Mantle dynamics, gravity, and Earth's rotation taken altogether causes the plate movements. However, convectional currents are the general thought for the motion.

I also introduce you to Dr Rajneesh Bhutani (https://www.researchgate.net/profile/Rajneesh_Bhutani2/) who can be the best man to answer this !

Hi Pawan........

As for as I understand the asthenosphere is weakly coupled to the lithosphere and has little effect on its motions. Beneath the interior of an oceanic plate, asthenosphere moves towards ridge, where as around the plate margins the asthenosphere flows into or away from the basin, depending whether the ocean is growing (Atlantic Type) or shrinking (Pacific Type). Therefore, the convectional currents or even the earth's rotation has got very little to do with the plate motion.

So can I say that the negative buoyancy of aging oceanic lithosphere provides the potential energy that powers plate tectonics??????

Simple scaling analysis reveals that the largest force acting in a typical plate tectonic cycle (spreading ridge to subduction) is the slab pull due to the negative buoyancy of the cold oceanic lithosphere, along with the dense eclogite of oceanic crust being subducted. However, one should also consider the heat budget of the mantle. If the mantle heat is mainly sustained by internal heating, then downwellings, i.e. subducting slabs, will drive convection. If there is a considerable component of bottom heating by a superheated core, then thermal upwelling would add an important driving mechanism to the mantle-lithosphere convection system as well. I think the true situation is found somewhere in between, with subduction zones certainly playing a big role.

Hi, Chandan!

There is many information about Plate tectonic motion in the J.A. Tarduno articles.

May Be !!

The main mechanisms are slab-pull and ridge-push which are tightly joined to the convection cell schemes, at least in 2D. Then, there are other influences, minor, but important as deep mantle circulation, plumes, drippings etc.

Unfortunately, till the present the absolutely reliable reasons of plate movement are not revealed. Apparently, there are several factors in different degree influencing to the process of movement: density and viscosity redistributions in the Earth's crust, changing some deep boundaries in the crust, downward suction, changing the Earth angle velocity rotation, the tidal effects from the Sun and Moon (the last effects are gravitationally small, but disturb all the Earth as a whole), etc.. I propose that 4D modeling of these processes at supercomputers is the task for a new generation of geophysicists.

Some researchers suggest there are also other contributions to plates motions.

You can find some of these in the following papers:

Riguzzi F., Panza G., Varga P. & Doglioni C. (2009): Can Earth's rotation and tidal despinning drive plate tectonics? Tectonophysics, doi:10.1016/j.tecto.2009.06.012.

Doglioni C., Tonarini S. and Innocenti F., (2009), Mantle wedge asymmetries and geochemical signatures along W- and E-NE-directed subduction zones. Lithos, doi:10.1016/j.lithos.2009.01.012

I am not a specialist in the plate tectonic motion, but these articles, recently published by spanish researchers of the ICMAT, show a new model, interesting and probably controversial:

J. Curbelo, A. M. Mancho. Spectral numerical schemes for time-dependent convection with viscosity dependent on temperature. Communications in Nonlinear Science and Numerical Simulation, 19 (2014) 3, 538-553. (http://www.sciencedirect.com/science/article/pii/S1007570413001494)

J. Curbelo , A. M. Mancho. Bifurcations and dynamics of a convection problem with temperature-dependent viscosity under the presence of the O(2) symmetry. Physical Review E 88, 043005 (2013). (http://pre.aps.org/pdf/PRE/v88/i4/e043005)

J. Curbelo , A. M. Mancho. Symmetry and plate-like convection in fluids with temperature-dependent viscosity. Physics of Fluids 26, 016602,(2014) (http://scitation.aip.org/content/aip/journal/pof2/26/1/10.1063/1.4850296)

The subduction of continental plate is either pulled by the subduction of oceanic plate or pushed by the other plate. While the gravitational sinking of oceanic plate is a key to subduction into trench, upwelling of the asthenospheric mantle drives seafloor spreading for movemeng of the oceanic plate.

Dear colleagues, according to the results of our measurement of deformation of rock mass, temperature variations and seismicity, we postulated the hypothesis of extraterrestrial sources of motion of lithosphere plates. The main portion of the movement (energy accumulation) is excited by solar irradiance and by the generation of thermoelastic waves. The lesser influence have changes of the Earth´s rotation (LOD variations), tides and direct gravity influence of Monn and planets due to inertial motion of the Earth like SIM in the case of Sun (Charvatova 2014 : http://www.pattern-recogn-phys.net/2/issue1.html).

This hypothesis was published in the book:

https://www.researchgate.net/publication/258997698_Tilts_global_tectonics_and_earthquake_prediction?ev=prf_pub

https://www.researchgate.net/publication/259829056_Tilts_Global_Tectonics_and_Earthquake_Prediction_comment?ev=prf_pub

or in the conference proceedings and poster (EGU 2013):

https://www.researchgate.net/publication/258989334_Thermoelastic_waves_and_ratcheting__basic_mechanism_of_global_tectonics?ev=prf_pub

Only 4% of solar energy (accumulated in the crust) is enough to explain the energy budget of all of earthquake and volcano eruptions.

We were looking for such mechanism for more than 10 years and we didn´t find anything better in such complexity.

Book Tilts, global tectonics and earthquake prediction

Data Tilts Global Tectonics and Earthquake Prediction comment

Data Thermoelastic waves and ratcheting – basic mechanism of glob...

Relate buoyancy with the formation of mountain ranges such as Himalaya or Andes or Kamchatka.......relate great journey of India plate till its collision with Eurasia. Relate it with continuous seafloor spreading (that require continuous heat supply....) and many such processes that have been linked with plate tectonics, you may reach to some logical conclusion as whether negative buoyancy can be sole reason for the plate motion!!!

DRIVING FORCES FOR PLATE MOTIONS

How Mantle convection relates directly and indirectly to the motion of the Plates is a matter of ongoing study and discussion in geodynamics. Even without considering the actual mechanism of Convection, it is appreciated that there must be some way of transferring the internally derived energy to the Lithosphere in order to move the Lithospheric Plates. Different forces that presumably set the Plate motion are:

(i) Large scale Convection Current transmitted through the Asthenosphere set Lithospheric Plates motion through frictional drag at the base of the Lithosphere. Besides, the local Convection Currents exert a downward frictional pull on Plates in Subduction zones.

(ii) One of the readily understood forces on Plates is that which emerges at the spreading centre. The intrusion of magma may push the Plates away from the MOR axes. Further, since the MORs are elevated above the adjacent ocean floors, potential energy may encourage gravitational gliding towards trenches. These two forces together make up the ‘ridge-push force’. Gravity also acts in pulling a slab down and producing a Trench through ‘suction’.

(iii) The Subduction of colder and denser slab through the surrounding hotter (and because of that less dense) Mantle materials creates a positive mass anomaly or negative buoyancy, which is accentuated by intra-Plate phase transitions. A ‘slab-pull-force’ ensues tending to pull the slab downwards into Mantle. With attaining the thermal equilibrium with surrounding Mantle as the slab dips further down, it loses its negative buoyancy and experiences a ‘slab resistance force’ as it tries to penetrate further into stiffer Mantle.

In summary, the driving forces on Plates are ‘frictional drag’, ‘slab pull’, ‘ridge push’ and ‘trench pull’. It must be remembered that the subject of over-all driving force for Plate motion and its energy is still a hotly debated subject of ongoing research.

An alternative point is that a major factor of plate movementscould be the processes at the core-mantle boundary triggered by accumulaiton of slab graveyards there, so-called plume tectonics, superplumes (Maruyama et al., 2007, Gondwana Research).

I agree with Anna Safonova, the core role as a geodynamic engine is underestimated. There is indication that the core is still degassing, probably the occurrence of major episodes of interaction between the core / lower mantle are able to enter chemical plumes in the lower mantle which a potential cause of activation of asthenospheric and lithospheric events.

In my view and in accordance with many arguments in previous answers, as a consequence of gravity and density Distribution primary forces driving plate tectonics are slab pull (and locally ridge push) and forces resulting from ascending mantle material (plumes of all sorts). These forces are complemented by a number of smaller but locally significant effects, some of what have been mentioned in previous answers. The main point I would like to contribute to discussion, however, is the importance and fact that the two main forces -slab pull and mantle plumes- are both parts of mantle convection system that is inherently NON-CIRCULAR and ASYMMETRIC: The begin and end points of the concise flow segments (MOR and 670km discontinuity or CMB for the oceanic plate, see attached figure) are only connected by diverse very limited range flow pattern to conserve mass of fluid (mantle).

Slab pull and ridge push are two major forces for plate motion. The upwelling of mantle plumes can be regarded as a kind of the ridge push in discontinous spots from different depths, with different forms of ascending impact on different position of a plate.

During long-term it is primarily the second - negative buoyancy of oceanic lithosphere with respect to asthenosphere, complemented locally and regionally by mantle currents. Superplume currencts, however, for relatively short period of times may disrupt this pattern and open up large sections of new MOR-to-be and thus setting in motion a series of new Wilson cicles.

One of the possible reasons for the motion of tectonic plates from east to

west could be related to an applied torque from the Sun's Magnetic field

acting upon the Earth's Iron Core applying a force to toward the East

such that the core has one additional rotation inside the earth every

400 years. From the Core Mantle Boundary upward the layers in the mantle

creep westward over one another such that the layers farthest from the

core have the greatest cumulative westward creep. The cumulative

creep looks like a curved set of fan blades. The creep can be seen

on the cover of the March 2000 Issue of Scientific American Magazine,

and looks like the propeller of an American Nuclear Submarine, or

the Propellers on a NASA research aircraft of several years ago.

It is essentially Scimitar shaped, or crescent moon shaped.

The mass of the individual Continents most likely determines the rate

of westward creep where lighter continents are less resistant to the

applied westward forces, and move a little faster westward than the

larger Eurasian and African Continents. The Applied torque also

spins Antarctica in the counterclockwise direction, to the westward

if looking down on the continent. The applied torque is about the same

on all the continents , but the resistance to motion is not the same

for each continent.

This applies to westward movement but can not account for Northward

movement of continents that collects the continents in the Northern

Hemisphere ( for Earth), and the Southern Hemisphere ( for Mars ).

Planets undergo both energy and mass redistribution internally, and

the Earth is slightly pear shaped which drives continents from the

" higher gravitational energy location" of the Southern hemisphere

toward the " lower gravitational energy location " of the Northern

hemisphere.

The North American Continent is moving about 2 inches north, and

about 2 inches west every 25 years, more or less.

Motion is the result of applied forces in combination with the resistance

to motion, the apparent differential motion, the actual motion in

comparison to some arbitrarily assigned point as a reference,

like the Hot Spot under Hawaii.

The westward creep is quite slow in comparison to the added

extra core rotation every 400 years.

How the Earth got its tectonic plates!!

By Monte Morin

April 6, 2014, 12:00 p.m.

If you've ever felt the earth shudder beneath your feet during an earthquake, you're no stranger to the effects of Earth's ever-roaming tectonic plates.

While scientists have linked the movements of these rigid, puzzle-piece slabs to our planet's most violent events -- quakes, tsunamis, volcanic eruptions -- they have struggled to explain exactly how they came to exist in the first place.

Now, in the journal Nature, two geophysicists have proposed that Earth's outermost layer, or lithosphere, was microscopically weakened and brittled by movement in viscous layers below it billions of years ago.

Study authors David Bercovici of Yale University and Yanick Ricard of the Univeristy of Lyon note that Earth is the only planet in the solar system that appears to have tectonic plates that move freely on its surface, propelled by the motion of layers below.

"The emergence of plate tectonics is arguably Earth's defining moment," they write. "How our planet, alone amongst known terrestrial bodies, evolved the unique plate-tectonic form of mantle convection remains enigmatic."

The authors have created a mathematical model for the breaking of the lithosphere into pieces, and it involves the lava-lamp-like convection of Earth's molten mantle.

The authors argue that when cooling sections of mantle moved downward, they stretched the rocks in the overlying lithosphere and this deformation caused microscopic changes in their the crystalline structure.

From there, a "self-weakening feedback" occurred that made these deformed areas into weakened zones. These weakened areas became enlarged as the downwelling movement of the mantle shifted to other areas, they argue.

"Although this case is highly idealized, it shows that a fully developed plate can evolve from a downwelling only," they wrote.

The process likely began about 4 billion years ago, and caused complete fractures 3 billion years ago, the authors write.

The authors also offer an explanation as to why at least one other planet, Venus, lacks similar plates.

Due to far hotter temperatures, any damage caused to the surface would become healed over time, according to their model.

"Only very faint weak zones accumulate because damage itself is weaker while healing is stronger," the authors wrote.

http://www.latimes.com/science/sciencenow/la-sci-sn-how-the-earth-got-its-plates-20140404,0,2472994.story

Steady rotation of the Earth provides a long-lived convection cells in the mantle material. They, in turn, create the conditions for sustained stable plate motion (convection currents) - part of the Earth's crust floating in the direction of the top of the convective flow. The lifetime of such convection cells is controversial. The reason for their change is not clear until the end. Plumes? Maybe. The cause of the plumes also not clear.

Perhaps an increased rate of radioactive decay would provide the heat energy to drive plate tectonic motion?

The question of what drives the plates remains controversial to this day, but now many geoscientists accepted a convection- cell model, which stated that convection - driven flow in the mantle drives the plates. In this model, plates where carried along on the back of flowing asthenosphere, which was thought to circulatein simple elliptical paths; upwelling of hot asthenosphere presumably occurred at mid- ocean ridges, while downwelling occurred at the margins of oceans or at subduction zones. In this model , the flowing asthenosphere exerts basal drag, a shear stress , on the base of the plate, which is sufficient to move the plate. This image of plate motion , however, was eventually discarded for, while it is clear that the mantle does convect, it is impossible to devise a global geometry of convection cells that can explain the observed geometry of plate boundaries that now exist on earth.

Subsequent calculations showed that two other forces , ridge- push and slab-pull play a major role in driving plates.........

One of the major outcomes of Chandrayaan is that Moon is not dead but is tectonically active......Moon has no plates(??), separated from the Earth millions of years ago (probably same activity is still going on in Moon that made Earth active at the time of Moon's separation).......It was bombarded by stray cosmic bodies (but so was Earth). What makes Moon active is now a million dollar question. Should we expect an unambiguous evidence in support of prevailing theory.................or a paradigm shift?????

The Moon may have a major input into why the Earth has larger more

developed plates and plate movements than the smaller planets like

Venus, Mars, Mercury, and the Moon.

The combination of force vectors from the Sun, and the Moon are ever changing

in direction and also in magnitude, so the resulting internal motions of

materials inside the Earth are likely to be of greater magnitude.

The Earth is thus always in the process of undergoing Geo-Dynamic-equilibrium.

Rather than a Geo-static- equilibrium.

There is a problem with the basic concept of convection cells in a medium

in which the materials are not of uniform density. if the density of the materials

is stratified, then, it can not undergo convection cell mixing. this would mean that

material would need to move laterally through shearing processes, and would look like tank treads all stacked up, and all moving westward on atop another.

This can be seen on the cover of the March 2000 issue of SCIENTIFIC AMERICAN

MAGAZINE.

If there is anything that the History of Science teaches us, it is that our understanding of geophysics is ALWAYS rudimentary. And present theoretical possibilities promise more of the same going forward.

Arguably, the most fundamental question in the Theory of Plate Tectonics is: What drives the lateral motions of plates?

A current constraint in planetary physics is not so much rightfully considering Earth’s geodynamics as an open system, including its astronomical context, but in the difficulty of imagining quantitative methods by which to measure geodynamic effects. The RG preprint linked below provides quantitative methods and spectral evidence that should move geodynamics closer to a solution to this long-standing conundrum of what drives plate motions. The second link provides mean-pole data from the IERS website that may be used to replicate this intriguing result. After calculating mean-pole acceleration, the spectral analysis should take your statistics practitioner less than two hours. Are you ready for a surprise? Please share your thoughts and results, if you try it.

https://www.researchgate.net/publication/322666165_Spectral_spatial-statistical_and_graphical_evidence_that_gravitational_interaction_with_the_Moon_assists_in_driving_Earth's_tectonic_plates-Part_1

http://hpiers.obspm.fr/iers/eop/eopc01/mean-pole.tab

The Earth derived the Plates from the Change in the rate of growth and expansion

that occurred following the Major Impact that occurred at Wilkes Land Antarctica.

The impact occurred at 252.17 Ma, but it took until 180 Ma for the Earth to heat up enough to grow and expand enough to fracture the surface and seperate into several different Continental Plates from what had previously been one contiguous continental surface (pangaea). The Impact in Antarctica was assuciated with an antipodal Energy focal point called the Siberian Traps. The antipodal rupture leaked enough lava to cover the entire surface of the Earth to a depth of 10 feet. The actual localized depth was about two miles of lava flows.

I suspect the Impactor was made of Uranium, and it detonated upon impact, the result was 28 large chunks of Uranium that scattered over the Earth, and burned their way down into the mantle, and down to the Earth's core. The result was 28 hot spots, One 480 km Impact Crater, the Siberian Traps, and a large amount of Uranium dust that ended up in layers in Basins worldwide. One of those Basins was at Crown Point NewMexico, and was going to be mined, until the price of Uranium fell from $45.00 to $ 16,00 , and it became uneconomical to mine deep deposits of Uranium.

Between Now and 180 Ma, the Radius of the Earth can be approximated by taking the Base = 0.996 558 283 and raise it to the " N " Ma, to get the 0.xxx xxx xxx Radius at the time period. For example: at 66.043 Ma, the radius was 0.996 558 283 ^ 66.043 = Radius = 0.796 368 413 R or 5074.8232 Km Radius. And

( 5074.8232 / 6372.4567 ) X 180 degrees = 143.346 3144 degrees. This is the

arc Distance up and over the top of the Earth between the Chicxulub Impact Site, and the Deccan Traps Antipodal Energy Focal Point. The 2 Delta = 180 - 143.346 3144 = 36.653 68555 degrees. The one Delta = 18.326 84278 degrees.

Chicxulub Impact site is now 20.4 degrees Noth of the Equator. At the time of Impact, It was 20.4 - 18.326 84278 = 2.073 16 degrees Noth of the Equator, and Western India which was 180 degrees away, was 2.073 16 degrees south of the Equator. Since Both Locations have moved North of the Equator, the conclusion is that the Earth grew in size (or expanded), and Most of the Continents have moved Northward with millions of Years of elapsed time, and they have moved apart, like the doors of a Delorean as they open upward.

Only use 0.996 558 283^"N" Ma between 180.0 Ma, and Now to determine the Radius.

I just ran into a tool that Models Plate Movement.

Look Up UNAVCO Plate Motion Calculator in Boulder Colorado.

There are several Models for Plate Motion for different Plates, with or without

Plate Rotation. It actually makes sense that Plates move, and they rotate when either North or South of the Equator. If they were perfectly centered over the Equator, they should move westward without rotation. Plates over the poles or part way between the poles and the Equator should rotate as their distance between the polar axis of rotation is not a constant.