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