Transcript The Rock Cycle

The Rock Cycle
The processes through which
rocks are formed
Igneous Rocks
 Form by the cooling of molten rock (either
lava or magma)
 Typically have a texture of random crystals
Iceland - 1980s, Alan Rubin
Eruption of Mount St. Helens - May, 1980 (commercial slide)
Mount St. Helens - 2004
Middle and North Sister - Oregon Cascades
Sedimentary Rocks
 Often form when particles weathered from
earlier rocks are transported (by streams,
wind or glaciers) and deposited as sediment
 The sediment is then buried and converted
to rock by compression and cementation
 Typically have a texture of small rounded
particles cemented together
French Pete Creek - Oregon Cascades
Basin and Range - eastern Nevada
Cochetopa Creek near Gunnison, Colorado
Creek building delta into Lyman Lake - Washington Cascades
Cape Cod, Massachusetts
Canyonlands National Park, UT - Needles section
Metamorphic Rocks
 Generally form when earlier rocks are
subjected to high temperatures and/or
pressures (BUT without melting!)
 Typically have a crystalline texture, with a
pattern to the arrangement of crystals
Mt. Jefferson,
Oregon Cascades
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