Stratigraphic position and distribution of different types of bryozoan-algal limestones in Miocene of Northern Caucasus
Bryozoan-algal limestones known in the Miocene sediments of the North Caucasus and stratigraphically confined to the lower Chokrakian, lower-middle Sarmatian and lower Meotian. Within the North Caucasus (the central part of the Eastern Paratethys) they are distributed mainly in the West Caucasus, Central Caucasus, and Eastern Caucasus. Bryozoan-algal limestones traced as biohermal bodies and lenticular layers. The thickness of layers from the first cantimeters to 50 m and a length from a few meters to hundreds of meters. In addition to bryozoans and algae, as part biohermal limestones are present shells of mollusks, tubes of sea worms (Serpulidae). Upward along the stratigraphic section these limestones frequent change by algal-microbial ones. Limestones formed in certain paleogeographic conditions favorable to their development and universally marked coastlines of the Miocene seas.