Earth Science- Rocks
Sedimentary and Metamorphic rocks
Rocks formed when sediments are cemented or compacted once these sediments are deposited.
Constitutes about 5% of the Earths crust.
Many of these rocks also contain fossils.
Many of these rocks are important economically. (Energy resources)
Classification of sedimentary rocks
Can be classified as 1) detrital and 2) chemical
1.Detrital: Rocks formed mostly by mechanical weathering
Grouped based on particle size:
-Coarse (Ex . Conglomerate, breccia)
-Medium (ex. Sandstone)
-Fine (Ex. Siltstone)
-Very Fine (Ex. Shale
2. Sedimentary rock that is formed from chemical sediments, which are precipitated from solution.
Formed from chemical weathering
EX. Limestone, travertine, coal, coquina, rock gypsum, rock salt.
Metamorphic rocks
Rocks formed from metamorphism (transformation of one rock to another)
Metamorphism occurs when preexisting rock is subjected to temperatures and pressures unlike those in which it is formed.
Metamorphism
Slight changes low grade metamorphism) to Substantial changes ( high grade )
Shale turns into slate with heat and pressure.
2 setting of metamorphism
1)thermal ( contact)- rock is exposed to magma
2)Regional-tocks are exposed to high temperature pressure (mountain , building)
Agents in Metamorphism
Heat
Pressure stress)
Chemically active fluids( water vapor , carbon oxide)
Metamorphic Texture
Foliated- consists of layers (slate , schist and gneiss)
Non-Foliated-Lacks layers ( anthesite , marble
Landscapes fabricated by water
Water is everywhere on earth
Primarily located in the hydrosphere
975 of...
Please login to view the full essay...