Patagonian Ice Sheet

Patagonian Ice Sheet

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[[image:Magellanglaciacion.jpg|350px|thumb|right|Map showing the extent of the Patagonian Ice Sheet in the [[Strait of Magellan]] area during the [[last glacial period]]. Selected modern settlements are shown with yellow dots. Note that the sea-level was much lower than shown in this picture.]] [[File:Puerto Williams, Chili.JPG|right|350px|thumb|During the last ice age the Patagonian Ice Sheet created the elongated and forested [[drumlin]]s seen south of [[Puerto Williams]], [[Chile]].]] The '''Patagonian Ice Sheet''' was a large elongated and narrow [[ice sheet]] that covered all of [[Chile]] south of approximately present-day [[Puerto Montt]] during the [[Last glacial period|Llanquihue glaciation]]. Some maps have the Patagonian Ice Sheet connected to the icecaps of the [[Altiplano]] by continuous glaciers all the way through the [[Andes]]. The [[ice]] sheet extended beyond the crest of the Andes into [[Argentina]], but because of the dryness of the climate it did not reach beyond present-day [[lake]]s such as the [[Yagagtoo]], [[Musters]], and [[Colhue Huapi]]. At its peak (about 18,000-17,500 years ago), the Patagonian Ice Sheet covered about 480,000 km² of land with an estimated ice-volume of more than 500,000 km³, of which about 4 % remains glaciated today in two separated portions known as the [[Northern Patagonian Ice Field|Northern]] and [[Southern Patagonian Ice Field]]s. The ice-volume reduction contributed to a global sea-level rise of about 1.2 meters. However, during the first glacial period at the beginning of the [[Pleistocene]] ice extended to the present-day Argentine coast. With each successive glaciation it is known that the ice has stopped further and further to the west, with [[aridity]] always serving as the decisive factor halting glacier spread: it is believed that the east-west [[precipitation (meteorology)|precipitation]] gradients during glacial periods were even steeper than the extremely steep ones of present-day [[Patagonia]]. Unlike the [[Laurentide Ice Sheet]] or the ice sheets of [[Northern Europe]], the Patagonian Ice Sheet did not cause major extinctions or loss of [[biodiversity]]. This is because the flora remaining to the north of the ice was isolated by the [[Atacama Desert]] and was able to [[speciate]] easily wherever suitable [[microclimate]]s occurred. In fact, most of the original [[Antarctic flora]] survives today on land occupied by the ice sheet. However, there are indications that during the last deglaciation (17,500 years ago), the rapid melting of the northernmost extension of the Patagonian Ice Sheet resulted in a dramatic release of [[freshwater]] to the adjacent ocean, decreasing its [[salinity]] and altering its circulation, resulting in significant ecological changes both locally and remotely. == See also == * [[Ice sheet]] * [[Northern Patagonian Ice Field]] * [[Southern Patagonian Ice Field]] * [[Katalalixar National Reserve]] * [[Geography of Argentina]] * [[Geography of Chile]] {{Andean glaciers}} {{coord missing}}