Identify rapid excursions in atmospheric 14C preserved in ancient trees to reconstruct space weather

Synopsis

On the 2 September 1859, 100 million tonnes of charged particles were ejected from the Sun and a few hours later slammed into the Earth’s magnetosphere. What became known as the Carrington Event was truly spectacular. Not only did the Southern and Northern Lights give dazzling displays almost all the way to the equator but power lines burst into flames. The impact of a Carrington-like event today would be catastrophic. Induced currents would topple electrical grids, and satellites circuitry would be fried. The economic cost has been estimated to be on the order of trillions of dollars. The societal impact doesn’t bear thinking about. A major challenge is the short observational record. Fortunately, radiocarbon measurements of tree-rings preserve a global atmospheric signature of galactic and solar cosmic rays at annual resolution.  This is a relatively recent advance in the field. In 2012, Miyake and colleagues were the first to detect a high energy cosmic event at 774-775 CE using Japanese cedar 14C (radiocarbon), an event not obvious in decadally-resolved tree-ring data. Since this time other events have been identified in trees around the world. It has been shown that these rapid and massive excursions are due to rapid changes in solar cosmic-ray flux (often described as Coronal Mass Ejections or CMEs), allowing us to identify Carrington-like events. In this Honours project, a suitable candidate will investigate and measure Southern Hemisphere trees for radiocarbon to identify past CMEs. This is a unique opportunity to work on one of the largest Southern Hemisphere tree-ring collections in the world and undertake radiocarbon measurements at UNSW. You will have the opportunity to learn and apply radiocarbon dating of annual tree-rings in our state-of-the-art laboratory [interactive tour].

Aims

Produce a reconstruction of past Coronal Mass Ejections using atmospheric  radiocarbon preserved in annually-resolved Southern Hemisphere tree-ring records.

Student Benefits

Through this project, you will learn how to design and carry out experiments, analyse and interpret data, and how to write a scientific paper. You will also have the opportunity to learn each step of the radiocarbon process, including sampling, pretreating and graphitisation. You will also become a team member of the Chronos 14Carbon-Cycle Facility as well as the Changing Earth Research Centre (formerly PANGEA), with opportunities for training and career development.

Supervisors: Prof. Chris Turney and Dr Jonathan Palmer