Calcium and clumped isotopes are affected by carbonate recrystallization in fundamentally different ways, and are affected by different factors. Here, they are used to study an evolving carbonate margin (Present day western Bahamian slope), in order to quantify the rate of recrystallization and the degree of fluid flow into the margin. Results show that, with the onset of drift deposits in the Straits of Florida, fluid flow into the margin increased a great deal, demonstrating the importance of larger platform structure in governing the nature of diagenetic reactions.