Question 1

A fault-bounded body of rock that has a different geologic history than adjacent regions is called a:

Accepted Answer

A tectonic terrane is a fragment of crustal material formed on, or broken off from, one tectonic plate and accreted or sutured to crust lying on another plate. The concept is crucial in the study of geological history because it explains the presence of distinct and unrelated geologic histories side by side.

Question 2

Which feature on this figure formed during the time when these two terranes joined?

Accepted Answer

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Question 3

Which of the following is NOT the name of a supercontinent?

Accepted Answer

Tethys is not the name of a supercontinent; it refers to an ancient ocean that existed between the continents of Gondwana and Laurasia before the formation of the Mediterranean Sea.

Question 4

Which of the following is used to match continents or track positions of the continents in the past?

Accepted Answer

All of these methods (reconstructions of seafloor spreading, rock types and structures, and magnetism stored in rocks) are used to match continents or track the positions of the continents in the past.

Question 5

Which feature on this figure formed after the two terranes were already joined?

Accepted Answer

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Question 6

Numerous terranes exist in Alaska. One of these is the Wrangellia terrane. Why is the Wrangellia terrane considered part of the same terrane as that from pieces scattered from western Idaho northward to Alaska?

Accepted Answer

The Wrangellia terrane and other pieces scattered from western Idaho northward to Alaska are considered part of the same terrane because they share similar ages and sequences of rocks. This geological similarity suggests that they were once part of the same landmass or formed under similar conditions before being dispersed to their current locations.

Question 7

Where was North America 150 million years ago?

Accepted Answer

150 million years ago, during the late Jurassic period, the continents were arranged differently than they are today due to the movement of tectonic plates. North America was indeed closer to Africa and South America as part of the supercontinent Pangaea before it began to break apart.

Question 8

Where was India located during most of the Mesozoic?

Accepted Answer

During the Mesozoic era, India was indeed located in the Southern Hemisphere, connected with Africa and Antarctica, and was part of the supercontinent of Gondwana.

Question 9

Which parts of North America have NOT been added to the continent since the Precambrian?

Accepted Answer

The Canadian Shield is the only part of North America that has not been added to the continent since the Precambrian. It is the ancient geological core of the North American continent, formed during the Precambrian era.

Question 10

What is the main reason why the age of oldest rocks can vary from one part of a continent to another?

Accepted Answer

The main reason for the variation in the age of the oldest rocks from one part of a continent to another is due to the accretion of tectonic terranes. This process involves pieces of the Earth's crust (terrains) being added to a continent at convergent plate boundaries, leading to a mosaic of rocks of different ages across the continent.

Question 11

Which numbered area on this geologic map of North America consists of recently added tectonic terranes?

Accepted Answer

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Question 12

Which of the following is a characteristic of a terrane?

Accepted Answer

Terranes are distinct geological entities or fragments of crust that have been attached to a continent along a fault or shear zone. Their boundaries are often defined by major faults or shear zones, distinguishing them from the surrounding geological formations. They do not necessarily have the same sequence of rocks or match in layers and fossils with adjacent areas, which is part of what makes them identifiable as separate entities.

Question 13

What part of North America contains the oldest exposed rocks?

Accepted Answer

The Canadian Shield is known for having the oldest exposed rocks in North America, some of which are over 4 billion years old. This vast area of ancient crystalline rocks forms the core of the North American continent.

Question 14

Which of the following is NOT a common setting in which a terrane originally forms?

Accepted Answer

Terranes can originate in a variety of geological settings, including oceanic plateaus, island arcs, oceanic crust, and linear island chains. These are all common environments where terranes, which are fragments of crustal material formed on, or broken off from one tectonic plate, and accreted or sutured to crust lying on another plate, can originate.

Question 15

Which of the following does NOT indicate that two terranes were already in contact by a certain time?

Accepted Answer

The presence of fossils of the same age from different environments in two terranes does not necessarily indicate that the terranes were in contact; it could simply mean that similar life forms existed in both areas at the same time. The other options (A, B, C) directly suggest a physical connection or interaction between the terranes by the time those geological features formed.

Question 16

Which feature on this figure formed entirely before joining of these two terranes?

Accepted Answer

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Question 17

Which of the following is NOT a type of terrane in California?

Accepted Answer

All of these terranes are present in California. The state's complex geology includes oceanic crust, island arcs, accretionary prisms, and displaced granitic rocks, reflecting its dynamic tectonic history.

Question 18

Which interpretation of the image is correct?

Accepted Answer

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Question 19

Which numbered area on this geologic map of North America would contain the oldest rocks exposed at the surface?

Accepted Answer