Introducing Stratigraphy

Description

Metamorphic rocks are the third great type of rock found in the lithosphere. Originally of other types these rocks have been changed mainly by heat and pressure into new forms. This introductory guide explains metamorphic processes and the resulting rocks. Abstract: Metamorphic rocks are the third great type of rock found in the lithosphere. Originally of other types these rocks have been changed mainly by heat and pressure into new forms. This introductory guide explains metamorphic processes and the resulting rocks.  Read more... Content: Cover Title Contents Preface Acknowledgements 1 Introduction 1.1 What is metamorphism? 1.1.1 Protoliths 1.1.2 Changes to the minerals 1.1.3 Changes to the texture 1.1.4 Naming metamorphic rocks 1.2 Metamorphic rocks -- made under mountains 1.2.1 Mountain building 1.2.2 Directed stress, pressure and temperature in a mountain's roots 1.2.3 Exhumation of a mountain's roots 1.3 Metamorphism in local settings 1.3.1 Contact metamorphism 1.3.2 Hydrothermal metamorphism 1.3.3 Dynamic metamorphism 1.3.4 Shock metamorphism 2 The petrography of metamorphic rocks. 2.1 Quartzite and metapsammite2.1.1 Quartzite 2.1.2 Metapsammite 2.2 Metapelite 2.2.1 Slate 2.2.2 Phyllite and low-grade schist 2.2.3 Minerals and textures of medium-grade schist 2.2.4 The regional distribution of minerals in low- and medium-grade schist 2.2.5 Pelitic gneiss and migmatite 2.2.6 Metapelite in a contact aureole 2.2.7 The significance of Al2SiO5 for inferring metamorphic conditions 2.3 Marble 2.3.1 Pure calcite marble 2.3.2 Impure marble 2.3.3 Metasediments with mixed compositions 2.4 Metabasite 2.4.1 Six kinds of metabasite from regional metamorphic belts. 2.4.2 The ACF triangle for minerals in metabasites2.4.3 P-T stability of metabasites, and metamorphic facies 2.4.4 A metabasite made by contact metamorphism 2.5 Metagranite 2.5.1 Granitic gneiss and orthogneiss 2.5.2 Dynamic metamorphism of granite 2.6 Metaperidotite 2.6.1 Peridotite as a protolith 2.6.2 Anhydrous metaperidotite 2.6.3 Hydrous metaperidotite 2.6.4 Carbonate-bearing metaperidotite 2.7 Summary of metamorphic minerals and protoliths 2.7.1 Minerals and protoliths on an ACF triangle 2.7.2 Where do the six protoliths come from? 3 Interpreting mineral changes and textures3.1 Mineral stability, fluids, and partial melting 3.1.1 What is the meaning of stability? 3.1.2 How was the Al2SiO5 diagram obtained? 3.1.3 What kinds of metamorphic reaction produce water? 3.1.4 How much water is tied up in metamorphic minerals? 3.1.5 How does the water content in metapelites change with grade? 3.1.6 How are stable mineral assemblages in metapelites preserved? 3.1.7 Retrograde alteration and complete re-equilibration 3.1.8 Water in metabasites and metaperidotites 3.1.9 Fluids other than H2O. 3.1.10 Partial melting and the origin of migmatite3.2 Understanding metamorphic textures 3.2.1 A review of textures as a record of grain growth, strain, and multistage history 3.2.2 What makes grains grow? 3.2.3 Is time, like temperature, a factor in grain growth? 3.2.4 Does fluid have a role in grain growth? 3.2.5 What determines the shape of a grain? 3.2.6 Why do some minerals occur as porphyroblasts? 3.2.7 How does directed stress cause a foliated texture? 3.2.8 How does mylonite differ from cataclasite? 4 Aureoles, orogenies and impacts 4.1 Contact metamorphism.