Christmas Island Karst

The Caves

See also Surface Karst Photos

Selected photographs and diagrams

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Large entrance to a coastal cave - Grimes Cave.
Entrance to CI-20, Most of the coastal caves are entered by swimming from a boat into a tidal entrance. One wades or swims through (fresh) water for much of the cave length
The Grotto (CI-1) has a collapse doline entrance on the Shore Terrace.
Inside The Grotto this daylit chamber is a popular swimming hole. A pool of sea water surges in time with the surf. It is connected by a (dangerous) underwater tunnel to the open sea.
Runaway Cave (CI-2) is a fissure in a major cliff, and possibly due to mass movement rather than true karst solution. The black cable leads to an obsolete water pump.
Rubble in Freshwater Cave (CI-10) sits in a pool of saturated water which has coated it with calcite within the zone of tidal fluctuations. Note uncemented rubble behind the lamp - above the high tide mark.
A row of alcoves in the cliff above the Shore Terrace would have formed at a past stand of sea level, but has been uplifted since.
Jedda Cave (CI-5) is one of the Plateau caves, and has a small stream running through a muddy passage that floods completely each wet season. We measured CO2 levels up to 3% in these plateau caves.

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