Chapter 13 - Geologic time

Question 1

principle of superposition

Answer 1

in sedimentary rocks the oldest layer is on the bottom and youngest layer is on the top

Question 2

principle of original horizontality

Answer 2

sedimentary rocks originally formed parallel to the surface of earth

Question 3

principle of original lateral continuity

Answer 3

faulting, severe folding, and erosion may separate originally continuous strata

Question 4

principle of cross-cutting relationships

Answer 4

rocks that cut across other layers of rock are younger than the rock that they cut across

Question 5

principle of inclusions

Answer 5

any existing rock that is incorporated into a sedimentary layer or igneous intrusion is older than the layer or intrusion which it is incorporated within

Question 6

principle of unconformities

Answer 6

unconformities develop when erosion or non-deposition interrupts the continuity of the geologic record

Question 7

principle of fossil succession

Answer 7

plants and animals change throughout time and the rock layers record the change

Question 8

unconformity

Answer 8

when a sedimentary layer is on top of an eroded igneous layer

Question 9

disconformity

Answer 9

when a sedimentary layer is on top of an eroded sedimentary layer

Question 10

alpha decay

Answer 10

an atom emits an alpha particle consisting of 2 protons, 2 neutrons

Question 11

beta decay

Answer 11

an atom emits a negative particle which changes a neutron into a proton

Question 12

electron capture

Answer 12

an atom loses one proton and becomes lighter