Textbook Notes (362,902)
Canada (158,096)
Geography (157)
GEOG 1350 (22)
Chapter 4

Chapter 4: Volcanoes

6 Pages
Unlock Document

University of Guelph
GEOG 1350
Jaclyn Cockburn

Volcanoes Chapter 4Vent in the Earths surface magma and gases build up and erupt produces effusive igneous rocksThe type of magma erupted impacts the profile of the Earths surface that is built IntroductionMost volcanoes are near plate boundaries Midoceanic ridges and subduction zones allow molten rock to reach surfaceMagma is molten rock Lava is magma on the earths surface 23 of all active volcanoes are located along the Ring Of Fire subduction zone Magma Described by silica content and amount of dissolved gasses Basalt Most common volcanic rock4552 silica Andesite 5263 silica Dactite 6368 silica Rhyolite 68 silicaMagma also contains small amounts of water vapour and carbon dioxideComposite VolcanoesBuilt from a combination of lava flows and pyroclastic deposits Have a cone shape also called stratovolcanoesEruptions involve andesitic or dactic magma High silica and low viscosityExplosions more violent and dangerous but less frequent Mt St Helens Mt Ranier Mt FujiShield VolcanoesLargest volcanoes in the world Built almost entirely of lava flowsCan also include fragmented debris called tephra Associated with basaltic magmaLow viscosity low gas content no fractionationGentle flowing lava with nonexplosive eruptions Can form lava tubes underground
More Less

Related notes for GEOG 1350

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.