CLIMATIC FLUCTUATIONS IN THE MIDDLE LATITUDES OF THE NORTHERN HEMISPHERE ACCORDING TO THE STUDY OF CAMPANIAN PLANKTONIC FORAMINIFERA

To reconstruct the climatic fluctuations that occurred in the middle latitudes of the Northern Hemisphere in the Atlantic Ocean in the Campanian Age, the systematic composition of the shells of planktonic foraminifera was studied from core samples from seven deep-water drilling holes. The identified foraminiferal assemblages are assigned to two types (boreal and intermediate) and one subtype (warm boreal) thanatocenosis. On the basis of their spatial distribution, the position of climatic zones for sections of the early, middle, beginning and end of the late Campanian was determined. Different climatic zones were characterized by different types of water masses. Within the studied water area, during most of the studied age interval, two climatic zones were developed: intermediate and boreal. In the Early and Middle Campanian, the boundary between them was in the southern part of the region under consideration. At the beginning of the late Campanian, this border sharply shifted to the north. A short-term Late Campanian warming began. At the end of the late Campanian, the temperature dropped sharply. An intermediate type of thanatocenosis has not been identified. Even in the southernmost part of the water area, the warmboreal subzone prevailed. The obtained reconstructions are confirmed by our own and published data of oxygen isotope analysis.