Apesar de representarem apenas 1% das rochas expostas na superfície da Terra, as rochas alcalinas possuem um grande espectro composicional e são associadas a vários ambientes tectônicos terrestres. Além disso, seu estudo nos ajuda a compreender melhor a evolução térmica e geodinâmica do planeta. Potássio, sódio e cálcio são os principais elementos utilizados na classificação deste grupo de rochas, e as razões entre estes elementos nos dão pistas sobre sua origem. Este estudo experimental utilizou uma prensa hidráulica de 1000 tonf, com câmaras de perfil toroidal acopladas, para estudar o sistema kalsilita-nefelina-diopsídio-sílica anidro, a 4,0GPa (aprox. 120 km de profundidade) e temperaturas até 1400 °C, com foco nos planos lucita-nefelina-diopsídio (Lct-Nph-Di) e kalsilita-nefelina-diopsídio (Kls-Nph-Di). Os produtos dos experimentos foram analisados através de MEV-EDS e DRX Para o plano Lct-Nph-Di foram encontrados campos de estabilidade para os minerais kalsilita (Klsss), nefelina (Nphss), e clinopiroxênios (Cpxss) (ambos soluções sólidas), wollastonita e sanidina, além de três pontos invariantes: (A) Kls+Nph+Di+liquido (Lc62Ne29Di9) a 1000°C (pseudoeutético); (B) Kls+Sa+(Di+Wo)+liquido (Lct75Nph22Di2) a 1200°C (pseudoperitético), (C) Kls+Di+Wo+liquido (Lct74Nph17Di9) a 1000°C (pseudoeutético). O campo da kalsilita forma uma barreira termal entre os campos composicionais potássico/ultrapotássico e sódico do diagrama. No plano Kls-Nph-Di foram encontrados campos de estabilidade para Klsss, Nphss e Cpxss e duas fases aluminosas (espinélio e coríndon), além do ponto invariante Kls+Nph+Di(±Spl)+liquido (Kls47Nph43Di10) a 1100°C (pseudoeutético). Nossos dados sugerem que a 4,0 GPa a dissolução de K em Nphss é estendida para até 39% molar, e de Na em Klsss para até 27% molar, e que tal solução sólida parcial determina o quão ricos em K ou Na os líquidos gerados pelo sistema serão. Adicionalmente, nossos dados mostram correlaçãos entre concentrações álcalis e sílicas nos líquidos gerados: positiva para K2O, negativa para CaO, mas irregular para Na2O (este devendo depender de outros fatores). / The alkaline rocks represent only 1% of the exposed rocks on the Earth’s surface. Despite that, these rocks are a group with a wide compositional spectrum, associated to many tectonic contexts, and their study can help us to better understand the thermal and geodynamic evolution of our planet. Potassium, sodium and calcium are the main elements used in the classification of this group of rocks, and their concentration can give us insights about the origin of these rocks. We have experimentally investigated the Kalsilite–Nepheline–Diopside-Silica system at high pressure and temperature conditions (HPHT), with emphasis on silica-undersaturated volume (Leucite–Nepheline–Diopside and Kalsilite–Nepheline–Diopside planes), both at 4.0GPa (~120km deep) and dry conditions and temperatures up to 1400°C, aiming to better understand the influence of K2O, Na2O, and CaO in alkaline silica-undersaturated magmas. For the experiments, we used a 1000 tonf hydraulic press with toroidal chambers, and the run products were analyzed by XRD and SEM-EDS technique. In the Lct-Nph-Di plane we determined the stability fields for kalsilite (Klsss), nepheline (Nphss) and clinopyroxene solid solution (CPxss), wollastonite (Wo) and sanidine (Sa); and three piercing points: (A) Kls+Nph+Di+liquid (Lc62Ne29Di9) at 1000°C; (B) Kls+Sa+(Di+Wo)+liquid (Lct75Nph22Di2) at 1200°C, (C) Kls+Di+Wo+liquid (Lct74Nph17Di9) at 1000°C Kalsilite stability field represents a boundary between ultrapotassic/potassic vs. sodic compositions. In the plane Kls-Nph-Di, we found the stability fields for Klsss, Nphss and CPxss and two aluminous phases spinel (Spl) and corundum (Crn). This plane have a piercing point in Kls+Nph+Di(±Spl)+liquid (Kls47Nph43Di10) at 1100°C. Our data suggest that pressure extends K dissolution in Nph (up to 39%) and Na in Kls (up to 27%), and that these solid solutions determine eutectic positions in surrounding systems, or how much K-rich will be the generated magmas. Additionally, our data shows positive correlation between K2O and SiO2 concentration in magmas, negative correlation between CaO and SiO2 and no evident correlation with Na2O.

Apesar de representarem apenas 1% das rochas expostas na superfície da Terra, as rochas alcalinas possuem um grande espectro composicional e são associadas a vários ambientes tectônicos terrestres. Além disso, seu estudo nos ajuda a compreender melhor a evolução térmica e geodinâmica do planeta. Potássio, sódio e cálcio são os principais elementos utilizados na classificação deste grupo de rochas, e as razões entre estes elementos nos dão pistas sobre sua origem. Este estudo experimental utilizou uma prensa hidráulica de 1000 tonf, com câmaras de perfil toroidal acopladas, para estudar o sistema kalsilita-nefelina-diopsídio-sílica anidro, a 4,0GPa (aprox. 120 km de profundidade) e temperaturas até 1400 °C, com foco nos planos lucita-nefelina-diopsídio (Lct-Nph-Di) e kalsilita-nefelina-diopsídio (Kls-Nph-Di). Os produtos dos experimentos foram analisados através de MEV-EDS e DRX Para o plano Lct-Nph-Di foram encontrados campos de estabilidade para os minerais kalsilita (Klsss), nefelina (Nphss), e clinopiroxênios (Cpxss) (ambos soluções sólidas), wollastonita e sanidina, além de três pontos invariantes: (A) Kls+Nph+Di+liquido (Lc62Ne29Di9) a 1000°C (pseudoeutético); (B) Kls+Sa+(Di+Wo)+liquido (Lct75Nph22Di2) a 1200°C (pseudoperitético), (C) Kls+Di+Wo+liquido (Lct74Nph17Di9) a 1000°C (pseudoeutético). O campo da kalsilita forma uma barreira termal entre os campos composicionais potássico/ultrapotássico e sódico do diagrama. No plano Kls-Nph-Di foram encontrados campos de estabilidade para Klsss, Nphss e Cpxss e duas fases aluminosas (espinélio e coríndon), além do ponto invariante Kls+Nph+Di(±Spl)+liquido (Kls47Nph43Di10) a 1100°C (pseudoeutético). Nossos dados sugerem que a 4,0 GPa a dissolução de K em Nphss é estendida para até 39% molar, e de Na em Klsss para até 27% molar, e que tal solução sólida parcial determina o quão ricos em K ou Na os líquidos gerados pelo sistema serão. Adicionalmente, nossos dados mostram correlaçãos entre concentrações álcalis e sílicas nos líquidos gerados: positiva para K2O, negativa para CaO, mas irregular para Na2O (este devendo depender de outros fatores). / The alkaline rocks represent only 1% of the exposed rocks on the Earth’s surface. Despite that, these rocks are a group with a wide compositional spectrum, associated to many tectonic contexts, and their study can help us to better understand the thermal and geodynamic evolution of our planet. Potassium, sodium and calcium are the main elements used in the classification of this group of rocks, and their concentration can give us insights about the origin of these rocks. We have experimentally investigated the Kalsilite–Nepheline–Diopside-Silica system at high pressure and temperature conditions (HPHT), with emphasis on silica-undersaturated volume (Leucite–Nepheline–Diopside and Kalsilite–Nepheline–Diopside planes), both at 4.0GPa (~120km deep) and dry conditions and temperatures up to 1400°C, aiming to better understand the influence of K2O, Na2O, and CaO in alkaline silica-undersaturated magmas. For the experiments, we used a 1000 tonf hydraulic press with toroidal chambers, and the run products were analyzed by XRD and SEM-EDS technique. In the Lct-Nph-Di plane we determined the stability fields for kalsilite (Klsss), nepheline (Nphss) and clinopyroxene solid solution (CPxss), wollastonite (Wo) and sanidine (Sa); and three piercing points: (A) Kls+Nph+Di+liquid (Lc62Ne29Di9) at 1000°C; (B) Kls+Sa+(Di+Wo)+liquid (Lct75Nph22Di2) at 1200°C, (C) Kls+Di+Wo+liquid (Lct74Nph17Di9) at 1000°C Kalsilite stability field represents a boundary between ultrapotassic/potassic vs. sodic compositions. In the plane Kls-Nph-Di, we found the stability fields for Klsss, Nphss and CPxss and two aluminous phases spinel (Spl) and corundum (Crn). This plane have a piercing point in Kls+Nph+Di(±Spl)+liquid (Kls47Nph43Di10) at 1100°C. Our data suggest that pressure extends K dissolution in Nph (up to 39%) and Na in Kls (up to 27%), and that these solid solutions determine eutectic positions in surrounding systems, or how much K-rich will be the generated magmas. Additionally, our data shows positive correlation between K2O and SiO2 concentration in magmas, negative correlation between CaO and SiO2 and no evident correlation with Na2O.

Apesar de representarem apenas 1% das rochas expostas na superfície da Terra, as rochas alcalinas possuem um grande espectro composicional e são associadas a vários ambientes tectônicos terrestres. Além disso, seu estudo nos ajuda a compreender melhor a evolução térmica e geodinâmica do planeta. Potássio, sódio e cálcio são os principais elementos utilizados na classificação deste grupo de rochas, e as razões entre estes elementos nos dão pistas sobre sua origem. Este estudo experimental utilizou uma prensa hidráulica de 1000 tonf, com câmaras de perfil toroidal acopladas, para estudar o sistema kalsilita-nefelina-diopsídio-sílica anidro, a 4,0GPa (aprox. 120 km de profundidade) e temperaturas até 1400 °C, com foco nos planos lucita-nefelina-diopsídio (Lct-Nph-Di) e kalsilita-nefelina-diopsídio (Kls-Nph-Di). Os produtos dos experimentos foram analisados através de MEV-EDS e DRX Para o plano Lct-Nph-Di foram encontrados campos de estabilidade para os minerais kalsilita (Klsss), nefelina (Nphss), e clinopiroxênios (Cpxss) (ambos soluções sólidas), wollastonita e sanidina, além de três pontos invariantes: (A) Kls+Nph+Di+liquido (Lc62Ne29Di9) a 1000°C (pseudoeutético); (B) Kls+Sa+(Di+Wo)+liquido (Lct75Nph22Di2) a 1200°C (pseudoperitético), (C) Kls+Di+Wo+liquido (Lct74Nph17Di9) a 1000°C (pseudoeutético). O campo da kalsilita forma uma barreira termal entre os campos composicionais potássico/ultrapotássico e sódico do diagrama. No plano Kls-Nph-Di foram encontrados campos de estabilidade para Klsss, Nphss e Cpxss e duas fases aluminosas (espinélio e coríndon), além do ponto invariante Kls+Nph+Di(±Spl)+liquido (Kls47Nph43Di10) a 1100°C (pseudoeutético). Nossos dados sugerem que a 4,0 GPa a dissolução de K em Nphss é estendida para até 39% molar, e de Na em Klsss para até 27% molar, e que tal solução sólida parcial determina o quão ricos em K ou Na os líquidos gerados pelo sistema serão. Adicionalmente, nossos dados mostram correlaçãos entre concentrações álcalis e sílicas nos líquidos gerados: positiva para K2O, negativa para CaO, mas irregular para Na2O (este devendo depender de outros fatores). / The alkaline rocks represent only 1% of the exposed rocks on the Earth’s surface. Despite that, these rocks are a group with a wide compositional spectrum, associated to many tectonic contexts, and their study can help us to better understand the thermal and geodynamic evolution of our planet. Potassium, sodium and calcium are the main elements used in the classification of this group of rocks, and their concentration can give us insights about the origin of these rocks. We have experimentally investigated the Kalsilite–Nepheline–Diopside-Silica system at high pressure and temperature conditions (HPHT), with emphasis on silica-undersaturated volume (Leucite–Nepheline–Diopside and Kalsilite–Nepheline–Diopside planes), both at 4.0GPa (~120km deep) and dry conditions and temperatures up to 1400°C, aiming to better understand the influence of K2O, Na2O, and CaO in alkaline silica-undersaturated magmas. For the experiments, we used a 1000 tonf hydraulic press with toroidal chambers, and the run products were analyzed by XRD and SEM-EDS technique. In the Lct-Nph-Di plane we determined the stability fields for kalsilite (Klsss), nepheline (Nphss) and clinopyroxene solid solution (CPxss), wollastonite (Wo) and sanidine (Sa); and three piercing points: (A) Kls+Nph+Di+liquid (Lc62Ne29Di9) at 1000°C; (B) Kls+Sa+(Di+Wo)+liquid (Lct75Nph22Di2) at 1200°C, (C) Kls+Di+Wo+liquid (Lct74Nph17Di9) at 1000°C Kalsilite stability field represents a boundary between ultrapotassic/potassic vs. sodic compositions. In the plane Kls-Nph-Di, we found the stability fields for Klsss, Nphss and CPxss and two aluminous phases spinel (Spl) and corundum (Crn). This plane have a piercing point in Kls+Nph+Di(±Spl)+liquid (Kls47Nph43Di10) at 1100°C. Our data suggest that pressure extends K dissolution in Nph (up to 39%) and Na in Kls (up to 27%), and that these solid solutions determine eutectic positions in surrounding systems, or how much K-rich will be the generated magmas. Additionally, our data shows positive correlation between K2O and SiO2 concentration in magmas, negative correlation between CaO and SiO2 and no evident correlation with Na2O.

Les chondres, sphérules infra-millimétriques composées de minéraux silicatés de haute température, sont les constituants majeurs des météorites primitives. Ils présentent d'importantes variabilités texturales et chimiques révélatrices d'une histoire complexe. Cette thèse s'est intéressée à la chronologie de formation des chondres et de leurs précurseurs à deux échelles de temps distinctes aux moyens de deux approches complémentaires : la géochimie isotopique via le chronomètre isotopique à courte période ²⁶lAl-²⁶Mg et la pétrologie expérimentale. Le développement au cours de cette thèse d'un protocole analytique innovant de mesure in situ de haute précision par sonde ionique des compositions isotopiques du Mg et Al, a permis de démontrer l'homogénéité de la distribution de l'²⁶Al dans le disque d'accrétion, ce qui présente d'importantes implications sur la chronologie relative et les processus de formation des chondres, mais aussi sur l'origine de l'²⁶Al dans le Système Solaire. L'application de ce protocole analytique aux olivines reliques des chondres permet de préciser leur origine, ainsi que leur chronologie et leur processus de formation. Les expérimentations permettent de montrer qu'il est aisé de former des analogues de chondres de type II PO à partir de chondres de type I PO. Un tel processus de formation des chondres implique l'application de régimes thermiques isothermes suivis d'une trempe rapide, incompatibles avec les mécanismes classiques d'ondes de choc. D'autre part, nous montrons que les compositions chimiques en éléments majeurs et traces des différents types de chondres porphyriques peuvent être reproduites par le mélange de trois phases réfractaires solides héritées des précurseurs des chondres (olivine réfractaire, liquide réfractaire et métal) et d'une phase gazeuse riche en éléments volatils et modérément volatils. Ces résultats nous ont conduit à proposer un modèle de filiation entre les chondres / Chondrules are the major constituent of primitive meteorites. The large variability of textures and chemical compositions within chondrules is indicative of a complex history. This work is focused on the chronology of formation of chondrules and of their precursors by using two complementary tools: the short-lived radio-isotopes ²⁶Al-²⁶Mg and the experimental petrology.The development of a high precision analytical methodology for in situ measurements of the Mg and Al isotopic compositions by ion probe allows to demonstrate that the distribution of ²⁶Al was homogeneous within the accretion disk. This result has important implications for the chronology and process of chondrule formation and also for the origin of ²⁶Al in the Solar System. By using the same methodology with relict olivines in chondrules, we were able to constrain their origin and their formation process.From experimental petrology studies, we show that it was easy to form type II PO chondrules analogues from type I PO analogues. Such a process for chondrules formation implies an isothermal heating followed by a quick quench which is incompatible with the classical shock-waves model. Moreover, we show that the chemical compositions for major and trace elements of the different types of porphyritic chondrules can be easily reproduced by a mixing model composed of three refractory phases inherited from chondrules precursors (refractory olivine, refractory liquid and iron metal) and a gas phase enriched in volatile and moderately volatile elements. Finally, we propose a model of genetic linkage between the different types of porphyritic chondrules

The focus of this work is magma-crust interaction processes and associated crustal volatile release in subduction zone volcanoes, drawing on rock, mineral, and gas geochemistry as well as experimental petrology. Understanding the multitude of differentiation processes that modify an original magma during ascent to the surface is vital to unravel the contributions of the various sources that contribute to the final magmas erupted at volcanoes. In particular, magma-crust interaction (MCI) processes have been investigated at a variety of scales, from a local scale in the Vesuvius, Merapi, and Kelut studies, to a regional scale, in the Java to Bali segment of the Sunda Arc.  The role of crustal influences is still not well constrained in subduction systems, particulary in terms of the compositional impact of direct magma crust interplay. To address this shortcoming, we studied marble and calc-silicate (skarn) xenoliths, and used high resolution short timescale experimental petrology at Vesuvius volcano. The marbles and calc-silicates help to identify different mechanisms of magma-carbonate and magma-xenolith interaction, and the subsequent effects of volatile release on potential eruptive behaviour, while sequential short-duration experiments simulate the actual processes of carbonate assimilation employing natural materials and controlled magmatic conditions. The experiments highlight the efficiency of carbonate assimilation and associated carbonate-derived CO2 liberated over short timescales. The findings at Merapi and Kelut demonstrate a complex magmatic plumbing system underneath these volcanoes with magma residing at different depths, spanning from the mantle-crust boundary to the upper crust. The erupted products and volcanic gas emissions enable us to shed light on MCI-processes and associated volatile release in these systems. The knowledge gained from studying individual volcanoes (e.g., Merapi and Kelut) is then tested on a regional scale and applied to the entire Java and Bali arc segment. An attempt is presented to distinguish the extent of source versus crustal influences and establish a quantitative model of late stage crustal influence in this arc segment. This thesis therefore hopes to contribute to our knowledge of magma genesis and magma-crust interaction (MCI) processes that likely operate in subduction zone systems worldwide.

This work focuses on crustal interaction in magmatic systems, drawing on experimental petrology and elemental and isotope geochemistry. Various magma-chamber processes such as magma-mixing, fractional crystallisation and magma-crust interaction are explored throughout the papers comprising the thesis. Emphasis is placed on gaining insights into the extent of crustal contamination in ocean island magmas from the Canary Islands and the processes of magma-crust interaction observed both in nature and in experiments. This research underscores that the compositions of ocean island magmas, even primitive types which are classically used as probes of the mantle, are susceptible to modification by crustal contamination. The principal mechanisms of contamination identified from work on both Tenerife and Gran Canaria (Canary Islands) are assimilation and partial melting of the pre-existing island edifice and intercalated sediments by newly arriving magma (i.e. “island recycling”). The information that we can gain from studying solidified magma and entrained crustal xenoliths concerning the rates and mechanisms of crustal assimilation is, however, limited. To address this shortcoming, a series of time-variable crustal carbonate assimilation experiments were carried out at magmatic pressure and temperature using natural materials from Merapi volcano, Indonesia. A temporally constrained reaction series of carbonate assimilation in magma has hence been constructed. The experiments were analysed using in-situ techniques to observe the progressive textural, elemental, and isotopic evolution of magma-carbonate interaction. Crucially, carbonate assimilation was found to liberate voluminous crustally-derived CO2 on a timescale of only seconds to minutes in the experiments. This points to the role of rapid crustal degassing in volcanic volatile budgets, and, pertinently, in magnifying hazardous volcanic behaviour. This thesis, therefore, delivers detailed insights into the processes of magma-crust interaction from experiments and geochemistry. The outcomes confirm that crustal processes are significant factors in both, i) ocean island magma genesis, and ii) magma differentiation towards compositions with greater explosive potential which can, in turn, manifest as hazardous volcanism. / Felaktigt tryckt som Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 707