Pore Space in Carbonate Tidalites: Paleoclimatic Aspect

Resumo

Carbonate sediments in tidal zones are characterized by microgranular textures, insignificant content of the clayey material, and abundance of the cyanobacterial formations. The arid climate fosters the formation of dolomitic tidalites in association with evaporites containing numerous stromatolite interlayers. Dolomitic tidalites make up the lower and upper elements of the three-member transgressive–regressive cyclites, whereas tidalites deposited in a humid climate are confined to the base of two-member limestone cyclites. In both cases, the pore space is created by the abundance of bacterial formations, a very specific feature responsible for the sharp anisotropy of permeability.