Discuss the evidence for tectonic plate

Certainly there is no evidence that the moon has expanded in the past 3 billion years; other work would soon show that the evidence was equally in support of continental drift on a globe with a stable radius.

In terms of heat transfer, the lithosphere loses heat by conductionwhereas the asthenosphere also transfers heat by convection and has a nearly adiabatic temperature gradient. With increasing depth, however, the greater pressure from the weight of the rocks above causes the mantle to become gradually stronger, and seismic waves increase in velocity, a defining characteristic of the lower mantle.

These boundaries are discussed in Discuss the evidence for tectonic plate detail below. Let me look at this photograph right over here. Where this occurs, rare slices of ocean crust, known as ophiolitesare preserved on land.

Collectively, these studies show that Earth can be internally divided into layers on the basis of either gradual or abrupt variations in chemical and physical properties. So that by itself, that frankly is the most definitive evidence in the s where it kind of became conclusive that you did have these plates that were moving away from each other.

That's just a little Discuss the evidence for tectonic plate, but that by itself doesn't tell you that these plates are actually moving apart at the ridge. He named this supercontient Pangaea, and maitntianed that it had later split into to the two continents of Laurasia in the north and Gondwanaland in the south.

Mesosaurus only in southern Africa and in SA. Although it doesn't tell us that it's still moving or what might have caused the movement.

Geological Survey Many transform faults in the Atlantic Ocean are the continuation of major faults in adjacent continents, which suggests that the orientation of these faults might be inherited from preexisting weaknesses in continental crust during the earliest stages of the development of oceanic crust.

Subduction zones The subduction process involves the descent into the mantle of a slab of cold hydrated oceanic lithosphere about km 60 miles thick that carries a relatively thin cap of oceanic sediments. Cynognathus is an extinct mammal-like reptile. Mountain building If the rate of subduction in an ocean basin exceeds the rate at which the crust is formed at oceanic ridges, a convergent margin forms as the ocean initially contracts.

During these accretionary events, small sections of the oceanic crust may break away from the subducting slab as it descends. He concluded that tidal forces the tidal lag or "friction" caused by the Earth's rotation and the forces acting upon it by the Moon are a driving force for plate tectonics.

Biological evidence-same fossils on eithe side of Atlantic. For example, the Cordilleran mountain belt of North America —which includes the Rocky Mountains as well as the Cascadesthe Sierra Nevadaand other mountain ranges near the Pacific coast—developed by a combination of subduction and terrane accretion.

Cool oceanic lithosphere is significantly denser than the hot mantle material from which it is derived and so with increasing thickness it gradually subsides into the mantle to compensate the greater load. This would be the situation in a constant magnetic field.

Geologists maintain that the core is made up primarily of metallic iron accompanied by smaller amounts of nickelcobaltand lighter elements, such as carbon and sulfur.

This explains why ocean floor rocks are generally less than million years old whereas the oldest continental rocks are more than 4 billion years old.

Until the mids, ophiolites were thought to represent vestiges of the main oceanic tract, but geochemical analyses have clearly indicated that most ophiolites form near volcanic arcs, such as in back-arc basins characterized by subduction roll-back the collapse of the subducting plate that causes the extension of the overlying plate.

The Coriolis force [24] [25] The centrifugal forcewhich is treated as a slight modification of gravity [24] [25]: The speed of the plate can be inferred from the increase in age of the volcanoes along the chain relative to the distance between the islands.

Mountains by continental collision Continental collision involves the forced convergence of two buoyant plate margins that results in neither continent being subducted to any appreciable extent. And, using the mobilistic concepts developed before, he correctly concluded that many millions of years later, the oceanic crust eventually descends along the continental margins where oceanic trenches — very deep, narrow canyons — are formed, e.

Plate tectonics

Data from alternative models suggest that many plumes are not deep-rooted. The balance between creation and destruction on a global scale is demonstrated by the expansion of the Atlantic Ocean by seafloor spreading over the past million years, compensated by the contraction of the Pacific Oceanand the consumption of an entire ocean between India and Asia the Tethys Sea.

Plate tectonics describes seismic activity,… The theory of plate tectonics is based on a broad synthesis of geologic and geophysical data. Maybe this is just a coincidence that this coast of South America looks very similar to this coast right here of Africa.

The addition of water lowers the melting point of the mantle material above the subducting slab, causing it to melt. Divergence and creation of oceanic crust are accompanied by much volcanic activity and by many shallow earthquakes as the crust repeatedly rifts, heals, and rifts again. Because of the enormous angular momentum of the Earth and the absence of a source of torque to change that angular momentum, we can presume that the spin axis has remained essentially constant in space.

The study of global seismicity greatly advanced in the s with the establishment of the Worldwide Standardized Seismograph Network WWSSN [45] to monitor the compliance of the treaty banning above-ground testing of nuclear weapons. Because it is formed at mid-ocean ridges and spreads outwards, its thickness is therefore a function of its distance from the mid-ocean ridge where it was formed.This was taken as evidence that the magnetic poles "wandered" over the surface of the Earth.

But given the stability of the Earth's rotation axis and it's association with the magnetic field generation as discussed above, it seems more likely that the land mass itself had. Glacial evidence Widespread distribution of Permo-Carboniferous glacial sediments in South America, Africa, Madagascar, Arabia, India, Antarctica and Australia was one of the major pieces of evidence for the theory of continental drift.

Plate tectonics: Evidence of plate movement

Glacial evidence. Widespread distribution of Permo-Carboniferous glacial sediments in South America, Africa, Madagascar, Arabia, India, Antarctica and Australia was one of the major pieces of evidence for the theory of continental drift.

Plate tectonics

Plate tectonics is an interpretation or model of what geologists envisage happened to these plates through earth’s history Catastrophic Breakup Plate tectonics is not directly mentioned in the Bible, but Genesis –10 suggests that all of the land was once connected, whereas the.

Evidence of this is shown at mid-ocean ridges where younger land is pushed up through the ridge, causing the older land to move out and away from the ridge, thus moving the tectonic plates. Gravity is a secondary driving force for the movement of the Earth's tectonic plates. Image: From This Dynamic Earth: The Story of Plate Tectonics p8 Remains of Mesosaurus, a freshwater crocodile-like reptile that lived during the early Permian (between and million years ago), are found solely in Southern Africa and Eastern South America.

Discuss the evidence for tectonic plate
Rated 3/5 based on 45 review