A new published study, using a combination of old models, new geophysical data and improved simulation software, reconstructs how plate tectonics changed the shape and position of the continents over the past 1.8 billion years.
Plate tectonics is a scientific theory describing the large-scale motion of fragments of the earth’s rigid outermost shell on an inner ductile layer. Driven by convection currents in the earth’s interior and plate boundaries sinking into the mantle due to gravitational pull, earth’s tectonic plates move as fast as our fingernails grow. However, since tectonic processes on earth started between 3.3 and 3.5 billion years ago, this speed was more than enough to move entire continents across the planet.
In one of the most complete models ever put together, a new study has condensed 1.8 billion years of plate tectonics into a 2-minute video clip.
The international study led by geophysicist Dr. Xianzhi Cao from Qingdao University, China, combined previously published maps, ages provided by mountain building processes, opening of tectonic basins and volcanic eruptions, with geophysical data made available in recent years.
Thanks to traces of the magnetic field preserved in iron-rich rocks, the authors reconstructed the former position of the continents, with radiometric dating of volcanic rocks, often associated with tectonic shifts, providing an exact time frame.
Knowing how the tectonic plates shifted over time allows scientists to better understand how earth works.
Volcanic eruptions and earthquakes are linked directly to how the plates move together. Friction along colliding plate boundaries accumulates energy that eventually will be set free as a devastating earthquake. Volcanoes form mostly where earth’s crust is deformed or breaking apart, allowing magma to rise to the surface.
The slow movements of the continents control sea level, marine currents and long-term climate changes. Even the evolution of life is influenced by plate tectonics. As continents break apart, land-based animals and plants become isolated and eventually evolve into new species.
A better understanding of plate tectonics also has practical applications. The distribution and accumulation of resources needed by our modern civilization, like coal, oil, gas, metals and rare-earth elements, is controlled by the formation of sedimentary basins and mountain ranges as continents break-up or collide.
The full paper “Earth’s tectonic and plate boundary evolution over 1.8 billion years” was published in the journal Geoscience Frontiers and and can be found here.
Additional material and an interview with study co-author Dr. Alan S. Collins was published online by The Conversation.
