Stone Run - Geographic Distribution

Geographic Distribution

Best known for their exceptional diversity, size and abundance are the stone runs of the Falkland Islands, and the stone rivers of Vitosha Mountain, Bulgaria. The highly specific combination of particular climatic conditions and rock varieties that existed there during the Quaternary explains both the formation of stone runs in those two territories, and their absence in areas with otherwise comparable nature conditions.

For instance, while the present Falklands climate is quite similar to that of Scotland the latter was completely glacial rather than periglacial during the relevant period, which would not allow for the formation of stone runs. On the other hand, due to geological and other specifics of the southern temperate and sub-Antarctic territories with climatic history similar to that of the Falklands (Prince Edward Islands, Crozet Islands, Kerguelen Islands, Macquarie Island, Campbell Islands, or nearby Tierra del Fuego and Patagonia), none of them features landforms even remotely comparable to the Falklands stone runs.

Likewise, the specific geology of Vitosha accounts for the fairly restricted examples of similar landforms in other Bulgarian or indeed Balkan mountains with comparable climatic record among which Vitosha is one of the smallest, extending just 15 km (9.3 mi) by 10 km (6.2 mi). However, even on that small territory the stone runs exist along with screes and other rock landforms, suggesting that the right periglacial conditions and rock composition are necessary but not sufficient conditions for the formation of stone runs.

Other examples of stone runs occur in England, most notably at the Stiperstones, Shropshire. They are also known in Pennsylvania. Small examples are probably very widespread where solifluction deposits contain large concentrations of frost-resistant rock blocks.