Plutonic and Plutonic and Volcanic ActivityVolcanic Activity

Plutonic and Plutonic and Volcanic ActivityVolcanic Activity

Intrusive Igneous Bodies

What are Plutons?

Concordant plutons

Laccoliths are _______________________.

Discordant plutons

Batholiths

Stocks

Volcanic pipes

What is Volcanism?

What are characteristics of the 3 Categories of Volcanoes?

Active volcanoes

Dormant volcanoes

Extinct volcanoes

Kilauea, Hawaii

What is a Crater?

What is a Caldera?

What are Volcanoes?

Crater Lake, Oregon

What is Viscosity?

What influences viscosity?

Magma Type

SilicaContent

ViscosityNa, K Al Ca, Fe, Mg

Mafic

Intermed.

Felsic

45 - 52%

53 - 65

> 65

low

medium

highIncrease

Increase

Composite Volcanoes (Stratovolcanoes)

Mt. St. Helens, WA

Characteristics of Lava Domes

(Mt. Lassen, CA = world’s largest)

Characteristics of Shield volcanoes

Characteristics of Cinder Cones

SP Crater, Arizona

What is Pahoehoe?

What is A'a?

What are Lava Tubes &

how do they form?

What is Pillow lava &

how does it form?

Lava solidifies, contracts, & fractures.

What is Columnar jointing?

OregonOregon

What are Pyroclastic sheets?

Marella River valley, Philippines

Characteristics of Pyroclastic material Ash =

Lapilli =

Bombs =

lapilli

ashbomb

________ of gas emitted is water vapor.

Lesser amounts of CO2, N, SO2, & H2SO4 are released.

Most gases quickly dissipate.

Volcanic GasesMt. Lassen, Calif.

What 4 things must you have to predict eruptions?

What are Volcanic tremors?

What do they indicate?

1. Swelling (magma moves into reservoir) 2. Shape change (increases in slope & distance b/w surface points)

3. Volcanic tremors are produced.4. Eruption occurs. 5. Volcano deflates & regains its original shape.

Where are volcanoes found?

Divergent Margins Convergent Margins Mafic magma forms oceanic crust Intermed. to Felsic magma Quiescent eruptions Explosive eruptions Shield volcanoes form along Composite volcanoes & lava

Mid-Ocean Ridges. domes comprise volcanic arcs

What is Intraplate Volcanism?What type of magma is associated with this type of volcanism?

Where are two locations of intraplate volcanism?