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GEOL 101: EXAM 1
Principles Of Geology |
Core, Mantle, Crust |
Core, Mantle, Crust |
It is lower density than the mantle |
The radius of the Earth's core is 3486 km and the thickness of the mantle, which surrounds the core, is 2900 km. Therefore, the volume of the mantle is ____ the volume of the core. |
Much more than. |
Much more than. |
Continental Crust |
The ___ forms the relatively cool, brittle plates of plate tectonics. |
Lithosphere. |
Which one of the following best characterizes the asthenosphere? |
A zone of softened peridotite and magma in the upper mantle. |
Which of the following best describes the hypothesis of seafloor spreading? |
Rising material in the mantle spreads laterally, carrying the seafloor away from seafloor ridges in the center of the ocean basin. |
Which of the following energy sources is thought to drive the lateral motions of Earth's lithospheric plates? |
Export of heat from deep in the mantle to the top of the asthenosphere. |
Why is so much basaltic magma erupted along mid-ocean ridges? |
Lowered pressures decrease the temperatures at which basalt magma can partially melt from a rising plume of mantle peridotite. |
'Black smokers’ in the ocean are: |
Submarine hot springs on mid-ocean ridges |
Cooler, older, oceanic lithosphere sinks into the mantle at: |
Subduction zones along convergent plate boundaries. |
The Hawaiian Islands become younger to the east-southeast (Hawaii is the youngest, while the seamounts to the west-northwest are oldest). Assuming the hot spot is stationary, and the entire chain of islands was formed by this hot spot, which direction is the Pacific plate moving? |
West-northwest |
A hot spot of long term active volcanism is: |
The Earth surface location of a large mantle plume |
Oceanic ridges are elevated compared to the surrounding
ocean floor because __________.
|
Newly formed lithosphere is hotter and therefore less dense than the surrounding rocks and occupies more space |
Which technique for calculating when the Earth formed as a planet is the most accurate in determining a numerical age for the Earth? |
Analysis and measurement of the ratios of uranium and lead isotopes present in rocks. |
Which of the following geologic observations would indicate that a sandstone is younger than a granite? |
An unconformity surface between the granite and sandstone |
Which of the following best defines a mineral and a rock? |
In a mineral the constituent atoms are bonded in a regular, repetitive, internal structure; a rock is a lithified or consolidated aggregate of different mineral grains. |
Atoms of an element with an electrical charge are ____ and atoms of an element with different number of neutrons in the nucleus are ____ . |
ions; isotopes |
The difference between ionic and covalent bonds is _______. |
Ionic bonds are when atoms are attracted electrostatically due to positive and negative charges; covalent bonds are when atoms share the same electron(s) |
A sheet silicate mineral, with silica tetrahedra ions arranged in sheets will usually: |
Have good cleavage along the sheets |
The feldspars are an example of a mineral group with: |
3-dimensional array of silica tetrahedra. |
A mineral composed of iron (Fe) and oxygen would be: |
An ore mineral for iron |
A mineral is considered a gemstone if it: |
Has good color, reflects light well, is rare. |
Why do magmas rise toward Earth's surface? |
Magmas are mainly liquid and contain dissolved fluids such as water; most are less dense than the adjacent solid rock. |
How is magma produced from rising mantle rock along midocean ridges? |
Temperatures remain high as lowered pressures decrease melting temperatures. |
Which of the following describes best the difference between magma and lava? |
Upon eruption, magma becomes lava, the magma that flows out of the volcano |
Lava flows are typically finer grained than intrusive igneous rocks. Why? |
The extrusive magma cools quickly so the mineral grains do not have time to grow. |
Composite cone, high slope angle-volcanoes are characteristic of : |
Subduction zone andesitic volcanoes. |
Which of the following rocks is likely to have the most quartz within it and why? |
Granite; intrusive rock that formed from cooling of relatively high silica magma. |
Which one of the following shows the correct order of decreasing magma viscosity and silica content of magma (high viscosity on left, low viscosity on right)? |
rhyolite, andesite, basalt |
What is a difference between a caldera and a crater? |
A caldera is a large depression caused by collapse after a large-scale eruption, whereas a crater is a small, steepsided, volcanic depression bored out by an eruptive event.
|
Which one of the following most accurately describes the volcanoes of the Hawaiian Islands? |
Shield volcanoes fed by a long-lived hot spot below the Pacific lithospheric plate. |
Which one of the following is a natural disaster? |
A landslide striking San Francisco. Not a hurricane, volcano, or earthquake. |
The principle of ___ states that the physical, chemical, and biological processes at work shaping the Earth today have also operated in the geologic past. |
Uniformitarianism |
What is the accepted age of the Earth? |
4.56 billion years |
___ was an important 18th century scientist who developed the idea of Uniformitarianism to explain the slow, steady changes responsible for shaping the Earth. |
James Hutton |
What percentage of the Earth is covered by oceans? |
71% |
What percentage of the Earth is covered by oceans? |
Energy exchanges b/w the surface and outer space, creating weather and climate. Protection from ultraviolet radiation and the intensity of the Sun. Providing air for respiratory processes in the biosphere. |
Which of the four spheres of Earth is the most extensive? |
Geosphere |
What is the date of the formation of the universe? |
13.7 billion years ago. |
What is the definition of differentiation? |
Separation of materials based on density. |
What property of the crust allowed it to form as the exterior of the Earth? |
Materials that make up the crust are less dense and rose to the top.
|
What provides us with the most information about the interior of the Earth? |
Seismic energy waves |
If the temperature in the Earth generally increases with depth, how is it possible that the Inner Core is a solid?
|
The pressures in the core are immense and keep it in a solid state in spite of the temperature.
|
Which layer of the Earth is the thinnest? |
Crust |
Which layer of the Earth is the thickest? |
Mantle |
What is the definition of the asthenosphere? |
A soft, low-velocity layer in the Upper Mantle. |
The ___ is a layer of liquid nickel and iron believed to be responsible for generating the Earth's magnetic field. |
Outer Core |
A ___ is a part of the craton that is covered by a thin veneer of sedimentary rocks. |
Platform |
In what two areas are the youngest mountain ranges found today? |
The Circum-Pacific belt and Southern Europe/Asia |
Historical geology describes geological processes that operate on the Earth. |
FALSE. |
Geologic hazards are natural processes. |
TRUE. Natural hazards result from natural Earth processes. |
Before a hypothesis can become an accepted part of scientific knowledge, it must pass objective testing and analysis. |
TRUE. |
A hypothesis can never be changed or modified. |
FALSE |
The majority of the hydrosphere is found in the atmosphere in the form of water vapor. |
FALSE |
The four spheres on Earth operate independently from each other. |
FALSE. The 4 major systems of Earth are the geosphere, hydrosphere, atmosphere, and biosphere. |
Both energy and matter will flow in and out of an open system. |
TRUE |
The interior of the Earth is divided into roughly spherical layers separated by density. |
TRUE. Earth formed from the accumulation of dust and gas, and multiple collisions of smaller planetary bodies. |
The lithosphere is the layer in the interior of the Earth that is just below the crust. |
FALSE |
External processes driven by solar energy can create the materials necessary for sedimentary rocks. |
FALSE |
The craton is the interior of a continental mass that has been undisturbed for the last 1 billion years. |
FALSE |
___ is the doctrine that describes how the Earth was shaped by a series of great catastrophes over a short period of time. |
Catastrophism |
What was the source for the early atmosphere? |
Differentiation of materials in the early Earth and the process of degassing led to the early atmosphere. |
Earth's spheres |
Hydrosphere - water portion
Biosphere - all life on Earth
Atmosphere - gaseous envelope around the planet
Geosphere - the solid earth |
Events leading up to the formation of the early Earth in order. |
1. Rapid expansion of stellar matter
2. Formation of solar nebula
3. Nuclear fission lights up Sun
4. Formation of proto-planets |
Igneous Rocks |
Rocks that form from the crystallization of molten material. Examples: Granite, Gabbro, Rhyolite, Basalt |
Sedimentary Rocks |
Rocks that form from pre-existing materials going through lithification. Examples: Limestone, Conglomerate, Arkose, Dolomite |
Metamorphic Rocks |
Rocks that form when a pre-existing rock is altered due to heat and pressure. Examples: Slate, Schist, Quartzite, Phyllite |
Which scientist developed the idea of Continental Drift? |
Alfred Wegener. He also proposed the super-continent Pangaea. |
Although the jigsaw-puzzle fit of the southern continents was noted, opponents of Continental Drift argued that, even if continental displacement had occurred, a good fit between the continents today would be unlikely. What geological evidence did they cite to support this claim? |
Wave erosion and coastal deposition have changed the shape of the continents |
When the continents were assembled and mountain ranges were matched up, mountains in Scandinavia and the British Isles matched up perfectly with which North American mountain range? |
Appalachian Mountains |
The lithosphere is composed of material from the ________ and the rigid part of the ________. |
Crust; Upper Mantle |
Which plate boundary accounts for the smallest percentage of all plate boundaries on the surface of the Earth? |
Transform Boundaries |
Continental crust is mainly composed of ________ whereas oceanic crust is mainly composed of ________. |
Granite; Basalt |
Why are the mid-ocean ridges higher in elevation than the surrounding ocean floor? |
Warmer material near the ridge is less dense, so floats higher on the mantle |
At a ________, one colliding plate will be forced beneath another because of differences in density. |
Subduction Zone |
How will the age and temperature of the subducting plate affect its angle of descent? |
Younger and warmer plates will have a shallow angle of descent |
A ________ is a geographic low marking the location where oceanic lithosphere descends into the mantle. |
Deep-Ocean Trench |
Which type of convergence will result in a continental volcanic arc? |
Oceanic-Continental |
Which type of convergence will result in a volcanic island arc? |
Oceanic-Oceanic |
Where are the majority of transform faults located? |
On the ocean floor offsetting segments of oceanic ridge |
What is a mantle plume? |
An upwelling of hot material from the Earth's interior that is cylindrical in shape |
________ is when iron particles in lavas align their magnetic fields with magnetic north, preserving a record of that pole's location at that moment in time. |
Paleomagnetism |
Where is the top of the asthenosphere is closest to Earth's surface? |
Along a mid-ocean ridge |
What two pieces of information would researchers need to have in order to calculate the rate of plate motion for seafloor spreading? |
Distance from the rift and age of seafloor sample |
How can the orientation of transform faults provide information about the direction of plate motion? |
Transform faults are parallel to the direction of plate motion |
What generates the heat necessary for convection in the Earth? |
Decay of radioactive materials |
________ is when cold oceanic lithosphere are more dense than the underlying warm lithosphere. |
Slab Pull |
In which layer of the Earth does the convection necessary for plate motion occur? |
Outer Core |
The majority of divergent plate boundaries are associated with oceanic ridges. |
TRUE |
An oceanic plate that has been permeated by water before subduction will melt at a lower temperature than a "dry" oceanic plate. |
TRUE |
Which is denser: Oceanic lithosphere or continental lithosphere? |
Oceanic lithosphere |
Analyze and explain how the respective temperatures of the lithosphere and asthenosphere affect those layers' rigidities and responses when force is applied. |
The lithosphere is cooler and more rigid, so will bend or break when force is applied. The asthenosphere is warmer and more pliable, so will flow when force it applied. |
_______ is the name of the process by which new seafloor is generated at mid-ocean ridges. |
Seafloor Spreading |
Tectonic boundary |
Convergent - crust is being destroyed (compression affecting it)
Divergent - crust is being created (tension affecting it)
Transform - crust is being conserved (shear affecting it) |