Volcano NotesWhat materials erupt from Volcano?
1. Gases
2. Molten Rock
3. Solid Fragments
GASES
• STEAM is most abundant, 66%
• Other gases CO2, N, S, H, Cl, Ar, F
• White clouds: indicate STEAM
• Bluish/brown: indicate SULFUR
FUMAROLE
• Crack in a volcano• Temps range 200-
400 degrees• Alaska’s Valley of
10,000 Smokes• SOLFATARA:
special fumarole, releases SULFUR
Gases: determine eruption
• EXPLOSIVE: thick magma, trapped gases, Ex: Mt Pelee
• GENTLE: magma is fluid, gases can escape, Ex: Hawaii
Trapped gases underground
• HOT SPRINGS form when groundwater boils
• GEYSER is special type that erupts periodically
MOLTEN ROCK
• MAGMA: melted rock below the earth’s surface
• LAVA: melted rock above the earth’s surface
Types:
• AA: rough, jagged, sharp lava
• PAHOEHOE: smooth, satin-like, ropey lava
Examples:
• PILLOW LAVA: forms when lava flows into the ocean
• PILLAR LAVA: as lava cools, surface shrinks, forms hexagonal columns
SOLID FRAGMENTS• DUST: smallest• ASH: next largest• LAPILLI: grape-sized• CINDERS: glassy• BOMBS: tear-dropped• BLOCK: largest• TUFF: combination• PUMICE: light gray rock, floats• SCORIA: heavier, more red
Lapilli, Bomb, Pumice, Block
NUEE ARDENTE
• A mixture of steam, other gases, pumice, ash• Flows down hill like an avalanche
Sources of Magma• BATHOLITH: larger
than 40 square mi• STOCK: less than 40
square mi• LACCOLITH: Domed
surface• DIKE: vertical intrusion• SILL: horizontal
intrusion• PIPE: connects• NECK: center of cone• DOME: may form
FISSURE or RIFT
• Crack in the surface of earth
• Magma escapes• May be miles long
Top of Volcano:
• CONE: visible part of volcano, the rim is called the crater
• If rim collapses and enlarges it is called a CALDERA
