Unit 3 STUDY GUIDE
Rocks & Minerals: Chapters 5 & 6
1. The two most common elements in Earth’s crust are
2. What are the two main groups of minerals?
3. What two elements must be present in a silicate?
4. A mineral is described as fluorescent when it _____ under _____ light.
5. What mineral property involves iron?
6. Because many minerals are similar in color and certain elements may change the color, color (is/is not) a good identifier.
7. List the four criteria for determining whether or not a substance is a mineral?
8. The color of a mineral in powdered form is called the mineral’s
9. A ______is a natural solid that usually is inorganic, with characteristic physical properties.
10. The hardest mineral on the Mohs hardness scale is ____.
11. Density is the ratio of
12. Light that is reflected from a mineral’s surface is called
13. Cleavage is the tendency of a mineral to
14. A measure of the tendency of a chemical compound to ______rather than break down to form a different chemical is called chemical stability.
15. What changes the form of existing rock?
16. The name for this type of rock means “changed form.”
17. Three factors that determine whether rock melts are temperature, the presence of fluid in the rock, and
18. Most metamorphic rock forms as a result of _____ metamorphism.
19. What type of rock texture results when extreme pressure causes minerals in metamorphic rock to realign, or when minerals separate out into dark and light bands?
20. Sedimentary rock that is made up of rock fragments that become compacted or cemented together is
21. The series of changes that describes how geologic forces cause rock to change from one type to another is known as
22. The process in which one type of rock changes into another type of rock because of chemical processes or changes in temperature and pressure is called
History of the Earth Chapters 8 & 9
1. The principle that Earth’s history can be explained by current geologic processes is
2. Younger layers of undisturbed sedimentary rock are above older layers according to law of ______.
3. The boundary between two sedimentary rock layers is called a(n)
4. The age of an object in relation to the ages of other objects is
5. A fault or body of rock is younger than any other body of rock it cuts through according to the law of
6. The numeric age of an object is called
7. How much sedimentary rock is deposited over 1,000 years?
8. Carbon-14 is an isotope used ot date objects less than ______years old.
9. How many years of deposition are represented by a single varve?
10. Rates of erosion are not used to date geographical features over a million years old because
11. Index fossils found in rock layers in different areas of the world indicate that the rock layers
12. Almost all fossils are discovered in
13. Amber is
14. A frozen organism does not decay because
15. Organisms that formed index fossils lived during ______spans of geologic time.
16. A varve is most like a(n)
17. The way fossils are formed in very dry places is called
18. What is amber?
19. What is a coprolite?
20. If an igneous intrusion is observed through a layer of sedimentary rock, what geological law applies?
21. Using rates of erosion to determine the absolute age of a geologic feature is practical only for features formed within the past
22. Why is radioactive decay used to determine the absolute age of rocks? Radioactive decay happens at a relatively ______rate.
23. How is radioactive decay used to determine the absolute age of rocks?
24. What is a gastrolith?
25. Fossil imprints are
26. The principle of uniformitarianism states that
27. List all ways that organisms can be fossilized?
28. How many half-lifes would be necessary for a sample of parent isotopes to decay to the point that only one-fourth of the sample is composed of parent isotopes?
29. In radiometric dating, scientists compare the proportion of a radioactive parent isotope to a stable
30. One method used to estimate the absolute age of a stream is to measure
31. Scientists created the first geologic column by determining the relative ages of sedimentary rock in
32. If the Cretaceous Period began about 146 Ma, this means it began
33. Geologic time is divided into
34. Precambrian time consists of
35. A geologic period is usually named for
36. The gradual development of new organisms from preexisting organisms is called
37. Which of the following accurately characterizes Precambrian rock?
38. The division of geologic time that makes up about 88% of Earth’s history is called
39. Scattered landmasses on Earth merged into a supercontinent during
40. The Devonian Period is also known as the Age of
41. The mass extinction at the end of the Permian Period led to
42. The two major groups of dinosaurs during the Jurassic Period were the saurischians and the
43. According to the impact hypothesis, dinosaurs became extinct when
44. The Cenozoic Era is known as the
45. The Pleistocene Epoch was characterized by
46. The Pliocene Epoch began about 5.3 Ma, or
47. The Precambrian rock record is difficult to interpret because
48. The appearance of many new life-forms during the first period of the Paleozoic Era was probably aided by the development of
49. The most common Precambrian fossils are
50. The first period of the Mesozoic Era was called the
51. The first amphibians, which appeared during the Devonian Period, were from the genus
52. The end of the Permian Period was marked by
53. An armored Cretaceous dinosaur was called the
54. What happened when temperatures decreased during the ice ages of the Cenozoic Era?
55. On a geologic column, the oldest rocks
56. Mountain ranges created during the Cenozoic Era include the
57. Scientists have most accurately determined the absolute ages of rock layers by
58. Which of the following explains the concept of evolution brought about by geologic change?
59. Nearly half the Earth’s valuable mineral deposits are found in rocks from ____ time.
60. A variety of life-forms appeared in the Cambrian Period due to
61. What can a scientist assume about a rock layer that matches a similar layer in a geologic column?
62. Dinosaurs became extinct at the end of the
63. The period during which land plants such as ferns and cone-bearing plants began to develop was called the
64. Coal deposits found in Pennsylvania, Ohio, and West Virginia represent fossilized remains of
65. Dinosaurs first appeared during the