Trend and Phasing of Carbonate Accumulation in the History of the Earth

Abstract

In the geological history of the Earth, there has been a significant change in the composition and areas of carbonate accumulation, which reflects the general evolution of the formation of carbonate deposits, paleogeographic and geochemical settings, and different stages of this evolution. At the Archean–Proterozoic boundary, acidic conditions in water reservoirs changed to moderately acidic, which resulted in the appearance of iron carbonates. The second milestone is the Siderian–Rhyacian boundary, when intensive assimilation of CO2 led to the development of alkaline conditions in water reservoirs and the accumulation of Mg carbonates. Carbonate accumulation itself occurred in the inland water reservoirs. The third milestone is the Vendian–Cambrian boundary, when skeletal fauna appeared, and carbonate accumulation became largely biogenic. Along with the basins of the continental block, there appeared new oceanic areas of carbonate accumulation, where the skeletons of nekton organisms became a significant supplier of material. The fourth milestone—the Paleozoic–Mesozoic—was the beginning of the accumulation of the proper oceanic deep-water carbonate sediments. The fifth milestone is associated with the Cretaceous period, when oceanic carbonate accumulation sharply increased due to accumulation of planktonic organisms.