Biogenic “oozes” are pelagic sediments that are composed of > 30% carbonate microfossils and are estimated to cover about 50% of the ocean floor, which accounts for about 67% of calcium carbonate in oceanic surface sediments worldwide. These deposits exhibit diverse assemblages of planktonic microfossils and contribute significantly to the overall sediment supply and function of Florida’s deep-water regions. However, the composition and distribution of biogenic sediment deposits along these regions remains poorly documented. Seafloor surface sediments have been collected in situ via Johnson- Sea-Link I submersible along four of Florida’s deep-water regions during a joint research cruise between Harbor Branch Oceanographic Institute (HBOI) and Florida Atlantic University (FAU). Sedimentological analyses of the taxonomy, species diversity, and sedimentation dynamics reveal a complex interconnected development system of Florida’s deep-water habitats. Results disclose characteristic microfossil assemblages of planktonic foraminiferal ooze off the South West Florida Shelf, a foraminiferal-pteropod ooze through the Straits of Florida, and pteropod ooze deposits off Florida’s east coast. The distribution of the biogenic ooze deposits is attributed to factors such as oceanographic surface production, surface and bottom currents, off-bank transport, and deep-water sediment drifts. The application of micropaleontology, sedimentology, and oceanography facilitate in characterizing the sediment supply to Florida’s deep-water regions. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2017. / FAU Electronic Theses and Dissertations Collection

Thesis (M.A.)--University of Texas at Austin, 1988. / Vita. Includes bibliographical references (leaves 116-124).

This study implies a survey of a somewhat unexplored Cambrian carbonate formation in the Argentine Precordillera (AP) located in western Argentina, close to the city of San José de Jáchal. The carbonate platform of the AP is a unique piece of the South American geology and is in this study partly surveyed and compared with the Stephen Formation of northern Canada, a middle Cambrian unit renowned for its contents of exceptionally well preserved soft bodied fossils named the Burgess Shale biota. The investigated formation consists of an olistolith among the several Los Túneles Olistoliths at the Western Precordillera. The olistolith originates from the Cambrian Period and lies embedded in younger material with an age and history up for debate by several paleontologists and biostratigraphers. Shallow investigations have shown that these rocks may have similar properties to rocks of the Stephen Formation. There are only a few known rock assemblages on Earth showing Burgess Shale-type (BST) preservation and if the Los Túneles Olistolith proves to possess BST preservation it would be of great substance for the geological researchers of Argentina. The olistolith has in this study been explored by gathering samples in field and dissolving them in acid to investigate possible fossil content. The aim is thus to ascertain whether or not the Los Túneles Olistolith may contain especially well preserved fossils. This is the first study ever made of the microfauna in a middle Cambrian unit in the whole of South America, and hence it will tell if further investigations would be of interest. This survey determines that the Los Túneles Olistolith actually consists of three olistoliths encased in matrix, do not contain BST preservation and that further studies are not probable to show otherwise. The fossil findings, such as Chancelloriidae Chancelloria, Hexactinellida Recticulosa and Mollusca Hyolitha establish that the three Los Túneles Olistoliths originate from middle Cambrian while the matrix surrounding the olistolith is determined to be of Devonian age. / Den här studien är den första undersökningen någonsin som fokuserar på mikrofauna i sedimentära avlagringar från mellersta kambrium i Sydamerika. Studien utreder en tidigare bara ytligt utforskad kalkstensformation i västra Argentina, nära staden San José de Jáchal, i den argentinska precordilleran. Formationen, med namnet Los Sombreros Formationen, innehåller olistoliter från kambrium som undersökts och jämförts med den välkända Stephen Formation från norra Kanada, en formation som är känd för att innehålla exceptionellt välbevarade mjukdelar av fossil, kallat the Burgess Shale Biota. Syftet med studien är att fastställa huruvida Los Túneles Olistoliterna har potential att innehålla välbevarade fossil samt att utreda ifall ytterligare undersökningar är av intresse eller ej.                       Studien fokuserar på vad som tidigare trotts vara en av olistoliterna bland Los Túneles Olistoliterna, som är en del av Los Sombreros Formationen, men som i denna studie visat sig egentligen vara tre olika olistoliter som avsatts intill varandra. Tidigare ytliga undersökningar har visat att dessa olistoliter skulle kunna innehålla liknande fossil som the Stephen Formation. Det finns bara ett fåtal platser i världen där så pass exceptionellt välbevarade fossil tidigare hittats och om Los Túneles Olistoliterna skulle visa sig vara ett nytt fynd skulle det vara av betydelse för den fortsatta geologiska forskningen i Argentina. Genom insamling av prover som upplösts i syra och sedan undersökts i mikroskop har slutsatsen dragits att Los Túneles Olistoliterna inte innehåller Burgess Shale Biota och att ytterligare undersökningar förmodligen inte kommer visa annorlunda resultat. Fossilfynden som har gjorts, så som Chancelloriidae Chancelloria, Hexactinellida Recticulosa och Mollusca Hyolitha fastställer att de tre Los Túneles Olistoliterna härstammar från mellersta kambrium medan omkringliggande material kommer från Devon. / Este estudio se enfoca en un área poco explorada de una formación que aloja olistolitos carbonaticos del Cámbrico y Ordovícico situado en la Precordillera de Argentina en el oeste del país, cerca de San José de Jáchal, Provincia de San Juan. La plataforma carbonatada de la precordillera es una parte única de la geología de Sudamérica y es en esta investigación parcialmente estudiada y comparada con la Formación Stephen en el norte de Canadá, una unidad del Cámbrico Medio famosa por su contenido de fósiles excepcionalmente bien preservados llamado the Burgess Shale biota.                       La investigación se ha enfocado en un olistolito entre los varios que aparecen en el sector Los Túneles en el norte de la Precordillera de San Juan, oeste de Argentina. De este olistolito sa ha recuperado macrofauna indicativa del período Cámbrico. Este olistolito está alojado en rocas clásticas cuya una edad que es todavía un tema de debate entre paleontólogos y bioestratigrafos. Investigaciones superficiales han mostrado que estas rocas pueden tener los mismos atributos que las rocas de la Formación Stephen. Solo hay unas pocas formaciones sedimentarias en la Tierra que mantienen preservación del tipo de Burgess Shale (BST) y si el olistolito de estudio de la sección de Los Túneles presenta preservación de BST va a tener gran importancia para la Geología de Argentina. El estudio ha incluido un muestreo de campo de varios olistolitos, posterior tratamiento químico (desagregación física y química de las calizas en ácido para investigar possible contenido de microfósiles), y finalmente”picking” bajo lupa binocular para rescatar micropiezas fósiles. El objetivo de este es comprobar si el olistolito de la sección de Los Túneles puede tener fósiles especialmente bien preservados. Este estudio es el primer estudio de la micro fauna del Cámbrico medio en el conjunto de Sudamérica y de ahí que lo indicará si estudios adicionales serían de interés.                       Este investigación determina que el olistolito en Los Túneles Olistolitos en realidad consiste en tres olistolitos encerrados en matriz, contiene fósiles sin una preservación BST y por tanto estudios adicionales no son requeridos para demostrar lo contrario. Los hallazgos fósiles, por ejemplo Chancelloriidae Chancelloria, Hexactinellida Recticulosa y Mollusca Hyolitha, establezca que los tres olistolitos de Los Túneles Olistolitos son de Cámbrico Medio y la matriz que rodea a los olistolitos de periódo Devónico.

Η εργασία αυτή στηρίζεται στα αποτελέσματα των μικροπαλαιοντολογικών αναλύσεων που πραγματοποιήθηκαν σε βενθονικά τρηματοφόρα σε δείγματα ιζήματος. Τα ιζήματα προέρχονται από πυρήνα που συλλέχθηκε από το Ανατολικό Κρητικό πέλαγος. Στα βάθη ιζήματος που επικεντρώνονται τα δείγματα έχουν παρατηρηθεί αλλαγές τόσο στην γεωχημεία των ιζημάτων, όσο και στο ποσοστό οργανικού άνθρακα. Σε αντίστοιχα βάθη στο Δυτικό Κρητικό πέλαγος είχε εντοπιστεί ο σαπροπηλός S2(Geraga et.al 2005). Ο S2 δεν εντοπίζεται συχνά στα ιζήματα των πυρήνων γι’ αυτό αναφέρεται και ως “σαπροπηλός φάντασμα”(ghost sapropel). Σκοπός της εργασίας είναι ο εντοπισμός και η εξέλιξη των παλαιοωκεανογραφιών συνθηκών που επικρατούσαν στον πυθμένα της περιοχής μελέτης για το χρονικό διάστημα μελέτης. / -

Thesis (Ph.D.) -- University of Adelaide, Dept. of Geology, 1963. / Typewritten.

The Northern Isles are strongly influenced by changes in the North Atlantic Ocean atmosphere system and, as they project northwards from the British Isles, provide an ideal geographical opportunity to study changing climatic gradients during the last glacial/interglacial transition along with the detection of regime shifts. Three proxies, diatoms, pollen, and micro-XRF sediment chemistry, have been employed to explore the nature and timing of environmental changes within the water columns and the wider catchments of Loch of Sabiston, Orkney, and Loch of Clumlie and Loch of Grimsetter, Shetland to better understand the nature and timing of environmental change within and among the island groups. The records are constrained by radiocarbon dating, supported by tephrochronology, and the Greenland ice core chronology to enable the comparison of the records produced by this study with previous research in the North Atlantic region. The diatom and lithological results from Loch of Sabiston suggest early deglaciation at c. 23,000 cal BP followed by gradual warming (GI-1e) punctuated by the cooling events coeval with GS-1 and GI-1b. However, the pollen record reflects a lagged response in the development from colonising cold tolerant vegetation to more temperate shrub and woodland communities. The Oracadian signal is dominated by the switching on and off of the accumulation of marl which serves as a supporting indicator of warmer conditions. The Shetland landscape appears to have been deglaciated later at c. 16,400 cal BP, but also has clear representation of GI-1e and the cooling events of GI-1b and GS-1. Both the Shetland and Orkney records record the dramatic cooling of the Younger Dryas but also suggest a two stage change from colder and drier to colder and wetter conditions before the onset of the Holocene. Shetland appears to have experienced less extreme climatic changes in comparison to Orkney despite being in the same present phytogeographical region. This is likely due to the former persisting in the arctic domain and the latter being closer to the latitudinal shifts in the warmer ocean circulation of the North Atlantic during the LGIT. Comparison of the three proxies demonstrates that they may differ by several hundred years in their response to dramatic climatic changes and, therefore, highlights the strength of multi-proxy approaches to reconstructing Quaternary environments. Combining proxies such as diatom and μ-XRF scanning techniques will provide a greater understanding of the processes occurring during environmental change in this region.

No description available.

No description available.

The Jurassic (Toarcian) Posidonienschiefer of southern Germany is famous for its well preserved vertebrate fossils and its high organic content. The majority of the Posidonienschiefer (10 meters thick in the study area) consists of the Bituminous Shale, a fossiliferous laminated illite claystone. Two thin (30-40 mm) clayey pyritic biomicrosparites, the Upper and Lower Schlacken, interrupt the Bituminous Shale. Geologists who have studied the Posidonienschiefer disagree about the exact nature of its depositional environment. The argument centers on the interpretation of an impoverished benthic fauna and whether or not the water column directly above the sediment-water interface was anoxic or normally oxygenated. Kauffman (1981) proposed that an algal/fungal mat located at or near the sediment/water interface marked the boundary between aerobic and anaerobic conditions during deposition. The purpose of my research was to investigate the geologic conditions during deposition and early diagenesis of the Bituminous Shale and the Schlacken and to search for evidence of microbial activity. A detailed petrologic investigation of these two lithologies found no evidence of an algal/fungal mat, but did reveal the important contribution of microbial activity in the formation of pyrite and calcite cement. The Bituminous Shale was deposited in a low-energy tropical seaway. The upper water-column supported a diverse marine fauna. The aerobic/anaerobic boundary in the water column may have been located several millimeters above the sediment/water interface. Pore waters of the ocean-floor mud were dysaerobic to anaerobic. Occasional oxygenation events allowed opportunistic benthic organisms to colonize the sea-floor. Compaction of the Bituminous Shale occured prior to cementation of original porosity. Framboidal pyrite was formed during sulfidic diagenesis under anaerobic, but open, sediment/pore water conditions. Euhedral pyrite formed later as communication between pores became restricted during sediment compaction. The skeletal grains of the Schlacken formed as a winnowed lag deposit of Bituminous Shale sediment. During the early stages of sulfidic diagenesis the winnowed beds were rapidly cemented in a concretion-like sheet. Early cementation preserved delicate algal spores and clay fabric. Fossil bacteria were discovered in the calcite cement of the Schlacken by modified petrographic techniques, and confirmed with the scanning electron microscope. Experiments in which live bacteria were gradually entrapped in halite produced a crystal fabric identical to that of the fossiliferous calcite cement of the Schlacken. The microbial production of bicarbonate and ammonia during sulfidic diagenesis played a significant role in altering local geochemical conditions in the Schlacken sediment and initiated the precipitation of calcite cements. Fossil bacteria in the cements of the Schlacken are direct evidence of the presence and entrapment of bacteria during cementation, but do not conclusively prove their active role in the formation of calcite. / text

Les modifications cristallines et les stigmates présents à la surface des artéfacts préhistoriques résultent de phénomènes physico-chimiques et mécaniques interdépendants. Une fois décryptés et leurs évolutions comprises, ils permettent d’assigner à l’objet une position stratigraphique génétique, un emplacement paléogéographique et une histoire post-génétique relative aux lieux de résidence successifs. Cette démarche pétroarchéologique dynamique, fondée sur une optimisation des techniques d’observation de la pétrographie, de la minéralogie, de la micropaléontologie et de la morphoscopie aux différentes échelles, est un outil simple de détermination des matériaux et de leurs origines, dont les limites ne sont que celles de l’expérience et des référentiels. L’altération des matériaux est utilisée pour dépasser la simple gîtologie de la formation géologique d’origine et ainsi aboutir à une gîtologie des formations superficielles relatives, au sein de laquelle l’espace et le temps différencient les silex. Un silex est dès lors inscrit dans un itinéraire qui lui est propre et qui permet de mieux appréhender les lieux et les modalités de prélèvement par les hommes. Le domaine géographique utilisé pour cette recherche est vaste et comprend une bonne partie de la moitié sud de la France ainsi que certaines régions du Maroc. Cette variété régionale renforce la fiabilité des méthodes de diagnose utilisées. Ce mémoire se veut outil de caractérisation, établi sur les propriétés d’enregistrement des changements paléoenvironnementaux lisibles sur et dans les silex. Cet effort participe à la mise en place d’un protocole commun de recherche sur les matières premières, dans le but d’impulser une véritable dynamique collective au sein de la communauté des préhistoriens. Nous participons ce faisant à la résolution de deux problèmes archéologiques essentiels :- en reconstituant l’itinéraire parcouru par le silex avant sa collecte par l’homme préhistorique, nous précisons grandement la provenance du mobilier lithique présent dans une unité archéologique ;- en décryptant l’intensité et la chronologie des mécanismes susceptibles d’avoir pris part à la sédimentogenèse et à la diagenèse des dépôts, nous participons à l’évaluation du degré d’intégrité de la zone fouillée.À l’issue de ce travail, nous disposons donc d’un outil de diagnose robuste, assorti de données cartographiques à une échelle suprarégionale et de fiches détaillées de caractérisation d’un très grand nombre de types de silex, tant pour le sud de la France que pour le centre-ouest du Maroc. / The characteristics of their initial crystallization and the evidence for subsequent alterations present on the surfaces of prehistoric flint artifacts are the result of a range of interdependent physical, chemical and mechanical phenomenas. Once decoded, the information retrieved allows us to assign a genetical/stratigraphical position to the flint as well as a post-genetic paleo-geographical location. Both data sets reveal the story ofan objects successive residential contexts. This petro-archaeological analytical methodology, is based on anoptimization of the optical techniques commonly used in petrography, mineralogy, micro-palaeontology and morphoscopy using a range of magnifications is a simple tool for classifying objects and identifying the source of lithic raw materials. The limitations of the methodology are determined by the experience of the operatorand the geographical spread of available reference collections. A study of the various alterations to which lithic raw materials were subjected and which are recorded within their surface characteristics allows connections to be made between the lithic objects and the surface exposures where these characteristics manifest in the lithics rather than just seeing the objects from a perspective that does not connect them with landscapes and specific resource localities. Thus, the methodology used here allows the comparison of flint objects within the context of time and space, and within which the genesis of each object can be followed, thus resulting in a greater understanding of where, why and how, it was collected during prehistory. The geographical extent in which this research has been undertaken is wide and includes parts of Moroccoand the southern part of France and has taken place within broad investigations into lithic raw materials being conducted by a number of members of a research team. A trial of the methodology over such a broad spectrum of site locations has allowed an improvement to be made in the reliability of the analytical techniques that are required. This work aims to aid in the characterization of the lithic tools as they describe and catalogue the properties of palaeo-environmental changes that can be read on the surface of the flint. The outcome of this work is that it produces a greater understanding of the many physical, geological and environmental processes to which lithic objects have been subjected both before gathering by humans and after discard in the archaeological site. This helps for a more precise location of gathering areas and a better evaluation of the archaeological layers integrity. These results are expressed on large scale maps and stored in an indexing system which catalogues the varied characteristics of a large number of types of flint found in the South of France and the west central region of Morocco.