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Numerous geological and geophysical data proved the presence of oceanic crust relicts of Tethys in the territory of Lesser Caucasus. On the basis of rocks properties, obtained at high pressures and temperatures , and numerous geological-geophysical factual data, concerning of oceanic crust Geostructurs, are presented the possible mechanism of their formations and relation between submarine landslides and tsunamis.
Analyzing the data about composition and properties of oceanic crust, we suspect that during the formation of Mid ridges, the main role belongs to serpentinized rocks of the 3-rd oceanic layer. Owing to high plasticity and low density, the serpentinized masses, by tectonic faults, in the central zone of Mid ridges, from both parties, float up and by means of protrusions implanted in the oceanic crust, then the serpentinized masses are grasp by basalts lavas. Accumulation in the axial zone of Mid ridges large masses of basalts and serpentinits, under influence of gravitation forces make slides to downwards to the foot of ridge. In the proposed model we attempted to interpret the above mentioned phenomena in the following sense:
1. Because of serpentinization of ultrabasits of upper mantle, the horizontal stress growth is more than 40- 50%. Spreading of oceanic floor can be partially conditioned by these forces. At impossibility to distensible in the lateral direction, the serpentinized masses increase vertically, both in the axial part of the ridge and in transform faults. Serpentinized blocks of the 3-rd layer from the axial part of ridge, are involved in basalt lava and under gravitation forces slide downwards. 2. On formation transform faults a definite role is played the processes of basalt masse slides, which naturally takes place permanently, owing to which one between blocks the faults are reshaped. In the transform faults the serpentinized protrusions and hydrotherms are also dated.
3. The chemical composition of basalts of Island arcs and Mid ridges basically coincide, which give us the basis to suppose that they are source commune. We suppose that in definite depth of subdaction zone there exist connection with astenosphere. In the upper mantle molten substrate is enriched by rare elements and erupted in the rift zones of Mid ridges.
4. Marginal seas extension speed is 5-7cm/year. Esteeming the proposed model, it is possible to mark that spreading of Marginal seas take place owing to eruption of magmatic masses as directly from in the region of Island arcs, as well as from astenosphere in the Mid oceanic ridges.
5. The studies of catastrophic tsunami origin in 2004 has resulted in judgment, that the formation of 30-m waves took place because also sliding process in the bottom of ocean. The volume of sliding structures, between transform faults can reach several million of km3. The sliding masses at the bottom of the ocean should invoke a movement of oceanic water and provoke the waves on the surface of the ocean.
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