For instance, even in the 1950s, when Willard Libby first developed the process, it was recognized that the scheme assumes that the level of carbon-14 in the atmosphere is constant.
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High-Precision Radiocarbon Age Calibration for Terrestrial and Marine Samples. Downloadbar von University of Washington This file contains additional information such as Exif metadata which may have been added by the digital camera, scanner, or software program used to create or digitize it.
For instance, creationist Walt Brown has pointed out inconsistencies in some radiocarbon dates of mammoths -- one part was dated to 40,000 years, another to 26,000 years (and wood surrounding it to 10,000 years), and yet another to between 15,000 and 21,000 years before the present epoch [Brown2001].
However, in the scientific results mentioned by Brown, the dates come from different mammoth specimens.
Also, at least one of these dates comes from a hide that had been soaked in glycerin, rendering the date invalid.