Greinar (Vísindafélag Íslendinga) - 01.01.1977, Blaðsíða 134

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rise. But the local conditions must decide, whether this ex-
planation suffices.
In the case of the ocean floor, uplift due to coverage with a
thickening layer of organic deposits is of special importance.
Coverages of continental areas by such deposits do certainly
also take place. Because of the depth of the Moho here, the
temperature effect on the sinking of the Moho would, first, lag
much behind the deposition, and second, the effect may be
very small, as the heat flow in continental areas is generally
thought to come from sources within the respective crust.
Similarly, the continental crust is mostly so strong that
the effect of the stress fields of Chapter 3 are also somewhat
in doubt from the theoretical side. But here, clear geological
evidence tells us by uplifts of large parts of continents and
also subsidences, that also here the Moho must indeed fluc-
tuate up and down in geological times. By thorough know-
ledge of the geological history of certain areas, the verification
of the nanocrystalline state should provide an understanding
of phases of uplifts and subsidences, by due consideration
of the time phase lag that must be expected, as pointed out
above.
From a theoretical point of view, the most satisfactory
thing about the nanocrystals is that they provide a way for
the exogenous forces to work inside the upper parts of the
earth and thus enable us to dismiss from geoscience the so-
called endogeneous forces, which could not possibly be more
than one ten millionth of the exogeneous forces, driven by
solar energy.
In this as in the eases stated earlier, the introduction of nano-
crystals into geoscientific considerations is a challenge to ex-
perimentalists to give corresponding experiments an important
geoscientific aim.