Geography 201

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Geography 201

• Rocks, Minerals and Landforms

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Major Concepts

• Geologic time scale
• Rocks and minerals
• Origins of lithosphere
• Rock cycle

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1,000,000
1,000,000,000
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The lithosphere crust mantle core
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The Rock Cycle
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Major Concepts Igneous Rocks

• Fire-formed
• Extrusive small crystals, smooth
• Intrusive large crystals, coarse
• Mafic dark, massive
• Felsic light, less massive

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Pyroclastic flow
Rope lava
Extrusive Igneous - mafic
Geography 379 - camping Craters of the Moon, Idaho
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Extrusive Igneous - felsic
Northwestern area, Yellowstone National Park,
Wyoming
USGS marker in igneous rock, near Cody, Wyoming
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Basaltic flows
Columbia River, Oregon
Near Idaho Falls, Idaho
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Batholithic Intrusions
Coquihalla Highway, B.C.
Grand Tetons, Wyoming
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Yosemite Falls, California
Black Hills, South Dakota
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An interesting igneous formation, South Dakota.
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Major Concepts Sedimentary Rocks

• Deposition and lithification
• basins
• Clastic parent rock inorganic
• Non-clastic parent rock organic

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Dinosaur Provincial Park
Near Oyen, Alberta
Strata and bedding planes
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The Grand Canyon
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Near Banff, Alberta
Colorado River, Arizona
Horizontal bedding
Red Rock Canyon, Utah
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Great Sand Dunes, Colorado
Snake River, Wyoming
Parent Materials
Coastal California
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Front Range of the Rocky Mountains
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Bryce Canyon
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Major Concepts Metamorphic Rocks

• Magmatic intrusion
• Intense heat and pressures

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Pressure heat Metamorphic rock
Gneiss
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Major Concepts Vulcanism

• Magma chamber
• Intense heat and pressures below surface
• Extrusive igneous rock
• Shield volcanos mafic, flowing lavas
• Classical or composite cones felsic, thick,
  viscous lavas

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Yellowstone Geyser
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Lavas, gases, Pyroclastic Materials (ash)
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Two major types of volcanos exist one, the
shield are made of mafic rock lavas are thin
and travelling, there are few gases and
volcanic events tend to not be
explosive. Composite (stratovolcanos) Are
composed of felsic rock. These are lighter in
colour And mass and tend to form thick, viscous
lavas, These Volcanos are often explosive In
nature and cause nuee ardente and lahars.
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Thin, running lavas are associated with mafic
lavas and shield volcanos
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May different types of volcanic bombs, ash and
pumice of all shapes and sizes are emitted from
volcanos of all types.
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Mt. St. Helens, May 1980. A felsic volcano,
dormant for Hundreds of years, explodes and
spews Ash and gas 20 km into the air. Ash and
gas fell through western North America as far
east as Winnipeg.
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Mt. St. Helens, Washington
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Caldera form at the top of volcanos, formed by
subsidence following a volcanic event
misnamed Craters, they often fill with Water ---
like Crater Lake, Oregon and Wizard Island.
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Caldera, after long periods of time ---as here in
Northern new Mexico --- can be difficult to
identify
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The Menan Buttes, Idaho Display the westward
movement of the North American plate. Two conder
cones where the magma from deep below the
surface has found its way to the earths surface
through a hotspot.
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More evidence of the movement of the North
American plate. Photo by Jo Lusty, 2002
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Students from Geography 379 explore lave beds
basaltic flows In southern Idaho (June 2002)
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Remnants of past volcanic activity reamain on
the landscape --- these rocks are significantly
harder than the surrounding sedimentary
materials
Pocacatapytl, Mexico And Ship Rock, New Mexico
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The Monument Valley Utah - Arizona
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Giants Causeway, Ireland
Devils Tower. Wyoming
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Pinyon Sunsert, Navajo Reservation, Arizona,
U.S.A.