Some 300 years ago, the little farming town of Broo in Scotland’s Shetland Islands, Britain’s northernmost group of island, became engulfed in sand after an onslaught of freak sandstorms. Around the mid-1750s, the once-fertile land was riddled with sand and the residents were eventually forced to abandon the town after their homes were obliterated. A reverend visiting the island in 1774 said the area looked like an “Arabian desert in miniature”.
Despite the catastrophic damage inflicted on this small settlement, most of the surrounding farms and communities remained relatively unscathed. Ever since, people have been unsure about what the hell went on all those years ago. It turns out, sheep and rabbits might be to blame.
In a new study published in the Journal of Archaeological Science, a team of geographers, archaeologists, and historians from the Shetland Islands Climate and Settlement Project describe how they have now excavated the site and helped put together some of the pieces of the puzzle.
They used a combination of historical documents, artifacts, geomorphology, and sand analysis. They even used a wind-simulator to observe how far the sands could move in the event of a gusty storm. As shown by the multiple layers of sand, the township's destruction occurred over decades although the final abandonment was probably abrupt.
One of the main drivers of the freak sandstorms was a “Little Ice Age” in the 16th and 17th centuries that caused an unusual amount of storminess in the Northern Isles, the Western Isles, and Mainland Scotland. This shift in climate also caused erosion damage, causing the exposure of more sand on the beaches due to dropping sea levels. These two events combined seemed to be the culprits.
However, other neighboring settlements managed to stand solidly against these storms without too much damage. So what was so different about Broo?
It appears that the shorelines around Broo had a substantial loss of vegetation around the time of the town’s abandonment. The researchers speculate this was caused by sheep overgrazing or an invasive species, such as rabbits, which were brought from mainland Scotland before the 1500s, munching down on all the grass. The absence of this grassy vegetation, which previously kept the sandy shoreline "anchored" together, meant the sand was easily sprayed across the poor town of Broo when storms surged.
That's the theory so far, at least, although the researchers will continue to carry out fieldwork and gather data in a bid to put this enduring mystery to bed.
[H/T Science Magazine]