Question 1

A(n)________ convergent plate margin is associated with a volcanic island arc.

Accepted Answer

The Aleutian convergent plate margin is associated with a volcanic island arc, which is formed when an oceanic plate subducts beneath another oceanic plate or a continental plate. The Aleutian Islands in Alaska, USA are a prime example of a volcanic island arc formed at a convergent plate boundary. The Andean convergent plate margin is also associated with volcanic activity, but it is primarily located along the western edge of South America. The accretionary and collisional convergent plate margins do not typically result in volcanic island arcs.

Question 2

A(n)________ convergent plate margin is associated with an accretionary wedge.

Accepted Answer

Andean-type convergent plate margins are associated with an accretionary wedge, where oceanic crust is subducted beneath continental crust, leading to the accumulation of sediments and materials scraped off the subducting plate.

Question 3

The term ________ refers specifically to the collection of all geologic processes and tectonic events that are responsible for building mountain belts.

Accepted Answer

The term orogenesis specifically refers to the collection of all geologic processes and tectonic events that are responsible for building mountain belts. A is incorrect because erogenesis is not a commonly used term. C is incorrect because orthogneisses refers to a type of rock, not the processes that form mountain belts. D is incorrect because drifting is too broad and does not specifically pertain to mountain belt formation.

Question 4

A(n)________ plate margin commonly evolves from a divergent one.

Accepted Answer

A passive plate margin is a type of plate boundary where two plates move away from each other. As they move away, the space between them is progressively filled with new rock that's emerged from molten magma underneath the earth's crust. This results in the creation of new land or ocean plates. Therefore, a passive plate margin commonly evolves from a divergent one.

Question 5

Volcanism along a continental arc is dominated by the eruption of ________.

Accepted Answer

Continental arcs are created by the subduction of oceanic lithosphere beneath a continental plate. The magma generated from this subduction is typically andesitic in composition, which is why the eruptions along a continental arc are dominated by andesitic lavas and pyroclastic materials. Basaltic lavas are generally associated with mid-ocean spreading ridges, while rhyolitic materials are more commonly found in continental rift zones. Ophiolites are remnants of oceanic crust that have been emplaced onto a continent through tectonic processes and are not directly related to volcanic activity.

Question 6

Since the early Mesozoic, the ________ has been passive tectonically.

Accepted Answer

The statement mentions "the early Mesozoic," which refers to the time period from about 252 to 66 million years ago. During this time, the eastern margin of North America was indeed passive tectonically, meaning there was no significant geologic activity such as mountain building or volcanic eruptions. The other choices, western margin of North America, western margin of South America, and southern margin of Eurasia, all experienced significant tectonic activity during this time period.

Question 7

Mountain belts formed from folded marine sediments by continent-continent collision, include ________.

Accepted Answer

These are the classic examples of mountain belts formed by continent-continent collision and are composed of folded marine sediments. The European Alps were also formed in a similar manner, but they were initially formed from the collision of Africa and Europe and were later modified by the collision of the Indian subcontinent. The East African rift is a divergent plate boundary, not a convergent one, and the NE edge of the Indian Ocean is a passive margin, not an active one.

Question 8

Mountainous relief is due to the rotation and sinking of lithospheric blocks in a ________ tectonic setting.

Accepted Answer

Mountainous relief in an extensional tectonic setting is typically associated with the stretching and thinning of the Earth's crust, which can lead to the formation of rift valleys and block mountains. This occurs as the lithosphere is pulled apart, causing blocks of crust to tilt, rotate, and sometimes sink, forming mountainous terrain.

Question 9

Which of the following geologic products or processes is not a result of mountain building?

Accepted Answer

Sedimentary basins in the middle of continental cratons are typically not a direct result of mountain building. They are often formed by other processes, such as the gradual subsidence of the crust due to its cooling and thinning over geological time, rather than the tectonic forces associated with mountain building.

Question 10

The concept of ________ includes the idea that crustal rocks are floating in a kind of gravitational balance and that their elevation depends on their density contrast to the underlying upper mantle.

Accepted Answer

The concept described is that of isostasy, which refers to the gravitational equilibrium between Earth's crust and its underlying mantle. Isostatic balance means that areas of higher elevation have a lower density in order to "float" atop the denser material beneath, while areas of lower elevation have a higher density.

Question 11

Rift valleys with mafic volcanics are ________ margins.

Accepted Answer

Rift valleys are formed due to extensional forces where the lithosphere is being pulled apart. Mafic volcanics are common in these areas due to the presence of mantle material, and the volcanic activity is a result of melting that occurs as the lithosphere thins and stretches. This type of margin is not associated with convergent plate boundaries (continent-continent, continent-ocean, or ocean-ocean) where volcanism is typically felsic in composition.

Question 12

Subduction zones include all of the following except for ________.

Accepted Answer

Subduction zones typically include deep ocean trenches, magma generation, and volcanic arcs. Suture zones are zones where two continental plates have collided and fused together, and are not typically associated with subduction zones.

Question 13

Subduction ceases in a(n)________ type of convergent plate margin.

Accepted Answer

Subduction typically ceases in a continent-continent convergent plate margin because the two continental plates are too buoyant to be forced beneath one another. Instead, they collide and buckle, forming mountains.

Question 14

Rugged elevations are due to crustal extension, related to underlying mantle heat or convective upwelling, in the ________.

Accepted Answer

The East African rift is a prime example of rugged elevations due to crustal extension, which is related to underlying mantle heat or convective upwelling. This geological process is responsible for the formation of the Great Rift Valley, the highest peak in Africa, and many other prominent geological features in the region. The other choices are also associated with rugged elevations, but they have different geological origins. The European Alps, for example, are the result of plate tectonics and collision between the African and Eurasian plates. The Appalachians and Caledonians are the remnants of ancient mountain ranges that have been eroded over time. The NE edge of the Indian Ocean is a tectonic boundary between the Indian and African plates, but it is not typically associated with rugged elevations.

Question 15

Which mountain belt did not have a stage of continent-continent collision as it formed?

Accepted Answer

The Andes mountain belt was formed due to a subduction zone where the South American Plate was overridden by the Nazca Plate, and there was no continent-continent collision involved in its formation. The Appalachian Mountains, Himalayas, and Urals all formed due to continent-continent collision.

Question 16

The world's highest mountain belts result from ________ convergent plate margins.

Accepted Answer

Continent-continent convergent plate margins result in the world's highest mountain belts. When two continental plates collide, neither plate is subducted because they are too light and buoyant, so instead they crumple and are forced upwards, creating mountain ranges such as the Himalayas.

Question 17

A good example of a present-day, passive, trailing, continental margin is the ________.

Accepted Answer

The west coast of Africa is a good example of a present-day, passive, trailing, continental margin. Passive margins are found along the edges of continents where there is no significant tectonic activity, such as plate boundaries or volcanic activity. They are characterized by a broad continental shelf, slope, and rise formed by sedimentation. The west coast of Africa fits this description, contrasting with active margins found at convergent or divergent plate boundaries.

Question 18

Topographically high-standing, mountainous areas generally ________.

Accepted Answer

Topographically high-standing, mountainous areas are generally composed of thick layers of lower density, crustal rocks that have been uplifted or pushed upward by tectonic forces. This is why these areas stand out above the surrounding landscape.

Question 19

As new layers of sedimentary or volcanic rock are added to the crust the ________.

Accepted Answer

As new layers of sedimentary or volcanic rock are added to the crust, the thickness increases faster than the elevation because the weight of the new rocks causes them to compress and settle, resulting in little to no increase in elevation.

Question 20

Mountain belts formed in several stages by the opening and closing of the Iapetus Ocean in the Paleozoic, include the ________.

Accepted Answer

The Appalachian Mountains in North America and the Caledonian Mountains in Europe were both formed by the opening and closing of the Iapetus Ocean during the Paleozoic era. The European Alps were formed by the collision of the African and Eurasian plates in the Cenozoic era, not related to the Iapetus Ocean. The East African rift and NE edge of Indian Ocean are both regions of active tectonic activity and not specifically related to the Iapetus Ocean.

Quiz 13: Mountain Building and Continental Frameworks

A(n) ________ convergent plate margin is associated with a volcanic island arc.

A(n) ________ convergent plate margin is associated with an accretionary wedge.