introduction to what is petrology??? study of rocks (“petrosâ€‌) igneous & metamorphic...

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  • INTRODUCTION TO PETROLOGY

  • WHAT IS PETROLOGY???

  • WHAT IS PETROLOGY???

    Study of rocks (“petros”)

    igneous & metamorphic

    chiefly in the lithosphere

  • WHAT IS PETROLOGY???

    Study of rocks (“petros”)

    igneous & metamorphic

    chiefly in the lithosphere

    We will be dealing with hot rocks

    tell us about composition & history of lithosphere

    origin of rocks involves:

    transfer of heat (energy)

    movement of material

  • WHAT IS PETROLOGY???

    Study of rocks (“petros”)

    igneous & metamorphic

    chiefly in the lithosphere

    We will be dealing with hot rocks

    tell us about composition & history of lithosphere

    origin of rocks involves:

    transfer of heat (energy)

    movement of material

    LITHOSPHERE

  • THINK LIKE A PETROLOGIST

    what criteria do we use to distinguish rocks?

    what do we want to know?

    how do we answer these questions?

  • WHAT DO WE WANT TO KNOW?

    how do we make melts?

    what is melted, and where? what is the role of water?

    how do melts behave during solidification?

    what causes metamorphism?

    how are metamorphism & deformation related?

    how to rocks flow in the interior of mountain belts?

    how do tectonic rates compare to heat conduction rates?

    in what tectonic settings do these rocks form?

  • BASIS FOR UNDERSTANDING

    field methods & sample study (observation)

    theory, experiment & modeling (analytical)

  • THINGS TO CONSIDER

  • THINGS TO CONSIDER

    materials of earth

  • THINGS TO CONSIDER

    materials of earth

    physical conditions

    energy

    pressure

    temperature & heat

  • THINGS TO CONSIDER

    materials of earth

    physical conditions

    energy

    pressure

    temperature & heat

    relationship to tectonics

  • THINGS TO CONSIDER

    materials of earth

    physical conditions

    energy

    pressure

    temperature & heat

    relationship to tectonics

    EgyPT

  • EARTH INTERIOR

    Si -r

    ic h

    Fe -r

    ic h

  • EARTH INTERIOR

    Structure of Earth:

    Si -r

    ic h

    Fe -r

    ic h

  • EARTH INTERIOR

    Structure of Earth:

    chemical divisions

    core, mantle & crust

    Si -r

    ic h

    Fe -r

    ic h

  • EARTH INTERIOR

    Structure of Earth:

    chemical divisions

    core, mantle & crust

    mechanical divisions

    mesosphere, asthenosphere & lithosphere

    Si -r

    ic h

    Fe -r

    ic h

  • EARTH INTERIOR

    Si -r

    ic h

    Fe -r

    ic h

  • EARTH INTERIOR

    Core:

    Si -r

    ic h

    Fe -r

    ic h

  • EARTH INTERIOR

    Core:

    Fe-Ni metallic alloy

    outer core is liquid (no S-waves)

    inner core is solid

    Si -r

    ic h

    Fe -r

    ic h

  • EARTH INTERIOR

    Core:

    Fe-Ni metallic alloy

    outer core is liquid (no S-waves)

    inner core is solid

    differentiation at work!

    compositional separation within the planet (fractionation)

    Si -r

    ic h

    Fe -r

    ic h

  • EARTH INTERIOR

    Si -r

    ic h

    Fe -r

    ic h

  • EARTH INTERIOR

    Mantle:

    Si -r

    ic h

    Fe -r

    ic h

  • EARTH INTERIOR

    Mantle:

    peridotite (ultramafic)

    greatest V, m & E (moves & carries heat)

    Si -r

    ic h

    Fe -r

    ic h

  • EARTH INTERIOR

    Mantle:

    peridotite (ultramafic)

    greatest V, m & E (moves & carries heat)

    upper layer to 410 km (olivine to spinel)

    contains low velocity layer 60-220 km

    Si -r

    ic h

    Fe -r

    ic h

  • EARTH INTERIOR

    Mantle:

    peridotite (ultramafic)

    greatest V, m & E (moves & carries heat)

    upper layer to 410 km (olivine to spinel)

    contains low velocity layer 60-220 km

    transition zone between 410-660 km (spinel to perovskite)

    SiIV to SiVI

    Si -r

    ic h

    Fe -r

    ic h

  • EARTH INTERIOR

    Mantle:

    peridotite (ultramafic)

    greatest V, m & E (moves & carries heat)

    upper layer to 410 km (olivine to spinel)

    contains low velocity layer 60-220 km

    transition zone between 410-660 km (spinel to perovskite)

    SiIV to SiVI

    lower mantle has more gradual velocity increase

    Si -r

    ic h

    Fe -r

    ic h

  • EARTH INTERIOR

    Si -r

    ic h

    Fe -r

    ic h

  • EARTH INTERIOR

    Crust:

    Si -r

    ic h

    Fe -r

    ic h

  • EARTH INTERIOR

    Crust:

    mafic (magnesium + ferric) to felsic (feldspar + silica)

    rich in Si, Al, K, Na, Ca

    Si -r

    ic h

    Fe -r

    ic h

  • EARTH INTERIOR

    Crust:

    mafic (magnesium + ferric) to felsic (feldspar + silica)

    rich in Si, Al, K, Na, Ca

    two main types:

    oceanic

    continental

    + “transitional”

    Si -r

    ic h

    Fe -r

    ic h

  • EARTH INTERIOR

  • EARTH INTERIOR

    Oceanic crust:

  • EARTH INTERIOR

    Oceanic crust:

    thin: ~10 km on average

  • EARTH INTERIOR

    Oceanic crust:

    thin: ~10 km on average

    dense: ρavg = 3.0 g/cm3

  • EARTH INTERIOR

    Oceanic crust:

    thin: ~10 km on average

    dense: ρavg = 3.0 g/cm3

    relatively uniform stratigraphy (= ophiolite suite)

  • EARTH INTERIOR

    Oceanic crust:

    thin: ~10 km on average

    dense: ρavg = 3.0 g/cm3

    relatively uniform stratigraphy (= ophiolite suite)

    sediments

  • EARTH INTERIOR

    Oceanic crust:

    thin: ~10 km on average

    dense: ρavg = 3.0 g/cm3

    relatively uniform stratigraphy (= ophiolite suite)

    sediments

    pillow basalt

  • EARTH INTERIOR

    Oceanic crust:

    thin: ~10 km on average

    dense: ρavg = 3.0 g/cm3

    relatively uniform stratigraphy (= ophiolite suite)

    sediments

    pillow basalt

    sheeted dikes

  • EARTH INTERIOR

    Oceanic crust:

    thin: ~10 km on average

    dense: ρavg = 3.0 g/cm3

    relatively uniform stratigraphy (= ophiolite suite)

    sediments

    pillow basalt

    sheeted dikes

    massive gabbro

  • EARTH INTERIOR

    Oceanic crust:

    thin: ~10 km on average

    dense: ρavg = 3.0 g/cm3

    relatively uniform stratigraphy (= ophiolite suite)

    sediments

    pillow basalt

    sheeted dikes

    massive gabbro

    ultramafic rocks (mantle)

  • EARTH INTERIOR

    mafic rocks

    Oceanic crust:

    thin: ~10 km on average

    dense: ρavg = 3.0 g/cm3

    relatively uniform stratigraphy (= ophiolite suite)

    sediments

    pillow basalt

    sheeted dikes

    massive gabbro

    ultramafic rocks (mantle)

  • CONTINENTAL OCEANIC

  • EARTH INTERIOR

  • EARTH INTERIOR

    Continental crust:

    thicker: 20-90 km (avg = 35 km)

    less dense: ρavg = 2.7 g/cm3

    highly variable composition

    average = granodiorite

  • CHEMICAL DIVISIONS

  • divisions separate Earth into Si-rich and Fe-rich spheres, largely a result of early chemical differentiation based on a redistribution of matter, prior to major solidification, by density

    CHEMICAL DIVISIONS

  • divisions separate Earth into Si-rich and Fe-rich spheres, largely a result of early chemical differentiation based on a redistribution of matter, prior to major solidification, by density

    later, continued differentiation was (and is) mostly a result of melting and igneous process

    CHEMICAL DIVISIONS

  • divisions separate Earth into Si-rich and Fe-rich spheres, largely a result of early chemical differentiation based on a redistribution of matter, prior to major solidification, by density

    later, continued differentiation was (and is) mostly a result of melting and igneous process

    how do we know these things???

    CHEMICAL DIVISIONS

  • divisions separate Earth into Si-rich and Fe-rich spheres, largely a result of early chemical differentiation based on a redistribution of matter, prior to major solidification, by density

    later, continued differentiation was (and is) mostly a result of melting and igneous process

    how do we know these things???

    seismic velocity structure

    CHEMICAL DIVISIONS

  • divisions separa

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