Karst terrains are landscapes sculpted and formed through the dissolution of rock through chemical action of lightly acidic waters from rainfall, coastal mixing, and in some rare cases upwelling of hot, acidic waters from deep in the earths crust. All of the Cayman Islands are carbonate platforms composed of ancient coral and reef related limestones and dolostones. These rocks were formed by the direct actions of calcareous reef building organisms directly (such as coral and coralline algae), and by the accumulation and deposition of sand or clasts of weathered reef materials, ooids, and other marine organisms hard shells (e.g. Forams, and Strombus shells, etc). On Little Cayman Island, reef building, along with reef exposure due to tectonic uplift as well as sea level fluctuations during the Quaternary glacial cycles has resulted in a unique karst landscape that has been shaped by duelling action of exposed limestone being karstified by acidic rainwater, submerged limestones from the Miocene being chemically changed and “dolomitized” after re-submersion in the ocean after karst had begun forming, and continual fluctuations between those states for fringing and ledge wall reef structures around the island.
The results, are striking collapsed cave and sinkhole features, jagged pinnacle and pock features, fluted rillenkarren, and unique void fill minerals, such as the popular “Caymanite”. While several notable geologists have visited the island and done (in at least one case substantial) some work in characterising the geology of Little Cayman Island, few have looked hard at the development, extent, and nature of Little Cayman karst… Which means I’ve got plenty to keep me busy over the next two months!
The Ocean Evolution Institute 