2015 GSA Annual Meeting in Baltimore, Maryland, USA (1-4 November 2015)

Paper No. 217-10
Presentation Time: 9:00 AM-6:30 PM


SUMRALL, Jonathan B., Geography and Geology, Sam Houston State University, PO Box 2148, Huntsville, TX 77341 and LARSON, Erik B., Natural Sciences, Shawnee State University, 940 Second St, Portsmouth, OH 45662, karst@shsu.edu

A growing body of research has documented island karst features on the dolostones on several Caribbean and Atlantic islands. Dolostones, ranging from Eocene to Pliocene in age, have been examined for karst features on Isla de Mona, Puerto Rico; Aruba; Bonaire; Curacao; Barbados; and Cayman Brac. Karst features on these islands range from small pits to large flank margin caves; one of the more intriguing relationships between karst and dolostone occurs on Isla de Mona, Puerto Rico where microbial processes have been hypothesized to couple flank margin cave development and dolomititzation.

The most common featureson these islands are remnant voids that appear as discrete notches in cliffs and slopes of these island dolostones. Most previous work on these carbonates dismisses the remnant voids as sea notches; however, detailed examination of these voids, including morphology, speleothem content, and stratigraphic position, suggests that many of these features are actually remnant flank margin caves. Both sea notches and flank margin caves are tied to the position of sea level, so they both provide similar controls on the position of sea level. However, flank margin caves provide additional diagenetic and geomorphic information, especially involving cliff retreat and uplift rates. If these remnant voids were originally sea notches, cliff retreat would have removed the features from these cliffs. It would take more time for cliff retreat to remove flank margin caves due to their larger footprint(possible) and lateral position relative to the coast that they formed (likely). Minimum cliff retreat rates are determined using morphology of remnant voids, elevation above modern sea level, and paleo sea level curves. However, more documentation and work is needed to produce a thorough database of island karst features on and in island dolostones.