There are several points of view on the conditions of slab formation. One group of researchers sees the main cause of layer formation in geotectonic fluctuations of the Earth's crust, which control the process of sediment accumulation. Other researchers consider the main cause of layer formation to be a change in the conditions of sediment formation as a result of changes in the physical-geographical regime; at the same time, they do not attribute significant importance to the geotectonic factor.