Who Discovered Seafloor Spreading?

What do the side slits represent?

The side slits stand for old crust sinking back into the mantle of the Earth.

The space under the paper stands for the stands for the mantle itself.

3.) How does the ocean floor as shown by the part of the strip close to the center slit differ from the ocean floor as shown by the part near the side slit?.

What happens when two oceanic plates collide?

When two oceanic plates converge, the denser plate will end up sinking below the less dense plate, leading to the formation of an oceanic subduction zone. … Old, dense crust tends to be subducted back into the earth. An example of a subduction zone formed from a convergent boundary is the Chile-Peru trench.

What has been the average rate and direction of seafloor spreading in cm per year?

The average rate is 2.875 cm/yr and the direction is South east.

How old is the youngest seafloor?

The data is from four companion digital models of the age, age uncertainty, spreading rates and spreading asymmetries of the world’s ocean basins. Scientists use the magnetic polarity of the sea floor to determine the age. Very little of the sea floor is older than 150 million years.

Who first discovered seafloor spreading?

Harry HessHarry 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 is the difference between continental drift and seafloor spreading?

Continental drift is a very similar process to seafloor spreading. Continental drift is the gradual movement of continental plates over the Earth’s surface over time. … Seafloor spreading is the formation of new areas of oceanic crust due to the upwelling of magma as oceanic aparts pull apart.

Which is the first step in the seafloor spreading process?

1. A long crack in the oceanic crust forms at a mid ocean ridge. 2. Molten material rises and erupts along the ridge.

Who were the two scientists who proposed the theory of seafloor spreading?

The idea that the seafloor itself moves and also carries the continents with it as it spreads from a central rift axis was proposed by Harold Hammond Hess from Princeton University and Robert Dietz of the U.S. Naval Electronics Laboratory in San Diego in the 1960s.

Which boundaries is seafloor destroyed?

The seafloor is destroyed at a COnvergent Boundary.

Where is active seafloor spreading occurring today?

Where is active sea floor spreading occurring today? Seafloor spreading is the movement of old rock that is being pushed by the new young oceanic crust. This would be a divergent since the plates are separating from each other. Active seafloor spreading is occurring at mid-ocean ridges.

How do scientist were able to detect the features on the ocean seafloor?

Scientists can determine the age of the seafloor by examining the changing magnetic field of our planet. … While it cools down, it records the magnetic field during its formation. The two parts of the oceanic plate are pulled apart, and magnetic stripes become older as they move away from the mid-ocean ridge.

What is the average speed of seafloor spreading?

approximately 5 centimeters a yearThe average speed of seafloor spreading is approximately 5 centimeters a year. This growth rate can be compared to the growth rate of human fingernails (Krupicka). The global ridge system consists of oceanic ridges. Seafloor spreading occurs at these elevated oceanic ridges and has high heat flow and volcanism.

What kind of rock is the seafloor made of?

igneous rockAs old oceanic crust is subducted and melted into magma, new oceanic crust in the form of igneous rock is formed at mid-ocean ridges and volcanic hotspots.

What causes seafloor spreading?

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. Eventually, the crust cracks.

What is the evidence of seafloor spreading?

Abundant evidence supports the major contentions of the seafloor-spreading theory. First, samples of the deep ocean floor show that basaltic oceanic crust and overlying sediment become progressively younger as the mid-ocean ridge is approached, and the sediment cover is thinner near the ridge.

When did seafloor spreading start?

1960The seafloor spreading hypothesis was proposed by the American geophysicist Harry H. Hess in 1960.

What are the three types of seafloor spreading?

There are three types of plate-plate interactions based upon relative motion: convergent, where plates collide, divergent, where plates separate, and transform motion, where plates simply slide past each other.

What drives the plates to move around?

Tectonic shift is the movement of the plates that make up Earth’s crust. … The heat from radioactive processes within the planet’s interior causes the plates to move, sometimes toward and sometimes away from each other. This movement is called plate motion, or tectonic shift.

Where did Harry Hess go to school?

Princeton UniversityHarry Hammond Hess/Alma maters

How is paleomagnetism evidence of seafloor spreading?

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.

How did Harry H Hess discover seafloor spreading?

Hess discovered that the oceans were shallower in the middle and identified the presence of Mid Ocean Ridges, raised above the surrounding generally flat sea floor (abyssal plain) by as much as 1.5 km. … This created new seafloor which then spread away from the ridge in both directions.