Anthropology 2229F/G Lecture Notes - Lecture 14: Standard Deviation

• School: Western University
• Department: Anthropology
• Course: Anthropology 2229F/G
• Professor: Christopher Ellis

Document Summary

Assumes plants gain carbon randomly from the atmosphere. Plants can be biased for/against certain isotopes of carbon. C-14 molecules move more quickly and are taken in preferentially by plants: e. g. corn (maize), millet: take in more radiocarbon than is in the atmosphere. Still probably the most reliable technique that we have today. Recent fluctuations of the earth"s magnetic fields, cosmic rays and glaciation can be corrected for. Date objects of known ages to see what the difference is and correct the date by taking it into account. Farther back in time we go, the radiocarbon dates are underestimating the age by about 2000 years: but differences are systematic, can fix the date based on the systematic deviation. Called correction factors: calibrated radiocarbon dates: date corrected to calendrical dates. Because of mixing problems in the ocean, we don"t get a very accurate date, but we can correct for it.