Different seafloor magnetic stripes equal different ages. By using geologic dating techniques, scientists could figure out what these ages are. They found that the youngest rocks on the seafloor were at the mid-ocean ridges. The rocks get older with distance from the ridge crest.
How is the magnetic polarity shown on the ocean floor?
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.
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.
Can you see the magnetic stripes on the sea 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 do magnetic stripes on the ocean floor serve as 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.
Why were magnetic patterns found on the ocean floor puzzling?
Why were magnetic patterns found on the ocean floor puzzling? They showed alternating bands of normal and reversed polarity. No rocks were magnetic. They did not show alternating bands of normal and reversed polarity.
What observations did scientists make in the 1950s about the magnetic polarity of rocks?
Magnetic latitude ” the paleomagnetic inclination is therefore a record of the place between the pole and the equator where the rock was formed. Apparent Polar Wander ” Geophysicists studying paleomagnetic pole positions during the 1950s found evidence suggesting that poles wandered all over the globe.
What does magnetic stripe pattern mean?
They occur in stripes that parallel mid-ocean ridges and are offset along transform faults. The seafloor’s permanent magnetic signatures showed that new ocean crust was created at the ridge crests and then spread outward in both directions. rift in underwater mountain range where new oceanic crust is formed.
Where would you expect to see alternating bands of rock with different magnetic polarities?
Answer and Explanation: You would expect to see alternating bands of rock with different magnetic polarities on the ocean floor extending out from a mid-oceanic ridge.
What is magnetic polarity?
magnetic polarity (countable and uncountable, plural magnetic polarities) (physics) the state of being a north pole or south pole; the magnetic equivalent of electric charge.
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 when Earth’s poles reversed. They show how the density of the seafloor has changed.
Why does the sea floor have a striped pattern of magnetic anomalies that is symmetric with respect to the mid-ocean ridge?
Why does the sea floor have a striped pattern of magnetic anomalies that is symmetric with respect to the mid-ocean ridge? “The polarity of Earth’s magnetic field experiences reversals. -The igneous rock of the ocean floor preserves Earth’s existing magnetic field as the rock cools.
What creates magnetic stripes on the seafloor quizlet?
Why does the rock of the ocean floor have a pattern of magnetic stripes? 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 is the difference between normal polarity and reversed polarity?
The polarity can be “normal” or “reversed.” Normal polarity is where the magnetic north points (roughly) towards the geographic north pole. This is how the magnetic field is aligned today. Reversed polarity is in the opposite direction, and the north end of the magnetic field is close to the present-day south pole.
What evidence helps scientists show how seafloor spreading occurs?
The age of Earth’s oceanic crust can be presented to show the pattern of seafloor spreading at the global scale. Encyclopædia Britannica, Inc. Measurements of the thickness of marine sediments and absolute age determinations of such bottom material have provided additional evidence for seafloor spreading.
What evidence was found by geophysicist about magnetic patterns found on the ocean floor?
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.
What did Scientist find while studying the ocean floor?
Harry Hess was a geologist and Navy submarine commander during World War II. Part of his mission had been to study the deepest parts of the ocean floor. In 1946 he had discovered that hundreds of flat-topped mountains, perhaps sunken islands, shape the Pacific floor.
What did scientists observe when they studied the magnetic fields of rocks on the sides of mid-ocean ridges?
When scientists studied the magnetic properties of the seafloor, they discovered normal and reversed magnetic stripes with different widths. These magnetic patterns are parallel to the mid-ocean ridges and symmetrical on both sides.
Where can scientists see clear evidence in the ocean that Earth’s magnetic field has flipped many times in its history?
As a matter of geological record, the Earth’s magnetic field has undergone numerous reversals of polarity. We can see this in the magnetic patterns found in volcanic rocks, especially those recovered from the ocean floors.
How did scientists use magnetic evidence to conclude that the continents moved?
Scientists used magnetometers to show where the north magnetic pole had been when magnetite crystals cooled. Magnetite crystals of different ages and on different continents pointed to different spots. The simplest explanation is that the continents have moved.
When was evidence of continental drift from magnetic polarity?
Using magnetic evidence found on a single continent in the 1950s, scientists showed that either the north magnetic pole was in a different spot in Earth’s past or that the continents had moved.
Why are some magnetic anomaly stripes wider than others?
Knowing what you know about sea-floor spreading and magnetic reversals, suggest an explanation. I would suggest that some stripes are wider than others because during the formation of new lithosphere, more molten material could have came out of the asthenosphere than during the previous spread cycle.
How are magnetic reversals recorded in rocks?
A reversal occurs only when the magnetic field orientation changes to the opposite direction. Past reversals of the magnetic field are recorded in the rocks. Many rocks contain iron-bearing minerals that act as tiny magnets. As magma or lava cool, these minerals begin to form.
Why are the magnetic lineations identical on either side of the mid-ocean ridge?
Why are the magnetic lineations identical on either side of the mid-ocean ridge? New ocean crust is moving laterally and uniformly away from the ridge in TWO equal/opposite directions ” new crust is produced and moves perpendicularly away from the ridge. -As the crust cools, it acquires the prevailing magnetic field.
How are Earth’s geographic and magnetic axis oriented relative to each other?
How are Earth’s geographic and magnetic axes oriented relative to each other? Earth’s geographic and magnetic axes are oriented at a slight angle to each other.
How often does Earth’s magnetic field switch polarity quizlet?
Earth’s magnetic field switches polarity at irregular time intervals. How often does the Earth’s magnetic field switch polarity? Every 100,000 to several million years.
Where do both earthquakes and volcanic eruptions occur?
In general, where do earthquakes AND volcanic eruptions occur? In general,earthquakes and volcanic eruptions occur at both divergent plate boundaries AND convergent plate boundaries.
How are the polarity of the magnet and the polarity of the voltage related explain?
The magnitude of the voltage is proportional to the rate of change of magnetic flux in the coil, so that moving the magnet in faster will produce a greater voltage. The polarity of the voltage is such that it opposes the change that produces it, so pulling the magnet out will produce a voltage of the opposite polarity.
What are magnetic polarity reversals?
A magnetic polarity reversal is a change of the earth’s magnetic field to the opposite polarity. This has occurred at irregular intervals during geologic time.
What indicators were observed by geologist to conclude that the polarity is reversed?
We can see evidence of magnetic polarity reversals by examining the geologic record. When lavas or sediments solidify, they often preserve a signature of the ambient magnetic field at the time of deposition. Incredible as it may seem, the magnetic field occasionally flips over!
How do magnetic stripes of iron in ocean rock Brainly?
Answer: They show how the density of the sea floor has changed. They reveal a matching pattern on either side of the ridge . They reveal differences in the mineral composition of newly created rock.
Why magnetic stripes in the Pacific Ocean are wider than in the Atlantic Ocean?
Magnetic stripes in the Pacific Ocean are wider because the seafloor spreads more rapidly there than in the Atlantic Ocean.
Which statement accurately describes how magnetic stripes in ocean rock provide evidence of seafloor spreading Brainly?
Which statement accurately describes how magnetic stripes in ocean rock provide evidence of seafloor spreading? C. The pattern of magnetic strips shows that the seafloor is expanding at mid-ocean ridges.
How do magnetic stripes form on the ocean floor Why are these stripes significant?
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.
What does magnetic stripe pattern mean?
They occur in stripes that parallel mid-ocean ridges and are offset along transform faults. The seafloor’s permanent magnetic signatures showed that new ocean crust was created at the ridge crests and then spread outward in both directions. rift in underwater mountain range where new oceanic crust is formed.
What happens during sea floor spreading?
Sea-floor spreading is what happens at the mid-oceanic ridge where a divergent boundary is causing two plates to move away from one another resulting in spreading of the sea floor. As the plates move apart, new material wells up and cools onto the edge of the plates.
How does sea floor spreading explain the features of mid-ocean ridges?
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.
When Earth’s magnetic field changes polarity between normal and reversed?
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.
Where would you expect to see alternating bands of rock with different magnetic polarities?
Answer and Explanation: You would expect to see alternating bands of rock with different magnetic polarities on the ocean floor extending out from a mid-oceanic ridge.
Why were magnetic patterns found on the ocean floor puzzling?
Why were magnetic patterns found on the ocean floor puzzling? They showed alternating bands of normal and reversed polarity. No rocks were magnetic. They did not show alternating bands of normal and reversed polarity.
What are two pieces of evidence for seafloor spreading?
Several types of evidence from the oceans supported Hess’s theory of sea-floor spreading-evidence from molten material, magnetic stripes, and drilling samples.
What is the evidence from magnetic stripes?
The magnetic stripes end abruptly at the edges of continents. Sometimes the stripes end at a deep sea trench (Figure below). Scientists found that magnetic polarity in the seafloor was normal at mid-ocean ridges but reversed in symmetrical patterns away from the ridge center.
Which is the rock type that scientists studied to discover magnetic striping?
Magnetic striping and polar reversals This finding, though unexpected, was not entirely surprising because it was known that basalt ” the iron-rich, volcanic rock making up the ocean floor” contains a strongly magnetic mineral (magnetite) and can locally distort compass readings.
What did scientists conclude when they discovered that stripes of ocean floor?
When scientists studied the magnetic properties of the seafloor, they discovered normal and reversed magnetic stripes with different widths. These magnetic patterns are parallel to the mid-ocean ridges and symmetrical on both sides.
What is the magnetic pattern of ocean floor rocks on one side of an ocean ridge?
The positive and negative areas of the seafloor form a series of stripes that were parallel to ocean ridges. The magnetic pattern on one side of the ridge is a mirror image of the pattern on the other side of the ridge.