Question 1

Using the concepts of hot spots and plate tectonics, explain how each of the islands of the Hawaiian Island chain vary in age.

Accepted Answer

The Hawaiian Island chain is a result of the movement of the Pacific Plate over a hot spot in the Earth's mantle. A hot spot is an area of intense volcanic activity caused by a plume of hot magma rising from deep within the Earth. As the Pacific Plate moves northwestward over the hot spot, it creates a series of volcanic islands.

The oldest island in the Hawaiian chain is Kauai, which formed over 5 million years ago. As the Pacific Plate continued to move, new volcanic activity formed the islands of Oahu, Molokai, Lanai, Maui, and finally the Big Island of Hawaii, which is still actively growing due to ongoing volcanic eruptions.

The varying ages of the Hawaiian Islands can be attributed to the movement of the Pacific Plate over the hot spot. As the plate moves, older islands become more distant from the hot spot and undergo erosion, while new islands continue to form near the hot spot. This process results in a chain of islands that vary in age, with the oldest islands in the northwest and the youngest islands in the southeast. This demonstrates the dynamic nature of plate tectonics and the formation of volcanic islands.

Question 2

Discuss the evidence to support plate tectonics. In your discussion, include what lead to Alfred Wegener's Continental Drift Hypothesis, and what additional evidence is used today to support plate tectonics.

Accepted Answer

The evidence supporting plate tectonics is vast and compelling, with key pieces of evidence dating back to the early 20th century when Alfred Wegener proposed his Continental Drift Hypothesis. Wegener suggested that the continents were once joined together in a single landmass he called Pangaea, which over millions of years, broke apart and drifted to their current positions.

Wegener's hypothesis was based on several lines of evidence, including the jigsaw-like fit of the continents, similarities in rock types and mountain ranges across different continents, and the distribution of fossil species that were once thought to be unable to travel across vast oceans. However, Wegener's ideas were met with skepticism at the time due to the lack of a mechanism to explain how the continents could move.

Today, the evidence supporting plate tectonics includes the mapping of mid-ocean ridges and deep-sea trenches, the discovery of magnetic striping on the ocean floor that indicated seafloor spreading, and the identification of tectonic plate boundaries where earthquakes and volcanic activity are concentrated. Additionally, the study of paleomagnetism has provided further evidence, as the orientation of magnetic minerals in rocks can be used to track the movement of tectonic plates over time.

Furthermore, advancements in technology, such as GPS and satellite imagery, have allowed scientists to directly measure the movement of tectonic plates and monitor changes in the Earth's crust. This wealth of evidence has solidified our understanding of plate tectonics and its role in shaping the Earth's surface, from the formation of mountain ranges to the occurrence of earthquakes and volcanic eruptions. Overall, the evidence for plate tectonics is robust and continues to be supported by ongoing research and observations.

Question 3

__________ has emerged as a unifying theory that explains hundreds of years of independent observations of Earth's topographic features.

Accepted Answer

Plate tectonics

Question 4

It was __________ who realized that the Andes Mountains were slowly being pushed upward.

Accepted Answer

The answer of It was __________ who realized that the...

Question 5

__________ suggested __________ , in which all of the world's landmasses were once connected together in a huge supercontinent called __________ .

Accepted Answer

The answer of __________ suggested __________ , in which all...

Question 6

__________ is the preservation of Earth's magnetic field locked in minerals at the time of rock formation.

Accepted Answer

The answer of __________ is the preservation of Earth's magnetic...

Question 7

Earth is like a giant magnet, surrounded by an invisible __________ that permeates everything placed in the field.

Accepted Answer

The answer of Earth is like a giant magnet, surrounded...

Question 8

Through detailed paleomagnetic studies, scientists have been able to determine a chronology of __________ reversals of Earth's magnetic field.

Accepted Answer

The answer of Through detailed paleomagnetic studies, scientists have been...

Question 9

The principle mechanism by which heat is transferred from deep inside Earth to the base of the lithosphere is __________ .

Accepted Answer

The answer of The principle mechanism by which heat is...

Question 10

__________ plate margins are fractures in the lithosphere where two plates move apart.

Accepted Answer

The answer of __________ plate margins are fractures in the...

Question 11

__________ plate margins occur where two plates are moving toward each other.

Accepted Answer

The answer of __________ plate margins occur where two plates...

Question 12

___________ plate margins are fractures in the lithosphere where two plates slide past each other.

Accepted Answer

The answer of ___________ plate margins are fractures in the...

Question 13

Large, flat areas known as __________ are a major topographic feature of the seafloor.

Accepted Answer

The answer of Large, flat areas known as __________ are...

Question 14

An __________ marks the place where oceanic-capped lithosphere sinks into the asthenosphere.

Accepted Answer

The answer of An __________ marks the place where oceanic-capped...

Question 15

The Atlantic Ocean margins of the Americas, Africa, and Europe are examples of __________ continental margins.

Accepted Answer

The answer of The Atlantic Ocean margins of the Americas,...

Question 16

A __________ is a stable core of very ancient rock.

Accepted Answer

The answer of A __________ is a stable core of...

Question 17

The lithosphere behaves as is it were __________ on the asthenosphere.

Accepted Answer

The answer of The lithosphere behaves as is it were...

Question 18

__________ gravity anomalies result from concentrations of high-density rock under the surface.

Accepted Answer

The answer of __________ gravity anomalies result from concentrations of...

Question 19

Gases from __________ continue to play an important role in the climate and the long-term composition of the atmosphere.

Accepted Answer

The answer of Gases from __________ continue to play an...

Question 20

__________ has influenced virtually every part of the Earth system over the history of planet Earth.

Accepted Answer

The answer of __________ has influenced virtually every part of...

Quiz 5: The Tectonic Cycle