- When was Harry Hess born?
- When was the seafloor spreading discovered?
- Who first discovered seafloor spreading and what was the new technology used?
- What is the main cause of seafloor spreading?
- Where does seafloor spreading occur?
- What are the steps in the process of seafloor spreading?
- What causes the plates to move?
- How fast do tectonic plates move?
- How old is the seafloor?
- Who discovered magnetic striping?
- What is evidence of seafloor spreading?
- How was seafloor spreading discovered?
- Where is the oldest seafloor found?
- Can divergent boundaries cause volcanoes?
- Which boundary is seafloor destroyed?
- How old is the youngest seafloor?
- What is the average speed of seafloor spreading?
- What are magnetic anomalies on the ocean floor?
- What is magnetic striping of the ocean floor?
- What is the major evidence that seafloor spreading creates new lithosphere?
- How is paleomagnetism evidence of seafloor spreading?
- Does the Earth get bigger because of seafloor spreading?
- What causes magnetic striping on the sea floor?
When was Harry Hess born?
May 24, 1906Harry Hammond Hess/Date of birthHarry Hammond Hess (May 24, 1906-August 25, 1969) was an American geologist.
Considered one of the “founding fathers” of the unifying theory of plate tectonics, Rear Admiral Dr.
Harry Hammond Hess was born on May 24, 1906 in New York City..
When was the seafloor spreading discovered?
1960The seafloor spreading hypothesis was proposed by the American geophysicist Harry H. Hess in 1960.
Who first discovered seafloor spreading and what was the new technology used?
Alfred Wegener produced evidence in 1912 that the continents are in motion, but because he could not explain what forces could move them, geologists rejected his ideas. Almost 50 years later Harry Hess confirmed Wegener’s ideas by using the evidence of seafloor spreading to explain what moved continents.
What is the main cause of 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.
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.
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.
What causes the plates to move?
The plates can be thought of like pieces of a cracked shell that rest on the hot, molten rock of Earth’s mantle and fit snugly against one another. The heat from radioactive processes within the planet’s interior causes the plates to move, sometimes toward and sometimes away from each other.
How fast do tectonic plates move?
They move at a rate of one to two inches (three to five centimeters) per year.
How old is the seafloor?
150 million yearsVery little of the sea floor is older than 150 million years. This is because the oldest sea floor is subducted under other plates and replaces by new surfaces. The tectonic plates are constantly in motion and new surfaces are always being created.
Who discovered magnetic striping?
Vine and Matthews noticed there was a symmetrical pattern of magnetic stripes on either side of the mid ocean ridges. In addition when the basalts of the sea floor were dated, they were found to be the same age at similar distances away from the ridge on each side.
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 was seafloor spreading discovered?
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.
Where is the oldest seafloor found?
Mediterranean SeaThe oldest seafloor is comparatively very young, approximately 280 million years old. It is found in the Mediterranean Sea and is a remnant of an ancient ocean that is disappearing between Africa and Europe.
Can divergent boundaries cause volcanoes?
Most volcanoes form at the boundaries of Earth’s tectonic plates. … The two types of plate boundaries that are most likely to produce volcanic activity are divergent plate boundaries and convergent plate boundaries. Divergent Plate Boundaries. At a divergent boundary, tectonic plates move apart from one another.
Which boundary is seafloor destroyed?
subduction zonesYou 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.
How old is the youngest seafloor?
Because of this correlation between age and subduction potential, very little ocean floor is older than 125 million years and almost none of it is older than 200 million years.
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 are magnetic anomalies on the ocean floor?
study of oceanic crust A marine magnetic anomaly is a variation in strength of Earth’s magnetic field caused by magnetism in rocks of the ocean floor. Marine magnetic anomalies typically represent 1 percent of the total geomagnetic field strength.
What is magnetic striping of the ocean floor?
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.
What is the major evidence that seafloor spreading creates new lithosphere?
When the Earth’s magnetic field reverses, the magnetized minerals align in the opposite direction. The record of magnetic reversals is carried away from each side of the spreading center of a mid-ocean ridge, showing that the molten rock is creating new lithosphere.
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.
Does the Earth get bigger because of seafloor spreading?
New crust is continually being pushed away from divergent boundaries (where sea-floor spreading occurs), increasing Earth’s surface. But the Earth isn’t getting any bigger.
What causes magnetic striping on the sea floor?
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.