Download Identifying Rocks

Identifying Rocks
Environmental Science
Name: ____________________________ Period __________ date: _________
Essential Question: How do I Identify rocks?
Igneous Rock is formed when a magma
cools underground and crystallizes or when
it erupts unto the surface of the ground, cools
and crystallizes. Magma that erupts onto the
surface is called lava. When magma cools
slowly underground the crystals are large
enough to see. When it cools quickly on the
surface, the crystals are very small and you
would need a magnifier or a microscope to
see them. Sometimes, when the magma
cools very quickly, it forms a kind of black
glass that you cannot see through.
1. How do igneous rocks form?
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2. What is lava?
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3. When can a black glassy igneous rock ( obsidian ) form?
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4. Light colored igneous rocks are called Felsic. Give two examples of Felsic rocks.
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5. Dark colored igneous rocks are called mafic. Give three examples of Mafic igneous rock.
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6. Name four examples of igneous rocks that formed underground.
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7. Between the two Felsic igneous rock. Which has bigger crystals? (Rhyolite or Granite) Explain.
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8. Between the two Mafic igneous rocks. Which has bigger crystals? ( Basalt or Gabbro ) Explain.
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Sedimentary Rock forms from particles, called
sediment, that are worn off other rocks. The
particles are sand, silt, and clay. Sand has the
largest particles while clay has the smallest. If
there are a lot of pebbles mixed with the sand, it
is called gravel. The sediment gets turned into
rock by being buried and compacted by pressure
from the weight above it. Another way it
becomes rock is from being cemented together
by material that has been dissolved in water.
Often, both cementing and compaction take place
together.
9. Where do sedimentary rocks form?
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10. What do you call the particles that make up sedimentary rocks?
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11. How do sedimentary rocks form?
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12. Which among the following sedimentary rocks has the largest particles?
(shale, sandstone, conglomerate, breccia): ____________________________________________
13. Which among the following sedimentary rocks has the smallest particles?
(shale, sandstone, conglomerate, breccia): ____________________________________________
14. Which of the two sedimentary rocks has sharp texture? (conglomerate or breccia ) Explain.
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Metamorphic Rock is formed by great heat, or
pressure, or both. The pressure can come from being
buried very deep in the earth's crust, or from the
huge plates of the earth's crust pushing against each
other. The deeper below the surface of the earth, the
higher the temperature, so deep burial also means
high temperatures. Another way that high
temperatures occur is when magma rises through the
earth's upper crust. It is very hot and bakes the rock
through which it moves. Hot liquids or gases from
the magma also can cause chemical changes in the
rock around the magma.
15. How are metamorphic rock formed?
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16. Why is there higher temperature and pressure deeper below the earth’s surface?
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17. Based on the picture. Which metamorphic rock was formed with the lowest temperature and pressure?
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18. Based on the picture. Which metamorphic rock was formed with the highest temperature and pressure?
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19. Based on the picture. Which of these two metamorphic rocks ( marble and schist ) was formed with
higher temperature?
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20. Based on the picture. Which of these two metamorphic rocks ( marble and serpentinite ) was
formed with higher pressure?
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21. Based on the picture. Which of these two metamorphic rocks ( schist and quartzite ) was
formed with higher temperature?
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http://www.rockhounds.com/rockshop/rockkey/index.html
These are both made up words used to indicate the chemical composition of silicate
minerals, magmas, and igneous rocks.
Mafic is used for silicate minerals, magmas, and rocks which are relatively high in the
heavier elements. The term is derived from using the MA from magnesium and the FIC
from the Latin word for iron, but mafic magmas also are relatively enriched in calcium
and sodium. Mafic minerals are usually dark in color and have relatively high specific
gravities (greater than 3.0). Common rock-forming mafic minerals include olivine,
pyroxene, amphibole, biotite mica, and the plagioclase feldspars. Mafic magmas are
usually produced at spreading centers, and represent material which is newly
differentiated from the upper mantle. Common mafic rocks include basalt and gabbro.
(Please note that some geologists with questionable motives switch the order of the
magnesium and iron and come up with the term "femag." This term is not to be confused
with Femag, the dull-witted henchman of the Diabolical Dr. Saprolite.)
Felsic, on the other hand, is used for silicate minerals, magmas, and rocks which have a
lower percentage of the heavier elements, and are correspondingly enriched in the lighter
elements, such as silicon and oxygen, aluminum, and potassium. The term comes from
FEL for feldspar (in this case the potassium-rich variety) and SIC, which indicates the
higher percentage of silica. Felsic minerals are usually light in color and have specific
gravities less than 3.0. Common felsic minerals include quartz, muscovite mica, and the
orthoclase feldspars. The most common felsic rock is granite, which represents the
purified end product of the earth's internal differentiation process.
http://jersey.uoregon.edu/~mstrick/AskGeoMan/geoQuerry11.html