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Hot material ascends at the ridge axis form the mantle. It partially melts. The basaltic melts ascend and form 6-7 km of oceanic crust. The seafloor and the underlying mantle then move away from the ridge axis. The material cools from top down. As it does it contracts thermally and becomes more dense. The vertical contraction of the material and the increased load on the underlying mantle causes the seafloor to subside. The weight of the overlying water also causes subsidence. To the first order, the predicted depth to the seafloor increases with the square root of age from the ridge axis. This in fact occurs and was strong evidence for the reality of seafloor spreading in the late 1960s. Note that Lord Kelvin was on the trans-Atlantic cable project. He crossed the Charlie-Gibbs fracture zone rather than the ridge axis. The square-root relationship was not evident. Wegener also considered the process to some extent, but ended up with continents moving as rafts rather than with seafloor spreading.
See paper for technical derivation and some early references.
2011 Sleep, N. H., Small-scale convection beneath oceans and continents. Chi. Sci. Bull., 56(13), 1292-1317, DOI: 10.1007/s11434-011-4435-x.
What else can I help you with?
Why does the temperature decrease as elevation increases?
The heat of the earth escapes through the atmosphere into outer space. Greenhouse gases interfere with/ clog up that process. The higher up in the atmosphere, the colder it is. So it is colder at higher elevations. Also, the low air pressure a sparsity of air particles cause the air to be thinner and colder
What are the examples of divergent boundary?
Examples of a divergent boundary would be a mid-ocean ridge. Two plates are pulling apart from each other. If you have heard before, the magma from the asthenosphere find a way to get out through the crack of the diverging plates and makes new land. Another type of devergent boundary would be a fissure. It is a long linear crack made by the plates moving apart. I think maybe another one would probably be a volcano, but I am not sure.
An underwater mountain chain that formed by sea-floor spreading is called a?
Underwater mountain chains that form where two tectonic plates are pulling apart are called mid ocean ridges. The largest is the Mid Atlantic Ridge.
Is Greenland moving farther away from France?
Greenland sits on the North American tectonic plate, and France sits on the Eurasian plate. These are two large fragments of the Earth's crust (or the lithosphere to be more correct). All plates are constantly moving, and there is a general drift caused by the circulation of heat in the mantle (or asthenosphere). The general trend currently is for the North American and Eurasian plates to move away from each other, the line along which this movement happens is marked by the Mid-Atlantic Ridge. So, Greenland is moving away from France, but only by a few millimetres per year.
As water gets denser how does it moves?
Water increases in density until 4 degrees Celcius, when its density starts to decrease again due to hydrogen bonding. (see Wikipedia.org for more.) As water moves away from the equator, it gives off heat. As it cools, its density increases.
True or false sea floor sediments gradually thicken away from a mid-ocean ridge?
False. Sea floor sediments do not gradually thicken away from a mid-ocean ridge. Instead, the thickness of sediments can vary significantly depending on factors such as proximity to sources of sediment input, ocean currents, and tectonic activity.
Why does oceanic crust get colder away from ridges?
Oceanic crust gets colder away from mid-ocean ridges due to the cooling of the newly formed basaltic rock as it moves away from the heat source. As magma rises and solidifies at the ridge, it forms hot, young crust that gradually loses heat as it is transported laterally by tectonic plate movement. Additionally, the increasing distance from the ridge allows for more time for heat dissipation into the surrounding ocean water, leading to a decrease in temperature. Thus, the oceanic crust becomes progressively colder and denser with increasing distance from the ridge.
How does evidence that rocks farther from a ridge are older than rocks closer to the ridge support the idea of sea floor spreading?
The evidence that rocks farther from a ridge are older than rocks closer to the ridge supports the idea of sea floor spreading because it aligns with the concept of a divergent boundary where new oceanic crust is continuously formed at the ridge and gradually moves away from the ridge over time. This process allows for the creation of age gradients in the oceanic crust, with the youngest rocks found near the ridge and progressively older rocks located farther away.
What happens to land elevation as you move inland?
As you move inland from the coast, land elevation tends to increase. This is because coastal areas are often low-lying due to deposition of sediment from rivers and the sea, while inland areas are usually further away from these sources and are less affected by erosion and sedimentation. Therefore, land elevation generally rises as you move away from the coast.
Why are oceans far away form a ridge?
cuz rocks come up from the ridge and create land by the ridge
When examining rocks from both sides of the mid Atlantic ridge scientists found evidence for?
When examining rocks from both sides of the Mid-Atlantic Ridge, scientists found evidence of symmetric patterns of magnetic striping and varying ages of rocks. This indicated that new oceanic crust is formed at the ridge and gradually moves away from it, supporting the theory of seafloor spreading. Additionally, the rocks showed differences in composition and age, with younger rocks closest to the ridge and older rocks further away, reflecting the dynamic processes of plate tectonics.
Which way is New York moving in relation to the mid Atlantic ridge?
New York is moving northwestward in relation to the Mid-Atlantic Ridge. The Mid-Atlantic Ridge is a divergent tectonic plate boundary where the Eurasian and North American plates are moving apart. As these plates separate, New York, located on the North American Plate, is gradually shifting away from the ridge. This movement is part of the broader geological processes associated with plate tectonics.
Does the farther from a mid-ocean ridge a rock is a sample is taken the younger the rock is?
No, the farther from a mid-ocean ridge a rock sample is taken, the older the rock generally is. Mid-ocean ridges are sites of seafloor spreading, where new oceanic crust is formed as magma rises and cools. As tectonic plates move away from the ridge, the rocks gradually age, making those farther from the ridge older than those closer to it.
Why does the lithosphere thicken away from the ridge crest?
Cooling as rock moves away from the ridge crest causes the rock to become increasingly rigid.
How is crust created at the oceanic ridge?
Mid-ocean ridges are a line of volcanic mountains under the oceans between the continents. As the oceanic plates are being pulled apart by the processes of plate tectonics, magma is formed from decompression melting in the mantle, and rises upward to fill in the gap that is created. Because this material solidifies and is still hot, it is buoyant and rises higher than the surrounding seafloor, creating the ridges. As it is pulled away from the spreading point by plate tectonics, it gradually cools, making it less buoyant; it gradually drops in elevation.
What a ridge push?
Ridge push is a gravitation force that causes a plate to move away from the crest of an ocean ridge, and into a subduction zone.
What is a sentence for Ridge?
The only way to the northern valley was across the intervening ridge. You can fold a ridge into your paper to prevent your pencil from rolling away.
