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EXTRUSIVE IGNEOUS
ROCKS
Volcanoes and Volcanic Rocks
What’s your favorite
volcano?
Famous Volcanoes
- Basalts
- Dotsero, CO
- Kilauea
- Mauna Loa
- Haleakala
- Hekla
- Andesites
- Fuji
- St. Helens
- Ranier
- Shasta
- Stromboli
- Vesuvius
- Popocatepetl
- Orizaba
- Pelée
- Rhyolites
- Yellowstone
- Valles
- Long Valley
- Crater Lake
- Pinatubo
- Krakatao
- Santorini
- Campi Phlegri (Naples)
Do you clean your
volcanoes regularly?
Where do volcanoes occur? Where do volcanoes occur?
• Plate Boundaries (98%)
- Divergent
- Ocean-ocean convergent
- Ocean-continent
Convergent
• Hot (wet) Spots
Where do volcanoes not
occur?
• Cratons
• Passive continental margins
• Oceanic abyssal plains
• Continent – continent
convergent boundaries
Most Volcanoes are at Plate Boundaries
Igneous Rock Names
and Compositions
• Intrusive
Rock Name
- Peridotite
- Gabbro
- Diorite
- Granite
• Composition
Name
- Ultramafic
- Mafic
- Intermediate
- Silicic (felsic)
• Volcanic
Rock Name
- (Komatiite)
- Basalt
- Andesite
- Rhyolite
Magma and Lava
- Magma is the term for any molten
silicate material, whether below
the surface or on top.
- Volcanic rocks are erupted on the
surface.
- Volcanic rocks are fine-grained (< mm)
- Lava is the term for a magma on
the surface.
Most Volcanoes are at Plate Boundaries
Geologic Settings
Cinder Cone + Caldera, (Basalt) Skjaldbreidur Shield, (Basalt)
Caldera, (Basalt) Halemaumau Basalt Flow Grand Canyon
< 1My old
Columnar Basalt Basaltic Eruptions
- Low Viscosity
- High Temperature (1000 - 1200ºC)
- Normally Quiescent Lava Flows
- Aa - early, low temperature, blocky flow
- Pahoehoe - later high temperature ropy flow
- Pillow Lavas - underwater flow
- Edifice
Famous Volcanoes
- Basalts
- Dotsero, CO
- Kilauea
- Mauna Loa
- Haleakala
- Hekla
- Vulcan’s Throne - Andesites - Fuji - St. Helens - Ranier - Shasta - Stromboli - Vesuvius - Popocatepetl - Orizaba - Pelée - Etna - Rhyolites - Yellowstone - Valles/Jemez - Long Valley - Crater Lake - Pinatubo - Krakatao - Santorini - Campi Phlegri (Naples)
Most Volcanoes are at Plate Boundaries
Andesite Eruptions
- Higher viscosity ( higher polymerization)
- Lower temperature
- More water, more explosive
- Subduction zone volcanism
- Flows
- Viscous lava flows
- Pyroclastic flows
- Edifice
Geologic Settings
Which volcanic environment will, on average, produce the most felsic (silicic) lavas? A. Mid-ocean ridge B. Island arc C. Continental arc D. Oceanic hotspot
Clicker Question
Plate tectonics explains the
global pattern of volcanism.
Which volcanic environment will, on average, produce the most felsic (silicic) lavas? A. Mid-ocean ridge B. Island arc C. Continental arc D. Oceanic hotspot
Clicker Question
Plate tectonics explains the
global pattern of volcanism.
Ash Flow Eruption,
Llaima Volcano, Chile
Composite Cone, Mt. St Helens
Andesite Eruptions
- Higher viscosity ( higher polymerization)
- Lower temperature
- More water, more explosive
- Subduction zone volcanism
- Flows
- Viscous lava flows
- Pyroclastic flows (Nuée Ardente)
- Edifice
Famous Volcanoes
- Basalts
- Dotsero, CO
- Kilauea
- Mauna Loa
- Haleakala
- Hekla
- Vulcan’s Throne - Andesites - Fuji - St. Helens - Ranier - Shasta - Stromboli - Vesuvius - Popocatepetl - Orizaba - Pelée - Etna - Rhyolites - Yellowstone - Valles/Jemez - Long Valley - Crater Lake - Pinatubo - Krakatao - Santorini - Campi Phlegri (Naples)
Clicker Question
- Which of the following is an
example of a basalt volcano?
- A. Mt St. Helens
- B. Yellowstone
- C. Mauna Loa
- D. Mt Pinatubo
- E. Mt. Fuji
Clicker Question
- Which of the following is an
example of a basalt volcano?
- A. Mt St. Helens
- B. Yellowstone
– C. Mauna Loa
- D. Mt Pinatubo
- E. Mt. Fuji
Clicker Question
- Which of the following is an
example of an andesite volcano?
- A. Kilauea
- B. Yellowstone
- C. Mauna Loa
- D. Mt Pinatubo
- E. Mt. Fuji
Ash-Flow Tuff Unit Ash-Flow Tuff Unit
Non-Welded Top
Welded Core
Vitrophyre
Non-welded base
Silicic Tuff Units (Jemez, NM)
Obsidian Flow
Non-welded
Air-Fall Units
Sulfur Fumarole, Nysseros
Caldera with Cinder Cone
Crater Lake, OR
Geyser
Old Faithful
(Yellowstone)
Rhyolite Eruptions
- Very high viscosity
- Low temperature (600 - 800ºC)
- Massive Pyroclastic eruptions
- Air fall (pumice)
- Ash Flow (Nuée Ardente) Tuff
- Obsidian Flows
- Edifice
- Caldera (5 - 25 km)
- Resurgent dome
Andesite Eruptions
- Higher viscosity ( higher polymerization)
- Lower temperature
- More water, more explosive
- Subduction zone volcanism
- Flows
- Viscous lava flows
- Pyroclastic flows
- Edifice
Basaltic Eruptions
- Low Viscosity
- High Temperature (1000 - 1200ºC)
- Normally Quiescent Lava Flows
- Aa - early, low temperature, blocky flow
- Pahoehoe - later high temperature ropy flow
- Pillow Lavas - underwater flow
- Edifice
Crater Lake, OR
A.Basalt
B.Andesite
C.Rhyolite
Crater Lake, OR
A.Basalt
B.Andesite
C.Rhyolite
Famous Volcanoes
- Basalts
- Dotsero, CO
- Kilauea
- Mauna Loa
- Haleakala
- Hekla
- Andesites
- Fuji
- St. Helens
- Ranier
- Shasta
- Stromboli
- Vesuvius
- Popocatepetl
- Orizaba
- Pelée
- Rhyolites
- Yellowstone
- Valles/Jemez
- Long Valley
- Crater Lake
- Pinatubo
- Krakatao
- Santorini
- Campi Phlegri (Naples)
Volcanic Terms
- Ultramafic
- Mafic
- Intermediate
- Silicic
- Basalt
- Andesite
- Magma
- Lava
- Aa
- Pahoehoe
- Pillow Lava
- Shield
- Composite Cone
- Cinder Cone
- Caldera
- Pyroclastic
- Nuée Ardente
- Air Fall
- Ash Flow
- Tuff
- Obsidian
- Vitrophyre
- Pumice
- Resurgent dome
- Hot Spring
- Geyser
- Rhyolite
EXTRUSIVE IGNEOUS
ROCKS
Volcanoes and Volcanic Rocks
Igneous Rock Names
and Compositions
• Intrusive
Rock Name
- Peridotite
- Gabbro
- Diorite
- Granite
• Composition
Name
- Ultramafic
- Mafic
- Intermediate
- Silicic (felsic)
• Volcanic
Rock Name
- (Komatiite)
- Basalt
- Andesite
- Rhyolite
Most Volcanoes are at Plate Boundaries
Famous Volcanoes
- Basalts
- Dotsero, CO
- Kilauea
- Mauna Loa
- Haleakala
- Hekla
- Vulcan’s Throne - Andesites - Fuji - St. Helens - Ranier - Shasta - Stromboli - Vesuvius - Popocatepetl - Orizaba - Pelée - Rhyolites - Yellowstone - Valles - Long Valley - Crater Lake - Pinatubo - Krakatao - Santorini - Campi Phlegri (Naples)
Volcanic Terms
- Ultramafic
- Mafic
- Intermediate
- Silicic
- Basalt
- Andesite
- Magma
- Lava
- Aa
- Pahoehoe
- Pillow Lava
- Shield
- Composite Cone
- Cinder Cone
- Caldera
- Pyroclastic
- Nuée Ardente
- Air Fall
- Ash Flow
- Tuff
- Obsidian
- Vitrophyre
- Pumice
- Resurgent dome
- Hot Spring
- Geyser
- Rhyolite
Clicker Not Registered
Clicker Not Registered
- McClelland, A • Keegan, R.
- Moten, J.
- Runyon, K.
- Scott, G.
- Shepley, J.
- Wheeler, S.
Clicker Not Registered
- McClelland, A • Keegan, R.
- Moten, J.
- Runyon, K.
- Scott, G.
- Shepley, J.
- Wheeler, S.
