VOLCANOESBrianna Ehlers

Cinder Cone

Cinder cone volcanoes are also called scoria cones volcanoes. Scoria is a vesicular, low density basalt. Cinder cone volcanoes are built from ejected lava fragments. The lava is driven out by expanding gas bubbles. It also expands in all directions. The way pressure is relieved is through vents that are usually relatively vertical.

Composite

Earth’s most picturesque yet potentially dangerous volcano.

Also known as composite cones or stratovolcanoes.

Mostly located near a narrow zone that rim s the Pacific ocean, which is known as the ring of fire.

Examples: Mount St. Helens, Mount Shasta, and Mount Garibaldi.

Shield Volcanoes

Shield volcanoes are produced by the accumulation of fluid basaltic lava. The shape is broad, slightly domed, and looks like a warriors shield. most of the shield volcanoes begin to form on the ocean floor as seamounts.

Some shield volcanoes grow large enough to form volcanic islands. Similarly most oceanic islands are either single shield volcano, or more commonly two or more.

Other Volcanic Landforms

A caldera is a large depression at the summit of a volcano formed when magma is withdrawn or erupted from a shallow underground magma reservoir.

Lava domes are common in volcanic regions. Lava domes can come in many shapes and sizes, they aren’t as cool as the known volcanoes but they are still a sight to see.

Flood basalts are yet another strange type of "volcano. These flows are slow moving with most of the thickness coming by injecting lava into the interior of an initially thin flow.

Materials Extruded During an Eruption

Lava Tubes: Hardened basaltic flows commonly contain cave like tunnels.

Block Lava: Short prominent flows, their upper surface consists of vesicle – free, detached blocks.

Pillow Lava: Lava flow composed of numerous tube-like structures.

Gases: Magma contains and assortment of dissolved gases (volatiles), held in the molten rock by confining pressure.

Pyroclastic Materials: When volcanoes erupt they eject pulverized rock, lava, and glass fragments from the vent. The particles produced are referred to as pyroclastic materials. Fragments range in size, from very fine dust to sand sized volcanic ash.

Lava

Aa and Pahoehoe lava flows are both Hawaiian names.

Aa Lava• rough jagged block

surface• dangerously sharp edges• erupt from the same

vent• Less fluid than

pahoehoe lava flows

Pahoehoe• smooth surface• often resemble twisted braids of

ropes• pahoehoe means, “on which one

can walk.”• erupt from the same vent• can change into Aa lava

Mount Vesuvius

The Roman city of Pompeii was destroyed in AD 79 during an eruption of Mount Vesuvius. In the picture you see is the after math of this massive eruption.

Excavation began in the 18th century and continues today. Plaster casts of several victims of the AD 79 eruption.

Works Cited http://skywalker.cochise.edu/wellerr/students/volcano-types/project_files/image006.jpg

http://www.dnr.wa.gov/SiteCollectionImages/Places/ger_volcanoes_mtrainier.jpg

http://mail.colonial.net/~hkaiter/Aaascienceimages2137/eruption1.jpg

http://www.geology.sdsu.edu/how_volcanoes_work/Images/Calderas/crater_lake_s.jpg

http://images.fineartamerica.com/images-medium-large/the-basalt-cones-of-the-djado-plateau-michael-fay.jpg

http://volcano.oregonstate.edu/sites/default/files/LavaDome.jpg

http://volcanoes.usgs.gov/Imgs/Jpg/Kilauea/30212265-054_large.jpg

http://www.marlimillerphoto.com/images/Ig-98.jpg

http://geology.com/volcanoes/vesuvius/pompei-garden-of-fugitives.jpg

http://volcano.oregonstate.edu/cinder-cones

http://volcano.oregonstate.edu/book/export/html/443

http://volcano-pictures.info/glossary/caldera.html

http://volcano.oregonstate.edu/flood-basalts

I also used the textbook; Earth: An Introduction to Physical Geology, Tenth Edition.

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