Geology 100
Review information for Exam 1
Here is a list of topics that will hopefully guide your review for the exam.
The Earth.
Layers of the earth
Core/Mantle/Crust-names based on composition
Inner core/outer core/mesosphere/asthenosphere/lithosphere-names based on physical
properties
Heat transfer and models of convection in the mantle, Temp. and Pressure changes
Composition of the earth and space
H and He are most abundant in the universe-formed from big bang-decrease with
increasing atomic #.
Fe (iron) most abundant in the earth
Si and O most abundant in the crust + Na, K, Ca, Fe, Al, Mg, Ti =most of crust
Population and Growth Rates
Exponential growth rate of human population and the Doubling Time
Limiters on population growth: farmland and food, non-food resources, carrying capacity of the
earth?, large natural disasters and their effect on population
Plate Tectonics
Continental drift-evidence for drifting continents
Seafloor spreading-evidence for it: Sediment distribution, elevation, paleomagnetism
What causes the magnetic field of the earth? How is paleomagnetism useful for determining age
of rocks. Magnetic field reversals. What is magnetic inclination?
What are the main types of crust-What are the main differences between them?
Plate boundary types
For each main type, know the types of associated features, a couple of geographic
examples, and the effects of having different types of crust (oceanic and continental)
interact
Convergent-Subduction zones and trenches, Divergent-Mid-ocean ridges and rift valleys
Transform -Strike-slip faults
Earthquakes
Elastic Rebound Theory and stress
Seismic slip in the form of: creep or stick-slip behavior
Epicenter and Focus of the earthquake
Seismic Waves: Body Waves (faster): P waves (Primary, compressional, fastest), S waves
(secondary, shear, slower), Surface Waves: slowest
Why is it important to measure the difference in arrival time of the first P and S waves to
determine the distance to an earthquake?
What geometric technique do we use to pinpoint the location of an earthquake?
Magnitude of an Earthquake (ENERGY RELEASE). What are a couple of different scales we
use to describe magnitude?
Intensity of Earthquake-DAMAGE done in an earthquake. Why is the measure of intensity
necessarily qualitative? What geologic and geographic factors influence the intensity?
Earthquake Hazards
Ground motion, building collapse, landslides, liquifaction, Fire, Tsunami, Aftershocks
Tsunami. Generated from subduction zone earthquake or large undersea landslide
Tsunami hazards in Hawaii. Local generation vs. distant generation.
Identifying ancient Tsunami-examples from the Pacific NW: drowned trees (land drop), sand
sheet deposit.
Igneous Rocks and Volcanoes
Magma vs. Lava
Partial melting –addition of heat or decompression
Compositional variation in igneous rocks (Mafic/Intermediate/Felsic) can be generated by partial
melting/magma mixing/fractional crystallization-crystal settling.
Igneous rocks named on the basis of their composition AND their texture.
Felsic
Intermediate
Mafic
Ultramafic
Volcanic
Rhyolite
Andesite
Basalt
Plutonic
Granite
Diorite
Gabbro
Peridotite
Higher SiO2% --------
Lower SiO2%
Lower melting point--------Higher melting point
Higher viscosity magma---Lower viscosity magma
Volcanoes:
Volcano Types: Stratovolcanoes, Shield Volcanoes, Pyroclastic cones
Size, general composition, plate tectonic setting, and eruptive behavior of these volcanoes
Also, Lava Domes, Craters, and Calderas
Volcano products: lava, lava domes, pyroclastic (ash) fall, pyroclastic ashflow (nuee ardente,
ignimbrite), lahar
Hot spot volcanoes-tracing plate motion
Area of active volcanism at hotspot, volcanoes get older, lower as they move away from
volcano. Examples from Hawaii and Yellowstone.
Hawaiian Volcano Lifecycle: submarine stage/emergent/SHIELDBUILDING/ALKALIC/Erosional stage/rejuvenated stage/atoll stage/seamount-guyot stage
Predicting volcanic eruptions: precursor events-earthquake swarms, ground movement, small
phreatic eruptions (steam + some ash), gas emissions.
Relative size of eruptions Mt. St. Helens, Kilauea, Crater Lake, Yellowstone