Ice age
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An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages, and greenhouse periods during which there are no glaciers on the planet. Earth is currently in the ice age called Quaternary glaciation. Individual pulses of cold climate within an ice age are termed glacial periods, and intermittent warm periods within an ice age are called interglacials or interstadials.
An artist's impression of ice age Earth at Pleistocene glacial maximum
Haukalivatnet lake (50 meters above sea level) where Jens Esmark in 1823 discovered similarities to moraines near existing glaciers in the high mountains
Stages of proglacial lake development in the region of the current North American Great Lakes
Scandinavia exhibits some of the typical effects of ice age glaciation such as fjords and lakes.
Proglacial lake
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In geology, a proglacial lake is a lake formed either by the damming action of a moraine during the retreat of a melting glacier, a glacial ice dam, or by meltwater trapped against an ice sheet due to isostatic depression of the crust around the ice. At the end of the last ice age about 10,000 years ago, large proglacial lakes were a widespread feature in the northern hemisphere.
Argentinian proglacial lakes: Lago Viedma (middle), Lago Argentino (left) and Lago San Martin (right). Retreating glaciers are visible at the top.
Tarn—a proglacial lake impounded by the terminal moraine of the retreating Schoolroom Glacier in Grand Teton National Park, Wyoming
Lake Blåvatnet in Lyngen Alps, Norway located below Lenangsbreene glaciers and surrounded by several moraines formed during Younger Dryas and early Holocene
The Hubbard Glacier closed off the Russell Fjord from Disenchantment Bay in 2002 to cause the waters behind the glacier to rise 61 feet (19 m) over 10 weeks in a proglacial lake until they broke through.