The latest Eocene and Oligocene was a time of marked paleoenvironmental change in Taranaki Basin, involving a transition from the accumulation of coal measures and inner shelf deposits to the development of upper bathyal environments. Up until the end of the Early Oligocene (Lower Whaingaroan Stage) Taranaki Basin had an extensional tectonic setting. Marine transgression culminated in the accumulation of condensed facies of the Matapo Sandstone Member of the lower part of the Ngatoro Group. During the Late Oligocene (Upper Whaingaroan Stage) Taranaki Basin's tectonic setting changed to one of crustal shortening with basement overthrusting westward into the basin on Taranaki Fault. The major part of the Ngatoro Group in thickness, including the Tariki Sandstone Member, Otaraoa Formation, Tikorangi Formation and Taimana Formation, accumulated in response to this change in tectonic setting. Various methods of stratigraphic and sedimentological characterisation have been undertaken to evaluate the stratigraphy of the Ngatoro Group. Wireline log records have been calibrated through particle sizing and carbonate digestion of well cuttings. A suite of wireline motifs have been defined for formations and members of the Ngatoro Group. The integration with other lithological and paleoenvironmental data sources has helped to better define the Late Eocene - Oligocene stratigraphy and sedimentary facies for eastern Taranaki Basin margin. U-Pb geochronology by laser ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS) has been used to determine detrital ages for over 350 zircons from 13 samples of Late Eocene - Oligocene sandstone samples in eastern Taranaki Basin and correlative onshore North Island units. The spread of ages (1554 - 102 Ma) and the proportion of ages in particular age bands integrated with modal petrography data have aided provenance evaluation. A range of source rocks contributed to the Late Eocene - Oligocene sedimentary units analysed, mainly the Waipapa Terrane (Early Permian to Late Jurassic) as shown by 206Pb/238U zircon ages and the abundance of fine-grained sedimentary rock fragments observed in samples. The Median Batholith (i.e. Darran/Median Suite and Separation Point Suite) is also identified as a significant source, indicated by Early Triassic to Early Jurassic and Early Cretaceous 206Pb/238U zircon ages and an abundance of quartz in samples. Other minor sources identified include Murihiku and Caples Terranes, Rakaia Sub-terrane and possibly the Karamea Batholith. The Tariki Sandstone and the Hauturu Sandstone have the same source, with the main 206Pb/238U zircon ages of aggregated samples (124 - 116 Ma and 121 Ma, respectively) consistent with a Separation Point Suite/Median Batholith (124 - 116 Ma) source. Derivation of sediments from a landmass that existed to the east and southeast of the Wellington area has been inferred for the Late Eocene - Oligocene units, with subsequent migration of sediments northward into Taranaki Basin and the Waikato Region (i.e. Te Kuiti Group depocentre) via longshore drift. New provenance data have been used to revise understanding about the development of eastern Taranaki Basin margin through the Late Eocene to earliest Miocene. Three new paleogeography maps are presented for the Runangan (Late Eocene), Lower Whaingaroan (Early Oligocene) and Upper Whaingaroan (early-mid-Oligocene). New paleogeography interpretations illustrate a dramatic change in the basin development between Matapo Sandstone (Lower Whaingaroan) and Tariki Sandstone (Upper Whaingaroan) deposition, consistent with an Upper Whaingaroan age for the start of reverse movement on Taranaki Fault.

Das Phänomen der Subduktion eines aktiven Spreizungszentrums an der Südspitze Südamerikas ist seit langem bekannt. Eine Vielzahl von geologischen Beobachtungen wurden mit diesem Phänomen in Verbindung gebracht, trotzdem ist der genaue Mechanismus der Beeinflussung des aktiven Kontinentalrandes weitgehend unbekannt. <br /> <br /> Die Zusammenhänge zwischen den Subduktionsprozessen und der Entwicklung der patagonischen Anden zwischen 47&#176;S und 48&#176;S stehen im Mittelpunkt der Untersuchungen. Um eine detaillierte zeitliche Auflösung der zugrunde liegenden Prozesse untersuchen zu können, wurde die Entwicklung der Vorlandsedimentation, die thermische Entwicklung und die Heraushebung der Oberkruste des andinen Orogens untersucht und diese in Bezug zur Subduktion des Chile-Rückens gesetzt. <br /> <br /> Im Bereich von 47&#176;30&prime;S wurden die synorogenen Vorlandsedimente der Santa Cruz Formation sedimentologisch untersucht. Diese fluviatilen Sedimente wurden in einem reliefarmen Vorlandgebiet durch häufige Rinnenverlagerung und dem Aufbau von Rinnenumlagerungsgürteln in Kombination mit assoziierten großräumigen Überflutungsablagerungen akkumuliert. Sie stehen in einem engen Zusammenhang mit der orogenen Entwicklung im andinen Liefergebiet. Dies spiegelt sich in dem nach oben gröber werdenden Zyklus der Santa Cruz Formation wider. Die magnetostratigraphischen Untersuchungen einer 270 m mächtigen Sequenz aus der Basis der Santa Cruz Formation, die mit 329 Einzelproben aus 96 Probenpunkten beprobt wurde, ergab 7 Umkehrungen der geomagnetischen Feldrichtung. Mit Hilfe der geomagnetischen Polaritätszeitskala (CANDE AND KENT, 1995) konnte der untersuchte Abschnitt der Santa Cruz Formation zwischen 16.2 und 18.5 Ma datiert werden. Als Träger der Sedimentations-Remanenz konnten überwiegend Pseudoeinbereichs-Magentitpartikel und untergeordnet Hämatitpartikel identifiziert werden. <br /> <br /> An drei Profilen der Santa Cruz Formation wurden aus Sandsteinlagen unterschiedlicher stratigraphischer Position detritische Apatite mit Hilfe der thermochronologischen Spaltspurmethode untersucht. Die thermisch nicht rückgesetzten, detritischen Apatite spiegeln das Auftreten unterschiedlicher Altersdomänen im Liefergebiet der Sedimente wider. In der Kombination mit den geochemischen Gesamtgesteinsuntersuchungen der Sedimente und den petrographischen Untersuchungen der Sandsteine, die ein überwiegend andesitisch-vulkanisch geprägtes Liefergebiet widerspiegeln, kann nachgewiesen werden, dass die Erosion im Liefergebiet um 16.5 Ma in tiefere, deformierte Krustensegmente einschneidet. Dies bedeutet, dass aufgrund der Denudation im andinen Orogen erste Sockelgesteinseinheiten in den Bereich der Abtragung gelangen und dass dieser Eintrag um 12 bis 10 Ma ein Volumen einnimmt, das zu signifikanten Änderungen der Gesamtgesteinsgeochemie der Vorlandsedimente führt. <br /> <br /> Die thermochronologische Untersuchung von Apatiten aus rezenten topographischen Höhenprofilen aus der Kernzone der patagonischen Anden im Bereich von 47&#176;30&prime;S zeigen den Beginn einer beschleunigten Heraushebung des Orogens um 7.5 Ma. Aus diesen Untersuchungen kann eine Denudationsrate im Zeitraum der letzen 7 bis 8 Ma von 600 bis 650 m/Ma abgeschätzt werden. Die Modellierung der Apatit-Spaltspurergebnisse zeigt eine signifikante Temperaturerhöhung im Zeitraum zwischen 12 und 8 Ma um 20 bis 30&#176;C für diesen Krustenbereich, die mit der Subduktion des aktiven Chile-Rückens in diesem Bereich der Anden in Verbindung gebracht wird. <br /> <br /> Aus den gewonnen Daten kann ein Modell für die Entwicklung der patagonischen Anden seit dem frühen Miozän abgeleitet werden. In diesem Modell wird die orogene Entwicklung in den patagonischen Anden auf eine erhöhte Konvergenzrate zwischen der Nazca Platte und der Südamerikanischen Platte zurückgeführt, die für die Heraushebung und Denudation der Anden sowie für die damit verbundene Entwicklung im Vorlandbereich verantwortlich ist. Diese orogene Entwicklung wird in einer späten Phase durch die nordwärts wandernde Subduktion des aktiven Spreizungszentrums des Chile Rückens überprägt und beeinflusst. Das auf der Integration von geologischen, chronologischen sowie thermochronologischen Daten beruhende Modell kann zahlreiche geologische und geophysikalische Beobachtungen in diesem Bereich der südlichen Anden konsistent erklären. / The phenomenon of active ridge subduction to the continental margin of southern South America has been well known for a long time. A diversity of geological observations are related to this phenomenon, however, the exact mechanism of the influence of ridge subduction to the active continental margin is unknown.<br /> <br /> The aim of the present investigations is to determine connections between the subduction processes and the development of the Patagonian Andes between 47&#176;S and 48&#176;S. In order to reach that objective, the development of the foreland basin settings, the uplift of the upper crust of the Andean Orogeny, and the relation with the subduction of the Chile Ridge were investigated to obtain a detailed temporal resolution of the basic geological processes.<br /> <br /> Within the area of 47&#176;30'S the style and sedimentological pattern of the synorogenic foreland deposits of the Santa Cruz Formation were investigated. These fluvial sediments were accumulated in a foreland basin of small scale topography by frequent progradational avulsions, which were accompanied by deposition of avulsion-belt sediments associated with thick overbank deposits. <br /> <br /> The upward-coarsening is best explained by progradation of fan deposits during an eastwards advancement of the deformation in the western Andes at that time. <br /> <br /> Magnetostratigraphic investigations of a total of 329 drill cores, which were collected at 96 sites, show seven major reversals in a thick stratigraphic section of 270 m from the base of the Santa Cruz Formation. A comparison with the geomagnetic polarity timescale of Cande and Kent (1995) gives a sedimentation age between 16.2 and 18.5 Ma for the investigated section of the Santa Cruz Formation. The investigation of rock-magnetism predominantly indicates magnetite and subordinated haematite as the dominant carrier of remanence. All results from hysteresis data determination cluster in the coarse pseudo-single (PSD) to multi-domain (MD) grain size range of the Day Diagram (DAY ET AL. 1977)<br /> <br /> Fission track analysis was applied to detrital apatite of sandstone samples at different stratigraphic positions within three sections of the Santa Cruz Formation. The fission track ages of the not reseted detrital apatite are assumed to be related to the age of the sediment provenance area. In combination with sandstone petrographic investigations, which indicate a dominant andesitic volcanic source for the sediment and geochemical whole rock investigations can be shown, that the erosion cuts into the basement of the source area at 16.5 Ma. This means, that due to the denudation in the Andean Orogen first deformed basement units arrive into the sedimentation cycle. In the range of 12 to 10 Ma this sediment input attained such a volume, that the whole-rock geochemistry of the sediments was changed .<br /> <br /> The thermochronological investigations of apatites from vertical profiles covering the largest elevation range of the central zone of the Patagonian Andes within the range of 47&#176;30'S show the beginning of an accelerated cooling and related uplift phase of the orogen at approximately 7.5 Ma. The calculated denudation rate in the period of the last 7 to 8 Ma ranges from 600 to 650 m/Ma. The modelling of apatite fission-track data shows a significant reheating in the range of 20 to 30&#176;C between 12 and 8 Ma for the upper crust. This is interpreted as an influence of the active Chile rise mid-oceanic spreading center on the overriding plate.<br /> <br /> The modelling of the apatite fission-track results shows a significant rise in temperature between 12 and 8 Ma around 20 to 30&#176;C for this crust area, which is associated with the subduction of the active Chile back in this area of the Andes. <br /> <br /> A model has been derived from the obtained data to explain the evolution of the Patagonian Andes since the early Miocene. In this model, orogeny is attributed to the increasing convergence rate between the Nazca plate and South America and its response due to uplift and denudation of the Patagonian Andes and the development of the adjacent foreland basin. In a late phase, orogeny is influenced and overprinted by the northward migration of the Chile ridge subduction. The model consistently explains many of the geological and geophysical observations.

Understanding spatial and temporal variations in strain accumulation and release along plate boundaries is a fundamental problem in tectonics. Short-term and long-term slip rates are expected to be equal if the regional stress field remains unchanged over time, yet discrepancies between modern geodetic (decadal time scale) slip rates and long-term geologic (10^3 to 10^6 years) slip rates have been observed on parts of the Pacific-North American plate boundary system. Contemporary geodetic slip rates are observed to be ~2 times greater than late Pleistocene geologic slip rates across the southern Walker Lane. I use a combination of GPS geodesy, detailed field geologic mapping, high-resolution LiDAR geodetic imaging, and terrestrial cosmogenic nuclide geochronology to investigate the observed discrepancy between long- and short-term slip rates. I find that the present day slip rate derived from GPS geodesy across the Walker Lane at ~37.5°N is 10.6 ± 0.5 mm/yr. GPS data suggest that much of the observed discrepancy occurs west of the White Mountains fault zone. New dextral slip rates on the White Mountains fault zone of 1.1 ± 0.1 mm/yr since 755 ka, 1.9 +0.5/-0.4 mm/yr since 75-115 ka, 1.9 +0.5/-0.4 mm/yr since 38.4 ± 9.0 ka, and 1.8 +2.8/-0.7 mm/yr since 6.2 ± 3.8 ka are significantly faster than previous estimates and suggest that slip rates there have remained constant since the middle Pleistocene. On the Lone Mountain fault I calculate slip rates of 0.8 ± 0.1 mm/yr since 14.6 ± 1.0 ka and 0.7 ± 0.1 mm/yr since 8.0 ± 0.5 ka, which suggest that extension in the Silver Peak-Lone Mountain extensional complex has increased dramatically since the late Pleistocene.

The geology, petrology and geochemistry of Catface porphyry Cu (Mo-Au) deposit, located on the west coast of Vancouver Island are examined in detail. Detailed core logging and sampling was carried out to characterize the geometry and identity of different intrusive phases and alteration styles prevalent during the emplacement and formation of the deposit, as well as their geochemical affinity. Early- and late-stage potassic alteration is identified, as well as main-stage sodic-calcic and calcic-sodic alteration. Four distinct Paleogene intrusive phases vary from quartz diorite to granodiorite in composition. The rocks are broadly calc-alkaline, weakly peraluminous to moderately metaluminous, and have typical arc geochemical affinity. The timing of emplacement and mineralization is constrained by U-Pb and Re-Os geochronology at 40.4-41.4 Ma and 40.9 ±0.2 Ma, respectively. All four Paleogene Catface intrusive phases were emplaced close in time with a direct temporal correlation to mineralization. The chalcopyrite- and pyrite-bearing miarolitic cavities in the Halo Porphyry intrusive, combined with U-Pb and Re-Os dates suggest this intrusive phase is the most likely source of mineralizing fluids. The intrusions were emplaced at depths of less four kilometers in the crust, as evidenced by the presence of miarolitic cavities and confirmed through amphibole-plagioclase thermobarometry, which record conditions of 615–700 °C and <200 MPa. The lack of primary anhydrite and hematite, and the presence of pyrrhotite in the ore system indicate a reduced magmatic-hydrothermal event. The SO3 contents in apatites are <450 ppm, indicative of a degassed and/or sulphate-free (reduced) magma. The assemblage K-feldspar-quartz-biotite-ilmenite yields oxygen fugacities (fO2) which are 0.5 to 3.0 log units below the quartz-fayalite-magnetite (QFM) buffer at an assumed pressure of 300 MPa; orders of magnitude more reduced than typical porphyry deposits. Parental magmas to the Catface deposit were either derived from intrinsically-reduced mantle, or more typical oxidized arc magma that was subsequently reduced during ascent and emplacement. Further isotopic work is required to determine which process contributed to the reduction of these magmas in an arc setting. Nevertheless, recognition of reduced porphyry-related magmatism on west-central Vancouver Island is of similar age to that of North Fork (~36.8-38.9 Ma) deposit in Washington suggesting a consanguinity of reduced magmatism with the Paleogene Cascade arc. / Graduate

Les effondrements massifs de flancs sont des évènements destructeurs qui affectent tous les édifices volcaniques. Ces effondrements peuvent impliquer quelques dizaines, voire centaines de km3 de roche. Les volcans boucliers océaniques, bien que possédant de faibles pentes, sont également affectés par ces épisodes destructeurs, entraînant la formation de tsunamis. Dans le contexte de bouclier océanique, ces déstabilisations n’ont jamais été observées. Actuellement, seules des reliques sont présentes sur les îles volcaniques, avec la présence de cicatrices d’effondrements, de dépôts détritiques en mer ou de dépôts de tsunami sur les îles voisines. Les relations entre le magmatisme des volcans boucliers et les effondrements de flanc sont peu contraintes. Afin de mieux comprendre ces relations, deux effondrements de flanc de volcans boucliers océaniques ont été étudiés : l’effondrement de Monte Amarelo sur l’île de Fogo, dans l’archipel du Cap Vert, et l’effondrement de Güímar, situé sur la rift-zone Nord-Est de Tenerife, dans l’archipel des Canaries. Les deux archipels résultent de l’activité d’un panache mantellique sous la plaque africaine.Les produits volcaniques pré et post-effondrement de ces deux secteurs ont été étudiés d’un point de vue géochimique (majeurs, traces, isotopes Sr-Nd-Pb), pétrologique et géochronologique (K-Ar, Ar-Ar), de manière à identifier à la fois les sources et les processus magmatiques mis en jeu lors de leur formation. L’évolution temporelle des sources, ainsi que des processus magmatiques, a été reconstruite afin d’identifier d’éventuels liens avec l’effondrement de flanc étudié.Les résultats montrent que l’évolution du magmatisme de l’île de Fogo amène à la formation de zones superficielles de stockage, de complexes intrusifs et d’éruptions explosives conduisant à de nouvelles instabilités de l’édifice. Suite à l’effondrement, ces zones de stockage sont déstabilisées en quelques milliers d’années. Les processus magmatiques lithosphériques (assimilation, fusion partielle) sont également perturbés mais sur une période plus longue (plusieurs dizaines de milliers d’années). L’effondrement de Güímar ne montre aucun lien avec le magmatisme de l’île de Tenerife.La différence principale entre ces deux contextes est la localisation de la zone effondrée par rapport au système magmatique. En effet, l’effondrement de Güímar est situé en périphérie du système magmatique et ne montre aucun lien avec ce dernier ; à l’inverse l’effondrement du Monte Amarelo, situé à l’aplomb du système magmatique, se répercute rapidement sur ce système à faible profondeur, mais également à des profondeurs lithosphériques avec un délai plus long. / Massive flank collapses are destructive events that affect all volcanic edifices. They can take off huge volumes of rock, from tens to hundreds km3. Oceanic shield volcanoes are also affected by such events even if they have shallow slopes, thus, tsunamis could also be generated in this context. However, a shield volcano flank collapse has never been observed. Nowadays, only relics are visible, such as collapse scars, detritic deposit offshore or tsunami deposits on nearby islands. The relationships between collapse and magmatic history of oceanic shield volcanoes are poorly constrained. Two flank collapses are studied in this thesis, with the aim to better understand these relationships: the Monte Amarelo collapse, on Fogo Island (Cape Verde), and the Güímar collapse, located on North-East rift-zone of Tenerife (Canary Islands). Those archipelagos are the result of hot spot activity below the African plate. Geochemical (major and trace elements, and Sr-Nd-Pb isotopes), petrological and geochronological (K-Ar and Ar-Ar) analyses were carried out on volcanic samples as to identify the source and magmatic processes at stake during magma genesis. The temporal evolution of source and magmatic processes is reconstructed in order to track possible links with the flank collapse. The magmatic system of Fogo Island evolves through time, favouring the formation of superficial storage zones, intrusive complex and explosive eruptions prior to the collapse, which participate to the instability of the edifice. Following the Monte Amarelo collapse, shallow storage zones are destabilized within a few thousand years. Lithospheric magmatic processes (assimilation, partial melting) are also affected but on a longer timescale (tens of thousands years). The Güímar collapse shows no links with the magmatic evolution of Tenerife Island. The main difference between the two collapses is the location of the collapse area with respect to the plumbing system. Güímar collapse is located at the periphery of the plumbing system and show no link with the magmatic history. Contrariwise, the Monte Amarelo collapse is located directly above the plumbing system and influence rapidly the superficial plumbing system, and the deep plumbing system in the long term.

Este trabalho objetiva a caracterização petrológica, geoquímica, geocronológica e metamórfica das rochas ortoderivadas pertencentes ao Complexo Metamórfico Brusque em duas regiões: Itapema e Botuverá, Santa Catarina, Brasil. Dos litotipos, destacam-se as exposições de rochas metamáficas e metaultramáficas, ocorrentes em ambas regiões. Em Itapema também foram investigados corpos de leucogranitos peraluminosos e na região da cidade de Botuverá foram investigados diques de diabásio e lamprófiro espessartítico. A análise das condições de geração e das fontes dos eventos magmáticos responsáveis pela geração destas rochas foi fundamental para a caracterização e avaliação do significado tectônico destas unidades no CMB, que foram posicionadas durante os períodos pré, sin e pós colisionais de evolução deste. A foliação regional do complexo é representada por uma S2 de baixo ângulo na região de Itapema e por uma superfície de mais alto ângulo na região de Botuverá, basculada por atuação da fase D3. Dados de geotermometria Hb-Pl indicam que a foliação principal dos xistos máficos foi gerada em condições da transição entre as fácies xistos verdes e anfibolito inferior. O magmatismo pré-orogênico do Complexo Metamórfico Brusque é constituído por lentes de rochas máficas-ultramáficas, produtos do metamorfismo de basaltos, gabros, rochas cumuláticas relacionadas e sedimentos vulcanogênicos. Estas rochas possuem afinidade toleítica e um elevado teor de ETR leves e elementos LILE. A análise de razões de elementos incompatíveis, a disposição dos corpos ígneos intercalados aos metassedimentos e a ausência de crosta oceânica sugerem que foram posicionados em ambiente tipo intra-placa continental, síncronos a sedimentação da bacia. Os valores iniciais de εNd entre -2.96 e 5.05 das rochas metavulcânicas de Itapema e entre -0.14 e -6.97 das rochas de Botuverá indicam a participação de crosta paleoproterozóica na gênese destes magmas. Os valores em geral elevados de 87Sr/86Sr justificam o envolvimento da crosta continental, e os valores mais altos encontrados em Botuverá, destacam o maior envolvimento deste componente na região. O magmatismo sin tectônico está representado por corpos de leucogranitos peraluminosos que mostram posicionamento concordante com a foliação S2. Os parâmetros composicionais destas rochas caracterizados pelas baixas razões K2O/Na2O, CaO/Na2O e LaN/YbN, os baixos teores de Rb, Sr, Zr, Y, Yb e Lu, são consistentes com uma evolução associada com magmas gerados a partir da fusão parcial de rochas crustais de composição pelíticas ricas em quartzo, com participação restrita de processos de diferenciação. Na região de Botuverá a ocorrência de diques de lamprófiros e diabásios que cortam as unidades metamórficas indica que seu posicionamento é pós-colisional. Geoquimicamente possuem afinidade entre as séries toleítica e shonshonítica. O padrão de distribuição dos elementos traços e as razões Th/Yb e Ta/Yb indicam que a extração dos diabásios ocorreu a partir de uma fonte mantélica enriquecida, com presença de rutilo e granada no resíduo e fortemente contaminada por crosta. Estas características são semelhantes às encontradas em rochas vulcânicas básicas pós-colisionais no sul do Brasil. Os dispersos valores de єNd(618) para os termos básicos, variando entre -13.74 e +5.52 destacam a heterogeneidade da fonte e reforçam a importância do componente crustal na geração destas rochas. Foi obtida uma idade concordante de 618 ±8.7 Ma (LA-ICP-MS) pelo método U-Pb em zircão, balizando a idade dos primeiros processos magmáticos pós-colisionais da orogênese brasiliana para a região de Botuverá. / This work objective the characterization of the petrology, geochemistry, geochronology and metamorphism of ortoderivate rocks that belong to Brusque Metamorphic Complex BMC) in two regions: Itapema and Botuverá, Santa Catarina, Brazil. Within these, good expositions of mafic and metaultramafic rocks occur in both regions. In Itapema, bodies of peraluminous leucogranites were also investigated. Around Botuverá were investigated diabase dikes and lamprophyres. The analysis of the conditions of generation and sources of magmatic events responsible for the development of these rocks was essential for the characterization and assessment of the significance of these tectonic units in the BMC, and it were placed during the pre-, syn-and post-collisional period of it’s evolution. The regional foliation of the complex is represented by a low angle S2 surface in Itapema region and a higher angle foliation in the region of Botuverá, folded by actuation of the D3 event. Petrography and Hb-Pl geothermometry data indicate that the main foliation of the mafic schists was generated in conditions between the transition of greenschist and lower amphibolite facies. The pre-orogenic magmatism of the Brusque Metamorphic Complex consists of lenses of mafic-ultramafic, products from the metamorphism of basalts, gabbros, related cumulate rocks and volcanogenic sediments. These rocks have a tholeiitic affinity and high contents of LREE and LILE elements. The analysis of incompatible elements ratios, the position of igneous bodies intercalated with the metasediments and the absence of oceanic crust suggest that the basalts were placed in an intra-continental plate environment, synchronous with sedimentation of the basin. The initial εNd values between -2.96 and 5.05 for the metavolcanics of Itapema and between -0.14 and -6.97 for the rocks of Botuverá indicate the involvement of Paleoproterozoic crust on the genesis of these magmas. The generally high 87Sr/86Sr values justify the involvement of crust, and the highest values found in Botuverá, highlight the greater involvement of this component in the region. Syn tectonic magmatism is represented by bodies of peraluminous leucogranite showing emplacement concordant to S2 foliation. Compositional parameters of these rocks characterized by low ratios K2O/Na2O, CaO/Na2O and LaN / YbN, low levels of Rb, Sr, Zr, Y, Yb and Lu, are consistent with magmas generated from partial melting of pelitic rocks, with limited participation of differentiation processes. In the region of Botuverá the occurrence of diabase dykes and lamprophyres cutting the regional metamorphic units indicates that its position is post-collisional. Geochemically show affinity between the tholeiitic and shonshonitic series. The distribution pattern of trace elements and the Th/Yb for Ta/Yb ratios indicate that extraction of diabase occur from an enriched mantle source, with the presence of rutile and garnet in the residue and heavily contaminated by crust. These characteristics are similar to those found in rocks post-collisional basaltic volcanic in south Brazil. The scattered values of єNd (618) in basic terms, ranging between -13.74 and +5.52 highlight the heterogeneity of mantle supply and reinforce the importance of crustal component in the generation of these rocks. A concordant age of 618 ± 8.7 Ma by U-Pb (LA-ICP-MS) zircon method were obtained, marking a early magmatic processes of post-collisional Brasiliano orogeny in the region of Botuverá.

Este trabalho objetiva a caracterização petrológica, geoquímica, geocronológica e metamórfica das rochas ortoderivadas pertencentes ao Complexo Metamórfico Brusque em duas regiões: Itapema e Botuverá, Santa Catarina, Brasil. Dos litotipos, destacam-se as exposições de rochas metamáficas e metaultramáficas, ocorrentes em ambas regiões. Em Itapema também foram investigados corpos de leucogranitos peraluminosos e na região da cidade de Botuverá foram investigados diques de diabásio e lamprófiro espessartítico. A análise das condições de geração e das fontes dos eventos magmáticos responsáveis pela geração destas rochas foi fundamental para a caracterização e avaliação do significado tectônico destas unidades no CMB, que foram posicionadas durante os períodos pré, sin e pós colisionais de evolução deste. A foliação regional do complexo é representada por uma S2 de baixo ângulo na região de Itapema e por uma superfície de mais alto ângulo na região de Botuverá, basculada por atuação da fase D3. Dados de geotermometria Hb-Pl indicam que a foliação principal dos xistos máficos foi gerada em condições da transição entre as fácies xistos verdes e anfibolito inferior. O magmatismo pré-orogênico do Complexo Metamórfico Brusque é constituído por lentes de rochas máficas-ultramáficas, produtos do metamorfismo de basaltos, gabros, rochas cumuláticas relacionadas e sedimentos vulcanogênicos. Estas rochas possuem afinidade toleítica e um elevado teor de ETR leves e elementos LILE. A análise de razões de elementos incompatíveis, a disposição dos corpos ígneos intercalados aos metassedimentos e a ausência de crosta oceânica sugerem que foram posicionados em ambiente tipo intra-placa continental, síncronos a sedimentação da bacia. Os valores iniciais de εNd entre -2.96 e 5.05 das rochas metavulcânicas de Itapema e entre -0.14 e -6.97 das rochas de Botuverá indicam a participação de crosta paleoproterozóica na gênese destes magmas. Os valores em geral elevados de 87Sr/86Sr justificam o envolvimento da crosta continental, e os valores mais altos encontrados em Botuverá, destacam o maior envolvimento deste componente na região. O magmatismo sin tectônico está representado por corpos de leucogranitos peraluminosos que mostram posicionamento concordante com a foliação S2. Os parâmetros composicionais destas rochas caracterizados pelas baixas razões K2O/Na2O, CaO/Na2O e LaN/YbN, os baixos teores de Rb, Sr, Zr, Y, Yb e Lu, são consistentes com uma evolução associada com magmas gerados a partir da fusão parcial de rochas crustais de composição pelíticas ricas em quartzo, com participação restrita de processos de diferenciação. Na região de Botuverá a ocorrência de diques de lamprófiros e diabásios que cortam as unidades metamórficas indica que seu posicionamento é pós-colisional. Geoquimicamente possuem afinidade entre as séries toleítica e shonshonítica. O padrão de distribuição dos elementos traços e as razões Th/Yb e Ta/Yb indicam que a extração dos diabásios ocorreu a partir de uma fonte mantélica enriquecida, com presença de rutilo e granada no resíduo e fortemente contaminada por crosta. Estas características são semelhantes às encontradas em rochas vulcânicas básicas pós-colisionais no sul do Brasil. Os dispersos valores de єNd(618) para os termos básicos, variando entre -13.74 e +5.52 destacam a heterogeneidade da fonte e reforçam a importância do componente crustal na geração destas rochas. Foi obtida uma idade concordante de 618 ±8.7 Ma (LA-ICP-MS) pelo método U-Pb em zircão, balizando a idade dos primeiros processos magmáticos pós-colisionais da orogênese brasiliana para a região de Botuverá. / This work objective the characterization of the petrology, geochemistry, geochronology and metamorphism of ortoderivate rocks that belong to Brusque Metamorphic Complex BMC) in two regions: Itapema and Botuverá, Santa Catarina, Brazil. Within these, good expositions of mafic and metaultramafic rocks occur in both regions. In Itapema, bodies of peraluminous leucogranites were also investigated. Around Botuverá were investigated diabase dikes and lamprophyres. The analysis of the conditions of generation and sources of magmatic events responsible for the development of these rocks was essential for the characterization and assessment of the significance of these tectonic units in the BMC, and it were placed during the pre-, syn-and post-collisional period of it’s evolution. The regional foliation of the complex is represented by a low angle S2 surface in Itapema region and a higher angle foliation in the region of Botuverá, folded by actuation of the D3 event. Petrography and Hb-Pl geothermometry data indicate that the main foliation of the mafic schists was generated in conditions between the transition of greenschist and lower amphibolite facies. The pre-orogenic magmatism of the Brusque Metamorphic Complex consists of lenses of mafic-ultramafic, products from the metamorphism of basalts, gabbros, related cumulate rocks and volcanogenic sediments. These rocks have a tholeiitic affinity and high contents of LREE and LILE elements. The analysis of incompatible elements ratios, the position of igneous bodies intercalated with the metasediments and the absence of oceanic crust suggest that the basalts were placed in an intra-continental plate environment, synchronous with sedimentation of the basin. The initial εNd values between -2.96 and 5.05 for the metavolcanics of Itapema and between -0.14 and -6.97 for the rocks of Botuverá indicate the involvement of Paleoproterozoic crust on the genesis of these magmas. The generally high 87Sr/86Sr values justify the involvement of crust, and the highest values found in Botuverá, highlight the greater involvement of this component in the region. Syn tectonic magmatism is represented by bodies of peraluminous leucogranite showing emplacement concordant to S2 foliation. Compositional parameters of these rocks characterized by low ratios K2O/Na2O, CaO/Na2O and LaN / YbN, low levels of Rb, Sr, Zr, Y, Yb and Lu, are consistent with magmas generated from partial melting of pelitic rocks, with limited participation of differentiation processes. In the region of Botuverá the occurrence of diabase dykes and lamprophyres cutting the regional metamorphic units indicates that its position is post-collisional. Geochemically show affinity between the tholeiitic and shonshonitic series. The distribution pattern of trace elements and the Th/Yb for Ta/Yb ratios indicate that extraction of diabase occur from an enriched mantle source, with the presence of rutile and garnet in the residue and heavily contaminated by crust. These characteristics are similar to those found in rocks post-collisional basaltic volcanic in south Brazil. The scattered values of єNd (618) in basic terms, ranging between -13.74 and +5.52 highlight the heterogeneity of mantle supply and reinforce the importance of crustal component in the generation of these rocks. A concordant age of 618 ± 8.7 Ma by U-Pb (LA-ICP-MS) zircon method were obtained, marking a early magmatic processes of post-collisional Brasiliano orogeny in the region of Botuverá.

Este trabalho objetiva a caracterização petrológica, geoquímica, geocronológica e metamórfica das rochas ortoderivadas pertencentes ao Complexo Metamórfico Brusque em duas regiões: Itapema e Botuverá, Santa Catarina, Brasil. Dos litotipos, destacam-se as exposições de rochas metamáficas e metaultramáficas, ocorrentes em ambas regiões. Em Itapema também foram investigados corpos de leucogranitos peraluminosos e na região da cidade de Botuverá foram investigados diques de diabásio e lamprófiro espessartítico. A análise das condições de geração e das fontes dos eventos magmáticos responsáveis pela geração destas rochas foi fundamental para a caracterização e avaliação do significado tectônico destas unidades no CMB, que foram posicionadas durante os períodos pré, sin e pós colisionais de evolução deste. A foliação regional do complexo é representada por uma S2 de baixo ângulo na região de Itapema e por uma superfície de mais alto ângulo na região de Botuverá, basculada por atuação da fase D3. Dados de geotermometria Hb-Pl indicam que a foliação principal dos xistos máficos foi gerada em condições da transição entre as fácies xistos verdes e anfibolito inferior. O magmatismo pré-orogênico do Complexo Metamórfico Brusque é constituído por lentes de rochas máficas-ultramáficas, produtos do metamorfismo de basaltos, gabros, rochas cumuláticas relacionadas e sedimentos vulcanogênicos. Estas rochas possuem afinidade toleítica e um elevado teor de ETR leves e elementos LILE. A análise de razões de elementos incompatíveis, a disposição dos corpos ígneos intercalados aos metassedimentos e a ausência de crosta oceânica sugerem que foram posicionados em ambiente tipo intra-placa continental, síncronos a sedimentação da bacia. Os valores iniciais de εNd entre -2.96 e 5.05 das rochas metavulcânicas de Itapema e entre -0.14 e -6.97 das rochas de Botuverá indicam a participação de crosta paleoproterozóica na gênese destes magmas. Os valores em geral elevados de 87Sr/86Sr justificam o envolvimento da crosta continental, e os valores mais altos encontrados em Botuverá, destacam o maior envolvimento deste componente na região. O magmatismo sin tectônico está representado por corpos de leucogranitos peraluminosos que mostram posicionamento concordante com a foliação S2. Os parâmetros composicionais destas rochas caracterizados pelas baixas razões K2O/Na2O, CaO/Na2O e LaN/YbN, os baixos teores de Rb, Sr, Zr, Y, Yb e Lu, são consistentes com uma evolução associada com magmas gerados a partir da fusão parcial de rochas crustais de composição pelíticas ricas em quartzo, com participação restrita de processos de diferenciação. Na região de Botuverá a ocorrência de diques de lamprófiros e diabásios que cortam as unidades metamórficas indica que seu posicionamento é pós-colisional. Geoquimicamente possuem afinidade entre as séries toleítica e shonshonítica. O padrão de distribuição dos elementos traços e as razões Th/Yb e Ta/Yb indicam que a extração dos diabásios ocorreu a partir de uma fonte mantélica enriquecida, com presença de rutilo e granada no resíduo e fortemente contaminada por crosta. Estas características são semelhantes às encontradas em rochas vulcânicas básicas pós-colisionais no sul do Brasil. Os dispersos valores de єNd(618) para os termos básicos, variando entre -13.74 e +5.52 destacam a heterogeneidade da fonte e reforçam a importância do componente crustal na geração destas rochas. Foi obtida uma idade concordante de 618 ±8.7 Ma (LA-ICP-MS) pelo método U-Pb em zircão, balizando a idade dos primeiros processos magmáticos pós-colisionais da orogênese brasiliana para a região de Botuverá. / This work objective the characterization of the petrology, geochemistry, geochronology and metamorphism of ortoderivate rocks that belong to Brusque Metamorphic Complex BMC) in two regions: Itapema and Botuverá, Santa Catarina, Brazil. Within these, good expositions of mafic and metaultramafic rocks occur in both regions. In Itapema, bodies of peraluminous leucogranites were also investigated. Around Botuverá were investigated diabase dikes and lamprophyres. The analysis of the conditions of generation and sources of magmatic events responsible for the development of these rocks was essential for the characterization and assessment of the significance of these tectonic units in the BMC, and it were placed during the pre-, syn-and post-collisional period of it’s evolution. The regional foliation of the complex is represented by a low angle S2 surface in Itapema region and a higher angle foliation in the region of Botuverá, folded by actuation of the D3 event. Petrography and Hb-Pl geothermometry data indicate that the main foliation of the mafic schists was generated in conditions between the transition of greenschist and lower amphibolite facies. The pre-orogenic magmatism of the Brusque Metamorphic Complex consists of lenses of mafic-ultramafic, products from the metamorphism of basalts, gabbros, related cumulate rocks and volcanogenic sediments. These rocks have a tholeiitic affinity and high contents of LREE and LILE elements. The analysis of incompatible elements ratios, the position of igneous bodies intercalated with the metasediments and the absence of oceanic crust suggest that the basalts were placed in an intra-continental plate environment, synchronous with sedimentation of the basin. The initial εNd values between -2.96 and 5.05 for the metavolcanics of Itapema and between -0.14 and -6.97 for the rocks of Botuverá indicate the involvement of Paleoproterozoic crust on the genesis of these magmas. The generally high 87Sr/86Sr values justify the involvement of crust, and the highest values found in Botuverá, highlight the greater involvement of this component in the region. Syn tectonic magmatism is represented by bodies of peraluminous leucogranite showing emplacement concordant to S2 foliation. Compositional parameters of these rocks characterized by low ratios K2O/Na2O, CaO/Na2O and LaN / YbN, low levels of Rb, Sr, Zr, Y, Yb and Lu, are consistent with magmas generated from partial melting of pelitic rocks, with limited participation of differentiation processes. In the region of Botuverá the occurrence of diabase dykes and lamprophyres cutting the regional metamorphic units indicates that its position is post-collisional. Geochemically show affinity between the tholeiitic and shonshonitic series. The distribution pattern of trace elements and the Th/Yb for Ta/Yb ratios indicate that extraction of diabase occur from an enriched mantle source, with the presence of rutile and garnet in the residue and heavily contaminated by crust. These characteristics are similar to those found in rocks post-collisional basaltic volcanic in south Brazil. The scattered values of єNd (618) in basic terms, ranging between -13.74 and +5.52 highlight the heterogeneity of mantle supply and reinforce the importance of crustal component in the generation of these rocks. A concordant age of 618 ± 8.7 Ma by U-Pb (LA-ICP-MS) zircon method were obtained, marking a early magmatic processes of post-collisional Brasiliano orogeny in the region of Botuverá.

Orientadores: Lena Virginia Soares Monteiro , Roberto Perez Xavier / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Geociências / Made available in DSpace on 2018-08-15T15:13:25Z (GMT). No. of bitstreams: 1 Moreto_CarolinaPenteadoNatividade_M.pdf: 6364154 bytes, checksum: 08d26b0642844f0ebe0c97e4f6816d34 (MD5) Previous issue date: 2010 / Resumo: O depósito de óxido de ferro-cobre-ouro Bacaba, situado no Cinturão de Cisalhamento Itacaiúnas, Província Mineral de Carajás, representa um alvo satélite do depósito de classe mundial Sossego, e possivelmente também representa as porções distais e profundas do mesmo sistema hidrotermal. O depósito Bacaba localiza-se ao longo de uma zona de cisalhamento com direção WNW-ESE que define o contato entre o embasamento, representado pelo Complexo Xingu (ca. 3,0 Ga), e a unidade metavulcano-sedimentar do Supergrupo Itacaiúnas (ca. 2,76 Ga). As principais rochas hospedeiras do minério no depósito Bacaba são representadas pelo Granito Serra Dourada, Tonalito Bacaba e por corpos gabróicos, que foram intensamente afetados por alterações hidrotermais sódica (albita-escapolita), potássica, clorítica e hidrolítica. Os dados de U-Pb LA-ICP-MS em zircão de uma amostra com alteração sódica do Granito Serra Dourada forneceram a idade de 2858 ± 30 Ma (MSWD = 9,7). Três amostras do Tonalito Bacaba, sendo uma com alteração potássica e duas com alteração potássica e mineralização de Cu-Au, forneceram idades em 2997,2 ± 4,7 Ma (MSWD = 1,15), 2993,1 ± 7,1 Ma (MSWD = 1,1) e 3004,7 ± 7,8 Ma (MSWD = 2,1), respectivamente. As idades em 2,86 e ca. 3,0 Ga são interpretadas como idade de cristalização do Granito Serra Dourada e do Tonalito Bacaba, respectivamente. As estruturas internas e morfologia dos cristais de zircão de ambas as rochas, observadas em imagens de catodoluminescência e de elétrons retro-espalhados, confirmam a ocorrência de processos de recristalização, que pode ser relacionado com episódios de hidrotermalismo e/ou deformação/metamorfismo que ocorreram na Província Mineral de Carajás. Contudo, esse (s) evento (s) não pode (puderam) ser datado (s) devido à ausência de abertura total do sistema isotópico U-Pb e ausência de cristais de zircão de origem hidrotermal.O Granito Serra Dourada e o Tonalito Bacaba são as rochas graníticas mais antigas até então reconhecidas no Cinturão de Cisalhamento Itacaiúnas. A presença dessas rochas tão antigas implica na existência de um importante magmatismo anterior à instalação da Bacia de Carajás (Supergrupo Itacaiúnas), e em uma história evolutiva mais complexa para o Cinturão de Cisalhamento Itacaiúnas. As similaridades petrográficas e geocronológicas dessas intrusivas félsicas do depósito Bacaba com suítes de rochas graníticas e tonalíticas reconhecidas no Terreno Granito-Greenstone Rio Maria, porção sul da Província Mineral de Carajás, implica na ocorrência de um magmatismo de ca. 3,0 e 2,86 Ga mais amplo e extenso. O Granito Serra Dourada e o Tonalito Bacaba não poderiam ser responsáveis pelo estabelecimento do sistema magmático-hidrotermal associado com a gênese do depósito Bacaba. Isso seria improvável porque outros depósitos com características similares são hospedados por unidades metavulcano-sedimentares mais novas (2,76 Ga). Nesse contexto, os depósitos de óxido de ferro-cobre-ouro do setor sul do Cinturão de Cisalhamento Itacaiúnas devem ser controlados principalmente por importantes descontinuidades crustais, como a zona de cisalhamento regional com direção WNW-ESE, ao invés de serem associados com um litotipo particular. Esses resultados indicam alto potencial de ocorrência de depósitos de óxido de ferro-cobre-ouro nas rochas mesoarqueanas do embasamento sob a Bacia de Carajás, particularmente aquelas cortadas por zonas de cisalhamento neoarqueanas. / Abstract: The Bacaba iron oxide-copper-gold deposit, situated in the Itacaiúnas Shear Belt, Carajás Mineral Province (Brazil), represents a satellite prospect of the world-class Sossego deposit, and might also represent a distal and deeper portion of the same or related hydrothermal system. The Bacaba deposit is located along a WNW-ESE-striking shear zone that defines the contact of the basement represented by the Xingu Complex (ca. 3.0 Ga) and the metavolcanosedimentary Itacaiúnas Supergroup (ca. 2.76 Ga). The main host rocks at Bacaba deposit comprise the Serra Dourada Granite, the Bacaba Tonalite and croscutting gabbro, which were intensely affected by sodic (albite-scapolite), potassic, chloritic and hydrolytic hydrothermal alterations. The U-Pb LA-ICP-MS data for zircon from sodic altered sample of the Serra Dourada Granite yielded an 2858 ± 30 Ma (MSWD = 9.7) age. Three samples from the Bacaba Tonalite, including one with potassic alteration and two with potassic alteration and Cu-Au mineralization rendered the 2997.2 ± 4.7 Ma (MSWD = 1.15), 2993.1 ± 7.1 Ma (MSWD = 1.1) and 3004.7 ± 7.8 Ma (MSWD = 2.1) ages, respectively. The 2.86 and ca. 3.0 Ga ages are interpreted as the igneous crystallization of the Serra Dourada Granite and the Bacaba Tonalite, respectively. The internal structures and external morphologies of zircon crystal from both rocks, observed in cathodoluminescence and backscattered electron images, attested the occurrence of zircon recrystallization, which could be related to hydrothermalism and/or deformation/metamorphism episodes that took place in the Carajás Mineral Province. However, the disturbing event (s) could not be dated due to the absence of the total resetting of the U-Pb system and hydrothermal crystallization of zircon. The 2.86 Ga Serra Dourada Granite and the ca. 3.0 Ga Bacaba Tonalite are the oldest granitic rocks so far recognized in the Itacaiúnas Shear Belt. The presence of such old rocks implies in the existence of an important magmatism before the Carajás Basin (Itacaiúnas Supergroup) deposition, and in a more complex evolutionary history for the Itacaiúnas Shear Belt. The petrographical and geochronological similarities of these felsic intrusions with granitic and tonalitic rock suites recognized in the Rio Maria granite-greenstone terrane, southern part of the Carajás Mineral Province, implies in a more widespread ca. 3.0 and 2.86 Ga magmatism in the province. The Serra Dourada Granite and the Bacaba Tonalite are interpreted not to be responsible for the genesis of the Bacaba deposit. This is likely because the Sossego and other deposits interpreted as part of the same hydrothermal system are hosted by younger ca. 2.76 Ga metavolcano-sedimentary units. On this context, the iron oxide-copper-gold deposit in the southern sector of the Itacaiúnas Shear Belt could be mainly controlled by important crustal discontinuities, such as the WNW-ESEstriking regional shear zone, rather than be associated with a particular rock type. These results expand the potentiality of occurrence of iron oxide-copper-gold deposits for the Mesoarchean basement rocks underlying the Carajás Basin, particularly those crosscut by Neoarchean shear zones. / Mestrado / Geologia e Recursos Naturais / Mestre em Geociências

Made available in DSpace on 2015-04-22T21:58:46Z (GMT). No. of bitstreams: 1 Cristovao da Silva Valerio.pdf: 2741646 bytes, checksum: 5327b16a1cfaa6bbb8b1b48cad050ee1 (MD5) Previous issue date: 2006-04-18 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work presents the geological arrangement of an area of ~560km2, located at the southwestern this district, where aerial disposition, contact relationships, petrographic and geochemistry variations and the Pb-Pb zircon geochronology are characterized, allowing to comment about the possible sources and ages of those rocks, beyond to propose a geodynamic model for northern Ventuari-Tapajós Province. This study was developed in three stages: (1) bibliographical revision and interpretation of the remote sensing products LANDSAT 5/TM, JERS, DTM, and SAR/SIPAM; (2) geological mapping and sampling; and (3) preparation of the samples for petrographic analyses, whole-rock geochemistry, and Pb- Pb zircon geochronology. The studied area is represented from monzogranites to diorites of the Água Branca Intrusive Suite, vulcanites of the Iricoumé Group, alkali-granites of the Mapuera Intrusive Suite, biotite granite (rapakivi) of the São Gabriel batholite and Neoproterozoic sediments of the Prosperança Formation. Assemble that geological setting, the Canoas Anorthosite, mafic and felsic dikes, beyond cenozoic laterithic coverings. The geochemistry and Pb-Pb zircon geochronology evaluation individualized two rock groups formed in different magmatic events delimited by ca. 1.89 B.y. ago, in which were generated high-K calc-alkaline biotite (hornblende) granites of the Água Branca Intrusive Suite (1898±3, 1895±3 e 1890±2Ma) and post-collisional to within-plate rhyolites, andesites, ignimbrites, K-feldspar granites and rapakivi biotite granites grouped, respectively, in the Iricoumé Group (1883±4Ma), Mapuera Intrusive Suite and São Gabriel batholite (1889±2Ma). I-type Água Branca granitoids revealed weakly peraluminous to metaluminous characteristics, high content in Ba, Sr and Rb/Zr, from LREE to HREE moderately fractionated, sin-collisional tectonic setting. The value of 1936±6Ma was considered as the contamination age from host-rock zircon crystals and 2002±14Ma age, in single-zircon crystal, was interpreted as inherited Pb-component originating from the late-transamazonian source. Post-collisional to within-plate studied rocks demonstrated weakly peraluminous, sub-alkaline, high- to ultra-K characteristics, high levels of Nb, Rb, Ta, Zr, Y e K/Rb and LREE weakly to moderately fractionated in relation to HREE. Different magmatic series and intracratonic reactivation suggest a tectonic model for the northern Ventuari-Tapajós Province is subduction-related paleoplate oceanic in the Amazonian proto-craton. This model brings about the collage and construction final processes of the Ventuari-Tapajós Province. After, processes of continental crust relaxation, post-collisional uplift and associated-caldroncollapse regional tension has occurred (i.e. vulcanites and granitoids of the Iricoumé-São Gabriel magmatism, and Mapuera ultra-K granitegenesis). The granitoids and vulcanites of the study area are compared in this work to the Tapajós Gold Province rocks, in the southern of the Ventuari-Tapajós Province, based on geochemistry and Pb-Pb zircon geochronology data. Therefore, Água Branca, Iricoumé and Mapuera units are correlated respectively to Parauari Intrusive Suite, Moraes Almeida Formation (Iriri Group) and Maloquinha Intrusive Suite. / Este trabalho apresenta o arranjo geológico de uma área de cerca de 560km2, localizada na porção sudoeste deste município, onde são caracterizadas a disposição areal, relações de contato, variações petrográficas e geoquímicas e a geocronologia Pb-Pb dos principais litotipos identificados nessa região, permitindo assim arquitetar comentários sobre as possíveis fontes e idades dessas rochas e propor um modelo geodinâmico para a porção norte da Província Ventuari-Tapajós. Os métodos de trabalho foram divididos em três etapas: (1) revisão bibliográfica e interpretação dos produtos de sensores remotos LANDSAT 5/TM, JERS, MDT e SAR/SIPAM; (2) mapeamento geológico e coleta de amostras; e (3) preparação das amostras para análises petrográficas, geoquímicas em rocha total e a geocronologia Pb-Pb em zircão. A área estudada é representada por monzogranitos a dioritos da Suíte intrusiva Água Branca, vulcanitos do Grupo Iricoumé, álcali-granitos da Suíte Intrusiva Mapuera, biotita granito do batólito São Gabriel e sedimentos proterozóicos da Formação Prosperança. Completam esse quadro, o Anortosito Canoas , diques máficos e félsicos, além de coberturas lateríticas do Cenozóico. As avaliações petrográficas, geoquímicas e a geocronologia Pb-Pb em zircão permitiram individualizar dois grupos de rochas formados em diferentes eventos magmáticos delimitados há ~1,89Ga. O primeiro grupo, constituído por rochas da Suíte intrusiva Água Branca, exibe características metaluminosa à fracamente peraluminosa, subalcalina (calcialcalina), tipo-I de médio a alto-K, conteúdos comparativamente altos em Ba, Sr e Rb/Zr e moderado a forte fracionamento dos ETR leves em relação aos ETR pesados. As idades Pb-Pb de 1898±3, 1895±3 e 1890±2Ma foram interpretadas como idades de cristalização, enquanto, que o valor médio de 1936±6Ma foi considerado como a idade de cristais de zircão da rocha encaixante e a idade 2002±14Ma, interpretada como idade de cristalização de um único cristal de zircão oriundo de uma rocha fonte tardi-transamazônica. As rochas pós-colisionais a intraplaca do Grupo Iricoumé, Suíte Intrusiva Mapuera e do batólito São Gabriel revelam características fracamente peraluminosa, subalcalina à alcalina, tipo-A de alto-K à ultra-K, mostram um enriquecimento em K, Nb, Rb, Ta, Zr, Y e K/Rb e moderado a fraco fracionamento dos ETR leves em relação aos ETR pesados. A idade de 1883±4Ma do Grupo Iricoumé foi caracterizada como a idade de cristalização, enquanto, a idade de 1889±2Ma do batólito São Gabriel foi interpretada como a idade de mínima de cristalização. As distintas séries magmáticas, acompanhadas de processos de reativação intracratônicos, sugerem que o modelo tectônico da borda norte da bacia do Amazonas, Província Ventuari-Tapajós, está relacionado à subducção da paleoplaca oceânica sob à Província Amazônia Central (Tassinari & Macambira 2004), envolvendo os processos finais de colagem e construção da Província Ventuari-Tapajós, associados ao magmatismo Água Branca, seguido do relaxamento da crosta continental, soerguimento pós-colisional e tensão regional com componente transtensional que resultou no vulcanismo Iricoumé, alojamento do batólito São Gabriel e na granitogênese ultra-K Mapuera. As unidades Água Branca, Iricoumé e Mapuera podem ser correlacionadas, respectivamente, à Suíte Intrusiva Parauari, Formação Moraes Almeida (Grupo Iriri) e à Suíte Intrusiva Maloquinha. Apesar da pequena extensão areal, a área estudada mostra interessante diversidade petrográfica e geoquímica, por se tratar de uma zona de amalgamento crustal convergente e pela relativa similaridade com a Província Aurífera Tapajós.