{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

5 volcanoes - Volcanism and Volcanic Hazards Magma...

Info iconThis preview shows pages 1–9. Sign up to view the full content.

View Full Document Right Arrow Icon
Volcanism and Volcanic Hazards abcnews.go.com
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Magma Formation Remember: The mantle is solid! Three ways to form magma: 1.Decompression 2.Add Volatiles – H 2 0 & CO 2 3.Heat Transfer PRESSURE
Background image of page 2
Magma Composition All magma contains Silicon (Si) and Oxygen (O) with varying amounts of Al, Ca, Na, K, Fe and Mg - The amount of silica (SiO 2 ) distinguishes the magma Felsic – High silica (>65%) Intermediate – moderate silica (50-60%) Mafic – Low silica (40-50%) Ultra-mafic – Very low silica (30-40%)
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Magma Composition What kind will we have? Main factor: Source rock composition Secondary: Partial Melting Assimilation Magma Mixing
Background image of page 4
Magma Movement
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Volcanoes are surface expressions of subsurface igneous activity www.geo.ua.edu Defined by eruptive history: Active : Historical eruption Dormant : Capable of eruption Extinct : No activity Presently - 550 active volcanoes globally
Background image of page 6
Eruption Types Explosive vs. Nonexplosive Factors that control eruptive style of a volcano: 1. Composition 2. Temperature 3. Volatiles www.geo.ua.edu
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Eruption Types These factors affect the magma’s viscosity - Viscosity: material’s resistance to flow Temperature – hot magma is less viscous Composition – Silica content High SiO 2 = Felsic = High viscosity Low SiO 2
Background image of page 8
Image of page 9
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}