Severe weather events that accompany climatic changes have been the main focus of many studies that want to highlight the large processes that surround us every day. These studies are based on years of data collection and other studies to help aid their pursuits. An area of major focus is identifying proxies and supplementary materials that help refine climate records of the geologic past. This study aims to identify reliable proxies for obtaining a record of severe weather events. The research consists of studying a coral species Pseudodiploria strigosa colonies with the goal to document, interpret, and describe the burial and re-exposure of massive coral colonies by severe storm or hurricane events, as recorded in coral growth patterns through density patterns and the analysis of CT-scanned coral specimens. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2019. / FAU Electronic Theses and Dissertations Collection

Archaeological investigations at Edwards Air Force Base (AFB) have been ongoing for more than 40 years. Yet the findings from the vast majority of those efforts are available only as grey literature that is known only to a relative few. The primary purpose of this thesis was to investigate a late Holocene decline in obsidian frequency reported by researchers working in the Bissell Basin and Rosamond Dry Lake region of Edwards AFB near the turn of the 21st century. A secondary purpose of this thesis was to shine a light on an area of the western Mojave Desert that is not widely known despite more than four decades of research. In order to explore the reported decline in obsidian frequency, I created an obsidian database using data gleaned from nearly 50 cultural resources management reports and supplemented those data with sourcing and hydration information for 39 additional obsidian artifacts. Those data were organized into tables, charts, and histograms to look for patterns that would support or refute the claim that obsidian use decreased significantly after the Gypsum time period (4000 to 1500 Before Present [B.P.]). Two patterns emerged from my analysis. The first was one where the overall abundance of obsidian at Edwards AFB did not decrease during the late Holocene, thus contradicting the conclusions made in the previous research. The second was one where the obsidian abundance shifted among the various regions of the installation. Yet these shifts are nowhere near as significant as the previously reported decline. Therefore, while the total amount of obsidian that entered the archaeological record at Edwards remained relatively stable from 1500 to 100 B.P., the amount of obsidian decreased in certain regions and increased in others. Although not within the scope of my original intent, my research also identified two areas for future research. The first involves an apparent pattern where the number of archaeological sites from which obsidian was recovered gradually decreases during the middle-Holocene even as the overall quantity of obsidian remains essentially unchanged. The second relates to the lack of a well-established hydration rate formula for obsidian recovered from archaeological sites on Edwards AFB. Ultimately, I concluded that the previous findings that obsidian declined during the late Holocene were affected by sampling bias and faulty data organization. Most archaeologists understand that poorly implemented sampling can lead to poorly derived findings and conclusions. What may not be as well understood is that a perfectly appropriate sample where the data are not organized well can also lead to flawed results and conclusions. It is hoped that this thesis will inform archaeologists not only about how the manner in which they organize their data can affect their interpretation of past human behavior, but also about additional research opportunities at Edwards AFB.

This thesis describes the results of a study of 33 tephra layers found within two peat sections near Anchor Point and Homer, Alaska, on the lower Kenai Peninsula. Numerous lower Cook Inlet volcanoes have been active through the Holocene. Tephra layers found at these two sites provide a partial record of their eruptive activity. The hazards that accompany this activity have increased as populations and commercial activities expand and air traffic over the region increases. The tephras analyzed for this study provide an initial geochemical database for the lower Cook Inlet volcanoes. The database is available in electronic format at the U.S. Geological Survey, Alaska Volcano Observatory. The Anchor Point and Homer sections contain tephras from Augustine, Iliamna, and possibly other volcanoes in the region. Anchor Point, the principal section for this study, yielded ten 14C ages ranging from 645 ± 85 cal yr BP at a depth of 14 cm to 8810 ± 205 cal yr BP at 270 cm. Seventeen tephra layers from Anchor Point and 16 from Homer were characterized by stratigraphic position, age, and grain-discrete major-element geochemical analysis by electron microprobe. Nine tephra layers are correlated by geochemical analysis between the Anchor Point and Homer sections. Several newly discovered tephra layers have been correlated with source volcanoes, three with Augustine and at least seven with Iliamna Volcano. The average recurrence interval of tephra fall events at Anchor Point is approximately 520 yrs.

Widespread Lake Bonneville sediments have been modified by river aggradation and degradation associated with Holocene fluctuations in the Great Salt Lake. Exposures of exceptionally abundant and well-preserved molluscan deposits in the Bear River Valley, Utah, allow detailed paleoenvironmental reconstruction of Holocene environments. The exposed basal unit consists of largely unfossiliferous deltaic silts and clays deposited during Lake Bonneville time ( roughly 11,000 - 13,000 yr B. P.). An unconformity representing at least 2000 yr separates the deltaic material from overlying highly fossiliferous stream sands. Eight species of molluscs, comprising a single community, occupied this low energy stream environment at 7690 ± 270 14C yr B. P. A second unconformity separates these sands from a dark brown silt unit deposited by a river-associated environment, most likely an over-bank marsh, at 2420 ± 135 14C yr B. P. Nine species of molluscs, comprising 3 communities, were present in this environment. Analysis of size-frequency distributions, percentage of pelecypod valves, preservation, and orientation of the shells that were present in each environment suggests that the 7690 ± 270 14c yr B. P. fossil assemblage has been only slightly altered by biostratinomic processes. The younger assemblage has also been altered, with the size-frequency curves of the smallest gastropods displaying normal distributions. Geomorphic and stratigraphic data from the Malad River show that water levels in the Great Salt Lake twice rose and fell significantly during the Holocene epoch. The oldest rise, to an altitude of at least 1288 m, occurred before 7690 ± 270 yr B. P., perhaps in response to a worldwide period of climatic cooling. This high-stand was followed by a fall of lake level roughly corresponding to the classic Hypsithermal Interval, about 7000 - 5000 yr B. P. A second rise occurred by 2420 ± 135 yr B. P., when the Great Salt Lake rose to approximately 1286 m. During this second rise, the Malad River overflowed its levees and later, as the Great Salt Lake receded for a second time, the river was captured by a headward-cutting tributary of the Bear River. The regional distribution of the fossiliferous deposits was controlled by the time at which capture occurred. Capture of the Malad channel by the Bear River occurred after the last fossiliferous sediments were deposited; thus no fossils are found downstream from the point of capture.

The aim of paleoenvironmental studies is to reconstruct characteristics of the past environment from fossil assemblages preserved in sedimentary strata. Thus, studies of modern surface assemblages, quantitatively correlated to the environmental parameters, are required before reliable interpretations can be made. For this dissertation, two different techniques were applied in two case studies: a reconstruction making use of a benthic foraminiferal transfer function from the intertidal marshes in the eastern Mississippi Sound, Alabama/Mississippi, and a qualitative reconstruction of ocean current activity on the Western Australian shelf. Modern salt-marsh foraminifera were collected from Grand Bay, Pascagoula, Fowl River, and Dauphin Island across several elevation transects and different salinity regimes. Cluster analysis yielded nine dead biofacies and five live assemblages from Open Estuarine to Upland Transition. Canonical correspondence analysis indicated a strong relationship between distributions of dead biofacies and elevation. Both dissolution of calcareous species in the organic marsh sediment and the long-term accumulative nature of the dead assemblage favored the use of non-estuarine dead assemblages. A Weighted Average-Partial Least Squared transfer function was applied to the surface data and yielded a Root Mean Squared Error of Prediction (RMSEP) of 0.14 m, which represents 33% Mean Range of Tide at Grand Bay and 39% at Dauphin Island. The transfer function was applied to two sedimentary cores from Grand Bay and two from Dauphin Island, which revealed disparate developments between the regions during the last 1,900 years. While both Dauphin Island cores indicated relative sea-level trends aligned with other Gulf of Mexico studies, Grand Bay was likely impacted by a river avulsion event disconnecting Grand Bay from fluvial sediment influx, and by the erosion of a protective headland, Grand Batture Island. Sediments spanning the last ~100 years contained increased abundances of low marsh foraminifera likely associated with coastline erosion, which was most prominently displayed by a lithology shift towards grey silt in the Dauphin Island cores. Surface carbonate sediments from Western Australia’s Northwestern Shelf and Carnarvon Ramp were collected from 127–264 m water depth. Foraminiferal assemblages changed between 127 m and 145–264 m due to rapidly decreasing water temperature in the thermocline, and loss of sufficient light for support of “larger” benthic foraminifera. Latitudinal differences were likely caused by three factors: (1) limited influence of the warm Leeuwin Current to support tropical taxa at the sampled depths, (2) reduced habitat diversity on the narrow Carnarvon Ramp compared to surrounding shelves, and (3) differing water-mass characteristics. The gathered information was used to interpret the assemblages from a Carnarvon Ramp core (total depth 300 m), providing insight into the activity of the warm, surficial Leeuwin Current for the last 3.54 My (Pliocene). Abundant infaunal taxa were inferred to indicate low oxygenation, increased supply of organic matter, and high sea-surface productivity during the absence of the Leeuwin Current above the coring site. Dominance of epifaunal species signified higher oxygenation at the sediment-water interface when upwelling of nutrient-rich waters was effectively suppressed by the Leeuwin Current. Around 1.14 Ma, waning of hypoxic conditions was initiated until a more substantial change was marked at 0.91 Ma. Suspension-feeding sponges became common sediment constituents during a Leeuwin Current flow optimum at ~0.6 Ma. The epifaunal taxa dominance persisted on the modern shelf, yet short episodes of infaunal peaks were likely caused by lateral shifts and fluctuating influence of the Leeuwin Current during more intense glacial cycles.

[Truncated abstract] Environmental changes have had major impacts on past human societies across the globe, and a better understanding of this human-environment interaction is necessary for building societies with resilience towards future environmental change, and to effectively conserve areas of natural environments into the future. Regions such as the Yangtze delta, that have a long history of rice cultivation (dating to at least ca. 7000 BP) and a high density of prehistoric sites, provide an ideal backdrop to study both long-term human-environment interactions, and the environmental impacts of agricultural societies. This study aims to provide Holocene palaeoenvironmental reconstructions for three study sites in the Yangtze delta region, with the principle objectives of detecting human activity – particularly that associated with the development of rice agriculture – and identifying environmental changes within the palaeoenvironmental records. A parallel aim is to develop the use of quantitative biomarker and compound specific isotope analyses in Holocene palaeoenvironmental investigations, including in the detection of early agricultural environments, through analysis of sedimentary deposits. Palaeoenvironmental records for the three study sites, Qingpu, Guangfulin and Liangzhu, cover the time period from ca. 12,000 to ca. 400 BP. '...' Greater proportions of coniferous and deciduous taxa early in the records (prior to ca. 7000 BP) indicate comparatively cooler conditions, while the increased abundance of Chenopodiaceae during that time suggests both cooler conditions and a greater marine influence in the region. Palaeoenvironmental data obtained during this study suggest agriculture in the delta region to have gradually increased in importance from ca. 7000 – 2400 BP. The Guangfulin study site yielded the earliest evidence of agricultural activity, dating to ca. 7000 BP, principally in the form of a corresponding increase in Poaceae (Oryza comp.) abundance and decline of arboreal forest taxa. Subsequent periods of agricultural intensification are noted at ca. 5360 BP at Liangzhu and ca. 4700 BP at Guangfulin. Following the final period of intensification at Qingpu and Guangfulin (ca. 2400 BP), the extent of cultivated land in the delta region may have been comparable to modern times. Technological development during the early dynasties, particularly the greater availability of iron tools, is likely to have been a major factor driving the agricultural intensification detected ca. 2400 BP. The large tracts of natural vegetation detected by this research prior to ca. 2400 BP, would have afforded a degree of resilience to the human inhabitants of the delta region. Following the contraction of natural vegetation in the delta region, societies would have gained some resilience through access to the extensive trade network of the Chinese state. Resilience acquired through these means may, in part, account for the longevity of agricultural societies in the Yangtze delta region of China.

Abstract not available

This dissertation presents results from three studies that address major scientific questions in glacial geology and paleoclimatology for the late Pleistocene and Holocene using relatively new geochemical and statistical techniques. Each of the studies attempts to answer a longstanding question in the respective field using geochemical or statistical methods that have not been applied to the problem thus far. A longstanding question in glaciology is the nature and mechanism of the so- called "Heinrich events" of the last ~60 ka. These massive iceberg discharge events into the North Atlantic from the partial breakup of the Laurentide Ice Sheet are identified from distinct ice rafted debris and detrital carbonate layers in marine sediment cores. The mechanism associated with the initiation of these events is commonly thought to be related to internal ice sheet instabilities. However, Heinrich events consistently occur following a long cooling trend that culminates in an extreme cold event, thus suggesting a possible triggering mechanism by climate. Recent modeling work has proposed an oceanic mechanism associated with ocean warming, but no physical evidence has been made available to date. To test this ocean-warming hypothesis, we measured temperature sensitive trace metals and stable isotopes in benthic foraminifera from a sediment core collected in the western North Atlantic that spans the last six Heinrich events and compared our results to climate model simulations using CCSM3. Our results show subsurface warming occurred prior to or coeval with nearly all of the Heinrich events of the last ~60 ka, thus implicating subsurface ocean warming as the main trigger of these rapid breakups of the Laurentide Ice Sheet. In the field of glacial geology a longstanding question has been the timing of alpine glacial advances during the Holocene. A number of studies have interpreted several Holocene glacial advances in western North America, but age control is based largely on relative dating techniques, which have been shown to be in error by up to 10,000 yrs in some cases. Based on 124 ¹⁰Be surface exposure ages from twenty cirque moraines in ten mountain ranges across western North America, glacier were retreating from moraine positions during the latest Pleistocene or earliest Holocene and not throughout the Holocene epoch as previously assumed, thus requiring a refined interpretation of Holocene glacial activity in western North America and the associated climate forcing. In the field of paleoclimatology a question regarding how global temperature varied over the entirety of the Holocene epoch has remained to be answered for some time. While many temperature reconstructions exist for the last 2000 years, a full Holocene temperature stack does not exist, despite its potential utility of putting modern climate change into a full interglacial perspective. Based on a global composite of 73 proxy based temperature record, a Holocene temperature stack was constructed and used to demonstrate that a general cooling of ~1°C has occurred from the early to mid Holocene and that centennial and millennial scale variability is modest. We account for both temperature calibration and chronologic uncertainties using a Monte Carlo based approach. Our results are consistent with prior reconstructions of the last 2000 years and now allow for a full Holocene temperature perspective for evaluation with present and future climate change. / Graduation date: 2011 / Access restricted to the OSU Community, at author's request, from May 5, 2011 - May 5, 2012

Two deeply buried, well-stratified, and well-dated components dating to the Early Holocene period were excavated at the Richard Beene site (41BX831) in Bexar County, Texas. This thesis utilizes both qualitative (interpretation of maps) and quantitative (unconstrained clustering) spatial analysis techniques to identify site structure and assess post-depositional disturbance by analyzing patterns among artifact categories, selected artifacts, and features from these components. Results of spatial analysis are compared to expectations of the archaeological record based on previous research. Each component revealed a distinct pattern. The Lower Medina component (ca. 6900 B.P.) is well preserved and spatial analysis showed clear distinctions between domestic and peripheral zones. The Upper Perez component (8800 B.P.) is a fluvial lag deposit of displaced artifacts and fire-cracked rock features. Results of spatial analysis confirmed that most, if not all, of this component is disturbed, revealing no site structure.

Pollen profiles from two lakes, Tawny Pond (44°48’59”N, 77°10’54”W, 276m) and Stoll Lake (44°58’16”N, 77°17’22”W,303m) in Addington Highlands, eastern Ontario, Canada were analyzed to understand the effects of late-Holocene climate change and European settlement on eastern Ontario’s forests. Both lakes were analyzed at high temporal resolution and record vegetation dynamics over the last 1000 years. Throughout the past 1000 years, Pinus, Tsuga, Betula, Quercus, Acer and Fagus were the dominant taxa in the pollen record. The pollen records show vegetation response in relation to the Medieval Warm Period and the Little Ice Age. From 970-1200 AD the forest was dominated by hemlock, beech and maple trees. From 1200-1870 AD the forest composition changed as pine and boreal trees became more abundant and/or had increased relative pollen production. Most recently, since 1870 AD, herbaceous plants (weeds) increased, whereas softwoods decreased and hardwoods increased, due to landscape changes associated with European settlement. These results show that high resolution studies of unvarved lakes, with an appropriate chronology, can detect multi-decadal climate variability. This thesis was also concerned with making management suggestions to the forestry community. Future climate change will likely create a forest composition more similar to that of the Medieval Warm Period than the time of European colonization, and thus should be the basis for forest planning.