oceanography chapter 2

supercontinent 250 million years ago
study of magnetism over geologic time
island arc
subduction zone
seafloor magnetic stripes
spreading center
subduction zone
Evidence for continental drift includes
-past glacial activity
-the distribution of organisms
-matching sequences of rocks and mountain chains
-the fit of the continents
Fossils of ancient polar plants are currently found near the equator because the
plants lived near the poles, but landmasses have drifted to current locations
Climate distribution on Earth is primarily controlled by
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Regarding glacial ages, why is it unlikely that the entire world was covered by ice 300 million years ago
Coal deposits from the same geologic age are now present in North America and Europe, which formed from the remains of vast tropical swamp plants
Earthquakes can occur only in the
The book The History of Ocean Basins, which contained the idea of seafloor spreading, was written by geologist
Harry Hess
The seafloor magnetic pattern is best described as
parallel to and symmetric about mid-ocean ridges
Tectonic plates are pieces of the ________ that float on the more fluid ________ below
lithosphere; asthenosphere
Describe Earth’s magnetic field, including how it has changed through time
Earth’s magnetic field is composed of invisible lines of magnetic force that originate within Earth and travel out into space. The polarity of the field has reversed itself throughout geologic time
Describe seafloor spreading and why it was an important piece of evidence in support of plate tectonics
Captain Hess suggested that new ocean crust was created at the mid-oceanic ridges and disappeared back into deep Earth at the trenches near the edges of ocean basins. This was an important piece of evidence in support of plate tectonics because it provided a mechanism for continental and oceanic plate motion
The Mid-Atlantic Ridge is an example of a
divergent plate boundary
Which of the following is characteristic of oceanic-continental convergent plate boundaries
andesitic volcanoes
Which of the following is characteristic of continental-continental convergent plate boundaries
uplifted mountain ranges
hot spot
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hydrothermal vents
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Mariana Trench
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Do most lithospheric plates contain both oceanic- and continental-type crust
Yes, most lithospheric plates contain both oceanic- and continental-type crust
Iceland is located on what type of plate boundary
The Hawaiian Islands are located where the Pacific plate is
moving over a hot spot or mantle plume
volcanoes on the seafloor that are flat-topped because of wave erosion are called
The first scientist to propose the origin of coral reefs based upon subsidence (sinking) of volcanic islands was
Charles Darwin
Aleutian Islands
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How is the age distribution pattern of the Hawaiian Islands-Emperor Seamount chain explained by the position of the Hawaiian hot spot
The volcanoes in the Hawaiian Island-Emperor Seamount chain get progressively older as one heads northwestward from Hawaii. These age relationships suggest that the Pacific Plate has been steadily moving northwestward, while the underlying mantle plume has remained relatively stationary
How can plate tectonics be used to help explain the difference between a seamount and a tablemount
A seamount is a volcano with a cone-shaped top, whereas a tablemount is a volcano with a flattened top. Though both of these features originate at the crest (and topographic high) of the mid-ocean ridge, a tablemount has been subject to wave erosion when it rises above sea level. When the crust containing the tablemount is pushed away from the crest (and therefore onto a topographically lower position), or is moved away from a hot spot, it is re-submerged with its flat top
The study of historical changes of continental shapes and positions is called
Loihi is
the newest Hawaiian volcano
The cities of Los Angeles and San Francisco, CA, are about 380 miles apart. Plate motion along the San Andreas Fault is about five centimeters per year. If the Los Angeles Dodgers and the San Francisco Giants continue to play at their current locations, how long will it be before their games will constitute a cross-town rivalry
About 12,230,000 years
A researcher interested in the vertical zonation of oceanic lithosphere would want to study
Earth’s magnetic field
-The locations of Earth’s magnetic poles have moved through time and have even reversed in polarity
ocean crust
-Ocean crust is destroyed at deep sea trenches
What do all plate boundaries have in common
They are all associated with zones of earthquakes
nemataths and volcanic arcs
-Nemataths and volcanic arcs are both the result of volcanic activity