Planktonic foraminifera are everywhere used as a tool for biostratigraphic purposes, but in some cases due to the unfavourable conditions they are not always present. Moreover these planktonic foraminifera are not always well preserved, oftenly indeterminable and undiagnostic. Thus another biostratigraphic tool is wise to be exposed.
Many investigations indicated that the benthonic foraminifera very useful in dating the sediment locally, beside the major use in the recognition of paleoenvironments. The ability to accurately determine environment is of fundamental importance in the oil industry since both hydrocarbon source rocks and reservoir rocks accumulate under rather restricted environmental condition.