GEOL3045: Planetary Geology Lysa Chizmadia Earth-Moon System Lysa Chizmadia Earth-Moon System

Introduction  Earth is 3rd planet from the Sun  First with natural satellite  Largest planet in inner solar system  Diameter = 1.3 x 10 4 km  Highest density  5.52 g/cm 3  FeNi core 1/6  ’s volume  > Mars  Youngest surface  Weathering  Plate Tectonics  Earth is 3rd planet from the Sun  First with natural satellite  Largest planet in inner solar system  Diameter = 1.3 x 10 4 km  Highest density  5.52 g/cm 3  FeNi core 1/6  ’s volume  > Mars  Youngest surface  Weathering  Plate Tectonics Image from: Image from:

Plate Tectonics  Three types of plate boundaries  Divergent  Convergent  Transform  Explains distribution of e-quakes & volcanoes  Driven by convection  Primordial heat from  Accretion  Radioactive decay  Core crystallization  Three types of plate boundaries  Divergent  Convergent  Transform  Explains distribution of e-quakes & volcanoes  Driven by convection  Primordial heat from  Accretion  Radioactive decay  Core crystallization Image from: Image from:

Divergent Boundaries  AKA Spreading Center  AKA Rifts  Largest Mountain Chains in Solar System  Plates move apart due to eruption of lava  New lava = new oceanic crust  AKA Spreading Center  AKA Rifts  Largest Mountain Chains in Solar System  Plates move apart due to eruption of lava  New lava = new oceanic crust

Continental Rifting

Convergent Boundaries  AKA Destructive Boundaries  AKA Subduction Zones  Old oceanic crust dense & heavy  Heavy vs. light => subduction  Three Types:  Ocean-ocean  Ocean-continent  Continent-continent  AKA Destructive Boundaries  AKA Subduction Zones  Old oceanic crust dense & heavy  Heavy vs. light => subduction  Three Types:  Ocean-ocean  Ocean-continent  Continent-continent

Transform Boundaries  AKA Conservative Plate Boundary  Plates slide past each other  Fracture zones in Mid-ocean ridges  Strike-slips faults  Only e-quakes  No volcanoes  AKA Conservative Plate Boundary  Plates slide past each other  Fracture zones in Mid-ocean ridges  Strike-slips faults  Only e-quakes  No volcanoes

Hot Spots  Caused by mantle plumes  Plumes do not move, plates do  Leaves track of ocean islands  Bend at 40Ma  Major change in plate motion  Caused by mantle plumes  Plumes do not move, plates do  Leaves track of ocean islands  Bend at 40Ma  Major change in plate motion

Atmosphere & Hydrosphere  Atmospheric Layers  Water Cycle  Both act to weather surface  Surface is Young!  Atmospheric Layers  Water Cycle  Both act to weather surface  Surface is Young! Image from: Image from:

Weathering  Mechanical Weathering  Physical breakdown of rocks into smaller pieces  Chemical Weathering  Chemical reactions which act to dissolve minerals into aqueous ions  Presence of water near triple point  Mechanical Weathering  Physical breakdown of rocks into smaller pieces  Chemical Weathering  Chemical reactions which act to dissolve minerals into aqueous ions  Presence of water near triple point Image from: Image from: examples/triple.html

The Moon  Distance from   3.8 x 10 5 km  Orbit around   27.3 days (tidally locked)  Rotation (phases)  29.7 days  Density = 3.35 g/cm 3  Due to size & composition, considered a terrestrial planet  Surface Composition  Bright Highlands (82%)  CaAl 2 Si 2 O 8  Dark Maria (18%)  Basalt  Distance from   3.8 x 10 5 km  Orbit around   27.3 days (tidally locked)  Rotation (phases)  29.7 days  Density = 3.35 g/cm 3  Due to size & composition, considered a terrestrial planet  Surface Composition  Bright Highlands (82%)  CaAl 2 Si 2 O 8  Dark Maria (18%)  Basalt Image from: Images from: Near SideFar Side

Tides  Spring tide: when Earth, Moon & Sun aligned  Neap tide: Moon perpendicular to Sun  Spring tide: when Earth, Moon & Sun aligned  Neap tide: Moon perpendicular to Sun

Summary  Earth  Plate Tectonics  Divergent Plates  Convergent Plates  Transform Plates  Hot Spots  Complex Atmosphere  Hydrosphere  => Weathering  => Young surface  Surface composition  Oceans = Basalt  Continents = Granite  Earth  Plate Tectonics  Divergent Plates  Convergent Plates  Transform Plates  Hot Spots  Complex Atmosphere  Hydrosphere  => Weathering  => Young surface  Surface composition  Oceans = Basalt  Continents = Granite  Moon (Luna)  Terrestrial Planet  B/c size & composition  Low Density  Little or no FeNi core  Tidally locked to Earth  Always see same side  Pulls on oceans & crust  Surface composition  Anorthosite  Basalt  Old Surface  Heavily cratered  No weathering