Describe the two processes by which sediments are transformed ...

[kodithompson]

Describe the two processes by which sediments are transformed into sedimentary rocks. Which is the more effective process in the lithification of sand- and gravel-sized sediments?
 
  What will be an ideal response?

Question 2

What are the two groups of chemical sedimentary rock? Give an example of a rock that belongs to each group.
 
  What will be an ideal response?

[nothere]

Answer to Question 1

The two processes that transform sediments into sedimentary rocks include compaction and cementation. During compaction, as sediments accumulate through time, the weight of overlying material compresses the deeper sediments. As the grains are pressed closer and closer, pore space is greatly reduced. During cementation, the cementing materials are carried in solution by water that percolates through the pore spaces between particles. Over time, the cement precipitates onto the sediment grains, fills the open spaces, and acts like glue to join the particles together. Cementation is most effective process in the lithification of sand- and gravel-sized sediments.

Answer to Question 2

Chemical sedimentary rock can be inorganic chemical precipitate or made from biochemical sediments. Chemical sedimentary rocks include chert and travertine. Biochemical rocks include coquina, chalk, and diatomite.