Catastrophic floods
Now when you look around Yogi, you see a moat, in fact. There's this
little area that's actually been hollowed out and that's consistent with
the idea that late-stage flow from this flood deposit actually winnows out
the finds around the big blocks, which can no longer be moved by the flood
and creates a little moat around them. We saw that near Yogi and a few
other rocks as well. And finally, when you look off beyond the ridge, that
the Bookshelf is on in the Rock Garden, there's a depression that looks
like a little channel. And if you keep going in that direction there is
ridge and channel and ridge and channel and ridge and channel, and that
looked very like what we see on the catastrophic flood deposits where
late-stage drainage winnows out and creates smaller channels in this plain
deposit, deposited by the material in which the finds are carried away in
some channels and in other areas they are sort of kept by the larger rock
distributions. So those all sort of fit together and imply deposition by
this catastrophic flood.
Matt Golombek video
Matt Golombek audio