Modelling Earth Science

19 Jan 2017

At ... Plate Tectonics models are getting more complicated all the time. Apparently, subduction by itself is not enough to explain how it occurs and internal heat from earth's core is being invoked to provide extra bite to the mainstream mechanism that drives the movement of the plates. There are various mid-ocean ridges identified but in this article in Science Advances (December 2016) we are told the East Pacific Rise is stable - unlike the Mid Atlantic Ridge that may have direct coupling with the deep mantle flow. One can see a certain amount of guesswork is involved, as the Mid AtlanticRidge may not couple with the mantle flow. It is hypothetical - but nice to model. If you thought it was only climate science that was blighted by modelling you would be wrong as it is happening in a lot of other disciplines too. In Plate Tectonics they move around blocks of land like chess pieces - playing draughts with sections of crust that are shifted from one side of the world to the other.

Convection is basically the flow of mantle material transporting heat, driving plate movement. Heating at the base of the mantle reduces density which allows buoyancy to kick in. This causes the heated mantle material to rise to the top of the mantle and into contact with the tectonic plates. Plate cooling at the surfaces creates negative buoyancy - which is said to explain the inactivity at the East Pacific Rise and the supposed Pacific subduction zone. Does this mean not a lot is happening at the subduction zone? The Mid Atlantic Ridge on the other hand is seismically active - and presumably has a direct contact with mantle material.

Meanwhile, another case of geology taking up the modelling process to re-write science is at ... and back to the Jurassic - the early Jurassic in fact, shortly after the Triassic/Jurassic boundary event. A lack of oxygen in the oceans, among other things, is detected in ocean cores, and the information is then modelled in order to come up with an explanation of what was going on. Catastrophism is of course ignored.