6 - Morphology of Carbonate Escarpments as an Indicator of Erosional Processes

Summary

Abstract

Large sections of the Blake, Florida, and Campeche Escarpments have been imaged by GLORIA, and this common data type allows a comparison of the morphology of these escarpments and inferences about the erosional processes that have shaped them. Four morphologic provinces have been identified as follows: (1) shallow valleys with tributary gullies, which coincide with areas of minimal erosion of the platform edge; (2) box canyons, which overlie areas of differential basement subsidence and fractured carbonate rocks; (3) straight terraced sections coinciding with areas of more uniform basement subsidence, but where varying lithologies exposed at the platform edge are being differentially eroded; and (4) straight unterraced sections where the lithologies of the carbonate rocks appear to be uniform. These different provinces are interpreted to be surficial expressions of processes that have shaped these escarpments through their histories.

Introduction

The escarpments at the edges of the Blake-Bahama, Florida, and Yucatan carbonate platforms are some of the largest cliffs on the surface of the earth. The Blake Escarpment extends along the eastern side of Florida and the northern Bahamas for about 450 km and has as much as 4,000 m relief. The Florida Escarpment extends along the western side of Florida for about 650 km and has about 2,000 m relief. The Campeche Escarpment rings the eastern and northern margins of the Yucatan Peninsula and has about 2,000 m relief (Figure 6–1).