Volcanoes and Geology ESS Quiz Study Guide

Cinder Cone

Cinder Cone

Usually smaller than 900 meters in height

Cinder Cone

Eruptions usually result in smaller blocks that make up an unconsolidated slopes

Cinder Cone

Small steep volcanoes made up of volcanic debris that builds up around a vent

Cinder Cone

Low explosivity with low viscosity

Composite

Big, violent eruptions (high viscosity)

Composite

Composed of lava flows, pyroclastic deposits, and mudflow (lahar) deposits, as well as lava domes

Composite

Tend to have lava tubes

Shield

Very wide but not very tall

Shield

Made almost entirely of Low viscosity basaltic lava flows

Shield

Most of Hawaii are composed of these types of volcanoes

Different rocks will crystallize at different temperatures. The higher the temperature, the higher in ______ concentration

Calcium

The higher the rock is on the series, the more ____ it is.

mafic

Some rocks are only formed at a certain range of temperatures. If they go past it, it will go back into solution and form slightly different rocks. This is called the

Discontinuous Series

Some rocks slowly change as the temperature shifts. This creates a range of slightly different rocks without fully dissolving. This process also includes the creation of zone crystals. This is called the

Continuous Series

Rocks that are richer in Magnesium (Mg) and Iron (Fe) are

Mafic

Rocks that are richer in Feldspar and Quartz minerals are

Felsic

Rocks that are darker in color (if they have crystals), and denser are

Mafic

Rocks that are lighter in color (if they have crystals), and lower density are

Felsic

Rocks are formed from lower viscosity magma, causing them to cool faster are

Mafic

Rocks are formed from high viscosity magma, causing them to cool slower are

Felsic

Color can only be used to classify rocks if

the rock has crystals

Rocks that have larger crystals and are more coarse rocks are usually classified as

Intrusive

Rocks that have smaller or no crystals are usually classified as

Extrusive

Rocks that are cooled deep underground are

Intrusive

Rocks that are cooled above/near Earth’s surface are

Extrusive

Rocks that are glassy are usually classified as

Extrusive

Crystals larger than 1 cm; very slow cooling of magma

Pegmatitic

Crystals about 1-10 mm; slow cooling of magma

Phaneritic

Large and small crystals both; slow and then fast cooling of magma or changes in viscosity

Porphyritic

Crystals are present but are not visible from the human eye; rapid cooling of magma

Aphanitic

Glassy texture; rapid cooling of magma and/or very poor nucleation

Glassy

Meringue-like shaped; rapid cooling of gas-filled lava

Vesicular

Holes/Bubbles; gas bubbles in the lava that escape

Vesicular

Mixture of rock fragments

Pyroclastic

Is Pegmatitic usually intrusive, extrusive, or either

intrusive

Is Phaneritic usually intrusive, extrusive, or either

intrusive

Is Porphyritic usually intrusive, extrusive, or either

either

Is Aphanitic usually intrusive, extrusive, or either

extrusive

Is Glassy usually intrusive, extrusive, or either

extrusive

Is Vesicular usually intrusive, extrusive, or either

extrusive

Is Pyroclastic usually intrusive, extrusive, or either

extrusive

A pipe where magma from the interior can rise to Earth’s surface

Volcanic Pipes

Magma that was rising but did not erupt so it cools. After centuries of erosion and weathering, the soft rock around the volcano weathers off so this cooled magma stays as a

Volcanic Neck

A tabular structure formed from magma entering fractures of rocks (vertical)

Dike

A tabular structure formed from magma entering fractures of rocks (horizontal)

Sill

A body of magma in between rock layers

Laccolith

A massive, intrusive igneous rock formation that was once a large amount of magma.

Batholith