Sedimentary Rocks
What are sedimentary rocks?
Rocks that form from pieces of other rocks that were eroded & weathered
What are igneous rocks?
Rocks that form from molten rock (magma) which is either ejected at the surface of Earth or cools off underground.
What are metamorphic rocks?
How are metamorphic rocks formed?
Rocks that have changed shape or composition due to intense heat and pressure.
Sediments are compacted.
What are ripple marks & what do they tell us?
Looks like waves; Created when sediment is moved by water or wind; Shows that water was once there or there was a lot of wind
Sedimentary Formation:
Rocks that are the result of the processes of weathering and erosion which are continually breaking down and rearranging them. Small rocks, fragments and organic remains that have been moved by water, wind or other agents of erosion are called sediment. Over a period of time, sediment is cemented together to form sedimentary rocks.
How are sedimentary rocks formed?
Sediments are placed in layers, Layers are compacted together, Minerals act as glue to harden the sediments
How are igneous rocks formed?
Rocks are heated enough to melt, Molten rocks eventually cools
What are foliated metamorphic rocks?
Rocks put under high pressure & spread in one direction; bands/layers are formed
What is cross-bedding & what does it tell us?
Form when sediment slides down a slope (hill); Shows that water was once there or there was a lot of wind
Igneous Formation:
Rocks that form from molten rock which is either ejected at the surface of Earth or cools off underground.
Rocks that form from molten rock which is either ejected at the surface of Earth or cools off underground.
What are clastic sedimentary rocks?
Created from other pieces of rocks; most common
What are extrusive rocks?
Lava/magma exits Earth and cools on the surface
What are nonfoliated metamorphic rocks?
What are foliated metamorphic rocks?
Rocks put under low pressure & spread equally; no bands/layers are formed
Rocks put under high pressure & spread in one direction; bands/layers are formed
What are mud cracks & what do they tell us?
Created when sediment dries up after soaking in water; Shows that water was near or the area went through wet/dry periods
Metamorphic Formation:
Rocks that have changed shape or composition due to intense heat and pressure
Rocks that have changed shape or composition due to intense heat and pressure
What are chemical sedimentary rocks?
Created when water evaporates and minerals crystallize
What are intrusive rocks?
Magma cools underground
What is regional metamorphism?
Occurs when a large area of land is exposed to extreme heat and pressure; usually creates foliated rocks
Looks like waves; Created when sediment is moved by water or wind; Shows that water was once there or there was a lot of wind
Form when sediment slides down a slope (hill); Shows that water was once there or there was a lot of wind
Created when sediment dries up after soaking in water; Shows that water was near or the area went through wet/dry periods
Extrusive Igneous (description):
Intrusive Igneous (description):
Foliated Metamorphic (description):
Nonfoliated Metamorphic (description):
Rocks that form when molten rock reaches the earth's surface and cools. Air and moisture cool the lava rapidly. The quick cooling doesn't allow the formation of large crystals.
Molten rock that cools before it reaches the surface hardens to become this type of igneous rock. Because it forms deep beneath Earth's surface, it has more time to cool and it develops large crystals.
Rocks where the individual mineral grains may recrystallize to form larger crystals that make parallel bands or lines in the rock. Form by heat and pressure.
Rocks where crystals combine and rearrange When heated under pressure) so they don't form any bands.
What are organic sedimentary rocks?
Created from remains of plants/animals
The rate of crystal formation in igneous rocks depends on the...
Speed of cooling
What is contact metamorphism?
Occurs when rocks are heated by magma/lava; usually create non-foliated rocks
Clastic Sedimentary (description):
Chemical Sedimentary (description):
Organic Sedimentary (description):
Sedimentary rocks that have been formed from the fragments of other rocks.
Sedimentary rocks that result from chemical deposits. Dissolved materials crystallize by evaporation or precipitation to form these rocks.
Rock that formed from the life processes of living organisms or the remains of the organisms.