Dear Mario,

please use this book, it's may helpful for you.

Dear Mario, the various theories you mentioned are all parts of the main mechanism consisting in the behavior of the asthenospheric portion of the mantle. Have a look to the this article whose large bibliography may be useful for your reaserch

Dear Mario,

As you might have known, in science anyone can always generate explanations to certain natural phenomena so long as the model can answer the usual scientific questions. Having said that, I wish to point out that all the mechanisms are all correct. However, to me, the simplest explanation is the geodynamic collision model. Whenever mobile blocks (plates) collide, the less dense blocks, again density of the blocks depends on many factors including temperature and saturation level, will always float above the denser one that will be subducted. A good example is the subduction of more dense oceanic Indian plate under the continental Eurasian plate. All associated diagrams for this model are very clear to understand.

Subduction zones, created by geological processes, are sites of convective accumulation and sinking of higher density materials of the Earth’s lithosspheric plates beneath the lower ones at the convergent plate boundaries where one plate of oceanic lithosphere converges with another plate. Although its origin has a dynamic discussion and its studies are continuous, spontaneous subduction zones occur when denser oceanic lithosphere is able to sink beneath adjacent oceanic or continental lithosphere due to density variations. Again, induced subduction zones occur when the existing mobile plates initiate a new subduction zones by forcing oceanic lithosphere to rupture and sink into the asthenosphere (a weak part of the earth’s upper mantle where rock s can be deformed in response to stress, resulting in a motion of the overlying crust). Spontaneous and induced subduction zones, in a way can eventually result in self-sustaining subduction zones, when the oceanic crust changes at deeper depth and becomes denser than the surrounding mantle rocks. Often times, results from numerical models always favour induced subduction initiation for most modern subduction zones, and this is in support by geologic studies.

Dear Mario, Before determining the origin of any phenomenon, it is good to understand what kind of phenomenon it is. In the case of subduction, everything is complicated due to the fact that it has been tied for a very long time to the unconfirmed idea of ​​the infinite sinking of the oceanic crust, which constantly draws down the descending movement of the mantle convective cell. If we look at "subduction" soberly, we can say that it is most likely a zone of interaction between oceanic and continental slabs with predominant compression, an analog of a collision, or obduction, but with a predominant under-thrust component. Now in the zones of "subduction" compression and underlay predominate, later in the framework of the oscillatory process they can be replaced by stretching and spreading. Infinite podviganie plates on the outer part of the descending convection cell is unlikely by the elementary laws of physics. The geometric impossibility of this is proved among other authors and by me. Below is a reference of my abstracts on EGU-13 and mu presentation on EGU-14 on this topic.

Geophysical Research Abstracts

Vol. 15, EGU2013-6448, 2013

EGU General Assembly 2013

© Author(s) 2013. CC Attribution 3.0 License.

the begining of another fastter accretion in another area due to astenospheric dynamic and plate tectonic.

Hello Mario, science as you know has borders and knowledge continues to expand those limits. As mentioned Livio all parts of the main mechanism.

Check this:

https://epdf.tips/arc-continent-collision-frontiers-in-earth-sciences.html

Thank you very much for all colleagues for your suggestions and ideas. My best wishes. Mario

Dear Mario:

Subduction zones, is a reponse of astenospheric convection and , are sites convergent plate boundaries where higher density and colder materials of oceanic lithospheric plates plunge beneath the another oceanic or continental lithospheric plate. The begining of a faster spreading movement in another area could be at the origin of the subduction.

It must be gravity contrast (density) between colliding masses and how compact each mass is.

I recommend Davit's answer

Hi Mario,

See some of these key references on subduction initiation for more information:

Hall, R., 2018. The subduction initiation stage of the Wilson cycle. Geological Society, London, Special Publications, 470, pp.SP470-3.

Ishizuka, O., Tani, K., Reagan, M.K., Kanayama, K., Umino, S., Harigane, Y., Sakamoto, I., Miyajima, Y., Yuasa, M. and Dunkley, D.J., 2011. The timescales of subduction initiation and subsequent evolution of an oceanic island arc. Earth and Planetary Science Letters, 306(3), pp.229-240.

Peng, H. and Leng, W., 2017. Progress in the study of subduction initiation. Journal of University of Science and Technology of China, 47(2), pp.163-175.

Stern, R.J., 2004. Subduction initiation: spontaneous and induced. Earth and Planetary Science Letters, 226(3-4), pp.275-292.

Here is an answer not based on prevailing "official" geologic doctrine but on a pot of water on a stove, The water is heated from below as is the mantle of the Earth. The heated water expands and its density decreases so that it gains buoyancy relative to its surroundings and rises like a balloon (actually like a bubble), So the base of the mantle is heated and also wishes to rise like a balloon. But the overlyinng cooler upper mantle and crust resists. So the lower mantle becomes hotter and more fluid and exerts pressure upward through a region of the mantle where the lateral confining pressure is isotropic so that the vertical rise is not shunted to the side, Hot lower mantle or its thermal pulse eats its way upward to break through overlying floating light-weight continental crust that like the froth atop boiling fudge is pushed aside as a rift. Now the upwelling mantle (that, by the way, undergoes all manner of chemical change and mixing on its upward journey) on enountering the overlying fluid ocean has nowhere to go but to spread laterally and cool until it runs headlong into another spreading center. At that point push comes to shove; something has to give and since the rock is too heavy to go up it goes down as the loser in the battle of clashing plates. Thus you have mid-oceanic rises, seafloor spreading and downward directed subduction zones.

Is this a profound revelation? Absolutely not!

Is it simplified? Yes!

Is it overly simplified? To a degree, yes!

Are details missing? Of course!

Is it wrong? Well, I leave that to you and your wisdom, but, as for me, I bid you adieu.

I agree with response of V. M. Anokhin , Wafik Amina, Jorge Costa-de-Moura and Dwight Hoxie . Their answers are enough.

We do not need a revelation.... but the answers are a revelation itself !!!!!! A lot of information, bibliography, references, ideas ...

Thank you again!!!!!!

Dear All:

I am correcting my new ready argumentative article with arguments against to subduction process process I would like to ask you: if the next sentence information is correct or not:

The phenomena of subduction was formulated first by Isacks, B.L., Oliver, J. and Sykes, L.R., and accepted onto base of their work [Bibliography: Isacks, B.L., Oliver, J. and Sykes, L.R., 1968, Seismology and the new global tectonics, J. Geophys. Res. 73: 5855–5899] Based on the location of the hypocentres of earthquakes to the west of the KT (Kermadec-Tonga) trench.

Every better and honestly correction is welcome (author, the first article, and time)

This small help is welcome from the supporter of PT, too. (I would like to get response in few days)

Regards,

Laszlo

Science has four characteristics:

1. Science does not start with preconceptions / opinions without a base.

2. Science starts with evidence and scientists build theories based on this.

3. Evidence is obtained from observation and/or experimentation. This evidence is treated as fact.

4. Theories are proved/disproved according to whether they correspond to the facts or not.

The scientific enterprise seeks to study the inner workings of nature; but that enterprise defines itself according to principles that lie outside of the parameters of its study.

This almost incredible delay in natural evolution of ideas about Geodynamics and Plate Tectonics an excellent lesson about how dangerous it is to censor out a bottle neck ideas.

My best wishes, Mario E. Sigismondi