FRACTAL ANALYSIS OF MAINE'S FORMERLY GLACIATED SHORELINE TESTS ESTABLISHED COASTAL CLASSIFICATION SCHEME

Although fractal techniques have been used to characterize the complexity of different coastlines, relatively little work has been done to associate the resulting D values with geological and geomorphological processes. Differentially eroded bedrock outcrop patterns strongly shape Maine's shoreline. The trend of the bedrock determines the relative exposure of glacial deposits to prevailing waves, and the erosion of the glacial deposits. Researchers have divided the Maine coast into four distinct compartments based on the resulting shoreline. Average fractal dimensions (D) are calculated for Maine's four coastal compartments using a GIS approach and digitized U.S. Geological Survey 7.5-minute series topographic quadrangle maps. The D values indicate relatively little complexity for the southwest coastal compartment (avg. D = 1.11), higher complexity for the south-central compartment (avg. D = 1.35), and intermediate complexity for the north-central compartment (avg. D = 1.23). Our analysis suggests that the northeastern compartment should be further divided into two subcompartments (Cobscook Bay and non-Cobscook Bay), which have average D values of 1.37 and 1.18 respectively. Subdivision of the northeast coastal compartment is also supported by the geologic makeup of the region. Statistical tests show that all of the geologically different coastal compartments can be discriminated in terms of D at the 95% confidence level, whereas the geologically similar compartments (south-central compartment and Cobscook Bay subcompartment) cannot be statistically distinguished.