By Tracey Matthies
IT’S not just local motorists who are excited by the long-awaited realignment of the South Gippsland Highway near Koonwarra.
Palaeontologists believe the works could give them access to a potentially rich new fossil field, one that could fill many gaps in their knowledge about the paleoenvironment and paleoclimate of the region 120 million years ago.
The highway realignment will also make it safer for experts to work on the site of the existing Koonwarra Fossil Bed.
Discovered in 1961 when road gang workers were, coincidentally, straightening and widening a section of the South Gippsland Highway, the Koonwarra Fossil Bed is, in the words of palaeontologist and Post-Doctoral Researcher at Swinburne University of Technology, Dr Stephen Poropat, “Konservat-Lagerstatte” – a site which preserved fossils in both exceptional abundance and exceptional quality.
And he, for one, is excited by the prospect of learning more from the immediate area.
“We can learn a lot from Koonwarra if we study it more and move more rock to find more fossils,” Stephen told the Sentinel-Times last week.
“If we find fossils of animals and plants other than those already represented in the fauna, we’ll be able to fill in many gaps in our knowledge.”
Stephen, who has written extensively about the site and was a part of the most recent dig in 2018, said there was no other Cretaceous fossil site like Koonwarra in Australia, and few like it in the Southern Hemisphere.
“To have such fantastic preservation of fossil insects and other arthropods in particular is unusual and has shed light on the evolutionary history of many groups still with us today,” he said.
“But it is also important because it preserves the only Cretaceous fossil feathers in Australia, the geologically youngest horseshoe crab in Australia (Victalimulus mcqueeni), one of the oldest fossil flowers anywhere in the world, the wonderful fossil flea Tarwinia australis (one of the oldest fleas known), and the only syncaridan crustaceans known from Australia between the oldest ones (~200 million years old, if I remember correctly; they are definitely Triassic) and those still living in Tasmania.”
Writing in the Australian Age of Dinosaurs magazine, Stephen Poropat retraced early explorations and discoveries at Koonwarra.
Jim Bowler was at the geology department of the University of Melbourne in 1961 when he read in a South Gippsland newspaper about the road workers’ initial discovery. His enthusiasm led to a team from the university visiting the site in January 1962 where “with blasting assistance from the Country Roads Board, they were able to collect numerous fossils”.
The National Museum of Victoria and Geological Survey of Victoria also collected samples in the early 1960s.
Melbourne University research student Elizabeth Carroll described two fossil insects from Koonwarra in 1962 – one as a bee (later reinterpreted as a leafhopper) and the other as a stonefly.
“The following year Jack Douglas from the Department of Mines published a report of a fossil fructification (from a flowering plant) from Koonwarra – a significant discovery as no fossils of flowering plants had previously been found in the Victorian Cretaceous” Stephen wrote.
Early excavation efforts were focused on the northern side of the highway, but this changed in 1966 when two Monash University researchers, a student and his supervisor, gained permission to dig on the southern side. Substantial digs followed in 1966, ’67 and ’68.
The site also drew the attention of keen amateurs, including a senior accountant with the SEC, Peter Duncan.
Stephen said Duncan “became so fascinated with the Koonwarra site that his contributions to the collecting efforts there remain unparalleled”.
Among the many scientifically noteworthy reports to come from the site was that of a horseshoe crab found by Korumburra High School student James McQueen. Although James found the fossil on March 21, 1962, his discovery wasn’t reported by National Museum of Victoria until 1971.
The schoolboy enthusiast was rewarded when the horseshoe crab was named Victalimulus mcqueeni.
Following the initial excitement of the 1960s, dedicated digs were conducted in 1981 and in April 2013 with the last palaeontological excavation taking place in March 2018.
Stephen Poropat wrote about that final dig, a week-long expedition where the focus was collecting blocks of Koonwarra rock for Computed Tomography (CT) and synchroton scanning, in Dinosaur Dreaming 2018 Field Report.
“The hope was that fossils preserved within the rock would be visible in the scan data. This would mean that we could remove large slabs of rock from the site, then scan them at a hospital or the Australian Synchrotron to determine how carefully they should be broken up, if at all,” he wrote.
The team arrived to find the site “hideously overgrown” and faced the prospect of pulling plants by hand and shoveling dirt just to reach the deposit.
“We were all relieved when Gary Wallis, a geologist who had prospected at Koonwarra back in the 1960s and 1970s, joined the team with his tractor. What would otherwise have taken the team a day was achieved in less than an hour.”
The plan was to remove 30-50 blocks, each about 10-15 centimetres deep and about the size of an A4 piece of paper, however, getting the blocks out “proved to be extremely difficult” and the dig resulted in just one block.
“Unfortunately … neither scanning mode revealed anything within the rocks, nor at the surface, even when a fish, feather, plant or invertebrate was easily visible,” Stephen wrote.
There are no current plans for future digs but that could change.
Stephen wrote after the 2018 dig that one potential fossil site identified was so close to the current highway that it was unsafe to work.
“However, it is on a section of that road that will be bypassed by the realignment of the highway,” he said.
“When that occurs in a few years’ time then we should make a major effort to test that locality for its fossil potential.”
With those highway works now underway, paleontologists are watching closely, with high hopes.
Bunurong Coast Education’s education officer Mike Cleeland has been engaged as the geological/palaeontological advisor for the roadworks.
He said any fossil-rich rock found during the works would be stockpiled offsite so museum and university-based experts could examine it closely for any significant fossils.
Read more about Stephen Poropat and the Koonwarra Fossil Bed at https://stephenporopat.weebly.com/uploads/2/4/4/2/24423511/poropat_2018_return_to_koonwarra.pdf.