Archaic culture has to arrive some time ~ so why not 12000 years go BEFORE the Younger Dryas. We know Clovis went into deep decline, but other cultures that’d managed to penetrate all the way to South America didn’t.
What I’m looking at is the shift from the larger and heavier percussion made atlatl projectiles of the paleo period to the more refined and pressure flaked projectiles of the archaic period when bow’s were in use.