洞窟システム
Boesmansgat
Depth reached by Nuno Gomes on 1996-08-23 as published on his own site; the Mail & Guardian reported 283.3 m in 1996 and a 2002 GUE report quotes 286 m. Treat the bottom depth as about 282-286 m depending on source and water level.
A very deep flooded dolomite sinkhole on a private game farm in the Northern Cape, at roughly 1,500 m altitude. It is known for extreme-depth record dives, including the current Guinness women's record, and is not a public dive site.
Boesmansgat (Afrikaans for 'Bushman's hole') is a water-filled sinkhole in dolomite on Mount Carmel, a game farm near the road between Kuruman and Danielskuil in South Africa's Northern Cape. Divers reach the water by scrambling down from the surface and squeezing through a narrow crack; below it the flooded chamber opens out into a very large, deep void.
The sinkhole is famous for depth. Sheck Exley reached the bottom at 263 m in 1993, Nuno Gomes went to 282.6 m in 1996, and in 2022 Karen van den Oever made the dive Guinness World Records lists as the deepest scuba dive by a woman, 246.56 m. Published figures for the deepest point vary between about 282 m and 286 m, partly because the water level has changed over the decades.
The altitude matters as much as the depth. Because the surface lies at about 1,500 m, air pressure at the lake is lower than at sea level, so decompression has to be planned as if the dive were deeper than the gauge shows; Gomes's 1996 dive was treated as roughly equivalent to a 337-339 m sea-level dive. Dives here are long, multi-gas expeditions with large support teams.
Boesmansgat has also seen deaths. A diver lost in the 1990s was found on the slope at about 270 m by Dave Shaw in 2004, and Shaw died in early 2005 while trying to recover him.
The site is on private land and no public access procedure was found. It should be read as an expedition venue, not as a destination for visiting divers.
地質学
Boesmansgat is a collapse sinkhole in dolomite. Accounts describe a small entrance crack leading into a flooded chamber that widens rapidly with depth, with a silty floor at the bottom.
水、水流、洪水
The water is clear and was about 19 C when measured on dives in 1996 and 2002, but brown mud on the walls absorbs light. A 2002 report noted that the water level had fallen over time, which made older depth markers on fixed ropes inaccurate.
なぜ重要か
Divernet describes Boesmansgat as the third-deepest known sinkhole in the world. It has hosted a series of depth records: Exley's 263 m in 1993, Gomes's 282.6 m in 1996, Verna van Schaik's 221 m women's record in 2004, and Karen van den Oever's 236.04 m (2021) and 246.56 m (2022) dives, the latter recognised by Guinness World Records.
コンディション
About 19 C in reports from 1996 and 2002; no recent measurement found. Visibility was described as clear, with silt on the bottom. The altitude of about 1,500 m changes decompression requirements.
公表資料からの一般的な範囲であり、現在のコンディションではありません。
測量と探査の歴史
| 1988-04-04 | Diaan Hanekom and Nuno Gomes dived to 123 m. [4] |
| 1993-08 | Sheck Exley reached 263 m, the first diver to reach the bottom. [4] [6] |
| 1996-08-23 | Nuno Gomes reached 282.6 m on a solo dive lasting about twelve hours. [4] [6] |
| 2004-10 | Dave Shaw reached 270 m on a rebreather and located the body of a diver lost in the 1990s. [4] |
| 2005-01 | Dave Shaw died during the recovery attempt; his support diver survived with serious decompression illness. [4] |
| 2021-03 | Karen van den Oever reached 236.04 m with support from a South African club. [5] |
| 2022-10-27 | Karen van den Oever reached 246.56 m, listed by Guinness World Records as the deepest scuba dive by a woman. [7] |
入口とダイブサイト
One natural entrance is documented: a small crack, roughly 1.5 m by 3 m, through which divers drop to the water. It is on a private farm and not publicly accessible.
方向確認用であり、ナビゲーション用ではありません。白抜きのドットはおおよその位置を示しています。
参考文献
このページのすべての情報とその出典 (18)
| 情報 | ステータス | 出典 |
|---|---|---|
| Boesmansgat is on Mount Carmel, a game farm near the road between Kuruman and Danielskuil in the Northern Cape. | 報告済み | [1] [2] |
| Area-level coordinates rounded from the published location of the sinkhole between Kuruman and Danielskuil; the exact entrance is on private land.Rounded to 0.1 degree on purpose (restricted private site). | 報告済み | [3] [1] |
| The sinkhole lies at about 1,500-1,550 m above sea level.Gomes's history page gives 1,550 m; GUE gives about 1,500 m; Divernet gives 1.55 km. | 報告済み | [4] [1] [5] |
| Nuno Gomes reached 282.6 m in Boesmansgat on 1996-08-23.Mail & Guardian (1996) reported 283.3 m measured on the descent line; GUE (2002) quotes 286 m for the deepest point reported by Gomes. Water level changes also alter the figure. | 情報源が一致しない | [4] [6] |
| Corrected for altitude for decompression purposes, Gomes's 282.6 m dive is given as equivalent to 339 m at sea level.The history page gives 339 m; the record page gives 337 m. | 情報源が一致しない | [4] [6] |
| On 1988-04-04 Diaan Hanekom and Nuno Gomes reached 123 m. | 報告済み | [4] |
| In August 1993 Sheck Exley dived to 263 m and became the first diver to reach the bottom. | 報告済み | [4] [6] |
| In late October 2004 Dave Shaw reached 270 m on a rebreather and found the body of a diver lost in the 1990s. | 報告済み | [4] |
| Dave Shaw died during the early-2005 attempt to recover that body; his death was attributed to respiratory failure linked to gas density at depth.Secondary account on Nuno Gomes's site; Wikipedia dates the death to 2005-01-08. | 報告済み | [4] |
| Verna van Schaik reached 221 m in Boesmansgat in 2004, a women's depth record.Gomes's page gives 2004-10-25; Wikipedia gives 2004-11-24. | 情報源が一致しない | [4] |
| Karen van den Oever reached 236.04 m in Boesmansgat in March 2021. | 報告済み | [5] |
| Guinness World Records lists Karen van den Oever's dive of 246.56 m in Boesmansgat on 2022-10-27, lasting 8 h 11 min, as the deepest scuba dive by a woman.Divernet (2022-10-30) printed 246.65 m before Guinness verification. | 確認済み | [7] |
| Water temperature of about 19 C was reported in 1996 and 2002.Both observations are more than 20 years old. | 情報が古い可能性があります | [4] [1] |
| A 2002 trip report noted that the water level had dropped over time, so depth markers on ropes placed in the early 1990s were no longer accurate. | 情報が古い可能性があります | [1] |
| Divers drop through a small crack, roughly 1.5 m by 3 m, to reach the water. | 報告済み | [1] |
| Boesmansgat is a dolomite sinkhole. | 報告済み | [8] |
| Divernet describes Boesmansgat as the world's third-deepest known sinkhole. | 報告済み | [5] |
| No public access procedure, fee or permit scheme for diving Boesmansgat was found; the documented dives in 2021 and 2022 were supported expedition-style dives organised with a South African club. | 報告済み | [1] [2] [5] |
確認済み：直接開いた公式または一次情報源による記載。報告ベース：二次情報源のみによるもの。情報が競合：注釈に両方のバージョンを記載。最新情報でない可能性あり：確認できた最新の情報源が古い。
上記のソースをもとに、独自の言葉でまとめています。 修正を報告する