New model of tectonic plates with darker shaded boundary zones. Credit: Dr. Derrick Hasterok, University of Adelaide
New models showing how continents came together provide new insights into the history of the Earth and will help to better understand natural hazards such as earthquakes and volcanoes.
“We looked at current knowledge of plate boundary zone configuration and past construction of the continental crust,” said Dr. Derrick Hasterok, a professor in the Department of Earth Sciences at Adelaide University. he led the team that produced the new models.
“The continents assembled a few pieces at once, a bit like a puzzle, but every time the puzzle was finished it was cut and rearranged to produce a new image. Our study helps to illuminate the different components so that the geologists can gather the above images.
“We found that plate boundary zones account for nearly 16 percent of the Earth’s crust and an even larger proportion, 27 percent, of the continents.”
“Our new tectonic plate model better explains the spatial distribution of 90% of earthquakes and 80% of volcanoes in the last two million years, while existing models only capture 65% of earthquakes.”
– Dr. Derrick Hasterok, Professor in the Department of Earth Sciences, University of Adelaide
New models showing the architecture of the Earth. Credit: Dr. Derrick Hasterok, University of Adelaide
The team produced three new geological models: a plate model, a province model, and an orogeny model.
“There are 26 orogenies – the process of mountain formation – that have left their mark on the current architecture of the crust. Many, but not all, of them are related to the formation of supercontinents, ”said Dr. Hasterok.
“Our work allows us to update maps of tectonic plates and continent formation found in classroom textbooks. These plate models, which have been assembled from topographic models and global seismicity, have not been updated since 2003. “
The new plate model includes several new microplates, including the Macquarie microplate in southern Tasmania and the Capricorn microplate that separates the Indian and Australian plates.
“To further enrich the model, we added more accurate information about the boundaries of the deformation zones: previous models showed them as discrete areas rather than wide zones,” said Dr. Hasterok.
“The most significant changes in the plate model have occurred in western North America, which often has the boundary with the Pacific plate drawn as the San Andreas and Queen Charlotte faults. But the recently demarcated boundary it is much wider, about 1500 km, than the previously drawn narrow area.
“The other big change is in Central Asia. The new model now includes all the deformation zones in northern India as the plate climbs toward Eurasia.”
A story told by the continents. Credit: Dr. Derrick Hasterok, University of Adelaide
Published in the journal Earth-Science Reviews, the team’s work provides a more accurate representation of Earth’s architecture and has other important applications.
“Our new tectonic plate model better explains the spatial distribution of 90% of earthquakes and 80% of volcanoes in the last two million years, while existing models only capture 65% of earthquakes,” said Dr. . Hasterok.
“The plate model can be used to improve georisk risk models; the orogeny model helps to understand geodynamic systems and better model the evolution of the Earth, and the province model can be used to improve mineral prospecting. “
Reference: “New Maps of Global Geological Provinces and Tectonic Plates” by Derrick Hasterok, Jacqueline A. Halpin, Alan S. Collins, Martin Hand, Corné Kreemer, Matthew G. Gard and Stijn Glorie, May 31, 2022, Earth-Science Reviews. DOI: 10.1016 / j.earscirev.2022.104069
The work included researchers from the universities of Adelaide, Tasmania, Nevada-Reno and Geoscience Australia.