Hydridic Earth: the New Geology of Our Primordially Hydrogen-rich Planet by Vladimir N. Larin

Author:Vladimir N. Larin
Language: eng
Format: epub
Tags: Geology, hydrogen, hydrides, cosmochemistry
Published: 1993-03-15T00:00:00+00:00

Cfiapter VII

problem presents itself in the perfect homogeneity of the trapps mixture. This is manifest in the uniformity of trapp mineralogy and element content (such as the 87 Sr/ 8S Sr ratio). Naturally, we refer to areas that have remained free of differential rccrystallization and other influences of postmagmatic alteration.

Lastly, the geodynamic background of trapp-forming processes is characterized by an absence of discernible tectonic activity. This fact has led some authors to consider plateau basalts as examples of autonomous magmatism unrelated to tectonics.

Let us now consider a solution to the problem of trapp origin in the light of the hypothesis of the primordially hydridic Earth. The initiation of plateau basalt effusions on a massive scale coincided chronologically with the acceleration of ocean-forming processes, and, thus, must be related to Earth’s expansion. Old platforms with localized plateau basalts represent the most stable parts of continents. Beneath them, the asthenosphere is frequently absent. The most likely characteristics for deformations that occur on a rigid, loaded arc of a sphere in the course of unbending (flattening) it, is precisely predictable from case histories of the destruction of bearing structures (Figure 38). This observation makes it possible to establish in principle the nature of different.kinds of faults that occur in upper and lower horizons of the external geosphere during expansion of the planet. On the one hand, tensional strains in lower horizons will induce vertical tectonic ruptures (zones of tectonic weakness). These will penetrate upward onethird to one-half way through the silicate-oxide shell. On the other hand, as the inner surface of the shell is shorter than the outer one, a decrease in external curvature may trigger horizontally-oriented, stress-release fractures resembling desquamation in the upper levels of the shell (Figure 38).

In terms of our concept, the uneventful tectonic regimes associated with trapp formation preclude anticipating that the high levels of heat conducted from the Earth’s interior by effluent hydrogen could have provided the energy for magma generation. Had such effluence existed, it would have induced tectonic activity (Figure 18). Nevertheless, the presence of hydrogen in trapps does indi-cate the existence of some sort of flow of the gas, albeit perhaps in weak and dispersed streams.

Even a minor admixture of hydrogen in a metal brings about a dramatic change in its physical properties. As earlier shown, under conditions of high

Figure 38

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