What did scientists think happened to cause the magnetic patterns they found?
Alternating bands of normal and reversed polarity matching the geomagnetic reversed time scale. What did scientists think happened to cause the magnetic patterns they found? As new sea floor forms, it records reversals in Earth's magnetic field.
What is the crack in the ocean floor through which magma rises called?
What is the crack in the ocean floor through which magma rises? a rift.
What finally confirmed Wegener’s theory of continental drift?
Alfred Wegener produced evidence in 1912 that the continents are in motion, but because he could not explain what forces could move them, geologists rejected his ideas. Almost 50 years later Harry Hess confirmed Wegener's ideas by using the evidence of seafloor spreading to explain what moved continents.
What is one result of the collision that formed Pangaea?
When continents collide, big mountains grow. The formation of Pangaea created long large mountain ranges. The mountains that formed then look a lot like the Himalayas do today.
How were the magnetic patterns on the seafloor discovered?
Data from magnetometers dragged behind ships looking for enemy submarines in WWII discovered amazing magnetic patterns on the seafloor. Rocks of normal and reversed polarity are found in stripes symmetrically about the mid-ocean ridge axis.
What causes magnetic stripes on the seafloor quizlet?
The rock of the ocean floor contains iron. As molten material cooled and hardenend, the iron bits inside lined up in the direction of Earth's magnetic poles, creating a pattern of magnetized stripes.
What causes seafloor spreading?
Seafloor spreading occurs at divergent plate boundaries. As tectonic plates slowly move away from each other, heat from the mantle's convection currents makes the crust more plastic and less dense. The less-dense material rises, often forming a mountain or elevated area of the seafloor.
What is seafloor spreading theory?
seafloor spreading, theory that oceanic crust forms along submarine mountain zones, known collectively as the mid-ocean ridge system, and spreads out laterally away from them.
Why was Alfred Wegener’s theory of continental drift rejected?
Wegener's inability to provide an adequate explanation of the forces responsible for continental drift and the prevailing belief that the earth was solid and immovable resulted in the scientific dismissal of his theories.
Why was continental drift rejected?
Geologists roundly denounced Wegener's continental drift theory after he published the details in a 1915 book called "The Origin of Continents and Oceans (opens in new tab)." Part of the opposition was because Wegener didn't have a good model to explain how the continents moved, something scientists later explained …
What resulted from the collision of tectonic plates quizlet?
What happens when two continental plates collide? The continental crust is pushed together and upward to form large MOUNTAIN ranges.
How were continents formed from Pangaea?
In 1912, German scientist Alfred Wegener proposed a theory he called continental drift. According to Wegener's theory, Earth's continents once formed a single, giant landmass, which he called Pangaea. Over millions of years, Pangaea slowly broke apart, eventually forming the continents as they are today.
When was magnetic striping on the seafloor discovered?
Oceanographic exploration in the 1950s led to a much better understanding of the ocean floor. Among the new findings was the discovery of zebra stripe-like magnetic patterns for the rocks of the ocean floor. These patterns were unlike any seen for continental rocks.
How do magnetic stripes form on the ocean floor serve as evidence for seafloor spreading?
When the Earth's magnetic field reverses, a new stripe, with the new polarity, begins. Such magnetic patterns led to recognition of the occurrence of sea-floor spreading, and they remain some of the strongest evidence for the theory of plate tectonics. The figure below includes two images of the ocean floor.
How does the pattern of magnetic stripes give evidence for seafloor spreading quizlet?
How do strips of magnetized rock on the ocean floor provide evidence of sea-floor spreading? Strips of ocean-floor basalt record the polarity of Earth's magnetic field at the time the rock formed. These strips form a pattern that is the same on both sides of the mid-ocean ridge.
What causes seafloor spreading quizlet?
The older rock moves outward on both sides of the ridge as new rock forms in the center of the ridge from cooling of molten material. This process is sea floor spreading.
How does the observed pattern of magnetic reversals support the theory of sea floor spreading?
When the Earth's magnetic field reverses, a new stripe, with the new polarity, begins. Such magnetic patterns led to recognition of the occurrence of sea-floor spreading, and they remain some of the strongest evidence for the theory of plate tectonics.
What causes the ocean floor to spread?
Seafloor spreading occurs at divergent plate boundaries. As tectonic plates slowly move away from each other, heat from the mantle's convection currents makes the crust more plastic and less dense. The less-dense material rises, often forming a mountain or elevated area of the seafloor.
What was the main reason Wegener’s continental drift hypothesis was rejected quizlet?
Wegener's hypothesis was rejected from geologists because he couldn't identify the cause of continental drift.
What was Alfred Wegener’s continental drift hypothesis quizlet?
What is the continental drift hypothesis? Proposed by Alfred Wegener, it states that Earth's continents have moved slowly to their current locations. All the continents were once connected as one landmass that broke apart 250 million years ago. This one landmass is called "Pangea," meaning "all land."
Why are magnetic patterns important evidence for plate tectonics?
Answer and Explanation: Magnetic patterns are important evidence for plate tectonics because we can use the magnetic signatures of rock to identify the movement of large… See full answer below.
What caused the continents to separate?
Wegener suggested that perhaps the rotation of the Earth caused the continents to shift towards and apart from each other. (It doesn't.) Today, we know that the continents rest on massive slabs of rock called tectonic plates. The plates are always moving and interacting in a process called plate tectonics.
What happens when oceanic oceanic plates collide?
When two oceanic plates converge, the cooler, denser one descends, or subducts, beneath the overriding plate and sinks into the mantle. When an oceanic plate meets a plate with a continent riding atop it, the oceanic plate is again subducted.
What happens when an oceanic plate collides with a continental plate quizlet?
What happens when an oceanic plate and a continental plate collide? Oceanic plate is subducted and some of the material rises upward and erupts as VOLCANO.
How were continents and oceans formed?
Today, tectonic plates continue to slowly slide around the surface, just as they have been doing for hundreds of millions of years. Geologists believe the interaction of the plates, a process called plate tectonics, contributed to the creation of continents.
How did land first form on Earth?
When and how Earth's earliest continents, the cratons, first rose above the oceans remains uncertain. Previous research suggested this emergence began roughly 2.5 billion years ago and was driven by plate tectonics — the drifting, crashing and diving of the giant plates of rock that now make up Earth's surface.
How does the pattern of magnetic stripes serve as evidence for seafloor spreading?
When the Earth's magnetic field reverses, a new stripe, with the new polarity, begins. Such magnetic patterns led to recognition of the occurrence of sea-floor spreading, and they remain some of the strongest evidence for the theory of plate tectonics.
How do magnetic stripes provide evidence of seafloor spreading?
When the Earth's magnetic field reverses, a new stripe, with the new polarity, begins. Such magnetic patterns led to recognition of the occurrence of sea-floor spreading, and they remain some of the strongest evidence for the theory of plate tectonics. The figure below includes two images of the ocean floor.
How magnetic patterns develop on the seafloor?
The striped magnetic pattern develops because, as oceanic crust pulls apart, magma rises to the surface at mid-ocean ridges and spills out to create new bands of ocean floor.
Why was Wegener’s continental drift theory rejected?
Wegener's inability to provide an adequate explanation of the forces responsible for continental drift and the prevailing belief that the earth was solid and immovable resulted in the scientific dismissal of his theories.