Metamorphic Rocks Definitions Metamorphic Rock Meta Change Grk
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Metamorphic Rocks Definitions • Metamorphic Rock - "Meta"= Change (Grk) - "Morph"= form (Grk) -- a rock that has been changed from its original form ( parent ) by heat , pressure , and fluid activity into a new rock ( daughter ).
Heat Sources Include. . Magma • • Magma -- temperature of of magma -- composition of of magma Geothermal gradient • • Geothermal -- temperature increases with depth of of burial -- core of of Earth is is warmer than outer crust
Uniform Pressure vs Directed Pressure Uniform Pressure Lithostatic • • Lithostatic -- "Lithos"= rock, static= unchanged (pressure) -- uniform (aka non-directed) -- equal intensity from all directions by by rocks
Directed Pressure one direction of squeezing is much stronger than the others Minerals align themselves to reduce stress.
Types of Metamorphism Contact • • Contact -- caused by by igneous activity Dynamic • • Dynamic -- aka cataclastic -- associated with faults & & earthquake zones Regional • • Regional -- caused by by tremendous pressures associated with tectonic plate activity associated
Contact Metamorphism Igneous Intrusions • • Igneous -- size and type of of magma important mafic magma hotter than felsic >>mafic -- heat decreases away from magma forms aa zone of of altered country rocks called >>forms Aureoles Sometimes creates a metamorphic rock called a hornfels -in essence a “cooked” rock
Dynamic Metamorphism • • aka Cataclastic Metamorphism aka associated with Fault Zones associated -- Places where the Earth's crust ruptured -- Rock pulverized heat and pressure come from movement along the >> heat Fault Mylonite resultant rock is is known as as aa Mylonite • • resultant
Regional Metamorphism Most common form of of metamorphism • • Most caused by by large scale forces • • caused -- lithospheric plate collision covers very large areas • • covers -- metamorphic belts or or zones -- Zones are characterized by by Index Minerals Index form under specific temperatures and pressures >>form metamorphic facies >>metamorphic commonly associated with • • commonly -- shields: areas of crystalline rocks Shields andstable Mountains: of crystalline
Shields of the World
Metamorphic Textures Foliated • • Foliated -- Folios == page or or leaf-like -- rock has distinct banding or or layering often not smooth like in in sedimentary rocks >>often -- formed under directed pressure Non-foliated • • Non-foliated -- no no distinct layering character -- often aa massive crystalline texture -- formed under uniform pressures
Foliated Texture
Foliated Textures Slatey • • Slatey -- looks like blackboard dull surface >>dull -- smooth, thin layering -- breaks into flat slabs referred to to as as slatey cleavage >>referred -- no no mineral grains visible Phyllitic • • Phyllitic -- looks like waxed surface has aa "sheen" to to itit >>has -- may have little "waves" on on surface referred to to as as >>referred crenulations -- some small grains visible Schistose • • Schistose -- distinct bands of minerals -- visible grains mineral grains garnets, staurolites >>garnets, -- may have shiny appearance due to to mica minerals >>due Gneissic • • Gneissic -- larger grains -- may look like igneous rock -- may have crude banding intensely distorted >>intensely -- different minerals than schistose
Foliated MM Rocks slate phyllite schist gneiss MM MM Rocks that could form as as aa shale (sedimentary) parent rock is is exposed to increasing directed pressure and temperature
Non-foliated Rocks • Marble: - metamorphosed limestone Quartzite: • • Quartzite: -- metamorphosed quartz sandstone quartz
Environment of Formation- EOF look for specific minerals Map out where those minerals are found reconstruct T & P for given minerals Find a modern setting that has similar T & P using Uniformitarianism
Metamorphic Zones
Metamorphic Zones-Map Metamorphic
Metamorphic Facies distinctive metamorphic lithologies that occur in in well • • distinctive defined areas and named after the key rocks found defined
Metamorphic Zones • Metamorphism is common along most plate boundaries like this.
- Igneous vs metamorphic
- Igneous rock to metamorphic rock
- Drawing of rock cycle
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- Meta synthesis vs meta analysis
- How can one type of rock change into another type of rock?
- Rocks change due to temperature and pressure change
- Metamorphic rocks with a layered or banded look are called
- Chegg
- Characteristics of metamorphic rocks
- Slate vs shale
- Characteristics of metamorphic rocks
- Types of rocks metamorphic
- Dynamic metamorphic rocks examples
- Confining pressure vs directed pressure
- Metamorphic rocks in hawaii
- Granite parent rock
- Metamorphic phase diagram
- Formation of metamorphic rocks
- Characteristic of metamorphic rocks
- Classification of metamorphic rocks