OCE CH 2
Paleomagnetism confirms that at particular times in the geologic past Earth has had more than one magnetic north pole.
False
The magnetic field of the Earth reverses itself each time that magma erupts at a mid-ocean ridge.
False
The magnetic north pole has remained very close to the geographic North Pole through all of geologic time
False
The oldest rocks are located at mid-ocean ridges.
False
depression along ridge axis
Rift Valley
Deep ocean trenches are associated with
Subduction Zones
Which of the following is characteristic of oceanic-continental convergent plate boundaries?
andesitic volcanoes
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
Which of the following is associated with convergent plate boundaries on the seafloor
crest of the mid-ocean ridge
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
supercontinent 200 million years ago
Pangea
ancient precursor of the Pacific Ocean
Panthalassa
Earthquakes are common along fracture zones.
False
New crust is formed at trenches and old crust is subducted at ridges
False
Climate distribution on Earth is primarily controlled by
Latitude
study of changes in the character of oceans due to geographic changes
Paleoceanography
study of magnetism over geologic time
Paleomagnetism
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.
The relatively young age of the seafloor supports the idea that subduction must take place.
True
At divergent plate boundaries, only shallow focus earthquakes can be found
True
Deep focus earthquakes are often associated with deep-sea trenches.
True
Deep-sea trenches are found at convergent plate boundaries
True
Fast-moving spreading ridges tend to be more gently sloped that slow-moving ridges.
True
All of the following provide evidence for continental drift
a. age of selected continental rocks. b. apparent polar wandering. 9 c. location of coral reef fossils. e. shape of continental margins.
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.
Confirmation of seafloor spreading was supported by the:
age of seafloor
Volcanoes
both convergent plate & divergent plate boundary
The Mid-Atlantic Ridge is an example of a
divergent boundary.
Rift Valley
divergent plate boundary
The Hawaiian Islands are located where the Pacific plate is
moving over a hot spot
Moving from oceanic ridge to oceanic trench, the thickness of the lithosphere
increases in proportion to the distance
Differences in height between continental crust and oceanic crust are explained by:
isostasy
Continental drift was confirmed through the use of the
location of alternating magnetic polarity of seafloor rocks
Bathymetry
measurement of ocean depth and seafloor
What is the asthenosphere composed of
outer mantle material
The seafloor magnetic pattern is be best described as:
parallel to and symmetric about ocean ridges.
What is the lithosphere composed of
the crust and the topmost portion of the outer mantle
Vine and Matthews determined that new ocean floor was being produced at ocean ridges by examining
the magnetic pattern on the seafloor.
Oceans become deeper moving away from ridges due to:
thermal contraction of hot asthenosphere.
Which of the following is characteristic of oceanic-oceanic convergent plate boundaries?
volcanic island arcs
