Explore Student Journal: The Rock Cycle locks on Earth can be classified into three categories based on the way they were formed. laneous rocks are formed through voicanic action. Sedimentary ocks are formed by deposition. Metamorphic rocks are formed when existing rocks undergo a change due to extreme heat and pressure. Rocks that have a volcanic origin are classified as igneous and form when magma or lava cools and hardens. As the magma or lava cooks, crystals begin to form. The size of the crystals depends upon how fast the magma or lava cools. If magna cools quickly, small crystals form and can be observed on the rock surface such as in basalt, for example. Lava can cool so quickly that crystals do not have time to form at all, such as with obsidian. If magma cools sloniy. larger erystals fom and can easily be seen on the surface of rock specinens. A common example of igneous rock that exhibits large erystal formation is: granite. When Earth's materials are deposited in layers and pressed together over thee, sedimentary rocks form. The formation of sedimentary rock begins with the deposition of sediments. As layers are added, the oldest or lower layers that were deposited first experience increased pressure. The sediments and the spaces between them are crushed together in a process called compoction. During the cementation process, the sediments are bound togethor when a solution fils in around the particles tike glue. If the sediments deposited are sand particles such as in a beoch environment, sandstone forms. If the sediments are fine sit or day-sized particles, commonly called "rnud," such as those found in basins wodldwide, shaie forms, Limestone typically forms from shells and other sediments deposited in ocean envirenments. A quiet and undisturbed environment will sometimes lead to fossi formation within the layers of endimentary deposition. Metamorphic rock lorms when one type of rock changes into another due to exposure to hest and pressure often caused by movement of material deco beneath Eaths suffece. This change to rock appearance and composition takes an extrenely long time. Metamorphic rocks are often character ixed by wavy layers of mineral crystals or by the presence of unuwal minerals. Any rodk can become a metarnorphle rock. For example, the sed mentary rock ihale forms from layers of depositeds sit. When exposed to high pressure due to geologic processes, the netamorphic rock siate forms. The sedinentary rock sandstone chamses to quatzite when exposed to extreme beat and possure beneath Eartit's surface. Another example of a metamoephic rock is marble which forms when limestone is exposed to extreme temperatures or presure leneous basal changes to sehist in the metamorphic process. The interesting thing about the metamorphic pocess is that any rodk-igneous, metamorphik, or sedinentiry-will change and form new metaniorphic rock given enovgh time. he.M, and/or pretsure. The rock cycle Alwstrates how rocks move on and un.

1. Explore Student Journal: The Rock Cycle locks on Earth can be classified into three categories
based on the way they were formed. laneous rocks are formed through voicanic action.
Sedimentary ocks are formed by deposition. Metamorphic rocks are formed when existing rocks
undergo a change due to extreme heat and pressure. Rocks that have a volcanic origin are
classified as igneous and form when magma or lava cools and hardens. As the magma or lava
cooks, crystals begin to form. The size of the crystals depends upon how fast the magma or lava
cools. If magna cools quickly, small crystals form and can be observed on the rock surface such
as in basalt, for example. Lava can cool so quickly that crystals do not have time to form at all,
such as with obsidian. If magma cools sloniy. larger erystals fom and can easily be seen on the
surface of rock specinens. A common example of igneous rock that exhibits large erystal formation
is: granite. When Earth's materials are deposited in layers and pressed together over thee,
sedimentary rocks form. The formation of sedimentary rock begins with the deposition of
sediments. As layers are added, the oldest or lower layers that were deposited first experience
increased pressure. The sediments and the spaces between them are crushed together in a
process called compoction. During the cementation process, the sediments are bound togethor
when a solution fils in around the particles tike glue. If the sediments deposited are sand particles
such as in a beoch environment, sandstone forms. If the sediments are fine sit or day-sized
particles, commonly called "rnud," such as those found in basins wodldwide, shaie forms,
Limestone typically forms from shells and other sediments deposited in ocean envirenments. A
quiet and undisturbed environment will sometimes lead to fossi formation within the layers of
endimentary deposition. Metamorphic rock lorms when one type of rock changes into another due
to exposure to hest and pressure often caused by movement of material deco beneath Eaths
suffece. This change to rock appearance and composition takes an extrenely long time.
Metamorphic rocks are often character ixed by wavy layers of mineral crystals or by the presence
of unuwal minerals. Any rodk can become a metarnorphle rock. For example, the sed mentary
rock ihale forms from layers of depositeds sit. When exposed to high pressure due to geologic
processes, the netamorphic rock siate forms. The sedinentary rock sandstone chamses to quatzite
when exposed to extreme beat and possure beneath Eartit's surface. Another example of a
metamoephic rock is marble which forms when limestone is exposed to extreme temperatures or
presure leneous basal changes to sehist in the metamorphic process. The interesting thing about
the metamorphic pocess is that any rodk-igneous, metamorphik, or sedinentiry-will change and
form new metaniorphic rock given enovgh time. he.M, and/or pretsure. The rock cycle Alwstrates
how rocks move on and under Earths crust and change from one type of rock into mather. As
rocks move through the rock c erie. their mineral compositions and plrikal ktructures change to
reflect the processes under which they are formed. The rock cycle shows how any rock can
underso chanse to form any odber type of rock. For example an iane ous rock formed by a
volcanic lava flow ean crumble to become sand, the sand can be deposited en a beachand
eventusly be conpacted and cemented to become the sedimertary roek, sandstone. The sadstone
can be buried deep into Carthk crust whero extreme prestwe and heat trom the overhine lyyers
change the sandutone into a netanorphic rosk. Aury rock can be carned so dife P that the
temperature becomes wo areat that the rock melts, becomes magma and is then ready to move
toward the sur face to form new labnous rocks. Unlike lte cycles, rocks do not have to move

2. through each stsge. An igneaus rock can be changed into a metamorphic rock, a metamorphic
rock cis crumble to become a sedimentiry rocki and redinentary rocks can be te-reited to becone
mugna the pathwaya rock takes on the rock cycle depends upon the movenents of the rock that
place the rock in the position to either cumble, bo put under ereat presuure, or melt.What
characteristic is used to determine the three categories?