Geological Processes and Plate Tectonics

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Questions and Answers

What process describes the constant motion of tectonic plates?

Subduction

Mantle convection

Plate tectonics (correct)

Seafloor spreading

Which type of crust is denser than the other?

Oceanic crust is denser than all types of crust

Oceanic crust is denser than continental crust (correct)

Continental crust is denser than oceanic crust

Both crust types have the same density

At which type of boundary does new oceanic crust typically form?

Convergent boundaries

Divergent boundaries (correct)

Static boundaries

Transform boundaries

How does the thickness of a tectonic plate affect its density?

Density can vary depending on the material composition Signup and view all the answers

Which statement is true about oceanic crust in comparison to continental crust?

Oceanic crust has a greater concentration of iron Signup and view all the answers

What is the primary force that drives the movement of tectonic plates?

Movements of the mantle below Signup and view all the answers

What is the characteristic feature of oceanic crust compared to continental crust?

Oceanic crust is typically younger Signup and view all the answers

What happens during the process of seafloor spreading?

Plates move away from each other Signup and view all the answers

What effect do southeast winds have along the coast of Perú during normal conditions?

They push warm water out across the equatorial Pacific. Signup and view all the answers

What happens to the upwelling of nutrient-rich water along the Peruvian coast during El Niño?

It weakens and fails to operate effectively. Signup and view all the answers

During which phase is the thermocline shallower in the eastern Pacific?

El Niño. Signup and view all the answers

What change occurs in the atmospheric pressure over the southern Pacific and Indian Oceans, as discovered by Walker?

High pressure over the southern Pacific corresponds with low pressure over the Indian Ocean. Signup and view all the answers

What phenomenon was discovered by Sir Gilbert Walker in 1923?

The Southern Oscillation. Signup and view all the answers

What does the 10 centimeter mark on the scale represent?

The origin of modern man Signup and view all the answers

How do geologists determine the relative ages of rocks?

By examining radioisotope decay in rocks Signup and view all the answers

What do the terms high pressure and low pressure indicate regarding wind patterns?

Winds blow from high-pressure areas to low-pressure areas. Signup and view all the answers

What is a significant climate effect caused by El Niño events?

Altered rainfall patterns around the globe. Signup and view all the answers

What are the two main types of rocks mentioned in the content?

Igneous and sedimentary Signup and view all the answers

Which of the following best describes the results of Walker's analysis of meteorological data?

He found correlations between atmospheric pressures and wind patterns. Signup and view all the answers

What causes sedimentary rocks to form?

Erosion processes Signup and view all the answers

What is limestone classified as based on its origin?

Sedimentary rock Signup and view all the answers

What characteristic is specific to volcanic rocks?

Formed from lava flows or eruptions Signup and view all the answers

Which processes contribute to the formation of sedimentary rocks?

Weathering and deposition Signup and view all the answers

What happens to the remains of corals and calcareous organisms in limestone formation?

They accumulate as sediments Signup and view all the answers

What do scientists believe about the recovery of ecosystems after hurricanes?

They will likely recover as hurricanes are a natural part of the environment. Signup and view all the answers

What is noted as a necessary step for understanding the long-term effects of ecosystem changes?

Ongoing monitoring to observe recovery over time. Signup and view all the answers

What geological process led to the formation of Guam's basement volcanic bedrock?

Friction between the Pacific Plate and the Philippine Plate generating magma Signup and view all the answers

During which geological epoch did the Pacific Plate begin to move north-northwest and collide with the Philippine Plate?

Eocene Signup and view all the answers

What aspect of storm effects on ecosystems are scientists still uncertain about?

The details of the recovery process and human impacts. Signup and view all the answers

Which of the following areas are mentioned as being particularly affected by typhoons?

Marshall Islands Signup and view all the answers

What is the characteristic of the volcanic activity associated with the Facpi formation?

Submarine lava flows in the form of pillow basalt Signup and view all the answers

What type of threats do scientists mention as needing long-term study regarding ecosystem changes?

External threats and alien plants. Signup and view all the answers

How long did the Facpi formation process last?

3–4 million years Signup and view all the answers

Where did Guam's geological history supposedly begin?

Approximately 20° farther south of its current location Signup and view all the answers

What types of materials were primarily cast off during the volatile volcanism that followed the Facpi formation?

Large amounts of ash and other volcanic debris Signup and view all the answers

Which tectonic plates are involved in Guam's geological formation?

Pacific Plate and Philippine Plate Signup and view all the answers

What type of plate boundary is formed by the interaction of the Pacific Plate moving past the Philippine Plate before the mid-Eocene Epoch?

Transform boundary Signup and view all the answers

Study Notes

Plate Tectonics

Tectonic plates are large sections of Earth's crust resting on the mantle, influenced by mantle movements and various forces.
These plates are in continuous motion, engaging in processes known as plate tectonics.
Plate density varies, with oceanic crust being denser and containing heavier elements (e.g., iron) than continental crust, which is typically thicker and older.

Formation of Oceanic Crust

New oceanic crust forms at divergent boundaries in a process called seafloor spreading, primarily occurring at mid-ocean ridges.
As plates move apart, fresh lava emerges, creating new crust.

Geological History of Guam

Guam's geological formation started approximately 20° south of its current position along the Palau-Kyushu Ridge.
In the mid-Eocene Epoch (before 43 Ma), the Pacific Plate began colliding and subducting under the Philippine Plate.
This collision generated heat and magma, leading to volcanic activity under the Pacific Ocean.

Facpi Formation

The Facpi formation, consisting of the oldest surface volcanic rock on Guam, formed over 3-4 million years (43-39 Ma).
Initially consisted of submarine lava flows, later evolving into explosive volcanic eruptions with ash deposits.

El Niño and Atmospheric Pressure

Sir Gilbert Walker identified the Southern Oscillation in 1923, revealing correlations between atmospheric pressure changes over the Pacific and Indian Oceans.
High pressure over the Pacific correlates with low pressure over the Indian Ocean, affecting trade winds and weather patterns.

Impacts of Typhoons

Typhoons significantly affect atolls, particularly in regions like the Marshall Islands and the Federated States of Micronesia.
There is ongoing research regarding the recovery of ecosystems post-hurricane, emphasizing the need for long-term monitoring and understanding of ecosystem dynamics.

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Description

Explore the dynamic world of plate tectonics, focusing on features such as oceanic crust formation and the geological history of regions like Guam. Understand the mechanisms driving tectonic movement and the differences between oceanic and continental crust. Test your knowledge on these fundamental concepts in Earth science.