Authors: Chelsea Randall, University of West Florida, Johan Liebens*, University of West Florida
Topics: Soils, Coastal and Marine, Geographic Information Science and Systems
Keywords: soils, marine terraces, GIS
Session Type: Poster
Presentation File: No File Uploaded
Previous work to define marine terraces along the coast of the northern Gulf of Mexico primarily relied on unsystematic topographic studies and showed little consensus on the number and spatial extent of terraces. Research investigating soil development in the region is also limited. The objective of this study was to consistently and semi-automatically identify marine terraces in Northwest Florida and to determine changes in soil development with terrace elevation, and thus with age. The study utilized GIS and a LiDAR-derived DEM to apply a Surface Classification Model (SCM) for selection of areas with low slope and low surface roughness. Hypsographic analyses of the SCM output identified potential terrace surfaces but visual interpretation along transects across the surfaces was necessary to refine the bounding terrace elevations. Five terrace levels were ultimately identified. gSSURGO soil data showed that solum thickness generally increased with increasing terrace elevation but the lowest terrace had the greatest solum thickness due to the presence of thick Histic epipedons and thick Spodic horizons. Organic matter content in the A horizon was highest in the two lowest terraces, probably due to shallow groundwater tables that inhibit decomposition. Bt horizons exhibited a thickening and increase in clay content with increasing terrace elevation. Bt horizon depth also generally increased with elevation but decreased on the highest terrace likely due to erosion associated with the advanced age of the surface. This study demonstrates that GIS and LiDAR-derived DEMs are valuable tools to systematically and semi-automatically map marine terraces on a regional scale.
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