2B(Complete solutions)
"Survey the ocean floor relief in the two views of Figure 2A-1, especially from coasts to deeper
waters. Color coding denotes water depth, showing that as ocean depth ______ blue becomes
darker. (Land topography is also displayed, and as elevation increases, greens transition to tan
and then darker brow.)" correct answersincreases
"In the top image, find the feature in the center of the Atlantic Ocean. This is the Mid-Atlantic
Ridge. Based on the color coding, is the Mid-Atlantic Ridge deeper or shallower than the ocean
floor on either side?" correct answersIt is shallower
"How does the Mid-Atlantic Ridge compare to the surrounding landmasses, specifically Africa?"
correct answers"The feature mirrors the western coastline of Africa."
"The Mid-Atlantic Ridge features a deep, narrow central rift valley following a central axis.
Magma seeps upward along the rift and adheres to the edge of either side of the ridge. The new
material pushes each plate away from the central axis. What is happening at the oceanic ridge?"
correct answers"It is a location where new crust forms."
"In Figure 2A-2, the Mid-Atlantic Ridge has red arrows denoting the motion of each plate along
the boundary. The Mid-Atlantic Ridge is a ______ plate boundary." correct answers"divergent"
"Go to the enlarged Figure 2A-1 map from Link 2A-1 (click on the map and it will open in
another screen where you can zoom in and out). Center the map on South America's west coast.
The darkest blue reveals an oceanic trench. The trench is deepest off the ______ portion of South
America's western coast." correct answerscentral
"Refer to Figure 2A-2 and examine the direction of motion along the western margins of South
America, Central America, and the Aleutian Islands. What is the dominant type of plate
boundary that forms in this area?" correct answersconvergant
"What other evidence supports that North and South America, Europe, and Africa once were
connected?" correct answers"Similar jigsaw-like shapes"
"Locate Iceland on Figure 2A-2. What is the significance of the location of the island on the
boundary between the North American and Euroasian plates?" correct answersIt is an active area
of divergence
"Within the abutting plates along the Mid-Atlantic Ridge, the crust migrates away from the ridge
as new material is added. Therefore, westward toward the east coasts of Greenland and North
America, the age of the oceanic crust ______." correct answers"increases"