Evidence of Seafloor Spreading By April Carlisle and

Evidence of Seafloor Spreading By: April Carlisle and Stephen Loucks

Harry Hess Ø Ø Ø The surface of this planet is not fixed as it seems but rather broken up like pieces of a jigsaw puzzle. There are enormous plates that move under Earth, this process is called plate tectonic, and it transformed the thinking of geologist everywhere. One of them, Harry Hess, was a factor in figuring out how plate tectonics worked. In 1960, Harry Hess studied Wegner's theory. In 1962, as a result of oceanographic research conducted in the 1950’s Harry Hess proposed theory of seafloor spreading to account for continental movement. He suggested that continents do not move across oceanic crust, but rather that the continents and oceanic crust move together. Hem suggested that the seafloor separates at oceanic ridges and that new crust is formed by upwelling magma.

Alfred Wegner In 1912, he purposed the idea of continental drift , which he believed was true because of the different placement of animals, plants, fossils, and glacial deposit. Wegner's idea was not accepted by the scientific community at this time because there was little evidence to support his theory. In the late 1960’s there was a growing amount of evidence to support his idea, which is now widely excepted.

Evidence of Seafloor spreading

Showing rifting

Ø Seafloor spreading and other tectonic activity processes are the result of mantle convection. Mantle convection is the slow, churning motion of Earth’s mantle. Convection currents carry heat from the lower mantle and core to the lithosphere. Convection currents also “recycle” lithospheric materials back to the mantle. A rift valley is a large elongated depression with steep walls formed by the downward displacement of a block of the earth's surface between nearly parallel faults or fault systems.

Sonar is a technique that uses sound propagation to navigate, communicate with or detect objects on or under the surface of the water, such as other vessels. Sonar uses sound waves to see in the water when were up on land or in a boat. It is used to navigate the seafloor, it plays a big role in helping us understand how are seafloor is changing.

Instruments used to see the seafloor Magnetometer, an instrument used to measure the magnetic properties of the ocean floor. Satellites that detect and observe different characteristics and features of the Earth's atmosphere, lands, and ocean are often referred to as environmental satellites. Most environmental satellites have one of two types of orbits: geosynchronous or sun-synchronous. SOund NAvigation and Ranging—SONAR—is used to find and identify objects in water. It is also used to determine water depth. Sonar is applied to water-based activities because sound waves attenuate less in water as they travel than do radar and light waves.

Keeping earth in shape !!!!!! Seafloor spreading is just one part of plate tectonics. Subduction is another. Subduction happens where tectonic plates crash into each other instead of spreading apart. At subduction zones, the edge of the denser plate subducts, or slides beneath the less-dense one so, the denser lithospheric material then melts back into the Earth's mantle. Seafloor spreading creates new crust and subduction destroys old crust. The two forces roughly balance each other out, so the shape and diameter of the Earth remain constant.