Using Supercomputers to Understand How Supercontinents Form and Drift Apart

MOVERS AND SHAKERS: USING SUPERCOMPUTERS TO UNDERSTAND HOW SUPERCONTINENTS FORM AND DRIFT APART PROFESSOR ZHENG-XIANG LI, OF CURTIN UNIVERSITY IN WESTERN AUSTRALIA, HAS COMBINED HIS LOVE OF TRAVEL WITH A LIFE-LONG INTEREST IN NATURE TO STUDY THE PROCESSES THAT SHAPE THE EARTH. HIS RESEARCH GROUP USE SUPERCOMPUTERS TO MODEL THE CHANGES TO OUR PLANET OVER THE PAST TWO BILLION YEARS, IN A PROCESS CALLED 4D GEODYNAMIC MODELLING Professor Zheng-Xiang Li, based at Curtin the rocks are solidified, these minerals IMAGINE THIS University’s School of Earth and Planetary become “locked in” and act like tiny magnets Sciences in Australia, has spent his career or compasses. By studying these magnetic A continent is one of Earth’s seven main trying to understand the forces that shape minerals, or needles, Li and his team are able divisions of land: Asia, Africa, North our planet. to track how continents have moved over time America, South America, Antarctica, Europe and look for patterns, which they can then and Australia. These continents sit on Li is a leader in the field of Earth dynamics (a compare to what they know about Earth’s tectonic plates that move around the planet branch of geophysics), and he and his team internal geometry today. at speeds of a few centimetres a year. Over have been working on a project that aims to millions of years, continents move towards understand how the Earth works. They are The researchers are also modelling the forces each other to form supercontinents, before doing this by studying plate tectonics – a that drive the formation and breakup of breaking up again and moving away from scientific theory that describes the surface of supercontinents. Every 500-700 million each other – again, over millions of years. the Earth as an outer shell divided into plates years, 75% or more of the Earth’s landmasses The last supercontinent, known as Pangea, is – and investigating how these tectonic plates join together to form a single mass known as believed to have formed around 320 million interact with deeper Earth over time. a supercontinent. One of the key questions years ago. that Li and his team would like to answer is WHAT EXACTLY ARE LI AND how many supercontinents have formed over The continents are surrounded by one HIS COLLEAGUES TRYING TO Earth’s history. continuous body of water, which is divided up UNDERSTAND? into four oceans: the Pacific, Atlantic, Indian Our planet formed about 4.5 billion years ago; HOW DO THEY INVESTIGATE HOW and Arctic Oceans. A superocean is defined Li’s group is focusing on the past 2 billion years. SUPERCONTINENTS FORMED as a continuous body of water surrounding a Because we cannot see directly into the deeper MILLIONS OF YEARS AGO? supercontinent. For example, according to Earth and study how things work down there, “New geophysical imaging techniques allow us worldatlas.com, the Panthalassa superocean it has been difficult for scientists to figure out to gain increasingly clear images of what the surrounded the supercontinent Pangea. how tectonic plates work. deep Earth looks like,” says Li, “and powerful supercomputers let us simulate how Earth’s How long do you think it will be before the Li’s group aims to understand how the Earth tectonic plates interact with the deeper Earth next supercontinent and superocean form? has evolved over the past 2 billion years with increasing resolution, and further back through palaeomagnetism, a branch of in time.” geophysics that studies magnetism in rocks. Indeed, cutting-edge geophysical techniques, As magma or lava cool (or when fine sediments which allow the precise dating of geological settle at the bottom of seas and lakes), tiny events and the analysis of the physical and iron-bearing minerals in the rocks or sediments chemical nature of rock samples, have enabled align with the Earth’s magnetic field. Once scientists to gather a wealth of data from 00 Find this article, and others like it, online at www.futurumcareers.com Li’s research takes him to places all over the world, like Madagascar, pictured here. PROFESSOR ZHENG-XIANG LI John Curtin Distinguished Professor School of Earth and Planetary Sciences Curtin University, Australia. FIELD OF RESEARCH Earth Dynamics RESEARCH PROJECT around the world. Li’s group has been feeding such, Li is working with key partners, including Li and his team are using cutting- this information into supercomputers and Prof David Evans of Yale University, USA, edge techniques to create computer using tools, including artificial intelligence (AI), who specialises in palaeomagnetism and world simulations of how plate tectonics have to mine this data and look for patterns. One geology; Prof Shijie Zhong of the University reshaped our planet over the past 2 billion method of computer simulation is known as of Colorado, USA, who is an expert in the years. 4D geodynamic modelling, which uses physics, digital simulation of the geodynamic system; chemistry, mathematics and geoscience Prof Bruce Eglington of the University of knowledge to model the geographical Saskatchewan, Canada, who specialises in the FUNDER distribution of rocks in three dimensions establishment of global geological databases (3D) – length, width and depth –, then work that allow researchers to apply a big data Australian Research Council out how this distribution changes over time. approach to their studies; and Prof Dietmar These time changes are known as the fourth Muller of the University of Sydney, Australia, dimension (4D). who specialises in marine geophysics and led the development of the GPlates software, WHY IS IT IMPORTANT TO INCREASE WHAT HAS LI’S GROUP DISCOVERED which enables scientists to build 3D models of OUR KNOWLEDGE OF GLOBAL SO FAR? global plate tectonic evolution through time. TECTONICS? Working with other research teams from “Earth’s tectonic evolution has impacted different countries, Li’s team has discovered WHAT ARE THE NEXT STEPS FOR LI’S the formation of the atmosphere, which a piece of landmass from North America that RESEARCH PROJECT? we breath, and the behaviour of the Earth’s stuck to, and subsequently travelled with, Research can be a slow process. In fact, there geomagnetic field, which protects the Australia about 1.6 billion years ago, when both is even a term for this: “slow science”. This atmosphere, the hydrosphere and all life countries were part of the same supercontinent is because it can take years to gather the on Earth – like a giant shield – from the known as Nuna. evidence needed to prove or disprove theories. bombardment of the Sun’s strongly charged Indeed, Li reckons it will take at least another particles, known as the solar wind,” explains Li. The researchers have also suggested that 20 years before he can provide more definitive there might be a “superocean cycle” – which answers to some of the science questions he is By investigating the evolution of tectonic describes the formation and dissipation of huge hoping to answer. plates, Li and his colleagues are furthering our oceans. This superocean cycle is believed to understanding of their effects on landscapes, take place over about 1.2 billion years compared But slow science does not translate into soils, minerals and fossil fuels – all of which to the supercontinent cycle, which takes “boring science”! Quite the opposite, as Li are vital to society in so many ways, from roughly 600 million years to complete. says: “My team is evolving as the project agriculture to energy supply and product evolves, with some younger members moving development. Moreover, knowledge about WHY IS LI WORKING WITH OTHER to other institutions around the world to tectonics is essential if we are to fully RESEARCH TEAMS FROM ALL OVER develop their independent careers, and new understand and survive geohazards such as THE WORLD? members joining us with support from new earthquakes, volcanos and tsunamis. So, while As Li explains, “The scope of this project is funding sources. All of us, along with our curiosity about how planet Earth really works so large that it is crucial to work with a wide other collaborators, are continuing to pursue might get you started in a career in geology range of specialists with knowledge covering all this exciting research field as an expanding or geophysics, your studies in Earth dynamics key disciplines and geographic locations.” As international network.” will underpin life as we know it. 00 ABOUT EARTH DYNAMICS Planet Earth is a sphere, composed of several, kilometres, albeit over a long period of time. each other, a fault line will have formed. distinct layers. The outermost layer is known Sometimes the plates stick and forces build as the crust and is made of solid rock, between Periodically, many of the landmasses join up – eventually the force is released in a 8 and 50km thick. This crust, together with together to form a supercontinent, before violent jerk, causing an earthquake. the topmost layer of mantle under it, forms breaking apart again. This supercontinent cycle a mosaic of rigid plates that float upon a takes place over 500 to 700 million years. WHY SHOULD STUDENTS STUDY mushy layer of the mantle, known as the EARTH DYNAMICS? asthenosphere. Over time, these plates move HOW ELSE HAVE THESE MOVING The study of geology or geophysics can lead around the globe. PLATES AFFECTED OUR PLANET? to a wide range of exciting and rewarding When plates collide, new mountain ranges careers. Plate tectonics have an impact WHAT EFFECT DOES THIS HAVE ON might form between them; when they on the formation of our atmosphere, the OUR PLANET? move apart, new oceans may appear. In Earth’s geomagnetic shield (which protects Everything that we see on Earth, from the some areas, hot, molten rock from deep us from the solar wind – dangerous, highly landmasses that make up the continents and below bursts through in a volcanic eruption.

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