GEOMORPHIC CONSTRAINTS USING FLANK MARGIN CAVES AND REMNANT VOIDS FROM THE CARIBBEAN

Caves exposed in the limestone terraces and cliffs of Aruba, Bonaire, and Curacao display several mechanisms of formation. There are three dominate mechanisms that lead to the development of these voids: flank margin dissolution, littoral processes, and differential erosion. In addition, several other mechanisms produce voids at less frequent occurrences, which include: talus slopes, constructional caves via tufa growth, and fracture caves. Comparing the morphology and distribution of these caves and voids to their location above sea level in uplifted cliffs provides a measure of cliff retreat rates, uplift rates, and denudation rates. Unfortunately, because many of these remnant voids and caves are severely degraded (<50% their original size), cliff retreat rates can only be estimated as an extreme minimum. These minimum cliff retreat rates vary between ~5mm/1000 yrs to ~50mm/100 yrs. Uplift rates are conservative estimates, and vary due to uncertainty in cave development timing; however, they tend to match other proxies such as coral terraces well. Denudation rates are poorly characterized by field observations on these islands, but estimates based on laboratory dissolution experiments are currently being measured. Overall, these caves and notches provide a detailed geomorphic history that has been mostly overlooked as insignificant erosional features.