The science of Geology Geology is the science that pursues an understanding of planet Earth Physical...
-
Upload
christina-brown -
Category
Documents
-
view
220 -
download
1
Transcript of The science of Geology Geology is the science that pursues an understanding of planet Earth Physical...
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: [email protected] 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
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
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
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
• 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