__NOTOC__ Nettlebed Cave is a limestone

cave A cave or cavern is a natural void in the ground, specifically a space large enough for a human to enter. Caves often form by the weathering of rock and often extend deep underground. The word ''cave'' can refer to smaller openings such as sea ...

located in the Mount Arthur region of the northwest South Island of

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

. The presence of ongaonga (''

Urtica ferox ''Urtica ferox'', commonly known as tree nettle and in Māori: ongaonga, taraonga, taraongaonga, оr okaoka, is a species of nettle endemic to New Zealand. Unlike the other species in the genus ''Urtica'' found in New Zealand, all of which are he ...

''), an endemic tree nettle, near the bottom entrance gives the cave its name. Until April 2010, when the nearby Ellis Basin cave system was found to be deeper, Nettlebed Cave was thought to be the deepest cave system in the southern hemisphere. It drops below its upper entrance (Blizzard Pot) to its lower exit (the Pearse River resurgence), and its of cave passages make it New Zealand's third-longest cave. In January 2014 a group of cavers established that the Nettlebed Cave was connected to the Stormy Pot Cave.

Exploration

Nettlebed Cave was first explored by

caver Caving – also known as spelunking in the United States and Canada and potholing in the United Kingdom and Ireland – is the recreational pastime of exploring wild cave systems (as distinguished from show caves). In contrast, speleology i ...

s in 1969 through the dry overflow passage of a large spring pouring into the Pearse River. By 1973 of passages had been mapped. It was not until 1979 that a

flowstone Flowstones are sheetlike deposits of calcite or other carbonate minerals, formed where water flows down the walls or along the floors of a cave. They are typically found in "solution caves", in limestone, where they are the most common speleoth ...

squeeze known as the Hinkle-horn-honking-holes was passed, making further explorations possible. Five successive Christmas expeditions (1979–80 through 1983–84) utilising underground camps at Salvation Hall and Soft Rock Cafe led to the exploration and mapping of a further . In 1986 another cave (Blizzard Pot) was connected with Nettlebed Cave, providing an upper entrance to the system, and made the overall depth from the highest point in Blizzard Pot to the deepest point in Nettlebed Cave. The long-sought-after connection between Nettlebed and Stormy Pot was made from the Nettlebed side on 29 February 2014, at the end of a week-long camp at Soft Rock Cafe. After a kerosene smoke test had previously indicated a likely point of connection, a team of four (Kieran McKay, Bruce Mutton, Gavin Holden and Jonathan Ravens) dug out the rubble from a choked, drafting, rift to reach the bottom of a small muddy shaft. A tight squeeze at the top of this climb was enlarged slightly with a rock hammer to emerge at the bottom of the urinal pitch for the Rover's Return bivvi (a low sandy passage used as a temporary campsite at one of Stormy Pot's further reaches). The team were extremely grateful for the NZSS policy of carrying out all solid human waste. The overall depth of the combined system (from the top entrance, Big Friendly Giant, to the deepest surveyed point in Nettlebed's Midas Chambers) was later confirmed as when an accurate GPS survey of the entrance locations was undertaken in December 2015. As of December 2019, the total surveyed length of Nettlebed/Stormy Pot is .

Pearse Resurgence

The Pearse Resurgence is the source of the Pearse Stream, and is the resurgence point for all caves on Mt Arthur, including all water flowing in Nettlebed Cave (under normal water levels). This has been confirmed by positive dye tests from caves in the Ellis Basin to the south, from Windrift to the west, and from Nettlebed Cave itself. On 21 March 2007, a team of international cave divers set a New Zealand cave diving record by reaching a depth of 177m (581 feet below ground level) in the Pearse Resurgence. In 2011, divers reached depth by placing four decompression habitats along the cave main tunnel but were still unable to trace the source. During the 2014 Wet Mules diving expedition, the Pearse was dived to a record depth of . In 2016, Richard Harris and Dave Hurst pushed the limits of the main spring with a 13-hour dive to explore the "Second Breakfast" passage to a depth of before lights began to implode causing them to turn back. In 2020, Richard Harris and Craig Challen reached a depth of in the resurgence.

References

External links

Caving areas in New Zealand
{{Tasman District Caves of the Tasman District

Exploration

Pearse Resurgence

References

Further reading

External links