Please enable JavaScript.
Coggle requires JavaScript to display documents.
Metamorphism - Coggle Diagram
Metamorphism
Key terms
Granoblastic
Similar sized crystal texture
Slate with chlorite
Marble with calcite
Hornfels with cordierite/quartz/andalusite
Gneissose
Parallel mono-mineralic bands
High grade metamorphism
Root of the continental crust
Regional metamorphism
Porphyroblastic
Large metamorphic crystal in a groundmass of smaller crystals
Schist with garnet
Spotted shale with chiastolite andalusite
Slaty cleavage
Foliation caused by the alignment of chlorite
Low grade metamorphism
In an accretionary prism
Regional metamorphism
Shistosity
Foliation caused by the alignment of mica
Medium grade metamorphism
In the continental crust
Regional metamorphism
Augen
Eye like structure
Garnet in Schist
Foliated
Pressure involved
Regional metamorphism
Schist
Slate
Gneiss
Coarse grained
Sustained period of high temp metamorphic recrystallisation
3mm
Non foliated
No pressure involved
Contact metamorphism
Marble
Hornfels
Spotted shale
fine grained
Parent rock was fine grained as well
Low temperature metamorphic recrystallisation
<0.1mm
Metamorphic facies
Different temps
75*c
Depth of 2km
Diagenesis
Shale
No facies
150*c
Depth of 5km
Low grade regional metamorphism
Slate
Zeolite facies
250*c
Depth of 7km
Phylite
Green schist facies
Medium grade regional metamorphism
350*c
Depth of 10km
Medium grade regional metamorphism
Schist
Green schist facies
600*c
Depth of 15 km
High grade regional metamorphism
Gneiss
Amphibolite facies
650*c
Depth of 18km
High grade regional metamorphism
Migmatite
Granulite facies
800*c
Depth of 25km
Magmatism/melting
Granite
No metamorphic facies
Changes at a subducting slab
Zeolite
Blueschist
Ecologite
Metamorphic dewatering
Changes at a continental collision boundary
Zeolite
Greenschist
Amphibolite
Granulite (small portion)
Magmatism
Contact metamorphism
Hornfels facies
Metamorphic grade
Contact Metamorphism
Between 0 and 1 kbars of pressure
Medium grade of shale makes spotted rock
High grade of shale makes Hornfels
Contact metamorphism of orthoquartzite
Marble
Metaquartzite
Regional metamorphism
Low grade
Temps between 150-250*c
Pressures between 1.8 and 2.8 kbars
Slate
Medium grade
Temps between 250-520*c
Pressures between 2.8-6 kbars
Lower is phylite
Higher is schist
High grade
Temps between 500-650*c
Pressures between 6-11 kbars
Lower is gneiss
Higher is migmatite
Other processes
Temps above 650*c and pressures above 2.5 kbars
Partial melting curve of wet granite
Conditions where igneous rocks can start to reform
Melting of metamorphic rock
Temps below 150*c and pressures above 2 kbars
Conditions not found in crust
Minerals reactions
Reaction series
Chlorite
Muscovite
Biotite
Garnet
Kyanite
Silliminite
Feldspar
Increase in pressure and heat causing changes in minerals formed
Integrated metamorphism
Where rock within a mineral cannot change before conditions change
The mineral/rock in the inclusion has different melting/metamorphic temp needed for alteration
Metamorphism is incomplete