The future of plate tectonics

A public lecture for the Geological Society by Phil Heron (October 2018).

Plate tectonics has been within the mainstream thinking of geoscience for over 50 years. The theory describes the large-scale motion of the Earth’s outer layer to explain tectonic activity like earthquakes and mountain ranges at the edges of our continental landmasses (for instance, the San Andreas Fault in California and the Andes in South America).

Technological improvements as a result of World War II allowed for a better understanding of our planet - seafloor mapping uncovered tectonic plates being made at mid-ocean ridges (e.g., the mid-Atlantic) and being destroyed at their margins where they underthrust the continents (e.g., the Andes). Plate tectonics is indeed one of the greatest discoveries of the 20th century, with the movement of the continents and recycling of the oceans playing a significant role in shaping the climate and ecology on our habitable planet.

Over 50 years on, scientific discoveries have not stopped - we have been able to illuminate deeper into our planet and develop a complex, interconnected system of a dynamic Earth where the impact of plate tectonics is far reaching.

In this talk, we will be taking a geological journey from the crust to the core. Through analyzing current research (including computational numerical modelling), I’ll highlight some theories regarding how our planet’s moving surface influences (and can be influenced by) the evolving landscape deep beneath our feet.

An example of which is modern geophysical imaging showing ‘blobs’ at the boundary of Earth’s core and mantle, more than 2,800 km below the Earth’s surface. These hot, possibly dense, piles of material are thought to be continental in size and over 100 times higher than Mount Everest. Many theories exist on their origin and behaviour, but current thinking is that tectonic plates (in the form of oceanic seafloor destroyed at continental margins) may interact with these blobs in the deep Earth to generate extinction-inducing super-volcanoes (called large igneous provinces). The role of such blobs in how our planet’s climate and ecology evolves is currently being hotly debated.

The talk will discuss the future of plate tectonics in two senses: how do new discoveries fit within the theory of plate tectonics, and how will motion on our surface evolve over time? By delving into the deep of our interior, we may be able to discover the secrets of our past - and therefore what the future could hold for our dynamic Earth.