Este estudo teve como objetivo principal a definição da origem, evolução, geometria e preenchimento do Complexo de Canyons de Brejo Grande. Este complexo está incluído no intervalo maastrichtiano do Grupo Piaçabuçu, que é composto por uma cunha sedimentar progradante, depositada num sistema plataforma-talude-bacia, do Cretáceo Superior ao Quaternário, na Bacia de Sergipe-Alagoas. Foram utilizados dados sísmicos, perfis de poços, dados bioestratigráficos e descrições de testemunhos e amostras de calha. O complexo é composto de três canyons: Canyon de Brejo Grande, o mais antigo; Canyon do Rio Praúnas e Canyon de Aroeira, o mais novo. A localização e orientação dos canyons foram controladas por falhas da fase rift, reativadas antes da escavação. Foram reconhecidas quatro fases de preenchimento: fase inicial, fase de by-pass, fase dos complexos de canais e fase da cunha progradante. Na fase inicial, foram depositados os complexos de transporte de massa. Eles estão melhor preservados quando preenchem calhas na base do canyon. Na fase de by-pass o canyon atuou como um conduto e apenas depósitos de lags foram preservados. A fase dos complexos de canais ocorreu quando os fluxos gravitacionais não mais transportavam suas cargas para a bacia e depositavam a maior parte de sua carga dentro do canyon. A fase da cunha progradante corresponde à parte do preenchimento depositada no começo da subida do nível relativo do mar. Os complexos de canais são os componentes mais importantes do preenchimento dos canyons. Seus canais são frequentemente isolados espacialmente. Eventos sísmicos anômalos produzidos pelos canais mostram que eles são estreitos, com baixa sinuosidade e continuidade longitudinal variável. Os canais empilham-se verticalmente na parte inferior, mais confinada, do preenchimento dos canyons, e lateralmente na parte superior, menos confinada, dos canyons assimétricos. Os canais migram das partes mais confinadas para as menos confinadas. O método da estratigrafia de seqüências foi usado para estabelecer a evolução do complexo de canyons, definindo as seqüências que os preencheram, as relações de tempo entre aorigem e o preenchimento dos canyons e as superfícies limitantes e internas das seqüências. Foram definidas três seqüências de 3ª ordem. Cada canyon foi preenchido por uma seqüência deposicional composta pelos tratos de sistemas de mar baixo e transgressivo. Nos tratos de mar baixo das seqüências 1,2 e 3 foram identificados o equivalente proximal do leque de fundo de bacia e o complexo de canais do leque de talude. Na seqüência 3, além destes, foi também observada a cunha progradante. O limite inferior da seqüência 1 corresponde à base da biozona de nanofósseis N-280. O limite inferior da seqüência 2 coincide com a base da biozona de nanofósseis N-290. / Canyon The channels stack vertically in the lower, more confined portion of canyons, and laterally in the upper, less confined part of asymmetric canyons. Lateral migration of channels is from the side of steeper to the side of less steep wall, where confinement is smaller. The sequence stratigraphy method was used to establish the evolution of the canyon complex, defining the sequences that filled the canyons and the time relationship between the origin and filling of canyons and the boundary and internal surfaces of sequences. Three third order depositional sequences were defined. Each canyon is filled by a depositional sequence compounded of lowstand and transgressive system tracts. In the lowstand system tracts of the first, second and third sequences were identified a proximal equivalent of the basin floor fan andthe channel complexes of the slope fan. In the third sequence, besides those parts, was also observed the progradational wedge. The inferior limit of the first sequence corresponds to the N- 280 nannofossil biozone base and the inferior limit of the second sequence coincides with the N- 290 nannofossil biozone base.

Este estudo teve como objetivo principal a definição da origem, evolução, geometria e preenchimento do Complexo de Canyons de Brejo Grande. Este complexo está incluído no intervalo maastrichtiano do Grupo Piaçabuçu, que é composto por uma cunha sedimentar progradante, depositada num sistema plataforma-talude-bacia, do Cretáceo Superior ao Quaternário, na Bacia de Sergipe-Alagoas. Foram utilizados dados sísmicos, perfis de poços, dados bioestratigráficos e descrições de testemunhos e amostras de calha. O complexo é composto de três canyons: Canyon de Brejo Grande, o mais antigo; Canyon do Rio Praúnas e Canyon de Aroeira, o mais novo. A localização e orientação dos canyons foram controladas por falhas da fase rift, reativadas antes da escavação. Foram reconhecidas quatro fases de preenchimento: fase inicial, fase de by-pass, fase dos complexos de canais e fase da cunha progradante. Na fase inicial, foram depositados os complexos de transporte de massa. Eles estão melhor preservados quando preenchem calhas na base do canyon. Na fase de by-pass o canyon atuou como um conduto e apenas depósitos de lags foram preservados. A fase dos complexos de canais ocorreu quando os fluxos gravitacionais não mais transportavam suas cargas para a bacia e depositavam a maior parte de sua carga dentro do canyon. A fase da cunha progradante corresponde à parte do preenchimento depositada no começo da subida do nível relativo do mar. Os complexos de canais são os componentes mais importantes do preenchimento dos canyons. Seus canais são frequentemente isolados espacialmente. Eventos sísmicos anômalos produzidos pelos canais mostram que eles são estreitos, com baixa sinuosidade e continuidade longitudinal variável. Os canais empilham-se verticalmente na parte inferior, mais confinada, do preenchimento dos canyons, e lateralmente na parte superior, menos confinada, dos canyons assimétricos. Os canais migram das partes mais confinadas para as menos confinadas. O método da estratigrafia de seqüências foi usado para estabelecer a evolução do complexo de canyons, definindo as seqüências que os preencheram, as relações de tempo entre aorigem e o preenchimento dos canyons e as superfícies limitantes e internas das seqüências. Foram definidas três seqüências de 3ª ordem. Cada canyon foi preenchido por uma seqüência deposicional composta pelos tratos de sistemas de mar baixo e transgressivo. Nos tratos de mar baixo das seqüências 1,2 e 3 foram identificados o equivalente proximal do leque de fundo de bacia e o complexo de canais do leque de talude. Na seqüência 3, além destes, foi também observada a cunha progradante. O limite inferior da seqüência 1 corresponde à base da biozona de nanofósseis N-280. O limite inferior da seqüência 2 coincide com a base da biozona de nanofósseis N-290. / Canyon The channels stack vertically in the lower, more confined portion of canyons, and laterally in the upper, less confined part of asymmetric canyons. Lateral migration of channels is from the side of steeper to the side of less steep wall, where confinement is smaller. The sequence stratigraphy method was used to establish the evolution of the canyon complex, defining the sequences that filled the canyons and the time relationship between the origin and filling of canyons and the boundary and internal surfaces of sequences. Three third order depositional sequences were defined. Each canyon is filled by a depositional sequence compounded of lowstand and transgressive system tracts. In the lowstand system tracts of the first, second and third sequences were identified a proximal equivalent of the basin floor fan andthe channel complexes of the slope fan. In the third sequence, besides those parts, was also observed the progradational wedge. The inferior limit of the first sequence corresponds to the N- 280 nannofossil biozone base and the inferior limit of the second sequence coincides with the N- 290 nannofossil biozone base.

The aim of this study is to delineate the Campanian-Maastrichtian boundary by using planktonic foraminifers. In this manner, Kokaksu Section (Bartin, NW Anatolia) was selected and the Akveren Formation, characterized by a calciturbiditic-clayey limestone and marl intercalation of Campanian-Maastrichtian age, was examined. 59 samples were emphasized for position of boundary. Late Campanian-Maastrichtian planktonic foraminifers were studied in thin section and by washed samples. Two different biostratigraphical frameworks have been established. Globotruncanid zonation consists of Campanian Globotruncana aegyptiaca Zone, Upper Campanian-Middle Maastrichtian Gansserina gansseri Zone and Upper Maastrichtian Abathomphalus mayaroensis Zone, whereas heterohelicids biozonation includes Campanian Pseudotextularia elegans Zone, Lower Maastrichtian Planoglobulina acervuloinides Zone, Middle Maastrichtian Racemiguembelina fructicosa Zone and Upper Maastrichtian Pseudoguembelina hariensis Zone. Campanian-Maastrichtian boundary was determined as the boundary between Pseudotextularia elegans and Planoglobulina acervuloinides zones and Cretaceous-Tertiary boundary was designated by total disappearance of Late Cretaceous forms. Heterohelicid biozonation has been established in this study for the first time in Turkey. Collecting 300 individuals from each sample, diversity and abundance of assemblages were analyzed in terms of genus and species. ir evaluation of are important in observation of evolutionary trends and ecological changes. Moreover, evolution of different morphotypes is important in this evaluation. Such a study is new in Turkey in terms of examination of responses of planktonic foraminifers to environmental changes. Taxonomic framework has been constructed to define each species and differences of comparable forms have been discussed. Both scanning electron microscope (SEM) photographs and thin section photographs were used in order to show se distinctions.

Studies examining bioevents (e.g., mass extinctions, faunal turnovers, diversification events) usually only scrutinize a short interval prior to such events, however, understanding their actual paleobiological implications requires a thorough understanding of the background conditions. The objective of this study is to document the background biodiversity dynamics in a single lithofacies of the Upper Cretaceous Pierre Shale that was deposited in an offshore setting of the Western Interior Seaway (WIS) and to place these changes into an environmental context. To assess the background biodiversity dynamics, the concretionary faunas of the Baculites eliasi through B. clinolobatus biozones of the Pierre Shale in eastern Wyoming were examined to understand the structure of marine habitats in the WIS through an interval of ~2.5 Ma. Both changes in the taxonomic composition of assemblages and the relative abundance of the various species are interpreted to reflect ecological and environmental change through the study interval. The concretionary faunas are thought to represent relatively short-term, time-averaged accumulations of dead and living animals on the muddy sea floor of the WIS that were concentrated by storm or current activity. They are likely accurate representations of the original skeletonized fauna of the WIS. The samples with lower diversity and abundances show a relationship with intervals when water conditions were deepest and the paleoshoreline was furthest to the west, while higher diversity and abundances match periods when the paleoshoreline was the closest and shallow-water conditions prevailed in that part of the WIS. The decrease in diversity with depth can best be explained by the long-term presence of dysoxic/anoxic conditions that would have precluded benthic faunas. The distribution of taxa and diversity of the assemblages seen in the study interval most likely reflect migrating oxygen-controlled biofacies in the WIS that were responding to changes in depth and the proximity to the western shoreline that was in turn controlled by relative sea-level fluctuations. This analysis shows that significant changes in richness, abundance, and guild structure can arise in response to variations in sea level with no apparent changes in lithology. It is also shown that a lack of environmental context can significantly influence interpretations of paleobiological and paleoecological data and it is recommended that future lines of research should examine faunal, morphological, and ecological change in a time/environmental context.

Submitted by Silvana Teresinha Dornelles Studzinski (sstudzinski) on 2016-09-21T15:45:10Z No. of bitstreams: 1 Rodrigo do Monte Guerra_.pdf: 12842392 bytes, checksum: b6db9de51a65dd59c144edac22f16cab (MD5) / Made available in DSpace on 2016-09-21T15:45:10Z (GMT). No. of bitstreams: 1 Rodrigo do Monte Guerra_.pdf: 12842392 bytes, checksum: b6db9de51a65dd59c144edac22f16cab (MD5) Previous issue date: 2016-01-19 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Milton Valente / O final do período Cretáceo é caracterizado por uma gradual transição climática de escala global, fator que modificou a composição das assembleias de nanofósseis calcários e por conta disso vem causando problemas nas interpretações bioestratigráficas entre diferentes faixas latitudinais. Apesar de possuir alguns estudos realizados principalmente entre as décadas de 1980 e 1990, existe uma carência na avaliação do Atlântico Sul como um todo. Desta forma, este estudo objetiva descrever as assembleias de nanofósseis calcários comuns em cada faixa latitudinal e testar o sincronismo dos principais bioeventos. Foram analisadas 649 amostras provenientes de doze seções testemunhadas pelos projetos Deep Sea Drilling Project (DSDP) e Ocean Drilling Program (ODP) nas proximidades da margem brasileira e africana, além de um afloramento na Península Antártica. O estudo taxonômico possibilitou a identificação de 197 espécies de nanofósseis calcários do Campaniano e Maastrichtiano. Através do uso conjunto da bioestratigrafia e magnetoestratigrafia, foram reconhecidos diacronismos em eventos de primeira e última ocorrência de espécies do Campaniano superior e Maastrichtiano superior. Este diacronismo está relacionado a migrações de espécies entre baixas e médias latitudes, decorrentes de mudanças na circulação oceânica e temperatura das águas superficiais. Com base na variação latitudinal das assembleias de nanofósseis calcários, um detalhado estudo bioestratigráfico possibilitou a divisão de três zoneamentos para o Atlântico Sul (baixas, médias e altas latitudes). Além disso, foram definidos os padrões de distribuição de diversas espécies, mostrando uma clara divisão paleobiogeográfica entre espécies que ocorrem somente em latitudes altas e outras limitadas a latitudes médias a baixas. Este padrão possivelmente foi controlado por variações na temperatura das massas de água superficiais. Outras espécies possuem sua distribuição variada em todas as faixas latitudinais, tendo sua distribuição relacionada provavelmente à disponibilidade de nutrientes. / The Late Cretaceous period is characterized by global climatic transition that influenced calcareous nannofossil assemblages posing a challenge for biostratigraphic interpretation between different latitudinal degrees. There are a few studies on South Atlantic calcareous nannofossils from 1980 and 1990 decades, but none of them evaluate the South Atlantic as a whole. Therefore, this study aims to describe the calcareous nannofossils assemblages in each latitudinal zone and test the bioevents synchroneity. It were selected 649 samples from twelve cored sections coming from DSDP (Deep Sea Drilling Project) e ODP (Ocean Drilling Program) close to the Brazilian and African margins, in addition to an outcrop in the Antarctic Peninsula. The taxonomic study allowed the identification of 197 calcareous nannofossils species from the Campanian and Maastrichtian. Using the correlation between the biostratigraphical data and magnetostratigraphy, it was possible to identify diachronism in some bioevents of first and last occurrences during the late Campanian and late Maastrichtian. This diachronism is related to species migration between low and mid-latitudes, due to changes in the ocean circulation and surface water temperature. Based on the latitudinal variation in the calcareous nannofossils assemblages, a detailed biostratigraphic study enabled the South Atlantic division in three zonations (low, medium and high-latitudes). We also defined the distribution pattern of some species, indicating a clear paleobiogeographical division between high latitude species and some species limited to low and mid-latitudes. This pattern was possibly controlled by surface water temperature variation. Other species have a wide distribution across the latitudes probably related to nutrient availability.

No description available.

The Late Cretaceous–early Paleogene is the most recent period of Earth history with a dynamic carbon cycle that experienced sustained global greenhouse warmth and can offer a valuable insight into our anthropogenically-warmer future world. Yet, knowledge of ambient climate conditions and evolution of the carbon cycle at this time, along with their relation to forcing mechanisms, are still poorly constrained. In this thesis, I examine marine sediments recovered from the South Atlantic Walvis Ridge (ODP Site 1262) and Indian Ocean Ninetyeast Ridge (IODP Site U1443 and ODP Site 758), to shed new light on the evolution of the climate and carbon cycle from the Late Maastrichtian through to the Early Eocene (~67.10–52.35 Ma). The overarching aims of this thesis are: 1) to identify the long-term trends and principle forcing mechanisms driving the climate and carbon cycle during this time period, through construction of 14.75 million-year-long, orbital-resolution (~1.5–4 kyr), stratigraphically complete, benthic stable carbon (δ13Cbenthic) and oxygen (δ18Obenthic) isotope records; 2) to investigate in more detail the climatic and carbon-cycle perturbations of the Early–Middle Paleocene (e.g., the Dan-C2 event, Latest Danian Event and the Danian/Selandian Transition Event) and place these in their proper (orbital) temporal context; 3) to investigate the Late Maastrichtian warming event and its relationship to the eruption of the Deccan Traps Large Igneous Province, as well as its role (if any) in the subsequent Cretaceous/Paleogene (K/Pg) mass extinction; 4) to provide the first orbital-resolution estimates of temperature and carbonate chemistry variability from the low latitude Indian Ocean spanning the Late Paleocene–Early Eocene, through analysis of trace element and stable isotope data from multiple foraminiferal species. Taken together, the results presented in this thesis provide a critical new insight into the dynamic evolution of the climate and carbon cycle during the greenhouse world of the early Paleogene, and shed light on the potential forcing mechanisms driving the climate and carbon cycle during this time.

Les différentes lithologies sédimentaires du Groupe Belqa présentent un enrichissement en P et en toute une série d'éléments sensibles aux conditions redox. Il est montré que l'enrichissement en U, Cu, Co, Mo, V résulte d'un dépôt syn-sédimentaire sous conditions suboxiques. Par contre, les éléments Cr, Ni, Cd, Zn sont beaucoup plus enrichis et requierent un flux exogénique de métal probablement relié à l'altération de roches ultrabasiques obductées à la même période au nord de cette région, lors de la collision de la plaque arabo-africaine avec la plaque eurasienne. Les phosphates représentent le principal hôte de l'uranium et des terres rares. L'analyse des apatites par ablation laser ICP-MS a permis de montrer leur évolution, depuis le stade sédimentaire-diagénétique, puis pyrométamorphique, jusqu'à l'altération supergène. La libération de l'uranium de la structure de l'apatite lors du pyrométamorphisme et de l'altération supergène permet sa mise à disposition pour la formation de minéralisations. Le pyrométamorphisme, dû à une combustion des niveaux riches en matière organique, est responsable de la déstabilisation des apatites, et de la formation de roches de compositions semblables à des ciments clinker/Portland. L'uranium a également été libéré de la structure de l'apatite par altération supergène. L'altération météorique et les fluides évaporitiques ont permis le lessivage et le transport des éléments (U, V) des roches carbonatées métamorphiques, et des carbonates puis a conduit au dépôt des vanadates d'uranyles dans les carbonates pulvérulents ayant subi une dissolution importante / The different lithologies of the Belqa Group present an enrichment in P and various redox sensitive elements. The U, Cu, Co, Mo, V enrichment results from synsedimentary deposition in suboxic conditions. However, the higher Cr, Ni, Cd, Zn enrichment requires an exogenic metal flux probably related to the terrestrial leaching of ultrabasic rocks obducted during the collision between African-Arabian and Eurasian plates to the north of the study region, at the same time. Phosphates are the main host lithology for uranium and rare earth elements. The analysis of the apatites by laser ablation ICP-MS shows their evolution along the sedimentary-diagenetic and pyrometamorphic stages, up to the supergene weathering. The uranium liberation from the apatite structure during the pyrometamorphism and surficial weathering led to its availability as supergene ore mineralization. Pyrometamorphism resulted from the combustion of organic-rich layers and caused the destabilization of the apatites, and the formation of rocks which have compositions similar to clinker/Portland cements. Uranium has been also released from the structure of the apatite by supergene alteration. Meteoric weathering and the evaporitic groundwater resulted in the leaching and the transport of the elements (U, V) from the metamorphic carbonated hills, and from the surrounding permeable limestone which has undergone dissolution in the near surface zone

As part of the wider European GTS Next project, I propose new constraints on the ages of the Late Cretaceous, derived from a multitude of geochronological techniques, and successful stratigraphic interpretations from Canada and Japan. In the Western Canada Sedimentary Basin, we propose a new constraint on the age of the K/Pg boundary in the Red Deer River section (Alberta, Canada). We were able to cyclostratigraphically tune sediments in a non-marine, fluvial environment utilising high-resolution proxy records suggesting a 11-12 precession related cyclicity. Assuming the 40Ar/39Ar method is inter-calibrated with the cyclostratigraphy, the apparent age for C29r suggests that the K/Pg boundary falls between eccentricity maxima and minima, yielding an age of the C29r between 65.89 ± 0.08 and 66.30 ± 0.08 Ma. Assuming that the bundle containing the coal horizon represents a precession cycle, the K/Pg boundary is within the analytical uncertainty of the youngest zircon population achieving a revised age for the K/Pg boundary as 65.75 ± 0.06 Ma. The Campanian - Maastrichtian boundary is preserved in the sedimentary succession of the Horseshoe Canyon Formation and has been placed ~8 m below Coal nr. 10. Cyclostratigraphic studies show that the formation of these depositional sequences (alternations) of all scales are influenced directly by sea-level changes due to precession but more dominated by eccentricity cycles proved in the cyclostratigraphic framework and is mainly controlled by sand horizons, which have been related by autocyclicity in a dynamic sedimentary setting. Our work shows that the Campanian - Maastrichtian boundary in the Western Canada Sedimentary Basin coincides with ~2.5 eccentricity cycles above the youngest zircon age population at the bottom of the section and ~4.9 Myr before the Cretaceous - Palaeogene boundary (K/Pg), and thus corresponds to an absolute age of 70.65 ± 0.09 Ma producing an ~1.4 Myr younger age than recent published ages. Finally, using advances with terrestrial carbon isotope and planktonic foraminifera records within central Hokkaido, Northwest Pacific, sections from the Cretaceous Yezo group were correlated to that of European and North American counterparts. Datable ash layers throughout the Kotanbetsu and Shumarinai section were analysed using both 40Ar/39Ar and U-Pb methods. We successfully dated two ash tuff layers falling either side of the Turonian - Coniacian boundary, yielding an age range for the boundary between 89.31 ± 0.11 Ma and 89.57 ± 0.11 Ma or a boundary age of 89.44 ± 0.24 Ma. Combining these U-Pb ages with recent published ages we are able to reduce the age limit once more and propose an age for the Turonian - Coniacian boundary as 89.62 ± 0.04 Ma.

Dans le cadre du projet Européen GTS Next, nous avons obtenu des nouvelles contraintes sur l’âge des étages du Crétacé Supérieur à partir de plusieurs techniques de géochronologie et d’interprétations stratigraphiques au Canada et au Japon. Dans le bassin sédimentaire du Western Interior Canada, nous proposons une nouvelle détermination de l’âge de la limite Crétacé - Tertiaire (K/Pg) enregistrée dans la coupe de Red Deer River (Alberta). Il a été possible de calibrer par cyclostratigraphie haute-résolution cette série sédimentaire fluviatile non-marine et d’identifier 11-12 cycles associés à la précession orbitale de la Terre. En considérant la technique 40Ar/39Ar intercalibrée avec la cyclostratigraphie, l’âge apparent de la base du chron magnétique C29r suggère que la limite K/Pg se trouve entre un minimum et un maximum de l’excentricité, avec une durée pour C29r de 66.30 ± 0.08 à 65.89 ± 0.08 Ma. En supposant que le cycle contenant le niveau de charbon soit associé à un cycle de précession, l’âge révisé de la limite Crétacé - Tertiaire est donné par la plus jeune des populations de zircon datée par U-Pb à 65.75 ± 0.06 Ma.La limite Campanien – Maastrichtien est également enregistrée dans ce même bassin canadien, et se trouve à environ 8 m sous le niveau de charbon No. 10 dans la formation de Horseshoe Canyon. L’étude cyclostratigraphique montre que le dépôt de cette séquence sédimentaire est directement influencé par les changements du niveau marin dû à la précession et dominés par l’excentricité Notre travail montre que la position de la limite Campanien – Maastrichtien dans ce bassin sédimentaire du Western Canada est placée à environ 2.5 cycles d’excentricité au dessus d’un niveau de téphra de la base de la coupe dont l’âge U-Pb est donné par la plus jeune population des zircons, et ~4.9 Myr avant la limite Crétacé - Tertiaire. Nous en déduisons un âge absolu de 70.65 ± 0.09 Ma pour la limite Campanien – Maastrichtien, ce qui est ~1.4 Myr plus jeune que les études récemment publiées.Enfin, à partir des isotopes du carbone et des foraminifères planctoniques enregistrés au centre d’Hokkaido (Pacifique Nord-Ouest), les coupes Crétacé du groupe Yezo ont été corrélée avec les séries européennes et nord-américaines. Plusieurs niveaux de téphra prélevés au sein des coupes de Kotanbetsu et Shumarinai ont été datés par les méthodes 40Ar/39Ar and U-Pb. Deux d’entre eux, placés de part et d’autre de la limite Turonien – Coniacien, ont donné des âges de 89.31 ± 0.11 et 89.57 ± 0.11 Ma, ce qui suggère un âge de 89.44 ± 0.24 Ma pour cette limite. En combinant notre résultat avec les âges récemment publiés, nous pouvons proposer un âge de 89.62 ± 0.04 Ma pour la limite Turonien – Coniacien. / As part of the wider European GTS Next project, I propose new constraints on the ages of the Late Cretaceous, derived from a multitude of geochronological techniques, and successful stratigraphic interpretations from Canada and Japan. In the Western Canada Sedimentary Basin, we propose a new constraint on the age of the K/Pg boundary in the Red Deer River section (Alberta, Canada). We were able to cyclostratigraphically tune sediments in a non-marine, fluvial environment utilising high-resolution proxy records suggesting a 11-12 precession related cyclicity. Assuming the 40Ar/39Ar method is inter-calibrated with the cyclostratigraphy, the apparent age for C29r suggests that the K/Pg boundary falls between eccentricity maxima and minima, yielding an age of the C29r between 65.89 ± 0.08 and 66.30 ± 0.08 Ma. Assuming that the bundle containing the coal horizon represents a precession cycle, the K/Pg boundary is within the analytical uncertainty of the youngest zircon population achieving a revised age for the K/Pg boundary as 65.75 ± 0.06 Ma. The Campanian - Maastrichtian boundary is preserved in the sedimentary succession of the Horseshoe Canyon Formation and has been placed ~8 m below Coal nr. 10. Cyclostratigraphic studies show that the formation of these depositional sequences (alternations) of all scales are influenced directly by sea-level changes due to precession but more dominated by eccentricity cycles proved in the cyclostratigraphic framework and is mainly controlled by sand horizons, which have been related by autocyclicity in a dynamic sedimentary setting. Our work shows that the Campanian - Maastrichtian boundary in the Western Canada Sedimentary Basin coincides with ~2.5 eccentricity cycles above the youngest zircon age population at the bottom of the section and ~4.9 Myr before the Cretaceous - Palaeogene boundary (K/Pg), and thus corresponds to an absolute age of 70.65 ± 0.09 Ma producing an ~1.4 Myr younger age than recent published ages. Finally, using advances with terrestrial carbon isotope and planktonic foraminifera records within central Hokkaido, Northwest Pacific, sections from the Cretaceous Yezo group were correlated to that of European and North American counterparts. Datable ash layers throughout the Kotanbetsu and Shumarinai section were analysed using both 40Ar/39Ar and U-Pb methods. We successfully dated two ash tuff layers falling either side of the Turonian - Coniacian boundary, yielding an age range for the boundary between 89.31 ± 0.11 Ma and 89.57 ± 0.11 Ma or a boundary age of 89.44 ± 0.24 Ma. Combining these U-Pb ages with recent published ages we are able to reduce the age limit once more and propose an age for the Turonian - Coniacian boundary as 89.62 ± 0.04 Ma.