What is normal and reversed polarity?

The polarity can be “normal” or “reversed.” Normal polarity is where the magnetic north points (roughly) towards the geographic north pole. Reversed polarity is in the opposite direction, and the north end of the magnetic field is close to the present-day south pole.

What does reversed polarity mean in the seafloor spreading theory?

A polarity reversal means that the magnetic North flips to where we know the South Pole is. 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.

What is the purpose of seafloor spreading?

Significance. Seafloor spreading helps explain continental drift in the theory of plate tectonics. When oceanic plates diverge, tensional stress causes fractures to occur in the lithosphere.

What is sea floor spreading and how does it work what happens what kind of boundary does it take place in?

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 does normal polarity mean?

(a) A natural remanent magnetization closely parallel to the present ambient geomagnetic field direction. (b) A configuration of the Earth’s magnetic field with the magnetic negative pole, where field lines enter the Earth, located near the geographic south pole.

Is normal polarity positive?

The positive direction of magnetization of a rock is, by definition, its “north-seeking magnetization” (it points toward the Earth’s present magnetic North Pole), and the rock is said to have “normal agnetization”, or “normal polarity”.

When scientists plotted the points of normal and reversed polarity on a seafloor map what type of pattern did they discover in the magnetic polarity?

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.

How do sea floor spreading and volcanic hotspots are related?

Seamounts are individual volcanoes on the ocean floor. Large seamounts are often fed by “hot spots” in the deep mantle. These hot spots are associated with plumes of molten rock rising from the deep within the Earth’s mantle. These hot spot plumes melt through the overlying tectonic plate and supply magma to seamounts.

How does seafloor spreading move the continents?

Seafloor spreading creates new oceanic crust at a mid-ocean ridge. On one side, the oceanic crust is subducted below the continental crust. On the other side, the two plates collide in a transform boundary, which is a horizontal type of movement. The latter is the closest we really come to continents drifting.

Is sea floor spreading convergent?

The tectonic plates are constantly moving together (convergent boundary), apart (divergent boundary), and past each other (transform boundary). At mid-ocean ridges, tectonic plates move apart and seafloor spreading occurs. Seafloor spreading is the process by which new oceanic lithosphere forms at mid-ocean ridges.

How do ocean ridges and deep sea trenches support the theory of seafloor spreading?

New crust can be observed being formed on the sea floor ridges. Matching magnetic lines of reversal along both sides of the ocean ridge also lends support to the theory of sea floor spreading. The subduction zones which form the deep sea trenches also support the theory of sea floor spreading.

What is an example of normal polarity?

What was the polarity of the ocean floor closest to the ridge?

What they noticed was that the stripe of ocean floor closest to the ridge had normal polarity, but the next stripe out revealed reverse polarity. This alternating pattern continued the farther the investigators got from the ridge.

What is sea floor spreading and how does it work?

Sea floor spreading is the process by which new oceanic crust is formed by the upwelling of magma through diverging tectonic plates. Imagine you are a scientist living in the 1800s. The first somewhat useful submarines were starting to appear, yet these early vessels were not well-suited for exploring the tremendous depths of the oceans.

What is the difference between sea floor spreading and mantle convection?

Seafloor spreading is a geologic process in which tectonic plates—large slabs of Earth’s lithosphere—split apart from each other. Seafloor spreading and other tectonic activity processes are the result of mantle convection. Mantle convection is the slow, churning motion of Earth’s mantle.

How do diverging tectonic plates affect the ocean floor?

These diverging tectonic plates created a gap in the ocean floor where magma, which is hot molten rock from the hotter and deeper layers of the earth, could escape. This hot molten rock would cool when it came in contact with the ocean waters to form new rock on the ocean floor.