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What causes the strange stripes on the seafloor?
These surveys revealed a series of invisible magnetic “stripes” of normal and reversed polarity in the sea floor, like that shown in the figure below. The patterns reflect the creation and spreading of oceanic crust along the mid-oceanic ridges. Basalt forming at the ridge crest picks up the existing magnetic polarity.
Why are there paleomagnetic stripes on the ocean floor?
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. Later, after the planet’s magnetic field flips again, the next stripe of new ocean floor aligns its polarity in the opposite direction.
What causes zebra pattern on the ocean floor?
Magnetic ‘zebra stripes’ When seafloor lava solidifies at the seafloor, its magnetic crystals are quenched in alignment with Earth’s magnetic field, and the rocks’ magnetic “polarity” is preserved.
How do magnetic stripes of iron in ocean rock?
How do magnetic stripes of iron in ocean rock provide evidence of seafloor spreading? They show how the density of the seafloor has changed. They reveal a matching pattern on either side of the ridge. They reveal differences in the mineral composition of newly created rock.
How did paleomagnetic stripes help to prove that the ocean floor is spreading at a mid-ocean ridge?
Magnetic reversals show up as bands of alternating polarity in the slowly spreading seafloor. This explanation of magnetic striping by paleomagnetism convinced scientists that new oceanic crust was being continually formed at mid-oceanic ridges. Seafloor spreading was accepted as a reality.
What are paleomagnetic stripes?
The pattern of magnetic stripes is actually called the “paleomagnetic anomaly pattern.” It’s easy to understand that it’s a pattern and it’s magnetic. The “paleo” part is a prefix indicating “ancient.” Most of the seafloor pattern excapt at midocean ridges was formed in the past, i.e. ancient.
How are the magnetic stripes formed?
When lava gets erupted at the mid-ocean ridge axis it cools and turns into hard rock. As it cools it becomes permanently magnetized in the direction of the Earth’s magnetic field. This creates a symmetrical pattern of magnetic stripes of opposite polarity on either side of mid-ocean ridges.
How do magnetic stripes on the ocean floor serve as evidence for seafloor spreading group of answer choices?
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. The pattern shows that ocean floor forms along mid-ocean ridges and then moves away from the ridge.
What are the magnetic stripes on the ocean floor?
At the mid-ocean ridge spreading axis, these flips in the direction of the Earth’s magnetic field are recorded in the magnetization of the lava. This creates a symmetrical pattern of magnetic stripes of opposite polarity on either side of mid-ocean ridges.
How are magnetic stripes formed on the ocean floor?
Over time, the Earth’s magnetic field reverses its north-to-south polarity, and the magnetic minerals point in the opposite direction, creating a striped pattern. The discovery of magnetic stripes on the seafloor in the 1950s validated the plate tectonics theory for the geological community.
How is the age of the earth related to its magnetic stripes?
Assuming that the ocean floor moved away from the spreading center at a rate of several centimeters per year, they found there was a remarkable correlation between the ages of the Earth’s magnetic reversals and the striping pattern. Following their break-through discovery, similar studies were repeated for other spreading centers.
How are magnetic stripes used to date rocks?
However, it was the potassium-argon dating method that unlocked the riddle of the magnetic striping on the ocean floor and provided convincing evidence for the seafloor spreading hypothesis. Cox and his colleagues used this method to date continental volcanic rocks from around the world.
When did vine and Matthews study magnetic stripes?
In 1966, Vine and Matthews — and also Morley working independently — compared these known ages of magnetic reversals with the magnetic striping pattern found on the ocean floor.