Why do calcium carbonate sediments form in shallow gulfs in dry climates?

In shallow gulfs located in arid climates, the formation of calcium carbonate sediments is primarily driven by the specific environmental conditions of these regions, where there is minimal influx from perennial streams.1

In these arid zones, high rates of evaporation significantly influence the water's chemistry. Because these gulfs are often semi-restricted from the open ocean, the limited water exchange and lack of river runoff lead to increased salinity and altered chemical conditions. The precipitation of calcium carbonate in these settings is a form of chemical sedimentation, which geologists analyze by considering factors such as the water's pH and redox potential.123

Furthermore, the formation of carbonate sediments is generally favored in warm, shallow marine environments. While these gulfs may also be sites for evaporite deposition—where minerals like gypsum and halite form as water volume is reduced—the accumulation of calcium carbonate remains a distinct and common feature of these protected, shallow-water coastal settings.4512