Questions and Answers
What is the primary rock type found in oceanic crust?
Which element is predominantly found in the composition of continental crust?
What is the typical thickness range of oceanic crust?
Which statement regarding the age of oceanic and continental crust is correct?
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What defines a major tectonic plate?
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What defines the lithosphere?
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Which statement accurately compares oceanic and continental crust?
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What is the primary reason that oceanic crust is denser than continental crust?
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What characterizes the asthenosphere?
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What is the thickness range of oceanic crust?
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What is one characteristic that distinguishes continental crust from oceanic crust?
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In terms of density, how do oceanic and continental crust compare?
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Which of the following accurately describes the composition of oceanic crust?
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Which minor tectonic plate has the largest area?
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What is the approximate area of the Cocos Plate?
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Which of the following statements best describes microplates?
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What can be inferred about the locations of earthquake epicenters and active volcanoes?
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Which minor plate has the smallest area?
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Why is it crucial to identify earthquake-prone areas?
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How many major tectonic plates are typically recognized in scientific classification?
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What role do earthquake epicenter maps play in geology?
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Study Notes
The Lithosphere
- The lithosphere is the rigid outer layer of Earth, consisting of the crust and uppermost mantle.
- It plays a crucial role in plate tectonics, forming "plates" that float on the underlying asthenosphere.
Asthenosphere
- The asthenosphere is a solid layer with plasticity located just below the lithosphere.
- Lithospheric plates are able to move and float on this more flexible layer.
Crust Types: Oceanic vs. Continental
- Oceanic crust is denser than continental crust due to its composition primarily of basalt.
- Continental crust is thicker, measuring 25-70 km compared to oceanic crust's 5-10 km.
Density Comparison
- Oceanic crust: denser composition (primarily iron, magnesium).
- Continental crust: less dense, made mostly of granite (silica, aluminum).
Geologic Age
- Continental crust is significantly older than oceanic crust, with the oldest continental crust estimated at 4 billion years.
- Oceanic crust has a maximum age of around 200 million years.
Tectonic Plates
- Tectonic plates are massive slabs of solid rock, either oceanic or continental, and vary greatly in size and thickness.
- Major plates are larger than 20 million km², while minor plates are smaller.
Specific Minor Plates
- Nazca Plate: 15,600,000 km²
- Philippine Sea Plate: 5,500,000 km²
- Saudi Arabian Plate: 5,000,000 km²
- Caribbean Plate: 3,300,000 km²
- Cocos Plate: 2,900,000 km²
- Scotia Plate: 1,600,000 km²
- Juan de Fuca Plate: 250,000 km²
Microplates
- Often grouped with adjacent principal plates on tectonic maps, microplates are smaller tectonic units.
Scientific Basis for Plate Division
- Scientists divide the lithosphere based on geological features and seismic activity, studying the distribution of earthquakes, volcanoes, and mountain belts.
Earthquake Epicenters
- Earthquake epicenters are distributed predominantly along tectonic plate boundaries.
- Identifying earthquake-prone areas is critical for disaster preparedness and risk management.
Active Volcanoes
- The distribution of active volcanoes often coincides with earthquake epicenters, indicating tectonic activity.
- This comparison suggests a strong relationship between seismic events and volcanic activity globally.
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Description
Explore the distribution of active volcanoes, earthquake epicenters, and major mountain belts in this quiz. This quiz covers key concepts related to the lithosphere and Earth's interior as part of the 2022 LCP curriculum.