Volcanoes and Plutons

Volcanoes and Plutons

Process that forma Magma

• Increasing Temperature• Decreasing Pressure• Addition of Water

Environments of Magma Formation

• Spreading Center• Mantle Plume• Subduction Zone

Hawaii Island animation

Iris Hot Spot

Mantle Plume: Hot Spots

Subduction Zone

Basalt and Granite• Asthenosphere is “PERIDOTITE”• PERIDOTITE =“OLIVINE+PYROXENE+ Ca-Feldspar”

Olivine 1,890°C, Pyroxene1,390°C, Calcium Feldspar 1,550°C

Peridotite 1,270°C the product of the first melt Rich In Silica Partial Melting: A small amount of original peridotite melts to form basaltic magma

Plutons• When a large granitic magma solidifies with in

Earth’s crust to form a large mass of Granite called a pluton

Types of Lava • Pahoehoe Low Viscosity, as it cools stiffens

forming smooth, glassy surfaced, wrinkled or ropy ridges

• Aa higher viscosity surface partially solidify as it flows

• Pillow lavas is a lava structure that typically when lava is emerged from an underwater volcanic vent.

• Pyroclastic rock rock fragments• Volcanic Ash

Volcanoes• When lava is too viscous to spread out as a

flood it builds a hill or mountain call Volcano

Shield Volcanoes• Basaltic Magma • Gentle sloping mountain• at angles 6° to 12°

Cinder Cones • Small volcano composed of Pyroclastic fragments• Large amount of gas accumulates in rising magma

Composite Volcanoes• Stratovolcano • form by longs periods of time by alternating lava flows and pyroclastic

material

Calderas

Volcanic Eruptions and Global Climate