Lanterna Rally

Author: Bo Li

Publisher: ProQuest

Published: 2006

Total Pages:

ISBN-13: 9780542811951

It has been long debated whether or not tidal channels meander through space and time. If so, at what magnitude did they meander; and how did their changes in space and time relate to the morphodynamics of salt marsh development and facies configuration of transgressive valleys? Many have argued that the laws that govern the fluvial streams are equally valid for tidal channels and tidal channel networks. However, there is a lack of field measurements to support the aforementioned statements. Further, the dynamic relationship between tidal channel network development and salt marsh evolution was poorly understood in terms of erosion vs. accretion in response to sea-level changes. Also, models of salt marsh initiation and tidal channel development within transgressive valleys in the US Atlantic coastal plains are not well studied as compared with those of the North Sea in Europe. In an attempt to systematically study the dynamic relationships between the salt marshes and tidal channel networks of transgressive valleys and other system forcings (such as sediment supply, sea-level changes, topographic control, and halophyte production), I chose the Great Marsh area at Lewes, Delaware. To better address these issues, other estuarine tidal basins and incised valleys along the Delaware Bay and Atlantic coasts were studied to serve as modern analogs for the support of my findings in the Great Marsh area. The following major topics/themes are covered and explored in this research study: geologic framework of the study area, modern-ancient analogs, sources of sediment supply, morphometric properties of tidal meander planforms, construction of the paleotopography, hypsometric and volumetric analyses of the incised valley fill, Holocene evolution of the Great Marsh, modern analogs of marsh initiation and tidal meandering development, and discussions of various topics such as tidal channel network initiation and development, incised valley system's self-adjustment in response to changes in sea-level and sediment supply, and facies models as applicable to the transgressive incised valley fills. (Abstract shortened by UMI.).