Early Earth evolution

University academics: Associate Professor Patrice Rey, Associate Professor Derek Wyman, Dr Vasileios Chatzaras

The time interval 2.7 ± 0.05 Ga stands as the most dramatic in the Earth’s history. A large number of profound anomalies, from the core, to the mantle, to the crust, to the hydrosphere, to the atmosphere and finally to the biosphere, dresses a compelling case for a period of major re-organization in all the Earth’s envelops. The global changes that took place in the Late Archaean were the prelude to the birth of modern Earth. We developed a robust numerical model in linking the emergence of the continent to the secular cooling of the convective mantle. This work a part of a PhD cotutelle of Nicolas Flament which challenges the common view that the elevation of the surface of the continents was constant through time. In contrast, in seems that the emergence of the continents occurred during the late-Archaean. 

The emergence of the continent in the late Archaean allowed for the coupling between the crustal geochemical reservoir with the mantle reservoir through erosion and subduction of continent-derived sediments. Therefore, the emergence of the continent could explain how the Earth system evolved from a period of crustal-growth (Archaean eon) to a period where crustal growth and recycling balance each other. 

University academics: Associate Professor Patrice Rey, Associate Professor Derek Wyman, Dr Vasileios Chatzaras

In the primitive Earth, a wide range of phenomena including the formation of gold deposits and volcanogenic massive sulfide deposits (VMS), as well as the development of sulphur-supported ecosystems at hydrothermal vents were related to the mobilisation of mineralised fluids through the crust and their channelling toward the surface. Therefore, identifying and characterising crustal-scale Archaean plumbing systems and their tectonic settings is one of the most fundamental problems in Archaean geology and exobiology.

The east Pilbara craton in Western Australia hosts some of the oldest lode-gold deposits, VMS deposits, and traces of biological activity on Earth, all within a few tens of kilometres. It is one of the best-preserved and readily accessible Archaean cratons, a natural laboratory for early Earth processes and a region of unique significance to the world’s geoscientists and geobiologists alike. 

Through ARC funded projects we are decoding, with a multidisciplinary team of researchers, the geological record of the east Pilbara craton. Our tools range from structural geology, to synchrotron radiation X-ray fluorescence to numerical modelling. 

University academics: Associate Professor Derek Wyman, Associate Professor Patrice Rey, Dr Vasileios Chatzaras

Igneous rocks provide key insights into mantle and crustal processes that help to illuminate the planet’s evolution. There remains considerable debate regarding the extent to which early Earth tectonics incorporated processes approximating modern subduction. Our recent research challenges a previously unassailable assumption that mantle plumes three billion years ago resembled the upwellings responsible for the Hawaiian island chain.  This paradigm shift provides new opportunities to resolve persistent challenges concerning how continents were born and how they grew through time. Earth is a “living planet” where tectonics and magmas drive countless inter-related systems that influence climate, create the environmental niches that foster bio-diversity and naturally develop large metal deposits.  The relationships between magma types and deposits of copper, gold or other “green metals” are of particular economic interest as the drive to a low-carbon future accelerates and are the subject of collaborative studies with researchers in Canada and China.