What Explains The Age And Magnetic Patterns Of Sea Floor Rocks?

Why are magnetic patterns important?

These patterns of stripes provide the history of seafloor spreading.

Geophysicists can read these patterns from the magnetic anomalies they measure with a magnetometer.

Where the magnetic wiggles, or anomalies, are broader, the spreading rate has been faster..

What is evidence of seafloor spreading?

Several types of evidence supported Hess’s theory of sea-floor spreading: eruptions of molten material, magnetic stripes in the rock of the ocean floor, and the ages of the rocks themselves. This evidence led scientists to look again at Wegener’s hypothesis of continental drift.

How magnetic symmetry can be used as evidence of seafloor spreading?

Explanation: Magnetic symmetry was the first evidence that lead to the theory of sea floor spreading. During World War II submarine warfare caused the intense study of magnetism on the ocean floor. The magnetic symmetry made spotting local abnormalities like a steel submarine easier to spot.

What is magnetic striping on the seafloor?

Magnetic striping – Magnetic minerals are found in rocks. … But once the magma solidifies, the minerals are locked into place and as such can record the reversals of Earth’s magnetic field. The result of this is stripes of magnetic minerals that parallel the mid-ocean ridges.

How is magnetic striping evidence of plate tectonics?

During times of normal magnetic polarity, the rocks being created stayed normal. … If they were created during times of reverse polarity, the rocks would freeze that magnetic orientation in place.

What is the significance of magnetic patterns on the seafloor?

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.

What has caused the zebra pattern in the rock of the ocean floor?

What has caused the “zebra” pattern in the rock of the ocean floor? A magnetic reversal happens. … Rocks makes up the seafloor has iron in it and as the mid ocean ridge cools little pieces of iron “line up” with Earth’s magnetic field and then they stay like the magnetic field is preserved and the seafloor spread.

What are the steps in the process of seafloor spreading?

What are the steps in the process of sea floor spreading?Magma comes out of the rift valley.Magma cools to rock and hardens.Rock is pushed away as new rock is formed at MOR.Oceanic crust and continental crust meet at the trench.Oceanic crust bends down under the continental crust.Gravity pulls rock towards mantle.Rock melts to mantle.

Why is the ocean floor not flat?

The difference is sea level is caused by two major factors: tides and ocean currents. Tides are mainly caused by the gravitational pull of the Moon and the Sun, acting on the Earth’s surface. Ocean currents are caused by winds and a mixing of waters with different densities.

What is a device that scientists use to map the ocean floor?

Dive and Discover : Oceanographic Tools: Sonar. Echo sounding is the key method scientists use to map the seafloor today. The technique, first used by German scientists in the early 20th century, uses sound waves bounced off the ocean bottom.

How is the age of the seafloor determined?

To confirm the ages obtained with magnetic records, and get an absolute age of the seafloor, scientists use the radioactive dating technique. When the lava solidifies at the ridges to form the new seafloor, radioactive elements coming from the mantle are trapped in it.

Where does seafloor spreading occur?

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.

Are tectonic plates magnetic?

Over the next few decades, science found more evidence Wegener was right. Plate tectonics — the concept the continents are rock plates moving on the magma underneath — is now accepted. Magnetism is part of the evidence for plate tectonic theory.

How do 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. … Later, after the planet’s magnetic field flips again, the next stripe of new ocean floor aligns its polarity in the opposite direction.

What is the effect of seafloor spreading?

Mid-ocean ridges and seafloor spreading can also influence sea levels. As oceanic crust moves away from the shallow mid-ocean ridges, it cools and sinks as it becomes more dense. This increases the volume of the ocean basin and decreases the sea level.

What are the 4 evidence of continental drift?

They based their idea of continental drift on several lines of evidence: fit of the continents, paleoclimate indicators, truncated geologic features, and fossils.

What pattern can be found on the seafloor?

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.

How often do magnetic reversals occur?

‘ Reversals are the rule, not the exception. Earth has settled in the last 20 million years into a pattern of a pole reversal about every 200,000 to 300,000 years, although it has been more than twice that long since the last reversal.