This PhD thesis is a commentary to the attached publications. The thesis deals with two microfossil groups Ostracoda and Foraminifera in the Upper Cretaceous of the Bohemian Cretaceous Basin. Contribution of these microfossils for biostratigraphy and application in palaeoenvironmental reconstruction with the modern approach is the main goal of this work. Basic ecology, biogeography and previous work in the Bohemian Cretaceous Basin is included. Studied fossil sites, methods, microfossil preservation and data evaluation are described below. Obtained palaeontological, geochemical and lithological data are interpreted in the context with available data from studied fossil sites. Ostracoda assemblage from Úpohlavy fossil site is correlated with the Ostracoda assemblage from Great Britain. The similarity of the Ostracoda taxa suggests a possible communication of compared areas. Thanks to this work, biostratigraphy occurrence of six Ostracoda species (Cythereloidea stricta, Nemoceratina (Pariceratina) montuosa, Cythereis ornatissima ornatissima, Phodeucythere cuneiformis, Pterygocythereis robusta a Bairdoppilata litorea) is extended to Upper Turonian. Taxonomical changes in studied ostracoda assemblage expressed by PSH hypothesis (Platycopid Signal Hypothesis) support previous palaeoenvironmental...

>Magister Scientiae - MSc / Southern offshore basins of South Africa are well known as potential provinces of hydrocarbon exploration and production. The complex nature of the Bredasdorp sub-basin’s syn-rift architecture (transform fault system) can have adverse effects on reservoir distribution due to periodic local and regional uplift of horsts and grabens. This present investigation focusses on an integrated approach of the 1AT1-V horizon or early Cretaceous sediments in the Bredasdorp sub-basin to identify the depositional environment and provenance of these sediments as well as their role in regionally complex compositional heterogeneities associated with the late stage rifting of Gondwana break-up. An integrated seismic, sedimentological (including petrography and geochemistry) and ichnologic analysis of the 1AT1-V horizon sediments showed an overall lower regressive element complex assemblage set and an upper transgressive element complex assemblage set that occurred as a >120m thick succession. The analysis identified a mixed-energy deltaic succession followed by an estuarine succession. The 1AT1-V interval (late syn-rift) consisted of nine sedimentary facies associations (and associated petrofacies) on a dipslope setting with variations occurring along the strike and the downdip depositional slope areas. Two overall sequences were identified as a lower regressive and upper transgressive sequence (Element complex assemblage sets). The regressive sequence consisted of middle to distal delta front lobe fringes, hyperpycnal event beds (sourced from basement highs), offshore migrating tidal bars (and associated inter-bar regions), distal mouth bars, terminal distributary channels (and associated inter-terminal distributary regions). The distal delta plain to proximal delta front consisted of interdistributary bays, distributary channels, crevasse splay sub-deltas, mouth bars, tidal flats and offshore embayments. In the laterally isolated depocenter, these deposits also consisted of basement high slopes with upliftment of the basement highs leading to proximal/central embayment to regressive shoreface/foreshore environments. These sequences consisted generally of low diversity and intensities (impoverished abundances) of trace fossils. The paleoclimate inference from this sequence indicates a humid climate with intermediate degrees of weathering intensities (possibly fluctuating arid-humid conditions). The transgressive sequence consisted of estuarine sedimentation with the occurrence of tidal sand ridges and compound dune fields, embayment facies and tidal bars. These sequences consisted of relatively higher ichnodiversities and intensities than their relative regressive sequences. The paleoclimate inference during these times consisted of more arid to semi-arid settings with low degrees of weathering in the source terrain. Local tectonic upliftment and subsidence, with exposed basement highs, gave rise to differential process regimes (tidal, wave and fluvial) and hence depositional facies in the diachronous updip/downdip areas (spatial) and within-stratigraphic (temporal) variations. There are several modern analogues that are similar to the 1AT1-V horizon sequence and they are the Mahakam, Ganges-Brahmaputra, Po, Burdekin deltaic and Satpara lake environments Compaction and dissolution diagenetic features as well as transportation were responsible for the major compositional heterogeneities concerning the reservoir quality and distribution. Proximal and distal sources were identified with first cycle and polycyclic sediments being deposited in the northern and southern part of the basin during the late stages of rifting in the Bredasdorp sub-basin. The provenance lithology has been identified as recycled sedimentary rocks (and their meta-equivalents) with an ultimate source terrain that was largely felsic in nature (Cape granite suite). The northern part of the studied section is suggested to have received sediments from the main metasedimentary rocks of the Cape fold belt (including the Table Mountain Group and Bokkeveld Group) whereas the southern sections received more sediments from the basement highs (recycled Malmesbury Group (and Pre-Cape sediments) and Cape granite suite), which is further supported by seismic data. Provenance analysis revealed that the Cape Fold belt (most recent collision) was possibly a provenance terrain but overprinting of several collisions are also acknowledged. The tectonic setting was envisaged to be of a rifted margin during the break-up of Gondwana. This compositional heterogeneity due to facies and provenance-related terrains had major consequences to the reservoir quality and distribution from the northern part to the southern part of the studied section

La marge active Est Gondwanienne s'est développée dans un contexte de subduction de type andine entre le Permien et le Crétacé inférieur. Suite à une période de rifting régional au Crétacé supérieur, qui précède l'océanisation de la Mer de Tasman, le continent Zealandia se détache du Gondwana. A l'Eocène, un événement tectonique majeur entraine l'obduction de matériel mantellique sur la marge Nord-Est du continent Zealandia, qui affleure aujourd'hui en Nouvelle-Calédonie (NC). L’enregistrement de ces événements tectoniques est accessible dans les bassins Ouest calédoniens dans lesquels d’épaisses séries sédimentaires se sont déposées. La longue période de subduction Phanérozoïque est principalement enregistrée par le dépôt de séries de turbidites volcanoclastiques (« grauwackes ») tandis que les périodes de rifting et de post-rift sont associées au dépôt de formations fluvio-deltaïques passant latéralement à des dépôts turbiditiques. La période pré/ syn-obduction, encore mal comprise et complexe, s’enregistre par une épaisse série gravitaire syn-tectonique (« Flysch ») sur laquelle reposent des formations mixtes silici-carbonatées en contexte récifal et lagunaire à terre, et turbiditique en mer. Ces séries sédimentaires sont aujourd’hui relativement bien cartographiées et identifiées à terre, mais leur étude détaillée d’un point vue sédimentologique fait toujours défaut. L’analyse de la carotte du puits onshore Cadart-1 qui échantillonne 1950 m des séries syn-rift à syn-obduction et des nombreux affleurements de la côte Ouest de la Grande Terre permettra d’apporter de nouveaux éléments sur les faciès, les géométries et les architectures de ces différentes séries. Aussi, une approche terre-mer est proposée en s’appuyant sur la nouvelle carotte IODP 371 U1507 et sur le nouveau jeu de données sismiques de la campagne TECTA acquis dans le Bassin de Nouvelle-Calédonie. L’objectif principal est d’améliorer la connaissance de l’histoire tectonique et sédimentaire de la Nouvelle-Calédonie à partir des enregistrements sédimentaires des bassins ouest-calédoniens, d’en déduire leur évolution paléogéographique en lien avec l’histoire géodynamique régionale. Sur un plan plus fondamental cette étude apportera des nouveaux éléments permettant de mieux comprendre les mécanismes de l’obduction. D’un point de vue appliqué, ce travail permettra également d’apporter des informations essentielles sur les potentielles roches mères, réservoirs et couvertures du système pétrolier des bassins de la Nouvelle-Calédonie. / From Permian to Early Cretaceous the eastern Gondwana margin was an Andine subduction context. Late Cretaceous widespread regional rifting affects this region and precedes Cretaceous to Eocene seafloor spreading of the Tasman Sea, leading to the isolation of the Zealandia continent. During the Eocene, a major tectonic event affects the entire region and leads to the obduction of mantellic material on the northeastern margin of Zealandia, which presently outcrops in New-Caledonia. The stratigraphic records of these tectonics events are accessible within the western New-Caledonian basins, in which very thick sedimentary series were deposited and are now visible through onland outcrops. The Phanerozoic eastern Gondwana subduction episode is recorded by volcanoclastic turbidites whereas rifting and post-rift phases are associated with fluvial-estuarian deposits capped by deeper deposits. The complex pre to syn-obduction phase is recorded by a very thick syntectonic gravity flow unit (“Flysch”), composed of turbidites originating from various siliciclastic and carbanoceous sources. These sedimentary series are well mapped and identified in New-Caledonia, but a detailed sedimentological description and interpretation is still lacking. Core descriptions from the CADART well which recovered 1930 meter of “flysch” series, combined with outcrop descriptions should bring new insight onto the sedimentary facies, geometries and stratigraphic architecture of these series. Following this, we focused on newly acquired data in the New Caledonian Basin, including new multichannel seismic data acquired during the TECTA cruise as well as new drilling data performed in 2017 during IODP Expedition 371. The main objective of this study is to improve the knowledge of the tectonic history of New Caledonia, from these sedimentary records. On a fundamental aspect, this study will allow to better understand the obduction mechanisms. In addition, this study should provide new information on the potential petroleum system of New-Caledonian basins.

No description available.

No description available.

The Starkville Quadrangle is a hotspot for geological research. The Late Cretaceous is represented by the Demopolis Formation in the northeast corner of the quadrangle, followed by the Ripley Formation, and the Prairie Bluff Formation. The K-Pg boundary is exposed in the quadrangle, and the remarkable paleontology is of global importance. The Clayton Formation is the first Paleocene unit. Where the Clayton Formation channel sands are in contact with the underlying Prairie Bluff Formation, springs occur. Springs were a rare source of water in the Black Prairie and spurred the settlement of the area over 10,000 years ago. The Paleocene Porters Creek Formation occurs in the southwest corner of the Quadrangle. Quaternary streams left Holocene to Pleistocene alluvium and terraces overlying the subcrop. This project provides a modern geologic map and stratigraphic framework as a background for future research in the Starkville Quadrangle.

<p> The Wapiabi-Belly River transition and the Belly River Formation was studied in detail in seven sections in the Ghost Dam spillway, near Ghost Dam,Alberta. Units in the lowest portion of the outcrop (Wapiabi) are characterized by sandy mudstones, often coarsening upwards. The mudstones are overlain by storm generated, hummocky cross-stratified sandstones and beach deposits. The vertical sequence represents a shallowing trend. </p> <p> Above the beach deposits lie sandstone and interbedded mudstone-sandstone units (Belly River) deposited in a meandering river environment. Sandstones thicker than approximately two metres were deposited as point bars, show sedimentary structures representative of channels and often pinch out, or laterally interfinger with mudstone. Interbedded mudstone-sandstone units were formed during flood stances. These overbank deposits are classified as either proximal or distal components of the meandering river system. </p> <p> Several marine trace fossils, (Macaronichnus segregatis, Skolithos, Planolites, Chondrites, Teichichnus, and Ophiomorpha nodasa), found in the Belly River rocks suggest a minor marine influence on the river system. </p> <p> The river system is inferred to have been moderately to highly sinuous and comparable in discharge to the Humber and Credit Rivers (Ontario). </p> <p> Petrographic studies show that point bar sandstones are often characterized by fining upward trends and an upward increase in the proportion of carbonate cement. </p> <p> Distal overbank deposits are normally overlain by proximal overbank deposits which inturn are overlain by either point bars or distal overbank deposits. Point bar deposits may be overlain by either proximal or distal overbank. </p> / Thesis / Bachelor of Science (BSc)

<p> Macro-borings and other biogenic structures found in Ostrea glabra valves were examined using a dissecting microscope, SEM and X-radiography. Shells were collected from in situ and transported oyster beds of the Bearpaw-Horseshoe Canyon Formation transition (Upper Cretaceous) at Drumheller, Alberta. Emended diagnoses for Entobia, Talpina and Zapfella were proposed and systematic descriptions of these ichnogenera along with Oichnus were done. Repair blisters and partitions apparently formed by the oyster in response to irritations were also described and interpreted. It was confirmed that statistical analysis could differentiate between round holes drilled by naticids and muricids. It was possible to define fossil micro-environments on the basis of an interpretation of taphonomy and paleoecology considered within the sedimentary context.</p> / Thesis / Bachelor of Science (BSc)

Detailed geochemical analysis of the turbidite-associated shales of the Cretaceous Katafito Formation, Greece, reveals important details regarding the paleoenvironment, paleoproductivity, and regional tectonics of the Pindos Basin. The Katafito Formation was deposited along an active margin at the early onset of closure of the Tethys Sea in the Pindos sub-basin. While careful studies of the coarse clastic component of turbidites are common, this study consisted of a detailed geochemical characterization of the fine-grained portions, which helped reveal paleoenvironmental information about the basin. This study combined organic and inorganic geochemistry utilizing elemental, mineralogical, and organic chemical signatures from fine-grained turbidite-associated sediments across six regional outcrops; three in the Peloponnese region and three in the Eprius region of Greece. In addition, shales from two outcrops associated with shallow marine deposits were sampled from Crete in the absence of identified turbidite outcrops and were used as reference point for geochemical indicators. In total 117 shale samples were analyzed via X-ray florescence (XRF) for elemental quantification, X-ray powdered diffraction (XRPD) for quantitative phase analysis of the minerals present, and Rock-Eval Pyrolysis for organic quality and type. Chemical trends between northern and southern outcrops reveal details about the tectonics, climate, and ocean circulation of the Pindos sub-Basin during the Cretaceous. Potassium feldspar and plagioclase feldspar show distinct trends between northern and southern outcrops, with a relative decrease in plagioclase to the north despite the source terrain becoming more mafic toward the north. This decrease in plagioclase to the north could show that the mountains were more developed in the north during the Cretaceous, leading to a higher orographic effect and the resulting increase in precipitation rates and the associated increase in weathering rate. Geochemical proxies for paleo-oxygenation (U/Th, V/Cr, Authigenic uranium, and degree of pyritization) are similar in abundance between northern Pindos, southern Pindos, and Crete samples, but using a Kolmogorov-Smirnov test at the 99% confidence level, these proxies show that the northern part of the basin was more oxic than the south at the time of deposition. This is interpreted to show that although the Pindos Basin waters were still well-oxygenated and in communication across the study area, the early signs of tectonic constriction were beginning to be seen in the north during the Late Cretaceous. Most samples contain less than 0.5% total organic carbon (TOC) based on Rock-Eval analysis, with a median of 0.36% and IQR of 0.29-0.47%. This could be the result of either low primary productivity or efficient recycling of organic matter in oxic conditions. However, paleo-TOC indicators such as nickel enrichment suggest that total organic carbon was likely 2-3% higher at time of deposition, which, given the interpretation that waters were dominantly oxic, suggests high primary productivity rates at the time of deposition. The large discrepancy between original and preserved TOC is at least partially explained by the high thermal maturation of the samples (Tmax median of 591°C and IQR of 594-437°C), suggesting that hydrocarbons have been generated and migrated out of the shales. Lastly, based on elevated calcium carbonate concentrations measured in shale samples and common preservation of detrital carbonate grains in the associated turbidite sandstones, along with the regional prevalence of time-equivalent limestones preserved across much of Greece and the broader region, it is interpreted that the turbidites of the Katafito Formation were deposited basinward of a well-developed carbonate shelf, and that siliciclastics were efficiently transported across this shelf through well developed and focused transport fairways.

No description available.