Sub-Atlantic

Last of the five postglacial climate and vegetation periods of northern Europe, beginning c 1500 BC (according to pollen analysis, though radiocarbon dating says c 225 BC). It is a division of Holocene chronology (10,000 years ago-present). The Sub-Atlantic Interval followed the Sub-Boreal Climatic Interval and continues today. It is a subdivision of the Flandrian, thought to be wet and cold, a trend started in the preceding Sub-Boreal period. There was a dominance of beech forests and the fauna were essentially modern. During the Iron Age, pollen analysis shows evidence of intensified forest clearance for mixed farming. Sea levels have been generally regressive during this time interval, though North America is an exception.

A climatic sub-division of the Flandrian, originally supposed to be wet and cold, in contrast to the preceding SubBoreal period. The increased rainfall may be attested in Britain by a change in the peat stratigraphy of bogs (see recurrence surface). Godwin’s Pollen Zone VIII corresponds to the Sub-Atlantic in Britain. The start of Zone VIII was originally defined as the appearance of beech and hornbeam in southern England. However, this is of little use in the rest of Britain, where beech and hornbeam do not appear. Vegetation change of a different kind does, however, occur in many areas. During the Iron Age, at dates younger than the change in peat stratigraphy, a large number of pollen diagrams show evidence of intensified forest clearance. Many areas of Britain appear to have been cleared for the first time. These clearings appear mostly to have been permanent, and used for mixed farming.