Chapter 1: Intro to Physical Geology

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Chapter 1 Intro to Physical Geology
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Historical VS. Physical Geology

• Geology - science of the Earth.
• Physical - processes and the materials.
• Historical - order of events, both physical and
  biological, that have occurred in the past.
• The past is the biggest clue to the present.

We do more physical geology is this class
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Physical Geology Topics

• Plate tectonics.
• Volcanism.
• Earthquakes.
• Landslides.
• Floods.
• Mountain-building.
• Shore erosion.
• Landscape formation.

• Rocks.
• Minerals.
• Air.
• Seawater.
• Soil.
• Sand
• Stream-flow
• Glaciations

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Geologists Use Other Sciences

• Chemistry minerals, rocks, water

• Physics - plate tectonics, volcanism,
  earthquakes.
• Biology -how life has changed fossils

• Meteorology streams, groundwater
• Oceanography seafloor spreading, shorelines

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James Hutton - (1726-1797)

• Father of modern scientific geology
• Proposed uniformitarianism, - everything moves
  slowly in repetitive, continuous cycles.
• Same processes today have been operating
  throughout history.
• Cycle of uplift, erosion, transport, deposition,
  solidification into rock, and renewed uplift
  takes a LONG TIME.
• Earth is 4.55 billion years old.

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The Earths Interior

• Earth has 3 main parts
• Core center, densest part, made of iron
  nickel.
• Mantle - surrounding the core.
• Crust - surrounding the mantle, thinnest and
  outermost
• But of course, it just cant
• be that simple. There are
• sections to sections and more
• names to learnsmiles

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The Core more detailed

• Inner core
• High temp High pressure solid iron
• Outer core
• Liquid iron

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The Mantle more detailed

• Lithosphere
• outer 100 km, some crust
• rocks cooler, more brittle rigid
• Asthenosphere
• 100 to 350 km
• hot, weak, plastic rocks
• ductile, little strength, and easily deformed
• Mesosphere
• between asthenosphere outer core
• core-mantle boundary 50000C.

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How do we know about the core mantle?

• Measure earthquake waves through Earth
• Waves travel different speeds in solids vs.
  liquids
• Compare P S types of waves
• Can P waves go through solids? Liquids?

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The Crust more detailed

• The crust is not uniform.
• oceanic crust about 8 km thick, more dense
• continental crust about 45 km thick, less dense

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Important Cycles

• Hydrologic cycle
• Water changing forms and locations in
  hydrosphere.
• Rock cycle
• Rock formed, changed, decomposed, and reformed by
  internal and external forces.
• Tectonic cycle
• Movements of plates of lithosphere internal
  processes of Earths deep interior that drive
  plate motions.

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The Rock Cycle

• Rock - natural, nonliving, solid mixture of
  minerals
• Rock cycle describes all the processes by which
  rock is
• Formed.
• Transported.
• Decomposed.
• Reformed.
• 3 rock families
• Igneous rock - cooling and solidification of
  magma
• Sedimentary rock - formed from deposits of
  sediment
• Metamorphic rock - formed by pressure heat on
  existing rocks

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Plate Tectonics

• Tectonics study of the movement and deformation
  of lithosphere.
• Plate tectonics theory lithosphere is cracked
  in about a dozen large pieces that constantly
  move

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The Tectonic Cycle

• Earth releases heat (from core)
• Hotter magma rises cooler sinks - convection
• Helps maintain constant internal temp
• Convection currents circulate in mantle moving
  plates
• Magma rises forms new oceanic crust at
  mid-ocean ridges.
• Plates collide and either sink at trenches or
  build mountains
• Lifetime of oceanic crust is shorter than
  continental crust.

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Results of Plate Tectonics

• Plate movements and interactions generate
• Earthquakes.
• Volcanism.
• Mountain-building.
• etc.

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Whats it called

• in Geology, when everything moves slowly in
  repetitive, continuous cycles?

uniformitarianism