A redating of Northern Ireland's hexagonal column coastline links it to a hemisphere spanning volcanic event whose fingerprints also appear in Greenland, the Faroe Islands, and Scotland.
The hexagonal black basalt columns of Northern Ireland's Giant's Causeway, a UNESCO World Heritage coastline on the Antrim coast, formed in roughly half the time scientists previously thought, according to a study published in March 2026 in the journal Geology, the flagship publication of the Geological Society of America.
A team led by Prof Mark Cooper, chief geologist at the Geological Survey of Northern Ireland, with co-author Dr Simon Tapster, a geochronologist at the British Geological Survey, redated Northern Ireland's Paleogene volcanic activity to a window of about 5.5 million years. That is a sharp reduction from the previously accepted span of roughly 13.5 million years, an 8-million-year compression, according to the British Geological Survey release on the new study and the [peer-reviewed paper in Geology](https://pubs.geoscienceworld.org/gsa/geology/article/doi/10.1130/G54157.1/727758/Feeling-the-pulse-Paleogene-chronostratigraphy-of). In a field where the basic unit of measurement is the million-year, an 8-million-year revision is substantial.
But the new timeline is only part of what the paper does. The study also ties the Causeway's formation, along with the wider Antrim Plateau, the Mourne Mountains, and Slieve Gullion, to the North Atlantic Igneous Province, a massive volcanic event that accompanied the opening of the North Atlantic Ocean between roughly 62 and 54 million years ago, the BGS news announcement reports. Remnants of that province are preserved across West Scotland, the Faroe Islands, northwest Iceland, East Greenland, western Norway, and now, with a tighter date, Northern Ireland itself.
The shift repositions Northern Ireland's volcanic rocks from an apparent outlier to a dated node in a globally linked event. The province may have formed through short, regionally consistent bursts of volcanism rather than a long, diffuse episode, the authors suggest, on the strength of what Tapster described as "cutting-edge analysis" in the BGS release.
The Causeway itself comprises roughly 40,000 interlocking basalt columns produced when intense volcanic activity forced magma up through chalk cracks in the surface. As the lava cooled and contracted, it cracked into the regular polygonal columns that today draw millions of visitors a year to the site, a figure that traces back to Northern Ireland tourism statistics cited in the BGS news item. The hexagonal geometry is a textbook example of cooling-contraction columnar jointing, and the site has been studied, sketched, and mythologized for centuries. The paper's contribution is to the deep clock underneath, not the visible columns.
The methodological takeaway is broader than the Causeway. By redating Northern Ireland's rocks and aligning them with already-dated North Atlantic Igneous Province sites in Greenland and elsewhere, the authors demonstrate a correlation model: a single landmark can be tethered to a hemisphere-spanning event if its geochronology is precise enough. The paper's title — "Feeling the pulse? Paleogene chronostratigraphy of Northern Ireland..." — gestures at that pulse, asking whether the North Atlantic's volcanic record is a coordinated rhythm rather than a scatter of unrelated local events.
There are real limits to the claim. The revision rests on a finite set of radiometric dates, and the paper does not present itself as a community consensus. The Causeway's surface geology has been mapped and re-mapped for two centuries, but the deep chronology still depends on a limited number of samples that have survived weathering and reuse. Whether other North Atlantic Igneous Province sites will compress on the same scale, and whether the regional bursts hold up under independent dating, remain open questions. The "globally significant" framing is a direct quote from the BGS release and the paper itself, not the reporter's word.
What to watch: whether follow-up studies redating the Faroes, East Greenland, or the Scottish exposures converge on similarly compressed windows. If they do, the 5.5-million-year Causeway timeline becomes a regional rule. If they don't, the Causeway is a one-off recalibration in a province that stays broadly diffuse, and the headline gets smaller.
The hexagonal columns on the Antrim coast are the same ones visitors have been walking past for centuries. The pulse they sit on, as best modern geochronology can read it, is faster, and more global, than it looked a year ago.