Thesis (Ph. D.)--University of Wisconsin, 1967. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S.)--Brigham Young University. Dept. of Geology, 2005. / Includes bibliographical references (p. 15-19).

Thesis (Ph. D.)--M.I.T., Dept. of Earth and Planetary Sciences, 1979. / Supervised by S. Honjo. Bibliography: p. 110-119.

Η Μεσόγειος αντιπροσωπεύει µια από τις περιοχές “κλειδί” στις παλαιοωκεανογραφικές µελέτες από τη στιγµή που οι υδρογραφικές και ιζηµατογενείς διαδικασίες είναι ευαίσθητες στις κλιµατολογικές αλλαγές των παρακείµενων ηπείρων. Οι περισσότερες δηµοσιευµένες µελέτες εξέταζαν τις διαδικασίες που είναι υπεύθυνες για την απόθεση σαπροπηλών στην Ανατολική Μεσόγειο κατά τη διάρκεια του Πλειστοκαίνου. Η µελέτη αυτή βασίζεται στην µικροπαλαιοντολογική ανάλυση βενθονικών τρηµατοφόρων του πυρήνα ΤΙ13, ο οποίος συλλέχθηκε από το Ανατολικό Κρητικό Πέλαγος και υπάγεται στο βάθος απόθεσης του σαπριπηλού S1. / -

During the Austral Spring of 2007-2008 the ANtarctic geological DRILLing program (ANDRILL) recovered a 1,138 meter long sediment core AND-2A from the western side of the Victoria Land Basin for the Southern McMurdo Sound Project. The main goal of the project is to help establish a Neogene (~24 to 1.6 Mya) ice volume and climate record of Antarctica. This study focuses on the foraminifera record of AND-2A for paleoenvironmental and biostratigraphic purposes.AND-2A is unique in that it contains a Middle Miocene record (~17 to ~11 Mya) that includes the Middle Miocene transition of warm climatic conditions favoring polythermal ice sheets to major cooling into polar conditions resulting in the quasi-permanent formation of the East Antarctic Ice Sheet. This Middle Miocene transition has not been previously recovered from the Antarctic continental margin.The foraminifer record is not abundant; however, three assemblage zones are identified throughout AND-2A. Calcareous benthic taxa dominate every assemblage, as well as displaying similarities between modern shallow shelf assemblages around Antarctica and assemblages from previous drilling projects in the Ross Sea sector. The foraminifera record displays a dynamic environmental record and is supported by both the sedimentologic and other paleontologic findings.

Marine sediment samples were collected from Quebrada la Higuera, Chile to provide a record of planktonic and benthic foraminifera as a means of reconstructing the paleo-bathymetry and paleo-environment of the Quebrada la Higuera basin. The research area is located in northern Chile, south of Caldera in Quebrada la Higuera (S 27° 16.443, W 70° 54.887). The Quebrada la Higuera basin rests unconformably atop Mesozoic gabbroic basement, which is locally exposed, representing fault-bounded horsts and grabens. At the base of the section, diatomaceous sediment within the sequence suggests intervals of high productivity. The co-occurrence of the shallower water benthic species Nonionella miocenica and Epistominella pulchella with deep-water species Bolivina tumida, Uvigerina peregrina, Globobulimina auriculata, and Bolivina subfusiformis, at 10-23 m above the base of the section and again at 44-62 m, within fining-upward sedimentary packages suggests possible turbidites caused by transgressive-regressive cycles. Additionally, the occurrence and high abundance of these species are indicative of high productivity. A 30-40 cm Late Miocene phosphatic bed consisting of vertebrate and invertebrate fossils lies unconformably atop a poorly consolidated sand ~42 m from the base of the section. This phosphatic bed suggests that upwelling was occurring off the coast of Chile earlier than previously believed. The hyperaridity of Chile's Atacama Desert has been the result of the cold upwelling Peru-Chile current, which is further intensified by the rain-shadow effect of the Andes and the cold, dry descending Hadley cell. The occurrence of planktonic foraminifer Globigerina bulloides at the base of the section establishes the maximum possible lower age limit of 15.97 Ma (Middle Miocene). At 47 m, the co-occurrence of Globorotalia margaritae, Globorotalia crassaformis, and Dentogloboquadrina altispira establishes a maximum age limit for that horizon of ~3.6 Ma (Early Pliocene), providing an age range for the Quebrada la Higuera section from Middle Miocene through Early Pliocene. This study provides a record of planktonic and benthic foraminifera as a means of reconstructing the paleohistory of Quebrada la Higuera and more broadly through the Caldera region. The analyses address interactions between uplift, atmospheric conditions, sea level, and upwelling within the region from interpretations of the composite section, including facies relationship between sediments and occurring foraminifera species. These observations, along with the foraminiferal record, help broaden the understanding and development of the Quebrada la Higuera Neogene record.

Une étude des faunes de conodontes du Dévonien supérieur (Frasnien) a été réalisée sur deux coupes algériennes de la plate-forme occidentale du Sahara, Marhouma sud (bassin de l'Ougarta) et Ben Zireg (bassin de Béchar). Dans la coupe de Marhouma le Frasnien apparaît complet, tandis qu'une lacune du Frasnien inférieur est enregistrée à Ben Zireg. La limite entre les étages Frasnien et Famennien a été précisément localisée.Les corrélations entre ces coupes montrent une forte condensation des dépôts au Frasnien moyen à Ben Zireg, alors qu'au même moment d'épaisses séries argilo-carbonatées s'accumulent dans l'Ougarta. Au cours du Frasnien supérieur un changement de la structuration des bassins est constaté avec l'homogénéisation du taux d'accumulation dans les deux secteurs.Afin de reconstituer les environnements de dépôt du Frasnien, nous avons mené une étude multidisciplinaire basée sur la sédimentologie des faciès, la susceptibilité magnétique, les biofaciès à conodontes et les morphogroupes de foraminifères agglutinés. La combinaison de ces outils révèle qu'au cours du Frasnien, la plate-forme saharienne algérienne était assimilable à un domaine de rampe externe, carbonatée, de faible pente, avec des zones proximales dominées essentiellement par des communautés pélagiques, passant à des zones distales dominées par des faciès boueux et nodulaires à rares faunes. L'essentiel des dépôts était situé sous/ ou en limite de/ l'action des vagues de tempêtes.La coupe de Marhouma représente une coupe de référence pour l'étude des dépôts anoxiques du Frasnien. Certains de ces niveaux ont pu être rapportés à des événements anoxiques globaux tels que le Middlesex et le Rhinestreet, datés du Frasnien moyen, et le Kellwasser supérieur dans le Frasnien supérieur. Pour la coupe de Ben Zireg, seul le facies relatif aux Kellwasser inférieur et supérieur a été identifié.L'évolution temporelle de ces différents paramètres a permis également de proposer une courbe de variations du niveau marin pour la partie nord du Gondwana. À long terme, le Frasnien est caractérisé par une tendance transgressive entrecoupée de tendances régressives mineures. La fin du Frasnien est marquée une régression majeure lors de l'événement Kellwasser, avant la transgression du Famennien inférieur. / A study of the conodont faunas from the Upper Devonian (Frasnian) has been realised in two sections located on the Algerian Sahara platform: south Mahrouma (Ougarta basin) and Ben Zireg (Bechar Basin). At Mahrouma, the Frasnian seems to be complete, but the lower Frasnian is absent in Ben Zireg. The boundary between the Frasnian and the Famennian has been precisely located.The correlations between the two sections show a strong condensation of deposits during the middle Frasnian in Ben Zireg, whereas thick series of argilites and carbonates accumulated in the Ougarta basin. During the Upper Frasnian a change in dynamic basin structure is observed when accumulation rates become homogeneous in the two areas.In order to reconstitute Frasnian depositional environments, a multidisciplinary study based on sedimentology of the facies, magnetic susceptibility, conodont biofacies and morphogroup analysis of agglutinated foraminifera has been undertaken. The combination of these tools indicates that during the Frasnian, the algerian platform took part of a slightly inclined outer carbonated ramp domain. The proximal areas were essentially dominated by pelagic communities, the distal areas being dominated by muddy and nodular facies with rare faunas. The major part of the deposits was located under or at the limit of tempest wave action.The Mahrouma section represents a reference for investigations on Frasnian anoxic deposits. Some of its levels could have been related to global anoxic events such as the Middlesex and the Rhinestreet that are dated Middle Frasnian, as well as the Upper Kellwasser at the top of the Frasnian. In the Ben Zireg section, only the facies related to both the Lower and Upper Kellwasser events were identified.The temporal evolution of these different proxies allows in addition to propose a sea-level curve for the northern part of Gondwana. In the long term, the Frasnian is characterized by a transgressive trend interrupted by intermittent minor regressive trends. The end of the Frasnian is marked by a major regression during the Upper Kellwasser event, just before the Lower Famennian transgression.

The geographic location of the Sulu Sea in the far western equatorial Pacific results in the basin’s oceanographic sensitivity to: 1.) the East Asian Monsoon strength, 2.) the Kuroshio Current and open western Pacific conditions, 3.) Indonesian Strait geometry, 4.) past sea level, and 5.) the Indonesian Throughflow (ITF). Due to the sea’s unique bathymetry as a deep basin (~5,000 m maximum depth) surrounded by shallow sills with maximum depths of 440 m, Sulu Sea bottom water is relatively warm with minimum temperature of ~10°C, low dissolved oxygen, high carbonate concentrations, excellent CaCO3 preservation, and low bioturbation which combine to produce a remarkable sedimentological record. Sulu Sea sediments have previously been utilized to generate high-resolution paleoclimate records of past variability of surface ocean conditions using the planktonic foraminifera Globigerinoides ruber. However, past changes in the Sulu Sea subsurface and thermocline have been largely unexplored until now. Here I will show that reconstructing subsurface upper ocean conditions in the Sulu Sea reveals a rich archive of paleoclimatic information relating to past upper ocean dynamics. In this dissertation I seek to understand Indo-Pacific and global glacial-interglacial variability over the last four glacial cycles by generating foraminiferal δ18O, Mg/Ca-based temperature, and seawater δ18O (δ18Ow) records using the thermocline calcifying foraminifera Globorotalia tumida from high-resolution sediment core MD97-2141 from the Sulu Sea. Additionally, I extend existing G. ruber Mg/Ca-based temperature and δ18Ow paleoclimatic results to now span intervals of the last four glacial cycles. Sulu Sea thermocline reconstructions monitor regional paleoclimate on their own while also providing insight into surface variability when the surface and thermocline depth paleoclimatic records are compared.In Chapter 1 of this dissertation, I use Sulu Sea G. tumida reconstructions to investigate the North Equatorial Current (NEC) bifurcation latitude. After flowing east to west across the Equatorial Pacific, the NEC bifurcates into the northward flowing Kuroshio Current and the southward flowing Mindanao Current. The latitude of bifurcation migrates seasonally and interannually, controlling the partitioning of water between the two currents and the transfer of energy to the North Pacific. Using modern instrumental data, I show that by controlling the strength of the Kuroshio Current, the NEC bifurcation latitude also controls the leakage of relatively salty western Pacific water into the South China and Sulu Sea thermoclines, thus playing a major role in the salinity of the thermocline in both basins. I then use Sulu Sea thermocline δ18Ow generated using the foraminifera G. tumida from core MD97-2141 to show that the NEC bifurcation latitude was north during Heinrich Stadial I (17.5-15 ka), the Younger Dryas Chronozone (12.9-11.6 ka), and from ~9.5-8.5 ka and south during the Bølling-Allerød and early Holocene. Understanding the calcification depth of foraminifera is crucial for interpreting paleoclimate records. In Chapter 2 of this dissertation, I present δ18O records from six foraminiferal species and size fraction combinations from core MD97-2141 spanning ~12.75-10.75 ka. I calculate the δ18O difference between those records and previously published G. ruber data from the same core and use modern instrumental temperature and salinity data from the Sulu Sea to estimate calcification depths for each species and size fraction combination. I estimate that Sulu Sea G. tumida in the 400-600 μm size fraction calcify at a mean depth of 115m with the middle 95% of foraminifera geochemically analyzed yielding calcification depths between 99-131 m. G. tumida with no size constraint and in the >600 μm size fraction calcify at mean depths of 112 m and 107 m with the middle 95% of individual samples at 99-120 m and 88-117 m respectively. Globorotalia menardii was found to calcify at a mean depth of 106 m and the middle 95% of samples between 92-117 m. Neogloboquadrina dutertrei calcifies at a mean depth of 112 m (middle 95% between 102-120 m). Lastly, Pulleniatina obliquiloculata calcifies at a mean depth of 93 m (middle 95% between 68-108 m). Estimated calcification depth ranges for the all six species and size fraction combinations overlap. My results suggest that larger G. tumida calcify shallower in the Sulu Sea. I also show evidence that calcification depths in the Sulu Sea did not change for any of these species through time. Chapter 3 focuses on Marine Isotope Stage 3 (MIS3) (60-26 ka). I present results which demonstrate that the opening and closing of the ~36 m deep Karimata Strait at the southern terminus of the South China Sea with rising and falling sea level plays a substantial role in Sulu Sea surface salinity. I generated surface and thermocline δ18Ow records spanning ~125-20 ka in order to determine when the Karimata Strait was open and closed. I then use the depth history of the Karimata Strait to constrain maximum sea level during MIS 3 to -22±6 m relative to modern sea level and minimum possible sea level during MIS 5a and 5c (117-72 ka) to -12±7 m relative to modern. My record is the first to unequivocally demonstrate the Karimata Strait was subaerial during MIS 3 and suggests it could have facilitated the first human migration to the island of Borneo which occurred during that time. During the Younger Dryas paleoclimatic event (~12.9-11.6 ka), there was a return to near glacial conditions during the transition from the Last Glacial Maximum to the early Holocene (Termination I) (~18-11 ka). This was the most significant climate event during Termination I, but it is still unknown if it was a one-off event or if such millennial-scale events are intrinsic to glacial terminations. In Chapter 4 of this dissertation, I present Sulu Sea thermocline δ18O and Mg/Ca-based temperature records and a surface ocean Mg/Ca record to investigate millennial-scale events during Terminations II (~135-125 ka), III (~252-240 ka), and IV (~341-330 ka) in order to determine if the Termination II-IV events in the Sulu Sea demonstrate the same structure as the event during the Younger Dryas Chronozone. My results show that the millennial-scale event in the Sulu Sea thermocline during Termination III was most similar to the Younger Dryas Chronozone event, while the Termination II and IV events were largely similar to the Younger Dryas Chronozone with some differences. My reconstructions of these events are very consistent with the Termination III event in the Sulu Sea and somewhat consistent with the Termination II and IV events in the Sulu Sea being driven by the same mechanism as the Sulu Sea Younger Dryas Chronozone event. As a whole, my dissertation takes a unique approach to characterizing millennial-scale climatic events by combining surface and thermocline foraminiferal δ18O and Mg/Ca reconstructions and attributing mechanistic drivers to each. In doing so, I am able to draw the most possible information from a core. Such an approach that utilizes both the surface and the subsurface of the water column also allows interpretation of the differences between the surface and thermocline and these differences can improve our interpretations of previously existing surface records. Furthermore, my dissertation develops a new approach to constraining sea level using foraminiferal δ18O results by tying them to physical structures such as the Karimata Strait that have a direct relationship to sea level. The conclusions I reach in my dissertation shed light on North Equatorial Current bifurcation latitude variability since the Last Glacial Maximum, furthering our understanding of the controls of Indo-Pacific and western Pacific climate variability and the Indonesian Throughflow. They also improve our understanding of foraminiferal calcification depth in the Sulu Sea and through time, help constrain sea level during Marine Isotope Stages 3 and 5, and help develop our understating of millennial scale events during glacial terminations.

<p> Foraminiferal and thecamoebian biofacies were documented in the modem Korphos marsh located on the western coast of the Saronikos Gulf, Greece in order to define the general ecological features (such as salinity and proximity to marine influence) of the environments they occupied. These constraints were later used to identify fossil biofacies in subsurface marsh sediments at Korphos. </p> <p> Positive marine tendencies identified in fossil biofacies distributions were used for the first time to radiocarbon date relative changes in sea-level implied by a series of discrete, submerged tidal notches and beach rock adjacent to the marsh along the coast. Magnitude of subsidence events based on notch and beach rock data were measured to 2.9m, 0.5m, 1.3m, 0.39m, 0.47m, and 0.34m. The relatively unaltered v-shape of each notch profile suggested that sea-level rise was rapid and episodic. </p> <p> A comparison between the tidal notches and beach rock and an isostatically corrected model of sea-level for this area isolated the tectonic contribution to sea-level change and revealed that at least four of the six sea-level indicators plotted well-below predicted sea-level during subsidence. Therefore, the gradual sea-level rise of the late Holocene was interrupted by at least four sub-meter to meter-scale, step-wise increases in relative sea-level during coseismic subsidence of the Korphos marsh. The results of this study show how the combination of geomorphological and salt-marsh records have the potential to remove errors stemming from a lack of datable material for notches and autocompaction of marsh sediments when reconstructing local sea-level change. </p> / Thesis / Master of Science (MSc)

Coastal lakes, lagoons, and wetlands often provide excellent records of environmental change related to both marine and terrestrial processes. Although coastal paleoenvironments in the Caribbean have been a subject of increasing interest, long-term environmental reconstructions from lakes on the Atlantic side of the Caribbean islands are lacking. Laguna Limon is a freshwater lake in the El Seibo province of northeastern Dominican Republic. We collected a 315-cm sediment core from the center of the lake to examine lake evolution using loss-on-ignition and foraminiferal analysis. Loss-on-ignition results indicated the presence of a low-energy lagoon in the lake's present location between about 4700 and 1400 cal yr BP. During this period a foraminiferal assemblage dominated by the brackish-water Ammonia parkinsoniana but also containing relatively-abundant normal-marine salinity taxa (e.g., Quinqueloculina spp., Archaias angulatus, and Trochulina rosea) gradually was replaced by a low-diversity assemblage dominated by Ammonia tepida and Ammonia parkinsoniana, indicating a gradual decline in salinity due to the lagoon's growing isolation from the Atlantic Ocean. By 1400 cal. Yr. BP, the lake had become a shallow wetland, indicated by sediments with a high organic content. At 1200 cal. Yr. BP the lake flooded with freshwater, as it remains today. This study provides context for ongoing research into the environmental and human history of the Laguna Limon area. / Master of Science