Volcanoes and Plutons

Process that forma Magma Increasing Temperature Decreasing Pressure Addition of Water

Environments of Magma Formation Spreading Center Mantle Plume Subduction Zone

Mantle Plume: Hot Spots Hawaii Island animation Iris Hot Spot

Subduction Zone

Basalt and Granite Asthenosphere is “PERIDOTITE” PERIDOTITE =“OLIVINE+PYROXENE+ Ca-Feldspar” Olivine 1,890°C, Pyroxene1,390°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