[Aztlan] Lake cores do not show YD impact evidence

[E.P. Grondine]

Buenos Dias - 

http://eco.confex.com/eco/2009/techprogram/P20277.HTM

Given the other findings, my guess is that given the difficulty in locating the very fine YD strata, if you are working at a site with significant water activity, the strata may not show up with enough detail to be identified.

E.P. Grondine
Man and Impact in the Americas