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40 terms


Rift Valley
divergent plate boundary
both convergent plate & divergent plate boundary
ancient precursor of the Pacific Ocean
supercontinent 200 million years ago
depression along ridge axis
Rift Valley
study of changes in the character of oceans due to geographic changes
study of magnetism over geologic time
The relatively young age of the seafloor supports the idea that subduction must take place.
The magnetic north pole has remained very close to the geographic North Pole through all of geologic time
Paleomagnetism confirms that at particular times in the geologic past Earth has had more than one magnetic north pole.
New crust is formed at trenches and old crust is subducted at ridges
The oldest rocks are located at mid-ocean ridges.
Earthquakes are common along fracture zones.
Deep focus earthquakes are often associated with deep-sea trenches.
The magnetic field of the Earth reverses itself each time that magma erupts at a mid-ocean ridge.
Fast-moving spreading ridges tend to be more gently sloped that slow-moving ridges.
Deep-sea trenches are found at convergent plate boundaries
At divergent plate boundaries, only shallow focus earthquakes can be found
Fossils found in sediments can be used to:
a. indicate the relative age of the sediments.
b. provide evidence for plate movement.
c. suggest ancient climate characteristics.
d. support the idea that land masses were joined.
All continents fit together with the least number of overlaps and gaps when the continents are matched along
contours at around 2000 meters in depth
Fossils of ancient polar plants are currently found near the equator because the:
plants lived near the poles, but land masses have drifted to current locations
Climate distribution on Earth is primarily controlled by
All of the following provide evidence for continental drift
a. age of selected continental rocks.
b. apparent polar wandering.
c. location of coral reef fossils.
e. shape of continental margins.
Continental drift was confirmed through the use of the
location of alternating magnetic polarity of seafloor rocks
Which of the following statements best describes the relationship between Earth's geographic and magnetic poles?
The magnetic pole wobbles, but stays near the geographic pole.
Vine and Matthews determined that new ocean floor was being produced at ocean ridges by examining
the magnetic pattern on the seafloor.
Confirmation of seafloor spreading was supported by the:
age of seafloor
The seafloor magnetic pattern is be best described as:
parallel to and symmetric about ocean ridges.
Oceans become deeper moving away from ridges due to:
thermal contraction of hot asthenosphere.
Differences in height between continental crust and oceanic crust are explained by:
What is the asthenosphere composed of
outer mantle material
What is the lithosphere composed of
the crust and the topmost portion of the outer mantle
Moving from oceanic ridge to oceanic trench, the thickness of the lithosphere
increases in proportion to the distance
Deep ocean trenches are associated with
Subduction Zones
The Hawaiian Islands are located where the Pacific plate is
moving over a hot spot
The Mid-Atlantic Ridge is an example of a
divergent boundary.
Which of the following is associated with convergent plate boundaries on the seafloor
crest of the mid-ocean ridge
Which of the following is characteristic of oceanic-oceanic convergent plate boundaries?
volcanic island arcs
Which of the following is characteristic of oceanic-continental convergent plate boundaries?
andesitic volcanoes
measurement of ocean depth and seafloor