Late-stage fissure-filling ore at the world class Bingham Canyon, Utah, porphyry copper deposit has long been recognized, but poorly studied. Physical and chemical characterization of the Pb-Zn-Cu-Ag-Au mineralized fissures in the porphyry-epithermal transition zone provides insight into the origin, timing, and controls of ore deposition. These sheared sulfide-rich fissures are dominated by pyrite and multiple generations of quartz, with lesser amounts of other sulfides and gangue minerals. Au (0.27 to 4.61 ppm) provides the most value to the ore in the transition zone. Host rocks include Eocene monzonite and Paleozoic limestone and quartzite"”all of which can contain economic ore bodies. Associated alteration is predominantly sericitic and argillic. Mineralization into the wall rocks is restricted, not exceeding 1.5 m from the fissure margins. Mineral assemblages vary with distance from the center of the main Cu-Mo deposit and the modal abundances are dependent on host rock. The appearance of both galena and sphalerite (and tennantite to an extent) mark the transition from a porphyry to an epithermal environment. This is accompanied by an increased concentration of chalcophile trace elements in sulfides as determined by EMPA and LA-ICP-MS. Significant hosts of Ag include galena and tennantite, while Cu is hosted primarily in chalcopyrite, tennantite, and sphalerite. Gold does not appear to be hosted in solid solution, but may be focused along fractures or inclusions in pyrite. δ3434S values of fissure pyrite has a narrow range (+2.3 to 3.4‰), while δ18O of quartz is more variable and high (+11.5 to 14.0‰) relative to typical hydrothermal quartz. This can be explained by increased fractionation at lower temperatures in the magmatic fluids, which could have additionally mixed with exchanged 18O-rich meteoric water. Ore grades improve with distance from the center of the deposit; however, this is accompanied by higher concentrations of elements (Pb, As, Bi, etc.) undesirable for downstream processing. The mineralized fissures were created sequentially throughout the formation of the deposit. Initial joints probably formed as a result of the intrusion of a barren equigranular monzonite. The NE orientation of the joints was controlled by the regional stress field, which is more apparent distal to the center of the deposit. A quartz monzonite porphyry then intruded, dilating the joints to allow precipitation of quartz and then pyrite during the Cu-Au-stage of mineralization in the main ore body. After dike-like intrusions of latite porphyry and quartz latite porphyry intruded, galena, sphalerite, and pyrite precipitated to form the Pb-Zn-Ag mineralization. This was followed by late precipitation of chalcopyrite and tennantite (and likely Au mineralization).

Ammonium has been detected in and around several epithermal Au-Ag deposits, including those in Nevada, Japan, Argentina, Mexico, and New Zealand, using short-wave infrared (SWIR) reflectance spectroscopy. This study examined the distribution and occurrence of ammonium in three epithermal low-sulfidation vein-type deposits in the Hauraki goldfield of New Zealand: Martha (>6.7Moz Au, >42.1Moz Ag), Favona (>0.6Moz Au, >2.36Moz Ag), and the recently discovered Wharekirauponga (WKP; 0.42Moz Au, 0.8Moz Ag) deposit. The Martha and Favona auriferous quartz-adularia veins are hosted by late Miocene to Pliocene andesite, whereas auriferous veins at WKP are hosted by late Miocene to Pliocene rhyolite. The wallrock of all three deposits is altered to form quartz, illite, smectite, adularia, chlorite, and pyrite +/- kaolinite. Ammonium contents are enriched (>137 ppm) in wallrock samples from all three deposits and low (<94 ppm) in vein samples. Ammonium contents are higher at Favona (<10,675 ppm) than at Martha (<192 ppm) and WKP (<2,783 ppm). Leaching experiments using a 2N KCl solution show that most ammonium is in mineral structures (>90% at Favona, >80% at Martha, >70% at WKP). There is a positive correlation of ammonium contents with LOI (0.6 – 16.3 wt%) and with K2O (1.3 – 8.0 wt%) in all samples which suggest a hydrous potassium mineral as the major host of the ammonium. This is supported by the SWIR data obtained by previous workers of these samples where they show an absorption at ~1410 nm due to OH. At Favona, samples with high ammonium (>990 ppm) are reported to have significant absorption at ~2000 nm and ~2100 nm in the SWIR spectra likely due to ammonium. High ammonium contents (990 – 10,675 ppm) are found in rocks less than ~100m from the Favona vein which occur within an ammonium-bearing zone identified by previous workers based on SWIR. Samples outside of this zone contain low ammonium (107 – 301 ppm) with the smectite altered samples being the lowest. Ammonium contents within the hangingwall (1,827 – 10,675 ppm) of the Favona vein tend to be higher than in the footwall (990 – 4,301 ppm) and are highest within the most intensely illite altered rocks. At WKP, the intensely adularia +/- minor illite altered samples within 100m of the main East-Graben (EG) vein contain low ammonium (<200 ppm). The intensely illite altered samples away from the EG vein (>100m) have higher ammonium contents (200 – 800 ppm). This relationship of high ammonium contents to high illite abundance confirms illite as the major host of ammonium in these deposits. δ15N values for all samples (n=54) including near and far from auriferous veins range from +0.5 to +7.9 ‰, suggesting the derivation of most of the ammonium from the Jurassic greywacke basement or sediments intercalated within the volcanic rocks.

O evento sensu lato Uatumã é caraterizado pelo intenso magmatismo de afinidade cálcio-alcalina, relacionado com a presença de arcos vulcânicos continentais Paleoproterozóicos no período 2,1 a 1,88 Ga, associados com as suítes magmáticas Cuiú- Cuiú, Creporizão, Parauari, com significativa relevância no potencial metalogenético na porção sul do Cráton Amazônico, especificamente na Província Mineral do Tapajós. Inclui também as rochas vulcânicas alcalinas do tipo-A, predominantemente fissurais, de ca 1,87 Ga. Estes arcos magmáticos continentais nomeados Arcos Tapajônicos, tem rochas excepcionalmente bem preservadas de processos tectônicos e metamórficos, o que tem permitido caracterizar os sistemas geológicos, os ambientes tectônicos de formação, os sistemas magmáticos-hidrotermais do tipo epitermal e pórfiro associados, por vezes mineralizados em metais preciosos e de base. Estes arcos são compostos por rochas graníticas diversas, faneríticas e porfiríticas, granófiros, pórfiros riolíticos a andesíticos, andesitos, dacitos, riodacitos e riolitos, estes em maior volume. As rochas vulcânicas compõem derrames, domos e diques, comumente com fácies variadas de rochas vulcanoclásticas associadas, incluindo grandes depósitos de ignimbritos, assim como rochas sedimentares clasticas típicas de ambiente continental deposicional incluindo depósitos de leques aluviais e fluviais compostos por arenitos, conglomerados, siltitos e argilitos junto com unidades lacustres, representadas por lamitos vermelhos com leitos de chert contemporâneas aos eventos vulcânicos paleproterozóicos. As rochas destes arcos são em geral peraluminosas a metaluminosas e pertencem à serie cálcio-alcalina enriquecida em potássio, com tendências shoshoníticas, e mostram semelhança às geradas pelo magmatismo sin- a pós-orogênico em ambiente de arco vulcânico continental maturo, desenvolvido em margens continentais ativas. Dados isotópicos de Sm-Nd de um conjunto representativo de amostras da região indicam valores de \'\'épsilon\'IND.Nd\' negativos e valores baixos de 87Sr/86Sr, indicando a existência de importante contaminação de crosta continental. As idades modelos TDM indicam participação de crosta paleoproterozóica e arqueana na formação dos magmas. Tanto os dados isotópicos como os de magnetometria e de gravimetria indicam que estruturas profundas da região têm orientação geral aproximadamente E-W que parecem constituir extensões das zonas de cisalhamento arqueanas presentes na Província Mineral de Carajás até a altura do rio Tapajós. Em diversos litótipos sub-vulcânicos e vulcânicos mais ou menos evoluídos foram identificadas inúmeras ocorrências de alterações hidrotermais do tipo quartzo-sericita, por vezes com adulária, e argílica, está dominantemente em estilo fissural, que podem ser associadas a mineralizações epitermais do tipo low-sulfidation. Também estão presentes rochas hidrotermalizadas com pirofilita e alunita, caracterizando zonas de alterações argílicas avançadas em estilos pervasivo e fissural, típicas de mineralizações epitermais high-sulfidation. Em todos os litótipos, mas predominantemente em granitoides e pórfiros, foram identificadas alterações potássicas, sericítica, sericita-clorítica, propílitica e clorítica nos estilos pervasivo e fissural, as quais são representativas de típicos sistemas do tipo pórfiro. As fontes dos fluidos responsáveis pela alteração hidrotermal associada aos sistemas epitermais high- e low-sulfidation foram determinadas utilizando análises de isótopos de oxigênio e deutério em pares de minerais (quartzo-sericita e quartzo-caulinita) constituintes das zonas de alteração hidrotermal. Estes resultados indicam fluidos de origem magmática com misturas subordinadas de fluidos meteóricos de baixa latitude, sem a influência de água de degelo. Os valores de ?34Ssulfetos de pirita da rocha hidrotermalizada variam de +0,8 e +9,4 ?, confirmando a hipótese de fonte magmática também para o enxofre. Essas características são semelhantes às observadas em pórfiros cenozoicos de arcos magmáticos continentais e insulares. Estes resultados indicam um importante potencial para ocorrência de mineralizações de metais preciosos (Au e Ag) e de base (Cu, Pb, Zn e Mo) dos tipos epitermal e pórfiro na região, o que abre possibilidades para existência de mineralizações de grande porte nos arcos Tapajônicos, semelhantes àquelas presentes em arcos modernos, como os Andes, México e oeste dos Estados Unidos. E, caso isto venha a se confirmar, haverá um significativo impacto positivo para região, tanto econômico como social. A evolução geotectônica que deu origem aos eventos magmáticos continentais desenvolvidos no período 2,1 a 1,86 Ga definem a evolução metalogenética da Província Mineral do Tapajós. Os dados geocronológicos obtidos neste estudo mostram a existência no embasamento de rochas com idades de ca. 2,12 a 2,02, de 1,97 a 1,95 e de 1,89 Ga, que podem ser correlacionadas às rochas das suítes intrusivas Cuiú-Cuiú, Creporizão e Parauari, assim como rochas hipoabissais (pórfiros) de idades ca. 1,98 a 1,95 e 1,87 correlacionadas com a suíte intrusiva Creporizão e Parauari. As rochas vulcânicas cálcio-alcalinas tradicionalmente reconhecidas como pertencentes ao Grupo Iriri apresentam neste estudo idades de ca. 2,0 Ga, de 1,97 a 1,95 Ga e de 1,90 a 1,88 Ga, enquanto que vulcânicas alcalinas do tipo-A evidenciam idades de 1,87 a 1,85 Ga, indicando que há mais de um evento vulcânico além do magmatismo que deu origem ao Grupo Iriri. Estes resultados indicam uma evolução complexa do magmatismo paleoproterozóico das unidades reconhecidas como suítes magmáticas Cuiú-Cuiú, Creporizão e Parauari, dentro do evento magmático sensu lato Uatumã. Foram reconhecidas ao menos quatro épocas metalogenéticas potencialmente férteis para mineralizações magmáticas-hidrotermais relacionadas com os arcos Tapajônicos gerados no evento sensu lato Uatumã, associadas a períodos de aumento da espessura cortical durante o Peloproterozóico no sul da Província Mineral de Tapajós, quais sejam: a) o período de 2,1 a 1,97 Ga onde se dá a evolução dos arcos magmáticos continentais Cuiú- Cuiú e Creporizão, correlacionáveis com duas épocas de mineralizações magmáticas- hidrotermais de ca. 2 Ga e de 1,97 Ga; b) O período ao redor de 1,95; e c) o período de 1,90 a 1,88 Ga, relacionado ao arco continental Parauari. / The lato sensu Uatumã event is characterized by intense magmatism of calc-alkaline affinity, related to the presence of Paleoproterozoic continental volcanic arcs in a period between 2.1 to 1.88 Ga, associated with the magmatic suites Cuiú-Cuiú, Creporizão, Parauari, with significant relevance in the metallogenic potential in the southern portion of the Amazonian Craton, specifically in the Tapajós Mineral Province. It also includes alkaline volcanic rocks (A-type) of fissural predominance, about 1.87 Ga. These continental magmatic arcs named Tapajônicos arcs, have exceptionally wellpreserved rocks from tectonic and metamorphic processes, which has allowed to characterize the geologic systems, tectonic settings of formation of the associated epithermal- and porphyry-types magmatic-hydrothermal systems, sometimes mineralized in precious and base metals. These arcs are composed of several granitic rocks, phaneritic and porphyritic, granophyres, rhyolitic to andesitic porphyries, andesites, dacites, rhyodacites and rhyolites, these in larger volume. Volcanic rocks make up lava flows, domes and dikes, commonly with varying facies of associated volcanoclastic rocks, including large deposits of ignimbrites, as well as clastic sedimentary rocks of a continental depositional environment including deposits of alluvial and fluvial fans composed of sandstones, conglomerates, siltstones and argillites along with lacustrine units, represented by red mudstones with beds of chert, contemporaneous with the Paleoproterozoic volcanic events. The rocks of these arcs are generally peraluminous to metaluminous, belonging to the high K calc-alkaline series, trending to the shoshonitic series, and they show similarity to those generated by syn- to post-orogenic magmatism in a mature continental volcanic arc, developed in active continental margins. Sm-Nd isotopic data of a representative set of samples from the region indicate negative \'\'épsilon\'IND.Nd\' values and low values of 87Sr / 86Sr, indicating the existence of important continental crust contamination. The TDM model ages indicate participation of Paleoproterozoic and Archaean crust in the formation of magmas. Both isotopic, magnetometric and gravimetric data indicate that deep structures in the region have roughly E-W orientation that appear to constitute extensions of the Archaean shear zones present in the Carajás Mineral Province up to the Tapajós River. Numerous occurrences of quartz-sericite hydrothermal alterations, sometimes with adularia and argillic type, predominantly in fissural style, have been identified in several evolved volcanic and volcanic lithotypes that could be associated with low-sulfidation epithermal mineralizations. Hydrothermalized rocks with pyrophyllite and alunite are also present, characterizing zones of advanced argillic alteration in pervasive and fissural styles, typical of high-sulfidation epithermal mineralizations. In all lithotypes, but predominantly in granitoids and porphyries, were identified potassic, sericitic, sericitic-chloritic, propylitic and chloritic alterations in pervasive and fissural styles, which are representative of typical porphyry-type systems. The sources of the fluids responsible for the hydrothermal alteration associated with high- and low-sulfidation epithermal systems were determined using oxygen and deuterium isotope analyses in minerals pairs (quartz-sericite and quartz-kaolinite) constituents from hydrothermal alteration zones. These results indicate fluids of magmatic origin with subordinate mixtures of low latitude meteoric fluids, without the influence of de-icing water. The values of ?34Ssulfide values of pyrite from hydrothermalized rock range from +0.8 and +9.4 ?, confirming also the hypothesis of a magmatic sulfur source. These characteristics are similar to those observed in Cenozoic porphyries from continental and island magmatic arcs. These results indicate an important potential for the occurrence of precious metals (Au and Ag) and base metals (Cu, Pb, Zn and Mo) of the epithermal and porphyry types in the region, which opens possibilities for large mineralizations in the Tapajônicos arcs, similar to those present in modern arcs, like the Andes, Mexico and western of the United States. And, if this is to be confirmed, there will be a significant positive impact for the region, both economic and social. The geotectonic evolution that gave origin to the continental magmatic events developed in the period between 2.1 to 1.86 Ga define the metallogenic evolution of the Tapajós Mineral Province. The geochronological data obtained in this study show the existence in the basement of rocks with ages of ca. 2.12 to 2.02, from 1.97 to 1.95 and 1.89 Ga, which can be correlated to rocks of the Cuiú-Cuiú, Creporizão and Parauari intrusive suites, as well as hypoabissal (porphyries) rocks of ca. 1.98 to 1.95 Ga and 1.87 Ga correlated with the Creporizão and Parauari intrusive suites. Calc-alkaline volcanic rocks traditionally recognized as belonging to the Iriri Group present in this study have shown ages range of ca. 2.0 Ga, from 1.97 to 1.95 Ga and from 1.90 to 1.88 Ga, while A-type alkaline volcanics yield ages from 1.87 to 1.85 Ga, indicating that there is more than one volcanic event besides the magmatism that gave rise to the Iriri Group. These results indicate a complex evolution of the paleoproterozoic magmatism of the units recognized as Cuiú-Cuiú, Creporizão and Parauari magmatic suites, within lato sensu Uatumã magmatic event. At least four potentially fertile metallogenic epochs were recognized for hydrothermal-magmatic mineralizations related with the Tapajônicos arcs generated in the lato sensu Uatumã event, associated with periods of increase of crustal thickness during the Peloproterozoic in the southern area of the Tapajós Mineral Province, which are: a) the period from 2.1 to 1.97 Ga with the evolution of Cuiú-Cuiú and Creporizão continental magmatic arcs, correlated with two periods of magmatic-hydrothermal mineralizations of ca. 2.0 Ga and 1.97 Ga; b) The period around 1.95 Ga; and c) the period from 1.90 to 1.88 Ga, related with the Parauari continental arc.

O evento sensu lato Uatumã é caraterizado pelo intenso magmatismo de afinidade cálcio-alcalina, relacionado com a presença de arcos vulcânicos continentais Paleoproterozóicos no período 2,1 a 1,88 Ga, associados com as suítes magmáticas Cuiú- Cuiú, Creporizão, Parauari, com significativa relevância no potencial metalogenético na porção sul do Cráton Amazônico, especificamente na Província Mineral do Tapajós. Inclui também as rochas vulcânicas alcalinas do tipo-A, predominantemente fissurais, de ca 1,87 Ga. Estes arcos magmáticos continentais nomeados Arcos Tapajônicos, tem rochas excepcionalmente bem preservadas de processos tectônicos e metamórficos, o que tem permitido caracterizar os sistemas geológicos, os ambientes tectônicos de formação, os sistemas magmáticos-hidrotermais do tipo epitermal e pórfiro associados, por vezes mineralizados em metais preciosos e de base. Estes arcos são compostos por rochas graníticas diversas, faneríticas e porfiríticas, granófiros, pórfiros riolíticos a andesíticos, andesitos, dacitos, riodacitos e riolitos, estes em maior volume. As rochas vulcânicas compõem derrames, domos e diques, comumente com fácies variadas de rochas vulcanoclásticas associadas, incluindo grandes depósitos de ignimbritos, assim como rochas sedimentares clasticas típicas de ambiente continental deposicional incluindo depósitos de leques aluviais e fluviais compostos por arenitos, conglomerados, siltitos e argilitos junto com unidades lacustres, representadas por lamitos vermelhos com leitos de chert contemporâneas aos eventos vulcânicos paleproterozóicos. As rochas destes arcos são em geral peraluminosas a metaluminosas e pertencem à serie cálcio-alcalina enriquecida em potássio, com tendências shoshoníticas, e mostram semelhança às geradas pelo magmatismo sin- a pós-orogênico em ambiente de arco vulcânico continental maturo, desenvolvido em margens continentais ativas. Dados isotópicos de Sm-Nd de um conjunto representativo de amostras da região indicam valores de \'\'épsilon\'IND.Nd\' negativos e valores baixos de 87Sr/86Sr, indicando a existência de importante contaminação de crosta continental. As idades modelos TDM indicam participação de crosta paleoproterozóica e arqueana na formação dos magmas. Tanto os dados isotópicos como os de magnetometria e de gravimetria indicam que estruturas profundas da região têm orientação geral aproximadamente E-W que parecem constituir extensões das zonas de cisalhamento arqueanas presentes na Província Mineral de Carajás até a altura do rio Tapajós. Em diversos litótipos sub-vulcânicos e vulcânicos mais ou menos evoluídos foram identificadas inúmeras ocorrências de alterações hidrotermais do tipo quartzo-sericita, por vezes com adulária, e argílica, está dominantemente em estilo fissural, que podem ser associadas a mineralizações epitermais do tipo low-sulfidation. Também estão presentes rochas hidrotermalizadas com pirofilita e alunita, caracterizando zonas de alterações argílicas avançadas em estilos pervasivo e fissural, típicas de mineralizações epitermais high-sulfidation. Em todos os litótipos, mas predominantemente em granitoides e pórfiros, foram identificadas alterações potássicas, sericítica, sericita-clorítica, propílitica e clorítica nos estilos pervasivo e fissural, as quais são representativas de típicos sistemas do tipo pórfiro. As fontes dos fluidos responsáveis pela alteração hidrotermal associada aos sistemas epitermais high- e low-sulfidation foram determinadas utilizando análises de isótopos de oxigênio e deutério em pares de minerais (quartzo-sericita e quartzo-caulinita) constituintes das zonas de alteração hidrotermal. Estes resultados indicam fluidos de origem magmática com misturas subordinadas de fluidos meteóricos de baixa latitude, sem a influência de água de degelo. Os valores de ?34Ssulfetos de pirita da rocha hidrotermalizada variam de +0,8 e +9,4 ?, confirmando a hipótese de fonte magmática também para o enxofre. Essas características são semelhantes às observadas em pórfiros cenozoicos de arcos magmáticos continentais e insulares. Estes resultados indicam um importante potencial para ocorrência de mineralizações de metais preciosos (Au e Ag) e de base (Cu, Pb, Zn e Mo) dos tipos epitermal e pórfiro na região, o que abre possibilidades para existência de mineralizações de grande porte nos arcos Tapajônicos, semelhantes àquelas presentes em arcos modernos, como os Andes, México e oeste dos Estados Unidos. E, caso isto venha a se confirmar, haverá um significativo impacto positivo para região, tanto econômico como social. A evolução geotectônica que deu origem aos eventos magmáticos continentais desenvolvidos no período 2,1 a 1,86 Ga definem a evolução metalogenética da Província Mineral do Tapajós. Os dados geocronológicos obtidos neste estudo mostram a existência no embasamento de rochas com idades de ca. 2,12 a 2,02, de 1,97 a 1,95 e de 1,89 Ga, que podem ser correlacionadas às rochas das suítes intrusivas Cuiú-Cuiú, Creporizão e Parauari, assim como rochas hipoabissais (pórfiros) de idades ca. 1,98 a 1,95 e 1,87 correlacionadas com a suíte intrusiva Creporizão e Parauari. As rochas vulcânicas cálcio-alcalinas tradicionalmente reconhecidas como pertencentes ao Grupo Iriri apresentam neste estudo idades de ca. 2,0 Ga, de 1,97 a 1,95 Ga e de 1,90 a 1,88 Ga, enquanto que vulcânicas alcalinas do tipo-A evidenciam idades de 1,87 a 1,85 Ga, indicando que há mais de um evento vulcânico além do magmatismo que deu origem ao Grupo Iriri. Estes resultados indicam uma evolução complexa do magmatismo paleoproterozóico das unidades reconhecidas como suítes magmáticas Cuiú-Cuiú, Creporizão e Parauari, dentro do evento magmático sensu lato Uatumã. Foram reconhecidas ao menos quatro épocas metalogenéticas potencialmente férteis para mineralizações magmáticas-hidrotermais relacionadas com os arcos Tapajônicos gerados no evento sensu lato Uatumã, associadas a períodos de aumento da espessura cortical durante o Peloproterozóico no sul da Província Mineral de Tapajós, quais sejam: a) o período de 2,1 a 1,97 Ga onde se dá a evolução dos arcos magmáticos continentais Cuiú- Cuiú e Creporizão, correlacionáveis com duas épocas de mineralizações magmáticas- hidrotermais de ca. 2 Ga e de 1,97 Ga; b) O período ao redor de 1,95; e c) o período de 1,90 a 1,88 Ga, relacionado ao arco continental Parauari. / The lato sensu Uatumã event is characterized by intense magmatism of calc-alkaline affinity, related to the presence of Paleoproterozoic continental volcanic arcs in a period between 2.1 to 1.88 Ga, associated with the magmatic suites Cuiú-Cuiú, Creporizão, Parauari, with significant relevance in the metallogenic potential in the southern portion of the Amazonian Craton, specifically in the Tapajós Mineral Province. It also includes alkaline volcanic rocks (A-type) of fissural predominance, about 1.87 Ga. These continental magmatic arcs named Tapajônicos arcs, have exceptionally wellpreserved rocks from tectonic and metamorphic processes, which has allowed to characterize the geologic systems, tectonic settings of formation of the associated epithermal- and porphyry-types magmatic-hydrothermal systems, sometimes mineralized in precious and base metals. These arcs are composed of several granitic rocks, phaneritic and porphyritic, granophyres, rhyolitic to andesitic porphyries, andesites, dacites, rhyodacites and rhyolites, these in larger volume. Volcanic rocks make up lava flows, domes and dikes, commonly with varying facies of associated volcanoclastic rocks, including large deposits of ignimbrites, as well as clastic sedimentary rocks of a continental depositional environment including deposits of alluvial and fluvial fans composed of sandstones, conglomerates, siltstones and argillites along with lacustrine units, represented by red mudstones with beds of chert, contemporaneous with the Paleoproterozoic volcanic events. The rocks of these arcs are generally peraluminous to metaluminous, belonging to the high K calc-alkaline series, trending to the shoshonitic series, and they show similarity to those generated by syn- to post-orogenic magmatism in a mature continental volcanic arc, developed in active continental margins. Sm-Nd isotopic data of a representative set of samples from the region indicate negative \'\'épsilon\'IND.Nd\' values and low values of 87Sr / 86Sr, indicating the existence of important continental crust contamination. The TDM model ages indicate participation of Paleoproterozoic and Archaean crust in the formation of magmas. Both isotopic, magnetometric and gravimetric data indicate that deep structures in the region have roughly E-W orientation that appear to constitute extensions of the Archaean shear zones present in the Carajás Mineral Province up to the Tapajós River. Numerous occurrences of quartz-sericite hydrothermal alterations, sometimes with adularia and argillic type, predominantly in fissural style, have been identified in several evolved volcanic and volcanic lithotypes that could be associated with low-sulfidation epithermal mineralizations. Hydrothermalized rocks with pyrophyllite and alunite are also present, characterizing zones of advanced argillic alteration in pervasive and fissural styles, typical of high-sulfidation epithermal mineralizations. In all lithotypes, but predominantly in granitoids and porphyries, were identified potassic, sericitic, sericitic-chloritic, propylitic and chloritic alterations in pervasive and fissural styles, which are representative of typical porphyry-type systems. The sources of the fluids responsible for the hydrothermal alteration associated with high- and low-sulfidation epithermal systems were determined using oxygen and deuterium isotope analyses in minerals pairs (quartz-sericite and quartz-kaolinite) constituents from hydrothermal alteration zones. These results indicate fluids of magmatic origin with subordinate mixtures of low latitude meteoric fluids, without the influence of de-icing water. The values of ?34Ssulfide values of pyrite from hydrothermalized rock range from +0.8 and +9.4 ?, confirming also the hypothesis of a magmatic sulfur source. These characteristics are similar to those observed in Cenozoic porphyries from continental and island magmatic arcs. These results indicate an important potential for the occurrence of precious metals (Au and Ag) and base metals (Cu, Pb, Zn and Mo) of the epithermal and porphyry types in the region, which opens possibilities for large mineralizations in the Tapajônicos arcs, similar to those present in modern arcs, like the Andes, Mexico and western of the United States. And, if this is to be confirmed, there will be a significant positive impact for the region, both economic and social. The geotectonic evolution that gave origin to the continental magmatic events developed in the period between 2.1 to 1.86 Ga define the metallogenic evolution of the Tapajós Mineral Province. The geochronological data obtained in this study show the existence in the basement of rocks with ages of ca. 2.12 to 2.02, from 1.97 to 1.95 and 1.89 Ga, which can be correlated to rocks of the Cuiú-Cuiú, Creporizão and Parauari intrusive suites, as well as hypoabissal (porphyries) rocks of ca. 1.98 to 1.95 Ga and 1.87 Ga correlated with the Creporizão and Parauari intrusive suites. Calc-alkaline volcanic rocks traditionally recognized as belonging to the Iriri Group present in this study have shown ages range of ca. 2.0 Ga, from 1.97 to 1.95 Ga and from 1.90 to 1.88 Ga, while A-type alkaline volcanics yield ages from 1.87 to 1.85 Ga, indicating that there is more than one volcanic event besides the magmatism that gave rise to the Iriri Group. These results indicate a complex evolution of the paleoproterozoic magmatism of the units recognized as Cuiú-Cuiú, Creporizão and Parauari magmatic suites, within lato sensu Uatumã magmatic event. At least four potentially fertile metallogenic epochs were recognized for hydrothermal-magmatic mineralizations related with the Tapajônicos arcs generated in the lato sensu Uatumã event, associated with periods of increase of crustal thickness during the Peloproterozoic in the southern area of the Tapajós Mineral Province, which are: a) the period from 2.1 to 1.97 Ga with the evolution of Cuiú-Cuiú and Creporizão continental magmatic arcs, correlated with two periods of magmatic-hydrothermal mineralizations of ca. 2.0 Ga and 1.97 Ga; b) The period around 1.95 Ga; and c) the period from 1.90 to 1.88 Ga, related with the Parauari continental arc.

Στη διδακτορική αυτή διατριβή διερευνάται κατά πόσον η τηλεσκόπηση μπορεί να χρησιμεύει ως αρωγός για την κοιτασματολογική έρευνα και ειδικότερα για την εύρεση "στόχων" επιθερμικής μεταλλοφορίας πολύτιμων μετάλλων μέσω της αναγνωρίσεως ηφαιστειακών και τεκτονικών δομών και ζωνών υδροθερμικών εξαλλοιώσεων από αέρος. Το πεδίο έρευνας είναι το μειοκαινικό ηφαιστειακό-γεωθερμικό πεδίο της νήσου Λέσβου. Ερευνάται η ορυκτολογία των μεταλλικών ορυκτών και συνοδευόντων ορυκτών εξαλλοίωσης. Γίνονται πάραυτα μικροθερμομετρικοί προσδιορισμοί, προσδιορισμοί χρυσού-αργύρου, ιχνοστοιχείων- ιχνηλατών και άλλων ιχνοστοιχείων στις περιοχές-στόχους και τα γεωχημικά δεδομένα τίθενται σε περιβάλλον GIS (θεματικοί χάρτες). / In this phd dissertation it is investigated if remote sensing techniques can be used successfully as an aid in the ore deposits research and specifically for the localization by air "target" areas of epithermal mineralization of precious metals through the recognition of volcanic and tectonic structures and detection of hydrothermal alteration zones. The research area is the miocene volcanic-geothermal field of the island of Lesvos. The research includes also identification of ore and alteration minerals microthermometric measurements, measurement of the Au-Ag parts, of pathfinder and other trace elements in the target areas. The geochemical data are subsequently placed in a GIS environment for future research and/or mineral exploration purposes.

Abstract The metamorphosed Palaeoproterozoic Orivesi gold deposit in southern Finland is located within the Tampere Schist Belt, which belongs to the Svecofennian domain. The Orivesi mine, run by Outokumpu Mining Oy, was in production from 1994 to 2003, during which time a total of approximately 1.7 million tons of ore was extracted, with an Au content of 9.31 g/t, implying a total output 13.115 tons of gold in concentrate. The hydrothermal alteration halo can be divided successively into chlorite-dominant, sericite-dominant and quartz-dominant rocks from the outer zone inwards. The host rocks of the ore are quartz rocks with andalusite-rich quartz rocks. Topaz-bearing rocks also occur in the inner part of the alteration halo. In addition to Au, the elements Ag, Te, Bi, Sb, S, As, Se, Cu, Zn, Pb, Sn and Mo are enriched to varying degrees within the alteration halo. The main ore minerals include base metal sulphides, sulphosalts and tellurides. Pyrite is the most common sulphide. The sulphosalts are represented by tetrahedrite, bournonite, boulangerite and meneghinite. The most common gold, gold-silver and silver tellurides are calaverite, montbrayite, petzite, kostovite, sylvanite and hessite. Other known tellurides include tellurobismuthite, altaite, melonite, frohbergite, tsumoite, tetradymite and rucklidgeite. Gold occurs mostly in fine-grained native grains containing an average of 5% Ag. The native gold is usually of very small grain size, generally &lt; 20 µm. Most of the gold grains in the deposit occur as intergrowths with tellurides. The adjacent hypabyssal intrusion is an obvious source of both hydrothermal fluids and metals. A comb quartz layering has been discovered in the transition zone between the intrusion and the alteration halo. The Orivesi deposit is thought to belong to the high-sulphidation epithermal type. Soon after its formation the deposit encountered deformation and metamorphism that amounted to lower amphibolite facies conditions. The subsequent retrograde metamorphism caused the reappearance of some hydrothermal minerals typical of high-sulphidation epithermal deposits.

No description available.

Fluid inclusion and mineralogical features indicative of boiling have been characterized in 855 samples from epithermal precious metals deposits along the Veta Madre at Guanajuato, Mexico. Features associated with boiling that have been identified at Guanajuato include colloform texture silica, plumose texture silica, moss texture silica, ghost-sphere texture silica, lattice-bladed calcite, lattice-bladed calcite replaced by quartz and pseudo-acicular quartz after calcite and coexisting liquid-rich and vapor-rich fluid inclusions. Most samples were assayed for Au, Ag, Cu, Pb, Zn, As and Sb, and were divided into high-grade and low-grade samples based on the gold and silver concentrations. For silver, the cutoff for high grade was 100 ppm Ag, and for gold the cutoff was 1 ppm Au. The feature that is most closely associated with high grades of both gold and silver is colloform texture silica, and this feature also shows the largest difference in grade between the presence or absence of that feature (178.8 ppm Ag versus 17.2 ppm Ag, and 1.1 ppm Au versus 0.2 ppm Au). For both Ag and Au, there is no significant difference in average grade as a function of whether or not coexisting liquid-rich and vapor-rich fluid inclusions are present. The textural and fluid inclusion data obtained in this study were analyzed using the binary classifier within SPSS Clementine. The models that correctly predicted high versus low grade samples most consistently (~70-75% of the tests) for both Ag and Au were the neural network, the C5 decision tree and Quest decision tree models. For both Au and Ag, the presence of colloform silica texture was the variable with the greatest importance, i.e., the variable that has the greatest predictive power. Boiling features are absent or rare in samples collected along a traverse perpendicular to the Veta Madre. This suggests that if an explorationist observes these features in samples collected during exploration that an environment favorable to precious metal mineralization is nearby. Similarly, good evidence for boiling is observed in the deepest levels of the Veta Madre that have been sampled in the mines and drill cores, suggesting that additional precious metal reserves are likely beneath the deepest levels sampled. / Master of Science

A Província Aurífera de Alta Floresta insere-se na porção sul do Cráton Amazônico e constitui uma região alongada na direção WNW-ESSE onde se situam depósitos auríferos associados ao magmatismo plutonovulcânico Paleoproterozoico. A área pesquisada abrange o garimpo de ouro do Papagaio, situado em Paranaíta, Mato Grosso. Durante o mapeamento geológico, foram identificados corpos de rochas plutônicas a subvulcânicas de composições granodiorítica e granítica, além de rochas vulcânicas e piroclásticas dacíticas e riolíticas. Estes litotipos são pertencentes à série calcioalcalina de médio a alto potássio, meta- a peraluminosas correspondentes a granitos do tipo I de arco vulcânico em margem continental ativa. As idades U-Pb mostraram que o magmatismo na região ocorreu aproximadamente entre 1.80 - 1.78 Ga. com zircões herdados de até 2,1 Ga, mostrando evidências da existência de uma crosta mais profunda e antiga durante a subducção. Os dados de \'épsilon\'Nd(t) mostraram a existência de contribuição crustal e mantélica na fonte de idade TDM entre 2.15-2.02 Ga. Estes dados revelaram que o vulcanismo na área é pertencente a Suíte Colíder, correspondente de um magmatismo que ficou ativo por aproximadamente 16 Ma e que evoluiu de composição dacítica a riolítica. A lavra garimpeira ocorre sobre uma mineralização aurífera com cobre, zinco e baixos teores de chumbo, preferencialmente confinada em veios que cortam os halos de alteração potássica, sericítica e propilítica. Os veios existentes na região evoluem de forma sistematica em seis tipos: (I) Veio de quartzo estéril associado ao halo da alteração potássica; (II) Veio de quartzo com minerais de minério, por vezes, associado ao halo sericítico; (III) Veio sulfetado com halo de alteração sericítica bem desenvolvido nas salbandas; (IV) e (V) Veios de quartzo e carbonato tardios; (VI) sistema de veios de quartzo mais novo e sem relação com a evolução do depósito. Os três primeiros tipos são semelhantes ao sistema A-B-D descrito em depósitos do tipo pórfiro, enquanto que os mais novos apresentam características de um ambiente mais raso e epitermal. O ouro ocorre principalmente na zona central dos veios do tipo II, em paragênese com a calcopirita + esfalerita + pirita ± galena ± magnetita. O quartzo dos veios sofreu diferentes intensidades de recristalização decorrente de subsequentes pulsos hidrotermais e as imagens de catodoluminescência mostraram que as inclusões fluidas aquocarbônicas representam fluidos primários com importante participação no transporte de conteúdo metalífero. Os resultados de isótopos estáveis de D, O e S em quartzo, sericita e pirita hidrotemais mostram que os fluidos são magmáticos com contribuições de fluidos meteóricos. Neste contexto, o Garimpo do Papagaio se desenvolveu sobre um arco magmático continental, a partir da intrusão de corpos graníticos hidratados e oxidados que marcam o evento magmático final da Suíte Colíder. Representa um depósito do tipo pórfiro que foi sobreposto por características epitermais intermediate-sulfidation, como resultado da telescopagem hidrotermal consequente do rebaixamento da câmara magmática. / The Alta Floresta Gold Province is situated on the southern portion of Amazonian Craton and forms an elongate region with WNW-ESSE direction where auriferous deposits are associated with Paleoproterozoic plutonovolcanic magmatism. The area of research covers the Papagaio artisanal gold mining, located in Paranaíta, Mato Grosso. During geological mapping, plutonic to subvolcanic rocks bodies of granodioritic and granitic compositions were identified, as well as dacitic and rhyolitic volcanic and pyroclastic rocks. These lithotypes belong to the calc-alkaline series of medium to high potassium, meta- to peraluminous corresponding to type I granites of volcanic arc in an active continental margin. U-Pb ages showed that magmatism in the region has crystallized in the range of 1.80-1.78 Ga with inherited zircons up to 2.1 Ga, showing evidence of a deeper and older crust during subduction. \'épsilon\'Nd (t) data showed the contribution of crustal and mantle material in the source with TDM age between 2.15- 2.02 Ga. These data revealed that volcanism in the area belongs to the Colíder Suite, corresponding to a magmatism that was active for approximately 16 Ma and evolved from dacitic to a rhyolitic composition. The mining prospect occurs on gold mineralization with copper, zinc and low levels of lead, preferably confined in veins that cut potassic, seritic and propylitic alteration halos. The existing veins in the region evolve systematically into six types: (I) Barren quartz vein associated with potassic alteration halo; (II) Quartz vein with ore minerals, sometimes associated with sericitic halo; (III) Sulphide vein with a well developed sericitic alteration halo in the salbands; (IV) and (V) Late quartz and carbonate veins; (VI) system of quartz veins newer and unrelated to deposit evolution. The first three types are similar to A-B-D system described in porphyry deposits, while the newer ones have characteristics of a shallower and epithermal environment. Gold occurs mainly in the central zone of the type II veins, in paragenesis with chalcopyrite + sphalerite + pyrite ± galena ± magnetite. The quartz of the veins underwent different intensities of recrystallization due to subsequent hydrothermal pulses and cathodoluminescence images showed that aquocarbonic fluid inclusions represent primary fluids with important participation in metalliferous content transportation. The results of D, O and S stable isotope in hydrothermal quartz, sericite and pyrite show that fluids are magmatic with meteoric contributions. In this context, the Papagaio artisanal mining developed on a continental magmatic arc, from the intrusion of hydrated and oxidized granite bodies that mark the final magmatic event of the Colíder Suite. It represents a porphyry deposit that was superimposed by epithermal intermediate-sulfidation characteristics as a result of hydrothermal telescoping, resulting from the lowering of the magma chamber.

A Província Aurífera de Alta Floresta insere-se na porção sul do Cráton Amazônico e constitui uma região alongada na direção WNW-ESSE onde se situam depósitos auríferos associados ao magmatismo plutonovulcânico Paleoproterozoico. A área pesquisada abrange o garimpo de ouro do Papagaio, situado em Paranaíta, Mato Grosso. Durante o mapeamento geológico, foram identificados corpos de rochas plutônicas a subvulcânicas de composições granodiorítica e granítica, além de rochas vulcânicas e piroclásticas dacíticas e riolíticas. Estes litotipos são pertencentes à série calcioalcalina de médio a alto potássio, meta- a peraluminosas correspondentes a granitos do tipo I de arco vulcânico em margem continental ativa. As idades U-Pb mostraram que o magmatismo na região ocorreu aproximadamente entre 1.80 - 1.78 Ga. com zircões herdados de até 2,1 Ga, mostrando evidências da existência de uma crosta mais profunda e antiga durante a subducção. Os dados de \'épsilon\'Nd(t) mostraram a existência de contribuição crustal e mantélica na fonte de idade TDM entre 2.15-2.02 Ga. Estes dados revelaram que o vulcanismo na área é pertencente a Suíte Colíder, correspondente de um magmatismo que ficou ativo por aproximadamente 16 Ma e que evoluiu de composição dacítica a riolítica. A lavra garimpeira ocorre sobre uma mineralização aurífera com cobre, zinco e baixos teores de chumbo, preferencialmente confinada em veios que cortam os halos de alteração potássica, sericítica e propilítica. Os veios existentes na região evoluem de forma sistematica em seis tipos: (I) Veio de quartzo estéril associado ao halo da alteração potássica; (II) Veio de quartzo com minerais de minério, por vezes, associado ao halo sericítico; (III) Veio sulfetado com halo de alteração sericítica bem desenvolvido nas salbandas; (IV) e (V) Veios de quartzo e carbonato tardios; (VI) sistema de veios de quartzo mais novo e sem relação com a evolução do depósito. Os três primeiros tipos são semelhantes ao sistema A-B-D descrito em depósitos do tipo pórfiro, enquanto que os mais novos apresentam características de um ambiente mais raso e epitermal. O ouro ocorre principalmente na zona central dos veios do tipo II, em paragênese com a calcopirita + esfalerita + pirita ± galena ± magnetita. O quartzo dos veios sofreu diferentes intensidades de recristalização decorrente de subsequentes pulsos hidrotermais e as imagens de catodoluminescência mostraram que as inclusões fluidas aquocarbônicas representam fluidos primários com importante participação no transporte de conteúdo metalífero. Os resultados de isótopos estáveis de D, O e S em quartzo, sericita e pirita hidrotemais mostram que os fluidos são magmáticos com contribuições de fluidos meteóricos. Neste contexto, o Garimpo do Papagaio se desenvolveu sobre um arco magmático continental, a partir da intrusão de corpos graníticos hidratados e oxidados que marcam o evento magmático final da Suíte Colíder. Representa um depósito do tipo pórfiro que foi sobreposto por características epitermais intermediate-sulfidation, como resultado da telescopagem hidrotermal consequente do rebaixamento da câmara magmática. / The Alta Floresta Gold Province is situated on the southern portion of Amazonian Craton and forms an elongate region with WNW-ESSE direction where auriferous deposits are associated with Paleoproterozoic plutonovolcanic magmatism. The area of research covers the Papagaio artisanal gold mining, located in Paranaíta, Mato Grosso. During geological mapping, plutonic to subvolcanic rocks bodies of granodioritic and granitic compositions were identified, as well as dacitic and rhyolitic volcanic and pyroclastic rocks. These lithotypes belong to the calc-alkaline series of medium to high potassium, meta- to peraluminous corresponding to type I granites of volcanic arc in an active continental margin. U-Pb ages showed that magmatism in the region has crystallized in the range of 1.80-1.78 Ga with inherited zircons up to 2.1 Ga, showing evidence of a deeper and older crust during subduction. \'épsilon\'Nd (t) data showed the contribution of crustal and mantle material in the source with TDM age between 2.15- 2.02 Ga. These data revealed that volcanism in the area belongs to the Colíder Suite, corresponding to a magmatism that was active for approximately 16 Ma and evolved from dacitic to a rhyolitic composition. The mining prospect occurs on gold mineralization with copper, zinc and low levels of lead, preferably confined in veins that cut potassic, seritic and propylitic alteration halos. The existing veins in the region evolve systematically into six types: (I) Barren quartz vein associated with potassic alteration halo; (II) Quartz vein with ore minerals, sometimes associated with sericitic halo; (III) Sulphide vein with a well developed sericitic alteration halo in the salbands; (IV) and (V) Late quartz and carbonate veins; (VI) system of quartz veins newer and unrelated to deposit evolution. The first three types are similar to A-B-D system described in porphyry deposits, while the newer ones have characteristics of a shallower and epithermal environment. Gold occurs mainly in the central zone of the type II veins, in paragenesis with chalcopyrite + sphalerite + pyrite ± galena ± magnetite. The quartz of the veins underwent different intensities of recrystallization due to subsequent hydrothermal pulses and cathodoluminescence images showed that aquocarbonic fluid inclusions represent primary fluids with important participation in metalliferous content transportation. The results of D, O and S stable isotope in hydrothermal quartz, sericite and pyrite show that fluids are magmatic with meteoric contributions. In this context, the Papagaio artisanal mining developed on a continental magmatic arc, from the intrusion of hydrated and oxidized granite bodies that mark the final magmatic event of the Colíder Suite. It represents a porphyry deposit that was superimposed by epithermal intermediate-sulfidation characteristics as a result of hydrothermal telescoping, resulting from the lowering of the magma chamber.