Presentation is loading. Please wait.

Presentation is loading. Please wait.

Volcanism and Extrusive Rocks Physical Geology 12/e, Chapter 4

Published byStuart Jenkins Modified over 6 years ago

Similar presentations

Presentation on theme: "Volcanism and Extrusive Rocks Physical Geology 12/e, Chapter 4"— Presentation transcript:

1 Volcanism and Extrusive Rocks Physical Geology 12/e, Chapter 4

2 Eruptive Violence and Physical Characteristics of Lava
Violence of eruptions controlled by: Dissolved gases in the magma Water vapor, carbon dioxide, sulfur dioxide, etc. Ease/difficulty of gases escaping to atmosphere Viscosity- a fluid’s resistance to flow Silica content Higher silica contents produce higher viscosities Lava temperature Cooler lavas have higher viscosities Amount of dissolved gases The more dissolved gases, the more fluid the lava Violence and Viscosity are interconnected.

3 Volcanism and Earth’s Systems
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 Review - previously read this in the book.

4 Volcanic Eruptions Lava is produced when magma reaches Earth’s surface
Explosive eruptions can produce rapidly cooled rock fragments called pyroclasts Size range 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 Review - previously read this in the book.

5 Living with Volcanoes 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 Notes ch 4 - write the underlined info

6 Eruptive Violence and Physical Characteristics of Lava cont. page 90-91
Igneous Family Silica Content Viscosity Violence of Eruption Silicic (Felsic) Fill in the chart.

7 Eruptive Violence and Physical Characteristics of Lava cont. page 90-91
Igneous Family Silica Content Viscosity & Flow Violence of Eruption Silicic (Felsic) 65% (Silica Rich) High & Sluggish Violent Intermediate 35-50% Medium Mafic Less than 50% Deficient Low & Easily Minimal More flows Fill in the chart and go over.

8 Extrusive Rocks and Gases
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 Rhyolite - high silica; light color Basalt - low silica; dark color Andesite - intermediate silica and color Review

9 Extrusive Textures Texture - appearance of a rock with respect to size, shape and arrangement of its grains Glassy - glass without mineral crystals Obsidian Fine-grained - most crystals < 1 mm e.g., Basalt Porphyritic - larger crystals in a matrix of much finer crystals (groundmass) or glass e.g., Andesite Review

10 Extrusive Textures Vesicular/Frothy - trapped gas bubbles
Vesicular basalt Pumice Fragmental - particles blasted apart by explosive eruptions Dust and ash (<2 mm) Cinders (2-64 mm) Blocks and bombs (>64 mm) Review

11 Volcanic Landforms 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 Copy into notes.

12 Volcano Target Notes Definition Lifespan & Eruptive Material
Type of Volcano Meaningful Sentence Diagram

13 Types of Volcanoes pages 96-103
Diagram Define & any charac. Lifespan Eruptive Material Rock Type Shield Composite (Stratovolcano) Cinder Dome Copy chart and fill in using the book

14 What am I???

15 Types of Volcanoes Shield volcanoes Cinder cones 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

16 Types of Volcanoes Composite volcanoes Volcanic domes
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 (e.g., Pacific Ring of Fire) Volcanic domes Extremely high viscosity, degassed, felsic lavas (often glassy, e.g., obsidian)

17 Other Eruption Types Flood eruptions Submarine 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

18 Volcanism on Other Planets
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?) Insert Fig here Insert Fig A here Olympus Mons on Mars Volcanic eruption on Io Insert Fig A here Lava domes on Venus Lava channel in volcanic plains on Moon

19 End of Chapter 4

Download ppt "Volcanism and Extrusive Rocks Physical Geology 12/e, Chapter 4"

Similar presentations

Types of Volcanoes Chapter 11 Section 2.

Types of Volcanoes Chapter 11 Section 2.
Volcanism and Extrusive Rocks

Volcanism and Extrusive Rocks
Lecture Outlines Physical Geology, 14/e Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Plummer, Carlson &

Lecture Outlines Physical Geology, 14/e Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Plummer, Carlson &
Chapter 5 Volcanoes and Volcanic Hazards. The Nature of Volcanic Eruptions  Factors determining the “violence” or explosiveness of a volcanic eruption:

Chapter 5 Volcanoes and Volcanic Hazards. The Nature of Volcanic Eruptions  Factors determining the “violence” or explosiveness of a volcanic eruption:
Making Connections with New Stuff 1. 3 types of volcanoes 2. Volcanoes and the formation of Early Earth 3. Minerals, Rocks, and the Rock Cycle 4. Divergent.

Making Connections with New Stuff 1. 3 types of volcanoes 2. Volcanoes and the formation of Early Earth 3. Minerals, Rocks, and the Rock Cycle 4. Divergent.
Today: Chapter 6 Volcanism

Today: Chapter 6 Volcanism
THE LANGUAGE OF THE EARTH – PART I IGNEOUS ROCKS.

THE LANGUAGE OF THE EARTH – PART I IGNEOUS ROCKS.
Igneous Rocks. Rock Cycle Types of rocks Area of exposure on surface and volume fraction.

Igneous Rocks. Rock Cycle Types of rocks Area of exposure on surface and volume fraction.
Chapter 4 Volcanism and Extrusive Rocks IndexIndex  

Chapter 4 Volcanism and Extrusive Rocks IndexIndex  
Chapter 7 Section 2 Volcanic Eruptions.

Chapter 7 Section 2 Volcanic Eruptions.
Volcanoes. 7.1 Volcanoes and Plate Tectonics Magma – hot liquid rock Volcanism – movement of magma toward suface Lava – magma on the surface Vent.

Volcanoes. 7.1 Volcanoes and Plate Tectonics Magma – hot liquid rock Volcanism – movement of magma toward suface Lava – magma on the surface Vent.
Volcanoes Geology 12 Citadel High School. What comes out of a volcano? Gas Most common: H 2 O - water CO 2 – Carbon Dioxide SO 2 – Sulfur Dioxide HCl.

Volcanoes Geology 12 Citadel High School. What comes out of a volcano? Gas Most common: H 2 O - water CO 2 – Carbon Dioxide SO 2 – Sulfur Dioxide HCl.
VOLCANOES. What is a Volcano? A volcano is a weak spot in the crust where Magma, comes to the surface. Volcanic activity is a constructive force that.

VOLCANOES. What is a Volcano? A volcano is a weak spot in the crust where Magma, comes to the surface. Volcanic activity is a constructive force that.
Chapter 7: Volcanoes. New Vocabulary Lava- magma (or hot, liquid rock) that reaches the surface Pyroclasts- hot rock fragments (from the Greek word “pyro”

Chapter 7: Volcanoes. New Vocabulary Lava- magma (or hot, liquid rock) that reaches the surface Pyroclasts- hot rock fragments (from the Greek word “pyro”
Volcanism and Extrusive Rocks. Volcanism and Earth’s Systems Atmosphere originally created from gases released by magmas Hydrosphere produced by condensation.

Volcanism and Extrusive Rocks. Volcanism and Earth’s Systems Atmosphere originally created from gases released by magmas Hydrosphere produced by condensation.
Tim Horner CSUS Geology Department Volcanism and Extrusive Rocks Physical Geology 13/e, Chapter 4.

Tim Horner CSUS Geology Department Volcanism and Extrusive Rocks Physical Geology 13/e, Chapter 4.
VOLCANISM & Igneous Activity. VOLCANISM Lava = Magma at earth surface –Silica content controls “explosiveness” Pyroclasts = Fragments of rock due.

VOLCANISM & Igneous Activity. VOLCANISM Lava = Magma at earth surface –Silica content controls “explosiveness” Pyroclasts = Fragments of rock due.
Igneous Rocks Section 6.2.

Igneous Rocks Section 6.2.
Chapter 6 – VOLCANOES. Volcanoes & volcanic hazards Volcano –Vent where lava, solid rock debris, volcanic ash, & gases erupt from inside Earth onto its.

Chapter 6 – VOLCANOES. Volcanoes & volcanic hazards Volcano –Vent where lava, solid rock debris, volcanic ash, & gases erupt from inside Earth onto its.
Volcanoes. The Nature of Volcanic Eruptions Viscosity (resistance to flow) determines the “ violence ” or explosiveness of a volcanic eruption Factors.

Volcanoes. The Nature of Volcanic Eruptions Viscosity (resistance to flow) determines the “ violence ” or explosiveness of a volcanic eruption Factors.

Similar presentations

Ads by Google