Devil's Arrows: Geologists Trace the Stones' Origin to Plumpton Rocks Using Zircon Fingerprints

Overview

The Conversation reports a geologic investigation into the Devil's Arrows, the trio of seven metre tall megaliths near Boroughbridge. A zircon fingerprinting approach links the stones to Brimham Rocks about 18 kilometres away, challenging traditional legends that local stones were used or that Plumpton Rocks were the source.

• Source traced to Brimham Rocks, not Plumpton Rocks or nearby outcrops
• Non destructive sampling by tape lifts of mineral grains to create age fingerprints
• All three megaliths share a consistent fingerprint, implying a common quarry
• The haul distance and landscape context suggest deliberate long distance transport

Author: The Conversation

Introduction

The Devil's Arrows, a triple megalithic alignment standing as Britain’s tallest surviving stone arrangement, has long been woven into a Yorkshire legend about the Devil and Boroughbridge. More than 300 years after the legend was first recorded, a new geologic study published in the Proceedings of the Royal Society A revisits the stones' origin, tracing their source to a distant quarry rather than a nearby outcrop. The researchers identify Brimham Rocks, about 18 kilometres west of Boroughbridge, as the likely source based on a detailed mineral fingerprinting analysis. The finding challenges the assumption that prehistoric builders used the nearest compatible stone and highlights a coordinated landscape-scale construction effort.

Background and Hypothesis

Geologists previously classified the Arrows as Millstone Grit sandstone, a characteristic outcrop in the nearby Pennines. However, the Boroughbridge area sits atop rocks with a different geology, prompting investigators to search farther afield. Plumpton Rocks was initially considered a plausible source due to its similar appearance, but similarity of rock type alone cannot confirm provenance. The study aimed to answer: where did the stones originate, and did builders purposefully select distant material?

Methods: Non Destructive Mineral Fingerprinting

Protecting the prehistoric monument meant the team could not cut, hammer or drill the stones. Researchers instead pressed strips of tape onto inconspicuous areas of each stone. When peeled away, these tapes collected microscopic mineral grains embedded in the stone. Zircon grains, with their exceptional durability and well dated magmatic histories, were analyzed to establish a distinctive age fingerprint for each sample. Over 400 mineral grains from the Devil's Arrows were examined, and all three megaliths produced similar age patterns, pointing to a single geologic source.

ages ranged from approximately 377 million years to 3.7 billion years, with some grains likely originating in Greenland, illustrating a broad crustal provenance for the Millstone Grit that formed these blocks during the Permian period when sediments formed delta-like environments.

Findings: Brimham Rocks Matches

The fingerprint comparison with potential Pennine sources yielded a surprising result. Plumpton Rocks did not match the Devil's Arrows fingerprints, while Brimham Rocks did. Brimham's distinctive landscape features, including sheer grit towers and cup shaped markings in the rock, align with the terrain used by the Arrows. The study notes that Brimham is farther from Boroughbridge than some other Millstone Grit outcrops, signaling deliberate material selection rather than mere proximity.

Archaeological and Landscape Context

The Brimham landscape bears evidence of prehistoric activity, including cup and ring marks and related cup-like markings at the northern arrow. The presence of these markings, together with the fingerprint match, suggests a coordinated effort to quarry, transport, and erect these monumental stones from a distant landscape rather than sourcing from the nearest rock outcrop.

Implications

The results reveal a higher level of organizational complexity in prehistoric stone construction than previously assumed. The Devil's Arrows demonstrate not only technical prowess in moving enormous blocks but also a selective, landscape-scale quarrying strategy. The study demonstrates how microscopic mineral grains can build geological narratives about ancient monuments, offering a model for similar provenance studies of other megalithic structures. The findings also illustrate the value of integrating geology with archaeology to illuminate the science behind the news and the built past.

Conclusion

Geology has rewritten part of the Devil's Arrows origin story. The tripartite stones were likely sourced from Brimham Rocks and moved to Boroughbridge, a distance of about 18 kilometres, indicating a deliberate landscape-based selection of material for a monumental alignment rather than a simple nearest-source haul. This research underscores how modern geochemical fingerprinting can illuminate prehistoric mobility, labor, and landscape use, and invites further interdisciplinary study of megalithic monuments across Britain.