An international team of geoscientists has created the first continuous full-plate model with evolving plate boundaries spanning one billion year ago to the present-day.
Plate tectonics is a unifying theory of modern geology, explicitly connecting the evolution and processes that bridge Earth’s mantle, lithosphere, hydrosphere and atmosphere.
Tectonic forces control the rates of uplift and erosion where continents collide or separate and modulate the flow of energy between oceans, lithosphere and mantle as continental configurations evolve.
Evolving plate tectonic configurations also determine changes in how species are distributed across different landmasses and infer the rates of chemical flows between the Earth’s surface and the deep interior.
Full-plate models published over the last decade collectively span the last billion year. However, each of these models covers different time periods or areas of the world and each model is based on different assumptions and hypotheses, and place differing emphases on subsets of the geological record.
Thus, although continental motions and plate boundary evolution have been categorized in some manner for the past billion year, there is no fully continuous model defining Earth’s tectonic history for this time.
“Our planet is unique in the way that it hosts life,” said Professor Dietmar Müller, a researcher in the School of Geosciences at the University of Sydney.
“But this is only possible because geological processes, like plate tectonics, provide a planetary life-support system.”
“For the first time a complete model of tectonics has been built, including all the boundaries,” said Dr. Michael Tetley, a researcher at the Université Lyon.
“On a human timescale, things move in centimeters per year, but as we can see from the animation, the continents have been everywhere in time.”
“A place like Antarctica that we see as a cold, icy inhospitable place today, actually was once quite a nice holiday destination at the equator.”
Distribution of Earth’s continental crust, ocean basins and plate boundaries in the plate model at present day. Tan polygons are areas of continental lithosphere in the Neoproterozoic, blue polygons are areas of present-day continental lithosphere. Abbreviations: A – Amazonia; Ant – Antarctica; AUS – Australia; BP – Borborema Province; CCT – Chinese Central Tianshan; Cu – Cuyania; CY – Chu Yili; K – Kalahari; KMT – Krygyz Middle Tianshan; KNT – Krygyz North Tianshan; KST – Krygyz South Tianshan; N-B – Nigeria-Benin; NC – North China; P – Paranapanema; ANS – Arabian Nubian Shield; Qa – Qaidam; Qi – Qilian; RDLP – Rio de la Plata; SC – South China; SM – Sahara Metacraton; T – Tarim; WAC – West African Craton. Image credit: Merdith et al., doi: 10.1016/j.earscirev.2020.103477.
“Planet Earth is incredibly dynamic, with the surface composed of plates that constantly jostle each other in a way unique among the known rocky planets,” said Dr. Sabin Zahirovic, a researcher in the School of Geosciences at the University of Sydney.
“These plates move at the speed fingernails grow, but when a billion years is condensed into 40 seconds a mesmerizing dance is revealed.”
“Oceans open and close, continents disperse and periodically recombine to form immense supercontinents.”
The team’s billion-year model will allow scientists to better understand how the interior of the Earth convects, chemically mixes and loses heat via seafloor spreading and volcanism.
It will also help researchers understand how climate has changed, how ocean currents altered and how nutrients fluxed from the deep Earth to stimulate biological evolution.
“Simply put, this complete model will help explain how our home, Planet Earth, became habitable for complex creatures. Life on Earth would not exist without plate tectonics,” Professor Müller said.
“With this new model, we are closer to understanding how this beautiful blue planet became our cradle.”
The study is published in the journal Earth-Science Reviews.
Andrew S. Merdith et al. 2021. Extending full-plate tectonic models into deep time: Linking the Neoproterozoic and the Phanerozoic. Earth-Science Reviews 214: 103477; doi: 10.1016/j.earscirev.2020.103477