Unconformity-type uranium deposits from the Athabasca Basin are considered to be the result of mixing between oxidized basinal brines and basement-derived reduced fluids/gases, and/or reduced basement rocks. Graphite and/or its breakdown products are suggested to be responsible for uranium mineralization by acting as a reductant that could trigger deposition of uranium. Also, graphite is considered to be indicative of basement structures; being often concentrated along structures which can be identified as electromagnetic (EM) conductors. Thus, exploration for uranium deposits is often focused on the search for EM conductors. Underlying the sedimentary rocks of the basin in the Dufferin Lake zone are variably graphitic pelitic schists (VGPS); altered to chlorite and hematite (Red/Green Zone: RGZ), and locally bleached equivalents near the unconformity during paleoweathering or later fluid interactions. These altered zones are texturally similar rocks within “graphite-depleted zones” as the unconformity is approached. Both zones are characterized by a lower concentration of carbon and sulfur, with the bleached zone showing higher concentrations of uranium and boron, the latter corresponding to high dravite content. The major element composition of the graphite-bearing pelitic schists and altered equivalents (RGZ) are similar. Raman analyses indicate that well-ordered carbon species (graphite to semi-graphite) are present in the pelitic schists, with both types more common within shear zones. In contrast, only rare low-ordered carbon species (carbonaceous matter) were detected in the graphite-depleted samples within the RGZ. This variation is interpreted to be the result of graphite consumption by oxidizing fluids migrating downward from the Athabasca Group. This graphite consumption may have resulted in the production of a mobile reductant (gas or fluid), which may have played a subsequent role in the deposition of uranium mineralization. Secondary fluid inclusions (FI) examined in different quartz vein generations using microthermometry and Raman analysis, provide an indication of the fluids that have interacted with these rocks. Monophase vapor are the dominant type of fluid inclusions in the VGPS, whereas aqueous two-phase (L+V) and three-phase (L+V+Halite) FI occur in the RGZ. CH4-dominant and N2-dominant FI identified using Raman could be the result of fluid(s) interaction with the graphitic lithologies. This would have generated the breakdown of graphite to CH4 and associated feldspars/micas to NH4/N2. CH4, N2 and H2 (resulting from the decomposition of NH4+) represent possible reductants of uranium-bearing brines. Two brines in the RGZ: a regional basinal fluid and an evolved fluid possibly related to U mineralization; similar to other nearby deposits, are observed. These suggest that the basinal brines have circulated in the basement rocks and have been able to evolve by interaction with the basement rocks to possibly be related to uranium mineralization.

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Cette thèse passe en revue certains facteurs de risques économiques (risque de revenu, risque de la finance parallèle, et risque carbone) en utilisant de nouvelles sources de données et méthodologies. Le premier chapitre examine comment la réponse de la consommation face au risque de capital humain affecte la finance des ménages. A partir de données conjointes sur la consommation, les revenus et les actifs des ménages américains, ce papier documente le lissage excessif de la consommation comme un facteur essentiel pour le choix de portefeuille et montrer qu’il peut expliquer les énigmes financières observées chez les ménages américains. Par ailleurs, le papier formalise l’effet du lissage excessif sur le choix de portefeuille à l’aide d’un modèle de cycle de vie où un ménage est confronté à un risque de revenu salarial idiosyncratique. Le modèle est calibré de façon à correspondre aux observations sur le cycle de vie de la détention d’actifs risqués des ménages américains. Le deuxième chapitre évalue le transfert de risques des banques dans les activités bancaires non réglémentées. En exploitant les variations dans les risques discutés par les banques dans leur rapports financiers et en utilisant les outils de l’analyse textuelle, ce document fournit une nouvelle mesure de l’activité bancaire non-réglementée. Le papier montre empiriquement que (1) les banques sont plus susceptibles de contourner les régulations lorsque leurs contraintes de fonds propres deviennent contraignantes, (2) il existe une relation positive entre le transfert de risque et le risque extrême des banques. Par la suite, le papier rationalise ce transfert de risque en utilisant un modèle macroéconomique avec un secteur financier. Dans le modèle, l’événement de défaut de paiement et la présence d’externalités dues à une application imparfaite de la réglementation encourage les banques à s’engager dans une stratégie de transfert des risques. Enfin, le papier utilise ce cadre pour étudier la régulation optimale. On montre qu’une taxe sur l’activité sectorielle réduit efficacement le transfert des risques des banques par rapport à d’autres politiques comme la réglementation des fonds propres de la banque. Enfin, le troisième chapitre aborde l’effet du risque carbone sur la stabilité économique. Nous étudions ce risque à l’aide de données de panel pour 50 États américains au cours des années 1998 à 2018. De plus, nous supposons une dépendance transversale des facteurs communs non observés (par exemple, les liens commerciaux, l’intégration financière) entre les États. En utilisant une approche d’émissions de carbone basée sur la consommation, ce chapitre montre qu’une diminution d’une unité des émissions de carbone est associée, à long terme, à une croissance de la production logarithmique par habitant de 4,5 points de pourcentage. En outre, nous trouvons des impacts différentiels dans la distribution du revenu par habitant des États. Ces résultats éclairent le débat sur la voie de transition optimale vers une économie sobre en carbone. / This thesis reviews some economic risk factors (labor income risk, shadow banking risk, and carbon risk) using new data sources and novel methodologies. The first chapter investigates how the response of consumption to human capital risk affects household finance. Using joint data on consumption, income, and assets of representative US households, I document the excess smoothness of consumption as an essential factor for portfolio choice and show that it can explain household finance puzzles. Furthermore, I formalized the effect of the excess smoothness on the portfolio choice using a structural life-cycle model where a household faces an idiosyncratic wage income risk. The model is calibrated to match relevant aspects of the dynamics and the life cycle of risky asset holding from the PSID. The second chapter assesses banks’ risk-shifting in the non regulated banking activity, also called shadow banking. Exploiting variations in risks disclosed by banks in their financial reports and using textual analysis tools, this document provides a new measure non regulated banking activity. The paper empirically documents that (1) banks are more likely to shift risk out of the regulator’s reach when their risk-based capital constraints become binding, (2) there is a positive relationship between risk-shifting and tail risk of banks. The paper then rationalizes banks’ risk-shifting behavior using a macroeconomic model with a financial sector. In the model, the event of default on debt and the presence of externality due to imperfect regulation enforcement encourage banks to engage in risk-shifting strategies. As a result, banks behave as cross-sector arbitrageurs. Finally, the paper uses this framework to study optimal regulation. We show that a tax on sectoral activity effectively reduces banks’ risk-shifting compared to other bank’s equity regulation policies. Finally, the third chapter studies the effect of carbon risk on economic stability using a consumption-based carbon emissions approach for 50 U.S. states over the years 1998 - 2018. The paper assumes a cross-sectional dependence from unobserved common factors (e.g., trade linkage, financial integration) between the states. Under this assumption, we find that one unit decreases in carbon emissions is associated with 4.5 percentage points decrease in the per capita output growth over the long run. Besides, we find differential impacts across the distribution of per capita states income. These findings inform the debate over the optimal transition path toward a low carbon economy.