Lec 6 - Sed Rocks and Sed Strs - REVIEW LEC 6 SEDIMENTARY...

REVIEW
The Rock Cycle shows that the sediments that form sedimentary rocks are the products of
mechanical and chemical weathering of prior: igneous rocks, metamorphic rocks or older
sedimentary rocks.
Sedimentary rocks contain evidence of the environments in which their sediments were
transported (by water and wind) and deposited. They often contain fossils.
Sediments are turned into rock by a process called Diagenesis . This includes:
• Recrystallization – forming more stable minerals from less stable ones
• Lithification – “making rock”
o Compaction – “squozing” sediment grains together
o Cementation – usually calcite (CaCO
3
), but also silica and iron oxide
Sedimentary Rocks are classified by:
• Detrital Sedimentary rocks by grain size
• Chemical Sedimentary rocks by composition – e.g. CaCO
3
, Ca,MgCO
3
Be able to identify the following sedimentary rock types in hand sample:
• Detrital Sedimentary Rocks