C I NDER CONE VOLCANOSBY T H E GR E AT TA BLE 2

G E N E RA L C H A RAC T E R I S T I C S

• Also called a scoria cone, is a volcano composed of volcanic cinders (scoria) or small, rough particles of hardened lava. When lava that is highly charged with gas bubbles erupts from a vent under pressure, it tends to shoot straight up into the air. This effect is called a fire fountain, and it can sometimes be hundreds of meters high. Blobs of the frothy lava break apart, cool quickly, and fall relatively close to the vent. Over time, a cone-shaped hill builds up around a circular crater.

M OD E O F F O R M AT I O N

• They are built from particles and blobs of congealed lava ejected from a single vent. As the gas- charged lava is blown violently into the air, it breaks into small fragments that solidify and fall as cinders around the vent to form a circular or oval cone. Most cinder cones have a bowl-shaped crater at the summit and rarely rise more than a thousand feet or so above their surroundings. Cinder cones are numerous in western North America as well as throughout other volcanic terrains of the world.

T Y P E O F M AG M A

• Felsic ( very explosive) high in silica has pyro clastic materials ( such as tephra)

L I K E LY T O BE F O U N D

• It is divergent plate boundary.

F O U N D I N T H E U . S .

• Twins butte

• Rocky butte