Opalised fossils provide insight into prehistoric outback NSW

ABC NEWS (Australia)

One in a billion bones becomes a fossil, and even fewer turn into precious opal. Then there’s a choice, should opalised fossils be sold for jewellery, or preserved for scientific study?

Transcript

00:00There are accounts of fossils being excavated from the very earliest days.

00:11There was supposedly a crocodile on the eastern fawn that had been found,

00:17and all red and black, and all of it was just cut and cut for earrings or whatever.

00:24So more miners have a sense of wonderment about the fossils.

00:29A lot of the miners know that when the light touches that fossil in their eye,

00:33witnesses it's being uncovered that that's the first time light's touched that in 100 million years.

00:43When opal buyer Mike Pobin comes to Lightning Ridge in outback New South Wales,

00:47he puts out a sign.

00:49He buys from local miners or runners, people who sell for miners.

00:54When Landliner was here in April, he'd purchased something very rare for an undisclosed amount of money.

01:12He thought they could be opal fossils of shark teeth, millions of years old.

01:17It's believed only 12 others have ever been found in the world.

01:21But I can't say with absolute certainty that they're shark's teeth,

01:24and that's why I've asked Jenny from the AOC to come and confirm or deny.

01:31Sometimes I show her something and she says,

01:33yeah, sorry Mike, that's opal masquerading as something else.

01:36You've been tricked.

01:38Jenny Bramall is a paleontologist from the Australian Opal Centre.

01:42She soon confirmed they were shark teeth.

01:45You know what I really, I mean, sorry,

01:49but one of the things I really love about two of these,

01:54I've got this incredible microstructure that you can see on the inside because they're translucent.

02:00Oh, wow.

02:01I don't often see you stuck for words, Jenny.

02:04No, sorry.

02:05I can't see you and I can't hear you.

02:07I can see and hear you.

02:10Lightning Ridge is home to some of the most visually spectacular opalised fossils.

02:16They provide an important insight into Australia's ancient flora and fauna.

02:21How millions of years ago, Central Australia was an inland sea

02:25and Lightning Ridge was part of a forested flood plain.

02:29To form opal, you basically need two main ingredients, silica and water.

02:34You need the silica to dissolve into the water.

02:37You need the water with the silica dissolved into it to go into a void or a space

02:43and then for the water to gradually leave the space.

02:48So, for example, to soak out through the surrounding rock for the opalised fossils to form.

02:54Firstly, we had to have the fossils preserved underground, super rare.

02:59It happened and then you had to have these very particular conditions

03:03for that silica-rich water to get into the voids that contained and were formed by the fossils.

03:10So, you've got this ridiculously unexpected and rare situation

03:15where two natural phenomena that are stupidly unlikely,

03:20the formation of a fossil and the formation of opal,

03:24are coalescing in these objects.

03:26So, that's just wild.

Category

Transcript

Be the first to comment

Recommended