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O corpo máfico-ultramáfico da Fazenda Campo do Meio, localizado no município de Marcionílio Souza, estado da Bahia, é caracterizado como um lopólito assimétrico com 1300x500m e orientação leste-oeste. Geotectonicamente está inserido no Cráton do São Francisco, mais precisamente no Bloco Jequié, intrudido entre as encaixantes granulíticas charnockíticas. Litologicamente, o corpo apresenta estratigrafia invertida, sendo constituído por peridotitos (dunito, harzburgito e lherzolito) piroxenitos (olivina-ortopiroxenito, olivina websterito, websterito, hornblenda piroxenito e piroxênio hornblendito) e na porção máfica por hornblenda gabronorito como único representante. Os litotipos ultramáficos apresentam graus variados de serpentinização, e, de forma subordinada, cloritização e talcificação. Entretanto, as texturas primárias não foram completamente obliteradas, preservando assim a natureza ígnea do corpo com paragênese primária. Essa paragênese é representada por forsterita/crisólito, espinélio (hercinita), enstatita, augita e magnésio-hbl. No litotipo máfico a deformação foi mais expressiva com paragênese metamórfica formada por magnésio-hbl, diopsídio e labradorita. Os diagramas binários de elementos maiores, traço e terras raras demonstram que apesar dos eventos pós-magmáticos que afetaram as rochas, não houve interferência significativa no quimismo original das rochas ultramáficas, as quais apresentam olivina e ortopiroxênio como as principais fases controladoras do fracionamento magmático. Por fim, a partir dos dados litoquímicos, o corpo é caracterizado com uma intrusão de natureza toleítica continental e afinidades com magmas komatiíticos. Os dados geotermobarométricos sugerem que a temperatura de cristalização do corpo foi de 1325 a 1704ºC e a temperatura de reequilíbrio metamórfico foi de 869ºC com pressão em torno de 4 a 4,5 kbar, compatível com os dados bibliográficos de pressão para as rochas encaixantes granulíticas.

The Macau Volcanic Field (MVF) in the Borborema Province, NE Brazil, contains multiple centres of volcanic activity of Early to Late Cenozoic ages. We present element and Sr–Nd–Pb isotope geochemical data for four of the few most prominent basalt types of this volcanic field: Serrote Preto-type, Serra Aguda-type, Pico do Cabugi-type and Serra Preta-type, in order to assess their magmatic history from source to crystallization and the evolution of the mantle beneath the Borborema Province. The basalts are basically sodic nephelinitic–basanitic–alkali olivine basalts enriched in LILE and in Nb–Ta. The Serra Preta, Cabugi and Serra Aguda types demonstrate compositions close to primitive characteristics with 10%

Crustal assimilation plus crystal fractionation processes of different basanite magma batches control the evolution of the Ponte Nova cretaceous alkaline mafic–ultramafic massif in SE Brazil. This massif is composed of several intrusions, the main ones with a cumulate character. Disequilibrium features in the early-crystallized phases (e.g., corrosion and sieve textures in cores of clinopyroxene crystals, spongy-cellular-textured plagioclase crystals, gulf corrosion texture in olivine crystals) and classical hybridization textures (e.g., blade biotite and acicular apatite crystals) provide strong evidence of open-system behavior. All samples are olivine- and nepheline-normative rocks with basic–ultrabasic and potassic characters and variable incompatible element enrichments. The wide ranges of whole-rock 87 Sr/ 86 Sr i and 143 Nd/ 144 Nd i ratios (0.70432–0.70641 and 0.512216–0.512555, respectively) are indicative of crustal contribution from the Precambrian basement host rocks. Plagioclase and apatite 87 Sr/ 86 Sr ratios (0.70422–0.70927) obtained for the most primitive samples of each intrusion indicate disequilibrium conditions from early- to principal-crystallization stages. Isotope mixing-model curves between the least contaminated alkaline basic magma and heterogeneous local crustal components indicate that each intrusion of the massif is differentiated from the others by varied degrees of crustal contribution. The primary mechanisms of crustal contribution to the Ponte Nova massif involve the assimilation of host rock xenoliths during the development of the chamber environment and the assimilation of partial melts from the surrounding host rocks. Thermodynamic models using the melts algorithm indicate that parental alkaline basic magmas can be strongly affected by contamination processes subsequently to their initial stages of crystallization when there is sufficient energy to assimilate partial melts of crustal host rocks. The assimilation processes are considered to be responsible for the increse in the K 2 O/Na 2 O, Ba/Sr and Rb/Sr ratios. This enrichment was associated with the relevant role of biotite breakdown in the assimilated host rock partial melts. The petrological model for the Ponte Nova massif is explained as repeated influxes of antecryst-laden basanite magmas that deposited most of their suspended crystals on the floor of the upper-crust magma chamber. Each intrusion is representative of relatively primitive olivine- and clinopyroxene-phyric basanites that had assimilated different degrees of partial melts of heterogeneous host rocks. This study reveals the relevant role of crustal assimilation processes in the magmatic evolution of nepheline-normative rocks, especially in upper-crust chamber environments.

To obtain a classification of igneous rocks, compatible with the QAPF classification, in the absence of modal analyses, a chemical diagram using the same discriminating elements as the Q'(F')-ANOR normative diagram has been proposed. These elements, Si, Ca and K, are essential constituents of quartz, feldspars and feldspathoids. The different proportions between these minerals are the basis of the QAPF modal classification but also those of the normative classification Q'(F')-ANOR. The chemical diagram SiO2 100·CaO/(CaO+K2 O) uses these same elements but with the important difference that they are treated as independent variables. This characteristic allows igneous rocks to be classified with a nomenclature equivalent to that obtained by modal analyses, using only Si, Ca and K analytical data. The plotting of a set of representative plutonic and volcanic rocks reveals a remarkable concordance between both diagrams. However, some discrepancies and overlaps occur in the subsaturated fields due to the inability of the method to determine whether the lower silica content is due to the presence of olivine or feldspathoids. The samples selected belong to igneous series from diverse geotectonic areas , thus helping to evaluate the results in a global context Para obtener una clasificación de las rocas ígneas, compatible con la clasificación QAPF, cuando no se dispone de análisis modales se ha propuesto un diagrama químico que utiliza los mismos elementos discriminantes que el diagrama normativo Q'(F')-ANOR. Estos elementos, Si, Ca y K, son constituyentes esenciales del cuarzo, los feldespatos y los feldespatoides. Las diferentes proporciones entre estos minerales son la base de la clasificación modal QAPF pero también la de la clasificación normativa Q'(F')-ANOR. El diagrama químico SiO2100·CaO/(CaO+K2O) utiliza estos mismos elementos pero con la importante diferencia de que son tratados como variables independientes. Esta característica permite que puedan clasificarse las rocas ígneas con una nomenclatura equivalente a la obtenida mediante análisis modales disponiendo únicamente de los análisis de Si, Ca y K. La representación gráfica de un conjunto de rocas plutónicas y volcánicas representativas pone de manifiesto una concordancia notable entre ambos diagramas. No obstante, se producen algunas discrepancias y solapamientos en los campos subsaturados debido a la incapacidad del método para distinguir si el menor contenido en sílice se debe a la presencia de olivino o de feldespatoides. Las muestras escogidas pertenecen diversos ámbitos geotectónicos para poder valorar los resultados en un contexto global

To obtain a classification of igneous rocks, compatible with the QAPF classification, in the absence of modal analyses, a chemical diagram using the same discriminating elements as the Q'(F')-ANOR normative diagram has been proposed. These elements, Si, Ca and K, are essential constituents of quartz, feldspars and feldspathoids. The different proportions between these minerals are the basis of the QAPF modal classification but also those of the normative classification Q'(F')-ANOR. The chemical diagram SiO2 100·CaO/(CaO+K2 O) uses these same elements but with the important difference that they are treated as independent variables. This characteristic allows igneous rocks to be classified with a nomenclature equivalent to that obtained by modal analyses, using only Si, Ca and K analytical data. The plotting of a set of representative plutonic and volcanic rocks reveals a remarkable concordance between both diagrams. However, some discrepancies and overlaps occur in the subsaturated fields due to the inability of the method to determine whether the lower silica content is due to the presence of olivine or feldspathoids. The samples selected belong to igneous series from diverse geotectonic areas , thus helping to evaluate the results in a global context, Para obtener una clasificación de las rocas ígneas, compatible con la clasificación QAPF, cuando no se dispone de análisis modales se ha propuesto un diagrama químico que utiliza los mismos elementos discriminantes que el diagrama normativo Q'(F')-ANOR. Estos elementos, Si, Ca y K, son constituyentes esenciales del cuarzo, los feldespatos y los feldespatoides. Las diferentes proporciones entre estos minerales son la base de la clasificación modal QAPF pero también la de la clasificación normativa Q'(F')-ANOR. El diagrama químico SiO2100·CaO/(CaO+K2O) utiliza estos mismos elementos pero con la importante diferencia de que son tratados como variables independientes. Esta característica permite que puedan clasificarse las rocas ígneas con una nomenclatura equivalente a la obtenida mediante análisis modales disponiendo únicamente de los análisis de Si, Ca y K. La representación gráfica de un conjunto de rocas plutónicas y volcánicas representativas pone de manifiesto una concordancia notable entre ambos diagramas. No obstante, se producen algunas discrepancias y solapamientos en los campos subsaturados debido a la incapacidad del método para distinguir si el menor contenido en sílice se debe a la presencia de olivino o de feldespatoides. Las muestras escogidas pertenecen diversos ámbitos geotectónicos para poder valorar los resultados en un contexto global

Los magmas pueden dar origen a rocas plutónicas o volcánicas de la misma composición química. La composición modal de las rocas plutónicas puede ser cuantificada pero en el caso de las rocas volcánicas no suele ser posible por su textura afanítica y presencia de vidrio. Estas características impiden una clasificación mineralógica en diagramas equivalentes para ambos tipos de rocas. La IUGS recomienda el uso del diagrama químico TAS en los casos en que la obtención de la composición modal no sea posible, tratando de ajustar su nomenclatura a la del diagrama modal QAPF. Una mejor aproximación se consigue con el diagrama normativo Q'(F')-ANOR en el que se usa la relación anortita-ortosa como factor discriminante. En este trabajo se presenta el diagrama químico SiO2 -100·CaO/(CaO+K2 O) que reproduce en gran parte la clasificación normativa citada pero de forma simplificada, utilizando solamente tres componentes químicos discriminantes (SiO2 , CaO y K2 O). La delimitación y nomenclatura de los campos se ha realizado de forma empírica tomando como ejemplo el diagrama normativo y la representación de análisis de rocas ígneas características. El límite de saturación en sílice aproximado se ha dibujado como una recta que une las composiciones feldespáticas, comprendidas entre la ortosa y la anortita Magmas can form plutonic or volcanic rocks of the same chemical composition. The modal composition of the plutonic rocks can be quantified but in the case of volcanic rocks this is not always possible, because of its aphanitic texture and presence of glass. These characteristics prevent a mineralogical classification in equivalent diagrams for both types of rocks. To resolve this problem, the IUGS recommends the use of chemical TAS diagram in cases where obtaining the modal composition is not possible, in an attempt to adjust its nomenclature to that represented in the QAPF modal diagram. A best approximation is obtained with the normative diagram Q'(F')-ANOR in which the anorthite and the orthoclase are used as a discriminating factor. In this work, the chemical SiO2 -100·CaO/(CaO+K2 O) diagram is presented, which largely reproduces the aforementioned normative classification but in a simplified form since it uses only three discriminating chemical components (SiO2 , CaO and K2 O). The delimitation and nomenclature of the fields has been undertaken empirically using as an example the normative diagram and plotting the analyses of typical igneous rocks. The approximate limit of silica saturation has been drawn as a straight line joining the feldspathic compositions, between orthoclase and anorthite

The main aim of the present Ph.D. thesis is to improve our understanding of carbonation processes of serpentinized peridotite and the fate of serpentinite-hosted carbon during highpressure metamorphism, in order to better constrain their role in the deep carbon cycle of subduction zones. To advance in this overall research goal, this Ph.D. thesis presents the results of two natural case studies of key processes of carbon transfer during fluid-rock interaction in subduction zones: (i) listvenites from the Baie Verte ophiolite (Newfoundland, Canada), a natural analogue for carbon storage in the forearc mantle of subduction zones by carbonation of peridotites; and (ii) meta-ophicarbonates from the Nevado-Filábride Complex (Spain), which provide unprecedented insights into the stability of carbonates during antigorite-serpentinite dehydration in a paleo-subduction terrane. The combination of field, (micro) structural, petrological and geochemical data with thermodynamic modelling sheds new light on the interaction of fluids with the hydrated mantle, which regulates the carbon mobility at forearc and subarc depths of subduction zones. By means of thermodynamic models of prograde and high-pressure infiltration-driven devolatilization reactions in serpentinite-hosted meta-carbonate rocks, this thesis further investigates the effects of electrolytic fluids and the role of open-system flux by serpentinite dehydration fluids on the fluid-mediated release of carbon in subduction zones., [ES] El principal objetivo de la presente tesis doctoral es el de mejorar nuestra comprensión de los procesos de carbonatación de peridotitas serpentinizadas y el destino del carbono alojado en las serpentinitas durante el metamorfismo de alta presión; la finalidad ultima de este estudio es contribuir a un mejor entendimiento del papel que juegan estos procesos en el ciclo profundo del carbono en las zonas de subducción. Para avanzar en este objetivo general de investigación, en esta tesis se presentan los resultados de estudios de afloramientos naturales fósiles en los que se registran dos procesos clave de transferencia de carbono durante la interacción fluido-roca en zonas de subducción: (i) las listvenitas de la ofiolita de Baie Verte (Terranova, Canadá), que constituye un análogo natural del almacenamiento de carbono por carbonatación de peridotitas del manto de antearco de una zona de subducción; y (ii) los meta-oficarbonatos del complejo Nevado-Filábride (Cordillera Bética, España), que proporcionan información unica sobre la estabilidad de los carbonatos durante la deshidratación de serpentinitas con antigorita en un terreno metamórfico de paleosubducción. La combinación de datos de campo, (micro) estructurales, petrológicos y geoquímicos con modelos termodinámicos ha proporcionado una mejor comprensión de la interacción de los fluidos con el manto hidratado, que regula la movilidad del carbono en las profundidades del antearco y arco volcánico de las zonas de subducción. Mediante modelos termodinámicos de las reacciones de devolatilización en sistema cerrado y abierto, esta tesis investiga los efectos de los fluidos electrolíticos y el papel de los fluidos de deshidratación de serpentinita en la liberación de carbono en rocas carbonatadas en serpentinitas de la placa que subduce de las zonas de subducción., Thesis has been funded by the People Programme (Marie Curie Actions) of the European Union's Seventh Framework Programme FP7/2007- 2013/ under REA grant agreement n°608001, in the frame of the Marie-Curie Initial Training Network ABYSS; Funding from the Spanish “Agencia Estatal de Investigación” (AEI) under grants no. CGL2016–75224–R, CGL2016–81085–R, and grant nº PCIN–2015–053. The “Junta de Andalucía”; Funding of research groups under grants nº RNM–131, RNM–374, and P12–RNM–3141; This research and the research infrastructure at the IACT have benefitted from (co)funding from the European Social Fund and the European Regional Development Fund

Los magmas pueden dar origen a rocas plutónicas o volcánicas de la misma composición química. La composición modal de las rocas plutónicas puede ser cuantificada pero en el caso de las rocas volcánicas no suele ser posible por su textura afanítica y presencia de vidrio. Estas características impiden una clasificación mineralógica en diagramas equivalentes para ambos tipos de rocas. La IUGS recomienda el uso del diagrama químico TAS en los casos en que la obtención de la composición modal no sea posible, tratando de ajustar su nomenclatura a la del diagrama modal QAPF. Una mejor aproximación se consigue con el diagrama normativo Q'(F')-ANOR en el que se usa la relación anortita-ortosa como factor discriminante. En este trabajo se presenta el diagrama químico SiO2 -100·CaO/(CaO+K2 O) que reproduce en gran parte la clasificación normativa citada pero de forma simplificada, utilizando solamente tres componentes químicos discriminantes (SiO2 , CaO y K2 O). La delimitación y nomenclatura de los campos se ha realizado de forma empírica tomando como ejemplo el diagrama normativo y la representación de análisis de rocas ígneas características. El límite de saturación en sílice aproximado se ha dibujado como una recta que une las composiciones feldespáticas, comprendidas entre la ortosa y la anortita, Magmas can form plutonic or volcanic rocks of the same chemical composition. The modal composition of the plutonic rocks can be quantified but in the case of volcanic rocks this is not always possible, because of its aphanitic texture and presence of glass. These characteristics prevent a mineralogical classification in equivalent diagrams for both types of rocks. To resolve this problem, the IUGS recommends the use of chemical TAS diagram in cases where obtaining the modal composition is not possible, in an attempt to adjust its nomenclature to that represented in the QAPF modal diagram. A best approximation is obtained with the normative diagram Q'(F')-ANOR in which the anorthite and the orthoclase are used as a discriminating factor. In this work, the chemical SiO2 -100·CaO/(CaO+K2 O) diagram is presented, which largely reproduces the aforementioned normative classification but in a simplified form since it uses only three discriminating chemical components (SiO2 , CaO and K2 O). The delimitation and nomenclature of the fields has been undertaken empirically using as an example the normative diagram and plotting the analyses of typical igneous rocks. The approximate limit of silica saturation has been drawn as a straight line joining the feldspathic compositions, between orthoclase and anorthite

Las ofiolitas de Sierra de Baza corresponden a uno de los pocos afloramientos dentro de las ofiolitas Béticas aún sin estudiar como tal. Esta Asociación ofiolítas Bética forman parte del Complejo del Mulhacén, junto a la Unidad de la Caldera infrayacente y la Unidad de las Sabinas suprayacente. Constituyendo dos mantos de corrimiento, de origen cortical, compuestos por basamentos principalmente Paleozóicos y coberteras mesozocias. El Complejo del Veleta, formado por varios miles de metros de micaesquistos con grafito aflora como una serie de ventanas tectónicas bajo el Complejo del Mulhacén y constituyen las unidades más profundas de la Cordillera Bética. El manto ofiolítico está compuesto por rocas básicas, ultramáficas y sedimentarias, afectadas en parte por metamorfismo de fondo oceánico, que durante la Orogenia Alpina, se vieron afectadas por el metamorfismo orogénico polifásico. Las rocas ultramáficas son serpentinitas con clinopiroxeno y harzburgitas secundarias, que en muchos afloramientos de la asociación ofiolítica Bética, contienen diques basálticos parcialmente rodingitizados y metamorfizados. Todos los magmas que forman parte de estas ofiolitas, como diques, gabros y basaltos, son de procedencia astenosférica y su ambiente geodinámico de génesis corresponde al de una dorsal oceánica, de tipo E-MORB y fueron generados a lo largo de una zona de acreción de placas oceánicas. Algunos de estos magmas atravesaron localmente, en su salida a la superficie oceánica, materiales corticales, produciéndose una asimilación local de los mismos, dilucidable por algunos rasgos químicos de la roca total, que indican que el suelo oceánico del que derivan estas ofiolitas se originó por aumento de la distensión de la litosfera y corteza continental, y ascenso de la astenosfera a partir del Jurásico inferior, prolongandose episódicamente a lo largo del cretácico. Las etapas prejurásicas de rifting y adelgazamiento cortical, que afectaron a las unidades de la Caldera y de las Sabinas del Complejo del Mulhacén, fueron caracterizadas por el desarrollo de ortogneises piroclásticos Permo-Triásicos en ambas unidades (Puga et al., 1996; Nieto, 1997; Nieto et al., 2000), justo antes de la separación de las placas continentales adelgazadas y del inicio del magmatismo astenosférico, que originó el suelo oceánico del que deriva la Unidad Ofiolítica. Una sucesión de procesos geodinámicos y magmáticos similares a los mencionados, dieron lugar también al desarrollo de la dorsal Atlántica, en su zona central, de edad Pliensbaquiense, que coincide exactamente con el inicio del desarrollo del suelo oceánico bético (Puga et al., 2017). La datación geocronológica del inicio del magmatismo que originó el suelo oceánico del que procede la Asociación ofiolítica Bética, se ha llevado a cabo mediante dataciones U-Pb con SHRIMP de circones de metagabros y metabasaltos en diferentes afloramientos de la AOB. Estas dataciones indican que la ruptura de la corteza continental adelgazada para dar paso a la acreción del suelo oceánico bético, tuvo lugar en un lapso de tiempo corto, localizado entre el Pliesbaquiense y el Toarciense (187-177 M.a.). No obstante, este magmatismo astenosférico persistió como vulcanismo episódico, originando abundantes sills que se intercalaron a lo largo de la secuencia sedimentaria, depositada sobre este suelo oceánico, que ha sido datada, mediante microfósiles, como cretácica. Este episodio de vulcanismo cretácico está bien representado en numerosos afloramientos de ofiolitas Béticas a lo largo del Complejo del Mulhacén, incluyendo los afloramientos de Sierra de Baza (como puede verse en el capítulo 2: Marco geológico de las ofiolitas de Sierra de Baza). En la reconstrucción paleogeográfica del Mesozoico de la Cordillera Bética y del Tethys occidental Ligur y Alpino, del que proceden las ofiolitas alpino- apenínicas, la edad radiométrica indica la procedencia de estas últimas de un suelo oceánico generado unos 20 M.a. después del que formó el Océano Bético. Esto está en contradicción con lo previamente publicado por numerosos autores sobre la génesis y evolución del Tethys occidental, como consecuencia de la ruptura de la Pangea, que suponían que el Océano Bético se había generado posteriormente a los Océanos Ligur y Alpino., Tesis Univ. Granada.

The first precise ID-TIMS U–Pb baddeleyite/zircon dating of dykes representative of the main activity in the Florianopolis Dyke Swarm (Parana–Etendeka Magmatic Province, south Brazil) reveals a restricted age range (134.7 ± 0.3 to 133.9 ± 0.7 Ma). This is at least 5 Ma older than indicated by previous 40 Ar/ 39 Ar stepwise heating dating, and precludes a direct relationship with syn-rifting magmatism connected with opening the south Atlantic Ocean. Instead, as indicated by their age and geochemical signature, these dykes are feeders to the nearby Urubici lavas (and coeval Khumib lavas in Etendeka). These new geochronological results also cast doubt on a large (> 10 Ma) time span for the emplacement of the Florianopolis Dyke Swarm implied by 40 Ar/ 39 Ar dates, but the determination of its upper age limit still requires accurate dating of younger, low-volume fine-grained dykes with distinct low-Ti chemistry; crystals suitable to U–Pb dating were not obtained thus far from these dykes.

The Late Cretaceous Búzios Island alkaline massif intrudes Precambrian charnockites and consists dominantly of syenitic rocks that are cut by a large number of dikes, mostly NE-trending, and representing two distinct suites, a felsic one and a mafic-ultramafic one. Alkali feldspar is the most abundant mineral; other constituents are clinopyroxene, commonly replaced by amphibole/biotite, and opaques. Accessory minerals include occasionally rare phases bearing Zr, Ti, Nb and Rare Earth Elements (REE). The felsic dikes may also have nepheline (sodalite). The mafic-ultramafic suite, in particular the lamprophyres, shows a primary mineral assemblage with olivine, clinopyroxene and amphibole in addition to a groundmass having glassy material and carbonates (ocelli). The Búzios rocks are chemically evolved, mostly of potassic affinity and mainly belong to the miaskitic series. Variation diagrams for major and trace elements show a bimodal distribution, suggesting an origin from different magmatic pulses. The rocks are interpreted as having been derived by fractional crystallization processes from a basanitic parental magma. The SiO2-undersaturated and SiO2-oversaturated associations present in the massif are apparently not linked to a single magmatic source, and in the petrogeny residual system two trends are evident: the first one towards the phonolitic minimum and the second one towards the rhyolitic minimum, possibly pointing to amphibole fractionation. RESUMO: O maciço alcalino da Ilha dos Búzios, do Cretáceo Superior, é intrusivo em charnockitos precambrianos e consiste predominantemente de rochas sieníticas cortadas por grande número de diques, orientados preferencialmente para NE, representando duas suítes distintas: félsica e máfica-ultramáfica. Feldspato alcalino é o mineral mais abundante; outros constituintes são clinopiroxênio, comumente substituído por anfibólio/biotita, e opacos. Minerais acessórios incluem ocasionalmente fases raras contendo Zr, Ti, Nb e elementos terras raras (ETR). Os diques félsicos podem possuir também nefelina (sodalita). A suíte máfica-ultramáfica, particularmente os lamprófiros, apresenta uma assembleia mineralógica primária com olivina, clinopiroxênio e anfibólio, além de massa fundamental com material vítreo e carbonatos (ocelli). As rochas de Búzios são quimicamente evoluídas, de filiação claramente potássica e pertencem sobretudo à série miaskítica. Diagramas de variação para elementos maiores e traços mostram distribuição bimodal, sugerindo a origem a partir de diferentes pulsos magmáticos. As rochas são interpretadas como derivadas por cristalização fracionada a partir de magma parental de composição basanítica. As associações insaturadas e supersaturadas em SiO2 presentes no maciço não estão aparentemente ligadas a uma fonte magmática única, sendo evidentes duas tendências distintas no sistema petrogenético residual: a primeira no sentido do mínimo fonolítico, e a segunda no do mínimo riolítico, possivelmente indicando fracionamento de anfibólio.

The Monte de Trigo alkaline suite is a SiO2-undersaturated syenite-gabbroid association from the Serra do Mar alkaline province. Eudialyte-group minerals (EGMs) occur in one nepheline microsyenite dyke, associated with aegirine-augite, wöhlerite, låvenite, magnetite, zircon, titanite, britholite, and pyrochlore. Major compositional variations include Si (25.09- 25.57 apfu ), Nb (0.31- 0.76 apfu ), Fe (1.40-2.13 apfu ), and Mn (1.36- 2.08 apfu ). The EGMs also contain relatively high contents of Ca (6.13- 7.10 apfu ), moderate enrichment of rare earth elements (0.38-0.67 apfu ), and a relatively low Na content (11.02-12.28 apfu ), which can be correlated with their transitional agpaitic assemblage. EGM compositions indicate a complex solid solution that includes eudialyte, kentbrooksite, feklichevite, zirsilite-(Ce), georgbarsanovite, and manganoeudialyte components. EGM trace element analyses show low Sr and Ba contents and a negative Eu/Eu* anomaly, which are interpreted as characteristic of the parental magma due to the previous fractionation of plagioclase and/or alkali feldspar. The EGMs from the dyke border have higher contents of Fe, Sr (2,161-2,699 ppm), Mg (1,179-3,582 ppm), and Zn (732- 852 ppm) than those at the dyke center. These differences are related to the incorporation of xenoliths and xenocrysts of melatheralitic host rock into the nepheline-syenitic magma followed by crystal-melt diffusive exchange. RESUMO: A suíte alcalina do Monte de Trigo é uma associação sienítico-gabroide que pertence à província alcalina da Serra do Mar. Minerais do grupo da eudialita (EGMs) ocorrem em um dique de nefelina microssienito associados a egirina-augita, wöhlerita, lavenita, magnetita, zircão, titanita, britolita e pirocloro. As principais variações composicionais incluem Si (25,09-25,57 apfu ), Nb (0,31-0,76 apfu ), Fe (1,40-2,13 apfu ) e Mn (1,36-2,08 apfu ). Os EGMs também contêm concentrações relativamente altas de Ca (6,13-7,10 apfu ), enriquecimento moderado de elementos terras raras (0,38-0,67 apfu ) e concentrações relativamente baixas de Na (11,02-12,28 apfu ), o que pode ser correlacionado com uma assembleia agpaítica transicional. As composições dos EGMs indicam uma solução sólida complexa entre os componentes eudialita, kentbrooksita, feklichevita, zirsilita-(Ce), georgbarsanovita e manganoeudialita. Análises de elementos traços das EGMs mostram baixas concentrações de Sr e Ba e anomalia negativa de Eu/Eu*, que são interpretadas como uma característica do magma parental por conta do fracionamento de plagioclásio e/ou feldspato alcalino. Os EGMs da borda do dique possuem concentrações maiores de Fe, Sr (2.161-2.699 ppm), Mg (1.179-3.582 ppm) and Zn (732-852 ppm) que aqueles do centro do dique. Essas diferenças estão relacionadas com a incorporação de xenólitos e xenocristais da rocha encaixante melateralítica no magma nefelina-sienítico seguido de trocas difusivas entre os cristais e o líquido.

The Niquelândia Complex, Brazil, is one of the world's largest mafic–ultramafic plutonic complexes. Like the Mafic Complex of the Ivrea-Verbano Zone, it is affected by a pervasive high-T foliation and shows hypersolidus deformation structures, contains significant inclusions of country-rock paragneiss, and is subdivided into a Lower and an Upper Complex. In this paper, we present new SHRIMP U–Pb zircon ages that provide compelling evidence that the Upper and the Lower Niquelândia Complexes formed during the same igneous event at ca. 790 Ma. Coexistence of syn-magmatic and high-T subsolidus deformation structures indicates that both complexes grew incrementally as large crystal mush bodies which were continuously stretched while fed by pulses of fresh magma. Syn-magmatic recrystallization during this deformation resulted in textures and structures which, although appearing metamorphic, are not ascribable to post-magmatic metamorphic event(s), but are instead characteristic of the growth process in huge and deep mafic intrusions such as both the Niquelândia and Ivrea Complexes. Melting of incorporated country-rock paragneiss continued producing hybrid rocks during the last, vanishing stages of magmatic crystallization. This resulted in the formation of minor, late-stage hybrid rocks, whose presence obscures the record of the main processes of interaction between mantle magmas and crustal components, which may be active at the peak of the igneous events and lead to the generation of eruptible hybrid magmas.

[ES] En este trabajo se muestra la distribución espacial de las diferentes formaciones geológicas que forman los Complejos del Veleta y del Mulhacén en el en el Espacio Natural de Sierra Nevada y se ilustran, mediante fotos macroscópicas y microscópicas, sus tipos de rocas mas característicos. Los Complejos del Veleta y del Mulhacén, constituyen las unidades mas profundas de las Cordilleras Béticas y afloran en Sierra Nevada formando los picos de mayor altura de la Península Ibérica. El Complejo del Veleta (CV) está formado por varios miles de metros de micaesquistos con grafito y aflora como una serie de ventanas tectónicas bajo el Complejo del Mulhacén (CM). Este último complejo está formado por dos mantos de corrimiento, de origen cortical, compuestos por basamentos Paleozoicos y coberteras Mesozoicas, entre los cuales está tectonicamente intercalado un manto ofiolítico de edad Jurásico- Cretácica. Dentro de los mantos de origen cortical del CM se encuentran rocas meta-graníticas, generadas por un magmatismo sin-colisional tardi-hercínico y por un vulcanismo, ácido a intermedio, de carácter intraplaca post-colisional. El manto ofiolítico está compuesto por rocas básicas, ultramáficas y sedimentarias, afectadas por metamorfismo de fondo oceánico y por metamorfismo orogénico. Las rocas ultramáficas son serpentinitas y harzburgitas secundarias, que contienen diques basálticos parcialmente rodingitizados y metamorfizados. El metamorfismo alpino desarrolló en el CM facies de eclogitas a las que se superpusieron facies de anfibolitas de Ab-Ep, mientras que en el CV se desarrollaron facies de anfibolitas de Ab-Ep seguidas por facies de esquistos verdes. Las diferentes unidades tectónicas que forman los Complejos del Veleta y del Mulhacén, así como la Formación de Soportújar, que se depositó sobre materiales del CM en una etapa intraorogénica alpina, fueron definidas basándose en las características de algunos afloramientos que están muy bien representados dentro del Espacio Natural de Sierra Nevada. Estos afloramientos constituyen una serie de georrecursos petrológicos que son esenciales para reconstruir el origen y la evolución petrogenética de Sierra Nevada y, por extensión, de la Cordillera Bética. Por esta razón, requieren un grado máximo de preservación, que impida su destrucción y el expolio de las rocas y minerales que los integran., [EN] We show the spatial distribution of the various geological formations that make up the Veleta and Mulhacén Complexes into the Sierra Nevada Park and illustrate, with macro- and microscopic photographs, their most characteristic types of rock. The Veleta and Mulhacén Complexes were previously considered together as the Nevado-Filábride Complex. They constitute the deepest units of the Betic Cordilleras and crop out in Sierra Nevada forming the highest peaks of the Iberian Peninsula. The Veleta Complex (VC) is formed of several thousand metres of graphite-bearing micaschists and crops out as a series of tectonic windows below the Mulhacén Complex (MC). This latter complex comprises two thrust nappes of crustal origin, composed of a Palaeozoic basement and Mesozoic cover series, between which a Jurassic-Cretaceous ophiolitic nappe is tectonically intercalated. Within the MC nappes of crustal origin, there appear meta-granitic rocks, generated in a late-Hercynian syn-collisional magmatism and a Permian to Triassic, post-collisional intraplate, acidic-to-intermediate volcanism. The ophiolitic nappe is composed of basic, ultramafic and sedimentary rocks affected by ocean-floor and orogenic metamorphism. The basic rocks mainly retain their original MORB character. The ultramafic rocks are serpentinites and secondary harzburgites containing partly rodingitized meta-basaltic dykes. The Alpine metamorphism developed eclogite facies followed by Ab-Ep amphibolite facies in the MC and Ab-Ep amphibolite facies followed by greenschist facies in the VC. The different tectonic units forming the Veleta and Mulhacén Complexes, so as the Soportujar Formation, which was deposited over the MC units during an alpine intraorogenic stage, were defined from outcrops very well represented into the Natural Space of Sierra Nevada. These outcrops constitute a series of petrological georesources, which are essential to reconstruct the origin and petrogenetic evolution of Sierra Nevada and, by extension, of the Betic Cordillera. For this reason, they would deserve the highest degree of protection in order to prevent the destruction and plundering ot their rocks and minerals., Junta de Andalucía n.º RNM 333. MEC BTE 2003-09808

Se estudian macro y microscópicamente las rocas del Stock Granodioritico de Córdoba, localizadoen la Cordillera Central de Colombia, entre las poblaciones de Génova y Pijao, en el Departamento delQuindío y que aflora en su extremo meridional en las Quebradas La Maizena y Cristales en una extensiónde 3 km2 , al nororiente de la población de Génova. Al occidente de la zona de estudio afloran esquistosnegros del Grupo Bugalagrande, rocas ultramáficas serpentinizadas, esquistos anfibólicos y anfibolitaslocalmente granatíferas del Complejo Rosario, y las rocas del "Complejo Quebradagrande". El cuerpoígneo está compuesto de granodioritas que pueden variar hasta cuarzodioritas, contiene xenolitos deanfibolitas y diques de composición anclesítica. Todas estas rocas han sido sometidas a procesos tectónicosoriginando cataclasis. Las granodioritas fueron generadas en un evento magmático de edad CretáceoTardío que instruyó rocas del Complejo Rosario y del "Complejo Quebradagrande" con las cuales elintrusivo actualmente este en contacto fallado al occidente. Al sur oriente el contacto con las rocas del"Complejo Quebradagrande" es intrusivo. Los xenolitos de anfibolitas en el cuerpo ígneo hacen parte delas rocas del basamento metamórfico y fueron arrastradas por el magma félsico en el momento de laintrusión. La composición química de los elementos de la hornblenda de tres muestras de xenolitos deanfibolita, obtenida con microsonda EDAX, es semejante a la composición de la hornblenda en unaanfibolita granatífera obtenida del Complejo Rosario, lo cual indicaría que ambas se formaron durante elmismo evento metamórfico. De acuerdo a las observaciones de campo, las descripciones realizadas de27 secciones delgadas y en base al análisis de la composición química por medio de la microsonda, dela hornblenda de dos xenolitos de anfibolita, de una granodiorita y de una anfibolita granatífera, seencontró que la aparente complejidad del cuerpo intrusivo se debe a la existencia de numerosos xenolitosde anfibolita, y al no ser posible identificar un segundo evento magmático o la existencia de magmascompuestos en él, se propone el nombre de Stock Granodiorítico de Córdoba para describir el cuerpoígneo.

3 DIPARTIMENTO DI SCIENZE DELLA TERRA, UNIVERSITY OF TRIESTE, VIA E. WEISS 8, I-34127 TRIESTE, ITALY 4 INSTITUTO DE GEOCIENCIAS, UNIVERSIDADE DE SAO PAULO, C.P. 30627, 01051 SAO PAULO, SP, BRAZIL 5 DIPARTIMENTO DI SCIENZE DELLA TERRA, ‘LA SAPIENZA’ UNIVERSITY, PIAZZALE ALDO MORO 5, I-00185, ROME, ITALY 6 ISTITUTO DI MINERALOGIA, PETROGRAFIA E GEOCHIMICA, UNIVERSITY OF PALERMO, VIA ARCHIRAFI 36, I-90100

Tholeiitic basaltic and basaltic andesite dikes of Brasiliano (or PanAfrican) age (≈ 600 Ma) intrude the basement of the Nico Perez region, Uruguay. Major and trace element geochemistry of the basalts indicates that they suffered fractionation in shallow magma chambers. The variation in element ratios, which remain virtually unchanged during fractionation (K/Rb, Rb/Ba, Ba/Nb, La/Nb, Zr/Nb and Ti/Zr), indicate that the dikes are not strictly comagmatic. However, they have certain features in common: LILE and LREE enrichment with respect to HFSE and HREE; high Rb/Ba (> 0.9) and Rb/Sr (> 0.08); low K/Rb ( 2; Ba/Nb > 22 Ti/Zr < 60).87Sr/86Sr and143Nd/144Nd at 665 Ma are in the range 0.7052 – 0.7119 and 0.51158 – 0.51177, respectively.

A program for the calculation of several norms and of a large number of geochemical parameters and indexes is herein presented. NORMAS, a revised and updated version of already published programs, was written in Turbo-Basic and belongs to a package of computer programs which is being developed at the IG-USP.These programs can be linked to data banks and aim the treatment of geochemical data of rocks. NORMAS allows the calculation of not only the CIPW, the Catanorm and Alkalic Norm (either in weight percent or cationic form), but of a Mesonorm and an Epinorm as well. The calculated parameters and indexes are currently the most widely used by penologists and are derived from input values expressed in weight per cent of oxides, cationic and molecular proportions, and normative values. An additional and simple routine can display the input data (weight quantities of oxides and elements) and the calculated parameters and indexes as binary diagrams.

The nomenclature and classification of breccias of igneous origin has been, and still is, a subject of considerable debate, which reflects the ongoing discussions about their formation and emplacement. This is especially valid for those breccias emplaced in plutonic or subvolcanic environments. During field studies in the large alkaline massif of Pocos de Caldas, southern Brazil, the author was confronted by a seemingly bewildering variety of breccias and other pyroclastic rocks, thus providing the impetus for a revision of the subject and the proposal for simple ways of describing and classifying such breccias. Special emphasis was placed on the important group of breccias emplaced at depth ("subsurface breccias") which are notoriously difficult to catalogue and to interpret; subaqueous types are non-existent, or at least very rare, in Pocos de Caldas, and are not dealt with in the present discussion. Breccias should be clearly characterized borrowing terminology and methods from the field of study of fragmental supracrustal (epiclastic and pyroclastic) rocks, both for descriptive purposes (e.g., description of form, sorting, roundness, petrographic variety, etc.) as well as for size ranges; in addition, other textural terms, such as "clast-supported", "clast-matrix supported", and "matrix-supported", should be used to describe the clast-to-matrix relationship. A breccia of igneous origin is defined as a clastic rock with suitable amounts (>;25%) of (angular to rounded) fragments greater than 2 mm which originates as a direct response to igneous phenomena. Genetic aspects of breccia formation are not considered a satisfactory guideline for classification purposes, mostly because breccia-forming processes are still very poorly undeir stood. The mechanisms, which have been proposed in the literature, range from well- researched and qualified hypothesis (such as the "implosion-fluidization" model of Biondi, 1979) to highly unlikely speculations. Still lacking is the ability to take the guesswork out of interpretations of texture and structure of breccias. In the proposed classification, emphasis is placed on descriptive and geologic aspects, in order to define the geologic environment in which the breccia was emplaced. On the one hand, this procedure introduces a standard nomenclature, independent of any genetic meaning (or misconception); additionally, emphasis on detailed description of the geologic environment may ultimately lead to a sounder basis for interpretation. The simplest classification of breccias is therefore threefold, recognizing only "volcanic", " subvolcanic" and "plutonic breccias". The first group comprises all deposits related to volcanic supracrustal activity, including various types of autoclastic flow breccias (including rubble found on advancing block lavas, and talus deposits and collapse fragments shed during cooling and growth of subaerially exposed volcanic domes), tephra deposits, pyroclastic flows and epigenetic sheets formed as a direct response to volcanism (e.g., lahars). The second group, associated with subvolcanic phenomena, includes types found in small, more or less confined bodies (pipes, necks, dikes, sills, irregular bodies: "conduits" in the broadest sense). Among these are autoclastic (e.g.,"friction" breccias) and xenolithic varieties (fragments enclosed within a groundmass of non-fragmented volcanic rocks). The most significant types, the economically important conduit breccias associated with explosive activities, are subdivided, merely for descriptive purposes, into non-intrusive varieties ("shatter" breccias, with angular fragments; "cracked" or "craquelee" rock; collapse breccias, with fragments derived from nearby wall-rocks) and the clearly intrusive types (including both conduit breccias with more or less angular fragments, accompanied by varying but usually important amounts of matrix, and conduit agglomerates, with rounded fragments and little or no matrix). There has been wide speculation as to the proper generating mechanism, fluidization usually being advanced as the main emplacement cause (probably triggered by an initial "implosion"). In well-defined subvolcanic conduits, it is observed that shatter breccias, "cracked" rock, and conduit breccias are distributed in a roughly zoned pattern; the first two types are restricted to wall-rock areas and are probably formed as a response to explosion-related com pressions and decompressions, while the conduit breccias appear as centrally located bodies. The group of "plutonic breccias" are divided into border types (protoclastic and friction breccias marginal to plutons, which are, structurally, cataclasites or milonites), agmatites (fragments in a groundmass of plutonic rock), "metasomatic" substitution varieties, and plutonic conduit breccias (with features similar to those encountered in the equivalent subvolcanic types).