This is a soft-rock karst region with a complex geological history. Karst and caves have formed in both Tertiary limestones and overlying Quaternary calcareous dunes. In addition there is a plateau capped with late Tertiary basalt that has subjacent karst dolines. The edge of this plateau may be a fault scarp.
The longest known cave (3DD-4) currently has about 2 km of stream passage. This is entered at its downstream end via a large collapse doline on the scarp and the stream passage extends back beneath the plateau, whith an spiral pattern so that it circles beneath itself. The cave has numerous mud speleothems.
Exploration and karst studies by the Victorian Speleological Association is continuing. The reports included here are only preliminary.
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Draft cave map of DD-4. Circa 2004, and being actively updated as the survey progresses. Upper levels shown in red. Arrows show stream flow direction Blue = surface dolines. File: 3DD4-map.png |