Stumped by prehistoric mystery
A huge lump of petrified wood has been fished out of the Mataura River. The lump, believed to weigh about a tonne, was hauled out of the Mataura River last week by a tractor after being discovered in a deep hole.
It’s about a metre long and is a significant find – one that has stumped local man and Hokonui Rūnanga kaiwhakahaere (manager) Rewi Anglem.
“There’s the petrified forest down the Catlins, but that’s miles away. What’s it doing all the way up here?” he said.
The lump was brought to the rūnanga by its discoverer, he said. This was the first time he had come across such a thing from the Mataura River, aside from a much smaller sample uncovered at the same spot a week earlier.
Ex-geologist Richard Bowman of Invercargill said the lump could have originated from a couple of different sources. One source is the lignite measures which surround the Mataura Valley, which would make it about 10 million to 15 million years-old. Small specimens of this type of fossilisation were relatively common, he said.
Another option could be that it is from the Hokonui hills, and about 200 million years-old. This would put it on a par with the petrified forest in Curio Bay.
Without seeing the specimen himself it was impossible to draw any conclusion. Retired Southland Museum director Russell Beck, who had seen a photograph of the specimen, said the source could possibly be from a coal measure or deposit, but he could not speculate without seeing the specimen.
“Unless you know where it occurred, it is hard to know a geological date.” Beck and Bowman both said it was an exceptionally large piece for the area.
Its origins may not be known but the wooden fossil has a certain future – on a display stand at the Rūnanga.
Source: Newslink, Railton Bridget.
Rewi Anglem.