No. 41: Sep-Oct 1985
About a decade ago, considerable controversy erupted when some obviously old human skeletons were dated at 37,000, 44,000, and even 70,000 BP by a new dating technique called Aspartic Acid Racemization (AAR). Conventional radioactive dating had put all of these skeletons at well under 10,000 BP, well within bounds of the Bering Strait migration hypothesis. The early AAR dates were thus at odds with current archeological thinking and, in addition, very encouraging to those who believed that humans occupied North America long before 10,000 BP. J.L. Bada, a proponent of AAR dating, now states that the controversial AAR dates were based on calibration skeletons which had been erroneously dated by radioactive methods. It seems that AAR dating requires an accurately dated reference skeleton. With the reference skeleton dates now known to be incorrect, Bada had to recalibrate his AAR dating scheme. The reference skeletons were therefore redated using a more accurate radioactive technique. All of the incredibly ancient skeletons have now been redated by AAR methods using the revised reference skeletons. The 37,000 BP date now becomes a reasonable 5,100 ± 2000 BP figure. The AAR dating crisis seems to be over. All anomalies have been expunged.
(Bada, Jeffrey L.; "Aspartic Acid Racemization Ages of California Paleoindian Skeletons," American Antiquity, 50:645, 1985.)