LAKE FORMATION ON CARBONATE PLATFORMS---A PROCESS DRIVEN MODEL

Based on their physical and chemical characteristics, lakes in the Bahamas can be placed into two general categories—constructional and destructional lakes. Constructional lakes are formed by aggradation and isolation and occur in response to sea level fluctuations, while destructional lakes occur as dissolution and collapse features in immature eogenetic limestones and occur at all times. We developed a qualitative and quantitative lake formation model for the Bahamas and other carbonate platforms that relate climate-driven processes to the development of the different styles of lakes. Constructional lakes are divided into highstand and pre-highstand features and destruction lakes include blue holes and karsted depressions. These qualitative categories were tested using quantitative data and analyzed using a non-metric multidimensional scaling model (NMDS) for the following variables—surface area, depth (max), pH, average alkalinity, average salinity, total dissolved solids, dissolved oxygen (bottom), Ca²⁺, Mg²⁺, Na⁺, K⁺, Fe^2-, Cl^-, and SO₄^2-. In each case, the quantitative model confirmed the categories from the qualitative model.

The value of this lake model is three-fold. First, it provides a way to classify and categorize lakes on carbonate platforms that is correlated with formational processes. Second, the model provides a qualitative and quantitative way to describe lakes and their attributes that corroborate with one another. Third, the model can be used as a predictive tool for understanding faunal distributions, the effect of sea level on island geomorphology, and potential linkages with productivity and petroleum formation.