Reasons for doing this project

Aragonite is chemically unstable in the normal cave environment, however it has been reported from a number of NSW cave areas as shown in Table 1.

Table 1: Caves reported to have Aragonite

Cave Area	Caves with aragonite
Jenolan	13
Wombeyan	7
Cliefden	3
Wee Jasper	3
Bungonia	2
Yarrangobilly	2
Colong	1
Jaunter	1
Walli	1
Wyanbene	1

There is surprisingly little scientific literature regarding its occurence in NSW caves.

There are a number of chemical and physical factors which affect the stability of aragonite in the cave environment. These include:

• humidity
• air movement and
• presence of calcite inhibitors (Morse, 1983) such as:
  • magnesium
  • manganese
  • sulphate
  • phosphate

Aragonite can deposit at the expense of calcite when a calcite inhibitor is present.

Other workers have mentioned strontium, temperature, rate of deposition or CO₂ concentration as being influential in the deposition of aragonite however the views are sometimes contradictory.

In limestone areas where aragonite has been reported, bulk sampling of the bedrock by the Mines Dept. has often shown high purity of limestone with insignificant concentrations of impurities.

The best aragonite seems to occur in those same limestone deposits in small areas featuring what is usually termed by cavers and cave guides as ``rotten rock''. Some of these sites at Jenolan have been described by Dr Osborne (Osborne, 1993 and 1999).

Identifying aragonite sites and their substrates may help to determine reasons for the aragonite occurence in these areas. It may also help to determine some of the geological events that have happened since the limestone was originally deposited.