What is the main idea behind magnetic anomaly detectors?
A magnetic anomaly detector (MAD) is an instrument used to detect minute variations in the Earth’s magnetic field.
What did marine magnetic anomalies prove?
These anomalies provided the convincing evidence for plate tectonics and the resulting revolution in the earth sciences. In addition to the intensity of the field, we can measure two angular components of the field vector: The declination measures the direction to the north magnetic pole.
How did drilling samples show that sea floor spreading really has taken place?
Samples from the sea floor were brought up through the pipes. Then the scientists determined the age of the rocks in the samples. They found that the farther away from the ridge the samples were taken, the older the rocks were. This showed that sea- floor spreading really has taken place.
Why is it important that your model have an identical pattern of stripes on both sides of the center slit?
Why is it important that your model have an identical pattern of strips on both sides of the center slit? The model has identical strips because, as the magma rises at the mid ocean ridge ½ goes to the right and ½ goes to the left of the mid ocean ridge. Each one of these strips represents Earth’s magnetic history.
What do side slits stand for?
where subduction has occurred
Where is the famous seafloor spreading site?
mid-ocean ridge
What is your description of the pattern of stripes on both sides left and right of the mid-ocean ridge?
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.
Which boundaries is seafloor destroyed?
You are correct that the seafloor is destroyed at subduction zones, but it is simultaneously being created at mid-ocean ridges. see figure 1 . Figure 1: Seafloor spreading at a mid-ocean ridge(where new crust is being created) and it’s destruction at a subduction zone.
What causes the formation of new seafloor?
Explanation: Seafloor spreading is a process that occurs at mid-ocean ridges, where new oceanic crust is formed through volcanic activity and then gradually moves away from the ridge.At a spreading center, basaltic magma rises up the fractures and cools on the ocean floor to form new seabed.
How is seafloor formed?
As plates converge, one plate may move under the other causing earthquakes, forming volcanoes, or creating deep ocean trenches. Where plates diverge from each other, molten magma flows upward between the plates, forming mid-ocean ridges, underwater volcanoes, hydrothermal vents, and new ocean floor crust.
What is the seafloor made of?
Known as manganese nodules, they are composed of layers of different metals like manganese, iron, nickel, cobalt, and copper, and they are always found on the surface of the ocean floor.
What are three evidences that support seafloor spreading?
Harry Hess’s hypothesis about seafloor spreading had collected several pieces of evidence to support the theory. This evidence was from the investigations of the molten material, seafloor drilling, radiometric age dating and fossil ages, and the magnetic stripes.
What adds more crust to the ocean floor?
As the molten material cools, it forms a strip of solid rock in the center of the ridge. Then more molten material splits apart the strip of solid rock that formed before, pushing it aside. This process, called sea-floor spreading, continually adds new material to the ocean floor.