Abstract

This page presents a new paradigm for geology. It is a different way of looking at the evolution and structure of the Earth—a different framework to explain the origin of geologic structures. Here is a rough outline:

1. The earth accreted much as other planets—and planetesimals—did. At a relatively early time it compositionally stratified. The iron-nickel core separated from the lighter silicates. A crust formed where the silicates reacted with the atmosphere and space.

2. Coincident with the compositional stratification, is a stratification of physical properties—viscosity and phase stability, among them. The crust is brittle, the mantle plastic but viscous (and stratified within itself), and the core liquid (with the inner core being solid).

3. Two principle forces act on the stratified Earth to create its tectonics and geology:

a. Lunar (and solar) tidal force.

b. Convective force to dissipate radiogenic and accretional heat—and to accommodate relative cooling at the crust.

4. The tidal force is vortical and acts to create a unidirectional solid earth wave moving from east to west. The force on the brittle crust is integrated downward to the point where lowered viscosity allows for movement, perhaps along areas of partial melting or conducive rock types. The integration of the force is such that it can cause continental-scale slabs of the crust to move across the face of the Earth. It can literally tear continents in half and expose the underlying mantle. This is continental drift and the tears are mid-ocean ridges. The exposed mantle is the ocean basins. The vortical force also affects the mantle and has notable impact on the core where in drives the magnetic dynamo.

5. The convective force is organized from the top down most notably in the form of Rayleigh-Taylor instability. (The commonly accepted bottom-up plume theory doesn’t work as there is no heat source at the core-mantle boundary to explain it—nor is it supported by observation.) Drips of material made dense by crustal cooling and phase change fall from the base of the crust or upper mantle into the mantle. Rayleigh-Taylor dripping is instigated by disturbances at the continental margins. Differences in the tidal force where plates meet cause propagation (often arc shaped) of linear belts of downward convective motion. These are known as subduction zones. Interaction of the plate motion and the downward motion shapes the morphology of the zones. The deep roots of convection block the tidal motion of surface slabs. This results in new tearing on the west side of arcs and the formation of back arc basins. Rayleigh-Taylor instabilities occur within continents as well. These are basins.

6. Top-down convective motions create depressions that are filled with basinal sediments and thrust slices. Once downward motion of a Rayleigh-Taylor drip ceases, isostatic rebound occurs. These are orogenic zones. Lines of drips and repeated drips along subduction zones and other orogenic belts result in overlapping and complex structures.

This paradigm replaces commonly accepted plume and convection cell theory of plate tectonics. That theory has been increasingly discredited by inconsistent observations on plumes and the failure of a viable driving mechanism for continental motion. The latter has moved from large convection cells, to ridge push, and now to slab pull. Convection cells and ridge push have been abandoned as infeasible and slab pull will soon be since earth materials cannot support transmission of the needed forces over the distances required. The suggested paradigm, while not yet complete, seems to answer all of the problems that have developed with current theory and offers explanations for most geologic features.