Stone run

A stone run (called also stone river, stone stream or stone sea) is a conspicuous rock landform, result of the erosion of particular rock varieties caused by myriad freezing-thawing cycles taking place in periglacial conditions during the last Ice Age. The actual formation of stone runs involved no less than five processes: weathering, solifluction, frost heaving, frost sorting, and washing. The stone runs are essentially different from moraines, rock glaciers, and rock flows or other rock phenomena involving the actual flow of rock blocks under stress that is sufficient to break down the cement or to cause crushing of the angularities and points of the boulders. By contrast, the stone run boulders are fixed quite stably, providing for safer climbing and crossing of the run.

Stone runs are accumulations of boulders with no finer material between them. In the Falklands, they occur on slopes of between 1 and 10 degrees, and are the product of mass-movement and stone sorting during past periods of cold climate. They everywhere occur in association with poorly sorted, clay-rich solifluction deposits

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.

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Wikipedia