Physical Geology

GEOL 101 - Exam 1 Review

Study hints

Study, study, study, study!

The most important activity for you to do to prepare for examinations is read and understand your class notes and required textbook. You should be able, without referring to your notes, to answer all of the questions in this study guide.

Make sure that you are prepared to make connections between major concepts.

For reinforcement of the class notes, refer to the reading in your textbook. I will not expect you to have memorized every detail presented in the book, but your level of comprehension will increase with exposure to the reading.

Earth's Differentiation

During earth's formation, everything melted and the heaviest elements sink, lightest elements rise to surface; the Earth is now layered.

Earth's Internal Structure

Earth layers based on composition and rheology

• core
• mantle
• crust
• layers based on physical properties
• inner core
• outer core
• mesosphere
• asthenosphere
• lithosphere

Internal Heat of the Earth

Why is the Earth hot?
Heat transfer mechanisms
Conduction
Convection
Radiation

Plate Tectonics

Types of plate boundaries:

• Transform
• Divergent
• Convergent (collision and subduction)

Plate tectonic theory
Alfred Wegner's original idea of "Continental Drift"
Harry Hess and evidence for "Sea Floor Spreading" (from both videos)
Continental Drift and Plate Tectonics (in library VT-1261)
Planet Earth Living Machine (in library VT-869)
Pacific NW local plate tectonic setting
What plate are we on?
What plate is subducting beneath us?
Hot spots
Seamounts
Volcanic islands
Guyots
Plate boundaries and location and types of earthquakes?
Plate boundaries and location and types of volcanoes?
Pacific NW local plate tectonic setting
What plate are we on?
What plate is subducting beneath us?
Hot spots
Seamounts
Volcanic islands
Guyots
Plate boundaries and location and types of earthquakes?
Plate boundaries and location and types of volcanoes?

Geologic Time

Put the eras and periods in the right order (p. 17)
The rock cycle
Magma/lava
Crystallization
Igneous Rocks
Weathering
Sediment
Lithification
Sedimentary Rocks
Metamorphism
Metamorphic Rocks
Melting

Minerals

Definitions

• Rocks
• Minerals
  
• Elements
  
• Atoms
  
• Compounds

Factors controlling a mineral's composition and structure
Relative abundance of elements
Know the 2 most abundant elements
Silicates (most rocks in the crust are silicates, Si + O)
Relative sizes and charges of these elements' atoms and ions
Temperature and pressure at the time of formation
Polymorphs
How do we identify minerals?

Rocks

How do geologists classify Igneous rocks?

• Igneous Textures
• aphanitic
• phaneritic
• porphyritic
• phenocrysts
• groundmass
• glassy

• Igneous Compositions
• felsic
• intermediate
• mafic
• ultramafic

Igneous Rock Names

	INTRUSIVE	EXTRUSIVE
Ultramafic	peridotite
Mafic	gabbro	basalt
Intermediate	diorite	andesite
Felsic	granite	rhyolite

Creation of magma

Heat, pressure and water
Partial melting
Bowen's reaction series
Know order of crystallizationÑwhat minerals in ultramafic rocks to which minerals in felsic rocks Discontinuous series and continuous series
Processes which change the composition of magma
Fractional Crystallization
Assimilation
Magma Mixing

Plate tectonics and igneous rocks

Rock composition

• Oceanic hot spots
• Oceanic divergent plate boundaries
• Continents (primarily subduction zones)
• Continents (primarily continental hot spots)

Intrusive Igneous Rocks

Dikes, sills, laccoliths, and batholiths
Factors controlling types of eruptions
Viscosity (dependent on temperature and composition/silica content) and Gas content

Extrusive Igneous Rocks

Types of eruptions

• effusive
• pyroclastic (explosive)

Volcanic Deposits

• Lava (features: lava tubes, vesicles, scoria, columnar jointing)
• Basalt (pahoehoe, a'a)
• Andesite (thicker, shorter flows)
• Rhyolite (rare - usually form domes)
• Pyroclastic material
• Volcanic blocks
• Tephra
• Dust
• ash
• Lapilli
• Bombs
• Pyroclastic flows/nuŽe ardentes
• Lahars
• Gases

Volcanic landforms

• Craters
• Calderas
• Domes

Effusive eruptions

• Shield volcanoes
• Fissure eruptions (e.g., flood basalts, lava plateaus)

Pyroclastic/Explosive eruptions

• Cinder cones
• Stratovolcanoes/Composite cones
• Ash-flow eruptions