Evidence of Plate Tectonics (HS-ESS1-5): Evaluate evidence of the past and current movements of continental and oceanic crust and the theory of plate tectonics to explain the ages of crustal rocks.
To explain the ages of crustal rocks, scientists evaluate evidence of the past and current movements of continental and oceanic crust within the framework of plate tectonics. This theory helps to understand how the Earth's lithosphere is divided into tectonic plates that move over time, leading to the formation, destruction, and recycling of crustal rocks. By studying the patterns of seafloor spreading, magnetic anomalies, fossil distributions, and the age differences between oceanic and continental rocks, scientists can trace the history of plate movements and the processes that shape Earth's surface over millions of years.
Main Concepts:
- Plate tectonics theory is the scientific explanation for the movement of Earth's lithospheric plates and the geological processes resulting from this movement. The lithosphere is the solid outer layer of the Earth, which consists of several large plates that fit together like puzzle pieces. These plates can move due to the flow of the underlying mantle.
- One of the pieces of evidence supporting the theory of plate tectonics is the ages of crustal rocks. Scientists can determine the age of rocks using various techniques such as radiometric dating. By analyzing the ages of rocks across different plates, scientists have been able to support the idea that plates move and interact with each other.
- The ages of oceanic crust increase with distance from mid-ocean ridges. This is because new oceanic crust is formed at these ridges through volcanic activity, pushing older crust away from the ridge as it spreads outwards. This process, known as seafloor spreading, is one of the main mechanisms driving plate tectonics.
- The North American continental crust contains a much older central ancient core compared to the surrounding continental crust. This is due to complex and numerous plate interactions. The ancient core, known as the Canadian Shield, formed about 2.5 billion years ago and is surrounded by younger rocks that have been added over time due to plate interactions.
NGSS Aligned Testing Question
The model below represents the polarity patterns found on the Atlantic Ocean floor over geologic time.
| Which statement identifies the evidence for how the past and current movements of oceanic crust explain the ages of this ocean floor rock? | |
|---|---|
| 1 | Oceanic crust at the mid-ocean ridge in block diagram A is now the youngest normal magnetic polarity rock found in block diagram C. |
| 2 | Ocean crust at the mid-ocean ridge in block diagram A is now the oldest normal magnetic polarity rock found in block diagram C. |
| 3 | The reverse magnetic polarity rock closest to the mid-ocean ridge in block diagram A is younger than the reverse magnetic polarity rock closest to the mid-ocean ridge in block diagram B. |
| 4 | The reverse magnetic polarity rock in block diagram B is the same age as the normal magnetic polarity rock in block diagram B. |
General Question and Answer Section
- What is plate tectonics?
Answer: Plate tectonics is a scientific theory that explains how Earth's surface is made up of rigid plates that move over the underlying mantle.
- What geological processes are a result of plate tectonics?
Answer: Plate tectonics is responsible for various geological processes such as the formation of mountains, earthquakes, and the creation and destruction of ocean basins.
- How does evidence of the ages of crustal rocks support the theory of plate tectonics?
Answer: Evidence of the ages of crustal rocks can be used to support the theory of plate tectonics by showing how the movement of plates has led to the formation of different types of crust.
- What happens to the ages of oceanic crust with increasing distance from mid-ocean ridges?
Answer: The ages of oceanic crust increase with distance from mid-ocean ridges as a result of plate spreading.
- Why does the North American continental crust contain a much older central ancient core compared to the surrounding continental crust?
Answer: The North American continental crust contains a much older central ancient core compared to the surrounding continental crust as a result of complex and numerous plate interactions.
- What is the significance of studying the ages of crustal rocks?
Answer: Studying the ages of crustal rocks can help us better understand the movement of plates and the geological processes resulting from this movement.
- How does plate tectonics explain the formation of mountains?
Answer: Plate tectonics explains the formation of mountains through the collision of two plates, causing the crust to buckle and fold.
- What is plate spreading?
Answer: Plate spreading is the movement of plates away from each other, resulting in the formation of new crust.
- What is a mid-ocean ridge?
Answer: A mid-ocean ridge is an underwater mountain range where new oceanic crust is formed through plate spreading.
- What is the difference between oceanic and continental crust?
Answer: Oceanic crust is thinner and denser than continental crust and is primarily composed of basalt, while continental crust is thicker and less dense and is primarily composed of granite.
*continue your studies by accessing another review sheet below*
Space Systems: HS-ESS1-1 : HS-ESS1-2 : HS-ESS1-3 : HS-ESS1-4 : HS-ESS1-7
History of the Earth: HS-ESS1-5 : HS-ESS1-6 : HS-ESS2-1
Earth's Systems: HS-ESS2-2 : HS-ESS2-3 : HS-ESS2-5 : HS-ESS2-6 : HS-ESS2-7
Weather and Climate: HS-ESS2-4 : HS-ESS3-5 : HS-ESS2-8
Human Sustainability: HS-ESS3-1 : HS-ESS3-2 : HS-ESS3-3 : HS-ESS3-4 : HS.ESS3-6
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