Think about what you learned about sedimentary rocks. Why would ...

[Mr. Wonderful]

Think about what you learned about sedimentary rocks. Why would ancient cross-bedded sandstone
  beds, as seen in Zion National Park, Utah, be useful to geologists? What will be an ideal response?

Question 2

What is desert pavement, and how does it form? What will be an ideal response?

[cici]

Answer to Question 1

There are many things that can be learned from these rock layers. The sandstone is an ancient dune,
having a classic dune structure, so it tells geologists about the environment that was present at the time
the sands were deposited. The cross-bedding indicates the prevailing direction of the wind that formed
the sand dunes. If something is present in the dunes, some fossils or something that can undergo
radiometric dating, perhaps the age of the rock layer can also be determined. It is in this way that
geologists have pieced together the geologic history of the desert Southwest

Answer to Question 2

Desert pavement is a mosaic of close-fitting rocks found in the desert. Winds remove sand-sized
particles by deflation, leaving a surface of pebbles, cobbles, and boulders. Once desert pavement
forms, it protects the underlying material from further deflation.