Geo Test 1
Durning a journey to the center of the earth, one would experience temperatures ____.
A.) and pressure both increasing.
Under the theory of plate tectonics, the plates themselves are ____.
A.) discrete pieces of lithosphere at the surface of the solid Earth that move with respect to one another
Seafloor spreading occurs at ____ boundaries.
A.) divergent
With increasing distance from a mid-ocean ridge, the age of oceanic crust _____.
A.) increases
The process of differentiation early in the protoplanet's history causes formation of the protoplanet's ____.
A.) metallic core
Marine magnetic anomalies can be used to estimate the ____.
A.) rate of seafloor spreading
Slab pull occurs because subducting slabs are
B.) cooler, and therefore more dense, than surrounding asthenosphere
The Earth's magnetic field is a ____.
B.) dipole, such as that produced by a bar magnet
Transform boundaries occur most frequently along ____ boundaries in order to break the ____ into segments so as to accommodate motion on a sphere.
B.) divergent; mid-ocean ridges
Regions of the sea floor with positive magnetic anomalies were formed durning times when Earths magnetic field _____.
B.) had normal polarity
Wegener's idea of continental drift was rejected by geologists because ____.
B.) he could not conceive of a valid mechanism that would cause continents to shift positions.
At a subduction zone, the down-going (subducting) plate ____.
B.) is always composed of oceanic lithosphere
Terrestrial planets are mainly composed of ____ while Jovian planets are made dominantly of ____.
B.) rocks and metals; volatiles
The rate of seafloor spreading exactly matches the rate of ___.
B.) subduction
The Jovian planets are ____.
C.) Jupiter, Saturn, Uranus, and Neptune
The discovery of seafloor spreading finally provided a mechanism for ____.
C.) continental drift
Atoms that are heavier than iron are generally produced by ___.
C.) explosions of supernovas
Which of the following was NOT used as evidence for seafloor spreading?
C.) jigsaw puzzle fit of the continents
In the geological past, the polarity of Earths magnetic field is ___.
C.) known to have experienced numerous reversals, as shown by remnant magnetization of iron-rich minerals in rocks
According to the figure below, marine magnetic anomalies lay roughly ____ to mid-ocean ridges.
C.) parallel
Continental coastlines that occur within the interior of a tectonic plate are called ____ margins.
C.) passive
Deformed (bent, stretched, or cracked) lithosphere occurs
C.) primarily on the margins of tectonic plates
Which of the following statements about Earth's core is FALSE?
D.) by volume, it is largest compositional layer of Earth.
Seafloor spreading _____.
D.) creates new oceanic crust
The lithosphere is composed of the ____.
D.) crust and the uppermost part of the mantle.
In Wegener's evidence for continental drift, continents were proposed to fit together, such as the east coast of South America with the ____.
D.) lower west coast of Africa
The theory of ___ states that the lithosphere is broken into a series of plates that move relative to each other.
D.) plate tectonics
The apparent tendency of the north (or south) magnetic pole to vary in position over time is termed _____.
D.) polar wondering
What would happen if the rate of seafloor spreading was faster than the rate of subduction?
D.) the earth would grow larger
Younger oceanic crust will have ____ ocean sediments, while older oceanic crust will have ___ oceanic sediments.
D.) thinner; thicker
According to the Expanding Universe theory, our universe is contracting.
F
Continental drift is the hypothesis that the sea floor forms at the crest of the mid-oceanic ridge, then moves horizontally away from the ridge crest.
F
Hawaii is an example of a volcanic island arc formed by subduction.
F
Hot spots can occur only within continental plates.
F
Our sun belongs to a galaxy known as Andromeda.
F
The distribution of volcanoes across the globe provides the primary indicator of bounties between all tectonic plates.
F
The lithosphere lies directly above the crust.
F
The mid-ocean ridges are elevated above the surrounding sea floor because the lithosphere is thickest at the ridges so they stand up taller.
F
The rate of sea floor spreading averages about one meter (3 feet) per year.
F
The sea floor is older than the earth.
F
The thickness of the crust is about the same as the thickness of the mantle.
F
Unlike the lithosphere, the asthenosphere has a density similar to the core.
F
As a descending plate reaches depths of 100 to 150 km, magma is generated in the overlying mantle wedge.
T
At transform plate boundaries, earthquakes are common but volcanoes are absent.
T
Beneath a blanket of sediments, oceanic crust is primarily composed of basalt.
T
Compared to typical oceanic crust, the thickness of continental crust is greater.
T
Continental coastlines that occur along the margin of a tectonic plate are called active continental margins.
T
Continental crust is less dense than oceanic crust.
T
Geomagnetic reversals represent a source of information on the rate of sea-floor spreading.
T
In the heliocentric model, earth orbits around the sun.
T
The Himalayan Mountains were produced by a collision of India with Asia.
T
The best estimate of when the universe formed is 13.8 Ga.
T
The current estimate for the age of Earth is 4.57 Ga.
T
The discovery of sea floor spreading finally provided a mechanism for continental drift.
T
The distinction between the crust and the mantle is primarily on the basis of a difference in composition.
T
The earth consists of shells or spheres composed of materials having different properties.
T
The eruption of Mount St. Helens was associated with activity along a convergent plate boundary.
T
The portion of a fracture zone between two offset portions of a ridge crest is called a transform fault.
T
The sun was created at the center of the accretionary disk when the temperature became high enough for fusion to occur.
T
Wegener's theory of continental drift proposed that the continents plowed through oceanic crust.
T
