Before Present
From Biocrawler, the free encyclopedia.
Before Present (BP) is a year numbering system, used for the far past times, relating dates to the year 1950. For example, 12,000 BP means 12,000 years before 1950. This is a commonly-used year numbering system in carbon-14 dating.
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Why 1950?
Scientists established 1950 as the benchmark date for the BP system because it is the year in which calibration curves for carbon-14 dating were established. 1950 also predates atmospheric testing of nuclear weapons, which altered the global balance of carbon-12 to carbon-14, which in turn altered the calibration curves for carbon-14 dating[1].
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See also
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References
- AD or BC? Questions at California State University, Los Angeles (http://vcourseware.calstatela.edu/VirtualDating/files/RC_3.html)
