Name
(1)
Chapter 2 Expert Questions
How is lava different than magma?

Magma and lava are both molten rock, which is a combination of melted rock,
mineral crystals, and gases.

However…..
o Magma is deep below Earth’s surface
o Lava has reached Earth’s surface.
(2)
Explain the difference between texture and composition of a rock

Composition – the chemical makeup of a rock that describes either the minerals
or other materials in the rock.
o Example: Limestone = 95% Calcite & 5% Aragonite

Texture – The quality of a rock that is based on the sizes, shapes, and positions
or the rock’s grains
o Example: Siltstone is fine-grained
(3)
In which ways can a rock melt?

3 main ways in which magma forms
o Temperature - When a rock is heated
o Pressure - When pressure is released
o Composition - When a rock changes composition
(4)
How does the cooling rate of magma affect the properties of igneous rock?

The amount of time it takes for magma or lava to cool determines the texture of
igneous rock.
o Fast-cooling lava produces fine-grained igneous rock
o Slow-cooling magma produces coarse-grained igneous rocK
(5)
Compare intrusive and extrusive igneous rock. Which category do plutons fit
under? How are they formed?

Intrusive- Rock formed from the cooling and solidification of magma beneath
Earth’s surface (inside)
o Plutons occur here. They are formed as magma rises upward through the
crust, it sometimes stops moving before it reaches the surface and cools
slowly, forming millions of mineral crystals. When the entire magma body
solidified, it forms plutons.

Extrusive – Rock that forms as a result of volcanic activity at or near the Earth’s
surface (exits)
(6)
Where do sedimentary rocks form? What is the most noticeable feature of
sedimentary rock?

They form at or near Earth’s surface (without the heart and pressure
involved in the formation of igneous/metamorphic rocks).

The most noticeable features are the layers (strata) which are horizontal
layers of rocks that can be visible for miles.
(7)
What factors cause rock to weather into fragments? How do these
fragments travel and what finally happens?

Weathering that causes rock to break into fragments are:
o Wind, water, ice, sunlight, and gravity
o Through the process of erosion, these rock/mineral fragments
(sediments) are moved from one place to another.
o Eventually the sediment is deposited in layers.
o As new layers of sediment are deposited, they cover old layers.
o Older layers become compacted.
(8)
Explain the 3 different ways sedimentary rocks are formed. How do they
differ?

The three different ways sediments are formed are:

Clastic, chemical, and organic.
1. Clastic –rocks cementer together by a mineral
2. Chemical- solutions of dissolved minerals and water
3. Organic – remains (fossils) of once living animals
(9)
Explain how the mineral composition of rocks changes as they undergo
metamorphism

If the temperature or pressure of the new environment is different from
the one in which the rock formed, the rock will undergo metamorphism.
o Contact metamorphism – rock is heated by nearby magma.

When magma moves through the crust, the magma heats the
surrounding rock and changes it (some minerals in the are
changed into other minerals)
o Regional metamorphism- pressure builds up in the rock

Increased pressure and temperature cause rock to become
deformed and chemically change.
(10)
Explain how garnet forms from metamorphic rock

Calcite, quartz, and hematite are exposed to extreme heat and pressure,
which will eventually combine and recrystallize to form the metamorphic
mineral garnet.
(11)
How can metamorphic rock turn into another form of metamorphic rock? (
hint- use foliated rock as an example)

Metamorphic rocks can become other metamorphic rocks if the
environment changes again.
o Example – if slate is exposed to more heat and pressure, the slate
can change into phyllite
o When phyllite is exposed to heat and pressure, it can change into
schist
o More heat and pressure can cause minerals to separate and form
gneiss.
o ALL ARE METAMORPHIC ROCKS!
(12)
How are sandstone and siltstone different from one another? How are they
the same?

Different :
o Sandstone- medium-grained rock
o Siltstone – fine-grained rock

(13)
Same- both types of sedimentary rocks
If you were looking for fossils in the rocks around your home and the rock
type that was closest to your home was metamorphic, would you find many
fossils? Why or why not?
No, because fossils are only found in sedimentary rock.
(14)
Suppose you are writing a book about another planet. In your book, you mention
that the planet has no atmosphere or weather. Which type of rock will you NOT
find on the planet. Explain
You wouldn’t find sedimentary rock because they depend on weathering to form
sediments.