Coastal cave development in Puerto Rico

The goal of this study was to provide a comprehensive and updated inventory of the coastal caves of Puerto Rico in an effort to contribute to a better understanding of cave development in this island setting. A total of 63 coastal caves were surveyed and analyzed using detailed cartography, morphometric analysis, resource inventory, and photo documentation. Located along the northern, western, and southern coastlines of Puerto Rico, many of these features, because of their small size and relative obscurity, had not been thoroughly studied in the course of previous fieldwork. Prominent sea cave (littoral) development was noted in all coastal areas, but previously undocumented examples of flank margin speleogenesis were also identified within the Quaternary eolianite and adjacent limestone exposures along the northern coast. Morphometric analysis of all the completed cave maps revealed that the 10 flank margin caves could be graphically distinguished from the 53 sea caves by comparison of cave perimeter to total cave area. Furthermore, morphometric comparison of multiple spatial parameters was sufficient to differentiate intact from denuded flank margin caves as well as identify segments within some flank margin caves that had been modified by littoral breach and/or cliff retreat. This study revealed a surprising variety and abundance of cave resources along these dynamic and complex Atlantic and Caribbean shorelines, utilizing a methodology capable of differentiating between flank margin and littoral cave development that can be further used to determine the speleogenic origins of coastline cave resources in other carbonate island settings.