Stonehenge altar stone origins and 700k-year coprolite DNA archive: ice-age routes and ancient DNA clues

Overview

In this Nature Friday Briefing, Benjamin Thompson and Nick Petridge discuss two science stories from the Nature Briefing. The first reexamines the origin and transport of Stonehenge's altar stone, proposing an ice assisted route that may have moved a massive rock from northern Scotland toward southern England, with intermediate deposition at Dogger Bank before settlement at Stonehenge. The second story analyzes 700,000-year-old coprolites found in Canada’s Yukon that preserve DNA from mammoths, bison, horses, big cats and insects, offering a remarkable window into ancient ecosystems through the feeding traces of ground squirrels.

• Stonehenge altar stone origin and possible ice driven transport from Orcadian basin
• Ice flows and Doggerland as part of the stone’s journey and the timeline around Doggerland’s existence
• Coprolites as a time capsule containing ancient DNA from mammoths and other megafauna
• New lineage hints for Arctic ground squirrels and the potential for a forthcoming mammoth DNA study

Stonehenge altar stone origin and ice age transport

The podcast discusses a Stonehenge related story that traces the altar stone—the central 6 ton, 16 foot long slab—to its geological origins in the Orcadian basin, northern Scotland. Previous work had suggested a Welsh origin for much of Stonehenge, but the altar stone appears to have originated far to the north. The hosts recount how researchers propose that the stone could not have moved simply by walking along a land route given the terrain and climate of the era. Instead, the analysis points toward an ice assisted transport hypothesis in which glacial processes carried the stone part of the distance toward southern Britain. The discussion emphasizes the complexity of Britain's last Ice Age, noting that ice may have moved the stone southeast rather than straight south, potentially depositing it at a location like Dogger Bank before it was moved again toward its final position at Stonehenge.

The hosts highlight a timeline challenge: the Dogger Bank region and Doggerland disappeared as sea levels rose, meaning the stone’s voyage must occur before those lands were submerged. This places the movement well before Stonehenge was assembled, raising questions about the social or ritual significance of the stone and the cooperation required across communities to move such a heavy monument across long distances after a long interval in the landscape.

Ice age routes and the Doggerland puzzle

The conversation turns to the implications of glacial dynamics in shaping Neolithic mobility. If ice flows contributed to the stone’s partial journey, what routes might have been used to complete the rest of the distance to Stonehenge? The Berkshire Ridgeway, an ancient Neolithic trail, is mentioned as a potential corridor for later stages of the journey. The discussion underscores the need for more precise sourcing and pathway reconstruction to understand why such a monumental effort was undertaken in the first place and what this reveals about social organization at the time.

700,000-year coprolites reveal a mammoth DNA archive

The second part of the podcast shifts to another deep-time inquiry: coprolites excavated in the Yukon in areas affected by permafrost and ice melt. Fossilized dung from ground squirrels is found to contain DNA traces from ground-dwelling megafauna including mammoths, bison, horses and big cats, along with plant and insect DNA. If the dating holds, these 700,000-year-old deposits could extend as far back as 17,000 years ago, creating a long archive of mammal and ecosystem DNA that predates the last glacial maximum in the region. The hosts explain how such coprolite DNA offers a concrete window into past communities and environmental conditions, acting like a time capsule in which carnivore and herbivore interactions, habitat use and dietary breadth can be inferred from fragments within the squirrels’ meals.

The narrative also covers the origin of some of the DNA signals. While mammoth DNA is a key component, the coprolites also reveal DNA from North American cheetahs or pumas, suggesting broader faunal presence in the region. An unexpected twist is the suggestion that the rodent DNA may come from an Arctic ground squirrel lineage related to long-tailed species found in Siberia and parts of Asia, hinting at historical biogeographic connections. The researchers anticipate a forthcoming mammoth-specific paper and emphasize the potential for these coprolite archives to illuminate animal distributions, diets, and ecological networks over hundreds of thousands of years.

Implications and future work

Across both stories, the hosts reflect on how stories from the deep past can reshape our understanding of human mobility, ritual significance, and the broader ecological context of ancient life. They highlight the continuing mystery around Stonehenge, the various routes and social collaborations required to move a colossal stone, and the tantalizing possibility that Doggerland and Dogger Bank played a more active role in Neolithic transport than previously appreciated. On the coprolite front, the Yukon archive could revolutionize our understanding of the Pleistocene fauna of North America and the faunal connections across continents, while also challenging dating methods and interpretations of ancient DNA evidence. The episode closes with links to the two stories for readers to explore further and notes about subscribing to Nature Briefing for more science news and insights.