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Introduction to Metamorphic Petrology Recommended Textbook: J.D. Winter (2001) An Introduction to Igneous and Metamorphic Petrology: Prentice Hall Pub.

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Presentation on theme: "Introduction to Metamorphic Petrology Recommended Textbook: J.D. Winter (2001) An Introduction to Igneous and Metamorphic Petrology: Prentice Hall Pub."— Presentation transcript:

1 Introduction to Metamorphic Petrology Recommended Textbook: J.D. Winter (2001) An Introduction to Igneous and Metamorphic Petrology: Prentice Hall Pub.

2 Scope of Metamorphic petrology  Metamorphic petrology is the study of the subsolidus changes that a rock undergoes when exposed to physicochemical conditions different from those prevailing near the surface of the Earth.  Metamorphism produces changes in mineral assemblages and textures that reflect re-equilibration of the rock to the new physicochemical conditions, i.e., minimization of the energy of the system.  Metamorphism is commonly isochemical (except for volatile components, e.g., H 2 O, CO 2 ). Where the system is open, the process is referred to as metasomatism.

3 Metamorphic Reactions Dehydration KAl 3 Si 3 O 10 (OH) 2 + SiO 2 = KAlSi 3 O 8 + AlSi 2 O 5 + H 2 O Decarbonation CaCO 3 + SiO 2 = CaSiO 3 + CO 2 Calcite Quartz Wollastonite Muscovite Quartz K-Feldspar Sillimanite Solid-Solid NaAlSi 3 O 8 = NaAlSi 2 O 6 + SiO 2 Albite Jadeite Quartz

4 Prograde and Retrograde Metamorphism Prograde Path Retrograde Path

5 Metamorphic Facies  A metamorphic facies is a domain of Pressure-Temperature Space  Metamorphic facies are defined by characteristic mineral assemblages specific to particular bulk-rock compositions

6 Conditions of Metamorphism and Metamorphic Facies

7  Contact or Thermal Metamorphism  Regional Metamorphism Orogenic Metamorphism Orogenic Metamorphism Burial Metamorphism Burial Metamorphism Ocean Floor Metamorphism Ocean Floor Metamorphism  Hydrothermal Metamorphism (Alteration)  Impact or Shock Metamorphism Types of Metamorphism

8 Contact or Thermal Metamorphism

9 Contact Metamorphism of Limestone Diabase Marble Limestone Marble Limestone

10 Pyroxene Plagioclase Garnet Thermally Metamorphosed Clastic Sediments

11 Orogenic Metamorphism

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13 Orogenic Metamorphism and differential stress  1 >  2 =  3  foliation and no lineation  1 =  2 >  3  lineation and no foliation  1 >  2 >  3  both foliation and lineation 11 Foliation (or Cleavage) and Lineation

14 Cleavage Bedding Onset of Orogenic Metamorphism Shale Slate Bedding

15 Phyllite Schist Progressive Orogenic Metamorphism

16 Gneiss

17 Anatexis

18 Anatexis or Partial Melting of Metasedimentary Rocks (Migmatites)

19 Burial Metamorphism

20

21 Subduction Metamorphism

22 Paired Metamorphic Belts Blueschist Facies Amphibolite Facies

23 Subduction Metamorphism

24 Ocean Floor Metamorphism

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26 Metamorphic Isograd Mapping (Index Minerals)

27 Metamorphic Index Minerals (Porphyroblasts) Staurolite (Fe,Mg) 2 Al 9 Si 4 O 23 (OH) Garnet (Fe,Mg) 3 Al 2 Si 3 O 12 Cordierite (Mg,Fe) 2 Al 4 Si 5 O 18

28 The Aluminosilicates Al 2 SiO 5 Andalusite Kyanite Sillimanite

29 Metamorphic Isograds and P-T Paths Barrow Zones Buchan Zones

30 Aluminosilcates as Indicators of Metamorphic Grade

31 Metamorphic reactions and metamorphic grade Muscovite + Quartz = K-feldspar + sillimanite + H 2 O Sillimanite Quartz K-feldspar Muscovite

32 Oslo: K-Feldspar- Cordierite Orijärvi: Biotite-muscovite 2 KMg 3 AlSi 3 O 10 (OH) KAl 2 AlSi 3 O 10 (OH) 2 (Ms) + 15 SiO 2 = 3 Mg 2 Al 4 Si 5 O KAlSi 3 O H 2 O Metamorphic Facies and Isograds

33 Facies Series

34 Pressure-Temperature-Time Paths


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