By Kirra Grimes
GEOLOGISTS and palaeontologists were back digging at Koonwarra recently, but this time, they weren’t looking for fossils.
The purpose of the week-long visit was a “paleontological engineering dig,” part of an experimental exercise in excavating and examining rock fragments in more efficient ways.
The team of Museums Victoria, Swinburne and Monash University staff and volunteers attempted to excavate large slabs of rock that could be examined internally without being broken apart, thereby minimising the time and labour involved in future fossil digs.
The excavated slabs will undergo various types of imaging, such as neutron scanning, imaging by the Australian Synchrotron, and even by a hospital CAT scan machine.
“The idea is to collect large blocks of rock and image it and see what’s inside, rather than splitting it up and examining every single fragment individually, which is a huge amount of work,” explained, senior curator of Vertebrate Palaeontology at Museums Victoria Dr Thomas Rich who was in charge of the dig.
The fossil bed the team was working on east of Koonwarra, beside the South Gippsland Highway, has turned up many fossilised fish, plants, insects, and feathers from birds since its discovery by road workers in 1961.
Dr Rich first visited the site in 1982 but it wasn’t until decades later that he really became interested in digging deeper.
“In 2009, I was at a dig at Lianing in north east China and I looked at the rock and thought ‘this looks like Koonwarra’. The rock was very geologically similar to Koonwarra and in it they’d found dozens of fossilised fish and feathers from feathered dinosaurs.
“They were the same kinds of fossils that had previously been found at Koonwarra. We haven’t found as many here but we haven’t done as much digging.”
If an efficient method can be found, Dr Rich would like to excavate 50 to 100 tonnes of rock from the Koonwarra site.
“We’re trying to develop techniques to speed up the process. If one strategy doesn’t work, we’ll try another one. It’s about figuring out how to do a dig on a massive scale in the most efficient way,” he said.
Also while on site at Koonwarra, the team started looking into another potential excavation site, a continuation of the mudstone fossil bed about one kilometre west of the original dig site, recently mapped by geology Professor Mike Hall of Monash University.
While some interesting fossilised plants were found during some preliminary digging, Professor Hall identified an even more promising excavation site further down the road.
As this site is on a very dangerous section of the Black Spur curves, Professor Hall says they “won’t be digging there for a while”, possibly not until the Black Spur realignment is complete and the old road closed to traffic.