Question 1

The east coast of North America is a good example of a ________ tectonic margin.

Accepted Answer

The answer of The east coast of North America is...

Question 2

________ refers to the floatational balance achieved between the thickness and elevation of crustal or lithospheric rocks and that of the deeper mantle.

Accepted Answer

The answer of ________ refers to the floatational balance achieved...

Question 3

According to the Wilson Cycle, continents first break up by forming internal subduction zones that rift them apart and immediately reduce the size of their margins by subducting so much sediment.

Accepted Answer

The Wilson Cycle describes the breakup of continents initially through rifting caused by mantle plumes or other upwellings that thin the crust, leading to the formation of a new ocean basin, not through internal subduction zones. Subduction zones typically form at the edges of continents as oceanic plates are forced under continental plates, rather than causing the initial breakup.

Question 4

Overthickened crust continues to slowly rise, even though its thickness is gradually being reduced by erosion.

Accepted Answer

The statement is true. Even though the crust is being eroded, it is still slowly rising due to ongoing tectonic activity. This rise is caused by the movement of molten rock in the mantle beneath the crust, which exerts pressure and pushes the crust upward.

Question 5

The earliest and most primitive crust to form was probably oceanic.

Accepted Answer

The earliest known crust, which formed approximately 4 billion years ago, was likely made up of oceanic crust. Continental crust did not begin to form until later in Earth's history.

Question 6

The Wilson Cycle was deduced from studies of old, complex mountain chains like the Appalachians.

Accepted Answer

The Wilson Cycle was first proposed by J. Tuzo Wilson in 1966 after studying the evolution of old, complex mountain chains such as the Appalachians.

Question 7

Soft, easily-eroded strata high in a mountain range would suggest that the mountain building occurred long ago, geologically speaking, like that in the Appalachian region along the eastern margin of North America.

Accepted Answer

The answer of Soft, easily-eroded strata high in a mountain...

Question 8

What must happen to a region of crust for it to undergo a dramatic change in elevation?

Accepted Answer

The answer of What must happen to a region of...

Question 9

Mountain belts are, or were generally formed ________ plate boundaries.

Accepted Answer

The answer of Mountain belts are, or were generally formed...

Question 10

An ophiolite-complex terrane would contain abundant, rhyolitic, volcanic rocks, and sandstone.

Accepted Answer

An ophiolite complex is composed of oceanic crust and upper mantle materials that have been uplifted and emplaced onto continental crust through tectonic processes. It typically contains ultramafic rocks such as peridotite, gabbro, basalt, and sedimentary rocks such as chert and shale. Rhyolitic volcanic rocks and sandstone are not typically part of an ophiolite complex terrane.

Question 11

Most of the continents as we know them today had formed by 3.5 billion years ago.

Accepted Answer

This statement is false. Continental drift and plate tectonics have been ongoing processes for billions of years, and the shape and arrangement of the continents has changed significantly over time. By 3.5 billion years ago, the Earth's surface was still largely covered by oceans with only small landmasses and island arcs forming. It wasn't until about 2.5 billion years ago that the first stable continents began to emerge.

Question 12

As the Pleistocene ice sheets in Canada grew and thickened, the crust beneath the ice gradually subsided.

Accepted Answer

This phenomenon is known as isostatic depression, where the weight of the ice causes the crust to sink or subside. It is a well-documented process during the Pleistocene era.

Question 13

Ophiolites, like at Thetford Mines Quebec, can provide economic deposits of chrysotile asbestos.

Accepted Answer

Ophiolites are known to host chrysotile asbestos deposits, which can be economically important. Thetford Mines in Quebec is a well-known example of an ophiolite-hosted asbestos deposit. However, it should be noted that the use of asbestos is highly regulated or banned in many countries due to its health risks.

Question 14

What kind of a continental margin would have a staircase-like topographic profile downwards to thick accumulations of shallow water shelf sandstones?

Accepted Answer

The answer of What kind of a continental margin would...

Question 15

As thrusting builds up the elevation of a mountain belt, isostasy helps elevate the base of the crust at the same time.

Accepted Answer

The answer of As thrusting builds up the elevation of...

Question 16

The placement of hotter than average mantle weakens the mantle's ability to support the continental crust and the crust founders and sags down, reducing its regional elevation.

Accepted Answer

The answer of The placement of hotter than average mantle...

Question 17

The ________ continental mountain belts will have the thickest or lightest underlying crustal rocks.

Accepted Answer

The answer of The ________ continental mountain belts will have...

Question 18

Crustal collapse produces ________ valleys.

Accepted Answer

The answer of Crustal collapse produces ________ valleys....

Question 19

Ophiolite accretion occurs most frequently by incomplete rifting on passive margins.

Accepted Answer

Ophiolite accretion typically occurs through the process of oceanic crust being thrust onto a continental margin through subduction or obduction. This process is not typically associated with incomplete rifting on passive margins.

Question 20

Fault-block mountains occur in regions dominated by ________ faulting.

Accepted Answer

The answer of Fault-block mountains occur in regions dominated by...

Quiz 13: Mountain Building and Continental Frameworks