What is physical geology

Earth SC-202 Physical Geology... • Earthquakes and Earth's Interior• Continental Drift and Plate Tectonics • Resources from the Earth • Geology of other Worlds... Some Unique Aspects of

Earth SC-202 Physical Geology

• Earthquakes and Earth's Interior

• Continental Drift and Plate Tectonics

• Resources from the Earth

• Geology of other Worlds

Exams and Grading

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!

– 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 hardness

b Low hardness

c Excellent cleavage

d 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

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

Some Geologic Rates

Cutting of Grand Canyon

Some Geologic RatesMovement of San Andreas Fault

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 Deduction

Intrinsically "Unsolvable" Problems

• Ancient Landscapes

• Mass Extinctions

• Ancient Ocean Basins

Scientific Principles in Geology

• 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?

• This?

• Or This?

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

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

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 Cook Rides a motorcycle

• The Handyman Rides a bike

• The Butler Walks to work

The Crime Scene

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.