Ancient fires, ultra-hot rocks and the formation of planets

Thursday 6th April 2023 at 7:45 

Mawson Lecture Theatre
 and FGC supper room
Department of Earth Sciences
North Terrace Campus

University of Adelaide


Lucinda Duxbury, Samantha March and Thomas Burke
Department of Earth Sciences, University of Adelaide

Forum presented by University of Adelaide PhD students

     The student forum has become a regular feature of our programme, giving graduate students from the Department of Earth Sciences an opportunity to tell the FGC about the exciting work that they are doing, and for the FGC to learn how these young and enthusiastic researchers are chipping away at the frontiers of earth science. The forum will take the form of a 15-minute presentation by each of the students followed by discussion with the audience. They will love to have your feedback, and to answer your questions.

Ancient fires: Lucinda Duxbury
     My talk will be about a very hot topic, and I mean that quite literally. The catastrophic fires of the Australian 2019-2020 summer seared themselves into the national consciousness. Now, after rains from three successive La Niña years, our forests are building into ticking time bombs. There’s an urgent need to understand what we’re up against. This is where my stinky lake mud from Kangaroo Island comes in - the mud has accumulated over millennia, each layer containing clues from ancient fires and environments lost to time. What do these remains of the past teach us about the forces that shaped the present? And how will they help us to navigate our future?

Ultra-hot rocks: Samantha March
     What happens to the Earth’s crust when it’s heated to 900 °C? Usually, the answer would be that it melts. However, sometimes it doesn’t! Instead, we might see the most thermally extreme form of metamorphism occur, aptly referred to as ‘ultrahigh-temperature’ (UHT) metamorphism. A lot of minerals (and their isotopic systems) can’t handle the heat, leaving behind zircon and monazite as the most commonly relied on minerals to calculate the ages of these UHT processes. Does this always work though? And if we can’t use zircon and monazite, how else can we understand some of Earth’s hottest rocks?

Very strange meteorites and the formation of planets: Thomas Burke
     Mesosiderites are 'stony iron' meteorites and are among some of the rarest found on earth. They contain approximately equal portions of dense iron material we'd expect to see in the core of a planet, and silicate minerals usually found in the mantle. So, if we can hold these meteorites in our hands on earth, what caused them to be sent scattering across our solar system? How did they form and mix to begin with and did all Mesosiderites come from the same original parent body? We'll explore these questions and more from the wealth of information that these 4.5-billion-year-old meteorites can provide.

Members and visitors are warmly invited to attend and to stay for supper following the meeting.
If the door to the Mawson Building is closed, ring the FGC doorbell to left of the door for admittance.
Note that the doorbell will be removed at 8.00 pm in order not to interrupt the lecture.

Please be warned that there is no wheelchair access to the lecture theatre.

 

Cynthia Pyle will run a workshop before the April meeting. 
The topic for the April 6th workshop is 'TBA'.
 
The workshop will start at 6.30 pm, but people are welcome to come in later, as everyone
works independently or with a friend.

The workshop will be held in the Sprigg Room. Go past the Tate Museum and take the next
staircase on the right. The Sprigg Room is right at the top of the stairs. 
Anyone who arrives after 6.30pm and can't get into the building can ring the FGC bell if it is in place.