Science 10: Lesson 3 Processes That Occur Along The Plate Boundaries Part 2

D’Marianne

23 Aug 202006:14

Summary

TLDRIn this educational video, Marian Soriano introduces students to plate tectonics, focusing on the processes at plate boundaries. She explains convergent boundaries where plates collide, forming trenches, volcanoes, and causing earthquakes, including tsunamis like the 2011 Japan disaster. Soriano also describes divergent boundaries, where plates move apart, creating oceanic ridges and rift valleys, and the youngest rocks near these areas. Transform faults, where plates slide past each other, are highlighted for their frequent seismic activity. The lesson aims to inform and engage, with examples like Iceland and the San Andreas Fault.

Takeaways

🌏 Convergent plate boundaries occur when lithospheric plates move towards each other, leading to subduction and the formation of trenches, volcanic arcs, and earthquakes.
🌋 Oceanic-continental convergence results in trenches, volcanic arcs, and can trigger earthquakes that may cause tsunamis, as exemplified by the 2011 Japan earthquake.
🏞️ Oceanic-oceanic convergence leads to the formation of trenches, volcanic island arcs, and strong earthquakes that can generate tsunamis.
🏔️ Continental-continental convergence does not create subduction zones but instead forms mountain ranges and causes shallow earthquakes due to the collision of crustal plates.
🌊 Divergent plate boundaries are characterized by plates moving apart, leading to the creation of oceanic ridges and reef valleys due to magma formation from mantle convection currents.
🌋 The Mid-Atlantic Ridge is a mid-ocean ridge that is part of the longest mountain range in the world, formed by divergent plate movement.
📊 Rocks near the oceanic ridge are younger than those far from it, indicating the process of seafloor spreading and the creation of new crust.
🏞️ Continental divergence can lead to the formation of a continental rift valley, which may eventually evolve into a narrow sea and then a widened ocean.
🇮🇸 Iceland is situated above the Eurasian and North American plates that are diverging, with the Zinfandler National Park being a notable attraction.
🏗️ Transform fault plate boundaries occur when plates slide past each other horizontally, causing earthquakes due to the jagged edges of plates catching and sticking.
🌀 Transform faults, such as the San Andreas Fault, are characterized by horizontal movement without the destruction of the plate's leading edge, resulting in earthquakes rather than volcanic activity or mountain formation.

Q & A

What is a convergent plate boundary?
-A convergent plate boundary is where two lithospheric plates are moving towards each other, often resulting in one plate being subducted beneath the other, leading to the formation of trenches, volcanic arcs, and earthquakes.
What happens during the convergence of oceanic and continental crustal plates?
-During the convergence of oceanic and continental crustal plates, the denser oceanic plate is subducted under the continental plate, forming trenches and volcanic arcs, and causing earthquakes.
What are the consequences of the convergence of oceanic to oceanic crustal plates?
-The convergence of oceanic to oceanic crustal plates leads to the formation of trenches, volcanic island arcs, and strong earthquakes that can generate tsunamis.
Why do two continental crustal plates not form volcanoes when they collide?
-When two continental crustal plates collide, there is no subduction zone because neither plate is dense enough to be forced under the other, resulting in a collision zone that forms mountain ranges and shallow earthquakes instead of volcanoes.
What is a divergent plate boundary?
-A divergent plate boundary occurs when lithospheric plates are moving apart from each other, allowing magma to rise from the mantle and create new crust, forming features like oceanic ridges and rift valleys.
How are oceanic ridges formed?
-Oceanic ridges are formed at divergent boundaries where convection currents in the mantle cause magma to rise and create new crust as the plates move apart, leading to the development of underwater mountain ranges.
What is a reef valley and how does it form?
-A reef valley is a linear shaped lowland that forms between oceanic ridges as the oceanic crust, being thinner than continental crust, stretches and creates a depression in the ocean floor.
Why are rocks near the mid-Atlantic ridge younger than those far from it?
-Rocks near the mid-Atlantic ridge are younger because this is an active divergent boundary where new oceanic crust is continuously being formed by the upwelling of magma from the mantle.
How does a transform fault plate boundary differ from a divergent boundary?
-A transform fault plate boundary involves plates sliding past each other horizontally without creating or destroying crust, resulting in earthquakes rather than the formation of new crust or volcanic activity seen in divergent boundaries.
What causes earthquakes at transform fault boundaries?
-Earthquakes at transform fault boundaries are caused by the jagged edges of tectonic plates catching and sticking as they slide past each other, building up stress that is released when the plates suddenly slip.
Why are most transform faults located within ocean basins?
-Most transform faults are located within ocean basins because this is where many of the Earth's tectonic plates meet and interact, although some, like the San Andreas Fault, do cut through continental crust.

Outlines

00:00

🌏 Plate Tectonics and Convergent Boundaries

This paragraph introduces the concept of plate tectonics, focusing on convergent plate boundaries where lithospheric plates move towards each other. It explains the process of subduction, where one plate is forced under another, leading to the formation of trenches, volcanic arcs, and earthquakes. The paragraph also discusses the 2011 Japan tsunami, which was triggered by a strong earthquake at a convergent boundary between oceanic plates. Additionally, it touches on the collision of continental plates, which results in mountain ranges and shallow earthquakes, rather than volcanic activity.

05:00

🌋 Divergent and Transform Fault Boundaries

The second paragraph delves into divergent plate boundaries, where plates move apart and new crust is formed, as seen in oceanic ridges and continental rift valleys. It describes the formation of oceanic ridges due to convection currents and the creation of a reef valley between ridges. The paragraph highlights the Mid-Atlantic Ridge as an example and explains the age distribution of oceanic crust. It also covers the process of continental plates diverging to form a rift valley and eventually an ocean, using Iceland as an example. Lastly, the paragraph explains transform fault boundaries, where plates slide past each other, causing earthquakes, and uses the San Andreas Fault as an illustration.

Mindmap

Keywords

💡Convergent Plate Boundary

A convergent plate boundary is a type of tectonic plate interaction where two plates move towards each other. This process is central to the video's theme as it explains the geological phenomena that occur when plates converge, such as subduction, which leads to the creation of trenches, volcanic arcs, and earthquakes. An example from the script is the convergence of oceanic to continental plates, resulting in the formation of trenches and volcanic arcs.

💡Subduction

Subduction is the process where one tectonic plate moves under another and sinks into the mantle. It is a key concept in the video, as it describes the movement of plates at convergent boundaries, leading to the formation of magma and contributing to volcanic activity. The script mentions subduction in the context of oceanic to continental plate convergence.

💡Trench

A trench is a long and narrow depression in the Earth's crust, typically found in the ocean floor. In the video, trenches are a result of convergent plate boundaries where one plate is subducted beneath another. The script uses trenches as an example of geological features formed by the interaction of oceanic and continental plates.

💡Volcanic Arc

A volcanic arc is a chain of volcanoes that form along a convergent plate boundary. The video explains that volcanic arcs are created when one plate is subducted beneath another, causing magma to rise and form volcanoes. The script specifically mentions the formation of volcanic arcs in the convergence of oceanic to continental plates.

💡Earthquake

An earthquake is the shaking of the Earth's surface caused by the sudden release of energy in the Earth's crust. The video discusses earthquakes in the context of plate tectonics, particularly at convergent and transform plate boundaries. The script provides the example of the 2011 earthquake in Japan, which was triggered by the movement of plates.

💡Divergent Plate Boundary

A divergent plate boundary is where two tectonic plates move apart from each other. This concept is crucial to the video's narrative as it explains the process that leads to the creation of new crust and geological features like oceanic ridges and rift valleys. The script describes how divergent boundaries in oceanic plates lead to the formation of oceanic ridges and reef valleys.

💡Oceanic Ridge

An oceanic ridge is an underwater mountain range formed by plate tectonics at divergent boundaries. The video uses the term to illustrate the process by which new crust is created as plates move apart, with magma rising from the mantle to fill the gap. The script mentions the Mid-Atlantic Ridge as an example of an oceanic ridge.

💡Reef Valley

A reef valley, also known as a rift valley, is a linear-shaped lowland that forms between oceanic ridges. The video explains that reef valleys develop due to the thinning of the oceanic crust as plates diverge. The script provides the context that reef valleys are formed in the process of plate divergence and are characterized by their linear shape.

💡Transform Fault Plate Boundary

A transform fault plate boundary is where two plates slide past each other horizontally. The video discusses this type of boundary as a place where plates do not create or destroy crust but instead cause friction and earthquakes. The script uses the San Andreas Fault as an example of a transform fault boundary.

💡Tectonic Plates

Tectonic plates are large slabs of the Earth's lithosphere that move and interact with each other. The concept of tectonic plates is foundational to the video's theme, as it underpins the discussion of plate boundaries and the geological processes that occur at these boundaries. The script refers to the movement of tectonic plates in the context of convergent, divergent, and transform boundaries.

💡Convection Currents

Convection currents are the flow of material within the mantle due to heat transfer from the Earth's core. The video explains that these currents are responsible for the movement of tectonic plates and the creation of magma at divergent boundaries. The script describes how convection currents rise beneath the oceanic crust, leading to the formation of oceanic ridges.

Highlights

Introduction to plate tectonics and convergent plate boundaries.

Explanation of lithospheric plates moving towards each other and subduction process.

Formation of trenches, volcanic arcs, and earthquakes due to oceanic-continental plate convergence.

Tsunami generation from strong earthquakes at oceanic-oceanic plate convergence.

Mountain range creation and shallow earthquakes from continental-continental plate collision.

Continuation to part two focusing on divergent plate boundaries.

Description of lithospheric plates moving apart and oceanic ridge formation.

Process of oceanic ridge formation due to convection currents and magma creation.

The Mid-Atlantic Ridge as part of the longest mountain range in the world.

Age distribution of oceanic crust with younger rocks near oceanic ridges.

Divergent boundaries also known as constructive plate margins due to new material formation.

Development of continental rift valleys and seas from divergent continental plates.

Iceland as an example of a country formed by divergent plates between the Eurasian and North American plates.

Introduction to transform fault plate boundaries and their simulation.

Earthquake generation at transform faults due to jagged plate edges and stress release.

San Andreas Fault as an example of a transform fault cutting through continental crust.

Summary of divergent and transform plate boundaries, their effects, and phenomena.

Conclusion and sign-off by Marian Soriano, inviting students to the next lesson.