Tasmania may have been connected to the west coast of America hundreds of millions of years ago, according to a new geological study.
Subscribe now for unlimited access.
$0/
(min cost $0)
or signup to continue reading
A study published in Geology suggests the two landmasses were joined as part of the supercontinent Rodinia, which formed around a billion years ago.
The study was led by Monash University research fellow and UTAS graduate Jack Mulder, who spent years researching the geology of Rocky Cape.
“People have been looking at the rocks in north western Tasmania for a number of decades now and essentially what they realised is those rocks looked different to the rocks that are a similar age elsewhere in Australia,” Dr Mulder said.
“The next question was, where else in the world could we find similar rocks?”
An international search eventually led the research team to the United States, where they spent a year working around the Grand Canyon and Arizona.
The researchers examined the layers of sedimentary rock to understand their composition and the environment they formed in.
They then analysed grains of the mineral zircon, which were eroded from older rocks, transported through waterways and deposited in the layers of mud and sand that make up sedimentary rock.
Dr Mulder said they were able to date the zircon through the radioactive decay of uranium within the mineral and analyse its chemistry.
“So essentially when we did that on the Tasmanian rocks and compared them to the Grand Canyon, it was a very close match. The zircon was essentially the same,” Dr Mulder said.
Dr Mulder said the next question was how Tasmania travelled from the US to Australia when Rodinia started to break up around 700 million years ago.
“We think that probably happened when the Pacific Ocean began to open. Tasmania got plucked off the US,” he said.
The study involved around two dozen researchers and around five years worth of research.