At the coldest point of the last Ice Age, about 20,000 years ago, we now think the sea was around 120 metres lower than it is today. It came back up in fits and starts over the next 10,000 years. Slide through time and see what might have been exposed between Fishguard and Wexford. The team calls it St George's Land. Nobody has shown it was ever dry enough to walk across.
Illustrative, not to scale. The ice edge follows the team's own LIACARA reconstruction for 17,500 years ago, with full cover at the glacial maximum and the stages in between interpolated. The exposed land is a stylised reconstruction, not a survey. Whether St George's Land was ever fully dry, or a chain of islands and marsh with a channel through it, is an open question in geology. The team's argument is narrower: the sea was far less of a barrier than it is now.
Every scroll takes you further back. Past this summer's expedition, the Vikings, Newgrange and the first farmers, all the way down to a 33,000-year-old reindeer bone from a Cork cave that some researchers think was cut by a human hand. The pink sections denote findings that are still open questions.
Roll the drum back through the nine ages of Ireland. Drag it, scroll on it, or use the arrow keys. Each age tells you what the island looked like, who was about, and what was walking around.
Nobody has ever found Ice Age cave art in Ireland, so nobody knew where to look. Genevieve von Petzinger's team built an AI-integrated research system called LIACARA to narrow the search. LIACARA, the Living Intelligent Archive of Ancient Culture, Art, and Relational Archaeology, brings together archaeological databases, archives, multimedia, and geographic data with artificial intelligence to uncover patterns across time and space. It pulls together everything that is known about the Ice Age landscape, layer by layer, and scores where art is most likely to have survived. That gave the archaeologists a list of candidate sites. Deciding which caves to visit, and what was actually on the walls, was down to the people, not the software. Ireland was the first test. Add the layers yourself and watch the map light up.
The map is illustrative. The real model runs on published datasets and the team's own records, and the eight caves the team shortlisted after visiting are not marked here, on purpose.
In July Jonathan went into a cave in Clare with Genevieve von Petzinger, George Nash, Barbara Oosterwijk and caver Shane Diffily. Seeing everything meant a crawl on his belly through a gap barely wider than a helmet. The cave's location is being kept quiet so nobody goes in and disturbs it.
It's a military crawl. Left elbow, right elbow, left elbow. Tap the two buttons in turn, or use the arrow keys, and pull yourself through. Stop tapping and you stop moving. It's twenty metres. Jonathan says it felt a lot longer.
Get to the end and you'll see the photographs from inside.
The team fed LIACARA everything they know about Ice Age cave sites in south Wales and asked it where in Ireland was worth a look. Using that list and their own judgement, the team checked 28 caves in Clare. Eight had marks worth a closer look, and in the cave Jonathan visited the finger marks were, in the team's words, definitely made by humans. How old are they? That's the million dollar question.
Finger fluting is about as simple as drawing gets. You drag your fingers through the soft white deposit on a cave wall, called moonmilk, and the grooves harden and stay. Moonmilk is a paste of tiny calcite crystals and water that builds up on limestone cave walls, a bit like wet chalk. Some of the flutings in Clare have a crust of calcite over them, which suggests they are very old.
Have a go on the wall. Then picture doing it in the pitch dark with a burning stick for light.
Dr George Nash says there are four main approaches that will be used to analyse the discovery in the Clare cave.
There is no question that what we found here is very exciting. Nothing like this has ever been found in Ireland. But the question is just how old is it?Genevieve von Petzinger, in the cave
One of the biggest things in our field that keeps happening is that we realise things are older than we thought they were.Genevieve von Petzinger, in the cave
There were people in Ireland during the Ice Age. A bear bone from Clare has cut marks from about 12,500 years ago, and that is widely accepted. A reindeer bone from a cave in north Cork, dated to 33,000 years ago, has marks that some researchers read as butchery, though that is still argued over. And somebody, at some point, dragged their fingers through the soft wall of this cave.
The team is investigating the possibility that the marks were made in the Ice Age, somewhere around 15,000 years ago, by people who got to Clare when the sea between Wales and Ireland was far lower than it is today.
Yet to be confirmed with sampling and analysis. It is yet to be proven that a land bridge existed that was significant enough to allow passage on foot from Wales to Wexford. No Ice Age tools or bones have turned up in this cave. That work starts now, and it will take months.
For the record: the team's own paper says an Ice Age date is the strongest reading so far for at least some of the finger flutings, and calls it provisional. The lab work to test it is only starting. You'll hear how it's done, and the arguments about it, in the programme.
Jonathan McCrea goes into a cave in Clare with the scientists who think they've found Ireland's first Ice Age art, and comes out shaking. Forty minutes of moonmilk, arguments and one very tight crawl. Listen live, or catch up whenever you like on GoLoud.
