Karst in Stone: karst landscapes in New Zealand by Jill Kenny & Bruce Hayward
Geological Society of New Zealand guidebook 13, $12 Reviewed by SIMON NATHAN
Karst landscapes are some of the most unusual in New Zealand – distinguished by steep cliffs, sinkholes, caves, fluted rocks, and disappearing streams. Peter Jackson is fascinated by karst landscapes (although he may not use that technical term), and they appear many times in the Lord of the Rings trilogy. They have also been a favourite subject for many artists, including Leo Bensemann.
Karst is caused by the action of water which has corroded easily dissolvable rocks such as limestone and marble. This booklet gives an overview of karst landscapes in New Zealand, and discusses how they form and the need for them to be treasured.
Although distinctive, karst features are also fragile and easily damaged – by quarrying, subdivision, harvesting of ornamental boulders and the use of sinkholes as rubbish sites. Some karst areas are already protected in national parks or reserves (for example, parts of the Kahurangi and Paparoa National Parks) but there is a real danger that others may be damaged because their distinctive features have not been documented and protected. None of the scientific reserves established to protect geological features include a dedicated karst reserve. And although the Waitomo caves are part of a reserve, the overlying surface karst features which visitors travel through to get to the caves have no such protection. But in a curious irony, the largest Queen Elizabeth II reserve in New Zealand is a karst site on private land near Waitomo.
Corroded boulders are the centrepiece of the Dunedin’s delightful Chinese garden – but the pleasure of this feature is tempered a little by the knowledge that its creation involved the destruction of an area of karst landscape. Does it make it any better that the destruction was in China rather than New Zealand?
Caves are the underground part of a karst landscape. The booklet gives a clear account how how caves form, and how they are related to other karst features such as dolines or sinkholes (or tomo in ) as well as underground resrurgences such as Pupu Springs. Although caves are the least visible type of karst, there is general public acceptance of their importance and fragility, with considerable publicity from caving groups and the tourist industry.
The final section of the booklet, ”Karst your vote”, gives some constructive suggestions about what can be done to protect karst landscapes. One of the most important actions, that can be undertaken by individuals or groups, is to ensure that significant areas of karst are identified as outstanding natural features on district and regional plans. A Appendix gives a list of 184 important karst related sites throughout New Zealand that are listed in the latest version of the Geopreservation Inventory.
The authors have produced an interesting and well illustrated booklet that will surely help the understanding of karst landscapes, and the importance of protecting them.