Jornal de Geologia e Geofísica
Acesso livre

Abstrato

Continental Drift and Plate Tectonics vis-a-vis Earth’s Expansion: Probing the Missing Links for Understanding the Total Earth System

Sen S*

Hypotheses like continental drift, plate tectonics or Earth’s expansion should not be considered as viable in view of solid and rigid state of mantle which, in contrast, would resist such phenomena. Based on Hilgenberg’s model of Earth’s expansion (1933), the author elucidates that before expansion when the Earth was small and devoid of oceans, its mantle must have been sufficiently fluid owing to association of ocean-forming water. Further, matching thickness of fluid outer core and extent of radial expansion of the Earth strongly support that the outer core was opened up as a void geosphere owing to planetary expansion. At the deep interior of the planet, owing to occurrence of a void or pseudo-fluid geosphere separating basaltic mantle and solid iron core, an additional force of reverse gravity would develop acting in opposite direction of normal inwardly directed force of gravity. This postulation leads us to consider that in the deep interior of the planet an upwardly directed force of gravitational attraction would act in a predominant manner, thereby sustaining sufficiently low temperature and pressure condition and magnetic nature of the inner core which completely agrees with observed features of terrestrial magnetism. Over the Earth’s surface the crustal layer was fragmented due to expansion while through the expansion cracks widespread incidences of magma emission occurred forming rudimentary ocean basins. With further expansion, these basins were expanded and filled up with water that degassed from the mantle associated with the process of magma emission while owing to desiccation, the mantle itself eventually turned into a rigid body. Before expansion of the planet when the iron core and the mantle were juxtaposed to each other, due to external magnetic influence the magnetic iron core was deflected causing major change in polar and equatorial disposition of the planet. Subsequently in younger geological period when due to expansion a major void geosphere was opened up between the iron core and mantle, external magnetic influences caused the magnetic core to execute smooth revolutions giving rise to new magnetic phenomena like pole reversal and polar wandering, documented over the planet’s younger strata. It may be noted that while due to expansion, the continental fragments would tend to move away from one another, owing to rotation of the planet along its axis of rotation some continental fragments came closer to each other or even collided to form mountain ranges.