Unbelievable. Out of nowhere de-facto capitulation. Phil Claeys, a co-author of the new paper Scribd below, is a persistent and rather snarky critic of the Younger Dryas Boundary theory, see here:
Supposed chemical evidence has withered under scrutiny, says impact geochemist Philippe Claeys of the Free University of Brussels. Claeys and colleagues probed YDB samples—both his own from Europe, and others from West—for claimed traces of an impacter. The targets included iridium, the exotic element that first put researchers on the trail of the dinosaur-killer impact. In a December 2009 PNAS paper, Claeys and colleagues reported their results: nil. “The geochemical story is finished; it’s over,” Claeys says. “There is nothing, no meteoritic signal. No one I know of has come to their defense.” http://www.sciencemag.org/content/329/5996/1140.full September 3, 2010.
Phillipe — to his credit — apparently went a’lookin himself in the YDB, and what did he find?:
Our findings confirm, and in fact reveal more direct proof than the earlier studies, the existence of nanodiamond particles in the YDB layer.– Claeys, et. al.,PNAS, December, 2010
How about that? Look and ye shall find, huh, Phil?