Question

relative dating and age of rocks vocabulary
directions: match each description to its answer by writing the corresponding letter on the line.

1. ______ law of superposition

a. a fossil known to have lived in a specific time period that is used to determine the relative age of surrounding rocks

1. ______ cross - cutting relationships

b. a section of magma that solidifies beneath earth’s surface after pushing through rock layers and is younger than the rocks around it

1. ______ stratigraphy

c. the principle that states that a geologic feature that cuts through an arrangement of rock layers is younger than the rocks it cuts through

1. ______ index fossil

d. a method to determine the age of rocks by comparing their layer arrangement

1. ______ relative dating

e. the number of years since a rock was formed

1. ______ unconformity

f. a crack in two blocks of rock where movement occurs

1. ______ intrusion

g. a gap in the age of rock layers due to erosion

1. ______ extrusion

h. the principle that states that the oldest rocks are at the bottom and the youngest are at the top of a series of undisturbed rock layers

1. ______ absolute age

i. the classification of rock formed by the cementation of sediments

1. ______ relative age

j. a section of lava that solidifies on earth’s surface and is younger than the rocks below it

1. ______ sedimentary rock

k. the age of a rock compared to the age of other rocks, not a specific time of formation

1. ______ fault

l. the study of the order of rock layers (strata)

Explanation:

Each term is matched to its geologic definition based on core concepts of relative dating and rock formation:

1. Law of superposition defines the age order of undisturbed rock layers.
2. Cross-cutting relationships state cutting features are younger.
3. Stratigraphy is the study of rock layer order.
4. Index fossils are time-specific for dating rocks.
5. Relative dating compares rock ages via layer arrangement.
6. Unconformity is an erosion-caused age gap in layers.
7. Intrusion is subsurface solidified magma.
8. Extrusion is surface-solidified lava.
9. Absolute age is the exact formation age in years.
10. Relative age is a rock's age vs. other rocks.
11. Sedimentary rock forms from cemented sediments.
12. Fault is a moving crack between rock blocks.

Answer:

1. h. the principle that states that the oldest rocks are at the bottom and the youngest are at the top of a series of undisturbed rock layers
2. c. the principle that states that a geologic feature that cuts through an arrangement of rock layers is younger than the rocks it cuts through
3. l. the study of the order of rock layers (strata)
4. a. a fossil known to have lived in a specific time period that is used to determine the relative age of surrounding rocks
5. d. a method to determine the age of rocks by comparing their layer arrangement
6. g. a gap in the age of rock layers due to erosion
7. b. a section of magma that solidifies beneath Earth's surface after pushing through rock layers and is younger than the rocks around it
8. j. a section of lava that solidifies on Earth's surface and is younger than the rocks below it
9. e. the number of years since a rock was formed
10. k. the age of a rock compared to the age of other rocks, not a specific time of formation
11. i. the classification of rock formed by the cementation of sediments
12. f. a crack in two blocks of rock where movement occurs