Hey, Faith: here in my portion of the Southwest I can show you some places - like Palo Duro Canyon near Amarillo or the Double Mountain Fork of the Brazos valley north of Rotan, Tx - where the formations look like one of those German cakes with a zillion layers. But these rock layers are in rust-red and white - iron-rich sandstone and gypsum. And there are truly thousands of layers exposed in places, and many more cored out of oil wells out here.
And these formations are also being formed very gradually today in some spots, like just off Interstate 20 east of Midland. There are large occasional lakebeds over there, that actually look lakelike a few times per decade when it rains noticeably. Most years these "playas" catch some windblown sand and dust. Right after a big thunderstorm they catch a big slug of water-borne sand and silt. But then, when the two-foot-deep water slowly evaporates, the lakebed picks up a coating of white gypsum (calcium sulfate) which falls out of solution as the water goes away. And the cycle repeats, building up perhaps a few inches each century. And a section through the bed looks just like the hundred-foot banded cliffs at Palo Duro or Rotan.
What mechanism will build that sort of layer cake in a single big flood? How do we alternate sand supply and nearly sand-free evaporation when everything is under water? Any speculations?