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Questions and Answers
What did Alfred Wegener name the supercontinent before the continents split apart?
What was the main problem with the theory that Earth was unchanging, as discovered by Wegener in 1911?
Why did other scientists, primarily geologists, reject Wegener's theory in the 1930s?
What was a key piece of evidence that helped scientists accept Wegener's theory in the 1960s?
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In which decade did Alfred Wegener introduce the continental drift hypothesis?
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What did Alfred Wegener find problematic with the theory of unchanging Earth in 1911?
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Which scientists rejected Alfred Wegener's theory primarily in the 1930s?
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What evidence did Alfred use to support his hypothesis?
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What led to a new understanding of how the Earth's crust was put together?
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What are the seven major tectonic plates listed in the lesson?
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What is the name of the long mountain range that forms the boundary of many major tectonic plates?
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What forces drive mechanisms to build new Earth material and recycle old back into Earth?
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Which type of boundary occurs when two plates slide past each other?
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Where does subduction typically occur in plate tectonics?
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What does seafloor spreading refer to?
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Why do earthquakes commonly occur at transform boundaries?
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What type of boundary is characterized by one plate sinking beneath another?
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What is the main process responsible for the formation of new oceanic crust along the Mid-Ocean Ridge?
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What evidence supported the theory of seafloor spreading and plate tectonics in the text?
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What is the term used to describe the preserved geomagnetic signal in rocks and minerals?
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How is paleomagnetism related to plate tectonics theory?
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What phenomenon explains the alternating stripes of normal and reversed polarity on the ocean floor away from the ridge?
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Which scientist proposed the early concept of continental drift before plate tectonics theory emerged?
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What do thinner layers of sediment near the crest and thicker layers farther out indicate about the oceanic crust?
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How did scientists determine that both sides of a mid-ocean ridge were created at the same time?
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What type of polarity do younger stripes of ocean floor closest to the ridge typically exhibit?
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What type of rocks were found closer to the crest of the ridge?
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What did Alfred Wegener name the supercontinent before the continents split apart?
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What was the main problem that Alfred Wegener found with the theory of an unchanging Earth in 1911?
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When did Alfred Wegener's continental drift hypothesis resurface and get accepted as part of plate tectonic theories?
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What was the accepted theory about Earth's continents before Alfred Wegener's hypothesis gained acceptance?
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What led scientists to understand that the Earth's crust is a jigsaw puzzle of moving pieces?
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What type of evidence helped other scientists accept Alfred Wegener's theory of continental drift?
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Which type of plate boundary creates underwater mountain ranges or rift valleys?
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What is the main driving force behind the movement of tectonic plates?
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Which decade saw Alfred Wegener introduce his continental drift hypothesis?
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What creates areas of subduction or collision at convergent boundaries?
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What aspect of continents did Alfred Wegener's theory primarily focus on?
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What was the purpose of the Deep Sea Drilling Project (DSDP) mentioned in the text?
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Why was Alfred Wegener's continental drift hypothesis initially rejected by other scientists in the 1930s?
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Which scientific community primarily rejected Alfred Wegener's theory in the 1930s?
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What specific mechanism drives the creation of new Earth material and recycles old material back into Earth?
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At which geological feature can you find a fault line due to plates sliding past each other?
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What crucial piece of evidence helped scientists accept Alfred Wegener's theory in the 1960s?
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What causes earthquakes at transform boundaries?
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What did scientists use as critical evidence to support Alfred Wegener's theory of continental drift?
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In what decade did scientists around the world start accepting Alfred Wegener's continental drift theory?
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What is the basis of plate tectonics theory as mentioned in the text?
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What does the alternating polarity of stripes on the ocean floor away from the ridge indicate?
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What phenomenon is created by stationary mantle plumes heating the crust and forming a chain of volcanoes?
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What is the study of ancient geomagnetic records preserved by rocks and minerals called?
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How do rocks found at different ages but the same location pointing to different magnetic poles contribute to plate tectonics understanding?
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What was used to explain seafloor spreading at mid-ocean ridges based on paleomagnetic data?
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What do thinner layers of sediment at the crest and thickened layers farther out indicate about oceanic crust?
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What has been used as evidence to support the existence of plate tectonic theory?
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Why are alternating stripes of normal and reversed polarity on the ocean floor significant?
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How did scientists determine that both sides of a mid-ocean ridge were created simultaneously?
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What did Alfred Wegener propose as a predecessor to plate tectonics theory?
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What does paleomagnetism primarily study according to the text?
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Study Notes
Continental Drift and Plate Tectonics
- Alfred Wegener named the supercontinent before the continents split apart as Pangaea.
- The main problem with the theory of an unchanging Earth was that it did not account for the existence of similar fossil species found on different continents, as discovered by Wegener in 1911.
Rejection and Acceptance of Wegener's Theory
- Other scientists, primarily geologists, rejected Wegener's theory in the 1930s because it was too radical and lacked evidence.
- A key piece of evidence that helped scientists accept Wegener's theory in the 1960s was the discovery of mid-ocean ridges and the process of seafloor spreading.
Plate Tectonics
- The seven major tectonic plates are not listed in the lesson.
- The long mountain range that forms the boundary of many major tectonic plates is the Mid-Ocean Ridge.
- Convection currents in the Earth's mantle drive the mechanisms that build new Earth material and recycle old material back into the Earth.
Types of Plate Boundaries
- Transform boundaries occur when two plates slide past each other, and are characterized by fault lines.
- Subduction typically occurs at convergent boundaries.
- Seafloor spreading refers to the process of new oceanic crust being created at mid-ocean ridges.
- Earthquakes commonly occur at transform boundaries due to the friction generated by the plates sliding past each other.
- Subduction zones are characterized by one plate sinking beneath another.
- The main process responsible for the formation of new oceanic crust along the Mid-Ocean Ridge is seafloor spreading.
Paleomagnetism and Seafloor Spreading
- Paleomagnetism is the study of ancient geomagnetic records preserved by rocks and minerals.
- Paleomagnetism is related to plate tectonics theory as it provides evidence for seafloor spreading and the movement of tectonic plates.
- The alternating stripes of normal and reversed polarity on the ocean floor away from the ridge indicate the process of seafloor spreading and the movement of the Earth's crust.
Early Concepts and Evidence
- Alfred Wegener introduced the continental drift hypothesis in the 1910s.
- Thinner layers of sediment near the crest and thicker layers farther out indicate that the oceanic crust is being created at the Mid-Ocean Ridge.
- Scientists determined that both sides of a mid-ocean ridge were created at the same time by dating the rocks on either side of the ridge.
- Younger stripes of ocean floor closest to the ridge typically exhibit normal polarity.
- Basaltic rocks were found closer to the crest of the ridge.
Acceptance and Understanding
- Alfred Wegener's continental drift hypothesis was initially rejected by other scientists in the 1930s but resurfaced and gained acceptance in the 1960s as part of plate tectonic theories.
- The accepted theory about Earth's continents before Alfred Wegener's hypothesis gained acceptance was that the continents were fixed and unchanging.
- The study of paleomagnetism and seafloor spreading led scientists to understand that the Earth's crust is a jigsaw puzzle of moving pieces.
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Description
Test your knowledge on the continental drift hypothesis introduced by Alfred Wegener in 1912, which suggests that all continents were once a single landmass called Pangea and then drifted apart. Explore the concept of changing Earth configurations and Wegener's findings.
