Palynological analyses of 13 samples from two sediment cores retrieved from the Sabrina Coast, East Antarctica, provide the first information regarding the paleovegetation within the Aurora Subglacial Basin. The assemblages, hereafter referred to as the Sabrina Flora, are dominated by angiosperms, with complexes of Gambierina (G.) rudata and G. edwardsii representing 38–66% of the assemblage and an abundant and diverse Proteaceae component. The Sabrina Flora also includes Battenipollis sectilis, Forcipites sp. and Nothofagidites spp. (mostly belonging to the N. cf. rocaensis-flemingii complex), along with a few fern spores, including Laevigatosporites ovatus, a moderate presence of conifers, and previously undescribed morphospecies, two of which are described herein. A majority of the assemblage is interpreted as deposited contemporaneously with sedimentation, including Gambierina spp., which is traditionally assigned a Cretaceous–earliest Eocene age range. However, our age diagnosis for the Sabrina Flora, based on key morphospecies, indicates that sediment was most likely deposited between the latest Paleocene to possibly early–middle Eocene, if Gambierina rudata and G. edwardsii extended longer than previously thought. Additionally, we observed abundant dinoflagellate cysts of Campanian age. The absence of typical Paleocene–middle Eocene dinoflagellate cysts suggests that strata recovered were fluvial-dominated or proximal marine, with a major contribution of reworking of Campanian marine sediment. This study adds to the available East Antarctic palynological data and provides information on regional differences along the East Antarctic margin, as well as with southern Australia. The pollen diversity and the large relative abundance of Gambierina spp., along with the rarity of Nothofagidities spp., (fusca group), and the lack of megathermal elements (e.g., Arecaceae) separate the Sabrina Flora from those of other East Antarctic margin and southern Australian basin sites.

No description available.

The Monmouth and Brightseat Formations contain a rich and diverse dinoflagellate assemblage. Thirty-five genera and sixty-six species, of which two genera and eight species are new, are described in this study. The stratigraphic distribution of the taxa is summarized in Figure 4. The content of the assemblage changes suddenly at the Cretaceous-Tertiary boundary with thirteen species making the~r first appearance at or just above the boundary. Nineteen species cross the boundary and thirty-five species are restricted to the Cretaceous. The rather sudden change in the nature of the dinoflagellate assemblage at the boundary is interpreted by the author to indicate a paraconformable relationship between the Cretaceous and Paleocene sediments. The term paraconformity is used since there is little field evidence (a few pebbles, some lignite, and evidence of boring) indicating any extensive period of erosion at the boundary. / Master of Science

published_or_final_version / abstract / Earth Sciences / Master / Master of Philosophy

Submitted by Silvana Teresinha Dornelles Studzinski (sstudzinski) on 2016-09-16T12:36:44Z No. of bitstreams: 1 Guilherme Krahl_.pdf: 3540605 bytes, checksum: f897aa64ffa767d4eab27ec750818120 (MD5) / Made available in DSpace on 2016-09-16T12:36:44Z (GMT). No. of bitstreams: 1 Guilherme Krahl_.pdf: 3540605 bytes, checksum: f897aa64ffa767d4eab27ec750818120 (MD5) Previous issue date: 2016-07-29 / UNISINOS - Universidade do Vale do Rio dos Sinos / O Paleoceno caracteriza-se por um intervalo que sucede o evento de extinção em massa do K/Pg, o qual afetou diversos grupos fósseis. Seu estudo, portanto, revela não apenas padrões sequenciais de radiação evolutiva como processos relacionados à complexa recuperação dos ecossistemas marinhos. Devido a suas características ecológicas os foraminíferos planctônicos são uma importante ferramenta paleoceanográfica para a compreensão da evolução físico-química dos sistemas pelágicos, bem como da evolução do grupo ao longo do Paleoceno. Neste contexto, este trabalho objetiva a caracterização bioestratigráfica e paleoecologica com base em foraminíferos planctônicos paleógenos do testemunho DSDP Site 356 (Leg 39), localizado no Atlântico Sul ocidental. / The Paleocene is characterized by an interval that succeeds the K-Pg mass extinction event which affected several fossil groups. In its study reveals not only a sequential pattern of evolutionary radiation but also processes related to the complex recovery of marine ecosystems. Due to their ecological characteristics the planktonic foraminifera are an important paleoceanographic tool for the understanding of the physicochemical evolution of marine pelagic systems as well as the evolution of the group along the Paleocene. In this context, this paper aims to conduct a biostratigraphic and paleoecological analysis based on Paleogene planktonic foraminifera assemblages (Danian/Seladriano) from the DSDP Site 356 (Leg 39) drilled in the western South Atlantic.

The major purpose of this study was to examine in detail the anomalous transgressive "boundary" sandstones which generally are present at formation boundaries throughout the Parras and La Popa basins. These extensive sheet-like sandstone bodies are massive, resistant units up to 20 m thick and up to 25 km wide that form the cap of mountains and hogbacks. These are anomalous units because transgressive deposits thicker than 5-10 m are rare in ancient deposits although they are well-documented for some Holocene deposits. For example there are no known thick transgressive deposits in the well-studied cyclic transgressive-regressive sequences in the Cretaceous rocks of the Rocky Mountains. McBride and others (1975) previously interpreted these boundary sandstone bodies to have been laid down as thick transgressive or regressive blanket deposits as the shoreline moved back and forth across the basins in response to variable basin subsidence and sediment input. In order to clarify this interpretation, we selected deposits formed during the latest part of the first deltaic progradation represented by the Cerro Huerta Formation, and at the beginning of the first marine transgression represented by the Cañon del Tule Formation for detailed study. / text

This study focuses on the main depocenter of the Andrew Formation in the Moray Firth Basin, located at the junction of the Central and Viking Grabens, in the central North Sea. The objectives of this report are to (1) define the sequence stratigraphic framework of the Andrew Formation, (2) describe and characterize the depositional systems associated to the Andrew slope to basin system, and (3) interpret the depositional processes that have dominated sediment emplacement. Specific facies association of the Andrew Formation are determined by the nature (point source or linear source) and caliber (volume, grain size, sand:mud) of sediment supply to the slope environment. Genetic interpretation of the Andrew Formation focuses on understanding depositional processes which dominated sediment emplacement. Seven depositional facies have been identified for the Andrew slope and basinal system; turbidite channel-fills, turbidite lobes, mounded turbidite lobes, sheet turbidites, debris flows and slumps, low density turbidites and hemipelagic drapes. Seven depositional processes collectively create the above mentioned Andrew depositional facies; turbidity currents, cohesive mud flows, sandy debris flows, muddy debris flows, slumping, low density turbidity currents and suspension settling. The Andrew Formation consists of upper and lower depositional units identified on seismic by bounding downlap terminations and on well logs by high-gamma marker beds. The lower Andrew displays three distinct sand-rich lobes, delineated by isopach and sand percent maps and log motif characteristics. Proximal, mounded, sand-rich units disperse into unchannelized sheet turbidites in the basin plain areas. The upper Andrew downlaps the lower unit, and a single, linear sediment source was centered in the Witch Ground Graben. The sediment dispersal pattern and internal facies character suggest the upper unit is a proximal slope-apron downlapping and filling inter-lobe bathymetric lows of the underlying unit. The lower Andrew is interpreted to be a structurally focused, sand-rich lobe complex, without associated incised canyons. The Andrew system evolved as the delta platform expanded onto the proximal fan, resulting in a linear sediment source spilling over the slope as a fringing slope-apron. The Andrew depositional system in the slope and basin environment is characterized by a high degree of facies disorganization composed of a wide array of gravity-flow deposits. / text

No description available.

abstract: The Juglandaceae (walnuts, hickories, pecans) has one of the best-documented fossil records in the Northern Hemisphere. The oldest modern genus, Cyclocarya, today restricted to China, first appears in the late Paleocene (57 ma) of North Dakota, USA. Unlike walnuts and pecans that produce edible fruits dispersed by mammals, Cyclocarya fruits are small nutlets surrounded by a prominent circular wing, and are thought to be wind- or water-dispersed. The current study provides the first evidence that fossil fruits were different from modern forms in the number and organization of their attachment to reproductive branches, and in their anatomical structure. Unlike the modern genus that bears separate pistillate and staminate flowers the fossil fruits had attached pollen-bearing structures. Unisexual pollen catkins are also present, suggesting the fossil Cyclocarya may have differed from its modern relative in this feature. Like several other plants from the late Paleocene Almont/Beicegel Creek floras, Cyclocarya shows a mosaic combination of characters not seen in their modern counterparts. Fossils were collected from the field, and examined for specimens exposed on the weathered rock surface. Specimens from Almont were photographed with reflected light, while those from Beicegel Creek cut into slabs and prepared by etching the rock matrix in 49% hydrofluoric and re-embedding the exposed plant material in cellulose acetate and acetone to make "peels". Selected specimens are cut out, mounted on microscope slides, and studied with light microscopy. These fossil fruits were studied because they are the earliest fossil evidence of Cyclocarya. They are exceptionally preserved and thus provide critical structural evidence for changes in that occurred during the evolution of plants within this lineage. Because Cyclocarya fruits are winged, they might be assumed to be wind-dispersed. Their radial symmetry does not have the aerodynamic qualities typical of wind-dispersed fruits, and may have been dispersed by water. / Dissertation/Thesis / Ph.D. Plant Biology 2010

The Paleocene and early Eocene (~66–40 Ma) is characterised by a number of transient warming events, also named hyperthermals. A more recent candidate for a hyperthermal of Paleocene age is the Latest Danian Event (LDE, ~62.2 Ma). So far, the LDE was only poorly explored in few deep-sea records and Tethyan shelf settings. Planktic data characterizing the surface ocean were almost completely missing. In this thesis, it was studied whether the LDE satisfies the requirements for a hyperthermal and the impact on the planktic foraminfera fauna. Samples from three late Danian deep-sea cores (ODP Sites 1210 and 1262, IODP Site U1407) and one Tethyan shelf section (Qreiya 3, Egypt) were investigated in rather high resolution, which, for the first time, allowed to unravel the impact of the LDE, the evolution of the ocean structure and planktic foraminiferal species abundances on an almost global scale. δ18O paleothermometry revealed a temperature rise of 2–4°C affecting the entire water column in all three depth habitats (sea floor, subsurface and surface ocean) and a contemporary negative carbon isotope excusion of 0.6–0.9 ‰ indicates carbon cycle perturbations. Changes in the planktic foraminiferal assemblages indicate a global biotic response to the LDE.