In exploration, a lithogeochemical approach can be used to aid the characterisation of rocks surrounding metamorphosed and hydrothermally altered deposits. Accurate description of the geological setting of deposits is crucial for understanding the ore forming processes and identifying targets for exploration. The Svärdsjö Zn-Pb-Cu deposit is located in the heavily mineralised and metamorphosed Bergslagen ore province of south-central Sweden. The deposit and surrounding minor occurrences were actively mined for over 500 years, producing more than 1 Mt of Zn-Pb-Cu-Ag massive sulphide ore. The combination of strongly metamorphosed and hydrothermally altered rocks in Svärdsjö makes geological interpretation challenging. Therefore, an approach combining lithogeochemical and petrographic methods is used in this study. The characterisation of the rocks and hydrothermal alteration surrounding the deposit allowed for an interpretation of ore formation and its implications for further exploration in the Svärdsjö area. The results verified that the Svärdsjö mineralisations are hosted by 2–15 m thick dolomitic marble units, commonly altered to skarn. Surrounding the deposit are subvolcanic intrusions and volcanoclastic rocks of mainly dacitic composition. The combined approach also helped identifying a strong to intense hydrothermal chlorite-sericite alteration enveloping the mineralised marble units and resulted in large mass gains of Fe and Mg whereas Na was depleted. Multiple episodes of alteration and metamorphism are evident from cross-cutting relationships with less altered dykes and overprint by metamorphic minerals such as cordierite and anthophyllite. An ore formation model involving sub-seafloor volcanic-associated replacement is suggested for the Svärdsjö deposit based on (i) the presence of a zoned hydrothermal alteration system within a volcanoclastic rock sequence and (ii) the irregular stratabound sulphide lenses hosted by thin marble units in the centre of the alteration system. Additionally, it is inferred that the stratabound nature of the deposit is caused by the neutralisation of a hot acidic fluid, resulting in precipitation of the sulphides within the marble. Finally, two geochemically distinct lithological units have been identified adjacent to the mineralised zones, providing new, larger exploration targets in the area. Mass change calculations reveal that Fe and Mg enrichment and Na depletion are useful vectors towards mineralisation, with detectable changes extending for up to 100 m from the mineralised lenses. These findings showcase the usefulness of the incorporation and careful interpretation of lithogeochemical data when exploring for metamorphosed hydrothermal ore deposits in mineralised provinces of the Fennoscandian Shield or elsewhere in the world.

The Palaeoproterozoic Dannemora inlier is situated in the north-eastern Bergslagen region. The inlier consists of primary and reworked volcanic deposits, stromatolitic limestone and skarn that have been subjected to upper greenschist facies metamorphism. Thicknesses of the different volcanic deposits indicate deposition within a caldera, where syn-volcanic alkali alteration was strong. The deposition was submarine and below wave base in the eastern part of the inlier, but above wave base in the central part where erosion channels together with cross-bedding occurs frequently. The Dannemora Formation is the volcanosedimentary succession of the inlier. Two borehole profiles, a northern and a southern, cover the whole Formation and show different alteration patterns. A strong depletion of Na2O and enrichment of K2O dominate in the southern profile, whereas this pattern is not as evident in the northern profile. The uppermost section of the totally eight constituting the Formation, is intercalated with ore-bearing dolomitic limestone and skarn, and has experienced at least two episodes of alteration. An anticline has been established lithogeochemically from immobile element ratios and the reoccurrence of an accretionary lapilli bed. Numerous altered sub-alkaline, calc-alkaline and basaltic dykes have been recorded in the Dannemora inlier. They are the result of mixing and fractionation of at least three magmatic sources and carry a mixed signature of subduction zone and within-plate volcanic tectonic setting. A seismic profile across the Dannemora inlier images a strong reflector package that dips c. 50° E to the east of the inlier. This package coincides with the polyphase, E-up reverse, brittle-ductile Österbybruk deformation zone (ÖDZ). Yet another steep reflector in the Dannemora ore-field extends to a depth of more than two kilometres. This reflector might represent either a deep-seated iron deposit or a fluid-bearing fault zone.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A Unidade Santo Aleixo, em sua localidade-tipo, é representada por gnaisses homogêneos, e, mais restritamente, por gnaisses bandados e gnaisses com inclusões máficas e félsicas. Todos os tipos litológicos mostram contatos gradacionais entre si. Na área de pesquisa, ocorrem ainda leucognaisses, migmatitos, granitos tardios e diques de diabásio. A área é marcada por foliação principal com trend NE e mergulho de baixo a médio ângulo, ora para SE ora para NW, relacionado a dobramento com traço do plano axial NE-SW. Foram descritas zonas de cisalhamento dúcteis a rúpteis de fases deformacionais tardias. A análise modal dos diversos tipos gnáissicos revelou uma composição tonalítica a granítica e menos comumente, quartzo-monzodiorítica e quartzo-monzonitica. A biotita está sempre presente podendo ou não vir acompanhada de hornblenda. Os acessórios mais comuns nessas rochas são apatita, zircão e opacos, enquanto titanita e allanita são mais variáveis, e às vezes podem estar ausentes. É rara a presença de granada que apenas foi observada em uma amostra do gnaisse homogêneo. Observou-se cloritização de biotita e sericitização e formação de muscovita a partir de plagioclásio. Os resultados geoquímicos apontam para a existência de apenas um grupo subalcalino disposto ao longo de um trend calci-alcalino. A maioria das amostras são metaluminosas a fracamente peraluminosas. Os gnaisses apresentam valores de terras raras pesadas inferiores a 10 ppm, o que resulta em elevadas razões (La/Lu)N. As comparações petrográficas e litogeoquímicas entre a Unidade Santo Aleixo e do Complexo Rio Negro mostram que: a) a Unidade Santo Aleixo compreende uma série petrográfica expandida enquanto que o Complexo Rio Negro é representado por séries mais restritas; b) o quimismo das duas unidades é semelhante, e representa um magmatismo calci-alcalino metaluminoso à biotita e hornblenda; c) as unidades são semelhantes em termos de ambientação tectônica, representando um ambiente do tipo arco vulcânico; d) os gnaisses da Unidade Santo Aleixo são empobrecidos em terras raras pesadas em comparação aos gnaisses do Complexo Rio Negro; comportamento causado pela presença de granada na fonte geradora. A inclusão da Unidade Santo Aleixo no Complexo Rio Negro, portanto, é sustentada pelas semelhanças petrográficas e geoquímicas, entendendo-se que o Complexo inclui tipos magmáticos com modos de evolução e fontes diferentes. / The Santo Aleixo Unit in its type-location is represented by homogenous gneiss and subordinated banded and inclused mafic-felsic-rich gneisses, all rocks separated by gradational contacts. Leucogranitic gneiss, migmatites, late-tectonic granite stocks and diabase dikes also occur in the studied area. The gneissic foliation dips to SE or NW with low to medium angles according to large vertical folds with a NE trending axial plane. The main foliation is deformed by late tectonic ductile to brittle shear zones. The gneisses are classified as tonalites to granites and, subordinated quartz-monzodiorites and quartz-monzonites. Biotite is always present with or without hornblende. Garnet was described only in the homogenous gneiss. Apatite, zircon, opaque minerals and minor titanite and allanite are the acessory minerals. Biotite chloritization and plagioclase sericitization are the observed metamorphic-hidrotermal processes. Lithogeochemical data classify the Santo Aleixo Unit gneisses as metaluminous metaigneous rocks from a calc-alkaline sequence. Heavy REE concentrations are lower than 10 ppm, resulting in elevated (La/Lu)N ratios. Comparing petrographic and lithogeochemical data from the Santo Aleixo Unit and the Rio Negro Complex points to the following statements: a) Santo Aleixo Units petrographic series are expanded while Rio Negro Complexs series are more restricted; b) the units presents same chemical signatures (calc-alkaline volcanic arc metaluminous magmas with biotite and hornblende); c) the Santo Aleixo Unit gneisses are depleted in heavy REE related to the presence of garnet at the magma source. Therefore, the incorporation of the Santo Aleixo Unit into the Rio Negro Complex is sustained by petrographic and lithogeochemical similarities, and also makes clear that the arc magmatism had different sources and evolutionary paths.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A Unidade Santo Aleixo, em sua localidade-tipo, é representada por gnaisses homogêneos, e, mais restritamente, por gnaisses bandados e gnaisses com inclusões máficas e félsicas. Todos os tipos litológicos mostram contatos gradacionais entre si. Na área de pesquisa, ocorrem ainda leucognaisses, migmatitos, granitos tardios e diques de diabásio. A área é marcada por foliação principal com trend NE e mergulho de baixo a médio ângulo, ora para SE ora para NW, relacionado a dobramento com traço do plano axial NE-SW. Foram descritas zonas de cisalhamento dúcteis a rúpteis de fases deformacionais tardias. A análise modal dos diversos tipos gnáissicos revelou uma composição tonalítica a granítica e menos comumente, quartzo-monzodiorítica e quartzo-monzonitica. A biotita está sempre presente podendo ou não vir acompanhada de hornblenda. Os acessórios mais comuns nessas rochas são apatita, zircão e opacos, enquanto titanita e allanita são mais variáveis, e às vezes podem estar ausentes. É rara a presença de granada que apenas foi observada em uma amostra do gnaisse homogêneo. Observou-se cloritização de biotita e sericitização e formação de muscovita a partir de plagioclásio. Os resultados geoquímicos apontam para a existência de apenas um grupo subalcalino disposto ao longo de um trend calci-alcalino. A maioria das amostras são metaluminosas a fracamente peraluminosas. Os gnaisses apresentam valores de terras raras pesadas inferiores a 10 ppm, o que resulta em elevadas razões (La/Lu)N. As comparações petrográficas e litogeoquímicas entre a Unidade Santo Aleixo e do Complexo Rio Negro mostram que: a) a Unidade Santo Aleixo compreende uma série petrográfica expandida enquanto que o Complexo Rio Negro é representado por séries mais restritas; b) o quimismo das duas unidades é semelhante, e representa um magmatismo calci-alcalino metaluminoso à biotita e hornblenda; c) as unidades são semelhantes em termos de ambientação tectônica, representando um ambiente do tipo arco vulcânico; d) os gnaisses da Unidade Santo Aleixo são empobrecidos em terras raras pesadas em comparação aos gnaisses do Complexo Rio Negro; comportamento causado pela presença de granada na fonte geradora. A inclusão da Unidade Santo Aleixo no Complexo Rio Negro, portanto, é sustentada pelas semelhanças petrográficas e geoquímicas, entendendo-se que o Complexo inclui tipos magmáticos com modos de evolução e fontes diferentes. / The Santo Aleixo Unit in its type-location is represented by homogenous gneiss and subordinated banded and inclused mafic-felsic-rich gneisses, all rocks separated by gradational contacts. Leucogranitic gneiss, migmatites, late-tectonic granite stocks and diabase dikes also occur in the studied area. The gneissic foliation dips to SE or NW with low to medium angles according to large vertical folds with a NE trending axial plane. The main foliation is deformed by late tectonic ductile to brittle shear zones. The gneisses are classified as tonalites to granites and, subordinated quartz-monzodiorites and quartz-monzonites. Biotite is always present with or without hornblende. Garnet was described only in the homogenous gneiss. Apatite, zircon, opaque minerals and minor titanite and allanite are the acessory minerals. Biotite chloritization and plagioclase sericitization are the observed metamorphic-hidrotermal processes. Lithogeochemical data classify the Santo Aleixo Unit gneisses as metaluminous metaigneous rocks from a calc-alkaline sequence. Heavy REE concentrations are lower than 10 ppm, resulting in elevated (La/Lu)N ratios. Comparing petrographic and lithogeochemical data from the Santo Aleixo Unit and the Rio Negro Complex points to the following statements: a) Santo Aleixo Units petrographic series are expanded while Rio Negro Complexs series are more restricted; b) the units presents same chemical signatures (calc-alkaline volcanic arc metaluminous magmas with biotite and hornblende); c) the Santo Aleixo Unit gneisses are depleted in heavy REE related to the presence of garnet at the magma source. Therefore, the incorporation of the Santo Aleixo Unit into the Rio Negro Complex is sustained by petrographic and lithogeochemical similarities, and also makes clear that the arc magmatism had different sources and evolutionary paths.

The Rävliden mine is located in the Skellefte district in northern Sweden. In close proximity lays the Kristineberg deposit containing zinc, copper and lead ore which has been mined since the 1940’s. The district is rich in massive sulphide deposits and the mining history can be dated back to the 1920’s. New deposits are still being discovered and understanding the origin of the ores and their formation processes are more and more important when looking for new orebodies. The area itself is ca 1.8 Ga and most rocks have undergone hydrothermal alteration and been metamorphosed. The main purpose of this study was to determine the host rock protolith and the method chosen was developed by MacLean and Barrett (2005) in which immobile element ratios are used for determining the chemostratigraphy.     Two main alteration types are recognized and two minor ones. The dominant ones being sericite and chlorite alteration. The boreholes also display some silicification and carbonate alteration. While the TAS-diagram shows that most samples are either dacitic or rhyolitic with a small group of andesitic rocks. Further usage of both the Alteration box plot and various immobile element plots show that the amount of dacitic samples are low. Instead rhyolite is the predominant rock type with four subgroups, there is also one dacite group and one probable andesitic intrusion. The mineralisation is low so it was not possible to correlate alteration type to ore occurrence, nor was it possible to see any correlation between protolith and mineralisation. The study did determine the protolith for the boreholes and the data and therefore the method can be used for exploration in other areas. / Rävlidengruvan ligger i Skelleftedistriktet i norra Sverige och i dess närhet ligger även  Kritinebergsgruvan där zink, koppar och bly har brutits ur malmkroppen sedan 1940-talet. Distriktet är rikt på massiva sulfid avlagringar och gruvdrift i området kan dateras tillbaka till 1920-talet. Nya fyndigheter upptäcks fortfarande och förståelse för deras uppkomst och malmernas bildningsprocesser blir är allt viktigare när man ska söka nya malmkroppar. Skelleftedistriktet är ca 1,8 Ga och de flesta bergarter har antingen genomgått metamorfos eller hydrotermal omvandling. Huvudsyftet med denna studie var att fastställa ursprungsbergarten för området, innan hydrotermal omvandling skedde, med hjälp av en metod som har utvecklats av MacLean och Barrett. Metoden grundar sig i att man jämför relationerna mellan immobila grundämnen för att på så sätt fastställa kemostratigrafin.     Fyra omvandlingstyper återfinns i borrhålen där två är mer prominenta, serecit och klorit omvandling. De mindre vanliga omvandlingstyperna är silicifiering eller kvartsomvandlig samt karbonatomvandling. De flesta prover är antingen daciter eller ryoliter med en liten grupp andesiter så visar de olika diagrammen med immobila elementet på att mängden daciter är få. Istället finns det fyra typer av ryoliter, en grupp daciter och en trolig andesitisk intrusion. Mängden mineralisering var låg så det var inte möjligt att korrelera omvandlingstyp till malm bildning, inte heller var det möjligt att se något samband mellan protoliten och mineralisering. Studien besvarade hypotesen om ursprungsbergarten för borrhålen och metoden kan användas för andra prospekteringsområden.

Orientador: Guillermo Rafael Beltran Navarro / Resumo: A Formação Corumbataí é uma unidade sedimentar pelítica a psamo-pelítica de idade permiana, pertencente à Supersequência Gondwana I da Bacia do Paraná, sobre a qual poucos estudos foram realizados quanto à proveniência e suas implicações paleoambientais. Este trabalho visa preencher estas lacunas, apresentando correlações de composição e de proveniência entre seções aflorantes da Formação Corumbataí nos município de Rio Claro (SP), Santa Rosa de Viterbo (SP) e Mineiros (GO), e uma seção aflorante da Formação Serra Alta (Permiano da Bacia do Paraná, correlacionável com a base da Formação Corumbataí) no município de Cesário Lange (SP), bem como suas implicações paleoclimáticas, paleogeográficas e possíveis implicações na compreensão dos mecanismos de abertura do Atlântico Sul. Os dados mostram que as rochas permianas sobrejacentes à Formação Irati que ocorrem nas áreas de estudo são classificadas quimicamente com mais frequência como “wackes” e litoarenitos, formados por sedimentos derivados predominantemente de rochas sedimentares e/ou metassedimentares e ígneas ácidas, com a região de Cesário Lange discordando das demais regiões por indicar contribuição exclusiva de rochas supracrustais. Em se tratando das amostras da Formação Corumbataí, a maturidade química e textural aumenta de norte em direção a sul, bem como o grau de submissão dos sedimentos originais ao processo de reciclagem sedimentar. As rochas sedimentares foram depositadas em ambientes tectonicamente quiescentes, ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The Corumbataí Formation is a pelitic to psammo-pelitic sedimentary unit of Permian age, belonging to the Gondwana I Supersequence of the Paraná Basin, about which few studies have been conducted regarding its provenance and its paleoenvironmental implications. This work aims to fill these gaps, presenting correlations of composition and provenance between outcropping sections of the Corumbataí Formation in the municipalities of Rio Claro (SP), Santa Rosa de Viterbo (SP) and Mineiros (GO), and an outcropping section of the Serra Alta Formation (Permian of the Paraná Basin, correlated with the base of the Corumbataí Formation) in the municipality of Cesário Lange (SP), as well as its paleoclimatic and paleogeographic implications and possible implications in the understanding of the opening mechanisms of the South Atlantic. The data show that the Permian rocks overlying the Irati Formation that occur in the study areas are most commonly chemically classified as “wackes” and lithoarenites, formed by sediments derived predominantly from sedimentary and/or metasedimentary and acidic igneous rocks, with Cesário Lange region disagreeing with the other regions as it indicates exclusive contribution of supracrustal rocks. Regarding the Corumbataí Formation samples, the chemical and textural maturity increases from north to south, as well as the degree of submission of the original sediments to the sedimentary recycling process. The sedimentary rocks have been deposited in tectonicall... (Complete abstract click electronic access below) / Doutor

Sixteen samples from 8 locations within and surrounding the Björkdal mine area in northern Sweden were chosen in order to reevaluate and characterize previous interpretations of the lithology and hydrothermal alteration. Geochemical analysis by ICP-MS was made in order to chemically classify the lithology of the area and petrological studies were made by study of thin sections and core logging. Three different sets of major alteration types with similar protolith were noted where two dominated: a) a silicified, sericitic, deformed unit; b) a felspathic altered unit with various intensity of epidote; c) amphibole and a so called green banded unit that has undergone Ca-Mg-metasomatism. The main host rock lithology could be identified as a coarse grained, equigranular, plagioclase and (Na-K)-feldspar dominated rock with slightly elongated, stubby grains that have an interlocked, igneous texture. Apatite is a reoccurring accessory mineral in all samples and remains relatively undamaged. Fragmental quartz occur in the samples and is primary to later forming alteration minerals.Amphiboleis also considered to be primary, but can also been formed during regional metamorphism. Two lithologies could be identified in addition to the main protolith. Two samples were located above the marble horizon and was classified as basaltic unit with Ca-plagioclase, biotite and amphibole. One sample mainly consisted of aligned amphibole and biotite and is considered to be an amphibolite xenolith or a dyke intruding the main protolith rock. An increase in the alteration minerals albite, amphibole, epidote and allanite, with peak intensity found north-east of the mine site. This is confirmed by the geochemistry of major elements Fe2O3, MgO, CaO and the ratio between Na2O and K2O. The zonation is explained by a suggested increase in temperaturecondition during metamorphosis. This could be explained by either an underlying intrusion or bystructurally controlled variation in metamorphism by e.g. major faults running through the area.Comparisons with previous work in Björkdal favors an intrusion-related origin for the gold deposit.

Fundação Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O Complexo Juiz de Fora (CJF) na região de Três Rios (RJ) é constituído por uma ampla variedade composicional, tendo desde granitos, tonalitos a rochas de composição gabróica. Através da litogeoquímica pôde-se subdividir essa unidade em 4 conjuntos: (i) cálcioalcalino de alto-K, (ii) cálcioalcalino de médio-K, (iii) toleítico e (iv) alcalino. Pela análise geocronológica (LA-ICPMS, U-Pb) foi obtida a idade de 2,1Ga para o conjunto cácioalcalino de médio-K, duas idades neoproterozóicas (615.9 6.4 Ma e 589.1 5 Ma) foram datadas em um ortogranulito do conjunto toleítico, que foram interpretadas como sendo idades de metamorfismo. A idade modelo de Nd (≈ 2,37 Ga) e os dados de U-Pb e litogeoquímicos balizam a hipótese do conjunto cálcioalcalino de médio-K representar rochas de um arco magmático juvenil. A análise isotópica em conjunto com a litogeoquímica sugere que a série toleítica do CJF da região estudada foi gerada em ambiente de fundo oceânico, sendo diferenciada a partir de uma fonte depletada com alguma contribuição de uma fonte enriquecida. / The Juiz de Fora Complex (JFC) in the region of Três Rios (Rio de Janeiro) is appointed by an ample variety composicional, having from granites, tonalite to rocks of composition basic. Through the lithogeochemistry it was possible to subdivide this unity in 4 associations: (i) calc-alkaline of high-K, (ii) calc-alkaline of medium-K, (iii) tholeiitic and (iv) alkaline. By the geochronological analysis(LA-ICPMS, U-Pb) was obtained the age of 2,1Ga for the calc-alkaline group of medium-K, two ages neoproterozoic (615.9 6.4 Ma and 589.1 5 Ma) were dated in an orthogranulite of the toleítico group, what they were interpreted like ages of metamorphism. The model age of Nd (≈ 2,37 Ga) and the data of U-Pb and lithogeochemical mark the hypothesis of the calc-alkaline group of middle-K represents rocks of a youthful magmatic arc. The isotópica together with the lithogeochemistry analysis suggests that the toleítica group of the CJF of the studied region were produced in environment of ocean extensional, being differentiated from a fountain depletada with some contribution of a rich fountain.

Fundação Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O Complexo Juiz de Fora (CJF) na região de Três Rios (RJ) é constituído por uma ampla variedade composicional, tendo desde granitos, tonalitos a rochas de composição gabróica. Através da litogeoquímica pôde-se subdividir essa unidade em 4 conjuntos: (i) cálcioalcalino de alto-K, (ii) cálcioalcalino de médio-K, (iii) toleítico e (iv) alcalino. Pela análise geocronológica (LA-ICPMS, U-Pb) foi obtida a idade de 2,1Ga para o conjunto cácioalcalino de médio-K, duas idades neoproterozóicas (615.9 6.4 Ma e 589.1 5 Ma) foram datadas em um ortogranulito do conjunto toleítico, que foram interpretadas como sendo idades de metamorfismo. A idade modelo de Nd (≈ 2,37 Ga) e os dados de U-Pb e litogeoquímicos balizam a hipótese do conjunto cálcioalcalino de médio-K representar rochas de um arco magmático juvenil. A análise isotópica em conjunto com a litogeoquímica sugere que a série toleítica do CJF da região estudada foi gerada em ambiente de fundo oceânico, sendo diferenciada a partir de uma fonte depletada com alguma contribuição de uma fonte enriquecida. / The Juiz de Fora Complex (JFC) in the region of Três Rios (Rio de Janeiro) is appointed by an ample variety composicional, having from granites, tonalite to rocks of composition basic. Through the lithogeochemistry it was possible to subdivide this unity in 4 associations: (i) calc-alkaline of high-K, (ii) calc-alkaline of medium-K, (iii) tholeiitic and (iv) alkaline. By the geochronological analysis(LA-ICPMS, U-Pb) was obtained the age of 2,1Ga for the calc-alkaline group of medium-K, two ages neoproterozoic (615.9 6.4 Ma and 589.1 5 Ma) were dated in an orthogranulite of the toleítico group, what they were interpreted like ages of metamorphism. The model age of Nd (≈ 2,37 Ga) and the data of U-Pb and lithogeochemical mark the hypothesis of the calc-alkaline group of middle-K represents rocks of a youthful magmatic arc. The isotópica together with the lithogeochemistry analysis suggests that the toleítica group of the CJF of the studied region were produced in environment of ocean extensional, being differentiated from a fountain depletada with some contribution of a rich fountain.