Concurrent G204 Geology Lab is required Schedule: Reading Week 1: Introduction to Geology

Intrd. to Oregon Geology........................................................Chapter 1 Week 2: Plate Tectonics……………………………................................Chapter 2 Quiz 1: Week 3 (January 23rd) Week 3: Minerals; mineral groups & systematics................................Chapter 3 Week 4: Weathering and Soil (Guest lecturer – Prof. Scott Burns)....Chapter 6 Week 5: Igneous Rocks............................................................................Chapter 4 . Mid-term exam 1: Week 6 (February 13th) Week 6: Volcanoes and igneous activity...............................................Chapter 5 Week 7: Sedimentary rocks....................................................................Chapter 7 Week 8: Metamorphism & meta. rocks, crustal deformation……..Chapters 8, 10

Mid-term exam 2: Week 9 (March 6th) Week 9: Crustal deformation, Geological time.....................................Chapter 9 Week 10: Earthquakes, Earth interior, Summary of Class............Chapters 11, 12

Final exam: March 20th, 19:30-21;20 Text: Earth, An Introduction to Physical Geology; Tarbuck & Lutgens, Prentice Hall, 8th edition (also used in G202) – custom edition for Portland State University.

G201 General Geology, Winter Term 2007

instructor: Martin J. Streck office: Geol 17H phone: 725-3379 email: streckm@pdx.edu Dept. of Geology office hours: T 1 - 2 pm

Lecture: T, 18:40-21:20, PCAT 160

Exams: All will be multiple-choice exams; the Final exam will include few additional questions to be answered separately. Readings: See above, some selection for Week 8, 9, 10 reading will be announced in class. Grade Allocation: Quiz in week 3, 10% Mid-term exams @ 25 % each 50% Final written exam 40% Grading Policy: 93-100 A 90-92 A– 87-89 B+ 83-86 B 80-82 B– 77-79 C+ 73-76 C 70-72 C– 67-69 D+ 63-66 D 60-62 D– < 60 F

The science of Geology

Geology is the science that pursues an understanding of planet Earth

• Physical geology - examines the materials composing Earth and the processes generating them

• Historical geology - seeks an understanding of the origin of Earth and its development through time; chronology of events

Geologic timeAccurate dates to events in Earth history

• Absolute dating

Relative dating and the geologic time scale • Relative dating means that dates are placed in their proper

sequence or order without knowing their age in years

The magnitude of geologic time • Involves – millions or billions of years • Geological processes operate

– Gradually over periods as much as millions of years – Episodic in events that may last only seconds to minutes

Geologic timescale

Age

in m

illi

ons

of y

ears

Early evolution of Earth

Origin of planet Earth

• Earth and the other planets formed at the ~same time from interstellar dust

• Nebular hypothesis

Layered structure developed by chemical segregation early in the formation of Earth

A view of Earth

Earth’s four spheres • Hydrosphere• Atmosphere• Biosphere• Solid Earth

Earth as a machineInternal forces

Powered by heat from the interior

• Leads to convection in the earth

• Moves plates on the earth surface

• Produce volcanoes, earthquakes, and mountains

External forces - Powered by the Sun that drives external processes in the

• Atmosphere

• Hydrosphere

• At Earth’s surface

Earth’s surface has two principal divisions

• Continents

•Ocean basin

The workings behind the scene Surface features, like oceans, mountains and others, are the product of internal workings of the earth

Earth’s internal structure

“Layercake” Earth• Crust

• continental• oceanic

• Mantle• upper• lower

• Core• outer• inner

Mechanical Subdivision of the upper Earth• Lithosphere

(rigid)• Asthenosphere

(ductile, plastic)• Mesosphere

Earth’s internal structure

Earth’s Surface

Earth’s crust broken into rigid plates

7 major plates

Where plates meet are called plate boundaries

Three types of plate boundaries

Plate Boundaries

Divergent (constructive) boundary – plates move apart, resulting in upwelling of material from the mantle to create crust

Convergent (destructive) boundary – plates move towards each other; subduction of oceanic plates or collision of two continental plates

Transform (conservative) boundary – plates move along each other without either generating new lithosphere or consuming old lithosphere

Dynamic EarthThe theory of plate tectonics

• Theory, called plate tectonics, has now emerged that provides geologists with the first comprehensive model of Earth’s internal workings

The theory of plate tectonics• Involves understanding the workings of our

dynamic planet

• Began in the early part of the twentieth century with a proposal called continental drift – the idea that continents moved about the face of the planet

The loop that involves the processes by which one rock changes to another

Illustrates the various processes and paths as earth materials change both on the surface and inside the Earth

The Rock Cycle

There are three rock classes

Igneous (magmatic) rocksSedimentary rocksMetamorphic rocks

• formed from a magma through crystallization either at or beneath the surface• examples: lava flows, granite, basalt, pumice

Melting

Magma

Cooling + Crystallization

Igneous rocks

Lava

Igneous Rocks

Sedimentary Rocks

• formed through deposition of solid particles or through precipitation• examples: sandstone, claystone, limestone

Deposition or PrecipitationCementation + Compaction(Lithification)

Sedimentary rocks

Sediment

Transport

Metamorphic Rocks

• formed through metamorphic transformation due to heat and pressure• examples: schist, slate, marble

Heat + Pressure(Metamorphism)

Metamorphic rocks

Compression

Heat

The science of Geology

Some historical notes about geology • The nature of Earth has been a focus of study

for centuries • Catastrophism – earth changes by large events

like floods, eruptions, etc. • Uniformitarianism – present is key to past;

processes same through time, only rates have changed

The nature of scientific inquiry

Science assumes the natural world is consistent and predictable

Goal of science is to discover patterns in nature and use the knowledge to make predictions

Scientists collect “facts” through observation and measurements

The nature of scientific inquiry

How or why things happen are explained using a

• Hypothesis – a tentative (or untested) explanation

• Theory – a well-tested and widely accepted view that the scientific community agrees best explains certain observable facts

The nature of scientific inquiry

Scientific methods • Scientific method involves gathering facts

through observations and formulation of hypotheses and theories

There is no fixed path that scientists follow that leads to scientific knowledge