THE BEGINNING OF THE ICE-AGE IN EUROPE AND ITS MAJOR SUBDIVISIONS

The time range of the Quaternary is discussed in terms of the view that this period is essentially the one in the Earth's history in which during certain intervals inland ice developed in the northern hemisphere. This process first became evident about 2.3 Ma BP. Since then, the Quaternary thus defined has witnessed many climatic variations. Although for practical reasons it is not feasible to assign the status of `stage' to each distinctly warm or cold phase, climatic change is nevertheless the most appropriate basis for world-wide correlation. It seems possible to use both climatic change and other correlation parameters to arrive at a practicable subdivision of the Quaternary Period into stages. Before about 1 Ma, vegetational succession during interglacials in western Europe differed from that seen in later times. A possible cause for this divergence is discussed. In the later part of the Quaternary (after about 1 Ma) two distinct types of warm-temperate intervals occurred: one associated with high sea-levels and an oceanic climate, the other showing lower sea-levels and a cooler and more continental climate. The difference between these two types is shown by comparison of the distribution of Abies during these time intervals.