<P> An ice sheet is a mass of glacier ice that covers surrounding terrain and is greater than 50,000 km (19,000 sq mi), this is also known as continental glacier . The only current ice sheets are in Antarctica and Greenland; during the last glacial period at Last Glacial Maximum (LGM) the Laurentide ice sheet covered much of North America, the Weichselian ice sheet covered northern Europe and the Patagonian Ice Sheet covered southern South America . </P> <P> Ice sheets are bigger than ice shelves or alpine glaciers . Masses of ice covering less than 50,000 km are termed an ice cap . An ice cap will typically feed a series of glaciers around its periphery . </P>

Where do earth's large ice sheets now exist