildning av sekundär radiogen blyglans. Resultaten av undersökningarna bekräftar att Kolsvapegmatiten representerar ett lokalt niob-tantalmineraliserat system. / The two chemically related metals niobium (Nb) and tantalum (Ta) are classified by the European Commission as critical raw materials. This is due to a highly increased demand and a limited global supply situation for these metals. This work is a part of a larger project run by EuroGeoSurveys (EGS); the GeoERA FRAME, which aims to map the distribution of critical raw materials in the EU. Two granitic pegmatite samples from the Kolsva feldspar mine were studied with regards to their chemistry and mineralogy. They had been tentatively identified as consisting of a columbite mineral and a samarskite-like mineral, respectively. In the project, three main analytical methods have been used: 1) optical microscopy, 2) scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS), and 3) powder X-ray diffraction analysis (XRD). The analyses performed on the “columbite samples” indicated that most of them were columbite-(Fe), general formula AB2O6, with an iron dominance in the A-cation position and niobium dominance in the B-cation position. The analyses also indicated the presence of minerals belonging to the pyrochlore supergroup. The analyses of the samarskite-like minerals yielded results showing a partial resemblance to the samarskite group minerals (general formula ABO4), but with a high degree of metamictisation, poor stoichiometries, low to very low REE contents, variable iron and calcium-dominance in a tentative A-cation position and niobium-dominance in the B-cation position. Aluminium silicates, minerals from the spinel group and hematite were also observed in this assemblage. Fracturing of the brittle, metamict samarskite-like minerals have enabled a fluid-mediated alteration, which a.o. led to the formation of secondary radiogenic galena. The study confirms that the Kolsva pegmatite represents a locally Nb-Ta mineralised system.

Abstract Mineralogical-mineral chemical characterisation of Nb-Ta-bearingassemblages from the Stripåsen granitic pegmatite, NorbergJens Henriksson The occurrence of Nb-Ta-bearing minerals has earlier been briefly documented inthe Stripåsen granitic pegmatite, Norberg, central Bergslagen. This report describesthe background, preparation and basic characterisation of sampled Nb-Ta-bearingmineral assemblages from this pegmatite. These comprise (Y,REE,U,Th)-(Nb,Ta,Ti)-oxides of mainly a tantalum-dominated A 2-m B 2 X 6-w Y 1-n -type, belonging to the pyrochloresupergroup. The major primary mineral is suggested to have been afluorcalciomicrolite, ideally (Ca,Na,☐) 2 Ta 2 O 6 F. In association with abundant fractureformation related to metamictisation of the microlite minerals, they are interpreted tohave been variably altered by late-stage fluids. Thus, the system has beenextensively modified after the primary crystallisation of the pegmatite melt. Besidesthese (Y,REE,U,Th)-(Nb,Ta,Ti)-oxides, monazite-(Ce) ((Ce, LREE)PO 4 ), nativebismuth (Bi) and presumably radiogenic galena (PbS) were identified. The sampleshave mainly been studied by means of scanning-electron-microscopy with energydispersive spectroscopy (SEM-EDS), utilising reflected polarised light microscopy asa complementary tool. The study was done within the framework of the EU-supported FRAME-project which is focused on a selection of metals and minerals,among others niobium (Nb) and tantalum (Ta). / Sammanfattning Mineralogisk-mineralkemisk karakterisering av Nb-Ta-förande associationerfrån Stripåsenpegmatiten, NorbergJens Henriksson Förekomsten av Nb-Ta-förande mineral har tidigare dokumenteras iStripåsenpegmatiten, Norberg, centrala Bergslagen. Här redogörs för bakgrund,provförberedelse och grundläggande karakterisering av provtagna Nb-Ta-förandemineralassociationer från denna pegmatit. Proven som undersökts innehåller(Y,REE,U,Th)-(Nb,Ta,Ti)-oxider av främst tantaldominerad A 2-m B 2 X 6-w Y 1-n -typtillhörande pyroklorsupergruppen. Den huvudsakliga primära fasen tolkas ha varit enfluorkalciomikrolit, idealiskt (Ca,Na,☐) 2 Ta 2 O 6 F. I anslutning till rikligt förekommandesprickor som är relaterade till omfattande metamiktisering har mikroliternaomvandlats i varierande grad av sena fluider. Systemet har alltså förändrats kraftigtefter den primära kristallisationen av pegmatitsmältan. Förutom (Y,REE,U,Th)-(Nb,Ta,Ti)-oxider identifierades monazit-(Ce) ((Ce,LREE)PO 4 ), gedigen vismut (Bi)och vad som sannolikt är radiogen blyglans (PbS). Provmaterialet har huvudsakligenundersökts med genom svepelektronmikroskopi med energidispersiv spektroskopi(SEM-EDS), varvid malmmikroskopi har använts som ett kompletterande verktyg.Studien gjordes inom ramverket för det EU-stödda FRAME-projektet som blandannat fokuserar på förekomster av de kritiska och konfliktrelaterade metallerna niob(Nb) och tantal (Ta).

Un des enjeux majeurs en Sciences de la Terre est la compréhension des mécanismes de déformation de la lithosphère continentale dans des zones de convergence. Le plateau Tibétain constitue un laboratoire naturel idéal pour l'étude des processus crustaux profonds actifs dans ces contextes, du fait de sa superficie et de son altitude remarquables. Le soulèvement et l'épaississement de la croûte Tibétaine ont été classiquement attribués aux effets de la collision Inde-Asie Tertiaire. Cependant, cette interprétation a été récemment mise en question par une série d’observations géologiques et géophysiques non concordantes, à différents endroits du plateau.L'objectif de cette thèse est de quantifier l’importance de l’héritage géologique dans la déformation à long-terme et à court-terme d’une chaîne active, en déchiffrant les différentes étapes de la structuration des Longmen Shan, la bordure la plus énigmatique du plateau Tibétain. Dans la chaîne des Longmen Shan la croûte Tibétaine est très épaissie (>60 km) et l'activité tectonique est localisée le long des failles d’échelle lithosphérique, comme démontré par les séismes de Wenchuan 2008 (Mw 7.9) et de Lushan 2013 (Mw 6.6). Un fort gradient topographique est présent, bien que les taux de convergence mesurés par GPS soient très faibles (<3 mm/an). Ces caractéristiques ne sont pas explicables par un modèle unique de déformation crustale, ce qui suggère une forte contribution de l'héritage géologique acquis avant la collision Inde-Asie dans la structure actuelle de la chaîne.Une étude pétro-chronologique qui combine des observations microstructurales avec la cartographie chimique des minéraux majeurs et accessoires, la modélisation thermodynamique et la datation in-situ par méthode 40Ar/39Ar et U-Pb/Th sur mica et allanite a été appliquée aux roches métamorphique à l’affleurement de chaque côté des faille majeures. L’analyse haute résolution montre que les minéraux métamorphiques dans la matrice des sédiments à grenat provenant des unités internes de la chaîne préservent dans leur composition le témoignage de différentes étapes du métamorphisme. Ceci s’explique par un rééquilibrage chimique incomplet en raison de la variabilité des fluides disponibles au cours du métamorphisme. Les différentes étapes du métamorphisme sont aussi enregistrées dans le signal 40Ar/39Ar des micas et dans la composition des minéraux accessoires.La compréhension des processus pétrologiques à petite échelle a été intégrée aux observations de terrain afin de quantifier l’épaississement de la croûte Tibétaine au Mésozoïque (> 30 km) et de mettre en évidence un saut métamorphique >150°C à travers les failles majeures, hérité de la tectonique Mésozoïque. Si les unités internes de la chaîne ont été fortement déformées, découplées du socle cristallin et métamorphisées à T ~580-600°C (P ~11 kbar), les unités externes apparaissent moins déformées et épaissies (T< 400°C, P< 5 kbar). Une exhumation partielle du socle depuis c. 20 km de profondeur a été également documentée à 120-140 Ma et reliée à un évènement tectonique méconnu auparavant.Cette thèse a ainsi permis de quantifier la durée et les conditions qui caractérisent les différentes étapes de la maturation de la chaîne: les unités internes atteignent la relaxation thermique 40 Ma après le début de la propagation du prisme orogénique. Le socle est réactivé 40 Ma plus tard, lorsqu’il atteint des conditions thermiques proches de celles de sa couverture sédimentaire. L’héritage géologique Mésozoïque contrôle fortement l’état thermique et rhéologique de la croûte supérieure au moment de la réactivation Cénozoïque ainsi que la structure actuelle de la chaîne.L’étude petro-chronologique de différents segments de la chaîne a aussi mis en évidence une segmentation métamorphique héritée du Mésozoïque qui correspond à la segmentation actuelle des failles. Ceci suggère que des structures héritées pourraient en partie contrôler la localisation des séismes récents. / One of the major challenges in Earth Sciences is understanding how the continental lithosphere deforms in convergent settings, according to which timescales. For its elevation and extension the Tibetan plateau is an ideal natural laboratory for the study of deep crustal processes in active convergent settings. The rise and thickening of the Tibetan plateau has generally been related to the only collision between the Eurasian and Indian plates during the Cenozoic. However, this interpretation has been recently put into question by apparently contrasting geophysical and geological features observed at different locations on the plateau.The aim of this PhD is to quantify the importance of the geological inheritance in the long-term and short-term deformation of an active thrust belt, focusing on the Longmen Shan orogen, the most enigmatic border of the Tibetan plateau. In the Longmen Shan (eastern Tibet) the Tibetan crust is over thickened (>60 km), the tectonic activity is localized along lithospheric faults -as demonstrated by the occurrence of the Mw 7.9 Wenchuan (2008) and Mw 6.6 Lushan (2013) earthquakes- and a high topography survives despite low convergence rates measured by GPS (<3 mm/yr). These observations are hardly reconcilable in a unique model of crustal deformation, suggesting a contribution of the geological inheritance from the geological history preceding the India-Asia collision.A petro-chronological approach that combines microstructural observations, compositional mapping of major and accessory mineral phases, thermodynamic modelling, in-situ 40Ar/39Ar dating, Ar diffusion modelling and in-situ U/Pb-Th allanite dating was applied to metamorphic rocks on each side of the major faults that strike parallel to the belt. This high-resolution study shows that in garnet-bearing rocks of the internal units of the belt matrix minerals record different stages of the metamorphic path in their composition. This is due to an incomplete chemical re-equilibration explained by a variable fluid availability during metamorphism. Different stages of metamorphism and fluid-assisted reactions sequences are also recorded in the 40Ar/39Ar signal of micas and in the composition and textures of the accessory phases.The understanding of petrological processes at the small scale was combined with field observations to quantify the Mesozoic thickness of the Tibetan crust at > 30 km and to unravel a metamorphic jump of greater than 150°C across the major faults, inherited from the Mesozoic tectonics. While internal units of the belt were strongly deformed, decoupled from the basement and metamorphosed at T ~ 580-600°C (P ~11 kbar), external units were less deformed and experienced lower temperatures conditions (T < 400°C, P < 5 kbar). The partial exhumation of the crystalline basement from c. 20 km depth along the major fault (in both internal and external units) occurred at c. 120-140 Ma during a previously poorly documented tectonic event.The multi-method approach applied on a wide geographical area and on a large time interval enabled to quantify the rates and conditions of the different stages of the maturation of the belt; internal units reached the thermal relaxation at ~600°C 40 Ma after the beginning of the propagation of the orogenic load. The basement was re-activated 40 Ma later, at similar thermal conditions than its sedimentary cover. The Mesozoic geological inheritance is therefore a key element in the present structure of the belt and strongly controlled the rheological and structural state of the upper crust at the moment of the Cenozoic re-activation.The petro-chronological study of different segments of the belt showed an along-strike metamorphic segmentation of the Longmen Shan inherited from the Mesozoic. This segmentation corresponds to the present fault segmentation, underlying the potential role of inherited structure in controlling the geographic distribution of the recent earthquakes.

Bergslagen är känt för sin mångfald av mineraliseringar liksom sällsynta element och mineral. Speciellt pegmatiter och vissa skarnförekomster har förhöjda koncentrationer av sällsynta jordartsmetaller (REE på engelska) och REE-förande mineral. Pegmatitprover från Flintgruvan, som ligger i norra Bergslagen (Dalarna), karakteriserades i den här studien. Proven som studerades innehöll flera REE-förande mineral; (Y,REE,U,Th)-(Nb,Ta,Ti)-oxider av AB2O6-typ, xenotim-(Y) och (Y,Yb)-förande thorit. Pegmatiten klassificerades som varandes av NYF-(Niob-Yttrium-Fluor) typ på grund av de förhöjda koncentrationerna av niob (Nb), yttrium (Y) och titan (Ti) i de undersökta faserna. Förutom yttrium så innehöll pegmatiten små koncentrationer av andra HREE (tunga sällsynta jordartsmetaller) som ytterbium (Yb) och dysprosium (Dy). (Y,REE,U,Th)-(Nb,Ta,Ti)-oxiderna innehöll även relativt höga halter av kisel (Si). På basis av de kemiska analyserna representerar dessa strakt omvandlade faser antingen aeschynit eller polykras som ursprungsmineral. Undersöknings- och analysmetoderna som användes i studien var polarisationsmikroskopi och svepelektronmikroskopi med energidispersiv spektroskopi (SEM-EDS). / Bergslagen is known for its diversity of rare elements and minerals. Especially granitic pegmatites and some uncommon types of skarn deposits have shown higher concentrations of rare earth elements (REE) and REE-bearing minerals. Samples of a granitic pegmatite from Flintgruvan, which is located in northern Bergslagen (Dalarna), were characterized in this study. The samples that were studied were found to contain several REE-rich minerals such as (Y,REE,U,Th)-(Nb,Ta,Ti) oxides of AB2O6 type, xenotime-(Y) and an Y+Yb-bearing thorite. The most abundant AB2O6 type oxides were found to represent strongly altered minerals, either belonging to the aeschynite or polycrase group. Based on mineral chemical studies, the pegmatite was classified as being of the NYF (Niobium-Yttrium-Fluorine) type due to the predominance of yttrium (Y) and niobium (Nb) as well as notable titanium (Ti) concentrations. Other than yttrium the samples contained small concentrations of other HREE (heavy rare earth elements) such as ytterbium (Yb) and dysprosium (Dy). The (Y,REE,U,Th)-(Nb,Ta,Ti) oxides also contained a relatively high content of silicon (Si). The mineralogical characterization was done by means of reflected polarized light microscopy and scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS).

A large number of Building Services Engineering (BSE) graduates from UK universities either already live and work abroad, or aspire to do so, and the destinations for such migrants are most often English-speaking countries or countries where English is commonly used in business. Academic programmes in BSE are usually professionally accredited by the Chartered Institution of Building Services Engineers (CIBSE) under licence from the Engineering Council (EC). In the common destination countries for UK BSE graduates the Washington, Sydney and Dublin Accord (WSDA) agreements prevail, meaning that there is a mutual recognition of engineering qualifications and professional accreditation of academic courses, and this facilitates international mobility. Since it is widely accepted that buildings account for as much as 50% of greenhouse gas emissions worldwide, it could be said that there is a worldwide sustainability agenda with respect to buildings. The common factor across national boundaries is that Building Services Engineers, as central members of building design teams, must provide much of the specialist practical knowledge to enable more energy efficient buildings to be designed and constructed, and it is therefore likely that UK educated engineers will be working in far more varied overseas locations in the near future. The main aim of the work is to synthesise an education and training model to encourage and enable international mobility of UK BSE graduates, and to carry out some evaluation of this model. This work sets out initially to question whether a UK education in BSE necessarily provides UK graduates with the best possible skillset for work abroad. The influence of the EC upon the content of BSE study programmes has been examined, and the research assesses the benefits of the EC’s influence in countries with different economic and political priorities to the UK, other western economies and to the WSDA countries. Following identification and analysis of the main issues, the model was constructed and evaluations were made using semi-structured interviews. The methodology used in this research is necessarily underpinned by a pragmatist paradigm, which has led to the use of a mixed methods blended approach. In addition to thorough review and analysis of literature, the practical methods employed include a questionnaire survey and semi-structured interviews in three phases: an exploratory phase, an in-depth analysis, and a concluding phase. The early conclusions indicated that the EC influence upon BSE study programmes is generally regarded as necessary and beneficial, since it provides an engineering skillset that is internationally respected and recognised. There is, however, less confidence in applying this in an international arena outside of the WSDA umbrella since different parts of the world face different economic challenges, divergent societal imperatives, and diverse attitudes to sustainability and green issues. An education and training model was constructed to address these issues and, after initial testing, was found generally to be a workable proposition to enhance the international prospects of UK BSEs, and further, could be adopted in the UK under the auspices of the Degree Apprenticeship initiatives. Such a model is, however, unlikely to be adopted in many overseas locations due to differing cultural views on the value of work-based learning and apprenticeship.

Percevoir signifie recevoir une information, la prendre en compte, la confronter aux données de notre mémoire et la traiter selon nos modes de raisonnement puis tirer de l’image ainsi formée une conséquence c’est-à-dire un acte. Pour approcher la perception de l’islam par les élites françaises entre 1830 et 1914 nous avons donc dans un premier Livre fait une compilation des présentations que les élites dites « d’érudition » : historiens, écrivains, religieux, linguistes, philologues, artistes, faisaient de l’islam ; des données qu’ils pouvaient recevoir de leur mémoire puisque l’on glosait sur l’islam depuis Pierre le Vénérable ; et des modes de raisonnement qui caractérisaient l’époque en étudiant l’évolution du sens des concepts de civilisation, de race, d’économie politique. Nous avons ensuite, dans un deuxième Livre essayé de comprendre comment et pourquoi l’image ainsi formée avait abouti à la colonisation de terres islamiques par des hommes politiques, leurs conseillers, leurs soutiens, des officiers, des industriels, des financiers, et des administrateurs. Enfin, dans un troisième Livre, nous avons tenté de suivre jusqu’à nos jours les jugements portés sur ces travaux orientalistes. Il nous semble que le traitement d’une image, au départ volontairement tronquée, par des hommes persuadés que les techniques - balbutiantes - des sciences de la nature pouvaient être appliquées aux sciences humaines a conduit à une incompréhension de deux mondes. / Perceiving means to receive an information, to take it into account, to compare this information with the data from our memory, to process it according to our ways of thinking and then to pull from the image thus formed a consequence, that is to say: an act. To approach the perception of Islam by the French elites between 1830 and 1914, we initially, in our first book, made a compilation of presentations that "scholarship" elites - historians, writers, religious, linguists, philologists, artists - made of Islam; of the data they could receive from their memory, since we talked about Islam since Peter the Venerable; and of these ways of thinking that characterized the era by studying the evolution of the meaning of concepts like civilization, race, and political economy. We then, in a second book attempted to understand how and why the thus formed image had resulted in the colonization of Islamic lands by politicians, their advisors, their supporters, officers, industrialists, investors and administrators. Finally, in a third book, we tried to follow to this day the judgements that are made about these orientalist works. It seems to us that the process of an image, deliberately, and from the beginning, truncated by men convinced that early techniques of natural science could be applied to human sciences has led to a misunderstanding of both worlds.

Let P = (p1, p2, . . . , pN ) be a sequence of points in the plane, where pi = (xi, yi) and x1 < x2 < · · · < xN . A famous 1935 Erdős-Szekeres theorem asserts that every such P contains a monotone subsequence S of √ N points. Another, equally famous theorem from the same paper implies that every such P contains a convex or concave subsequence of Ω(log N) points. First we define a (k + 1)-tuple K ⊆ P to be positive if it lies on the graph of a function whose kth derivative is everywhere nonnegative, and similarly for a negative (k + 1)-tuple. Then we say that S ⊆ P is kth-order monotone if its (k + 1)- tuples are all positive or all negative. In this thesis we investigate quantitative bound for the corresponding Ramsey-type result. We obtain an Ω(log(k−1) N) lower bound ((k − 1)-times iterated logarithm). We also improve bounds for related problems: Order types and One-sided sets of hyperplanes. 1

Pour comprendre l'évolution tectono-métamorphique des unités de type Thiviers-Payzac dans la chaîne hercynienne, trois secteurs d'études ont été choisis: le Rouergue-Albigeois, le Quercy et la Vendée. Ces études pétrostructurales et géochronologiques ont permis de présenter l'évolution tectonique suivante:<br /> Au Dévonien moyen, un premier épisode provoque le charriage vers le SW de l'Unité Supérieure des Gneiss sur l'Unité Inférieure des Gneiss. Dans le Rouergue, les granites syntectoniques ont aussi enregistrés cette déformation. Vers 360 Ma, un deuxième épisode tangentiel provoque le charriage des unités de type Thiviers-Payzac vers le NW en contexte métamorphique barrovien. Lors d'une troisième phase vers 330 Ma, les unités précédemment structurées sont charriées vers le Sud sur l'ensemble Albigeois-Montagne Noire. La signification du deuxième épisode est également discutée en termes de géodynamique.

L'évolution tardive du Domaine Sud Armoricain (segment de la chaîne Varisque Ouest Européenne), se traduit par un effondrement gravitaire de la croûte préalablement épaissie dans un contexte tectonique extensif. Cette extension s'accompagne, dans tout le domaine, d'une fusion partielle de la croûte moyenne à inférieure et de l'exhumation des roches métamorphiques issues de niveaux crustaux profonds. L'approche pluridisciplinaire conduite dans cette étude permet de proposer un calendrier précis de la fusion crustale et d'étudier les mécanismes de la déformation responsable de l'exhumation de la croûte moyenne à inférieure. Une des démarches adoptées associe l'identification structurale et cinématique précise des témoins de l'étirement et leur datation multiméthodes (U-Th/Pb sur monazite, et A/Ar sur micas). Dans la partie occidentale du Domaine Sud Armoricain, cette approche permet ainsi de documenter un continuum de déformation extensive durant plus de 20 Ma, qui accompagne en partie l'exhumation des roches de haut grade qui elle, se développe entre 325 Ma et 300 Ma. L'étude géophysique, combinant ASM et gravimétrie, permet en outre de caractériser la structure interne et la géométrie en profondeur du complexe granitique de Carnac, dont la mise en place apparaît être le témoin du stade le plus précoce de ce continuum. La fusion partielle des migmatites et la mise en place des plutons granitiques, interprétées à la fois comme le moteur et la conséquence de l'étirement et de l'exhumation, est estimée entre 335 Ma et 320 Ma. Cette anatexie généralisée apparaît synchrone à l'échelle de tout le domaine, ce qui permet un regard nouveau sur les stades tardi-orogéniques du Domaine Sud Armoricain. L'étude de la déformation extensive et de l'exhumation dans les portions occidentale et orientale, met en évidence des contrastes de style tectonique, suggérant une exhumation plus importante des parties orientales du Domaine Sud Armoricain.

The aim of this study has been to clarify how the radiumdistribution in soils affects the radon emanation. Thedistribution of radium, uranium and thorium has been determinedusing sequential extractions. In the study, soils from twodifferent locations were investigated. In the first part the applicability of the sequentialextraction method for determining Ra distribution in differentsoil types was investigated, using a simple sequentialextraction method. Sampled soils were clay, sand and till fromthe vicinity of the Stockholm Esker. The main part of Rnemanating Ra was associated with Fe oxides in the soil. Themethods applied provided information about the radon risk ofthe soil, but, inorder to gain more information on theprocesses governing Ra distribution and radon emanation insoils, a more detailed sequential extraction procedure would bedesirable. The second part consisted of a detailed study of theradionuclide distribution and the geochemistry in a podzolisedglacial till from Kloten in northern Västmanland. A moredetailed sequential extraction procedure was used, and thespecific surface area of samples was measured. Samples weretaken from E, B, and C horizons; radium and thorium wereenriched in the B horizon, whereas uranium had its maximumconcentration in the C horizon. Extractable radium primarilyoccurred in the exchangeable pool, possibly organicallycomplexed, whereas extractable uranium and thorium were mainlyFe oxide bound. Oxide-bound Ra was important only in the Bhorizon. The radon emanation was not correlated with the amountof exchangeable Ra, but instead with the oxide bound Ra.However, the amount of oxide-bound Ra was too small to accountfor all the emanated Rn, thus, exchangeable Ra was interpretedas the main source of emanated Rn. This exchangeable Ra wasmore emanative in the B horizon than in the C horizon. Theexplanation is the larger surface area of the B horizonsamples; the specific surface area appears to be the maingoverning parameter for Rn emanation in this soil. The surfacearea is largely created by the precipitation of amorphous Feoxides, thus, Fe oxides has a significant effect on Rnemanation. Comparing the two studies, the Stockholm samples had thesame amounts of oxide-bound Fe and surface-bound Ra. Still theradon emanation was much smaller for these samples than in theKloten soil. The amount of organic matter in the B horizon ofthe Kloten soil is however, much larger than the organic mattercontent in the Stockholm samples. It is suggested that thelarge Rn emanation in the B horizon of Kloten is caused by thecombined effect of Fe oxides and organic matter. The variability of226Ra distribution in soils was also investigated.The226Ra distribution was determined for samples from60-70 cm and 80-90 cm depth, from three adjacent soil profilesin a podzolic glacial till. Ra distributions, and estimationsof Rn risk based on the Ra distributions, of a single soilprofile, are likely to be representative for a similar area,provided that the samples are taken from a sufficientdepth. KEYWORDS: distribution, emanation, extraction, glacial till,podzol, Ra, radium, radon, Rn, sequential soil, spodosol, Th,thorium, U, uranium, variability