Nipper, sorry to jump in and harsh your mellow on this one, but let's look at the forest which you have missed for the tree of the Coconino sandstone.
The Grand Canyon is a MILE DEEP in places. That means that a MILE DEEP of sedimentary rocks on top of igneous and metamorphic rocks had to have been laid down.
Now, let's look, rather than at the Coconino, but at the VISHNU formation at the bottom of the Grand Canyon.
This is a very
hard and resistant rock made up of ignoeous and metamorphic rocks. Do you know how hard it is to weather away granite, which is represented in the Vishnu? Go to your local cemetary to the oldest granite tombstone and tell me how "weathered" it looks to you.
Let's go back up to the Coconino sandstone. Now remember the Coconino looks the way it does (blocky) because it is a
resistant sandstone which means it is harder to weather than the rocks around it.
Note how the Coconino stays blocky while the ones above and below weather more easily.
Here's a picture from the Coconino from a website:
This looks an awful lot like
dune crossbedding to me. I could be wrong. Surely there may be some discussion of it.
The grains of the Coconino also appear to be
frosted (
Source). Why is this important? Well one of the hallmarks of
aeolian deposits like sand dunes is FROSTING of the grains:
Like these, they tend to look, well, frosted. From being hammered against other grains.
A polished texture is commonly observed on grains which have been transported by water, and correspondingly are typically rounded. Frosting is produced by collision with other sand grains and is commonly observed in aeolian sands.(
SOURCE)
The sand grains that make up the Coconino are
well rounded and
very well sorted (ie they are about the same size) which are very much like the sand grains we find in dunes forming today.
Here's what modern sand dune cross-bedding looks like:
(
Source)
Now certainly we can find some features of cross bedding in non-aeolian structures, but apparently most geologists seem to feel that these structures in the Coconino are more likely sand-dune deposits.
But even if it is the product of "Sand waves" under water. That's a LOT of sand. And it only took a
year to deposit it complete with structures like cross-bedding, AND have it cemented and compacted as well as the rocks above it,
AND THEN ERODED OPEN BY THE FLOOD? (Remember the Flood would have had to cut through a
resistant sandstone which remained as a solid BLOCK rather than crumbling like the softer rocks above and below it.
Quite a few hoops to jump through when there's a much simpler answer.
