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Comment: 06:03 - 07:05 (01:02)
Source: Annenberg/CPB Resources - Earth Revealed - 17. Sedimentary Rocks: The Key to Past Environments
Keywords: "Walter E. Reed", "sedimentary rock", "clastic sediment", compaction, cementation, "chemical precipitation", "pore space", packing, distortion
Our transcription: The process which converts loose clastic sediment into solid sedimentary rock is known as "lithification", from the Greek "lithos" meaning stone.
The first mechanism is one of simple compaction, the weight of the overlying sediments squeezing down grain by grain causing the grains to ultimately rearrange so that they get into close packing.
And finally distortion, and perhaps solution of the grain, so that ultimately you have a very tightly packed assemblage of sedimentary grains.
At the same time there may very well be chemical precipitation within the pore space, and that's called -- there's two terms that are used here -- but the best term for that is "cementation."
These two processes acting in concert go to make a loose sediment into a hard rock.
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