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Clerical:
NOTE: Lecture Schedule revised to reflect reality.
Homework #3 is a relative age dating exercise. Please complete it by Friday (9/10/10).
Homework #4 is also posted. It is an exercise in absolute age dating, which will be the topic
of next Monday's lecture. I encourage you to complete it before Monday's class.
Quizzes 1 - 4 are posted.
Exam #1 will be given during class on Wednesday (9/15/10). The Exam #1 Study Guide is posted.
Themes of the Day:
- Geologic Processes and the Rock Cycle
- Principles of Relative Age Dating
- Interpreting Relative Ages in Geologic Cross-Sections
Geologic Processes and the Rock Cycle
- Geologic Materials
- Magma - molten rocks
- Igneous Rocks - crystallized from a magma
- Sediment - rock and mineral fragments produced by weathering
- Sedimentary Rocks - reconstituted from weathered rock fragments or chemicals - usually deposited by wind, water, or ice
- Metamorphic Rocks - pre-existing rock that has undergone changes in the solid state as a result of elevated pressure, temperature, or fluids
- Transitions within the Rock Cycle
- Magma cools and crystallizes (solidifies) to form igneous rocks - ex. Hawaiian lava
- Weathering is the physical or chemical breakdown of a rock (any type) and results in the formation of a sediment
- Physical sediments can be lithified by compaction and cementation into sedimentary rocks - chemical sediments can precipitate from solutions to form sedimentary rocks
- Igneous or sedimentary rocks can undergo metamorphism (solid state change) at high T or P or in the presence of fluids
- Metamorphic rocks may melt to form magmas under conditions of increasing T, decreasing P, or increased fluids
- Rock Origins in Relation to Driving Forces: Internal and External
Geologic Time Overview: Geologic Time Scale
- James Hutton - The Father of Modern Geology
- First to develop the notion of Deep Geologic Time, Uniformitarianism on a Geologic Time Scale
- Angular Unconformity at Siccar Point, Scotland - GE
- "... no vestige of a beginning, no prospect of an end ..."
- Relative vs. Absolute Methods of Age Dating
- Geologic Time Scale
Principles of Relative Age Dating
Interpreting Relative Ages in Geologic Cross-Sections
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