Abstract

This treatise offers an alternative analysis based on the forces associated with the rotational velocity of the Earth to explain supercontinent break-up followed by tectonic plate movements, subduction, and orogenic processes. This is in contradiction to current wisdom which accepts that the movement of a continental plate (CP) is the result of the ‘pulling action’ applied to it by the subduction of the higher density oceanic lithosphere (OL) as it descends below the CP. The direction of the heated convection currents considered to cause subduction must vary over time and distance. It was this inability to reconcile the long term (Mya’s) unidirectional movements of tectonic plates in an omnidirectional convection current based force environment, that prompted the author (Maurer 2002 to 2020) to analyse the constant forces generated by the rotational velocity of the Earth.

Furthermore, the innovative introduction of circumferential tensile forces and momentum to the study of plate tectonics allows for the reconsideration and possible separation of the role of subduction from the force driving tectonic processes. To date, the magnitude of the circumferential forces, often incorrectly termed ‘inertial forces’ have been generally considered to be negligible in the context of tectonic movements. It will be demonstrated that a small (1.0 km) offset of the centre of mass (COM) from the centre of rotation will create circumferential stress forces at the Earth’s outer rim that are sufficient to break up a supercontinent. This approach thus allowed the development of the equation F = MRω²Eπ/4 relating the circumferential tensile forces (F) to the offset (E) centre of mass (taken as 1.0 km) from the centre of rotation and the rotational velocity (ω) of the Earth. The circumferential forces developed within the lithosphere due to the permanently rotating ‘unbalanced’ or ‘wobbly’ planet are considered primarily responsible for the perpetual movement of the tectonic plates. It is this continuous action that allows for an alternative cycle of lithosphere regeneration to the Wilson cycle to be proposed and illustrated. The break-up of Pangea in the early Jurassic period c.200Mya is used as an example throughout this treatise.

The further introduction of Momentum (Mass x Acceleration) to the motion of a continental plate has resulted in a complete rethink of the cause and role of subduction in tectonic plate movements. This analysis thus postulates that the moving continental plates (CP) as they break away from a ‘halted’ supercontinent start to accelerate from zero velocity (Vo) to plate velocity (Vp). The developed Momentum (p) = Mass of CP x Velocity of CP = Mcp x Vp will continue to keep the CP moving until collision at a convergent margin. The downward force due to the massive weight of the lower density CP will push down the oceanic lithosphere over which it is moving, against the upward buoyancy and the viscous drag forces. It is this action that initiates the subduction cycle and slab pull process. Slab break away into the mantle with the loss of the slab pull force has not been observed to stop, or impede the continuous movement of the CP. It is thus possible to illustrate that subduction is a direct consequence of tectonic movements as distinct from being the cause. By implication, it is considered that the complex circulatory system of heated convection currents within the mantle has a passive rather than an active role in tectonic plate movements. The application of momentum to the movement of the Indian Plate allows for an alternative approach to be taken to account for the varying velocity changes noted in its north-east movement from its split from Madagascar to the formation of the Himalayan Mountain range in Eurasia.

The analysis given in this paper further shows that the Earth alongside the other planets require an ‘offset centre of mass’ to allow the mutual gravitational pull between the Sun and the planets to establish an N-S axis around which the planets are caused to rotate. This, in turn, gives rise to a rational explanation of the reason for the rotation of planets (except Venus unless considered as being upside down) in the same anti-clockwise direction as the Sun itself. This is in keeping with Kepler’s Laws of orbital motion in which the Sun rotates the planets.