Sinkhole
Fossil Cave (Green Waterhole)
Cave: CDAA site rating [1] [2] [3] (Cave-rated divers must stay above 13 m and not pass the signed restriction into the phreatic passage.). Advanced Cave: CDAA site rating [1] [2] [3] (Beyond the signed restriction / deeper than 13 m in the phreatic passage.). These categories are the named scheme's own; they describe the training a site calls for.
A state-managed sinkhole pool near Tantanoola that is the second natural entrance to the Tank Cave system. CDAA Cave-rated divers may enter to 13 m in the phreatic passage; deeper is for Advanced Cave divers.
Fossil Cave, long known as the Green Waterhole, is a small pond that opens into a broad chamber floored with dark silt, with a second small pool and chamber at the far end. It sits on state land managed by the Department for Environment and Water and is booked through the South Australian parks booking system.
The CDAA states that a 2018 exploration connected Tank Cave to Green Waterhole, so this entrance is part of the wider Green Waterhole - Tank Cave system, including the fossil deposits at its western end.
The environment
Fresh groundwater in a sinkhole pond and chamber with fine dark silt; the phreatic passage continues deeper beyond a signed point.
Other entrances to Green Waterhole - Tank Cave system
For orientation, not navigation. Hollow dots are approximate.
Every fact on this page, with its source (9)
| Fact | Status | Source |
|---|---|---|
| The CDAA directory rates Fossil Cave (5L81) Cave and Advanced Cave, with DEW as manager. | Verified | [3] |
| Fossil Cave requires a CDAA Cave qualification, and divers must not go beyond 13 metres into the phreatic passage unless qualified to Advanced Cave level. | Verified | [1] [2] |
| Each diver completes a diving indemnity before booking; bookings need at least two divers, at most two dives per day are permitted, and divers may not dive until they receive a confirmation email. | Verified | [1] |
| The CDAA directory says bookings must be made at least 48 hours before the timeslot and allows a maximum of five divers per timeslot including instructors. | Verified | [2] |
| Fossil Cave timeslots are 8am-10am, 12 noon-2pm and 4pm-6pm.CDAA directory page, undated; confirm in the DEW booking system. | Verified | [2] |
| Tank Cave was connected to Green Waterhole in 2018. | Verified | [4] |
| Fossil Cave was formerly known as The Green Waterhole; the name was changed in 1989.Wikipedia, citing the SA Government Gazette of 4 May 1989; the gazette itself was not opened. | Reported | [5] |
| Coordinates are the Tantanoola locality centre, not the entrance.Area-level point. | Verified | [6] |
| Coordinates are the Tantanoola locality centre, not the entrance.Area-level point. | Verified | [6] |
Verified: stated by an official or primary source we opened. Reported: from a secondary source only. Sources conflict: the note gives both versions. May be out of date: the newest source we found is old.
Written in our own words from the sources above. Report a correction