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ESS 101: Introduction to Geological Sciences
On campus Terry Swanson is the award-winning instructor for ESS 101. his is the class
description from his website http://faculty.washington.edu/tswanson/ESS/101.shtml
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ESS 101 Class Description
What Students Can Expect to Learn from the Course
After taking this course students will never look at the Earth the same! Students will learn
about how the Earth evolved from primordial dust to form the compositionally zoned planet
upon which life now exists. Students will learn about the unifying concept of plate tectonics,
which will provide them with a framework to understand the why and where of earthquakes,
volcanoes, mountain belts, ocean basins and rock types in their surrounding world. Students
will become amateur geologists and drive their friends and families crazy with their newfound knowledge. Students will also learn about time and its importance to the geologic
record. Students will learn that geologists pay more for their dates than Hollywood's most
elite stars! This course will provide students with important information about geologic
hazards, which will perhaps one day save lives or personal property. If students love the
outdoors, this course will give them many opportunities to visit spectacular geologic sites
around Washington state through the ESS 101 optional weekend field trip program. The
entire class will be invited to attend a special IMAX viewing of a geologic film at the Seattle
Center.
General Method of Instruction
Although the lecture of portion of this course is taught in a large lecture hall, I try to engage
all my students in small group discussions and interactive teaching techniques. I provide
weekly tutorial sessions outside of the lecture hall where students can receive enrichment or
extra help with the course material. I believe that my enthusiasm for my subject matter is as
important as the subject matter itself in facilitating student learning. I try to create a learning
environment in my classroom that enables all students the opportunity to achieve success if
they are willing to put forth the effort. I have an open-door policy and an approachability that I
believe promotes advanced discussion and interactions between myself and my students. I
have also learned over the many years of teaching at the University of Washington that my
students should play an important role in determining the content of my classes.
Consequently, I will ask my students to provide me feedback at the beginning of the quarter
to help me determine what they deem is important to learn in this exciting field of geology.
Laboratory consist of hands-on exercises where students learn to apply their knowledge in a
cooperative group setting. Students will also be given the opportunity to form laboratory
discussion groups to enrich their understanding and discuss differences of opinion regarding
relevant geologic issues. During the summer quarter laboratory is conducted outside to enjoy
the warm summer days in the Pacific Northwest.
A series of 7 to 9 optional field trips provides students with the unique opportunity to
experientially learn about geology in nature's back yard. The optional field trip opportunities
that this class provides are unparalleled at this University. Students are given the opportunity
to visit such locations as: Mount St. Helens, Mount Rainier glaciers, the Olympic Mountains,
the North Cascades, San Juan Islands, Seattle-Bainbridge Fault, Whidbey Island, fossil beds
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of the Chuckanut Formation, Gingko Petrified Forest and the coulees of the Columbia
Plateau. A special optional assignment to your local cemetary will be available during the
quarter as well.
Recommended Preparation for Success in this Course
This course is intended for non-major students who have little math or physical science
background. No pre-requisites are necessary to take this class. Please come with an openmind and inquisitiveness about your natural world. The material discussed this course will
engage all students, regardless of their respective academic backgrounds.
General Nature of the Assignments
Lecture and laboratory assignments will be completed during class time. There will be
reading assignments associated with the lecture portion of the course. Laboratory
assignments will be completed in the laboratory manual. Students will also be given an
opportunity to debate an issue of geological significance. Extra credit field trip assignments
are completed during each respective field trip.
Basis on which Grades are Assigned
Grades are assigned based on the following criteria:
140 points for laboratory (8 laboratory exercises, participation). Lab exam questions will be
given on the midterm and final exams (10 points each).
130 points for the Midterm (45 multiple choice questions and 5 bonus questions).
130 points for the Final (45 multiple choice questions and 5 bonus questions).
400 points total
On this same webpage are links to his
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syllabus (however, see topics below)
a sample midterm and final exam
Lab #1 Geologic Techniques: Maps, Aerial Photographs and LIDAR Imagery
Some of his class powerpoints.
On the next few pages is an outline of what Terry teaches over the 10 weeks of class on
campus.
On a separate document I have outlined what we expect to be taught in ESS 101
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1. Evolution of the Earth and Plate Tectonics
I) Introduction
A) Course expectation
B) Syllabus
C) What is geology?
II) Evolution of the Earth
How does the Earth become compositionally zoned and differentiated?
1) Accretion of planetesimals
2) Initial heating
3) Radioactive heating
4) Iron Catastrophe
5) Differentiation (formation of atmosphere and oceans)
6) Convective overturn
Compositional Zonation is based on density differences between Earth Materials.
III) Internal Structure of the Earth
A) How are we able to determine the structure and composition of the Earth's interior?
1) Density
2) Magnetic field
3) Seismic properties
B) Major Structural Units (based on compositional properties)
1) Solid inner core
2) Liquid outer core
3) Mantle
4) Crust
C) Gravity
1) Gravity anomalies
2) Isostasy
IV) Additional Structural Units (based on physical properties)
A) Lithosphere
B) Aesthenosphere
V) Plate Tectonics - A Unifying Theory
Prior to the late 1960's there was no general theory to explain the whole range of geologic processes.
A) Mechanism of plate tectonics
1) Lithosphere-Aesthenosphere Dynamics
2) Divergent margin (sea-floor spreading zone)
3) Convergent margin (subduction and collision zones)
4) Transform margin (transform fault)
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B) Lithospheric plate margins
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Outline #2: Minerals
Chemistry Review
Compounds and Ions: Compounds, Energy-Level Shells, Ions, Molecules
Bonds: Noble Gases, Ionic Bonds, Covalent Bonds, Metallic Bonds
What is a mineral?: A mineral is a naturally occurring inorganic solid compound characterized by a specific
(atomic) internal structure and by a specific chemical composition. All minerals will possess certain diagnostic
physical properties.
Growth of minerals: Minerals grow by crystallization--atoms are arranged in a specific geometric pattern.
Minerals are precipitated from aqueous solutions by evaporation at atmospheric pressure and temperature, and
from a melt (magma) where crystallization occurs well above the boiling point of water.
Rate of Cooling and Crystal Size: The slower the rate of cooling the larger the individual crystal growth.
Physical Properties of Minerals: The more important physical properties of minerals are:
1) Crystal form
2) Cleavage
3) Hardness
4) Specific gravity (density)
5) Color
6) Streak
7) Luster
8) Optical properties
9) Reaction to HCl
10) Magnetism
11) Taste
Common rock forming minerals:
The Silicates:
quartz, muscovite, feldspar group, biotite, amphibole, pyroxene, olivine, clay minerals (alteration of aluminium
silicates).
Other Minerals:
oxides, sulfides, carbonates, phosphates, sulfates
Rock Cycle
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Outline #3: Igneous Rocks and Volcanism
I) Magma
Composition:
-Controlled by the most abundant elements in the upper mantle and crust.
-Magmas are divided into three compositional ranges based mainly on SiO2 content.
-Dissolved gases in magma
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Temperature:
Magma temperatures range between 1040° to 1200°C. Magma can form at lower temperatures if water is
dissolved in the melt.
Viscosity:
The internal property of a liquid that manifests resistance to flow. Viscosity of a magma depends on
temperature and composition (silica and dissolved gas content).
II) Formation of Magma
Geothermal gradient:
Pressure and melting:
-Dry vs. wet melts
-Magmatic differentiation by partial melting
*Important: The composition of a magma that develops by partial melting will depend on: 1) the composition
of the parent rock, and 2) the percentage of the rock that melts.
III) Magma types
Formation of basaltic magma:
Formation of granitic magma:
Formation of andesitic magma:
IV) Igneous Rocks
Solidifying magma
-Magmatic differentiation by fractional crystallization:
Bowen's reaction series:
-Continuous reaction series: coupled substitution of Ca+2 and Al+3 are replaced by Na+1 + Si+4 in the
feldspars.
-Discontinuous reaction series: early formed minerals form entirely new compounds through reactions with the
remaining liquid.
Classifying Igneous rocks
-Texture
-Composition
V) Volcanic Landforms
Shield volcanoes
Pyroclastic cones
Stratovolcanoes (composite)
-lava domes
Craters and Calderas
Thermal springs and geysers
Fissure eruptions on land
Fissure eruptions beneath the sea (Divergent margins)
VI) Plutons
Minor Plutons: dikes, sills, laccoliths, volcanic pipes and necks
Major Plutons: batholiths, stocks, stoping, xenoliths
VII) Volcanic Hazards
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Lava Flows
Tephra fallout
Nuee Ardentes
Volcanic Lahars
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Outline #4 Weathering
Weathering is the chemical alteration and physical breakdown of rock material during exposure to the air,
moisture, and organic matter.
Mechanical Weathering:
Forms of mechanical weathering:
-development of joints:
-joint sets.
-crystal growth
-frost wedging
-effects of heat
-bioturbation
Chemical Weathering
Common Chemical Weathering Reactions
-carbonation
-hydrolysis:
-oxidation:
-hydration/dehydration
-dissolution
Weathering Effects on Common Rocks
-Concentration of Stable Minerals:
-Weathering Rinds:
-Exfoliation and Spheroidal Weathering
Factors That Influence Weathering
-Rock type and structure
-differential weathering
-Slope
-Climate
-Time
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Outline #5 Sedimentary Rocks
Sediment to Sedimentary Rock
-accumulation
-compaction
-cementation
Classifying Sedimentary Rocks: sedimentary rocks are classified according to the size, shape, and composition
of their constituent particles.
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Clastic Sedimentary Rocks: accumulated particles of broken rock or skeletal remains of dead organisms.
-conglomerate, sandstone, siltstone, mudstone (shale)
-sedimentary breccia, coquina
Chemical Sedimentary Rocks: formed by precipitation of minerals from solution in water.
-limestone, dolostone, rock salt
Diagenesis: refers to changes that affect sediment after its initial deposition.
-compaction, cementation, recrystalization, oxidation, reduction
Sedimentary Structures (Features)
-stratification
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parallel strata
cross strata
-rounding
-sorting
-Arrangements of particles within a stratum
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uniform layers
graded bedding
-Surface Features on Sedimentary Rocks
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ripple marks
mud cracks
-Fossils
Sedimentary Facies and Depositional Environments
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Outline #6 Stratigraphy and Geologic Time
I) How old is the Earth?
A) Literal Biblical interpretation (1654 - Archbishop James Usher)
-Catastrophism
B) Principal of uniformitarianism (James Hutton, 1785)
-"the present is the key to the past"
-The laws of nature do not change with time.
-The Earth has evolved by uniform, gradual processes over an immense span of time.
-Sir Charles Lyell (1797-1875) Principles of Geology (process rates do not change)
-Charles Darwin (1809-1882) Origin of Species by Natural Selection
C) Early estimates of geologic time based on quantitative data:
1) salinity of the oceans
2) thickness of sediment
3) heat loss from the earth
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II) Relative Dating
-determining the chronologic order of a sequence of events
Relative dating is accomplished by applying the principles of stratigraphy
A) Principles of Stratigraphy
1) the principle of superposition (Nicolaus Steno, 1669)
-we must assume that:
i) rock layers were horizontal when they were deposited.
ii) the rocks have not been so severely deformed that the beds are overturned.
2) the principle of faunal succession
3) the principle of crosscutting relations
4) the principle of inclusions
C) Breaks in the Stratigraphic Record (Unconformities and hiatuses)
-An unconformity is a substantial break or gap in a stratigraphic sequence that marks the absence of part of the
rock record
-A hiatus is the lapse in time recorded by an unconformity
1) Angular unconformity
2) Disconformity
3) Nonconformity
III) The Geologic Time Scale
-using the principles of superposition and faunal succession, geologists have determined the chronologic
sequence of rocks throughout broad regions of the world and have constructed a standard geologic time scale.
-Rock units are distinguished from each other by major changes in rock type, unconformities, or abrupt vertical
changes in the fossil groups they contain.
-Divided into geologic time units which are used worldwide: eons, eras, periods, and epochs.
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I) Chemistry Review:
II) Radiometric Dating
A) Natural Radioactivity
-Some chemical elements composing the Earth are radioactive and therefore unstable.
-In radioactive elements, the unstable nucleus is spontaneously transformed to a more stable isotope of the same
chemical element or a stable nucleus of a different chemical element. (Radioactive decay).
-parent vs daughter product
Age Equation: D = D0 + N(eλt - 1) where: D = the number of daughter atoms in sample at the present, D 0 = the
original number of daughter atoms, N is the number of parent atoms at the present λ = the decay constant, t =
time
B) The Radioactive Decay Process
1) Simple decay
2) Branching Decay
3) Chain Decay
C) Rates of Decay
The rate of decay of the unstable parent radionuclide decreases exponentially (it is not linear).
The rate of decay is defined by half-lives (see Fig. 6.14 in text).
Different radionuclides have different half-lives and therefore different effective dating ranges.
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D) Dating geologic and biologic materials by radioactive elements:
When D and N have been measured and an appropriate value of D 0, the above equation can be solved for time
(t).
Assumptions of radiometric dating:
1) The rock or mineral must be a "closed system."
2) We must be able to accurately determine a value for the initial daughter atoms if they were present in mineral
or rock sample being dated.
3) The value of the decay constant (λ) must be known accurately.
4) The measurements of the parent and daughter atoms must be accurate and representative of the rock or
mineral to be dated.
Isotopic Dating Systems
1) Potassium-Argon (40K/40Ar) Dating T1/2 = 1.3 b.y.
2) Uranium-Lead Dating 238U T1/2 = 4.5 b.y. 235U T1/2 = 710 m.y.
3) Fission Track Dating
4) Radiocarbon (14C) Dating T1/2 = 5,730 years
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Outline #11 Metamorphism and Metamorphic Rocks
Metamorphism: refers to all changes in mineral assemblages and texture of rock that take place within the
Earth's crust, as a result of changes in temperature and pressure.
Factors Controlling Metamorphism:
1) Precursor mineral assemblages
2) Intergranular fluid: facilitates the chemical reactions that occur to minerals as they are subjected to
changing temperatures and pressures. When a "dry" rock is heated, few changes occur because the growth of
new minerals means that atoms must move by diffusing through solid materials (very slow process).
3) Grade of Metamorphism
-Low grade metamorphism: rock changed at low temperatures and low pressures. Contain many hydrous
minerals which are converted to anhydrous (no water) minerals with increasing temperatures and pressures.
High grade metamorphism.
Prograde vs retrograde metamorphism: P.G. temperature and pressure are rising. R.G. temperatures and
pressures are declining. Retrograde metamorphic effects are extremely slow compared to prograde. Why do you
think this is the case?
4) Temperature: When rocks are heated, new mineral will grow which are stable at higher tempertures.
Temperature and pressure must be considered together.
5) Pressure: Because the composition of the rocks being metamorphosed and the temperature-pressure
conditions within the crust vary widely, the mineral assemblages in metamorphic rocks also range widely.
By comparing mineral assemblages created under different pressure- temperature conditions in the lab, we can
determine the ranges of pressure-temperature conditions under which metamorphism occurs in the crust.
6) Time: coarse-grained metamorphic rocks are products of long-sustained metamorphic conditions.
Kinds of Metamorphism:
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1) Cataclysmic Metamorphism
2) Contact metamorphism -metamorphic aureole; hornfels
3) Burial Metamorphism -Zeolites
4) Regional Metamorphism
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Outline #8 Deformation of Rock and Geologic Structures
How is rock deformed?
Stress and strain
Elastic deformation
Deformation by brittle fracture
Ductile Deformation
Ductile Deformation versus Brittle Fracture
Controlling Factors
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temperature
confining pressure
time
strain rate
composition
Evidence of Deformation (Geologic Structures)
Brittle Fracture
Faulting
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Normal Faults
Reverse Faults
Thrust Faults
Strike-slip
Transform faults
Geologic Evidence of Movement along Faults
Joints
Ductile deformation (bending of rocks)
Measuring folded rock
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strike and dip
Classifying folds
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monoclines
anticlines
synclines
plunging folds
complex folds
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Outline #9 Seismology, Earthquakes, and Tectonic Hazards
Earthquakes
What are they?
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Elastic-rebound theory
Origin of Earthquakes
Seismic Waves
Body waves versus surface waves
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P-waves (compressional)
S-waves (shear)
surface waves
Location of the Epicenter
Magnitude of Earthquakes
Richter Magnitude scale
World Distribution of Earthquakes
Earthquakes and plate tectonics
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Seismicity at divergent plate boundaries
Seismicity at convergent plate boundaries
Intraplate seismicity
Tectonic Hazards and Earthquake Disasters
Earthquake occurrence and damage
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Modified Mercalli Scale
Prediction and Prevention
Earthquake Safety
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Outline #10 Earth's Magnetism and Plate Tectonics
Earth's Magnetic Field
The Earth has an invisible magnetic field that permeates everything.
The Earth's magnetism is believed to be controlled by fluid motions generated in the outer core.
Thermoremanent Magnetism
Iron-bearing minerals can become permanently magnetized.
Curie Point: all permanent magnetism is destroyed at a temperature above the mineral's Curie point (Curie point
for magnetite is 500°C).
The Polarity-Reversal Time Scale
Chrons: extended periods of either normal or reversed polarity.
Subchrons: short term magnetic reversals that can occur within a chron.
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Depositional Remanent Magnetism
Sedimentary rocks acquire a weak but permanent magnetism through the orientation of magnetic grains during
or after sedimentation.
Plate Tectonics: The Evidence
-Continental Drift
-Evidence for Pangea (the super continent)
-Apparent Polar Wandering
-Seafloor Spreading
Two lines of evidence of Seafloor Spreading
-Mantle hot spots
-Thermoremanent magnetism in the oceanic crust.
Causes of Plate Tectonics
Convection in the Mantle
1) Movement confined to the asthenosphere and lithosphere (no movement below 670 km).
2) Heat source orginates from the outer core and is transfered through the entire mantle.
3) Stacked convection system.
Movement of the Lithosphere
1) Pushing of the lithosphere
2) Dragging of the lithosphere
3) Sliding of lithosphere away from the spreading center.