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Welcome
to GLG101C Introduction to Geology
Fall 2004
Professor James Tyburczy |
Department
of Geological Sciences |
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Chapter
4 Notes |
The Smithsonian Institution
has some great images
of rocks, minerals and meteorites on the web
Bob's
Rock Shop has images and information on rocks and minerals for rockhounds
and geology students
CHAPTER 4. ROCKS: RECORDS
OF GEOLOGIC PROCESSES
Rock types are defined
in terms of:
- Texture
- Mineralogy
- Chemical composition
Textures: - size, shape,
relationship of minerals
- fine-grained - less than
1 mm
- coarse-grained -
- mixed grain sizes
- glassy - when silicate
melts cool very very rapidly, crystals won't form
- vesicular (bubbles)
- fragmental - made up
of pieces of other rocks
- contains fossils or shells
Mineralogy
- Types of minerals
- Proportions of
each mineral
- Chemical composition
of the minerals
Igneous rocks - formed from
magma
- Intrusive versus extrusive
- what are the effects on texture?
- Most common minerals:
quartz, feldspars, mica, pyroxene, amphibole, olivine
- Temperatures - as low
as 700-800 deg C if water present, as high as 1100-1200 deg C if dry
- Plate Tectonic System
- Astheopshere and Lithosphere
Sedimentary rocks -
(uplift, that is, tectonics) - weathering & erosion - sediments - compaction
& cementation - lithification
- Interaction between the
Climate System and the Plate Tectonic System - Atmosphere and Hydrosphere
interact with Lithosphere
- Clastic versus chemical
(or biochemical) sedimentary rocks
- Most common minerals:
quartz, clays, feldspar, calcite
Metamorphic rocks -
change of mineralogy, texture, & chemical composition because of exposure
to heat and pressure.
- Contact metamorphism
versus regional metamorphism
- Most common minerals:
quartz, feldspar, mica, calcite
Rock Cycle
- Magma, Igneous
rocks, Sedimentary rocks, Metamorphic Rocks, Uplift, Weathering & Erosion,
Sediments
- Rock cycle in
context of plate tectonics - where do rocks of each type form?
- Rock cycle in terms of
Geosystems - Climate System and Plate Tectonic System - Atmosphere, Hydrosphere,
Lithosphere, Asthenosphere
©2004, James A. Tyburczy, Department of Geology, Arizona State University
If you have any questions or concerns regarding this page, please address
them to jfb@asu.edu.
Be specific in your description of the problem!
Last update 9/8/2004
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