What is Physical Geology?

Earth SC-202 Physical Geology

Instructor

• 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

Rocks

Igneous

Sedimentary

MetamorphicVolcanoes

Intrusions

Weathering

SoilsErosion

WaterUnderground Surface

Oceans

Wind

Glaciers

Fossils

Earth History

Earth’s InteriorEarthquakes

Mountains

Plate Tectonics

Other Planets

Mineral Resources

What is Physical Geology?

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 GradingMidterm I 50 pointsMidterm II 50 pointsLab 100 pointsFinal 80 pointsField Trip 20 pointsAttendance 10 points

Total 300 points

A 270+AB 255-269B 240-254BC 225-239C 210-224CD 205-210D 200-204

Field Trip

• 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. High hardnessb. Low hardnessc. Excellent cleavaged. 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 SciencesPhysics

•Geophysics

•Seismology

Chemistry

•Mineralogy

•Petrology

•Geochemistry

Biology

•Paleontology

•Paleo????ology

Astronomy

•Planetary Geology

•Helioseismology

Geology

•Economic Geology

•Hydrology

•Engineering Geology

•Historical Geology

•Geomorphology

•Oceanography

•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 GeologyImportance of Relationships• Sequential • Spatial Importance of TimeDistinctive Problems of Evidence• Slow Rates • Rare Events • Destruction of Evidence • Inaccessibility

Some Geologic RatesCutting of Grand Canyon• 2 km/3 m.y. = 1 cm/15 yrUplift 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 RatesMovement 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• 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 DeductionIntrinsically "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 ParsimonyHow 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 pastEither:• The laws of nature change but just happen to

produce effects that look like the presently-known 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

• 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

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:

• 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.