ARCH 100 Lecture Notes - Homo Erectus, Upper Paleolithic, Hand Axe
12 Sep 2012
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Document Summary
Picture this as a gradual expansion of ecological territory, rather than a footrace across continents. Most dates you will see for early hominins come from dating the volcanic deposits that are deposited above or below the fossil beds. Lucky for us that east africa (and many other important fossil sites) have volcanic activity. Radioactive 40k atoms decay at steady rate, forming 40ar in rock. When volcano erupts, argo-40 escapes as gas, resetting this clock. 1936 find of a homo erectus skullcap. In 1990s researchers returned, collected volcanic pumice from same context, dated it to 1. 8 mya using argon-argon dating (a more accurate variation on k-ar dating) Argument is partly about whether the volcanic event occurred much earlier, redeposited sediment (?) Ongoing excavations since 1991 in medieval village. Paleomagnetic dating of several volcanic ash falls indicate 1. 7-1. 8 mya. Now have four craniz, parts of five postcranial skeletons (found 2006)
