WHY DO U DO THIS TO US MS DEFALCO WHY

Chemical/hydrothermal metamorphism

*Hot water is introduced to the recrystallizing •Rock is able to change the chemical composition of the rock •Heat and pressure change the temperature of crystallization and introduces new element(s) into the rock - found at divergent

Phaneritic Texture

- Coarse grained - Mineral grains easily visible - Several mm in size or larger - Occurs when cooling takes place over a longer period of time allowing for minerals to congregate together

Aphanitic Texture

- Fine grained texture - Mineral grains smaller than 1mm - Need hand lens or microscope to see minerals - Occurs when cooling takes place over a shorter period of time so minerals do not congregate together

Porphyritic Texture

- Formed in dual process (quick cooling for part of crystallization and slow cooling for the other) - Large grain sizes embedded in fine grains - Occurs when plutonic magma beings to cool and is suddenly uplifted higher in the crust ( closer to surface )

Vesicular Texture

- Formed when rock contains high concentrations of gases - Cooling is rapid so not all of the gas escapes and bubbles ( vesicles ) are preserved - Example: Pumice - Extrusive****

Intrusive

- Rock Inside the Earth - Plutonic - Formed from magma - Cools slowly - Large grains

Extrusive

- Rock outside the Earth - Volcanic - Formed from lava - Cools quickly - Small or no grains

Kimberlites

- Type of intrusive rocks that contain valuable minerals and ore deposits like diamonds.

Vitreous Texture

- cooling occurs rapidly -occurs during eruptions - Obsidian = volcanic glass - Extrusive

Sedimentary Rock Formation Process

1. Weathering - rocks break down into sediments 2. Erosion - Rocks are transported by the wind or water/ice 3.Deposition/Sedimentation - small pieces of rock are deposited/added to the land due to the slowing down of water, wind and ice - In deposition, the heaviest and largest sediments settle out first and the smallest settle out last - Known as sorting 4. Compaction - pressure causes rock to compact ( squeeze together ) 5. Cementation - water and minerals causes the compacted sediments to cement together - Compaction and cementation are also known as lithification

Regional Metamorphism

•Protolith comes under pressure and strain due to movement of the plates • Usually also includes heat -Occurs during mountain building due to compression of two plates (can be either continental or oceanic convergence) - basically o-o or o-c

Contact Metamorphism

•Protolith recrystallizes due to the presence of a magmatic pluton near the rock •Heat from the magma can result in either a physical or chemical change in the rock •Recrystallization can occur - physical change •New minerals can be introduced to the rock - chemical change - found at hot spots and divergent

Dynamic metamorphism

•Result of very high shear stress along fault zones •Occurs at relatively low temperatures -found at all convergent and transform