earth science test 10 Flashcards
What is the largest volcano in europe
Mount etna in sicily
what is a volcano? lava?
volcano is a weak spot in the crust where magma from mantle rises to the surface then called lave .
what is magma adn where is forms
magma is a mixture of partially melted mineral crystals dissolved gases and water. It forms in the crust and upper mantle when solid rock partially melts.
what are the factors magma depends on to form
Heat,Pressure, and water content
Heat
Deep down rock is near its melting point becuase its really hot. But other things like friction of huge slabs of lithosphere sliding past each other in subduction zone. mantles heat and hot mantle rock can rise and intrude into cooler lithosphere heating it.
Pressure
as you go deeper pressure gets more pressurized. decompression melting occurs when rock rises and melts due to reduced pressure. hot mantle rock can rise and intrude into cooler lithosphere heating it. as pressure decreases and rock melting point decreases.
Water content
increasing water content of rock also lower rock melting point.
volcano plate boundarie
volcano is an opening in earths surface that often forms a mountain when layers of lava and volcanic ash erupt.
what is the most active volcano
kilaeua in hawaii.
what is the land of fire and ice
the island of iceland in the north atlantic ocean near the arctic circle has some glciers and volcanoes know as that.
how was iceland formed
sometimes volcanoes and rift eruption rise above sea level forming islands such as iceland.
what is convergent boundary volcanism
when an plates collide one goes down. water from the oceanic lithosphere lowers melting point melting begins. magma migrates upward forming volcanoes.
convergent volcanism pt 2
oceanic plates slide under continental platesas one plate slides under the other the rock gets deep enough that it is hot enough to cause partial meltling. the magna is less dense and foces its way up cracks forming volcanoes. these volcanoes are the more violent type
what is the ring of fire.
a belt of volcanoes that circles the Pacific Ocean
intraplate volcanism
occures within a plate. mantle plumes are areas wheere he mantle is unusually hot as a rsult hor rock is forced upward toward the curst decompression meltin goforms magma. the magma that reaches the surface forms volcanoes. volcanoes may rise above sea level and form islands
what are hot spots
a volcanic region that results from magma plumes.
why are some volcanoes crazy explosive and some are not
becuase of characteristics of magma and the amount of dissolved gases in the magma.
what is viscosity
the substances resistance to flow.
what does viscosity tell you about an eruption
more viscous the magma more violent the eruption but the less viscous the less violent the eruptions.
what makes viscosity
the more silica the more viscosity there is
dissolved gases
the gases trapped in the magma provide the force to propel lava out the vent the volcanoes opening at the surface.
explain a volcanic eruption
under the surface the dissolved gas in the magma are under a lot of pressure as magma approaches the surface the pressure is greatly reduced the dissolved gases expand forming large bubbles exert an enormous force when a volcano erupts the force of expanding gases pushed magma up which become lava the remaining gases bubble put.
what are the three different types of plutons
batholiths stocks sills lacoliths dikes.
what is decompression melting
when rock rises and melts due to reduced pressure
what is a vent
the volcanoes opening at the surface
what rock type goes with what.
basaltic:sheild volcanoes, basalt plateaues, and cinder cones.
andesetic:composite cones
Granitic: Pyroclastic flows, volcanic domes
volcanic material
depending on the tyope of eruption volcanoes may produce lava flows or eject pyroclastic material or both. and lots of gas.
what are the two types of lava characteristics
Pahoehoe and aa. Pahoehoe is hotter and fast moving basaltic lava relatively smooth blue c=black skin. AA is coller slower moving basaltic lava which forms jagged rough blocks with sharp projections.
gas sampls got during a hawai volcanoe was
70 water 15 carbon dioxide 5 nitrogen 5 sulfur
what are pyroclstic materials
particls produced in volcanic eruptions
what are lapilli
particles that range in size from small beads to walnuts 3-64mm in diameter
what are blocks and bombs
particles larger than 64mm in diameterare called blocks when they are made of hardened lava and bobmbs when they are ejected as glowing lava.
what are the three main types of volcano
shield volcanoes, cinder cones, and composite cones.
waht builds volcanoes
repeaeted eruptiond of lava or p yroclasyic material eventually build it
shield volcanoes
are produce by the accumulation of fluid basaltic lavas,resemble warrior shields and grow from bottom of ocean.
cinder cones
ejected lava fragments that harden in the air and fall around a vent can builda cinder cone. once erupted for about a few weeks will never erupt again
composite cones
these one are the most dangerous volcanoes. its a large nearly symmetrical volcanic mountain composed of layer of both lava and pyroclastic deposits. most of these are in the ring of fire.
what is it called when magma forces its way through cracks but fails to reach the surface
intrusive feaetures
what are plutons and classificiaitons
plutons are the structures the underground magma forms when it cools. size shape and relationship to surrounding rock
sills and lacoliths
are plutons that form when magma intrudes between rock layers close to the surface then hardens.
what are dikes
dikes are plutons that forms when magma from magma chamber moves into fractures that cut upward throught the rock layers
what are batholiths
a large mass of igneous rock that cooled and hardened below the surface, then was uplifted and exposed at the surface by erosion.
what is a caldera
a huge hole left by the collapsed of a volcanic mountain. it occurs after an enourmous eruption that empties the vent and magma chamber
what are volcanic necks
they form when magma hardens in a volcanoes pipe. the softer rock of tephera of a cincer cone around the pipe wears away.
what is a lava plateaued
instead of forming mountians some eruptions from lava plateueas. platuaes are high and level platforms.
