kansan glaciation

The Kansan Glaciation (known in UK as the Anglian Glaciation and sometimes referred to as the Illinoian Glaciation, Elster glaciation in northern Europe and the Mindel glaciation in the Alps) was a very severe glacial period in the Pleistocene. The Kansan Glaciation is generally taken as covering the period between 410,000 and 380,000 years before the present, though with the increasing evidence that glacial maxima are actually quite short, its peak is not clearly known. It is considered that the Kansan Glaciation marks the absolute maximum extent of continental ice sheets in the Quaternary. The name, used generally only in North America, comes from the evidence that ice sheets reached as far south as Douglas County, Kansas, which is more than 500 kilometres further south than the limits of maximum glaciation during the Last Glacial Maximum. In Europe, ice sheets extended as far south as present-day Slovakia and London. Because the last glacial maximum has buried most evidence of the severe Kansan glaciation, establishing environmental conditions elsewhere during this period is very difficult and can be done only via oceanic studies. These, however, indicate that the jet stream during the Kansan glaciation might have been as much as five degrees further south than it was during the last glacial maximum. (This would place it over Sonora state in Mexico and over southern Morocco in Africa). These findings suggest very strongly that the Kansan glaciation would have had much greater effects on the distribution of flora and fauna than more recent glacial periods. Most especially, many small ice-free refugia in North America are likely to have been completely ice-covered during this period, whilst in West and Central Africa, and southern Australia, most of the hypothesised forest refugia of the last ice age are likely to have not been able to retain their forest cover. It is also probable that glaciers occupied much larger areas in mountains than they did at the last glacial maximum. (For instance, periglacial features in the Drakensberg suggest glaciation at some period in the Quaternary, but other evidence suggest the mountains were not glaciated during the last glacial). The Amazon rainforest, which retained a considerable portion of its present extent at the last glacial maximum, may have been constricted to a few refugia during the Kansan glaciation. These refugia have been shown to have the highest biodiversity as well as the wettest climate.

Anglian glaciation

The Anglian glaciation is a name for an ice age period which occurred between 450,000 and 300,000 years ago. The name is used by British geologists and archaeologists who named it after the region of East Anglia where most of the deposits it created have been found. It is a Pleistocene stage of the Quaternary period. It was a full glacial phase and its deposits directly overlie material from the preceding Cromerian interglacial and lie beneath those from the following Hoxnian interglacial It was formerly known as the Lowestoft glaciation.

Kansan Glaciation

Anglian glaciation

See also