geology exam 1- first 52 questions
The Wadati-Benioff zone extends down within the mantle to a maximum depth of ________.
660 km
The oceanic lithosphere is typically coated in a layer of sediment. Which of the following is NOT true about this sediment?
All of the sediment is eventually subducted along with the lithosphere into the mantle.
In a hot-spot volcanic island chain, such as the Hawaiian Islands, which of the following is NOT true?
All volcanoes in the chain can be simultaneously active.
At a subduction zone, the downgoing (subducting) plate ________.
At a subduction zone, the downgoing (subducting) plate ________.
The image below shows a view of a typical segmented mid-ocean ridge. Which letter below marks the location of the active transform fault?
B
Which of the following statements is true concerning rock produced at mid-ocean ridges?
Basalt is produced at shallow depths and gabbro at deeper depths.
Which of the following is NOT true about Earth's tectonic plates?
Some tectonic plates contain only continental lithosphere.
________ is an example of a continental rift and the ________ is/are the result of collision.
The Basin and Range Province; Himalayan Mountains
The image below shows a cross-sectional view of a typical subduction zone, with earthquake locations shown with small dots. The band of earthquakes that follows the shape of the downgoing plate is termed the ________.
Wadati-Benioff zone
In the scope of plate tectonics, an active margin is defined as ________.
a continental coastline that coincides with a plate boundary
Earthquakes occur most frequently near ________ margins.
active
The youngest sea floor is typically found ________.
along mid-ocean ridges
A guyot is ________.
an extinct oceanic hot-spot volcano that has subsided below sea level
When two plates composed of continental lithosphere are pulled together at a convergent boundary, the result is ________.
collision and mountain formation
Large, thick-crusted, nonvolcanic mountain belts, like the Himalayas, are associated with ________.
continent-continent collisions
Deep-oceanic trenches are features of ________ plate boundaries.
convergent
Subduction zones are found at which basic plate boundary type?
convergent
The lithosphere of the Earth is generally thickest at and near ________ plate boundaries. a. divergent c. transvergent
convergent
Which basic type of plate boundary is shown in the image below?
convergent
The volcanoes of the Cascades Mountains in the northwest United States are related to melting of rock associated with a ________.
convergent plate boundary
Under the theory of plate tectonics, the plates themselves are ________.
discrete pieces of lithosphere at the surface of the solid Earth that move with respect to one another
Iceland is one of the few places in the world that is both above sea level and situated atop a ________ plate boundary.
divergent
The lithosphere of the Earth is generally thinnest at ________ plate boundaries.
divergent
Which basic type of plate boundary is shown in the image below?
divergent
Mid-ocean ridges are segmented and contain which two basic types of plate boundaries linked together?
divergent and transform
The distribution of ________ across the globe provides the primary indicator of boundaries between all tectonic plates.
earthquakes
At transform plate boundaries, ________.
earthquakes are common but volcanoes are absent
Summed over the entire surface of Earth, the rate of spreading at divergent boundaries is ________ lithospheric consumption at subduction zones.
equal to
Compared to typical oceanic lithosphere, the thickness of continental lithosphere is________.
greater
According to the model proposed by geophysicist J. Tuzo Wilson, hot spots are caused by ________.
hot plumes of mantle material that rise up through cooler, denser surrounding rock
Consult the figure below. Hawaii is an example of ________.
hot-spot volcanism
The theory of plate tectonics ________.
incorporates and explains both seafloor spreading and continental drift
Unlike the lithosphere, the asthenosphere ________.
is able to flow over long periods of time
Continental lithosphere ________.
is thicker than oceanic lithosphere
The lithosphere of Earth will not flow because it ________.
is too cool
The thickness of oceanic lithosphere is ________.
least near the mid-ocean ridges and thickens away from the ridges
At a subduction zone, the overriding plate ________.
may be composed of either oceanic or continental lithosphere
A volcanic island arc forms when ________.
oceanic lithosphere subducts beneath another oceanic lithospheric plate
Continental coastlines that occur within the interior of a tectonic plate are called ________ margins.
passive
Broad, sediment-covered continental shelves are found along ________.
passive margins
Hot-spot tracks result from moving ________.
plates
Deformed (bent, stretched, or cracked) lithosphere occurs ________.
primarily on the margins of tectonic plates
The mid-ocean ridges are elevated above the surrounding sea floor because ________.
ridge rocks are hot and therefore have relatively low density
On either side of a mid-ocean ridge, the lithosphere begins to ________.
sink because it cools and contracts
The primary difference between lithospheric and asthenospheric mantle that gives rise to numerous different patterns of physical behavior is ________.
temperature: the lithosphere is cooler than the asthenosphere
Oceanic lithosphere thickens away from the mid-ocean ridge primarily due to ________.
the addition of new lithospheric mantle as a result of cooling
A triple junction, like the one shown below, is a place on Earth's surface where ________.
the boundaries of three lithospheric plates meet at a single point
According to Archimedes' principle of buoyancy, an iceberg sinks until ________.
the total mass of the water displaced equals the total mass of the whole iceberg
The San Andreas Fault zone in California is an example of a ________ plate boundary.
transform
Which basic type of plate boundary is shown in the image below?
transform
Segments of mid-ocean ridge systems are offset. Between the offset segments we observe ________.
transform faults
Hot spots can occur ________.
within either continental or oceanic plates
