CATEGORY: chronology DEFINITION: A series of cold climatic phases in northwestern Europe, during a time when the North Atlantic was in almost full glacial condition. Dryas I was c 16,000/14,000 BP, Dryas II (Older Dryas) was c 12,300-11,800 bp, and Dryas III (Younger Dryas) was c 11,000-10,000 bp. It is named after a tundra plant. . The increasing temperature after the late Dryasperiod during the Pre-Boreal and the Boreal (c 8000-5500 BC, according to radiocarbon dating) caused a remarkable change in late glacialflora and fauna.
SYNONYMS OR RELATED TERMS: Younger Dryas event CATEGORY: chronology DEFINITION: A stadial of the Weichselian cold stage, dated to between 11,000-10,000 bp. The last glacial recession (13,000-6,000 years ago) was interrupted by this sharp advance. It takes its name from a tundra plant called Dryas octopetala, fossil remains of which are common in deposits of the stadial. It was most evident around the North Atlantic and coincided with an apparent temporary diversion of glacial meltwater from the Mississippi River to the St. Lawrence drainage system. It has been postulated that this discharge of cold, fresh water disrupted the Atlantic Ocean circulation system that warms the North Atlantic.
CATEGORY: chronology DEFINITION: The closing stages of the Pleistocene Ice Age, when the glaciers had begun their final retreat and when much of northern Europe was tundra. This period lasted from c 13,000-8500 BC. The substages in northern Europe are the Oldest Dryas (13,000-10,450), the Bølling oscillation (10,450-10,050), the Older Dryas (10,050-9850), the Allerød oscillation (9850-8850), and the Younger Dryas (8850-8300). Cultures of the Late Glacial period include Ahrensburgian, Creswellian, Federmesser, and Hamburgian.
Loch Lomond stadial
SYNONYMS OR RELATED TERMS: Younger Dryas CATEGORY: chronology DEFINITION: A widespread but short interval of renewed glacialactivity and cold climatic conditions in the British Isles. This event occurred about 11,000 years ago, some 2,000 years before the dissipation of the ice sheet. It is a stadial of the Devensian cold stage during which small glaciers were formed in the high mountains of Wales and the Lake District and an icecap was formed over the highlands of Scotland. The Loch Lomond stadial may be correlated with Godwin's Pollen Zone III and the Younger Dryas (Scandinavia).