My Story

When I was in high school, I thought I was going to be a performer in musical theatre. I was definitely not going to be a scientist.

I knew that with great certainty from a young age. I talked my way out of the many science requirements which, in retrospect, was not the best idea. I studied music and drama, along with one psychology unit to fulfil the science subject required by the curriculum.

After high school, I started a degree in music at Monash, but immediately knew it was not for me. It wasn't the sort of music that I liked to do and I knew that I was in the wrong place. I thought I'd try psychology, it was the one other thing I liked at school. It went well and I found it interesting, so I went on to work as an experimental psychologist for the Defence Science and Technology Group. I loved that job, doing science every day, but after 5 years I knew that those weren't the science questions that I wanted to answer. I wanted to answer the biggest questions I could think of.

I wanted to know why the universe works the way it does and why we have different planets. I wanted to know how mountains formed and why volcanoes erupt.

Around that time, I got to go to a weird conference called "from stars to brains." They had many presentations from different scientists, starting off with astronomy focussing on the big bang and the first few seconds of the universe. Then it moved on to planetary science and geology focussing on the evolution of the solar system and Earth, and the beginning of plate tectonics. That was the first time I realised geology was something that people did as a career and that you could actually study why volcanoes erupt as your whole career. Straight after that conference, I went back to Monash and enrolled in a graduate diploma in geoscience. Then I basically just kept going.

I now work as an academic in geoscience, splitting my time between teaching and research. I study what happens to rocks when tectonic plates collide. When that happens, the plates either push upwards to form a mountain range like the Himalaya, or one plate will sink or subduct under the other. Tectonic plates are made of solid rock and the only way that solid rock can move large distances and change shape is by using rock "conveyor belts": narrow layers of rock that deform and allow rocks to move past each other. These conveyor belts are called shear zones, and they can move rocks kilometres into the sky! Mount Everest, the Andes, and the European Alps were all uplifted by shear zones. Shear zones are also weak zones in rocks, and fluids are attracted into these weak zones. This makes shear zones pathways that fluids move through and when water moves through rocks it dissolves critical minerals, that is, minerals needed to build green energy technology. These dissolved elements and minerals are transported in shear zones and then form mineral deposits along shear zones. As a result, shear zones have ended up being quite an important part in climate change solutions because these critical minerals are needed to build wind turbines and solar panels.

 When you ask geologists what their hobbies are a lot of them say things like hiking or rock climbing, which kind of makes you feel like you need to like being outdoors to be a geologist. But that's not me at all, I'm much happier curled up on the couch with a good book. One of my hobbies is connecting with people over social media to talk about how cool geology is. I think there are a lot of people like me that never knew geology existed in high school, but would absolutely love to work in this field, so I want to ensure that as many people as possible know about it.

I have a four year old daughter. It's really awesome being a scientist and a mum, because you get to give your kids the gift of a love of science from very early on. On the weekend we do cool stuff like making crystals, volcanoes and slime. When we go for walks together we talk about rocks and it blows her mind when we're walking on crystallized lava or on a beach that dinosaurs used to walk on! People worry that the career of an academic and the lifestyle of a parent don't converge very well, but that's not what I've found. I've found the flexibility of an academic career is amazing for being a parent because you can be there at 3pm when the kids get out of school, and drop them off in the morning.

What secrets can rocks tell us about the universe?

Could you give us an overview of the rock cycle?

The rock cycle describes how rocks change between three main types: igneous, sedimentary, and metamorphic. Igneous are what we call fire formed, they form from volcanic eruptions or through volcanic processes. That includes solidified magma under the earth, or lava that has erupted, cooled and crystallised. Over time, igneous rocks at Earth's surface weather, crack and break down. Individual grains or small bits of rock break off the rock and you end up with a pile of sand grains or sediment. When that sediment is buried the pressure from the overlying sediment cements all those different grains together and it makes a new rock which we then call a sedimentary rock.

Now, if you bury that sedimentary rock down deep within the earth, then the minerals that are within it are no longer stable, because minerals are really sensitive to changes in pressure and temperature. So what happens is that the atomic bonds in the minerals break and form new minerals that are stable at those pressures and temperatures. And that's what we call a metamorphic rock. So a metamorphic rock is when a rock changes its mineralogy as a result of a change in pressure and temperature or due to the addition of water to the rock.

Those are some examples but the rock cycle shows us how each of the three rock types can become the other two. Igneous and sedimentary rocks can get buried deep within Earth and become metamorphic rocks, metamorphic and sedimentary rocks can melt and become igneous rocks, igneous and metamorphic rocks can erode at the surface into grains and become lithified into sedimentary rocks. 

How do plate tectonics aid this?

The theory of plate tectonics is the grand unifying theory of geology. Tectonic plates are bits of the earth's lithosphere: the crust and the uppermost part of the mantle. The solid lithosphere is broken up into plates which move around the surface of the earth relative to each other. Some are colliding, some are moving away from each other, some are sliding past each other laterally. The movement of tectonic plates drives the rock cycle by taking rocks from one environment (e.g., a sandstone on a beach) and putting them in a different environment (burying the sandstone within a mountain belt at high pressure) and this causes rocks to change type (the sandstone becomes a metamorphic rock).

What drives the plates to move?

One driver of plate tectonics is the creation of new crust. In the middle of ocean basins there are huge volcanic chains that mark the place where two tectonic plates meet. These underwater volcanoes are creating new magma, which erupts on the surface and makes new rock. As that new rock is added to the edges of both plates, it effectively makes the plate bigger. The whole system needs to make room for this new addition, and so we get a situation where these two tectonic plates are pushed away from the volcanic chain in opposite directions, kind of like two airport travelators end-to-end, one moving rocks toward the departure gate and one moving rocks to the baggage claim. We call these spreading centres, and this pushing force from the creation of new rocks is one of the forces that moves plates away from each other and drives plate tectonics.

My research on tectonic plates

As an example: 50 million years ago, the Indian tectonic plate and the Asian tectonic plate collided. It was a head on collision and because those are both really buoyant plates, neither one would sink under the other one. This meant they buckled and pushed together, creating a huge mountain chain between them, the Himalayas! I study how rocks push together and form huge mountain chains by movement on shear zones, which are narrow layers of weaker rocks that act like conveyor belts, carrying rocks kilometres into the sky.

Shear zones are important in other tectonic boundaries too. For example, along the San Andreas fault in California the plates are moving laterally, sliding past each other, which we call strike-slip movement. As the plates move past each other, they get stuck and strain energy builds up. Once the strain energy exceeds a threshold, the rocks rupture and an earthquake occurs. These earthquakes don't require a lot of movement to be dangerous. The last rupture of the San Andreas fault involved about 10 m of movement, which created a very destructive magnitude seven earthquake. When earthquakes occur the sudden release of energy causes fluids to move through the rocks, which finds its way to other fractures, which can cause new earthquakes, called aftershocks.

Earthquakes, mountains and volcanoes are all common along plate boundaries. For instance, the Japanese islands are volcanic and formed by plate subduction (where one tectonic plate sinks under another). As that happens, melting occurs and feeds the volcanoes. So most of the time, when one plate subducts under another, there is a  volcanic chain above it.

If shear zones are only in particular places, what drives it in one location and not another?

A lot of people work on that question. The rocks are weaker in the places that shear zones develop. That can be because you have two different types of rocks next to each other which creates a natural boundary. Or, a lot of the time it's a place that has fractured or faulted before. A good example is what happened 550 million years ago in Australia. At that time the continents were in different places to where they are now. India was actually very close to Western Australia and the two collided, forming part of the supercontinent Gondwana. That collision caused a huge mountain belt to form in Central Australia, even though the collision was more than 2000 km away. The mountain belt formed because Central Australia already had a network of broken rocks (faults) from earlier deformation, so it was a weak zone that buckled due to that distant collision. It's incredible to think about because these mountains were like having something like the Himalaya in size in the place where Uluru is now. But now there are only small hills left because the mountains have eroded away.

What can we learn from shear zones?

When water is trying to move through rocks, it often uses shear zones as fluid conduits because those are the weak layers and easier for water to move through. One reason that's interesting is that sometimes mineral deposits form as a result of that process. In Australia there are places where water has moved through shear zones and scavenged important minerals that we call critical minerals. We call these critical minerals because they are needed for green energy technology. For example, solar panels and wind turbines need a lot of critical minerals like tellurium and copper. Globally, we are trying to move towards green energy technology and away from fossil fuels, which means we need many more wind turbines and solar panels. Luckily Australia has heaps of critical minerals, but we just have to find exactly where they are and how to get them out of the ground in a really sustainable, environmentally friendly kind of way. That's a field that a lot of geologists work in and is an important part of our solution to climate change.

Understanding how fluids move through these shear zones is also important because fluids increase pressure in rocks, which causes earthquakes.

There is also a pure science component to it. We really want to understand how the Himalayas were constructed. To do that, we need to understand shear zones in fine detail. We need to look at the tiny crystals within the shear zones, understand how they have formed and how they've changed their shape, how the rock has flowed to create that huge mountain range. So shear zones are interesting in lots of different ways.

Geology combines all sciences

Geology combines many different fields. Even though I'm much more on the physics side of things, I also use chemistry quite a lot. For example, I look at how minerals change their composition during the processes that occur beneath the earth's crust. I look at what happens to the composition of minerals when you add water, or when you bury a rock really deep within the earth and how mineral compositions change in response to that change in pressure and temperature. So that's a big part of my work as well. For some people, their whole world is geochemistry. They can study isotopes in basalts, which are forms of lava. They might be trying to understand how the lava formed by measuring particular isotopes or particular elements within the rocks.

Paleontology is a crossover with biology and zoology. Although they are looking at fossils of animals, that background in biology is important. They need to understand how those animals may have lived and the function of different bones, joints, and features. So when they find a tiny femur fossilised in a mudstone, they can hypothesise what that little nodule at the end of the femur might have meant to the way that bird moved.

We also have planetary geologists. These are people who study planets other than Earth. They need to have some familiarity with astrophysics and astronomy. That's quite an exciting crossover because geologists have a really good understanding of the processes that happen in rocks, while astronomers have a really good understanding of what happens in space. By crossing those over you get a really great understanding of the processes that happen in planets and asteroids. Geologists have even been to the moon- that's how important geology is to space rocks!

Outside of the pure sciences, I use a lot of statistics in my papers which I actually learnt doing a degree in psychology. My psychology degree has really come handy in my geology research! Before I found geology, my area was music and musical theatre-very different to what I'm doing now. But that is another weird crossover, because that experience has made me a better lecturer. I find it easier to engage with the students, I'm a bit more comfortable in that setting. Another example of a great crossover is one of the PhD student's in our school, Ella, and she is an amazing artist. Her science figures are just spectacular. Artists actually do really well in geology because we so often have to draw figures that show our scientific understanding in journal articles. Sometimes we get mature age students in our degrees and they can feel a bit sad that they are late to finding geology, like they have wasted some time and  wish they had discovered geology earlier on. But that life experience does come in handy-you just don't know exactly how yet.

Do you think of yourself as creative?

I don't think of myself as creative in a traditional sense. However, I have been trying really hard to get into science writing for the public. I love good science journalism because it is so wonderful to see science depicted in such an engaging way. That requires creativity because you need to describe things in a way that appeals to people, that is evocative and that they can picture and connect with.

In a way, the job of a scientist is quite creative because you're trying to figure out things on the brink of what's known. We're trying to discover things that nobody else has ever known before. That requires creativity, because you need to see things in a way that nobody's seen before.

Often we say that people who are able to see things in a fresh new way are the ones who make huge discoveries. People like planetary geologists have made a big impact on the astronomy side of things because they bring their knowledge of rocks into the realm of space, where people think differently to geologists.

I think that when we're in high school, we're really quick to silo ourselves as a particular type of person, so that you  feel like you belong somewhere. When I was studying music and drama, I fought with teachers to be allowed to drop all my science subjects. But I was always meant to be a scientist! So why was I so set on not doing any science subjects? I guess I was trying to be a part of this music/drama group and I thought you had to exclude everything else that wasn't music and drama. I think maybe some scientists feel the same way. Like, if you're a serious scientist, you can't also be in musicals. But that is so wrong. If more science lecturers were into musical theatre, then maybe lectures would be a lot more exciting! In reality, your music teacher knows a lot about science intuitively - the science of sound, the maths of music.

Getting women into earth science careers

What does your work look like as an academic?

As a teaching academic, my time is split between teaching time and non-teaching time. During the semesters, I might have three or four classes a week, depending on the unit. During that time, it's a lot of preparation for those classes. I'll go over my lecture, thinking about what I want to say and how I can make it more engaging and fun for the students. Teaching takes a lot of preparation, I'm never just opening up a slideshow and then recording it over zoom or live. I'm always preparing that for hours beforehand, just to make sure that I'm totally on top of what I'm saying.

I do the same for my practical classes. Often, geology is taught as: "here is a rock, here are the minerals in the rock." I like to tell the whole story behind the rock. "This rock is from the Himalayas, and it was part of this big shear zone that uplifted the Himalaya's 55 million years ago. And how do we know that? Let's look at the minerals." I want to get people engaged in the whole story. This is really why we're all here, because of the stories we can tell with science-not because of a pretty quartz crystal.

Then during non-teaching times, I'm doing research. A few years ago I worked on the Greek Island, Syros. They have some rocks there that formed within a subduction zone. While I'm in the field, I look at the rocks, map the rocks and collect samples to then take back to Monash. Once I'm back at Monash, I'll cut the rocks open into slivers that I can then make into microscope slides. I want to see how the minerals have responded to different tectonic events. I might grind some up to make a powder for geochemistry. So I'm looking at the rocks in different ways, through different lenses.

The way I kind of think of it is that I'm a geological detective, I'm getting all these different clues, these different pieces of information, and I'm putting them together to solve this mystery of how places formed. Basically it's clue collection during the day and then I put the story together into a journal article.

You do a lot of work on getting more women into earth science careers, what motivates this?

It is my passion. I do a lot of volunteer work in that space, to support women in earth and environmental science and try to ensure that they don't drop out. Generally in our undergraduate classrooms, we have a roughly even gender split. Then as soon as my students leave my classroom- when they graduate and move into careers- the number of women drops. There are fewer women than men in most jobs to do with geology and in many jobs to do with environmental science as well. Part of what I'm trying to do is help women develop a network of people to turn to, for support and mentoring. I'm part of an organization called the Women in Earth and Environmental Sciences in Australasia, WOMEESA for short. Once you're part of WOMEESA, it's like you have this special badge. And when you run into someone who is also within WOMEESA, it's like you're part of the same gang. There's about 700 of us around Australia, and when you meet another-you're immediately friends, you're immediately on the same side and supporting each other, trying to help each other. It's  a really awesome organization that I love being a part of. In the school of Earth and Environmental Sciences (EAE) we also have the women of EAE network. So that's more of a grassroots thing where we match up our undergrad students with PhD students and staff, to create small mentoring groups. We have seminars and special events, it's all about creating a supportive network for women in our school.

The reason why I do that stuff is because I know my students love earth and environmental science and the women love it just as much as the men do. Something is going wrong when our students enter the workforce. They are dropping out of a career they love because the career is not set up for them. We're trying to fix that so that the women can continue to work in a field that they love. That's the motivation behind it.

In addition to support and mentoring, networks like WOMEESA help to make people feel like they belong. We're telling people "we want you here",  "we want you to do this". That's so powerful because people don't tell you that very often. To have someone invest in you is awesome.

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