Before the present
See also: BP, Present
The expression “ before the present ”, or “ Present Before English ” (shortened in BP ), is used in Archéologie to indicate the expressed ages of number of Année S counted towards the past as from the year 1950 of the Gregorian Calendrier. This date was fixed arbitrarily like year under review and corresponds to the first tests of Carbon dating.
The mention “before the present” or “BP” generally applies to the dates obtained by methods of absolute Datation, like the dates carbon-14 but also at the dates obtained by other methods (Thermoluminescence, uranium-thorium, etc) for older periods (Paléolithique average inferior and ).
For the very old periods, even for the geological periods former to the appearance of the man, the BP mention is generally implied: the figures are incompatible obviously with an age after J. - C. and the difference between a BP age and an age before J. - C. is not significant compared to the margins of error obtained for the periods in question.
For the recent periods of Prehistory (Épipaléolithique, Mesolithic, Neolithic) and for the historical periods, it is possible to correct the inaccuracies of the dates obtained by the method of carbon-14, “to gauge them”. The gross profits are expressed in BP years but the results obtained after calibration are expressed in calendar years before J. - C.
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