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Geology 106
PHYSICAL AND HISTORICAL GEOLOGY
(Second semester, first year Geology)
Lecture Component
Publishing date
December 2009
Author
Gary Clohan, B.Sc., M.ED.
Institution
College of the Rockies
Project information
This curriculum comprises the lecture component of Geology 106, developed
for the Web-based Associate of Science Program Development Year 2 project
(WASc2). The project was funded by BCcampus.
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GEOLOGY 106: Physical and Historical Geology
Course Units
WEEK ONE: The Big Picture = Plate Tectonics ............................................................................... 3
WEEK TWO: Plate Tectonics and Earthquakes ............................................................................ 18
WEEK THREE: First the Sea Floor, then Deformation and Mountain Building ............................ 30
WEEK FOUR: Deformation and Mountain Building, Continued .................................................. 51
WEEK FIVE: Geologic Time ........................................................................................................... 56
WEEK SIX: Evolution ..................................................................................................................... 70
WEEK SEVEN: Catch-Up and Review!........................................................................................... 81
WEEK EIGHT: Midterm Exam Week ............................................................................................. 85
WEEK NINE: The Ancient History of the Earth ............................................................................. 86
WEEK TEN: Paleozoic Earth History ............................................................................................. 95
WEEK ELEVEN: Paleozoic Life History ........................................................................................ 105
WEEK TWELVE: The Mesozoic.................................................................................................... 115
WEEK THIRTEEN: The Cenozoic.................................................................................................. 123
WEEK FIFTEEN: This is the End! ................................................................................................. 138
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WEEK ONE: The Big Picture = Plate Tectonics
Welcome to Week 1 of your GEOL 106 course. Your main assignment for this week is to begin
the readings in your textbook and lab book. Since on average you are expected to read about
one chapter per week, you do not want to get behind at the beginning!
If you happen to have previously taken GEOL 105 or a similar course, then much of this first
week material should be review for you. If such is the case, you may be able to get away with
just skimming the first, introductory, chapter in your text, but that's not the case with Chapter
2. Even if you've read it before, you should read it again, and read it carefully. Plate Tectonics,
as the chapter title implies, is truly the "Unifying Theory" in Geology today. Many topics you
will cover this semester, for example some of the principles of relative age dating (concepts
such as the idea that older rock is usually found under younger rock), have been around a very
long time. However, the idea that this is all related and tied together (by what we now call the
theory of plate tectonics) is only a few decades old. Elegant yet in some ways simple, plate
tectonics allow us to explain the locations of many earthquakes, volcanoes, and tsunamis
around the world. Most pertinent to this course, the theory also allows us to explain the
sometimes-strange records in the rocks we find on our planet. Why do former ocean
sediments, for example, end up near the top of Mt. Everest? Well, plate tectonics gives us
many clues. Throughout this course, we will be spending time trying to put many of the pieces
of geologic puzzles together, such as looking at diagrams of folds and faults, locating
earthquakes, orienting geologic formations in three-dimensional space, and identifying fossils,
just to name a few things. The Big Picture which we always come back to, however, is plate
tectonics. It explains a lot!
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ASSIGNMENTS FOR WEEK ONE:
Textbook Reading: Chapters 1 and, especially, 2
Lab Book Reading: Whenever you are assigned exercises from your lab book, you should make
sure that you read all introductory material prior to the actual assigned exercises. If you simply
jump ahead to the specific exercise pages without reading the previous pages, you are likely to
end up spending more overall time in figuring out just what the exercises are asking you to do.
For future weeks, no specific Lab Book Reading will be assigned. Rather, it will be assumed that
you can easily determine which introductory pages apply to the weekly assigned exercises.
Notes: You may wish to consult the notes labeled "Introduction" and "Plate Tectonics" and add
to them as you see fit from your studying. You may also wish to examine web resources listed
on this site, in your textbook, in your lab book, on the companion sites, or mentioned by your
instructor.
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Lab Assignment: T here is no official lab assignment for week one other than the "Reading and
Preparation" Assignment described for the week. However, if you have the time and wish to
jump on top of things, you are free to begin the plate tectonic exercises described in week 2.
Other Assignment: Participate in the "Please Introduce Yourself" Discussion Forum.
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Introduction
SOME KEY INITIAL CONCEPTS IN GEOLOGY
Geologic Time Scale
o
Vast Times to Comprehend
Uniformitarianism Principle
o
Present day processes have operated throughout geologic time
o
“The Present is the key to the Past”
o
Processes don’t change, but RATES might
Plate Tectonics
Continental Drift (Wegener) + Sea-Floor Spreading = Plate Tectonics
Based on Evidence from:
o
Jigsaw Puzzle Fit of Continents
o
Geologic Similarities: Rocks
o
Geologic Similarities: Fossils
o
Geologic Similarities: Mtn. Ranges
o
Paleoclimatic Data
o
Pacific “Ring of Fire”
o
“Polar Wandering”
o
Magnetic Reversal Patterns
o
Age of Ocean-Floor Rock
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Plate Tectonics
Alfred Wegener, 1915
Theory of Continental Drift
Evidence =
o
“Fit” of continents as in a jigsaw puzzle
o
o
Esp. S. America & Africa
Structural Evidence
Similar Mtn. Ranges
Similar Rock Formations
Fossil Evidence
"Super Continents"
Union of:
o
Gondwana (S. Continents)
o
+ Laurasia (N. Continents)
= Pangaea
More Recent Data (1950s & later)
Paleomagnetic Study
o
Polar Wandering
o
Ocean Floor Magnetic Anomalies
= proof of Sea-Floor Spreading
Continental Drift + Sea-Floor Spreading = Plate Tectonics
Types of Plate Boundaries
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Convergent (i.e. subduction zone related)
o
Continental—Oceanic
o
Continental—Continental
o
E.g. the Andes
E.g. the Himalayas
Oceanic—Oceanic
E.g. Volcanic Island Arcs
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Divergent (i.e. spreading centers)
o
Mid-Ocean Ridges
o
Continental Rift Valleys
Incl. Iceland case
E.g. Africa
Transform
o
E.g. San Andreas Fault
Rates of Plate Motion
Cms /year
Relative plate motion measured by:
o
Dating Ocean Rocks
Oldest ~180m.y.
o
Dating Magnetic Reversal patterns
o
Satellite, Laser, GPS
Also plate movement over Hot Spots/Mantle Plumes
o
E.g. Hawaii case
o
Absolute plate motion
Supercontinent Cycle = Wilson Cycle ~ 500m.y.
Former Subduction Zone Clues
Andesite
Ophiolite Rock Sequence
o
Involves characteristic strata section = “ Ophiolite Suite”:
Sediments (on top)
Pillow Basalts (= ocean crust)
Gabbro
Peridotite (= mantle rock)
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Found in Appalachians, Alps, Andes, Himalayas
o
Newfoundland example at Gros Morne
Represents a section of ocean crust that was not subducted
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Convection Currents = “Driving Mechanism” for Plate Tectonics
Model 1: Thermal Convection Cells are limited to Asthenosphere
Model 2: Cells in entire Mantle
Transfer of heat from Core to Crust is involved
Gravity may play a role
o
“Slab-Pull”
o
Colder, denser, subducting lithosphere “pulls” plate along
“Ridge-Push”
Higher mid-ocean ridge “pushes” plate
Resources are associated with plate tectonic boundaries
E.g. hydrothermal deposits at spreading centers
o
Red Sea
o
Crete
Subduction -zone related
o
E.g. porphyry copper in Chile
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Learning Objectives for Week 1
Upon completion of this material, the student should understand the following.
Geology is the study of Earth.
Earth is a complex system of interconnected components that interact and affect one
another in various ways.
Theories are based on the scientific method and can be tested by observation or
experiment.
Geology plays an important role in human experience and affects us both as individuals
and members of society and nation-states.
The universe is thought to have originated approximately 14 billion years ago with a big
bang. The solar system and planets evolved from a turbulent, rotating cloud of material
surrounding the embryonic Sun.
Earth consists of three concentric layers—core, mantle, and crust—and this orderly
division formed during Earth’s early history.
Plate tectonics is the unifying theory of geology and this theory revolutionized the
science.
The rock cycle illustrates the interrelationships between Earth’s internal and external
processes and shows how and why the three major rock groups are related.
The theory of organic evolution provides the conceptual framework for understanding
the history of life.
An appreciation of geologic time and the principle of uniformitarianism is central to
understanding the evolution of Earth and its biota.
Geology is an integral part of our lives.
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Important Terms for Week 1
asthenosphere
Jovian planets
rock
Big Bang
lithosphere
rock cycle
core
mantle
scientific method
crust
metamorphic rock
sedimentary rock
fossil
mineral
solar nebula theory
geologic time scale
organic evolution
system
geology
plate
terrestrial planets
hypothesis
plate tectonic theory
theory
igneous rock
principle of uniformitarianism
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Web Resources for Week 1
These are some web resources that may be helpful for your studies during this week. You may
also want to consult the ongoing Forum related to web resources to see if additional websites
are recommended by other students or your instructor.
Introductory Chapter:
1. Introduction to the Nine Planets
http://www.seds.org/nineplanets/nineplanets/intro.html
2. Goddard Space Flight: Earth Observing System
http://eospso.gsfc.nasa.gov/
3. Smithsonian: This Dynamic Earth
http://www.mnh.si.edu/earth/
4. Visible Earth: NASA
http://visibleearth.nasa.gov/Solid_Earth/
5. Carbonfund.org
http://www.carbonfund.org
6. Greenhouse Gas Online
http:///www.ghgonline.org
Plate Tectonics Chapter:
1. The Plates Project
http://www.ig.utexas.edu/research/projects/plates/index.htm
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2. Smithsonian: This Dynamic Earth
http://www.mnh.si.edu/earth/
3. Plate Tectonics Animations
http://www.ucmp.berkeley.edu/geology/anim1.html
4. Plate Tectonics http://www.platetectonics.com/
5. Northern California Earthquake Data Center (NCEDC)
http://quake.geo.berkeley.edu/
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6. Gondwana Reconstruction and Dispersion
http://www.searchanddiscovery.net/documents/97019/index.htm
7. The Restless Earth, The Burke Museum of Natural History and Culture, University of
Washington
http://www.washington.edu/burkemuseum/geo_history_wa/The%20Restless%20Earth
%20v.2.0.htm
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DISCUSSION FORUM: Please Introduce Yourself!
Let's start off by getting to know each other.....
Please introduce yourself to others who are in the course, and perhaps include a little bit about
your background and interest in geology. This will be the start of our forums and will hopefully
get the ball rolling for our regular communication. We will be having a total of seven of them,
and hopefully it'll become a regular habit for you to participate (and yes, your participation will
also count for something grade-wise!).
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WEEK TWO: Plate Tectonics and Earthquakes
Well, hopefully by now your mind and spirit are getting in tune with looking at the world
geologically. Who knows, you may never be the same! As mentioned at the outset of Week 1,
Plate Tectonics is a very important topic in any study of geology. That's why Chapter 2 is
considered quite important for both GEOL 105 and GEOL 106. Plate tectonics is integral to
understanding all the landform processes discussed in 105, and it is also integral to the
structural and historical processes discussed in this course. Therefore, you may want to read it
over more than once before this term is over.
For now, we are embarking on a new topic, namely Earthquakes and the Earth's Interior, but
like any geologic topic, it can all be related back to the Big Picture of plate tectonics.
We all know something about earthquakes, certainly we hear about them on a fairly regular
basis and it's quite possible that a significant quake will happen during our semester.
Whenever people are affected, earthquakes represent a compelling natural hazard. Although
great efforts go into trying to understand the dynamics of quakes, we are a long way from being
able to accurately predict exactly when these fault movements will occur. If in the future one
of you comes up with a sure-fire method of prediction, there's probably a Nobel Prize in it for
you! At this point in our studies, however, we will try to understand some of the basics of the
subject.
ASSIGNMENTS FOR WEEK TWO
Textbook Reading: Chapter 8
Lab Book Reading: We will mention one more time that you should be reading the appropriate
pages in your lab book related to the assigned exercises.
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Notes: You may wish to consult the notes labelled "Earthquakes" and add to them as you see
fit from your studying. You may also wish to examine web resources listed on this site, in your
textbook, in your lab book, on the companion sites, or mentioned by the instructor.
Lab Assignment: Plate Tectonics and Quakes, Part 1
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Earthquakes
Earthquake = Sudden release of energy, usually along a fault, produces vibrations
Rocks deform by bending first, then breaking (= quake)
o
Elastic Rebound Theory
Seismograph records shaking and allows accurate location of:
o
o
Focus
Shallow (less than 70 km)
Intermediate (70-300 km)
Deep (greater than 300 km)
Epicenter = Surface Location
Quakes and Plate Margins
Transform & Divergent Boundaries
o
Converging Boundary
o
Shallow Focus
Intermediate to Deep Focus
Occur along Benioff Zone
~45 degrees of plunge
Esp. circum-Pacific belt
95% of Quakes are associated with plate margins, but:
o
New Madrid, Missouri, 1811
o
Charleston, S.C., 1886
Mohorovicic Discontinuity
Moho = Boundary between Crust and Mantle
20-90 km (avg. = 30) under Continents
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5-10 km under Ocean crust
Below moho p-waves travel faster
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Seismic Waves
Body Waves (travel through Earth)
o
o
P Waves (Primary)
Compressional
Travel through solid, liquid, gas
Arrive at seismography first: Fastest
S Waves (Secondary)
Shear waves
Movement perpendicular to wave travel
Only through solids
Arrive at seismography second
Surface Waves (cause damage)
o
R Waves
o
L Waves
Similar to water waves
Lateral motions, can cause severe shaking
P-Wave/S-Wave data have led to conclusions about the internal structure of earth
o
E.g. Crust, Mantle, Liquid Outer Core, Solid Inner Core
Velocity of seismic waves controlled by elasticity and density of rock types
Waves are refracted (bent) and reflected due to encountering different materials
Earthquake Damage Factors
Location of Epicenter
o
Depth of Focus
o
i.e. if close to people
Shallow is worst
Magnitude (= Richter Scale)
o
Quantitative measure of energy release
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o
Logarithmic scale based upon wave amplitude (e.g. Magnitude 3 quake = 30
times “stronger” than Magnitude 2 quake
o
Relates to P/S wave time difference in arrival at seismograph
Intensity (e.g. Mercalli Intensity Scale)
o
Qualitative, Damage-related
Type of Ground/Rock
Building Standards
Lack of Preparedness
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Liquefaction
Marine sediments (= deposited in salt water)
Relative sea-level drop, exposing sediment
Salt water replaced by fresh water, which weakens bonds
People build on it
Quake leads to liquefaction
o
“House of Cards”
o
E.g. Richmond, BC
o
E.g. Marina District in 1989 San Francisco “World Series” quake
Tsunami
Tsunami = Seismic Sea Wave, not “Tidal Wave”
Generated by Earthquake or Turbidity Flows/Slumps
May be unrecognizable in ocean
E.g. Port Alberni BC in 1964 due to Alaska quake
E.G. Big Asian Tsunami of 2004 (Indonesia, Thailand, etc.)
Earth "Precursors" & Prediction
Seismic Record
Seismic “Gaps,” i.e. recent quiet along a fault
o
E.g. San Andreas Fault is “locked” near San Francisco
Surface elevation and tilt
o
Similar to volcano forecasting
Groundwater fluctuations, e.g. well levels
Animals “6 th Sense”
Earthquake “Control:” Fluid Injection
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1989 Lomo Prieta Quake
= “World Series” quake
7.1 magnitude
18 km deep focus = deep for California
8 seconds shaking
Right lateral & oblique slip fault
Liquefaction in Marina District
Numerous aftershocks
Not “The Big One”
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1995 Kobe, Japan Quake
7.2 Richter Scale
60 seconds shaking
5000 dead, 300,000 homeless
Failure to:
o
Predict
o
Prepare
o
Mount Relief Effort
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Learning Objectives
Upon completion of this material, the student should understand the following.
Energy is stored in rocks and is released when they fracture, thus producing various
types of waves that travel outward in all directions from their source.
Most earthquakes take place in well-defined zones at transform, divergent, and
convergent plate boundaries.
An earthquake’s epicenter is found by analyzing earthquake waves at no fewer than
three seismic stations.
Intensity is a qualitative assessment of the damage done by an earthquake.
The Richter Magnitude Scale and Moment Magnitude Scale are used to express the
amount of energy released during an earthquake.
Great hazards are associated with earthquakes, such as ground-shaking, fire, tsunami,
and ground failure.
Efforts by scientists to make accurate, short-term earthquake predictions have thus far
met with only limited success.
Geologists use seismic waves to determine Earth’s internal structure.
Earth has a central core overlain by a thick mantle and a thin outer layer of crust.
Earth possesses considerable internal heat that continuously escapes at the surface.
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Important Terms for Week 2:
discontinuity
magnitude
refraction
earthquake
Modified Mercalli Intensity Scale
Richter Magnitude Scale
elastic rebound theory
Mohorovicic discontinuity (Moho)
seismograph
epicenter
P-wave
seismology
focus
P-wave shadow zone
S-wave
geothermal gradient
Rayleigh wave (R-wave)
S-wave shadow zone
intensity
reflection
tsunami
Love wave (L-wave)
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Web Resources for Week 2
These are some web resources that may be helpful for your studies during this week. You may
also want to consult the ongoing Forum related to web resources to see if additional websites
are recommended by other students or your instructor.
1. National Earthquake Information Center Home Page
http://wwwneic.cr.usgs.gov/
2. USGS Earthquake Hazards Program
http://earthquake.usgs.gov/
3. The Pacific Northwest Seismograph Network: Earthquake Prediction
http://www.geophys.washington.edu/SEIS/PNSN/INFO_GENERAL/eq_prediction.html
4. Northern California Earthquake Data Center (NCEDC)
http://quake.geo.berkeley.edu/.
5. Understanding Seismic Tomography
http://www.see.leeds.ac.uk/structure/dynamicearth/flash_gallery/layered_earth/seismi
c_tomography.html
6. Bay Area Regional Deformation Network
http://www.ncedc.org/bard/
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WEEK THREE: First the Sea Floor, then Deformation and
Mountain Building
The Sea Floor
We start this week by looking under the oceans at the floor of the sea. There are many neat
formations to be found out there, including the flat-topped mountains known as guyots. If you
are a fan of the book or movie version of "The Perfect Storm" then it may interest you to know
that the fishermen caught their fish around one of these guyots out in the middle of the
Atlantic. Speaking of fishing, the fact that, geologically-speaking, the continental shelf off the
coast of Newfoundland is much bigger than in most places has meant for some strange political
happenings in Canada. You see, it's so big there that it, along with the historically rich fishing
associated with it, extends into international waters. This means that other nations have spent
a lot of time fishing there too, and this has caused Canada lots of grief. The sea floor has also
provided geologists with some of the most compelling evidence for plate tectonics, evidence in
the forms of mid-ocean ridges and deep sea trenches. Unless you score a neat job or have your
own submarine, you may never get to see these things in person, but we can still learn about
them. In your text, this chapter is rather brief and quite readable. The lab material associated
with this topic is found in the exercises on plate tectonics.
Deformation and Mountain Building
Earthquakes happen when there is movement along geologic features known as faults (and yes,
many a lame joke is possible comparing human "faults" and geologic "faults"). Lots of fault
movement over lots of time (which is something we've had plenty of, at least geologicallyspeaking) leads to big things happening, including the creation of mighty mountain ranges. In
the textbook, this is an important chapter which probably needs to be read more than once.
Many of the concepts introduced in this chapter relate to specific skills you need to
demonstrate in your lab exercises. In particular, this is the week when we start working with
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strikes and dips. In theory, strikes and dips are pretty simple and straight-forward, but from
experience we instructors know that many students can get frustrated with the ins and outs of
actually using these concepts in the field or on lab problems. Many types of structures, such as
folds and faults, are also examined in some detail starting this week. In fact, this material is so
essential to the real and practical world of geology, we are allowing two weeks of class time to
let it sink in, not to mention several lab assignments. If you like working with puzzles, then you
should really enjoy the next few weeks of class!
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ASSIGNMENTS FOR WEEK THREE
Textbook Reading: Chapter 9, Chapter 10
Notes: You may wish to consult the notes labelled "Oceans" and "Deformation and Mountain
Building" and add to them as you see fit from your studying. You may also wish to examine
web resources listed on this site, in your textbook, in your lab book, on the companion sites, or
mentioned by the instructor.
Lab Assignment: Plate Tectonics & Quakes, Part Two
Other Assignment: Begin participation in the "Website Analysis" Discussion Forum, a forum
which will be on-going throughout the semester.
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Oceans
Oceans/Sea Floor
Until about 30 years, more was known about the moon that the oceans and sea floor
Studies based on:
o
Drilling
o
Seismic profiling
o
Gravity & Magnetic surveys
o
Echo sounding
o
“Going There”
Continental Margins
Separate the continents from the ocean basins
3 Parts
o
o
Continental Shelf
Part of continental plate
Gently sloping, shallow
Extends from 10s to 100s of km offshore
Continental Slope
Avg. depth 135m
Steeper than shelf
o
Continental Rise
o
Primarily Submarine Fans caused by Turbidity Currents
Passive vs Active (ie Subduction Zone) Margin
Abyssal Plains
Deep Sea Deposits
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Pelagic Sediments
o
Fell down from suspended matter
o
Includes Clays
o
Includes Oozes (shells of organisms)
Calcareous
Siliceous
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Other ocean basin features
Ocean Ridges
o
E.g. Mid-Atlantic Ridge
o
Rate of Spreading affects sea level
Seamounts
o
More spreading → More Magma Upwelling → Higher Sea Level
Underwater volcano
Guyots
o
Former volcano that reached ocean surface at one point
o
Flat-topped
Seamounts & Guyots may both be assoc. with Hot Spots/Mantle Plumes
Reefs
Primarily corals
Require clean, warm (20+C) water
Good indicators of environmental health
3 types of Reefs
o
Fringing: Attached to mainland
o
Barrier: Some ways offshore
o
Atoll: Roughly circular chain of islands
Ocean/Sea Floor Resources
Lots of international law and issues
Fish
o
“200-mile Limit”
o
E.g. Newfoundland “Nose & Tail”
Oil & Gas
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o
E.g. Hibernia (Newfoundland)
o
E.g. British Columbia?
o
E.g. Alaska/Canada North Slope
Manganese Nodules
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Deformation & Mountain Building
Major Mtn. systems are due to Convergent plate boundaries and Compression
Orogeny = Mtn. Building episode
o
E.g. Laramide Orogeny ( → Rocky Mountains)
o
Includes large-scale deformation, with:
Metamorphism
Batholiths
Volcanics
Orogenesis = Mtn. Building
Orogen = Segment w/in mtn. belts
In worlds mtn. systems, deformation increases from continental interior towards mtn.
chains
Current Orogensis found mostly in:
o
Alpine-Himalayan Belt
o
Circum-Pacific Belt
Mostly convergent zone related
o
Oceanic—Oceanic
Volcanic Island Arcs
Oceanic—Continental
o
Volcanic Mtn. Chain
E.g. the Andes
West Coast of S. Am. “switched” from passive to active ~200m.y.
o
Accretionary Wedge
o
Metamorphic Belts
Continental—Continental
o
E.g. Himalayas
India has been underthrust beneath Asia ~2000km\
At one point in the past, the scenario was similar to the Andes today
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Remember:
Continental Crust
o
o
Granitic
Lower density
More silica
Avg. 35km thick
20 in rift zones
90 in Himalayas
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o
o
Oceanic Crust
Basaltic
5 to 10 km thick
“Ophiolite Suite”
Isostacy & Isostatic Rebound
Strike & Dip
Used to describe orientation of planar geologic features
o
E.g. Bedding, Joints, Faults, Limbs of Folds
Strike = Compass Direction of a line of intersection between a horizontal plane and the
geologic planar surface in question
o
E.g. N10E, N45E, N50W
Dip = Angle between a horizontal plane and the geologic plane in question
o
Always between 0 (horizontal) and 90 (vertical)
o
E.g. 50SE, 10NW, 80SW
Special Cases
o
Vertical
o
Horizontal
Forces Acting on Rocks
Stress = due to force applied to rock
o
Compressional
o
Tensional
o
Shear
Strain = deformation due to stress
o
Elastic (= will rebound)
o
Non-Elastic
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Plastic Deformation (e.g. folds)
Fracture (e.g. faults)
All depends on:
o
Rock type
o
Temp.
o
Pressure
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Folding: Due to deep deformation
Basic Fold Types:
o
Monocline
o
Anticline (upfold)
o
Syncline (downfold)
Symmetry of Folds:
o
Symmetrical
o
Asymmetrical
o
Overturned
o
Recumbant (Axial Plane = Horiz)
Plunging vs Non-Plunging Folds
"Circular" Structures
Domes
o
E.g. Black Hills of S. Dakota
o
Perhaps due to mantle plume hot spot with no surface lava
Basins
Joints
Stress Fractures
Little or no movement
o
E.g. Anticline “Stretching”
o
Perhaps widening
Can lead to Arches, as in Arches National Park, Utah
Columnar Basalt
o
Columnar Jointing
o
Cooling Joints
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o
E.g. Devils Tower
o
E.g. Columbia Basalt Plateau
Sheeting Joints due to unloading
Faults
Fault Plane
Hanging Wall
Footwall
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Dip Slip Faults
o
Normal (Tensional)
o
Reverse ( Compressional )
o
Thrust (= low angle reverse, <45°)
~” Overthrust Fault”
E.g. Lewis Overthrust
Can cause “ Klippe ”
E.g. Crowsnest Mtn.(Alberta), Chief Mtn.(Montana)
Strike-Slip Faults (e.g. San Andreas)
o
Left Handed
o
Right Handed
Oblique Slip Faults
o
Combination of Dip Slip and Strike Slip
Mountain "Lingo"
Mountain “Systems”
o
Rocky Mountains
o
Appalachian Mountains
Mountain “Range”
o
Blue Ridge Mountains → Appalachian Mountains
o
Fisher Peak → Hughes Range → Kootenay Mountains → S. Cdn . Rockies →
Rocky Mountains
In addition to Converging/Subduction & Folding/Thrust Faulting, Mountains can also develop
by:
1. Hot Spot volcano or chain of islands
o
Hawaii
o
Galapagos
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2. Batholith Intrusion, Uplift, Erosion
o
Sierra Nevada Range in Calif.
3. Doming
o
Black Hills of South Dakota
o
May include Hogbacks (Flatirons) & Cuesta
Mt Rundle in Banff is an excellent Cuesta (but not due to doming)
4. Block Faulting
o
Normal Faults
Can produce
Horsts
Grabens
E.g. Basin & Range zone in Nevada
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o
Due to Tensional Forces
o
“Continental Stretching”
o
Rocky Mountain Trench = “Half Graben ”
Accreted Terranes
Microplates ”
o
Volcanic Arcs
o
Seamounts
o
Mid-Ocean Ridges
o
“Mini” Continents
Especially noted (& studied) in N. Am. Pacific Coast
Structural "Traps"
Remember Structural Traps (as in for oil & gas)
Can be due to:
o
Anticlines
o
Faulting
o
Salt Domes
45
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Learning Objectives for Week 3
Upon completion of this material, the student should understand the following.
For Oceans & Sea Floor Topics:
Scientists use echo sounding, seismic profiling, sampling, and observations from
submersibles to study the largely hidden seafloor.
Oceanic crust is thinner and compositionally less complex than continental crust.
The margins of continents consist of a continental shelf and slope and in some cases, a
continental rise with adjacent abyssal plains. The elements that make up a continental
margin depend on the geologic activity that takes place in these marginal areas.
Although the seafloor is flat and featureless in some places, it also has ridges, trenches,
seamounts, and other features.
Geologic activities at or near divergent and convergent plate boundaries account for
distinctive seafloor features such as submarine volcanoes and deep-sea trenches.
Most seafloor sediment comes from the weathering and erosion of continents and
oceanic islands and from the shells of tiny marine organisms.
Organisms in warm, shallow seas build wave-resistant structures known as reefs.
For Deformation & Mountain Building Topics:
Rock deformation involves changes in the shape or volume or both of rocks in response
to applied forces.
Geologists use several criteria to differentiate among geologic structures such as folds,
joints, and faults.
Correctly interpreting geologic structures is important in human endeavors such as
constructing highways and dams, choosing sites for power plants, and finding and
extracting some resources.
46
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Deformation and the origin of geologic structures are important in the origin and
evolution of mountains.
Most of Earth's large mountain systems formed, and in some cases, continue to form, at
or near the three types of convergent plate boundaries.
Terranes have special significance in mountain building.
Earth's continental crust, and especially mountains, stands higher than adjacent crust
because of its composition and thickness.
47
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Important Terms for Week 3
For Ocean/Sea Floor Topics:
abyssal plain
Exclusive Economic Zone (EEZ)
reef
active continental margin
guyot
seamount
aseismic ridge
oceanic ridge
seismic profiling
black smoker
oceanic trench
submarine canyon
continental margin
ooze
submarine fan
continental rise
ophiolite
submarine hydrothermal vent
continental shelf
passive continental margin
turbidity current
continental slope
pelagic clay
For Deformation & Mountain Building Topics:
anticline
footwall block
principle of isostasy
basin
fracture
reverse fault
compression
geologic structure
shear stress
continental accretion
gravity anomaly
strain
deformation
hanging wall block
stress
dip
isostatic rebound
strike
dip-slip fault
joint
strike-slip fault
dome
monocline
syncline
elastic strain
normal fault
tension
fault
oblique-slip fault
terrane
fault plane
orogeny
thrust fault
fold
plastic strain
48
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Web Resources for Week 3
These are some web resources that may be helpful for your studies during this week. You may
also want to consult the ongoing Forum related to web resources to see if additional websites
are recommended by other students or your instructor.
Oceans/Sea Floor Material:
1. NOAA Vents Program
http://www.pmel.noaa.gov/vents/
2. NOAA Oceans Home Page
http://www.noaa.gov/ocean.html
3. NOVA: Into the Abyss
http://www.pbs.org/wgbh/nova/abyss/
4. Oceanus: The Magazine that Explores the Oceans in Depth
http://www.whoi.edu/oceanus/index.do
Deformation & Mountain Building Material:
1. Himalayas : Where the Earth Meets Sky
library.thinkquest.org/10131/
2. USGS: Rocky Mountain System
http://wrgis.wr.usgs.gov/docs/usgsnps/province/rockymtn.html
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DISCUSSION FORUM: Website Analysis Forum
The idea behind this forum is to allow students in the class to compare notes concerning their
experiences with various websites. As pointed out every week, there are many resources
available on the web relating to almost any topic and geology topics are no exception. As
you've probably found out before, many websites just do not seem that useful. This forum is
the chance for you to give your opinion of what sites are good and helpful and which are not. If
there is general agreement about certain sites as being good or bad, then future students in
this course can benefit, since then your instructor can highlight those sites which have proved
to be most beneficial in the past. Your participation in the forum does not have to be a lengthy
examination of any site in particular. Even a brief opinion would be useful. At any rate, good
luck with your web-browsing.
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WEEK FOUR: Deformation and Mountain Building, Continued
Well, we said this was an important set of topics and that we'd spend the better part of two
weeks on it. So, here we are in the second week. Once again the Big Picture has to do with
Plate Tectonics, only this time we are concentrating a bit on the formation of continents. Who
would've thought, for example, that continents could "float" similar to the way icebergs float?
Or, who would've thought that Australia and India are actually joined together by one large
tectonic plate and that the whole thing has been slamming into Asia and creating the
Himalayas? Or, who would've thought that the Pacific Northwest of both the U.S. and Canada
is composed of "exotic" chunks of earth known as Accreted Terranes and that these things have
been "glued" onto the continent piece-by-piece?
The not-so-big-but-still-really-important pictures in this chapter have to do with some of the
basics of structural geology. This means not just faults, but also folds, domes, and other
structures. Although we may be moving on to new topics next week in terms of reading and
studying, the material in this chapter will be important for several more labs, not to mention on
exams!
ASSIGNMENTS FOR WEEK FOUR
Textbook Reading: Chapter 10
Notes: You may wish to consult the notes labeled "Deformation and Mountain Building" and
add to them as you see fit from your studying. You may also wish to examine web resources
listed on this site, in your textbook, in your lab book, on the companion sites, or mentioned by
the instructor.
Lab Assignment: Plate Tectonics and Quakes, Part 3
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Other Assignment: Participate in the "How About the Online Earthquake Exercise" Discussion
Forum.
52
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Learning Objectives for Week 4
Upon completion of this material, the student should understand the following.
Rock deformation involves changes in the shape or volume or both of rocks in response
to applied forces.
Geologists use several criteria to differentiate among geologic structures such as folds,
joints, and faults.
Correctly interpreting geologic structures is important in human endeavors such as
constructing highways and dams, choosing sites for power plants, and finding and
extracting some resources.
Deformation and the origin of geologic structures are important in the origin and
evolution of mountains.
Most of Earth's large mountain systems formed, and in some cases, continue to form, at
or near the three types of convergent plate boundaries.
Terranes have special significance in mountain building.
Earth's continental crust, and especially mountains, stands higher than adjacent crust
because of its composition and thickness.
53
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under the Creative Commons licence
Important Terms for Week 4
anticline
footwall block
principle of isostasy
basin
fracture
reverse fault
compression
geologic structure
shear stress
continental accretion
gravity anomaly
strain
deformation
hanging wall block
stress
dip
isostatic rebound
strike
dip-slip fault
joint
strike-slip fault
dome
monocline
syncline
elastic strain
normal fault
tension
fault
oblique-slip fault
terrane
fault plane
orogeny
thrust fault
fold
plastic strain
54
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Web Resources for Week 4
These are some web resources that may be helpful for your studies during this week. You may
also want to consult the ongoing Forum related to web resources to see if additional websites
are recommended by other students or your instructor.
1. Himalayas : Where the Earth Meets Sky
library.thinkquest.org/10131/
2. USGS: Rocky Mountain System
http://wrgis.wr.usgs.gov/docs/usgsnps/province/rockymtn.html
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WEEK FIVE: Geologic Time
If there's one thing geology has lots of, it's time. Specifically, in this case we are talking about
the concepts of Geologic Time and all that it implies. When we talk geology, it's easy to talk
about thousands, millions, even billions of years. The problem is that it's hard for us to truly
appreciate just how long these time periods are. Spreading rates of a few centimeters per year
along a mid-ocean ridge may not seem like much until you consider that it might be happening
for millions of years, in which case we have enough time for a large ocean to be created. One
has to always try to keep the time perspective in mind when thinking about various geologic
processes.
Time is of course also used to distinguish certain events as being older or younger than other
events. One way to do this is by using the Principles of Relative Age Dating, which are timetested (pun intended) methods of determining "which came first." This may be as simple as
supposing that the youngest stuff is on top and the oldest is on the bottom, but of course it's
often not as simple as that. These principles, along with an understanding of geologic contacts
known as unconformities, go a long ways in helping you solve the "puzzles" that are found in
the rocks. As mentioned last week, a good portion of your lab work during these weeks has to
do with solving such puzzles.
Another way to date rocks is to use techniques which usually involve radioactive decay. This
gives us an exact, or "absolute," age for rocks. For example, you may have heard that
researchers at McGill University recently claimed to have dated rocks which now would hold
the title as being "the oldest rocks in the world!" Fortunately for Canadians, these rocks, just
like the ones that used to be considered the oldest in the world, are found here in Canada.
That doesn't mean that Australians and the Africans aren't still hoping to take the title away
from us someday! At any rate, this is a good topic for study, even if we do not have the
sophisticated lab equipment at your disposal to actually date some rocks yourselves.
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ASSIGNMENTS FOR WEEK FIVE
Textbook Reading: Chapter 17
Lab Book Reading: As usual, you are expected you read the appropriate pages in your regular
lab book. However, this week you also need to refer to a special set of notes labelled
"Structural Geology Notebook." As explained there, those notes include not only quite a few
tips on how to deal with structural and historical geologic problems, they also include 17
Supplementary Lab Exercises that you need to work on over the next several weeks. In addition
to reading through the notes, you will need to print out specific pages because you need those
pages in order to complete the lab exercise. Speaking of printing things out, you may choose to
print out the entire Structural Geology Notebook for your reference.
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Notes: You may wish to consult the notes labeled "Geologic Time" and also "Absolute Age
Dating" and add to them as you see fit from your studying. You may also wish to examine web
resources listed on this site, in your textbook, in your lab book, on the companion sites, or
mentioned by the instructor.
Lab Assignment: Structural & Historical Geology, Part 1
Other Assignment: Participate in "Mnemonic Device" Discussion Forum.
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Geologic Time
“Lots of Time”
o
Eons, Eras, Periods, Epochs
o
A “mnemonic device” is handy
Age of Earth? ("expert" estimates of the day)
o
Pre-1700
o
o
<6000 years (Western thought)
1700+
Earliest science estimates (all low) based upon:
Erosion
Deposition
Ocean Salt Content
Kelvin (1866) estimate 20m.y.—100m.y.
Key people in early geology
Hutton (1726-1797)
o
“The present is the key to the past”
o
Uniformitarianism
Lyell (1830): “Principles of Geology”
Darwin (1859): “The Origin of Species”
Uniformitarianism
o
Same processes
o
Different Rates
vs.
Catastrophism
o
Huge events, e.g. hurricanes & floods
Tempest in a teapot??
Reign of “ Nonuniformitarian Uniformitarianism ”
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Principles of Historical Geology
“Fundamental Assumptions”
No unexplained instance of phenomena violating the assumptions has ever been
documented
Therefore, Principles ~ Laws
Principle apply mainly to Relative Geologic Time (i.e. which event is older) as opposed to
Absolute Geologic Time
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Principles
1. Uniformitarianism
2. Superposition
o
Youngest on top
o
Oldest on bottom
3. Original Horizontality
o
Beds laid down horizontally
4. Cross-Cutting
o
Younger “things” cut through or across older “things”
5. Lateral Continuity – Beds continue in all directions until . . .
6. Inclusions
o
If a rock is “trapped” inside other rock, then the trapped rock is older
7. Fossil Succession
o
Orderly age sequence to fossils
Oldest on bottom, youngest on top
Unconformity
“Discontinuity Surface” involving significant time
Initial deposition → Uplift, erosion, & perhaps deformation → New deposition
3 types of Unconformity
o
Disconformity
o
Angular Unconformity
o
Parallel sedimentary beds, often hard to tell
Non-parallel beds, usually easy to tell
Nonconformity
Igneous or Metamorphic Rock in contact with sedimentary
But we still need a time gap (= Hiatus )
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Remember, geologic surfaces of contact
Faults
Unconformities
Bedding Planes
Igneous Contact
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Stratigraphy: Terms
Correlation
o
Relates similar rock units in different areas
Thus establishing a regional time column
How? Principle of Lateral Continuity
Key Beds
o
Very distinctive rock units
o
E.g. Mt. Mazama ash (6600ybp)
Guide Fossils
o
Assemblage Range Zone: Possible time zone for any given fossil
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Absolute Age Dating
1903 Curie discovery of radioactivity
o
Source of heat for earth’s interior
o
“Serendipity”
Atoms
o
Protons (= Atomic Number)
o
Neutrons (+protons = Atomic Mass Number)
o
Electrons
Isotope = Different number of neutrons
Radioactive Decay: Spontaneous transformation from one element/isotope to another
Key Concept = Half Life
o
Time for ½ of Parent Element atoms to decay to Daughter Element atoms
o
Half-Life is Constant, whether it’s seconds or billions of years
o
Measurement of parent/daughter ratio is lab work: Mass Spectrometer
Common Isotope Pairs
U238 → Pb206
U235 → Pb207
Th232 → Pb208
Rb87 → St87
K40 → Ar40
Problems with Absolute Age Dating
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Best only for “undisturbed” igneous rock
Need “closed” system = no leakage of parent or daughter elements
Date = time of crystallization of mineral w/radioactive atom
Best if two decay sources available in one rock
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Other Dating Techniques
Fission Track Dating
o
When uranium has alpha decay, the mineral is damaged, leaving a “fission track”
o
40,000 to 1 million years, i.e. best for young samples
Carbon Dating
o
C14 Half-Life of 5700 years
o
Good for once-living but geologically young samples, less than 70,000 years
Dendrochronology
o
Very recent events (less than 14,000 years) can be correlated with tree ring
dates
Stratigraphy
Biostratigraphic Units
o
Based on fossil content
o
Biozone ~ Fossil Assemblage Zone
Time Units
o
Based on Geologic Time Scale
(e.g. Cambria = Ancient name of Wales)
o
Period Epoch Age
o
System Series Stage
Content: Lithostratigraphic Units = Most Common units
o
Bed or Member (e.g. Lower Middle Aldridge)
o
Of Formation (e.g. Aldridge Formation)
o
Of Group or Supergroup (e.g. Purcell Supergroup )
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Learning Objectives for Week 5
Upon completion of this material, the student should understand the following
The concept of geologic time and its measurements have changed throughout human
history.
The principle of uniformitarianism is fundamental to geology.
Relative dating—placing geologic events in a sequential order—provides a means to
interpret geologic history.
The three types of unconformities—disconformities, angular unconformities, and
nonconformities—are erosional surfaces separating younger from older rocks and
represent significant intervals of geologic time for which we have no record at a
particular location.
Time equivalency of rock units can be demonstrated by various correlation techniques.
Absolute dating methods are used to date geologic events in terms of years before
present.
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Important Terms for Week 5
absolute dating
principle of fossil succession
angular unconformity
principle of inclusions
biostratigraphic unit
principle of lateral continuity
carbon-14 dating technique
principle of original horizontality
correlation
principle of superposition
disconformity
radioactive decay
fission track dating
relative dating
guide fossil
time-stratigraphic unit
half-life
time unit
lithostratigraphic unit
tree-ring dating
nonconformity
unconformity
principle of cross-cutting relationships
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Web Resources for Week 5
These are some web resources that may be helpful for your studies during this week. You may
also want to consult the ongoing Forum related to web resources to see if additional websites
are recommended by other students or your instructor.
1. Dating Techniques
http://www.mnsu.edu/emuseum/archaeology/dating/index.shtml
2. University of California , Museum of Paleontology
http://www.ucmp.berkeley.edu/exhibit/geology.html
3. University of California , The Geological Time Scale
http://www.ucmp.berkeley.edu/exhibit/histgeoscale.html
Supplementary Materials for GEOL 106
You may see references to the Supplementary Lab Exercises, part of the “Structural
Geology Notebook” used for Weeks 5 through 9. These activities can be found in the GEOL
106 lab curriculum document for this project, on pages 48 to 75.
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WEEK SIX: Evolution
If you are a movie buff, perhaps you remember one called "Master and Commander," with
Russell Crowe in the lead as a fictional British sea captain in the early 1800s who roams the
world, often in pursuit of some French adversary. One of the spicy sub-plots was about a
member of his crew who had a special interest in all things natural, especially biologic things.
According to this sub-plot, when they happened upon the Galapagos Islands, this also-fictional
crew member started to discover all sorts of neat things, such as iguanas that swim and birds
with interesting adaptations. While collecting specimens on one of the islands, he notices the
enemy ship in another cove and is literally forced to drop everything in order to warn his
captain. Poor guy, they then have to go off to battle and he never gets a chance to further his
investigations.
If you know your history, the implication of the movie is clearly that this guy could've made
himself famous by discovering things that were later to make a fellow named Charles Darwin a
household name.
Darwin's genius lay in not just being a painstaking collector of evidence but in also being able to
theorize about what the evidence showed. We all know now that what it showed was some
startling examples of what we now call Evolution. The very idea was extremely controvsersial
then and to some folks it is still controversial today. We'll worry about trying to understand
some of the science behind it all. If you've taken biology courses in the past, there's a good
chance you've dealt with some of this material before. We also introduce fossils at this point,
even though you won't be dealing with them in lab exercises until a few weeks from now.
ASSIGNMENTS FOR WEEK SIX
Textbook Reading: Chapter 18
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Notes: You may wish to consult the notes labeled "Evolution and Fossils" and add to them as
you see fit from your studying. You may also wish to examine web resources listed on this site,
in your textbook, in your lab book, on the companion sites, or mentioned by the instructor.
Lab Assignment: Structural & Historical Geology, Part 2
Other Assignment: Participate in "Should We Debate Evolution" Discussion Forum.
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Evolution & Fossils
Theory of Organic Evolution
o
In Science, a Theory = hypothesis which has withstood repeated testing
Closer to “fact” than “theory” in everyday language
Up to ~1800, little thought given to the idea of slow evolutionary change over geologic
time
o
1830 = Lyell’s Principles of Geology
o
Darwin’s Grandfather = “The First?”
Lamarck vs. Darwin
Lamarck: “Theory” of Inheritance of Acquired Characteristics
o
Animals acquire traits during their life and pass on these traits to their offspring
Darwin = Theory of Natural Selection
o
1831-1836 = Voyage of the Beagle
o
1859 = The Origin of Species
o
He was influenced by Malthus (1766-1834)
Published with Wallace
Animals with favourable heritable variations are more likely to survive and pass
on these traits to their offspring
“Classic” Giraffe case
Darwin, the Scientist, Observed:
Artificial Selection of breeders
Fossils
Living species in different locales
o
E.g. Galapagos Islands
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The next step, Genetics
The How of variation required the work of Gregor Mendel (1860s), the father of
Genetics
o
The “Classic” Pea Experiments
Traits controlled by pairs of Genes
o
Dominant Allele, eg : R
o
Recessive Allele, eg : r
o
One from each pair from each parent
o
Variation is maintained
However, to explain evolution, we also need the concept of Mutations
Chromosomes (DNA molecules) carry genes, but genes can mutate and if the mutation
is favourable, in may induce a change, over time, in the population
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Species: Can mate and produce fertile offspring
If gene pool of population changes, then new species may evolve
Species may evolve via Allopatric Speciation
o
Small group of population is isolated due to a barrier
How Fast?
Gradual: Phyletic Gradualism
( vs ) In Spurts: Punctuated Equilibrium
Species Extinction
Pseudo = evolution into another species
( vs ) Real = gone forever
Often large gaps of time before “Reoccupation of the Niche”
Sometimes, Mass Extinctions
o
End of Paleozoic (245m.y.)
o
End of Mesozoic (66m.y.)
o
Right now?
“Variations on the Theme”
Divergent Evolution & Adaptive Radiation
o
Similar ancestral population turns into a variety of species due to adaptation to
environment
o
Adaptive radiation
o
E.g. Humans evolved from . . .
o
E.g. placental mammals
Convergent Evolution
o
Different ancestral populations develop similar adaptations
o
E.g. Aussie Marsupials look like N. Am. Mammals
74
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Parallel Evolution
o
Similar organisms develop similar adaptations
75
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Animal (& Fossil) Classification
Scheme based upon hierarchical arrangement of shared characteristics (e.g. similar to
rock & mineral scheme)
Kingdom
Phylum
o
Subphylum
Class
Order
Family
Genus
Species
For more details: “Ask a Biologist!”
Evidence for Evolution is found in things like:
Fossils
“Observable” Evolution
o
E.g. Moths
Animal Classification
Comparative Anatomy
o
o
o
Homologous Structures
Descent from common ancestor
E.g. Bone Structures
Analogous Structures
Structures that serve similar functions
Evidence of Convergence
E.g. Bird/Bat wings vs. Insect wings
Vestigial Structures
E.g. dewclaws on dogs
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Fossils
May preserve Body Parts
o
Soft body parts are rare
(or) Traces of Activity
o
Tracks, nests, etc.
o
Coprolites (feces)
Fossils may be Unaltered or Altered
Also, we talk about Molds (cavity of original organism) and Casts (filled-up cavities)
o
Molds & Casts may Internal or External
Unaltered Fossils
o
Insects in amber
o
Frozen
E.g. Wooly Mammoth
o
Mummified
o
Preserved in Tar Pits
E.g. “Jurassic Park Mosquito”
E.g. Labrea Tar Pits in L.A.
Altered Fossils
o
Permineralization = “Filling up the Holes”
o
Replacement
E.g. by SiO 2 (Quartz) or FeS 2 (Pyrite)
E.g. petrified wood
E.g. pyrite sand dollars
Fossil record is rich, but it’s only a small part of earth’s life record
Avg. species lifespan is 0.5 to 5 m.y.
If diversity of Cambrian (600m.y.) was similar to today, there have been 1 billion
species!
o
But only about 150,000 fossil species
“Chances of being fossilized is like winning Lotto 649”
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Learning Objectives for Week 6
Upon completion of this material, the student should understand the following.
The central claim of the theory of evolution is that today's organisms descended, with
modification, from ancestors that lived in the past.
In 1809, Jean-Baptiste de Lamarck proposed inheritance of acquired characteristics to
account for evolution.
In 1859, Charles Darwin and Alfred Wallace published their views on evolution and
proposed natural selection as the mechanism to account for evolution.
During the 1860s, Gregor Mendel demonstrated that variations in populations are
maintained rather than blended, as previously thought, during inheritance.
In the modern view of evolution, sexual reproduction and mutations in sex cells account
for most variation in populations, and populations rather than individuals evolve.
The fossil record provides many examples of macroevolution—changes resulting in the
origin of new species, genera, and so on—but these changes are simply the cumulative
effect of microevolution, which involves changes within a species.
Evolutionary trends such as size increase and changes in shells, teeth, and bones are
well known for organisms for which sufficient fossils are available.
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Important Terms for Week 6
allele
fossil
mutation
allopatric speciation
gene
natural selection
analogous structure
homologous structure
paleontology
artificial selection
inheritance of acquired characteristics parallel evolution
body fossil
macro evolution
phyletic gradualism
chromosome
mass extinction
punctuated equilibrium
cladistics
meiosis
species
cladogram
micro evolution
theory of evolution
convergent evolution
mitosis
trace fossil
deoxyribonucleic acid (DNA)
modern synthesis
vestigial structure
divergent evolution
mosaic evolution
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Web Resources for Week 6
These are some web resources that may be helpful for your studies during this week. You may
also want to consult the ongoing Forum related to web resources to see if additional websites
are recommended by other students or your instructor.
1. Evolution: A Journey into Where We’re From and Where We’re Going, PBS
http://www.pbs.org/wgbh/evolution/
2. Understanding Evolution: Your One-Stop Shop for Information on Evolution
http://evolution.berkeley.edu/
3. University of California Museum of Paleontology Evolution Wing
http://www.ucmp.berkeley.edu/history/evolution.html
4. The Talk.Origins Archive – Exploring the Creation/Evolution Controversy
http://www.talkorigins.org
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WEEK SEVEN: Catch-Up and Review!
No new reading, no new notes, this is a week to put your notes in order and get down to
reviewing and studying for the midterm exam next week. Of course, if you happen to be a bit
behind, this is the time to catch up too! You'll note that there is a new lab assignment for this
week, which is a continuation of the structural/historical exercises you have been doing for the
past couple of weeks. Make sure you pay attention to your instructor's comments in the news
forum concerning the content and format of your upcoming exam(s). As mentioned earlier,
your midterm exam may also include lab-related skills or those skills may need to be
demonstrated on a separate lab test. Your instructor will inform you about which applies to
you.
ASSIGNMENTS FOR WEEK SEVEN
Textbook Reading: Review all reading done up until this point!
Lab Book Reading: Review all reading done up until this point!
Notes: You should be consulting all the notes you have up until this point!
Lab Assignment: Structural & Historical Geology, Part 3
Other Assignment: Follow this simple recipe: Catch-Up, Review, Repeat.......
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Learning Objectives for Week 7
This week is for reinforcing and review of all the material from the first six weeks of the course,
including work on a new lab activity.
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Important Terms for Week 7
There are no new terms for this week. You should review all the important terms and your
notes from all the previous weeks.
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Web Resources for Week 7
There are no new web resources specific to new material, since this is a review week. However,
as usual, you may want to consult the ongoing Forum related to web resources to see if
additional websites are recommended by other students or your instructor.
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WEEK EIGHT: Midterm Exam Week
Well, here it is, midterm exam week already. Hasn't time flown! You have plenty on your plate
for this week with taking the exam and keeping caught up with the lab work. If you are lucky
enough to have everything complete and up to date, you can always jump ahead to the work
for next week and get a jump on that...
ASSIGNMENTS FOR WEEK EIGHT
Textbook Reading: No new reading assigned
Notes: No new notes suggested, however you should review prior to the midterm and, if you
so choose, start looking ahead to next week.
Lab Assignment: Structural & Historical Geology, Part 4
Other Assignment: MIDTERM EXAM
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WEEK NINE: The Ancient History of the Earth
Up to this point, we have been discussing many things that have to do with the history of the
earth, including geologic time, evolution, fossils, etc. Now is the point, however, where we
start our systematic look at this history in terms of what happened way back when, what
happened next, and so on and so forth. As you already know, it's a long story.
To begin with, you may need to refer back to the first chapter of your text, where the origin of
our universe and solar system are discussed. It shouldn't surprise us that the further back we
go, the murkier the story is to unravel.
Spectacular as the earliest events in our universe and solar system might have been, we just
don't have the time to really get into those mysteries (and even though we said earlier that "if
there's one thing geology has lots of, it's time," unfortunately it doesn't apply to us in this case).
We'll have to satisfy ourselves with starting our more in-depth look into our planet's history by
talking about the Precambrian earth and life history. Since that gets us back about four billion
years, it's still quite early in the story. And so, our time travel begins...........
ASSIGNMENTS FOR WEEK NINE
Textbook Reading: Chapter 19
Notes: You may wish to consult the notes labeled "History of our Solar System" and
"Precambrian Earth & Life History" and add to them as you see fit from your studying. You may
also wish to examine web resources listed on this site, in your textbook, in your lab book, on
the companion sites, or mentioned by the instructor.
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Lab Assignment: Complete all your Structural & Historical lab assignment work. Our
experience has shown that this week is often required for students to finish off some
uncompleted work and to generally get a better handle on the skills and techniques used in
these types of problems. Once you are done with this, you could choose to look ahead to the
Virtual Field Trip assignment, but that is not officially on the agenda until next week.
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History of our Solar System
First, the Universe
o
“Big Bang” ~13-20 billion years ago
Time & Space set at Zero: “No Before”
Evidence?
Universe is expanding
Background Radiation above Absolute Zero
“The Stuff of Star Trek”
There are other theories
o
i.e. Inflationary Scenario = Many Universes
Solar System
Rotating cloud
Condensing to disk with counter-clockwise rotation
Gravity forms Sun & Planets
Process essentially began ~4.6b.y.
o
Meteorite Evidence
Stones: Fe & Mg, Silicates, incl. Basalt
Irons: Fe & Ni
Stony-Irons: Combinations
2 Planet "Types"
Jovian (outer planets)
o
Consisting of gases
Condense at low temps.
Terrestrial (inner planets)
o
Rocks & Metals
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o
Condense at high temps.
Perhaps “similar” history to Earth
Volcanism
Impact Cratering
All differentiated into Core, Mantle, Crust
o
Tectonics on Venus & Mars may be of “Hot Spot” type
o
Significant Climate differences
o
CO2 Important
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Asteroids
Asteroid Belt
o
Conventional Wisdom = “Shattered Planet”
o
Could be due to “tug of war” between Sun & Jupiter
“Killer Asteroid”
o
Impact structures ~65 m.y.
Dinosaur extinction?
K-T Boundary (Cretaceous-Tertiary)
Yucatan (170km diam.), Caribbean (115 km diam.), Iowa (35 km diam.)
Also Gulf Coast evidence
The Moon
Byproduct of Collision 4.4-4.6b.y.?
o
Active volcanism as recently as 900m.y.
o
But if the core is Nickel, then unlikely
Evidence from “dark side”
Current Earth Structures ~3.96b.y.
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Precambrian Earth & Life History
Moon: Byproduct of Collision?
o
4.4 to 4.6 b.y.
o
Active volcanism up until ~900m.y.
o
Since no erosional /tectonic forces on Moon, Moon ~ View of Early Earth
When did Earth’s Plate Tectonics begin??
o
“Current” Earth structures ~ 4b.y.
Original Earth ~ 4.6 b.y.
o
Hot, perhaps molten
o
Lots of CO2, no O2
o
No rain or liquid water
By 3.96b.y.
Primitive Crust & Continents
Acasta Gneisses = oldest rocks in the world = 3.962 b.y.
o
200 mi N. of Yellowknife
o
Discovered May 1984
Zircon crystals from Australia = 4.276 b.y.
Probably no 4 to 4.5 b.y. rocks on Earth due to plate tectonics
By 3.5 b.y., “Life”
Time Periods
0 → 545 m.y. = Phanerozoic Eon
o
Includes Paleozoic, Mesozoic, Cenozoic Eras
Precambrian = Older than 545
545 → 2500 m.y. = Proterozoic Eon
o
Includes X, Y, & Z Eras
2500 → ~4000 m.y . (= 4 b.y.) = Archean Eon
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Supercontinent Cycle
= Wilson Cycle
o
A: Initial Rifting of Continent
o
Similar to Atlantic Ocean today
C: Passive Margins “switch” to active subduction zones
o
Similar to East Africa today
B: Creation of ocean basin with Passive Margins near continents
o
~ 500 m.y . cycle
Similar to W. Coast of S. Am. Today
D: Continents collide together
o
Similar to Himalayas today
Cratons & Shields
Each continent has a stable core area = Craton
o
Craton = Exposed & Covered Precambrian Shield
E.g. Canadian Shield
Consists of a variety of smaller cratons, or geologic provinces, e.g.
Slave Province
Includes Archean & Proterozoic rocks
Archean Rocks (>2500 m.y.)
o
Granite/Gneiss
o
“Greenstone” Belts
(Unconformity)
Proterozoic Rocks
o
Lots of undeformed sedimentary
Archean Rocks
Granites
Gneisses
Greenstone Belts
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o
Linear Synclinal bodies
o
Have typical rock sequences (= Archean Sedimentary rocks)
E.g. Graywacke (sandstone with clay)
E.g. Argillite (slightly metamorphosed shale)
E.g. Sullivan Mine rocks (which are actually Proterozoic)
From Turbidity currents?
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Proterozoic 545 m.y. → 2500 m.y.
Crust accretes around Archean core forming, over time Laurentia (~N. Am. & Greenland)
Includes a variety of episodes, e.g.:
o
Grenville Orogeny
o
Midcontinent Rift
By Late Proterozoic , Laurasia & Gondwana “supercontinents”
1.96 b.y. = oldest ophiolite
o
Oldest evidence of ocean-continent collision with subduction
Quartzite-Carbonate-Shale “Assemblage” = Evidence of passive margins & inland seas
Also evidence of Glaciation
CO2 important
Atmospheric Changes
Archean Outgassing from volcanoes allowed development of early atmosphere &
oceans
Not much Oxygen at first
Photosynthesis increased O2 level over time
o
Largely due to blue-green algae = Stromatolites
E.g. modern-day Shark Bay, West Australia site
2.5 to 2.0 b.y . = formation of Banded Iron Formations
o
90% of world’s iron ore
o
Increase of O 2 caused iron to precipitate out
Also, Red Beds appeared due to oxygen
Precambrin resources include:
o
BIF
o
Gold (S. Africa, U.S., Canada)
o
Platinum & Chrome
o
Nickel, e.g. INCO at Sudbury
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WEEK TEN: Paleozoic Earth History
So we've looked, and continue to look, at the Big Picture called Plate Tectonics. We've looked
at many of the specific structural features related to plate tectonics, including faulting, folding,
the creation of unconformities and so on. We've briefly examined what was going on in
Precambrian time. Now it's time to examine in more detail how all of this background helps
explain the tectonic events that were happening in the Paleozoic, a geologic era which
encompassed the time from around 540 million years ago until around 250 million years ago.
During the earliest part of this era, known as the Cambrian Period, it is thought that a bunch of
continents were aligned roughly along the equator. By the end of the era, we think that the
supercontinent of Pangaea had formed. Obviously, lots of things must have been happening in
between, including the formation of what we know as the Appalachian Mountains, which
extend from the southeast United States up into Newfoundland. Speaking of Newfoundland, it
turns out that the newest Canadian province has a very rich geologic past, and as such
represents a great case study in all things tectonic. Everything from chunks of Europe being left
behind on the east side, to old volcanoes being squished into the middle, to slabs of ocean crust
being welded onto the west side, Newfoundland has it all. In fact, some of the outcrops found
in the west are among the most famous in the world. Guess they don't call it "The Rock" for
nothing!
ASSIGNMENTS FOR WEEK TEN
Textbook Reading: Chapter 20
Notes: You may wish to consult the notes labelled "Paleozoic Earth History" and add to them as
you see fit from your studying. You may also wish to examine web resources listed on this site,
in your textbook, in your lab book, on the companion sites, or mentioned by the instructor.
Lab Assignment: Design a Virtual Field Trip
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Other Assignment: Note that the "Design a Virtual Field Trip" Assignment is a Special Lab
Assignment which entails more work than a regular lab assignment and which is also worth
more in terms of your final mark for the course.
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Paleozoic Earth History
Paleogeographic Maps: Putting landmasses at correct long. & lat. and at correct
orientation. Based on evidence from:
o
Paleomagnetism
o
Fossils
Where, when, distribution
o
Tectonics
o
Paleoclimatic evidence
We have both polar wandering and polar reversal
Remember that configuration of continents has a large effect on climate
Remember, we have:
o
A) Shield
o
B) Covered Shield (~platform)
o
(and now) C) Mobile Belts
Mountain-building episodes along edges of more stable cratons
During Cambrian Period (~500m.y.), 6 “continents” roughly along equator
By Permian Period (~250m.y.):
o
Supercontinent of Pangaea
o
Superocean of Panthalassa
Much Paleozoic sedimentary rock deposition included Transgression (Sea-level rise) or
Regression (Sea-level lowering) of Epeiric Seas (shallow seas over craton)
Remember, Transgression typically includes an upward sandstone-shale-carbonate
facies change
Regression often involves an Unconformity at top of “ Cratonic Sequence” (= a large
group of rock formations ~ a Supergroup
Transgressions (e.g. Sauk Sequence) & Regressions are assoc. with sea-level change due
to glaciations & tectonics
Try to remember the concepts of sedimentary environments:
o
Sandstones
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o
Higher energy environment, perhaps terrestrial as opposed to marine
E.g. from Tippecanoe Sequence
Carbonates
E.g. Barrier Reefs
o
o
Devonian reef complexes
Evaporites
E.g. enclosed basins
E.g. western Canadian potash deposits
Shales
E.g. from fine muds & turbidites
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Cambrian
o
Famous for many fossils
E.g. Burgess Shale
Ordovician & Silurian
o
i.e. Tippecanoe time
o
Taconic Orogeny = first major Appalachian Mountain building
o
These mountains also started providing sediment for Western epeiric sea
Pennsylvanian (part of Carboniferous)
o
Transgression & Regression cycles over time involving marine & non-marine
deposits
Cyclothem = Repeating Sedimentary Sequence
Also, “Ancestral Rockies”
o
During erosion, red sandstone produced
E.g. Colorado’s “Red Rocks”
Famous music venue
Permian
o
Reef & Evaporite deposits
e.g. Coal Beds
E.g. Guadaloupe Mountains of Texas
During middle-late Paleozoic, Baltica & Laurasia collide
Newfoundland & Gros Morne National Park: A classic case history!
1+ Billion years ago
o
Eastern edge of Canadian Shield = present day portions of Long Range
Mountains in Nfld
o
Gneiss, Schist, Granite
Part of super-continent
650-600m.y.
o
Super-continent starts rifting apart (similar to Red Sea today)
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Creation of Iapetus Ocean & Mid-Iapetus Ridge
Igneous Dikes fill some of the rifting cracks
New ocean crust (pillow basalts, etc.) created = future ophiolite rocks of
Gros Morne
600-500m.y. = Passive margin along east coast (similar to N.Am east coast today)
o
Sediments accumulate as continental shelf deposits 100km out (muds → shale)
o
1km-thick carbonate bank forms
Often, chunks of bank broke off and tumbled down continental slope,
later becoming limestone breccia deposits found in Gros Morne today
o
100s of km offshore, volcanic seamounts form over hot spot/mantle plume
(similar to Hawaii today)
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500-450m.y. = Plate motion reverses
o
Iapetus Ocean begins to close
o
North American plate (incl. Nfld.) gets subducted far out to the east (this was
unusual; usually it happens closer to the continent)
Island-arc volcano chain created (similar to Pacific island chains of today)
o
Today, these rocks are much of central Nfld.
Compression causes lots of thrust faulting and stacking of pre-existing rocks (e.g.
the limestone breccia)
In places, a melange is created (similar to Cache Creek melange in BC, but
that’s another story!)
450-350m.y. = collision of North America with Eurasia/Africa
o
The end of the Iapetus Ocean
o
“zippered” closed from N to S
Caledonide Mountain System created
Includes Appalachian Mountains, plus mtns. in Great Britain &
Scandinavia
o
W. Nfld. rock structures still show this sw -ne orientation
A new super-continent, Pangaea , is created, with Nfld. In the middle
Part of the collision involved ocean crust & mantle being forced up onto
land, rather that the usual situation of being subducted
Thus, the famous ophiolite rocks of Nfld.
200m.y. to today = The breakup of Pangaea, and the birth of the Atlantic Ocean
o
Initial split occurs 500km east of earlier Iapetus Rift
This leaves a “chunk of Europe” occupying eastern Nfld. = Avalon
Peninsula
Central Nfd . = island arc volcanics & Iapetus sediments
Western Nfld. (i.e. Gros Morne ) = former continental margin rocks,
ophiolites , etc
o
Most recently, glaciation , plays a key role in sculpting Gros Morne
E.g. Western Brook Pond = a very famous fiord
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Learning Objectives for Week 10
Upon completion of this material, the student should understand the following.
Six major continents were present at the beginning of the Paleozoic Era, and that plate
movement during the Paleozoic resulted in continental collisions leading to the
formation of the supercontinent Pangaea at the end of the Paleozoic.
The Paleozoic history of North America can be subdivided into six cratonic sequences,
which represent major transgressive-regressive cycles.
During the transgressive portions of each cycle, the North American craton was partially
to completely covered by shallow seas in which a variety of detrital and carbonate
sediments were deposited, resulting in widespread sandstone, shale, reef, and coal
deposits.
Mountain-building activity took place primarily along the eastern and southern margins
(known as mobile belts) of the North American craton during the Paleozoic era.
In addition to the large scale plate interactions during the Paleozoic, microplate and
terrane activity also played an important role in forming Pangaea.
Paleozoic-age rocks contain a variety of important mineral resources.
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Important Terms for Week 10
Absaroka sequence
cyclothem
organic reef
Acadian orogeny
epeiric sea
Ouachita mobile belt
Ancestral Rockies
Franklin mobile belt
Ouachita orogeny
Antler orogeny
Gondwana
Panthalassa Ocean
Appalachian Mobile Belt
Hercynian-Alleghenian orogeny Queenston Delta
Baltica
Iapetus Ocean
Sauk Sequence
Caledonian orogeny
Kaskaskia sequence
sequence stratigraphy
Catskill Delta
Kazakhstania
Siberia
China
Laurasia
Taconic orogeny
clastic wedge
Laurentia
Tippecanoe sequence
Cordilleran mobile belt
mobile belt
Transcontinental Arch
cratonic sequence
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Web Resources for Week 10
These are some web resources that may be helpful for your studies during this week. You may
also want to consult the ongoing Forum related to web resources to see if additional websites
are recommended by other students or your instructor.
1. University of California Museum of Paleontology
http://www.ucmp.berkeley.edu/
2. The Field Museum of Natural History Exhibits
http://www.fieldmuseum.org/exhibits
3. Grand Canyon Geology
http://www.kaibab.org/geology/gc_geol.htm
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WEEK ELEVEN: Paleozoic Life History
Most agree that very significant developments in the history of life did indeed happen in the
Precambrian. However, we use the term "Cambrian Explosion" for a reason, and that is
because it was during the Cambrian that life really seemed to blossom on Earth. Not only
trilobites, but also other strange and wonderful creatures started to inhabit the oceans. This
week we will look at this explosion of life in the Cambrian, and follow the story along until the
end of the Paleozoic Era, known as the Permian Period. As often happened in geological time,
the end of the Permian was noted by a mass extinction of species, which of course opened the
door to new species to occupy the niches left behind..........
If you mention Canada to a geologist anywhere in the world, particularly a geologist interested
in fossils, chances are that the first thing to enter their mind will be the Burgess Shale. That's
because the Burgess Shale is by far the most famous fossil site in Canada, and to many people
it's the most significant geological site, period, in our country. Australia may have the famous
stromatolites at Shark Bay, but we have the Burgess Shale. In case you don't already know, the
Burgess Shale is located inside Yoho National Park, near the town of Field, British Columbia.
The story of the Burgess Shale is a great one, starting with the fact that the fossils there were
discovered in the early 1900s by possibly the only the man in the world who might've been able
to recognize their significance at the time. You see, he was Charles Walcott, and he happened
to be on holiday from his job as head of the prestigious Smithsothian Museum. The fossils were
collected, studied, stored, examined, forgotten, re-examined, stored, forgotten again, and then
about twenty years ago a fellow from Harvard named Stephen Gould wrote a book about them
entitled "Wonderful Life." Well, he and his book made it to the cover of Time Magazine, and he
went on to even arguably bigger fame by voicing himself on an episode of "The Simpsons."
(Bart found a fossil that needed examining and, well, that's another story. The point is, do you
know of any other paleontologist who was ever on the Simpsons?) Walcott's claim was that,
hidden in the rocks above Field, a story about the whole history of life on earth could be
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deciphered. It all caused quite the stir. There was even one "insignificant worm" fossil named
Pikaia that may well have been one of the first know chordates. You should check this one out!
Aren't we lucky that this locale happens to be in our own Beautiful British Columbia!
ASSIGNMENTS FOR WEEK ELEVEN
Textbook Reading: Chapter 21
Notes: You may wish to consult the notes labelled "Paleozoic Life History" and add to them as
you see fit from your studying. You may also wish to examine web resources listed on this site,
in your textbook, in your lab book, on the companion sites, or mentioned by the instructor.
Lab Assignment: Fossils, Part 1 (Note that this is Part 1 of a 3-Part Project)
Other Assignment: Participate in the "Pick Your Favourite Burgess Shale" Discussion Forum.
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Paleozoic Life History
“Life” on Earth
o
C, H, N, O, plus “spark” (UV radiation and/or lightning)
First synthesized Amino Acids in 1950
Miller Apparatus
Prokaryotic → Eukaryotic Cell
Single-celled → Multi-celled soft bodied > 570m.y.
Hard Parts appear in Cambrian
o
Predator protection
o
Muscle support: Allows size increase
o
Increased locomotor skills
Marine Life
o
Plankton = Float
o
Nekton = Swim
o
Benthos = On Sea Floor
Feeding Groups
o
Suspension
o
Herbivores
o
Carnivores
o
Sediment-deposit Eaters
Trophic Levels
o
Primary Producers
o
Primary Consumers
o
Secondary……..
o
i.e. the “Food Web”
o
(Process includes decomposing bacteria)
Transition from Water to Land: Barriers
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Drying Out: Dessication
Reproduction
Gravity (i.e. lack of skeletal support)
Lungs vs. Gills
(For Plants) Sunlight Tolerance
Cambrian
o
“Explosions” & “Extinctions”
o
Mid-Cambrian = Burgess Shale
o
Are Extinctions cyclical or random
E.g. 26 m.y . cycle?
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Ordovician
o
Lots of shelled life
o
Large-scale reefs
o
Again, extinctions
Silurian & Devonian
Fauna variety
Extensive Reefs
o
Are corals tied in with the greenhouse effect?
Glacial Advance
Sea-Level drop
Reefs exposed
CaCO3 reacts with CO2 and removes it
Things cool down even more
(similar idea to “Albedo Story”)
Paleozoic Plants
Had to overcome similar problems to animals in sea to land transition (i.e. Dessication ,
Gravity, Reproduction, Sunlight Tolerance)
Fossil “problem” with plants = Carbonization
Ordovician = First land plants in fossil record
o
Marine algae → Mud Flat Environment → Land
Evolution of Vascular Tissue important
By Devonian → Forests
By Carboniferous → Vast Coal Swamps
By Permian (dry) → Gymnosperms
Nature of Things: Burgess Shale
“1% Difference between “us” & chimps!”
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Burgess Shale deposit
o
530m.y. ago in 300 ft of water (no oxygen)
Turbidity flow or sediment from the side?
Discovered in 1909 by Walcott, “The one man in the world who would
recognize their significance”
Serendipity?
Recent evidence suggests life then was less primitive than thought
Similar fauna to China (discovered in ’84) and Greenland
o
1966 GSC study to re=open the Burgess Shale
o
Therefore, Burgess Shale = Representative of World
Briggs (Arthropods) & Morris (Worms) from Cambridge
Squished animals were “Enlarged” in “Bizarre” organisms
o
E.g. “The Swiss Army Knife of Arthropods”
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However, only 3 arthropod body types survived the Cambrian
Perhaps environmental changes (e.g. glaciers, volcanoes) went beyond the range of
Cambrian adaptability & they went extinct
One lucky winner was an “insignificant worm,” a chordate ancestor of humans = Pikaia
Another survivor = Coelacanths
o
Thought to have become extinct in Cretaceous, but caught off S. Africa in 1938!
Fish Lobes → Arms & Legs
Gould (Harvard) quotes:
Survival wasn’t necessarily of the most superior animals but rather due to “winning the
biggest lottery ever held”
“If the pond dries up, they’re dead!”
“The motor for new body designs was turned off”
“We’re here due to good luck”
o
Humans neither Predictable nor Preordained
The “Tree of Life” vs “Shrub of Life”
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Learning Objectives for Week 11
Upon completion of this material, the student should understand the following.
Animals with skeletons appeared abruptly at the beginning of the Paleozoic Era and
experienced a short period of rapid evolutionary diversification.
During the Paleozoic Era, the invertebrates experienced times of diversification followed
by extinction, culminating in the greatest recorded mass extinction in Earth's history at
the end of the Permian Period.
Vertebrates first evolved during the Cambrian Period, and fish diversified rapidly during
the Paleozoic Era.
Amphibians first appear in the fossil record during the Late Devonian, having made the
transition from water to land; they became extremely abundant during the
Pennsylvanian Period when coal-forming swamps were widespread.
The evolution of the amniote egg allowed reptiles to colonize all parts of the land
beginning in the Late Mississippian.
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Important Terms for Week 11
acanthodian
herbivore
protorothyrids
amniote egg
labyrinthodont
sediment-deposit feeder
benthos
nekton
seedless vascular plant
bony fish
nonvascular
suspension feeder
carnivore-scavenger
ostracoderm
therapsid
cartilaginous fish
pelycosaur
vascular
chordate
placoderm
vertebrate
crossopterygian
plankton
gymnosperm
primary producer
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Web Resources for Week 11
These are some web resources that may be helpful for your studies during this week. You may
also want to consult the ongoing Forum related to web resources to see if additional websites
are recommended by other students or your instructor.
1. Paleozoic Era Paleobiology
http://www.fossilmuseum.net/Paleobiology/Paleozoic_paleobiology.htm
2. The Burgess Shale Site
http://www.burgess-shale.bc.ca
3. Strange Creatures—A Burgess Shale Fossil Sampler
http://paleobiology.si.edu/burgess/index.html
4. A Guide to the Eight Orders of Trilobites
http://www.trilobites.info/
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WEEK TWELVE: The Mesozoic
The Mesozoic Era includes what has probably become the most famous Period in geologic time,
namely the Jurassic. Kids of all ages have always been fascinated with dinosaurs, and thanks to
Michael Crichton and Stephen Spielberg almost everyone knows that the Jurassic is somehow
associated with these "terrible lizards." While many other events were also unfolding during
the Mesozoic, it is the rise, and fall, of the dinosaurs that captures the imagination. Even if you
haven't taken any geology courses before, there is a good chance that you've heard something
about the extinction of the dinosaurs at the end of the Cretaceous Period, and you also likely
have heard that a comet or giant meteorite may have been involved. Whatever happened, the
dinosaurs did become extinct and it's a good thing for us that they did or we might well not be
talking about them now.
ASSIGNMENTS FOR WEEK TWELVE
Textbook Reading: Chapter 22
Notes: You may wish to consult the notes labelled "Mesozoic" and add to them as you see fit
from your studying. You may also wish to examine web resources listed on this site, in your
textbook, in your lab book, on the companion sites, or mentioned by the instructor.
Lab Assignment: Fossils, Part 2
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Mesozoic
245 → 66m.y.
“Age of Dinosaurs”
Breakup of Pangaea
o
o
o
o
Triassic
Separation of N. Am. from Africa
Separation of N. Am from S. Am.
Jurassic
Antarctica, India, Australia from S. Am. & Africa
India from Antarctica & Australia
Cretaceous
S. Am. From Africa
Europe & Africa Converging
Cenozoic
Greenland separates from N. Am. & Europe
Effects of Breakup
Global Climatic & Atmospheric Patterns change
o
E.g. Temp. Gradient from Equator to Poles increased
Due to more land in high latitudes
(Overall temp. high)
Increased sea-floor spreading, esp. during Cretaceous
o
Sea Level Rise
o
Transgression
N. America was mostly above sea level, except during Transgressions
Mesozoic Rocks of Western N. America
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Both Continental & Marine depositional environments
Tectonics very important in our region during Mesozoic and on into Cenozoic
o
Laramide Orogeny → Rocky Mtns.
o
Ocean-Continental plate convergence
o
Folds
Faults
Batholith emplacements
Accreted Terranes
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Mesozoic Life History
Gymnosperms replaced by Angiosperms (flowering plants) as dominant plant species
o
Over 90% of land plant species today
Small dinosaurs → Birds
Earliest mammals from Late Triassic
o
Marsupials
o
Placentals
Mesozoic Mass Extinction
Had Dinosaurs “time come?”
Or……
Catastrophic Event (e.g. Meteorite)
Or…….
Both
o
Serendipity?
K-T Impact
Proposed in 1980 by Alvarez
Recent research: “Once in a billion years event?”
o
i.e. Bigger than originally thought
But at the same time, research shows evidence of arctic dinosaurs
o
i.e. animals already adapted to cold & dark already
Up to 300km diameter = Chicxulub Crater
Fossils of smaller, non-migrating dinosaurs
So, why are dinosaurs extinct while other climate-sensitive species (e.g. turtles)
survived??
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o
Perhaps it wasn’t simply cold & dark that “did the dinosaurs in”
o
Perhaps it was acid rain, or the long length of cold & dark
Equal weight must be put on Survival , not just Extinction
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Learning Objectives for Week 12
Upon completion of this material, the student should understand the following.
The Mesozoic breakup of Pangaea profoundly affected geologic and biologic events.
Most of North America was above sea level during much of the Mesozoic Era.
A global rise in sea level during the Cretaceous Period resulted in an enormous interior
seaway that divided North America into two large landmasses.
Western North America was affected by four interrelated orogenies that took place at
an oceanic-continental convergent plate boundary.
Terrane accretion also affected the Mesozoic geologic history of western North America.
Marine invertebrates that survived the Permian extinction event diversified and
repopulated the Mesozoic seas.
Land-plants changed markedly when flowering plants evolved during the Cretaceous.
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Important Terms for Week 12
angiosperm
ichthyosaur
plesiosaur
Archaeopteryx
iridium anomaly
pterosaur
archosaur
Laramide orogeny
quadrupedal
bipedal
marsupial mammal
Saurischia
Cordilleran orogeny
monotreme
Sevier orogeny
Cretaceous Interior Seaway
mosasaur
Sonoma orogeny
cynodont
Nevadan orogeny
Sundance Sea
ectotherm
Ornithischia
terranes
endotherm
placental mammal
therapsid
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Web Resources for Week 12
These are some web resources that may be helpful for your studies during this week. You may
also want to consult the ongoing Forum related to web resources to see if additional websites
are recommended by other students or your instructor.
1. Top 10 Misconceptions About Dinosaurs
http://paleobiology.si.edu/dinosaurs/info/misconceptions/main.html
2. The Mesozoic Era
http://www.ucmp.berkeley.edu/mesozoic/mesozoic.html
3. What Killed the Dinosaurs?
http://www.ucmp.berkeley.edu/diapsids/extinction.html
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WEEK THIRTEEN: The Cenozoic
In one sense, we are getting near the end of the story, in that the Cenozoic is the most recent
Era in the Geologic Time Scale. On the other hand, we're still talking about over 60 million
years of time! The Cenozoic may have come in with a bang, literally (remember the dinosaur
extinction story?), and the evidence of that bang can be found throughout the world in a thin
layer of clay marking what is known as the K-T boundary (K-T being short for CretaceousTertiary, which may be a bit confusing since Cretaceous starts with the letter C but is
designated with a K to distinguish it from the Cambrian period, and further confusing since
many sources, including your text, rarely use the term "Tertiary" these days).
Since K-T boundary time, plenty of other things have happened. The Rocky Mountains finished
being forming in the Laramide Orogeny, and India has slammed into Asia creating the
Himalayas, just to name a couple of things. More recently, glaciers around the world have
carved up mountains into the alpine peaks we know and love. And last but certainly not least,
humans came along to become the dominant species of our time. No one knows how the
Cenozoic will end since technically it is still going on. Some suggest we are undergoing a mass
extinction as we speak, perhaps a mass extinction that will include the demise of our own
species. But we won't dwell on that rather morbid thought!
ASSIGNMENTS FOR WEEK THIRTEEN
Textbook Reading: Chapter 23
Notes: You may wish to consult the notes labelled "Cenozoic" and add to them as you see fit
from your studying. You may also wish to examine web resources listed on this site, in your
textbook, in your lab book, on the companion sites, or mentioned by the instructor.
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Lab Assignment: Fossils, Part 3
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Cenozoic
Quaternary Period
o
Holocene Epoch (present-0.01m.y. = 10,000 years)
o
Pleistocene Epoch (to 1.6. m.y .)
Tertiary Period
o
Pliocene Epoch
o
Miocene Epoch
o
Oligocene Epoch
o
Eocene Epoch
o
Paleocene Epoch (to 66 m.y .)
Pangaea split-up continued and accounts for present-day continental distribution
Orogenic Activity mainly in two belts:
o
Alpine-Himalayan (i.e. Europe & Asia)
Pyrennes , Alps, etc. + Himalayas
“Alpine Orogeny ”
Africa collides with Eurasia
o
Mountains in S. Europe, N. Africa, Middle East
India
Separated from Gondwana
Moved North
Collided with Asia
Caused uplift of Himalayas
Circum-Pacific (i.e. Pacific Ring of Fire)
Cascades, Aleutians, Japan, Andes, etc.
North American Cordillera
Mountains from Alaska to Mexico
During Cenozoic:
o
Laramide Orogeny Deformation
Late-Cretaceous to Eocene
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o
70m.y. → 40m.y.
Creation of Rocky Mountains
Also Extensional Tectonics
Basin & Range province (Nevada)
Numerous Horsts & Grabens
Rocky Mountain Trench
o
Columbia Flood Basalts (Miocene)
o
Pleistocene Tectonics
Sierra Nevadas (California)
Grand Tetons (Wyoming)
Recent Basin & Range Faulting, e.g. 1983 Borah Fault quake in Idaho
Also in Pleistocene
o
Intrusive & Extrusive volcanism
o
Uplift & Erosion (e.g. in Appalachians)
o
Glaciation
North American Plate collided with Farallon Place
o
Low-Angle Subduction
Numerous Thrust Faults in the Rockies
E.g. Lewis Overthrust
Led to klippes such as Crowsnest Mountain & Chief
Mountain (Montana)
As Farallon subduction ended, in California & South, Transform Boundaries took over
o
E.g. San Andreas Fault
Current Juan de Fuca Plate subduction is the last remnant of Farallon
o
Steeper subduction than Farallon
Thus, more volcanism throughout Cenozoic
Cascade Range volcanics (Mt. St. Helens, etc.), PliocenePleistocene
Miocene (24m.y. → 5 m.y .) Columbia Flood Basalts
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"Where Terranes Collide"
Chris Yorath
Cordillera = most of Western Canada
Currently, Juan de Fuca plate colliding with N. Am. Plate @ 4cm/yr
1700m.y. → 750 m.y ., sediments from N. Am. & Australia & Antactica found in
Waterton Park
Salmon Arm = western edge until ~180m.y.
Terranes & Accreted Terranes
Wrangellia Terrane (part of Insular Superterrane)
o
Vancouver Island
o
Queen Charlottes
o
Volcanics & limestone
Cache Creek melange (“glue”)
Omineca Belt = Metamorphics
o
Shuswap metamorphics
160m.y. → 100m.y., N. Am. hits Insular Superterrance
o
o
Numerous thrust faults
o
E.g. Mt. Rundle
Foothills Strata
Due to erosion from Rockies
Glacial activity
o
Results in Coast Range
Main Story = Rockies
o
E.g. Revelstoke
E.g. “Big Rock” erratic at Okotoks
Mt. Garibaldi & Cascade volcanics
Other North American Regions
Colorado Plateau
o
Uplift & erosion
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o
Not much deformation
o
E.g. Grand Canyon, Zion, Bryce Canyon, etc.
o
“Gentle” Late Tertiary uplift led to current canyon erosion
Basin & Range
o
Crustal stretching & faulting
o
Normal Faulting = Horsts & Grabens
Great Plains
o
Sediments from Laramide Orogeny & from Pleistocene Glaciations
Flat!
Eastern N. Am.
o
Passive margin since early Mesozoic, but current topography is due to Cenozoic
uplift & erosion ( isostacy important)
Quaternary Period
E.g. Qal (usually yellow on maps)
Holocene Epoch = recent 10,000 years
Pleistocene Epoch = 10,000 years to 1.6 m.y.
o
Glaciers periodically covered 30% of earth
o
~20 warm-cold cycles
o
Climate “belts” compressed along equator
o
Many pluvial lakes
o
Changing sea levels
o
Isostatic subsidence & rebound
When did the earth start cooling?
“Great Ice Age” = 2 m.y ., but it started 40m.y. due to:
o
Plate motion affected global ocean circulation patterns
Warm tropical water movement inhibited
As landmasses moved poleward , temperatures decreased due to land
not holding heat as well as water
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WEEK FOURTEEN: Putting Things Into Perspective
The last chapter in your textbook is a short one, but it refers to some issues that could take a
lifetime to discuss. Agriculture, natural hazards, ozone depletion, acid rain and other
environmental topics are all mentioned in brief. These are indeed some of the big issues of the
day worldwide, and any one of them could be studied at length. Many university courses are
devoted to these topics, both from a science perspective and also often from an
arts/humanities perspective. Unfortunately, we don't have the time (there's that time factor
again!) to really get into it, but you should certainly finish this course by at least thinking about
how all your new knowledge fits into the many discussions that are happening between world
leaders today.
From your point of view as a student, however, the more pressing reality may be the upcoming
final exam which is happening next week. Obviously, this is a week to continue in earnest your
review of the course materials. That should keep you busy....
ASSIGNMENTS FOR WEEK FOURTEEN
Textbook Reading: Chapter 24
Notes: You may wish to consult the notes labeled Environment & Resources" and "Final Exam
Review" and add to them as you see fit from your studying. You may also wish to examine web
resources listed on this site, in your textbook, in your lab book, on the companion sites, or
mentioned by the instructor.
Lab/Other Assignments: Please chime into the final Discussion/Forum for the course, "The Big
Issues of the Day." Also this is also the time to finish up all assignments that can still be turned
in! As always, consult with your instructor concerning exact due dates and methods of getting
your assignments in for marking.
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“Big Names” related to Geology
Hutton: Uniformitarianism
Darwin: Evolution
Mendel: Genetics
Wegener: Continental Drift
o
(→ Plate Tectonics)
Lovelock: Gaia Hypothesis
Malthus: Malthusian Doctrine
o
Overpopulation = #1 cause for concern
o
Leads to competition for resources
o
War, Famine, Disease will decimate the population
Issues Related to Geology
Natural Hazards
o
Volcanoes, Quakes, Landslides, Floods, Storms
Pollution
o
E.g. burning of fossil fuels
o
E.g. mine waste
o
E.g. disposal of Nuclear Waste
o
E.g. leakage into groundwater
o
NIMBY considerations
Global Change
o
Global warming, acid rain, ozone
o
Large ecosystem damage
E.g. Aral Sea case
Overpopulation = #1 Issue?? – Birth control, famine, food distribution
Resources
Coal
o
“200 year supply?”
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o
Is it economic
o
Saudi Arabia has 60% of proven reserves
o
Russia has huge potential
o
BC offshore oil???
Oil
Natural Gas
o
Transport is big issue
Metals (“hard rock” geology)
o
Price is everything
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Final Exam Review
GEOL 106 “Themes”
Plate Tectonics
o
Evidence For
o
Boundary Types
o
Supercontinent Cycle
o
Movement of Continents/Plates
o
Paleogeographic Maps
Today’s pattern
Craton, Shield
Structural Geology
o
Cross-sections, e.g. Ophiolites
i.e. Lab-type problems
Strike, dip, faults, block diagrams, etc.
Review handout exercises
Geologic Time
o
Geologic Time Scale
o
Relative & Absolute Age Dating
o
Evolution
o
Darwin, Mendel
Punctuated Equilibrium
Phyletic Gradualism
Divergent, Convergent, Parallel
Fossils
Incl. identification (~mini lab test)
o
i.e. phylum, class, example
(fossil labs due at start of exam)
(General) overview of earth & life history
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"Special Studies"
Early Processes
o
E.g. Stromatolites
o
E.g. Banded Iron Formation
Newfoundland
Burgess Shale
Mass Extinctions
o
E.g. “K-T Impact
B.C. and region
o
o
Rockies
Laramide Orogeny
Rocky Mountain Trench
Accreted Terranes
“Where Terranes Collide”
o
Sullivan Mine
o
Columbia Basalt Plateau
o
Cascade Range
o
Basin & Range
Bring to Exam
o
Ruler
o
Protractor
o
Coloured pencils
o
Pencil
o
Eraser
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Learning Objectives for Week 14
Upon completion of this material, the student should understand the following.
Earth is a dynamic planet that has changed throughout its 4.6-billion-year history and it
continues to change.
Developing your skills as a critical thinker is one objective of this book and of your postsecondary education.
You can see examples of geologic features or processes everywhere.
The Agricultural Revolution was a major change in human history that allowed
occupational specialization, increased populations, and a better standard of living.
Because Earth is a dynamic planet it produces geologic hazards such as earthquakes,
landslides, volcanic eruptions, and floods, which are threats to humans.
Some of the pressing environmental issues today are acid rain, ozone depletion, global
warming, and rising sea level.
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Important Terms for Week 14
acid rain
geologic agent
ozone depletion
Agricultural Revolution
geologic hazard
radon
environmental geology
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Web Resources for Week 14
You may want to refer back to earlier web resources which you have looked at during the
course. You may also want to consult the ongoing Forum related to web resources to see if
additional websites are recommended by other students or your instructor.
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DISCUSSION FORUM: The BIG Issues of the Day
OK, we are pretty much at the bitter end save for the big test next week. Still, we should have
the time for one last forum for discussion. Much of this course has been involved with the nuts
and bolts of physical geology. However, there is a bigger world out there with some crucial
issues that affect us all. Geology in the broad sense has an important role to play in many of
these issues, whether the issue is global warming, fossil fuels, or even something like
population. This forum is your last kick at the cat for a discussion to bring up what big issue(s)
you think are most important and why. Hopefully your interest in and also analysis of these
issues has been stimulated over the last few months of this course. Have any of your opinions
changed? Are you more or less concerned about some of these issues than before? Tell us
what you think!
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WEEK FIFTEEN: This is the End!
This week you need to take your final exam according to the instructions supplied by your
instructor. After you have studied as much as you can, have turned in what you need to turn in,
and have taken the final exam, you can breathe a sigh of relief and hopefully relax a little bit.
Upon reflection, we hope you have both enjoyed this course and have learned some neat
geology along the way. We are always looking for ways to improve our courses, especially in
the relatively new world of online, so any comments and suggestions you might have in this
regard would be more than appreciated.
ASSIGNMENTS FOR WEEK FIFTEEN
Textbook Reading: Review, Review, Review....
Lab Book Reading: Review, Review, Review....
Notes: You may wish to Review your previous notes....
Lab Assignment: Turn in any completed material that you are still allowed to!
Other Assignment: Make any last comments on the open Discussions/Forums. And, of
course, TAKE THE FINAL EXAM!
If in the future you are driving down a road somewhere, paddling down a river, or simply
walking in the woods, and you come across some geologic thing that causes you to go
"Hmmmmm, this reminds me of something we discussed in that geology course I took," then
from our end your experience in this course will have been worthwhile. We hope you have
many such "Hmmmmm" moments in your future!
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