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Lecture Outlines Physical Geology, 14/e Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Plummer, Carlson & Hammersley
Volcanism and Extrusive Rocks Physical Geology 14/e, Chapter 4 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Atmosphere – originally created from gases released from volcanic eruption Hydrosphere – produced by condensation of volcanic water vapor Biosphere both positively and negatively influenced by volcanism lava flows and ash weather to produce fertile soils violent eruptions can destroy nearly all life in their paths large amounts of ash and volcanic gases in atmosphere can trigger rapid climate changes and contribute to mass extinctions Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Volcanism & earth’s systems
Lava – produced when magma reaches Earth’s surface explosive eruptions can produce rapidly cooled rock fragments called pyroclasts, size ranges from dust (ash) to boulders (blocks and volcanic bombs) calm oozing of magma out of the ground produces lava flows pyroclastics and lava flows form extrusive igneous rocks lava flows and pyroclasts pile up to form volcanoes Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Volcanic eruptions
Mythology, religion and volcanoes Hawaii – Pele, Iceland – Loki Growth of volcanic islands (Hawaii) Geothermal energy natural steam harnessed as clean energy resource Climatic effects very large eruptions can result in measurable global cooling resulting crop failures and famines Volcanic catastrophes Mt. St. Helens, Pompeii, Krakatoa, Tambora, Crater Lake Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Living with volcanoes
Violence of eruptions controlled by: dissolved gases in the magma ease/difficulty of gases escaping to atmosphere Viscosity - a fluid’s resistance to flow higher silica contents produce higher viscosities cooler lavas have higher viscosities amount of dissolved gases, the more dissolved gases, the more fluid the lava Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Eruptive violence & physical characteristics of lava
Scientific Investigation of Volcanism rocks, gases and events from observed eruptions compared to similar lavas elsewhere to infer the nature of past activity Rock Composition lightrhyolite - high silica; light color darkbasalt - low silica; dark color andesite - intermediate silica and color Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Extrusive rocks and gases
Vent - opening through which lava erupts Crater - basin-like depression over the vent at the summit of the volcano Caldera - volcanic depression much larger than the original crater, having a diameter of at least 1 km Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Volcanic landforms
Shield volcanoes broad gently sloping composed of solidified lava flows flows often contain lava tubes Cinder cones small steeply sloping composed of a pile of loose cinders Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Types of volcanoes
Composite volcanoes aka stratovolcanoes moderately to steeply sloping constructed of alternating layers of pyroclastic debris and solidified lava flows composed primarily of intermediate composition volcanic rocks (i.e., andesite) most common type of volcano at convergent plate boundaries Volcanic domes extremely high viscosity, degassed, felsic lavas (often glassy, e.g., obsidian) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Types of volcanoes
Flood eruptions very fluid (basalts) extremely large in volume create extensive lava plateaus eruption times correspond with largest mass extinction events Submarine eruptions nearly always basaltic mid-ocean ridge eruptions pillow basalts Columbia river flood basalts Pillow basalts Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Other eruption types
Shield volcanoes Venus, Mars, Io Lava domes Venus, Moon Flood eruptions very fluid (basalts) extremely large in volume extensive flat lava plains (Moon, Mars, Venus, Mercury?) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Volcanism on other planets
End of Chapter 4 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Types of Volcanoes Chapter 11 Section 2. Types of Eruptions: Quiet Explosive Determined by: –Amount of water vapor/trapped gases in the magma. –Amount.
Ch. 18 Volcanoes. Ch. 18 Vocabulary Viscosity Tepha Vent Hot Spot Caldera Cinder-Cone Volcano Composite Volcano Pyroclastic Flow Shield Volcano Crater.
Volcanoes What is a volcano? A volcano is a mountain that forms when molten rock erupts or flows as lava from an opening in Earth’s surface.
Volcanoes Eruptions and Forms of Volcanoes. Types of Eruptions Violent and explosive Quiet and flowing –Depends on trapped gases and magma composition.
Volcano Hw and RQ. Questions Could Mt. St. Helens erupt again? Does the lava come from the liquid core of the Earth? Is every mountain a volcano? How.
Volcanoes and their effects on Earth EQ: How do volcanoes effect Earth’s surface?
Lets Review… Copy in Notebook and Answer: –Compare and contrast magma and lava. –What plate boundaries will result in formation of a volcano?
Open your binder to the notes section. Prepare to take notes. Head your notes and copy the standard below. Open your binder to the notes section. Prepare.
1 Volcanoes Exploding mountains?. 2 VOLCANOES The word "volcano" comes from the little island of Vulcano in the Mediterranean Sea off Sicily (Italy).
Composite Volcanoes Review: What characteristics make a composite volcano? Answer: High Gas, High Silica, High Viscosity.
Our Dynamic Earth. Earth as a System The Earth is an integrated system that consists of rock, air, water, and living things that all interact with each.
PH307 Disasters: Volcanos Dr. Dirk Froebrich This presentation can be found at:
Earthquakes, Volcanoes, and Tsunamis. Earthquakes Fault: a break in the Earths crust. Blocks of the crust slide past each other along fault lines. When.
Volcanic Landforms. Landforms From Lava and Ash Rock and other materials formed from lava create a variety of landforms including shield volcanoes,
CST Review Standard 3 Plate Tectonics operating over geologic time has changed the patterns of land, sea, and mountains on Earths surface. a.Know the features.
Tungerahua Volcano, Ecuador Picture by Alcinoe Calahorrano Volcanoes.
Volcanoes Chapter 7. Volcanoes of the World Relationships of Volcanic Activity to Plate Tectonics.
Volcanism Volcanic Features Location and Types of Volcanic Activity Effusive Eruptions Explosive Eruptions Volcano Forecasting and Planning.
Birth of a Theory Continental Drift and Plate Tectonics.
1 Volcanoes Exploding mountains? EVERYONE But before that – a bit of revision from last week and I want EVERYONE to have a go!
Impact of eruptions V o l c a n o e s Prediction Part II Supervolcanoes.
The Parts of a Volcano. What is a Volcano? A volcano is a mountain that forms when magma reaches the surface of the Earth. Magma rises because it is less.
Volcanoes By Seth Linford, 3/11/10. Shield Volcano Shield volcanoes are seen as a gentle, sloping mountain. Most examples are in the ocean, such as the.
Chapter 11 Earthquakes and Volcanoes. Earthquakes l The shaking caused by the sudden movement of the crust l Scientists estimate that over one million.
U-shaped Valley Valley V-shaped Valley Valley Cave Atoll.
Chapter 12 Section 1. What is a Volcano? Opening in the Earth (called a vent) that erupts gases, ash, and lava. –Volcanic mountains result from the build-up.
Rocks Chapter 4. What is a rock? Rock Mixture of minerals, rock fragments, volcanic glass, organic material, or other natural materials.
A volcano is an opening in the Earth’s crust where lava comes out.
Volcanoes Carly Irving and Laura Cryan. What causes a volcano? Deep within the Earth it is so hot that some rocks slowly melt and become a thick flowing.
Volcanic Activity. How Magma Reaches the Surface Magma rises because magma is less __________ than the surrounding _________ material. Magma rises because.
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