Seeing fish through rocks

Dr Kate Trinajstic has used synchrotron light and CT scanning to see through rock, in the process discovering how ancient fish developed teeth, jaws and even a womb. Her work is increasing our understanding of how life on Earth evolved.

Seeing fish through rocks
The winner of the 2010 Malcolm McIntosh Prize for Physical Scientist of the Year, Kate Trinajstic. Credit: Ron D’Raine
About 380 million years ago in what is now the Kimberley Ranges in Western Australia, a vast barrier reef formed. In what would have been the inter-reef basins, large numbers of fish were buried relatively intact. Protective limestone balls formed around them and preserved them. When these balls are treated with acetic acid, the main component of vinegar, the surrounding rock dissolves, leaving only fossilised fish bones.

But in the course of studying hundreds of these dissolving balls, Kate began to see what looked like muscle fibres between the bones. She was eventually able to convince her colleagues that irreplaceable soft tissue detail was being lost in the acid treatments.

To study the fossil fish without destroying this information, Kate turned to x-rays and the latest imaging technology using the synchrotron. Working with museum and university colleagues, perhaps her biggest discovery has been the ‘mother fish’ with an umbilical cord still attached to its embryonic offspring. This was a vertebrate giving birth to live young some two hundred million years earlier than previously thought.

In 2010, Kate’s work led to her being honoured as Australia’s Malcolm McIntosh Physical Scientist of the Year. She is now looking for biomolecules—remnants of muscle and bone proteins—and also developing tools for the oil company Chevron to help it date core samples rapidly and accurately.

Photo: Kate Trinajstic, winner of the 2010 Malcolm McIntosh Prize for Physical Scientist of the Year

Credit: Ron D’Raine

Chemistry Department, Curtin University, Katherine Trinajstic, Tel:,