Download Chapter 4 Review sheet Answers

Chapter 4 Review sheet Answers
1. Define a rock- a rock is a mixture of minerals, rock fragments,
volcanic glass, organic matter, or other natural materials.
2. The process that illustrates how rocks are created and changed is
called the what?
Rock cycle
3. To become an igneous rock, what must magma or lava do? it
must cool and harden
4. To become a sediment, what must other rocks do? they must
weather and erode
5. To become a sedimentary rock, what must happen to the
sediments? they have to compact or cement together.
6. To become a metamorphic rock, what must a sedimentary rock be
subjected to? must have heat, pressure, and/or a chemical change
occur
7. According to the rock cycle, do the rocks have to follow one path
or can they go in many directions? many directions
What determines the path they will take? depends on what
conditions it is being subjected to
8. Describe how the rock cycle supports the principle of conservation
of matter.
The chemical elements in the rocks are not created or destroyed they
are just changed or redistributed into other ways to make up new
rocks.
9. What was the name of the scientist who recognized that rocks
undergo profound changes? James Hutton
What place did he study to notice this? Siccar Point in Scotland
10. How does igneous rock form? hot magma (lava) cools and
hardens to form an igneous rock.
11. What is the difference between magma and lava? magma is hot
rock below ground and lava is hot rock on the surface
12. Where are intrusive rocks found? inside the earth, magma cools
under the surface
What characteristics supports where it formed? big crystals have
formed
How did these rocks cool? very slowly
13. Where are extrusive rocks found? on the earth’s surface from
lava cooling
What characteristics supports where it formed? it has very small
crystals
How did it cool? it cooled fairly quickly so large crystals could not set
up.
14. How did pumice and scoria form? these rocks are full of holes.
Some of these were cooled as the lava was shot up into the air and
as it spun it the air. Other have air pockets that have created holes
as the rock cools very quickly.
15. How did obsidian rock form? it cooled immediately as it flowed
into water. No chance for minerals to line up so we have no idea
what is in it.
16. What color are basaltic rocks? dark in color Why does it have
the color it has? because it has a lot of iron and magnesium in the
magma which give it a dark color.
17. What color are granitic rocks? they are lighter in color Why does
it have the color it has? granitic rocks are made up of a lot of silica
which is lighter in color.
18. How can you describe what an andesitic rock is like? andesitic
rocks are a cross between granitic and basaltic magma. At times it
might have more silica and at other times it will have more
iron/magnesium. The composition is between the two of them.
19. What 3 conditions cause rocks to change into metamorphic
rocks? increases in temperatures, increase in pressure, or being
exposed to hot, watery fluids can change it chemically.
20. Describe the characteristics that places rocks in a foliated
texture. mineral grains are lined up in parallel layers. The minerals
could form bands or get pressed together so tightly that they form
layers of rocks like slate.
21. Slate forms from shale. Gneiss forms from granite.
22. Describe a non-foliated textured rock. The mineral grains grow
and rearrange but they don’t form layers.
23. Quartzite forms from sandstone. Marble forms from limestone.
24. What is the most common rock on earth? Igneous rock
25. What is the most exposed rock type? sedimentary rock What %
is exposed? 75%
26. Define sediments- loose materials such as rock fragments,
mineral grains, bits of shell that have been moved by wind, water, ice,
or gravity.
27. List at least 5 examples of sediments: gravel, pebbles, sand, silt,
clay, shells, dead plant material, boulders
28. How are sedimentary rocks formed? they are formed when
sediments are pressed and cemented together, or when minerals
form from solutions.
29. Sedimentary rocks are usually in layers.
30. What are detrital sedimentary rocks made of? other rock pieces
31. What is the difference between weathering and erosion?
weathering is the breaking down of rocks into smaller pieces and
erosion is taking those smaller pieces and moving them to another
area.
32. Describe compaction: when layer upon layer of sediments build
up, pressure is applied to the lowest layers and the particles stick
together because they have been pushed together.
33. Describe cementation: water moving through soil picks up
minerals that can move through the open spaces of the sediments.
When the water evaporates, these minerals are left behind forming a
glue that holds the sediments together.
34. What do rounded sediments tell us? that the sediments have
been in running water for a long time.
35. List the 4 detrital rocks and what they are made of:
Shale- clay
Siltstone- silt
Sandstone- sand
Conglomerate- gravel
36. How do chemical rocks form? they form as dissolved minerals
come out of solution and form a rock.
37. Describe how most limestone formed: calcium carbonate is
carried in solution in ocean water. As the ocean water evaporated,
the CaCO comes out of solution and the crystals grow together to
form a rock.
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38. Describe how most rock salt forms: as the water rich in
dissolved salts evaporates, it deposits the halite.
39. What are organic rocks formed from? they are formed from the
remains of once-living things.
40. What is fossil-rich limestone made of? animals such as mussels,
clams, corals, snails have shells that accumulate on the ocean floor.
If these shells are cemented together, fossil-rich limestone forms.
41. What is chalk made of? microscopic shells of marine organisms.
42. What mineral are all shells made of? calcium carbonate or
CALCITE
43. How did coal form? dead plants are buried under sediments in
swamps. Microorganisms chemically change the plant material to a
black gooey mess. Over millions of years this material is compressed
and hardens into a rock that burns.
44. Why is coal considered a non-renewable resource? it takes
millions of years to form.