The stripping of the terrestrial crust   

Tokyo, 2009  L. Rabasco

“Conjugated action of the epirogenics events and the geological agents. (searching the balance)” To say that the epirogenics movements of the crust look for to restore the isostatic balance supposes to think that it had been left from an original stage of balance, but by contrary, these movements look for of progressive and continuous form to come near to an equal, ideal but generally never before different balance at every moment as different are the circumstances and always based on disturbances internal, or external to the planet. Fitting us to the case of the terrestrial crust, the unique accessible terrestrial layer of direct form, this distribution by densities is clear in which we know like the SIAL (aluminium silicates) and the SIMA (magnesium silicates). Starting off from a rather chaotic origin of the cortical masses, these over the years tend “to praise themselves/pour off” based on their densities, that is to say, the constituent masses will tend to a progressive approach to the isostatic balance that as the course of the time, the state of the matter and allow it to the energy, is possible to reach. We can intuit this process of continuous stripping by means of the geologic tracks. Example of this can be the paleomagnetics registries in the magnetite crystals that indicate the polar alternations or the relative displacements to us of the continental plates. Making use of the actualism we will be able to unravel a reasonable part of happening of the terrestrial crust. The work of the geologist is to a great extent a work of reconstruction. We imagine that to put together a film that we have only some separate  photograms. Each photogram of the film would give us “freezed images” some indications. If we interpreted correctly it will be able to help to reconstruct the script of an approximate form. Then it seems reasonable to admit that the geologists have a good approach to the geologic Earth history without getting to have the absolute certainty. That approach considers all the spatial-temporal aspects that the rocks can sow to us, that is to say, aspects, facies, morphologic, climatic, etc. The continuous stripping looks for the establishment of the greater possible balance according to the moment. In a free ideal model and projecting it towards the infinite, it would arrive at the distribution stratified in floors by densities. We could compare it imagining the state of an atmosphere without disturbances where the different gases would get ready in envelopes according to their molecular weights. Something similar we found in the composition of the inner Earth structure, in the differentiation of the concentric layers in the mantle and in the nucleus marked by physic-chemical properties represent by the discontinuities of Mohorovitic, Repetti, Gutemberg and Wiechert. The densities of the components increase strongly with the proximity to the centre (it means densities about 17 inside Earth core, being the density of majority  superficial  components less than 2.7). Extrapolating, the “order-disorder” is from the atomic level to cosmic a natural terrain feature of the matter, that is pronounced in its disposition and its physic-chemical balance, endogenous and exogenous.

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