GEOS 1004 Lecture Notes - Lecture 22: Permafrost, Clovis Culture, Lake Turkana
8 Mar 2018
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Document Summary
We are in an (cid:498)interglacial warm(cid:499) period now. Homo sapiens have existed for ~200 thousand years; they experienced 2 ice ages in their history (20 and 120 ka). What was it actually like during these ice ages (and how do we know): ice sheets, glaciers, moraines; glacial debris piled up in ridges or linear mounds (drumlins) 8 november, 2017: glacial deposits till; poorly sorted rubble, kettles - lakes and depressions made by erosion, melting ice, eskers - subglacial river channels, erosion by ice; bedrock striations. 8 november, 2017: (cid:498)steppes(cid:499) grassy, windswept, dusty plains, different ecosystems; e. g. forests, altered drainage networks, more lakes, big floods. During the 1st ice age, africa (where the people were) was cooler but drier; cycles of prolonged drought; hard times for early humans. Early humans responded in three ways: retreat to refugia high elevations, river banks. Lake turkana, lake victoria, south african caves: innovate.
