New Understanding of Earth’s Architecture: Updated Maps of Tectonic Plates

New models that depict how the continents were put together are shedding new light on the Earth's past and will aid in a better understanding of natural disasters such as earthquakes and volcanoes.

“We looked at the current knowledge of the configuration of plate boundary zones and the past construction of the continental crust,” said Dr. Derrick Hasterok, Lecturer in the Department of Earth Sciences at the University of Adelaide, who headed the team that developed the new models.

“The continents were assembled a few pieces at a time, a bit like a jigsaw, but each time the puzzle was finished it was cut up and reorganized to produce a new picture. Our study helps illuminate the various components so geologists can piece together the previous images.”

“We found that plate boundary zones account for nearly 16 percent of the Earth’s crust and an even higher proportion, 27 percent, of continents.”

Three new geological models were created by the team: a plate model, a province model, and an orogeny model.

“There are 26 orogenies – the process of mountain formation – that have left an imprint on the present-day architecture of the crust. Many of these, but not all, are related to the formation of supercontinents,” explained Dr. Hasterok.

“Our work allows us to update maps of tectonic plates and the formation of continents that are found in classroom textbooks. These plate models which have been assembled from topographic models and global seismicity, have not been updated since 2003.”

The Macquarie microplate, located south of Tasmania, and the Capricorn microplate, which divides the Indian and Australian plates, are among the additional microplates included in the revised plate model.

“To further enrich the model, we added more accurate information about the boundaries of deformation zones: previous models showed these as discrete areas rather than wide zones,” added Dr. Hasterok.

“The biggest changes to the plate model have been in western North America, which often has the boundary with the Pacific Plate drawn as the San Andreas and Queen Charlotte Faults. But the newly delineated boundary is much wider, approximately 1500 km, than the previously drawn narrow zone."

“The other large change is in central Asia. The new model now includes all the deformation zones north of India as the plate bulldozes its way into Eurasia.”3

The team's approach, which was published in the journal Earth-Science Reviews, gives a more realistic portrayal of the Earth's architecture, among other things.

“Our new model for tectonic plates better explains the spatial distribution of 90 percent of earthquakes and 80 percent of volcanoes from the past two million years whereas existing models only capture 65 percent of earthquakes,” said Dr. Hasterok.

“The plate model can be used to improve models of risks from geohazards; the orogeny model helps understand the geodynamic systems and better model Earth’s evolution and the province model can be used to improve prospecting for minerals.”

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, 31 May 2022, Earth-Science Reviews.
DOI: 10.1016/j.earscirev.2022.104069