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Pleistocene epoch

(Encyclopedia)Pleistocene epoch plīˈstəsēn [key], 6th epoch of the Cenozoic era of geologic time (see Geologic Timescale, tablegeologic timescale, table). According to a classification that considered its depos...

Ice Age

(Encyclopedia)Ice Age: see Pleistocene epoch.

glacial periods

(Encyclopedia)glacial periods, times during which large portions of the earth's surface were covered with thick glacial ice sheets. In the Pleistocene epoch, in the Carboniferous and Permian periods of the Paleozoi...

Agassiz, Lake

(Encyclopedia)Agassiz, Lake ăgˈəsē [key], glacial lake of the Pleistocene epoch, c.700 mi (1,130 km) long, 250 mi (400 km) wide, formed by the melting of the continental ice sheet beginning some 14,000 years ag...

Holocene epoch

(Encyclopedia)Holocene epoch hŏlˈəsēn [key] or Recent epoch, most recent of all subdivisions of geologic time, ranging from the present back to the time (c.11,000 years ago) of almost complete withdrawal of the...

Boucher de Crèvecœur de Perthes, Jacques

(Encyclopedia)Boucher de Crèvecœur de Perthes, Jacques də krĕvkörˈ də pĕrt [key], 1788–1868, French writer and archaeologist. He was the first to provide evidence that humans had existed in the Pleistocen...

Ice Age National Scenic Trail

(Encyclopedia)Ice Age National Scenic Trail: see National Parks and Monuments (table)national parks and monuments (table). ...

Baltic Shield

(Encyclopedia)Baltic Shield, the continental core of Europe, composed of Precambrian crystalline rock, the oldest of Europe. The tectonically stable region was not affected by the Caledonian, Hercynian, and Alpine ...

epoch

(Encyclopedia)epoch, unit of geologic time that is a subdivision of a period. The Pleistocene and Holocene epochs, for example, are divisions of the Quaternary period. Epoch is also used to describe a short length ...

Canadian Shield

(Encyclopedia)Canadian Shield or Laurentian Plateau lôrĕnˈchən [key], U-shaped region of ancient rock, the nucleus of North America, stretching N from the Great Lakes to the Arctic Ocean. Covering more than hal...