Kath Grey: Discovering ancient life in the Pilbara

Kath Grey talks about her work on some of the oldest fossils on Earth, three and a half billion year old stromatolites from the Pilbara 

Transcript

00:00 Kath

Alec Trendall brought me a couple of samples in 1984. I wasn't really convinced by thm. We finally did a trip in 1994 and we were absolutely blown away.

00:13 Julie

Welcome to The Rocks Beneath Our Feet. In this series, five geologists talk about their years devoted to working for the Geological Survey of Western Australia. From understanding early life, to the tectonic processes that shaped our planet, and making the maps that unearth our understanding of Western Australia’s geology, they reveal their shared passion for discovering the stories in the rocks beneath our feet.

I’m Julie Hollis.

In this episode, Kath Grey talks about her work on some of the oldest fossils on Earth, three and a half billion year old stromatolites from the Pilbara.

00:48 Kath

I got interested in the Pilbara ones in 1984. We're talking specifically now about the ones around Marble Bar, which the rocks there are about 3.4 to 3.5.

01:02 Julie

That’s 3.4 to 3.5 billion years old.

01:06 Kath

They’re sedimentary rocks that haven't been very much altered at all. They're sort of like a little window trapped between the granites, but the rocks themselves haven't been strongly deformed. And Alec Trendall, who was deputy director at the time, brought me a couple of samples in, and I wasn't really convinced by them. They didn't really look like the other ones I knew. They were conical and the laminae weren't particularly well-preserved. Nevertheless, I took myself off a trip and detoured to go and have a look at them.

Unfortunately the vehicle I was traveling in broke down and after we borrowed a vehicle from somewhere else and finally got to this Pilbara locality. And just as we were driving in, we got a message over the radio telling us to go back to Meekatharra immediately because we had to pick the other vehicle up. So I only got about an hour on the outcrop. And I found out later, I hadn't been to exactly the right spot because we didn't have GPS. 

02:10 Julie

Right.

02:10 Kath

It was more by word-of-mouth where to go and look for something. And the bit I looked at, I thought was enterolithic gypsum, evaporites that have been deformed. And it probably was. And it wasn't for another few years that I got back, again by prompting from my Canadian colleague, Hans Hoffman, who managed to get some money to come over and look at them. And we finally did a trip in, it must have been about 1994 I think, where we looked at this area again in more detail and we were absolutely blown away.

And as soon as I saw them I had to reverse my 1984 opinion, much to Alec Trendell's joy, and say, yes, they are stromatolites.

02:58 Julie

Yeah.

02:58 Kath

We could see in the bedding planes of the things, beautiful concentric structures that Hans and I, with all our experience, recognized immediately as being stromatolites. And Arthur Hickman was showing us around as well. And I remember the three of us sitting there saying, you know, “Oh look at these, look at these,” and we saw some huge conical things. They're nearly a meter high,

03:23 Julie

Wow.

03:23 Kath

in a vertical face. And that had us convinced because, like a structural geologist does it, you can see the three dimensional picture from individual bits of them.

03:33 Julie

Yep.

03:34 Kath

Anyway we sat down talking about them and we said, “Well we’ll never convince anybody else unless we can actually produce a three-dimensional structure.” And I can't remember which of the three of us it was but, we're looking down at our feet sort of said, “You mean like these?” and below our feet were what came to be known as the little egg carton stromatolites.

03:55 Julie

Right.

03:55 Kath

And they're perfectly preserved in three dimensions, and we could just see a bit of it poking out from under the overlying bedding plane. And Arthur Hickman sort of said, “Oh look, there's more under here,” and gave the rock a big yank. And there was this tabletop size of these beautifully preserved conical things. And you could see that they’d been aligned by currents and at that locality you can also see how they’re interbedded with the sediments.

Of course working at the survey it was difficult to pursue this.

04:27 Julie

Right.

04:28 Kath

and Hans couldn't get any more funding from, from Montreal University to carry on with the project. So we wrote a paper and then heaps and heaps of other people have come in and done major projects on the area, mainly the Australasian astrobiology group, and then NASA got interested. So there've now been dozens and dozens of papers published on them. But we did this early work.

It was 10 years before we got back to the locality and we got the paper published in Geology. We wrote to all our international colleagues and said look, this is your chance. We haven't got any funding but this is your chance to come out and have a look at this stuff in situ,

05:12 Julie

Yep.

05:12 Kath

because I was so concerned that once we announced the discovery, people would come in and start hacking away at it and taking away, which is what subsequently happened. So we were going on a rescue mission and we decided to remove the little conical things and put them in the museum here.

05:33 Julie

That’s the Western Australian Museum, Boola Bardip.

05:36 Kath

Because a lot of people would go in they wouldn't necessarily know what stromatolites were but they'd be looking for organic material. And we also knew that some of the collectors, the rock collectors, commercial collectors would probably take an interest, which has happened with another site where some of the samples are being sold for jewelry and have completely lost their geological context.

Another thing that I've been involved in is looking at the geoheritage of fossil sites and how to protect them. It's very difficult. There's so many things to take into consideration. For one thing, you need to consider the traditional owners. For another thing, you need to talk to the people who are owning the leases on stations and station country. It's also difficult to get anything through legislation, I discovered. But there really is a need for there to be protection put over key sites, not every site, but a few key ones where it will be devastating if the actual rock faces are destroyed by indiscriminate collecting.

We spent the best part of 20 years trying to get protection for the site. What we found were that many of the overseas university geology groups were wanting to come and collect and do exactly the same project. You know, there were obvious projects that you’d do looking at the carbon ratios and things like that and it was obvious they were all going to go for the same thing, but the outcrop’s only about size of a table top, so it's not sustainable.

07:18 Julie

Yep.

07:18 Kath

So we had a real battle getting that protected. And we ended up getting a ministerial reserve put over it. So anybody who wants to go and collect needs to write to the director and explain what they want to do. It's not hard to get permission to go in and look, photograph and so on,

07:36 Julie

Yep.

07:37 Kath

but taking the rocks away, unless you've got a really, really good viable project, you know, you can't just go in and collect them to stick on your mantelpiece back home. 

Since I've given up working at the survey, the mantle’s sort of passed on and there's a group now based with the Astrobiology Centre in the University of New South Wales, and they're following up on getting more protection done over the area. It's still ongoing. I'm glad to see somebody else taking over. But I'm pleased to see they’re making progress. One of the things we're hoping is that they'll be able to get some wardens from the local Aboriginal communities to try and safeguard them because if they go from the site then you've lost half your evidence.

Something I didn't manage to bring to fruition was to interest people in a site south of Marble Bar. I once said to Arthur Hickman, “What we really need is a site about a kilometre off the road with reasonably well preserved stuff but one that isn't going to be critical scientifically, that we can easily get a track into for the general public,” who were interested in, this is the earliest signs of life, can go in and see. Unfortunately really I couldn't get enough interest or any funding to make this into a public viewing site with storyboards telling the history of what’s at the site. And I also know that people have been in collecting from that site and they have destroyed some of the critical localities. I haven't been able to go there myself for some years, but at one point there's a beautiful area where you can see the stromatolites growing and then they've been truncated by a lava flow and the stromatolites were killed off.

It would be a really good teaching site. And there are other features that would make it a good viewing site and a break for people traveling up to Port Hedland. We referred to it as the Dawn of Life trail. And I still live in the hope that eventually someday somebody will take it a bit further and it will mean that people can actually visit it. There is some information in the ‘Discovery trails to the Pilbara’ about how to get into it but it hasn't got sort of the detailed information. But there’s also a survey record describing the features we thought should be sort of on the walk trail around. I think that would be a classic. And it would also keep people away from the key scientific sites where so much damage can be done. The main aim is to try and protect these sites because it's critical that you view them as they are and their relationship to the surrounding sediment. 

I took some Dutch students up to the Pilbara to look at these sites. They were from two universities and they were running a joint course in astrobiology, training students for space exploration in the future. 

10:46 Julie

Right.

10:47 Kath

The Dutch students have never seen anything like it. Their idea of going on a field trip was a bike ride over country lanes more or less

10:57 Julie

Yeah.

10:57 Kath

or something of that nature. So the Pilbara was a just amazing to them. But unfortunately it rained, practically from the second day. We visited Shark Bay and then the heavens opened. Roads were closed, the Marble Bar Caravan site where we camped got flooded. It was a total disaster, but we did manage to get in to the Trendall site. But I've never forgotten the look on their faces because I'd been warned by somebody who'd been up there a bit earlier in the year that there’d been a cyclone through and the creek beds had been washed out. So instead of going down a dip and up the other side you drove along and then there was a sheer drop.

11:39 Julie

Right.

11:40 Kath

We got to the first of these washouts and started handing out the picks and shovels and I’d never seen anything like the look on their faces. “What's this for?” You know, “We won't get across the road unless you build it.” So yeah. Yeah, and eventually one of the students suddenly got the message that you know, you didn't just sit back and wait for the lecturers to tell you what was going on or do the things. You had to get yourself from A to B. If you were going to do any geology, and they all got stuck in then and did it.

The student, he was actually from a very deeply religious little village. And the whole trip he was having trouble reconciling the beliefs he had been  taught with what we were saying about the age of the Earth. He came down on the right side. 

Much to my surprise, I came across him a few years later and was doing a PhD at Monash, because he'd been so impressed in with doing geology in WA. I always felt that was a little bit of a success.

12:49 Julie

You’ve been listening to The Rocks Beneath Our Feet. You can discover more about GSWA by visiting dmp.wa.gov.au/gswa or find GSWA on LinkedIn and Facebook. If you like what you’ve heard, give them a follow.