Cave Type: Inland blue hole - fault line cave
Location: South Andros Island, Bahamas
Length: 2100 m plus
Maximum depth: 98 m
Description: Stargate Blue Hole is located about 500 m inland from the east coast of South Andros Island on the west side of The Bluff village. It is part of a major north-south slump fracture zone paralleling the underwater escarpment that separates the Great Bahama Bank from the Tongue of the Ocean, a deep oceanic trench. This slump fracture extends for tens of kilometers and was formed as a result of glacio-eustatic sea level changes and gravitational stresses along the edge of the limestone banks (Palmer, 1986a & b).
The entrance to this cave is a partially roofed-over cavern with a vertical drop of 6 m to water level. The restricted nature of the entrance limits organic input and as such, the surface water is relatively clear. Underwater, a shaft drops vertically to depths in excess of 80 m, while rift-like passages extend north and south. To the north, a 10 m wide passage with the roof at -20 m depth extends for 107 m to a breakdown choke. To the south, a similar passage runs for 100 m to another choke, passable on the right hand side at -37 m to reach an extremely loose boulder chamber that chokes again after a further 30 m.
Hydrology: Water column profiles were obtained by lowering a Hydrolab Water Quality Multiprobe Logger from the surface to 80 m depth. Surface waters in the entrance pool were found to have a salinity of 3.4 g/l. A halocline between 22-27 m depth marked the transition to 37 g/l salinity. The general temperature trend in the water column involved a decrease from 27.4oC at the surface to 25.0oC at 80 m. However, secondary temperature maxima occurred above and below the haloclines at 10.2 m (25.82oC) and 30.2 m (26.12oC). The pH decreased from 8.7 at the surface to 8.18 at 80 m. A secondary pH minimum of 8.21 occurred at 22-24 m, while a secondary maximum of 8.55 was found at 30 m. Dissolved oxygen decreased from 5.67 mg/l at the surface to 0 at 80 m depth. A secondary oxygen maximum of 2.96 mg/l occurred at 31 m depth.
Diving Mode: Standard cave scuba
History: Original exploration by Rob Palmer.
Fauna: Copepods, ostracods, thermosbaenaceans.
Conservation status: This cave has currently been proposed to the Bahamas Ministry of Agriculture and Fisheries as a marine reserve. The land surrounding Stargate Blue Hole was zoned for residential development until protests lodged by the Blue Holes Foundation resulted in its protection. In 1998, the forest immediately surrounding Stargate Blue Hole was illegally cleared, possibly causing adverse impacts on the cave.
Contributor: Brian Kakuk, Caribbean Marine Research Center, Bahamas
|Please email us your comments and questions.||Last modified:|