No description available.

No description available.

No description available.

Neste trabalho são apresentados novos dados isotópicos de C, O, Sr, Mg e Li e elementares de Elementos Terras Raras (ETR) para as rochas carbonáticas do Grupo Bambuí, no sul da Bacia do São Francisco. Também são apresentadas idades U-Pb e isótopos de Hf em zircão detrítico e dados isotópicos de Sm-Nd em amostras de rocha total de rochas siliciclásticas no mesmo setor da bacia. Os dados quimioestratigráficos permitem dividir as três formações basais do Grupo Bambuí em três intervalos quimioestratigráficos (chemostratigraphic intervals - CI), cada qual registrando um estágio evolutivo da bacia. O CI-1 corresponde à capa carbonática da Formação Sete Lagoas que apresenta excursão isotópica negativa de C, valores de \'delta\'¹³C negativos e razões 87Sr/86Sr crescentes de 0,7074 a 0,7082. Este intervalo marca o início da transgressão marinha que inundou o Cráton do São Francisco onde a bacia estava sujeita a controles locais na química marinha, gerando carbonatos com padrões planares de distribuição normalizada de ETR e com variações acopladas de \'delta\'7Li e \'delta\'26Mg dependentes das fácies sedimentares. O intervalo CI-2 corresponde à porção intermediária da Formação Sete Lagoas na qual foi reportada a ocorrência de Cloudina sp. (550-542 Ma). As rochas carbonáticas deste intervalo apresentam valores de \'delta\'¹³C ao redor de 0%o, \'delta\'7Li ao redor de 16%o, \'delta\'26Mg de aproximadamente -3,5%o e razões 87Sr/86Sr entre 0,7080 e 0,7087, dentro do padrão esperado para o limite Ediacarano-Cambriano. Neste estágio, a transgressão marinha culminou com a conexão da Bacia do São Francisco com outras bacias gondwânicas, permitindo migração de fauna e homogeneização isotópica. Apesar de alguns sinais geoquímicos de caráter global, o cenário intracontinental da bacia a mantinha sujeita a controles locais, observados no enriquecimento de ETR leves em relação aos pesados e por duas excursões negativas nos valores de \'delta\'7Li perfeitamente acopladas a excursões positivas de\'delta\'26Mg. O intervalo CI-3 engloba as formações Sete Lagoas superior, Serra de Santa Helena e Lagoa do Jacaré e seus calcários com valores de \'delta\'¹³C bastante positivos (acima de +3%o) e razões 87Sr/86Sr ao redor de 0,7075, abaixo das esperadas para o limite Ediacarano-Cambriano. O CI-3 marca a restrição da bacia em relação ao reservatório geoquímico e isotópico global, provavelmente pelo soerguimento dos orógenos marginais ao cráton. Tal soerguimento provocou aumento da taxa de denudação e consequente decréscimo da intensidade de intemperismo nas áreas fontes, reduzindo o fluxo dissolvido para a bacia, observado no desacoplamento dos sistemas isotópicos de Mg e Li, e ciclos de decréscimo das razões Sr/Ca e 26Mg removidos pela precipitação carbonática. A diminuição da intensidade de intemperismo e a declividade das áreas fontes tornaram o fluxo dissolvido oriundo de carbonatos mais importantes que os de silicatos, resultando em diminuição das razões 87Sr/86Sr, no aparecimento de distribuições normalizadas de ETR com padrão \"água do mar\", na restrição do suprimento de sulfato na bacia e consequente metanogênese. Os dados geocronológicos mostram que não houve uma reorganização significativa nas áreas de fontes para a bacia desde a deposição das fácies mais finas da Formação Carrancas e Laminito Moema até a deposição da Lagoa do Jacaré. Embora não resolva as principais questões de idade e geotectônicas da bacia, esta constatação é mais um argumento a favor da ausência de uma discordância na base da Formação Sete Lagoas, o que sugere que a glaciação na base da Bacia do São Francisco é provavelmente do Ediacarano Médio / Superior. Se existir esta discordância, a única idade absoluta disponível para a capa carbonática sugere que a glaciação seria Sturtiana (~720 Ma). / This work presents new C, O, Sr, Mg and Li isotope data and Rare Earth Element (REE) concentrations for the carbonate rocks of the Bambuí Group, in the southern São Francisco Basin. U-Pb and Hf geochronology in detrital zircon grains and whole rock Sm-Nd ages in siliciclastic rocks in the same area are also presented. The chemostratigraphic data allow subdividing the three lower units of the Bambuí Group in three Chemostratigraphic Intervals (CI), each one recording a different evolution stage of the basin. The CI-1 comprises the Sete Lagoas Formation cap carbonates that display C isotope negative excursion, very negative \'delta\'¹³C values and 87Sr/86Sr ratios increasing upwards from 0.7074 to 0.7082. This intervals marks the start of the marine transgression over the São Francisco Craton in which the basin was subject to local controls over seawater, as shown by the flat type shale normalized REE distributions and coupled facies dependent \'delta\'Li and \'delta\'26Mg values variations. The CI-2 corresponds to the middle portion of the Sete Lagoas Formation where the Cloudina sp. (550-542 Ma) occurrence was described. The carbonate rocks of this interval display \'delta\'¹³C values around 0%o, \'delta\'7Li values around 16%o, \'delta\'26Mg around -3.5%o and 87Sr/86Sr between 0.7080 and 0.7087 that are expected for the Ediacaran-Cambrian limit. During this stage, the marine transgression provided connection of the São Francisco basin to other West Gondwana basins, allowing fauna migration and isotope homogenization. In spite of the global geochemical signals observed, the intracontinental scenario kept the basin subject to local controls, as shown by the enrichment in light REE and two perfectly coupled \'delta\'7Li and \'delta\'26Mg negative excursions. The CI-3 comprises the limestones of the upper Sete Lagoas, Serra de Santa Helena and Lagoa do Jacaré formations and with very positive \'delta\'¹³C values (> +3%o) and 87Sr/86Sr ratios around 0.7075, lower than those expected for the Ediacaran-Cambrian limit. The CI-3 records the restriction of the basin in relation to the global ocean geochemical and isotope reservoir, probably by the uplift of the craton\"s marginal orogens. Such uplift caused higher denudation rates and consequent decrease in the weathering intensity of the source areas, diminishing the dissolved influx to the basin that is observed in the Mg and Li isotope systems decouplement and in cycles of Sr/Ca ratios and 26Mg decrease by carbonate precipitation removal. The weathering intensity decrease caused the dissolved influx from carbonates to be more important than the one from silicates, resulting in the drop down of the 87Sr/86Sr ratios, the appearance of the \"seawater\" REE shale normalized distributions, and sulphate supply restriction driving methanogenesis. The geochronological data show that no significant reorganization of the basin source areas occurred from the deposition of the Carrancas Formation and Moema Laminites finer facies to the Lagoa do Jacaré Formation. Although the data do not solve the age and geotectonic questions, they add another argument against the existence of an unconformity at the base of the Sete Lagoas Formation, suggesting that the glaciation of the São Francisco Basin is likely Middle to Late Ediacaran in age. If there is an unconformity, the only available absolute age suggests it is a Sturtian Glaciation (~720 Ma).

Neste trabalho são apresentados novos dados isotópicos de C, O, Sr, Mg e Li e elementares de Elementos Terras Raras (ETR) para as rochas carbonáticas do Grupo Bambuí, no sul da Bacia do São Francisco. Também são apresentadas idades U-Pb e isótopos de Hf em zircão detrítico e dados isotópicos de Sm-Nd em amostras de rocha total de rochas siliciclásticas no mesmo setor da bacia. Os dados quimioestratigráficos permitem dividir as três formações basais do Grupo Bambuí em três intervalos quimioestratigráficos (chemostratigraphic intervals - CI), cada qual registrando um estágio evolutivo da bacia. O CI-1 corresponde à capa carbonática da Formação Sete Lagoas que apresenta excursão isotópica negativa de C, valores de \'delta\'¹³C negativos e razões 87Sr/86Sr crescentes de 0,7074 a 0,7082. Este intervalo marca o início da transgressão marinha que inundou o Cráton do São Francisco onde a bacia estava sujeita a controles locais na química marinha, gerando carbonatos com padrões planares de distribuição normalizada de ETR e com variações acopladas de \'delta\'7Li e \'delta\'26Mg dependentes das fácies sedimentares. O intervalo CI-2 corresponde à porção intermediária da Formação Sete Lagoas na qual foi reportada a ocorrência de Cloudina sp. (550-542 Ma). As rochas carbonáticas deste intervalo apresentam valores de \'delta\'¹³C ao redor de 0%o, \'delta\'7Li ao redor de 16%o, \'delta\'26Mg de aproximadamente -3,5%o e razões 87Sr/86Sr entre 0,7080 e 0,7087, dentro do padrão esperado para o limite Ediacarano-Cambriano. Neste estágio, a transgressão marinha culminou com a conexão da Bacia do São Francisco com outras bacias gondwânicas, permitindo migração de fauna e homogeneização isotópica. Apesar de alguns sinais geoquímicos de caráter global, o cenário intracontinental da bacia a mantinha sujeita a controles locais, observados no enriquecimento de ETR leves em relação aos pesados e por duas excursões negativas nos valores de \'delta\'7Li perfeitamente acopladas a excursões positivas de\'delta\'26Mg. O intervalo CI-3 engloba as formações Sete Lagoas superior, Serra de Santa Helena e Lagoa do Jacaré e seus calcários com valores de \'delta\'¹³C bastante positivos (acima de +3%o) e razões 87Sr/86Sr ao redor de 0,7075, abaixo das esperadas para o limite Ediacarano-Cambriano. O CI-3 marca a restrição da bacia em relação ao reservatório geoquímico e isotópico global, provavelmente pelo soerguimento dos orógenos marginais ao cráton. Tal soerguimento provocou aumento da taxa de denudação e consequente decréscimo da intensidade de intemperismo nas áreas fontes, reduzindo o fluxo dissolvido para a bacia, observado no desacoplamento dos sistemas isotópicos de Mg e Li, e ciclos de decréscimo das razões Sr/Ca e 26Mg removidos pela precipitação carbonática. A diminuição da intensidade de intemperismo e a declividade das áreas fontes tornaram o fluxo dissolvido oriundo de carbonatos mais importantes que os de silicatos, resultando em diminuição das razões 87Sr/86Sr, no aparecimento de distribuições normalizadas de ETR com padrão \"água do mar\", na restrição do suprimento de sulfato na bacia e consequente metanogênese. Os dados geocronológicos mostram que não houve uma reorganização significativa nas áreas de fontes para a bacia desde a deposição das fácies mais finas da Formação Carrancas e Laminito Moema até a deposição da Lagoa do Jacaré. Embora não resolva as principais questões de idade e geotectônicas da bacia, esta constatação é mais um argumento a favor da ausência de uma discordância na base da Formação Sete Lagoas, o que sugere que a glaciação na base da Bacia do São Francisco é provavelmente do Ediacarano Médio / Superior. Se existir esta discordância, a única idade absoluta disponível para a capa carbonática sugere que a glaciação seria Sturtiana (~720 Ma). / This work presents new C, O, Sr, Mg and Li isotope data and Rare Earth Element (REE) concentrations for the carbonate rocks of the Bambuí Group, in the southern São Francisco Basin. U-Pb and Hf geochronology in detrital zircon grains and whole rock Sm-Nd ages in siliciclastic rocks in the same area are also presented. The chemostratigraphic data allow subdividing the three lower units of the Bambuí Group in three Chemostratigraphic Intervals (CI), each one recording a different evolution stage of the basin. The CI-1 comprises the Sete Lagoas Formation cap carbonates that display C isotope negative excursion, very negative \'delta\'¹³C values and 87Sr/86Sr ratios increasing upwards from 0.7074 to 0.7082. This intervals marks the start of the marine transgression over the São Francisco Craton in which the basin was subject to local controls over seawater, as shown by the flat type shale normalized REE distributions and coupled facies dependent \'delta\'Li and \'delta\'26Mg values variations. The CI-2 corresponds to the middle portion of the Sete Lagoas Formation where the Cloudina sp. (550-542 Ma) occurrence was described. The carbonate rocks of this interval display \'delta\'¹³C values around 0%o, \'delta\'7Li values around 16%o, \'delta\'26Mg around -3.5%o and 87Sr/86Sr between 0.7080 and 0.7087 that are expected for the Ediacaran-Cambrian limit. During this stage, the marine transgression provided connection of the São Francisco basin to other West Gondwana basins, allowing fauna migration and isotope homogenization. In spite of the global geochemical signals observed, the intracontinental scenario kept the basin subject to local controls, as shown by the enrichment in light REE and two perfectly coupled \'delta\'7Li and \'delta\'26Mg negative excursions. The CI-3 comprises the limestones of the upper Sete Lagoas, Serra de Santa Helena and Lagoa do Jacaré formations and with very positive \'delta\'¹³C values (> +3%o) and 87Sr/86Sr ratios around 0.7075, lower than those expected for the Ediacaran-Cambrian limit. The CI-3 records the restriction of the basin in relation to the global ocean geochemical and isotope reservoir, probably by the uplift of the craton\"s marginal orogens. Such uplift caused higher denudation rates and consequent decrease in the weathering intensity of the source areas, diminishing the dissolved influx to the basin that is observed in the Mg and Li isotope systems decouplement and in cycles of Sr/Ca ratios and 26Mg decrease by carbonate precipitation removal. The weathering intensity decrease caused the dissolved influx from carbonates to be more important than the one from silicates, resulting in the drop down of the 87Sr/86Sr ratios, the appearance of the \"seawater\" REE shale normalized distributions, and sulphate supply restriction driving methanogenesis. The geochronological data show that no significant reorganization of the basin source areas occurred from the deposition of the Carrancas Formation and Moema Laminites finer facies to the Lagoa do Jacaré Formation. Although the data do not solve the age and geotectonic questions, they add another argument against the existence of an unconformity at the base of the Sete Lagoas Formation, suggesting that the glaciation of the São Francisco Basin is likely Middle to Late Ediacaran in age. If there is an unconformity, the only available absolute age suggests it is a Sturtian Glaciation (~720 Ma).

A model study about the precise stratigraphy of the Kralodvorian Formation was made on the drill core from Ořech near Prague. The exposure at Levín was used as a reference section. Both sections were sedimentologicaly studied and described in detail. The study of thin sections was a supplemented for exact description of the rocks and lithotypes. Chemostratigraphic methods (?13C and TOC) and method of the rock magnetic susceptibility were used for detailed stratigraphic analyse. All the mentioned methods of both sections. Samples for the measurements of the magnetic susceptibility were taken by 0.5 m of thickness. The measurement of ?13C and TOC was taken from the non-wheathered 80 m of the drill core Ořech and from the upper 20 m Králův Dvůr Formation at Levín profile by 2 m. The available data show that Ořech represents low and middle part of the Kralodvorian strata and that all studied thickness (80 m) belongs to only positive excursion of ?13C. This excursion is interpreted to be the upper Katian. It gives an evidence that sedimentation of the Kralův Dvůr Formation was very fast. Identification and interpretation of this excursion makes possible the accurate interregional corelation of the strata. A precise regional stratigraphic subdivision is based on inhomogenities caused by different materials or...

The Bjursås ore field is located within the Bergslagen domain of central Sweden just northwest of the town of Falun. The field hosts small scale mines such as the 17th century Floberg copper mine and has been the focus of mineral exploration on several occasions during the 20th and early 21th century, with no major economic deposits being uncovered as of yet. Currently being explored by Boliden AB, this thesis focuses on alteration patterns in the southern part of the ore field, near the village of Oxberg. Several drill cores provided by Boliden AB have been logged and lithogeochemical samples were taken in intervals to aid in identifying alteration patterns and correlation.Three lithological and chemostratigraphic profiles have been created along a northeastern trend and show that the dominant lithologies are volcaniclastic silt- and sandstones with subordinate segments of pumiceous breccia-sandstones. They are primarily rhyolitic and dacitic. Pyritic argillite sediments belonging to the Oxberg formation occur sporadically and sub-intrusive and sills of amphibolites are common. Impure limestones with abundant quartz grains and limited lateral extents are encountered and suggest that high clastic input dominated during times favourable for limestone formation. The limestones do not host any major base metal mineralisation and coupled with limited lateral extents, do not appear to be a favourable future exploration target within the area.Two main alteration styles are recognised to be present in Oxberg. The first is an MgO-rich biotite-corderite-anthophyllite alteration and is associated with a weak to moderate impregnation of sphalerite and galena. The second is a FeO-rich biotite-garnet-staurolite-corderite alteration associated with magnetite-garnet-actionolite ± diopside skarn. No base metal sulphides are associated with the FeO-rich alteration. The MgO-rich style is interpreted be analogous to a metamorphosed VHMS-style hydrothermal system with a wider strong sericite-quartz alteration in the footwall and Mg-chlorite-rich near vent pipe alteration. The intercepted interval with MgO-rich alteration is located in an interpreted hinge zone of a fold in the Central profile and is interpreted to be a conduit feeder pipe for hydrothermally circulating fluids. Future drilling of this structure to learn the extent of the MgO-rich mineralised zone is recommended as it may lead to a massive sulphide lens.The Large box plot is demonstrated to be a useful tool for vectoring towards mineralisation in the area and may prove useful in future exploration of the area. Samples of sericite-quartz altered rock and MgO-rich alteration plot along trends on the Large box plot with MAI values that increase in the strongly altered sericite-quartz footwall rocks while CCPI values increase in the MgO-rich feeder zone that hosts base metal sulphides.Six chemical groups are identified around the Oxberg area. Of particular interest is the dacitic-andesitic chemical group, specifically siltstones, which display the strongest MgO-rich alteration. These are proposed to be a stratigraphic target interval for exploration and may lead to future base metal sulphide mineralisation in the area as well as the Bjurås ore field as a whole. / Bjursåsfältet ligger i Bergslagen strax nordväst om Falun. Vid Bjursåsfältet finns ett flertal hyttområden och mindre nedlagda gruvor, så som Flobergsgruvan som startades under 1600-talet. Området har varit i fokus för mineralprospektering vid flera tillfällen under 1900-talet och i början av 2000-talet men inga större mineraliseringar av ekonomiskt värde har hittats. Boliden AB undersöker för närvarande området och denna uppsats fokuserar på ett område inom Bjursåsfältet kring byn Oxberg. Omkring detta område har en stor omvandlingszon identifierats, men en detaljerad undersökning av denna zon har ännu inte gjorts. Mineraliseringar i berg beror ofta på att en fluid trängt igenom berget och av olika anledningar avsatt sitt metallinnehåll just där. Denna process leder vanligtvis också till att berget som fluiden trängt igenom omvandlas. En sådan omvandlingszon, som ofta är mycket större sett till volym än just själva mineraliseringen, kan agera som vägvisare för att nå fram till mineraliseringen.Borrkärnor som tidigare borrats inom detta område har karterats samt provtagits för kemisk analys med syfte att identifiera olika omvandlingsmönster och deras utbredning. Tre litologiska och kemiska tvärsnitt av underjorden har skapats utifrån borrkärnorna längs en nordöstlig trend. De visar att de dominerande bergarterna är utbrottsprodukter från olika vulkaner som var aktiva i området då bergarterna bildades. De är i första hand felsiska (ljusa bergarter, som exempelvis graniter) i sammansättning. Även lerrika sediment som tillhör Oxbergformationen förekommer sporadiskt och mafiska bergertar (mörka bergarter, som exempelvis basalt) samt orena kalkstenar förekommer i mindre utsträckning. Kalkstenar i Bergslagen är ofta associerade med mineralisering men detta verkar inte vara fallet kring Oxberg på grund av kalkstenarnas begränsade sidoutsträckning. Därmed föreslås kalksten inte vara ett gynnsamt mål för framtida prospektering i området.Två huvudsakliga omvandlingstyper är identifierade i Oxberg. Den första är en magnesiumrik biotit-corderit-antofyllit-omvandling som är associerad med en svag till måttlig impregnering av zinkblände och blyglans. Den andra är en järnrik biotit-granat-staurolit-corderit-omvandling i samband med magnetit-granat-aktinolit ± diopsid-omvandling. Inget zinkblände eller blyglans är förknippat med den järnrika omvandlingen. Den magnesiumrika omvandlingen gränsar till en bredare zon av stark sericit-kvarts-omvandling. Detta förhållande är utmärkande för en vis typ av malmbildningsprocess och en rekommendation är att titta närmare på just denna zon med hjälp av framtida borrningar.Utöver detta har två separata metoder identifierats vilka föreslås vara användbara för framtida prospektering av området. Metoderna baseras på kemisk provtagning av omvandlade bergarter och analysering enligt metoder beskrivna i denna uppsats.

No description available.

Important geochemical and tectonic events in the Paleoproterozoic Era lay the foundation for the status and operation of the modern Earth, including the initial rise of atmospheric oxygen paving the path for animal evolution, and the emergence of modern plate tectonic processes leading to the amalgamation of the Canadian Shield (Laurentia). Rudimentary geological and geochronological documentation of Paleoproterozoic sedimentary basins is the foundation from which we can ask larger questions about geochemical changes or plate tectonic events on the evolving Earth, since those questions are largely answered by analyzing the sedimentary record. This thesis outlines the stratigraphy, detrital zircon U-Pb geochronology, elemental and isotopic geochemistry, and basin evolution of the Paleoproterozoic Penrhyn and Piling basins on the Rae craton in Arctic Canada, which record important tectonic and geochemical events on both a regional and global scale. The concentration of the redox-sensitive trace element, U, in seawater has not been constant throughout geologic time and is linked to changes in oceanic and atmospheric oxygen content. Secular variations in the record of U contents of shales and iron formations indicate that the redox state of the atmosphere-ocean system after the Great Oxidation Event (GOE) was more dynamic than previously thought. Trends towards lower oxygen content recorded after ~2.05 Ga in the middle Proterozoic suggest that oxygen level decreased. This is contrary to traditional models assuming unidirectional atmospheric oxygen rise throughout the Proterozoic. The data demonstrate the earliest signal of oxidative U cycling, manifested in 2.47 - 2.43 Ga iron formations, and show that oxygenation was a protracted process initiated shortly after the end of the Archean. It has been proposed that a global and long-lived magmatic and tectonic shutdown event from ~2.45 to 2.22 Ga played a causal role in the GOE, since it overlaps the time interval in which atmospheric oxygen initially rose on Earth. Coupled U-Pb, Hf, and O isotope data on magmatic and detrital zircon determine that plate tectonic processes continued to operate during this interval. It is argued instead that plate tectonic processes are necessary to promote conditions favorable for atmospheric oxygen to rise.

Lors du Paléocène, le bassin d’avant-pays nord-pyrénéen est une large baie ouverte sur le proto-océan Atlantique. Ce golfe est constitué d’une plateforme carbonatée peu profonde dans la région des Petites-Pyrénées, et de sédiments majoritairement continentaux dans les Corbières (Aude). Nous avons recueilli des donnés sédimentologiques, au travers de 10 coupes, réparties sur un transect ouest-est d’environ 150 km, parallèle à l’actuelle chaîne des Pyrénées. L’analyse faciologique de ces coupes a permis de définir des séquences. L’absence de données stratigraphiques notamment dans les séries continentales des Corbières, rendait les corrélations incertaines. Ainsi pour améliorer le calage stratigraphique une analyse des variations du δ13Corg a été réalisée sur une coupe (Lairière)pour l’ensemble du Paléocène. Cette coupe a été comparée avec des coupes de références marines bien calées et ainsi ce travail a permis d’affiner la stratigraphie du Paléocène en domaine continental et plus largement dans la zone d’étude. Couplées à l’analyse séquentielle, ces données ont aussi permis de reconstituer l’architecture du Paléocène. Notre approche nous a permis de (1) tracer des esquisses paléogéographiques pour chacun des trois étages du Paléocène, de (2) proposer un modèle d’évolution tectono-stratigraphique et de (3) discuter des facteurs de contrôle de la sédimentation paléocène dans le bassin nord-pyrénéen. / During the Paleocene, the North Pyrenean Foreland Basin is an open bay on the Atlantic Ocean. This gulf consists of a shallow carbonate platform in the Petites-Pyrenees area, and mainly continental sediments in the Corbières area (Aude). We collected sedimentological data, through 10 sections, on a west-east transect of 150 km, parallel to the present-day Pyrenees. The facies analysis of these sections allowed us to define sequences but the lack of stratigraphical data, particularly in the continental deposits of the Corbières, made correlations uncertain. To overcome this problem, an analysis of the δ13Corg variations was carried out. It provided a geochemical curve for the whole Paleocene that was then compared with marine reference sections which made possible to refine the stratigraphy of the continental succession and more largely of the study area. Coupled with sequential analysis, these data have also enabled the reconstruction of Paleocene architecture. Our approach allowed us to (1) draw paleogeographic map for each of the Paleocene three stages, to (2) propose a model of tectono-stratigraphical evolution and to (3) discuss the control factors of Paleocene sedimentation in the North Pyrenean Basin