Collaborative Research: Reconstructing the Archean Supercraton Vaalbara using zircons and paleomagnetism

Plate tectonics shapes almost every aspect of Earth’s surface today. Earth is the only known planet with active plate tectonics, which may be a key ingredient in its ability to support life. This is because plate tectonics is essential in creating continental crust, cycling nutrients, and regulating climate. However, the timing of plate tectonics' initiation in Earth's 4.6-billion-year history remains uncertain. In this project, the team will study some of the oldest remnants of ancient continental crust, known as cratons, found in parts of Australia and South Africa. More than 2.7 billion years ago these two cratons may have been connected as part of the first “supercraton”. The team will address the evidence for plate tectonic motion and processes of continent formation by reconstructing the formation, evolution, and break-up of this proposed supercraton. They will measure magnetic signatures preserved in rocks and compare the ages of samples of the mineral zircon from the two cratons. These two methods will help them to reconstruct where these parts of Australia and Africa were on Earth at different points in time. These observations will help them determine when plate tectonics began on Earth and how it evolves. The research will investigate the long-debated existence of the Vaalbara supercraton, composed of the Kaapvaal and Pilbara cratons. The team will test a possible correlation between the two cratons by comparing the ages, isotopic and trace element compositions of zircons from sandstones and modern rivers across the two cratons to provide and compare comprehensive pictures of each craton’s crustal evolutions through time and space. The team will compare the latitudinal positions and rotational histories through a paleomagnetic study to fill in several hundred-million-year gaps in the continental drift record of the two cratons. By integrating these two methodologies, the research will mitigate the uncertainties of each approach and create an unparalleled dataset for each craton. The research results will be disseminated through articles in journals, presentations at conferences, and submission to online databases. The team will train PhD students and provide research experiences to undergraduate students. While working in the field, the team will collect video for outreach. They will collaborate with a natural history museum to provide a professional development course for local teachers. This project is co-funded by the Chemical Evolution of the Solid Earth and Volcanology Program and the Structure and Physics of the Solid Earth Program. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria. NSF Award ID: 2425868 | Program: 01002627DB NSF RESEARCH & RELATED ACTIVIT | Principal Investigator: Alexandra Davatzes | Institution: Temple University, PHILADELPHIA, PA | Award Amount: $80,965 View on NSF Award Search: https://www.nsf.gov/awardsearch/show-award/?AWD_ID=2425868 View on Research.gov: https://www.research.gov/awardapi-service/v1/awards/2425868.html