Plate Tectonics and Hawaiian Islands

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Questions and Answers

What effect does the movement of tectonic plates have on the age of the Hawaiian Islands?

The ages show random variation towards the Big Island.

The ages remain constant relative to the tectonic plate.

The ages increase as you go toward the Big Island of Hawaii.

The ages decrease as you go toward the Big Island of Hawaii. (correct)

How does paleomagnetism provide evidence for plate tectonics?

It tracks the movement of continents based on fossil records.

It measures the distance between tectonic plates over time.

It records the ancient orientation of Earth’s magnetic field when minerals formed. (correct)

It shows the alignment of iron minerals with the sun's position.

What phenomenon does not support the concept of the movement of magnetic poles?

Rock formations showing alignment with the current magnetic field. (correct)

Reversal bands produced by changing magnetic polarity.

Apparent polar wandering indicating pole movement over geologic time.

Magnetic minerals from different ages suggesting rocks have moved.

What do magnetic reversals on the ocean floor indicate?

Changes in Earth's magnetic field have been recorded in ocean basalt. Signup and view all the answers

What is the main factor controlling the age of the oceanic crust?

Plate motion and seafloor spreading. Signup and view all the answers

Which of the following best describes the age of current oceanic crust?

It ranges from 0 to 180 million years. Signup and view all the answers

Which statement about the formation of the Hawaiian Islands is true?

They moved away from a mantle plume over time. Signup and view all the answers

Which process is not associated with the theory of seafloor spreading?

Permanent anchoring of oceanic crust to continental plates. Signup and view all the answers

What feature is created at a divergent plate boundary?

Rift valleys Signup and view all the answers

Which geological feature is formed as a result of ocean-continent convergent boundaries?

Continental volcanic arcs Signup and view all the answers

What occurs during continental rifting?

Warping of the crust followed by rift valley formation Signup and view all the answers

Which of the following is NOT a type of convergent plate boundary?

Rift-Continental Signup and view all the answers

Which process occurs at an ocean-ocean convergent boundary?

Generation of an island volcanic arc Signup and view all the answers

What happens to oceanic lithosphere at convergent boundaries?

It is destroyed Signup and view all the answers

What feature is characteristic of a continent-continent convergent boundary?

Mountain belts Signup and view all the answers

What is the end product of continental rifting?

Creation of new oceanic crust Signup and view all the answers

What type of plate boundary occurs where two plates are moving apart?

Divergent Signup and view all the answers

What feature is formed at a convergent boundary where an oceanic plate meets a continental plate?

Deep-ocean trench Signup and view all the answers

What is the main driving force of plate motion at subduction zones?

Slab pull Signup and view all the answers

Which layer of the Earth is primarily responsible for the convection currents that drive plate tectonics?

Mantle Signup and view all the answers

What geological feature is typically found at mid-ocean ridges?

Volcanoes Signup and view all the answers

What happens to oceanic crust at convergent plate boundaries?

It is destroyed Signup and view all the answers

During magnetic reversals, what happens to the orientation of Earth's magnetic field?

It flips direction Signup and view all the answers

What type of plate boundary is characterized by plates sliding past one another?

Transform Signup and view all the answers

Study Notes

Hawaiian Islands Formation

Ages of the Hawaiian Islands increase towards the Big Island, indicating formation at an ocean ridge.
Ages decrease toward the Big Island, demonstrating movement over a hot spot or mantle plume.
Hawaiian Islands have remained relatively stationary concerning North America.

Paleomagnetism

Iron in minerals aligns with Earth's magnetic field during mineral formation.
Magnetic properties of iron atoms become fixed as magma cools below Curie point (580°C), acting as a "fossil compass."
Paleomagnetism provides a historical record of Earth's magnetic field orientation at the time of mineral formation.

Apparent Polar Wandering

Magnetic minerals from the same location but different ages indicate that the North Pole has shifted over time.
Movement of the rocks rather than the magnetic poles leads to the conclusion of continental drift.
The paths of magnetic poles correlate with the Pangaea supercontinent model.

Magnetic Reversals on the Ocean Floor

Polarity of Earth's magnetic field reverses every million to hundreds of thousands of years.
Iron in ocean basalt records these changes, creating reversal bands centered around ocean spreading centers.

Ocean Floor Age and Plate Motion

All existing ocean crust formed post-Pangaea breakup, around 200 million years ago.
Present-day oceanic crust varies in age from 0 to 180 million years, being youngest at divergent margins.
Oldest oceanic crust found at tectonically inactive continental margins.

Divergent Plate Boundary

New divergent plate boundaries can form within continents, starting with crust warping, leading to rift valley formation and eventually ocean creation.
Example: East African Rift.

Convergent Plate Boundary

Involves the collision of two tectonic plates, with the denser oceanic lithosphere subducting beneath the less dense continental lithosphere.
Results in oceanic lithosphere destruction and creation of continental crust through volcanic activity.

Types of Convergent Boundaries

Ocean-Continent Convergence: Forms a Continental Volcanic Arc; example: Cascade Range in the Northwestern US.
Ocean-Ocean Convergence: Produces an Island Volcanic Arc; examples: Japan and the Aleutian Islands.
Continent-Continent Convergence: No subduction occurs; creates mountain ranges from deformed rocks.

Forces Driving Plate Motion

Mantle Convection: Upward movement of less dense material and downward movement of denser material.
Slab Pull: Subducting ocean slab, being cold and dense, sinks and pulls the plate down.
Ridge Push: Elevated ridges cause oceanic material to slide down the flanks.

Self-Test Basics

Types of plate boundaries (divergent and convergent) determine geological features like deep-ocean trenches and mid-ocean ridges.
New continental crust formation occurs at divergent margins; oceanic crust is destroyed at convergent boundaries.

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Description

This quiz covers the principles of plate tectonics with a focus on the formation of the Hawaiian Islands. It explores how the ages of the islands provide evidence for their movement over a hot spot. Additionally, it addresses the concept of paleomagnetism in relation to tectonic activities.