Boulder choke

A broken concrete stair leads is submerged under a pile of loose rock, blocking the way ahead.
A boulder choke formed by a roof collapse in Skirwith Cave.

A boulder choke is a collection of large rocks or rubble that obstructs the passage of a cave or mine. In order to progress through passages cavers often need to negotiate or clear boulder chokes.

Boulder chokes can be formed by rockfall, massive earth movement, mining debris, or deposition after storms. They may also form in stream-ways, where the debris surrounding rocks and boulders is removed by water. Due to the nature of their formation boulder chokes may be unstable and can prove difficult to navigate and map due to their complexity.[1]

In order to clear a boulder choke the rocks obstructing the passage must be broken up and removed, either mechanically or using a small explosive.[2]

Boulder chokes can present a significant danger to cavers, as unstable boulders can unexpectedly move, potentially crushing or trapping cavers.[3] Also, In caves prone to flooding, the narrow and contorted path through boulder chokes can fill up with water quickly, preventing movement past the choke[4]

References

  1. ↑ "The Cave of The Wild Horses, Kilcorney, Co. Clare, Ireland - The 1983 Extensions" (PDF). www.ubss.org.uk. Retrieved 2015-04-21.
  2. ↑ Craig, David; Daley, Jason. "How Low Can You Go?". Outside Online. Outside. Retrieved 2015-04-21.
  3. ↑ "Three Counties System Connects to Create UK's First 100 Kilometre Cave System". Caving News. Retrieved 2015-04-21.
  4. ↑ "Agen Allwedd". www.mlcmac.talktalk.net. Retrieved 2015-04-21.

External links

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