Laboratory Manual for Introductory Geology 4e

EXERCISE 18.2
Name:
Course:
Short-Term Changes in the Geosphere (continued)
Section:
Date:
Continental Movement
The New England seamount chain formed as the North American Plate moved over a hot spot originally located near
Hudson Bay in Canada. The map below traces the movement of the North American Plate above the hot spot over time
by connecting the features formed by the hot spot on the overlying plate: the Monteregian Hills (Quebec, 125 Ma), the
White Mountains (New Hampshire, 115 Ma), and the Bear (100 Ma) and Nashville (83 Ma) seamounts offshore.
Monteregian
Hills
125
White
Mountains
115
New York City
Bear
Seamount
100
New England seamount chain
Nashville
Seamount
83
0 400
Kilometers
(d) Based on the ages of these features and on the distance the North American Plate moved, what was the average
rate of plate motion?
(cm/yr)
(e) Based on the rate you calculated in question (d) and the direction of plate movement shown by the red dashed
line, mark on the map where New York City will be located in 50 years.
(f) Generalizing from these calculations, what significant effect will plate motions have on human society in the next
50 years? In the next 1,000 years?
If there is any dispute about global warming, it is over how big a role humans are
playing in the process and what we can do to minimize our impact. Skeptics point
out correctly that it has been much warmer in the prehuman geologic past than it
is today, and some argue that humans can’t possibly have a large impact on such a
global-scale phenomenon. To examine this issue intelligently, we need to know what
controls the atmospheric temperature at the Earth’s surface, but before we begin, it
is critical to understand the difference between weather and climate.
18.2 CHANGES IN THE EARTH SYSTEM
477