How 3D imaging is revolutionising fossil dig sites

Since the term dinosaur was first coined, around 1,000 non-avian species have been described and classified. The exact number is contentious - new findings are constantly emerging - but even so, that’s surely a drop in the ocean compared to how many must have roamed the Earth during their 165-million-year reign. So for the rest of the programme, we’re exploring the many ways that cutting-edge technology is bringing new dinosaurs to light. Because to find a fossil, you need to know where to look. Gone are the days of simply stumbling across a bone sticking out of a hillside. We now understand which types of rock and sediment are most likely to yield fossils.

But with the advent of new imaging techniques, vast landscapes and geological strata can be surveyed at the press of a button, meaning we now have access to almost perfect digital reconstructions of a dig site. Excellent news if you don't want to miss a single sample. One expert in this high-tech kind of expedition is the University of Manchester’s Phil Manning, and I began by asking him what kind of kit ends up in his bag on a 21st century fossil hunt…

Phil - It might sound a little bit strange, but some of the first things I'll put into my bag on a dinosaur fossil hunt will be some very traditional tools. Sort of a hammer, a chisel. We've got some drills nowadays, electricity's been a great boon for digging up dinosaurs, and we tend not to use horse and carts anymore, we've got diggers. But in terms of the much higher tech tech, it is getting a little bit more interesting in how we dig dinosaurs up. In the past 20 years, I've seen a huge use of light detection and range surveying - LIDAR. It's a pulsed laser that you can blast out of the landscape and it records points in space, and basically you can do a 3D photocopy of your dig site, which might be fun just to revisit your site back in the lab, but it is amazingly useful, because as you excavate bones, you can map their relative position as you dig into the ground. So you can create this wonderful 3D jigsaw puzzle post-excavation, and that helps you better understand how those bones were emplaced into that particular shape of sediment. So you think of the rock holding it, it's got a package geometry, as it were, so the shape to that rock and how the bones fit into that shape tell you huge amounts about how they ended up there and what it might mean in terms of the environments, the preservation of the animal, and even where there might be more bones in the future.

Will - How do you get the LIDAR to work though? Because I'm envisaging needing to be quite high up in the air to get a decent idea or a decent amount of scale involved.

Phil - In the past, LIDAR used to be quite bulky. There is airborne LIDAR, but that's relatively low resolution. You're dealing with metre resolution in some cases, which isn't very helpful when you're trying to map dinosaur bones. But ground-based LIDAR, which you stick on a tripod, is quite wonderful. You just move the tripod around the site and you stitch together all the different scans. You have to do the LIDAR dance around the said unit as it rotates, recording the landscape, because you don't want to record yourself, because more 3D Phill Mannings is enough for anyone. But this ground-based LIDAR has gone from a centimetre or so resolution to sub-millimetre now. Not only are we recording where the bones are, you're actually recording in some cases the textures and even colour of the sediment, because you can now overlay photogrammetry. In the same plane as the laser is firing out, there's a camera. Once it's scanned with the laser, the unit does another 360 and it records all of the pictures. It overlays the four colour images on top of your point cloud, so you end up with a three-dimensional, four-colour landscape. It really is like visiting your dig site again.

Will - Is there also the possibility that if you are lucky enough to come across an exposed bit of strata, you can use that to almost map the amount of time from the top to the bottom in geological terms?

Phil - It helps you understand the relative position of fossils within a unit, yes. Timing of events is slightly harder to do, because a single horizon being a millimetre thick could have taken 100 years to lay down, but then a much deeper deposit, say three or four metres, could be a rapidly emplaced crevasse splay where a river bursts its banks. So again, you've got to mix your understanding of the geology, the sedimentology, with the information you're recording with the fossils which you're finding within those units. So you've got to mix the disciplines up to really get a better picture. But there's more you can do now, because the technology that used to happen in the laboratory where you're doing the analysis of chemistry, you can now take units into the that can help you use infrared and also x-rays to better understand the chemistry of the rocks and also the fossils which you're studying. This can be a really helpful tool for doing quite quick and detailed interpretation of these horizons when you're in the field, in the middle of nowhere.

Will - To paraphrase David Norman earlier in the show, back in the day, if you wanted to go on a dinosaur hunt, your means of finding a site was very much serendipitous. So with all these fancy new imaging techniques that you've got, has that given you any kind of leg up on actually being able to find these sites in the first place?

Phil - I'd like to say no. There is still a huge amount of luck involved in discovering dinosaurs in the field, and a lot of hard work actually. It's different depending where you are in the world, but if it's a locality where they don't want to give up their riches too easily, it still involves a huge amount of field walking and a little bit of luck. Actually quite a lot of luck.

Will - It's heartwarming in a way that there's still an element that technology can't improve upon us. But I guess, is that the aspect that you would like technology to go after next?

Phil - I think there are going to be innovative solutions, certainly with the advent of AI being applied to large data sets which were acquired using different imaging technologies. They could search for specific signatures that might aid and abet the identification and later excavation of dinosaurs. So I think the future will deploy these techniques. There's so many other areas of science which are currently being deployed. Archaeologists often get a good kickstart on the paleo. We've all watched Time Team in the past, and it's still running, I believe, online these days. They use ground resistivity tomography, which is this thing called a Schlumberger array. That's basically measuring the resistivity of how much moisture is in the soil, and it correlates to structures beneath the soil. Archaeologists go looking for walls and ditches, but some dinosaur bones are big enough that you could probably use techniques like this, but the resolution isn't so hot. And there's other techniques available as well for looking for bones beneath the ground. But again, it's still being developed. Fortunately, no one has been mad enough to create a giant x-ray machine that will probably dose everyone in x-rays far too much to discover bones beneath the ground. So I think it'd be interesting to see where this technology goes in the future, but I feel quite happy that when I'm at a dinosaur dig site that I've still got to get a sack of plaster, some burlap, some water to encase these beasties so we can drag them out of the field. We're still using techniques that were used 150 years ago, so that gives me some satisfaction, I have to admit.