Metamorphic

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Metamorphic Hydrothermal Rocks II
Photo Credit R. Weller
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Metamorphic Rock Classification
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Non- foliated Metamorphic Rocks

• Limestone -gt Marble
• Quartz sandstone -gt Quartzite
• Shale/Basalt -gt Horfels

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Marble - Metamorphosed Limestone
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Michelangelos David
Carrara Marble Quarry
Image source Ian Britton
Image Source The Digital Michelangelo Project
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Stirling Quartzite - 540 MyBP
Well preserved cross-bedding
http//digital-desert.com/death-valley-geology/sti
rling-quartzite.html
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Horfels - Contact Metamorphic Rock
Photo credit R. Weller
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Slate Outcrop - Antarctica
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Foliated Metamorphic Rocks

• Slate contains clays and other sheet silicates
• Phyllite dominated by muscovite mica
• Schist contains biotite, muscovite, amphibole,
  and garnet
• Gneiss alternating layers of qtz/fsp and
  biotite/amphibole

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Slate hand specimen
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Phyllite
NB Crenulation cleavage and silky luster
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Garnet Mica Schist
Garnet
Mica
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Gneiss
NB Banding Qtz Fsp Ferromagnesian minerals
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Crustal Metamorphism of Shale
Overburden increases with depth!
30 km thick
9 kbar pressure
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Scottish Barrovian Zones in Pelites
High Grade
Low Grade
Regional metamorphism and deformation related to
the Paleozoic Caledonide Orogeny (NA-EUR
collision). 13 km thick section. First described
by Barrow (1893).
From Gillen, 1982
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P-T-time Paths
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Convergent Margin Metamorphism Animation
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Basalt -gt Granulite -gt Eclogite Stability Fields
NaAlSi3O8 NaAlSi2O6 SiO2 albite
jadeite qtz
BASALT
ECLOGITE
CaAl2Si2O8 2(Mg,Fe)SiO3 Ca(Mg,Fe)2Al2Si3O12
SiO2 anorthite opx
garnet qtz

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Basalt to Eclogite
Garnet Pyroxene
Plagioclase Pyroxene Olivine
Photo credits USGS, A. Alden, Union College
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Regional Metamorphic Rocks - Summary
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Shock Metamorphism

• Related to impacts of objects on planetary
  surfaces (asteroids and meteorites).
• Deformation (metamorphism) is extremely rapid and
  transient.
• Achieve much higher peak metamorphic temperatures
  and pressures than commonly observed in
  terrestrial environments.
• Products include impact breccias, melts
  (tektites), and planer deformation features in
  quartz and feldspar.

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Meteor Crater, AZ
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Canyon Diablo Iron Meteorite
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Planetary Impact Structures
Apollo 11 Image The Moon
Galileo Image Ganymede
From http//neo.jpl.nasa.gov/neo.html
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Impact Simulation - Gravity Dominated Model
Comet Impact Body 1.5 g/cc 6 x 3 km
Simulation by James Richardson and H. Jay
Melosh, Univ. of Arizona
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Shock Metamorphism P/T Conditions
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PDS in Shocked Quartz
Planar Deformation Structures
From http//www.impact-structures.com/
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Plate Tectonics and Metamorphism

• Hydrothermal Processes
• Hydrothermal Activity at Divergent Plate
  Boundaries 
• Metasomatism
• Hydrothermal Rocks and Minerals 
• Sources of Water

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Ridge Crest - Hydrothermal Metamorphism
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Submarine Pillow Basalt Formation
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Active Black Smoker Video
Main Endeavor Hydrothermal Vent Field on the
Endeavor Segment of the Juan de Fuca Ridge at
4757' N, 12906' W. Video from the ROV Jason
obtained by J. Delaney V. Robigou, Univ. of
Washington.
From http//www.amnh.org/nationalcenter/expeditio
ns/blacksmokers/gallery.html
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Contact Metamorphic Aureole
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Hydrothermal Metamorphism - Intrusions
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Ore-bearing veins
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Vein Formation Animation
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Bingham Canyon copper mine, UT
Pit is 800 m deep 4 km wide
Mining began in 1863 40,000 kg of TNT used 60,000
tons of ore removed Disseminated ore deposit.
Only 0.6 copper by wt. Since 1904, 12 x 106
tons of Cu extracted.
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Convergent Margin Hydrothermal Metamorphism
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Hydrothermal Summary