Transcript What is Physical Geology?

Earth SC-202 Physical Geology
Instructor
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Prof. Steven Dutch
Office: LS 402
Phone: 465-2246
Email: [email protected]
Home Page: www.uwgb.edu/dutchs
Office Hours MWF 10:30-11:30, TR 9:30-10:50
What is Physical Geology?
Erosion
Soils
Weathering
Fossils
Wind
Water Oceans
Glaciers
Underground Surface
Sedimentary
Earth History
Rocks
Volcanoes
Metamorphic
Earth’s Interior
Igneous
Plate Tectonics
Earthquakes
Mountains
Mineral Resources
Other Planets
Intrusions
Syllabus
• Introduction to the course
• Minerals
• Igneous Rocks and
Volcanoes
• Weathering and Erosion
• Evolution of Landscapes
• Sedimentary Rocks
• Evolution, Fossils, Geologic
Time
• Glaciers
• Wind and Wave Erosion
• Metamorphism and
Deformation
• Earthquakes and Earth's
Interior
• Continental Drift and Plate
Tectonics
• Resources from the Earth
• Geology of other Worlds
Exams and Grading
Midterm I
Midterm II
Lab
Final
Field Trip
Attendance
50 points
50 points
100 points
80 points
20 points
10 points
Total
300 points
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AB
B
BC
C
CD
D
270+
255-269
240-254
225-239
210-224
205-210
200-204
Field Trip
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Dates
Mandatory – Absence Excuse Required
8:00 LS Parking Lot, Return 4:15
Casual Clothing – No strenuous hiking
Bring a lunch and fluids
Rest stops provided
Put on your calendar! No excuses!
Lab
• Instructor:
Jennifer Wessel
• Enroll in one
section
• 100 points total
Expectations
• Commitment
– Focus in class
• Professional Conduct
– No talking, texting
– Stay whole period
– Stay vertical and awake
• Use Syllabus
• Know your ID number or bring ID to exams
Sample exam question
• Which is the most desirable property in a
gemstone?
a.
b.
c.
d.
High hardness
Low hardness
Excellent cleavage
Density
Signs of Trouble
• Not making connections
– Lecture, lab, text, on-line, exams
• Not knowing your grade
• Not knowing what to study for
• Not knowing what’s on syllabus
Geology and Other Sciences
Physics
Chemistry
Biology
•Geophysics
•Mineralogy
•Paleontology
•Seismology
•Petrology
•Paleo????ology
•Geochemistry
Astronomy
Geology
•Historical Geology
•Planetary Geology
•Economic Geology •Geomorphology
•Helioseismology
•Hydrology
•Oceanography
•Engineering
Geology
•Structural Geology
•Volcanology
Who Geoscientists Are:
• About 30,000 in the U.S.
• Globally, in rich and poor countries, about one
per $50 million GNP.
• Mostly male but changing rapidly (now about
25% female in U.S.)
• Still less than 10% minority in U.S. (moving up
slowly)
Where Geologists Work
• 40 % Private Sector
• 30 % Academic
• 30 % Government
What Geologists Do:
• Locate Geologic Resources
• Geologic Hazard Mitigation
– Geological and Mining Engineering
– Site Study
– Land-Use Planning
• Environmental Protection
– Environmental Impact
– Ground Water and Waste Management
• Basic Research (Furnishes fundamental knowledge
for the applications)
Some Unique Aspects of Geology
Importance of Relationships
• Sequential
• Spatial
Importance of Time
Distinctive Problems of Evidence
• Slow Rates
• Rare Events
• Destruction of Evidence
• Inaccessibility
Some Geologic Rates
Cutting of Grand Canyon
• 2 km/3 m.y. = 1 cm/15 yr
Uplift of Alps
• 5 km/10 m.y. = 1 cm/20 yr.
Opening of Atlantic
• 5000 km/180 m.y. = 2.8 cm/yr.
Uplift of White Mtns. (N.H.) Granites
• 8 km/150 m.y. = 1 cm/190 yr.
Some Geologic Rates
Movement of San Andreas Fault
• 5 cm/yr = 7 m/140 yr.
Growth of Mt. St. Helens
• 3 km/30,000 yr = 10 cm/yr.
Deposition of Niagara Dolomite
• 100 m/ 1 m.y.? = 1 cm/100 yr.
1 Second = 1 Year
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35 minutes to birth of Christ
1 hour+ to pyramids
3 hours to retreat of glaciers from Wisconsin
12 days = 1 million years
2 years to extinction of dinosaurs
14 years to age of Niagara Escarpment
31 years = 1 billion years
Some Unique Aspects of Geology
(Continued)
Reliance on Inference and Deduction
Intrinsically "Unsolvable" Problems
• Ancient Landscapes
• Mass Extinctions
• Ancient Ocean Basins
Scientific Principles in Geology
• Parsimony (K.I.S.S.)
• Superposition
• Uniformitarianism
Using these, plus observation, we establish facts
about Earth Processes
Parsimony
• The simplest explanation that fits all the data
is preferred
• Doesn’t guarantee that things must be simple!
• Theories with lots of ad hoc or unsupported
ideas are probably wrong.
Parsimony: What is the best interpretation
of this well data?
Parsimony
• This?
• Or This?
Parsimony
• Rock layers
throughout NE
Wisconsin are
nearly flat and
little disturbed
• Glacial deposits
are always on top
of bedrock
• Therefore this is
the most likely
interpretation
One Implication of Parsimony
How do we know the laws of nature are the same
everywhere?
• Out to the farthest stars, everything seems to
obey the same laws of nature
• We find nothing in the rocks to suggest the laws
of nature were different in the past
Either:
• The laws of nature change but just happen to
produce effects that look like the presentlyknown laws of nature – or –
• The laws of nature really are the same
everywhere
Another Implication of Parsimony
• We live in a universe of patterns
• If someone claims there is an
exception to a known pattern, the
simplest explanation is that he/she is
wrong
• Therefore the burden of proof in
science is on the challenger
Superposition
Whodunit?
• Last night, one of Green Bay’s premier beer
can collections was stolen
• The only clue is footprints in the snow
• The thief was the last person to leave the
premises
The Suspects
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The Nephew
The Maid
The Cook
The Handyman
The Butler
Has a seeing-eye dog
Drives a car
Rides a motorcycle
Rides a bike
Walks to work
The Crime Scene
• The
Nephew has
a seeing-eye
dog
• The Maid
Drives a car
• The Cook
Rides a
motorcycle
• The
Handyman
Rides a bike
• The Butler
Walks to
work
Contacts
A Contact:
Mindoro Cut,
Wisconsin
Uniformitarianism
Continuity of Cause and Effect
• Apply Cause and Effect to Future - Prediction
• Apply Cause and Effect to Present Technology
• Apply Cause and Effect to Past Uniformitarianism
Uniformitarianism does not mean:
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Catastrophes never occur
Physical Conditions on Earth never Change
Earth has always been the same
Physical processes always occur at the
same rate or intensity
• Laws of Physics have always been the same
Uniformitarianism does mean:
Using our knowledge of physical laws, we can test:
• Whether catastrophes have occurred
• Whether physical conditions on earth have changed,
and if so, how (ice ages, warm periods, high or low
sea level, etc.)
• Whether physical laws themselves have changed in
time, or elsewhere in the universe.