Day two of a weekend study on the fascinating underworld of the "Hypogenic Caves of the North Pennines UNESCO Global Geopark" brought a team from the British Cave Research Association (BCRA) and The North Pennines UNESCO Global Geopark (NPUGG) to the Fairy Hole cave system of Upper Weardale.
The group spent a number of hours exploring this scientifically very important cave. It is believed the ancient Fairy Hole started life as a hypogenic (confined flow) maze cave similar to Hudgill Burn and Knock Fell, also in the North Pennines. Over time it became filled with sand-sized sediment and coated with a thick black crust (likely including manganese).
As the land-surface lowered a surface stream was captured and the sediment was removed along a favoured line - creating the cave system. The most recent phase seems to have been collapse of blocks into the stream passage.
Future trips will seek to discover more about the history of the cave system, of which only part has been explored to date. A BCRA team will be creating video and commentary on the caves to help us better understand the geology underneath the Living Uplands. It is likely the story will be a lot more complicated that the brief description above suggests.