1. Chapter 1: Intro to Physical Geology

2. 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

3. Physical Geology Topics
Plate tectonics.
Volcanism.
Earthquakes.
Landslides.
Floods.
Mountain-building.
Shore erosion.
Landscape formation.
Rocks.
Minerals.
Air.
Seawater.
Soil.
Sand
Stream-flow
Glaciations

4. 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

5. 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.

6. The Earth’s 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 can’t
be that simple…. There are
sections to sections and more
names to learn…smiles

7. The Core – more detailed
Inner core
High temp + High pressure = solid iron
Outer core
Liquid iron

8. 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.

9. 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?

10. 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

11. Important Cycles Hydrologic cycle: Rock cycle: Tectonic 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 Earth’s deep interior that drive plate motions.

12. 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

13. 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

14. 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.

15. Results of Plate Tectonics
Plate movements and interactions generate:
Earthquakes.
Volcanism.
Mountain-building.
etc.

16. uniformitarianism What’s it called…
in Geology, when everything moves slowly in repetitive, continuous cycles?
uniformitarianism