ANTHRO 103 Lecture Notes - Lecture 3: Dendrochronology, Paleomagnetism, Volcanic Rock
15 Sep 2016
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Document Summary
Relative dating methods: tell the age of one item in comparison to another. Absolute dating methods: specific age or age range of an object. Bio stratigraphic dating: fossils used to obtain dates & then correlated to other sites: fossils used are from taxa that. Varve analysis: yearly accumulation of sediments(dirt) at the bottom of glacier-fed lakes. The alignment of ferromagnetic particles in cooled volcanic rock is recorded: combination of relative & absolute dating. Radiometric methods: based on rates of decay from one isotope to another. Radiocarbon(14c) dating: wood, bone, & charcoal containing, date up to 50,000 years ago, 14c decays into 12c(isotopes) Potassium-argon(40k/40ar) dating: volcanic ash and lava, potentially infinite range (1. 25 billion half life, 40k begins to decay into 40ar.
