The aim of the research was to provide new sea-level index points,with the intention of identifying any cross-channel similarities and comparing the results to geophysical models of relative sea-level change. The research successfully provided new sea-level index points from the Pevensey levels, East Sussex; the Canche Estuary, Pas de Calais and the Somme Estuary, Picardie, which were validated using stratigraphic pollen,diatom,foraminiferal snd AMS radiocarbon dating analysis. The results pointed to the presence of a coastal barrier thoughout the mid-Holocene at Pevensey and the Somme which complicated the pattern of coastal sedimentation observed at these sites. A clear pattern of barrier de-stabilisation can be seen to take place either side of the Channel c.3000 years cal BP. A cross-channel comparison identified three similar transgressive events either side of the English Channel, c. 5500, 3000 and 2200 cal years BP. The observed results from each site were then compared to the predicted data( Lambeck pers.comm) .in order to determine whether the observational data could be used to validate the modelled data. The comparisons showed that for the sites in south east England the modelled data tended to over-predict sea-level rise for the mid-t o late- Holocene whereas the model tended to under-predict sea-level rise for the sites in northern France. The new observational data which the research provided could be used to further validate Lambeck's (1990,1997) geophysical model. The effects of local coastal processes, such as tidal range, crustal subsidence and barrier-dynamics were used to aid the comparisons between the pattern of sediment deposition and thus the sea-level signals. These findings suggested that reconstructions should be restricted to sites at an estuary-sized scale.

Thesis (M.S.)--Naval Postgraduate School, 1980. / Includes bibliographical references (leaves 90-91).

Sea-level fingerprints, the spatial patterns of sea level change resulting from rapid melting of glaciers and ice sheets, play an important role in understanding past and projecting future changes in relative sea level (RSL). Over century timescales, the viscous flow of Earth’s interior is a small component of the total deformation due to ice loading in most regions, so fingerprints computed using elastic Earth models are accurate. However, in regions where the viscosity is orders of magnitude lower than the global average, the viscous component of deformation can be significant, in which case it is important to consider models of viscoelastic deformation. There is evidence that the glaciated regions of Alaska, Western Canada and USA, and the Southern Andes are situated on top of mantle regions in which the local viscosity is several orders of magnitude lower than typical global mean values. The goal of this work is to determine the importance of viscous flow in computing RSL fingerprints associated with future ice mass loss from these regions. Version 5.0 of the Randolph Glacier Inventory is used to estimate the ice load distribution required for calculating sea-level fingerprints. For the glaciated regions that have lower than average viscosity, fingerprints were calculated using an elastic Earth model and a 3D viscoelastic model to quantify the influence of viscous flow on the predicted sea level changes. Using glacier mass loss values for the intermediate future climate scenario Representative Concentration Pathway (RCP) 4.5, the global sea level response was computed at 2100 CE relative to 2010 CE due to melting from all glacier regions. On comparing the results of the two models it was found that ice-load-induced viscous flow contributes significantly (more than a few cm) to the RSL fingerprints only in near-field regions. However, in these regions, the non-elastic contribution can be 10s of cm. For example, at Juneau, USA the elastic calculation gave relative sea level changes of ∼ −45 cm, compared to ∼ −120 cm based on the viscoelastic calculation.

No description available.

Globally, sea levels have risen in the last century, and various projections suggest substantial increases in sea level due to climate change in this century. In Nigeria, there are no up-to-date sea level rise (SLR) assessments for the coast. Much of the Nigerian coast is low lying with the consequence that a 1 to 3 metres rise in sea level, which may result from eustatic or climate change, will have a catastrophic effect on the human activities in these regions. This study examines the consequences of continued sea level rise with a focus on erosion and inundation for the Nigerian coast and considers the coastal management practices of coastal partnerships (CPs). The Nigerian coast has been delineated according to distinct geomorphological units, which include the Barrier, Mud, Delta and Strand coasts. The Bruun model has been used to compute shoreline recession along the Nigerian coast with the exception of the Mud coast. A Geographic Information System (GIS) was used to develop inundation models and examine the impact scenarios that SLR will have on critical elements, which include land, population, economic activity (Gross Domestic Product), urban extent, agriculture and wetlands with the aid of high quality spatially disaggregated global data. A case study approach was used to assess the management practices of Pro-Natural International Nigeria; Niger Delta Wetland Centre, Niger Delta Development Commission; and Flood Erosion and Coastal Zone Management, Rivers State with the aid of a suite of systemic sustainability appraisal indices. Results indicate that shoreline recession will be mild along the coast while substantial loss due to inundation of the critical elements is expected for all the scenarios considered. The sustainability assessment indicates that the CPs did not meet the required standard for sustainability, however there was evidence of constructive management in some of them. This study has been able to provide up-to-date baseline data concerning the vulnerability of the coast to SLR for the four coastal systems in Nigeria. The coastal sustainability assessment, which is the first ever in Nigeria, reflects the need for corrective measures in the management practices of the CPs to achieve a sustainable coast in the light of coastal hazards.

No description available.

Thesis (Ph.D.)--Boston University / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / This study employs a suite of geophysical, sedimentological, and chronostratigraphic tools to investigate the complex interactions among changes in sea level, climate, and sedimentation processes that have driven Holocene coastal evolution. These interrelationships were explored in investigations of three coastal sites with diverse sea-level and sedimentation histories: the Egyptian Red Sea (Wadi Gawasis), southern Brazil (Pinheira) and the Western Gulf of Maine (Plum Island). This study demonstrates the need to quantify the integrated impacts of spatially-diverse changes in global (sea level), regional (climate, sea level), and local (sedimentation) factors if we are to predict large-scale coastal evolution in response to the ongoing acceleration in sea-level rise. The mid-Holocene in both the Red Sea and southern Brazil was characterized by higher-than-present stands of sea level. Sedimentological, malachological, foraminiferal, and rheological studies at Wadi Gawasis reveal that this resulted in the formation of a shallow bay that reached its maximum extent prior to a 1.5-m highstand at 5 ka, demonstrating a dominance of sedimentation processes despite contrary sea-level change. Early bay closure was driven by sediment inputs enhanced by a wetter climate. Slowly falling sea level and coincidental climatic aridization allowed for the establishment of an Egyptian harbor 4 ka, followed by late-stage progradation dominated by sea-level fall. In southern Brazil, an abundant sediment supply and sea-level fall following the mid-Holocene highstand were responsible for the development of the 5-km wide Pinheira strandplain, composed of regular beach and dune ridges. Identification of anomalous barrier, lagoonal, and tidal fill deposits within this plain demonstrates the complex nature of the sedimentological response to a small-scale change in the rate of sea-level fall. By contrast, Plum Island formed in a regime of rapid sea-level rise that reworked shallow shelf and fluvial deposits. Geophysical and sedimentological studies reveal a complex barrier formation (aggradation, spit accretion and progradation), including evidence for inlet migration and closure. Time-transgressive backstripping of backbarrier facies shows that bay sedimentation in a regime of slowly rising sea level reduced tidal-prism and produced inlet closure. This is first study to demonstrate that the direct impact of backbarrier processes influencing barrier island development. / 2031-01-02

The MacKenzie Basin, located in the District of MacKenzie in the southern part of the Northwest Territories, Canada, includes a thick succession of Middle Devonian strata. This basin, bordered to the east by the Canadian Shield and to the south by the Tathlina Uplift, was directly connected to the open ocean that lay to the northwest. Comprehensive facies analyses of the Chinchaga Formation, Lonely Bay Formation, Horn Plateau Formation, and Horn River Formation, which formed in this basin during the Early and Middle Devonian, shows that sedimentation was largely controlled by eustatic sea level changes. Accordingly, these strata reflect a long period of sea level rise during which shallow water evaporite deposition in the Eifelian was followed by open marine conditions that led to reef growth in the Givetian, and ultimately pelagic shale deposition in the Frasnian. The Horn Plateau Formation is comprised of numerous isolated reefs that are located along northeast-southwest direction over a distance of 350 km along the MacKenzie Basin ramp. Reefs in the southwest are dominated by stromatoporoids whereas those in the northeast are dominated by corals. Although difficult to prove, it appears that the distribution of the stromatoporoids and corals may have been controlled by nutrients coming from coastal upwelling or runoff from the exposed Canadian Shield. Effects of early diagenetic processes were evident on the MacKenzie Basin ramp in an intensely bioturbated facies in the Lonely Bay Formation. Burrows from this facies are dolomite-filled further down the ramp and calcite-filled proximal to the Canadian Shield in the east. Anoxic conditions and the presence of sulphate reducing bacteria may have promoted early dolomite formation in the burrows located in deeper water. Burrows further up the ramp were oxygenated and show evidence of input from the exposed Canadian Shield, both of which may have inhibited low-temperature dolomite formation.

published_or_final_version / Applied Geosciences / Master / Master of Science

The aim of this project is to study the impact of future sea level rise on coastal development in Hong Kong and to review current marine design work standard of Port Work Design Manual. Projection of sea level rise to 2060 and 2099 from past tide gauge records has been carried out in this study. The recent redevelopment area, Kai Tak (Old airport), is chosen as study area. Data has been obtained from Hong Kong Observatory, IPCC Fourth Assessment Report (2007), Lands Department and Civil Engineering and Development Department to reconstruct and project the past and future sea level change in Hong Kong respectively. Global and local sea level are expected to rise in the 20th century from past studies. The increasing acceleration of sea level rise in my projection has an significant implication to Kai Tak area that existing formation level of reclaimed land and current marine design work standard for redevelopment may not be adequate to resist coastal flooding and inundation associated with sea level change in the near future. By 2099, Kai Tak area may be flooded in extreme cases, which is an issue that upgrading existing marine structure and reviewing current marine design standard needs immediate attention. / published_or_final_version / Applied Geosciences / Master / Master of Science