Today: 11/30/15 Monday  Pick up a copy of the guided notes paper on the front stool. We’ll be starting volcanism today. I’ll give you guys/gals a heads-up on the model project you’ll be working on for this unit.

Today: 12/1/15 Tuesday  Honors: Turn in your text book to page 248.  CP: Get a copy of the data sheet on the front stool.

Chapter 18 - Volcanoes 18.1 Volcanism

Volcanism  Describes all processes associated with the discharge of magma, hot fluids, and gases w.kidsgeo.com/images/volcanicim.jpg&imgrefurl= volcanism.php&h=200&w=300&sz=10&hl=en&st art=5&tbnid=2qhJLJRLrxKp3M:&tbnh=77&tbnw =116&prev=/images%3Fq%3Dvolcanism%26gbv %3D2%26hl%3Den

Magma  Slushy mixture of molten rock, mineral crystals, and gases  Lava = magma that reaches the surface /GEO99/pubigneous/liquidlava.jpg

Volcanoes  Distribution of volcanoes is not random  Most from at Plate Boundaries  Majority are at convergent and divergent boundaries

Convergent Volcanism  Occur at subduction zones  Oceanic plate descends into mantle  Magma moves upward  Mixes with rocks, minerals, and sediment  Form explosive volcanoes

Subduction Zone

Two Major Belts of Convergent Volcanoes  Circum-Pacific Belt  Mediterranean Belt

Divergent Volcanism  Occurs where plates are moving away from each other  New floor forms as magma rises  Non-explosive, Large amounts of lava  Mostly underwater volcanoes

Hot Spots  Unusually hot regions of mantle where high- temperature plumes of magma rise to the surface  Ex: Hawaiian islands  Rate of plate movement can be calculated from position of volcanoes

Hot Spot Formation  Hot spot remained stationary but Pacific plate slowly moved northwest  Left trail of islands

Flood Basalts  Non-viscous lava that flows through surface of Earth out of cracks called fissures

Notes 18.1 B Continue “Volcanoes”

Anatomy of Volcano  Conduit = tubelike structures through which lava flows  Vent = opening where lava reaches surfae  Lava cools and solidifies  Over time it accumulates to form a volcano

Anatomy of Volcano  Crater = bowl-shaped depression at top of volcano  Calderas = large depressions formed when magma chamber is emptied

Caldera

Types of Volcanoes  Shield  Cinder cone  Composite/Stratovolcano

Shield Volcanoes  Broad, gently sloping sides  Circular base  Formed as layers of lava accumulate from non- explosive eruptions

Shield Volcano JPG ges/MaunaLoa79_mauna_loa_shield_volcano_05 -79_med.jpg

 Mauna Loa, Hawaii  Shield Volcano

Cinder Cone Volcanoes  Steep slopes, generally small  Form as small pieces of magma are ejected into the air  Pieces = tephra – pile around vent

Cinder Cone ete/images/modules/volcanoes/typesa.GIF&imgrefurl= ww.cotf.edu/ete/modules/volcanoes/vtypesvolcan1.html&h=236 &w=265&sz=13&hl=en&start=4&tbnid=1cbnv3DoRKQHNM:&tb nh=100&tbnw=112&prev=/images%3Fq%3Dcinder%2Bcone% 2Bvolcano%26gbv%3D2%26hl%3Den uscara_j/toolsvis/images/colorcinderc one2.jpg

Composite Volcanoes  Cone-shaped with concave sides, much bigger than Cinder Cone  Formed of layers of hardened chucks from violent erupts alternative with layers of lava oozing down slope

Composite Volcanoes ers/primary/yu_neng_pri_volcano_nc/xplopix 9.gif neng_pri_volcano_nc/versuviu s.htm

Mount Vesuvius

In-Class Assignment  Volcano Cube