Speleothem deterioration at Cango Cave, South Africa

Cango is a leading South African show cave that has deteriorated markedly, especially during the second half of the Twentieth century. Little pure and applied research has been carried out at the Cave. The historical record, which goes back two centuries, documents the decline of the bat population, the deterioration of the speleothems especially in the proximal part of the Cave, and the exponential rise in the numbers of visitors. Contemporary observation in Cango I and II reveals that many of the speleothems are covered by phosphate material, and that they are better preserved more distally in the Cave. Despite this trend, there are a few isolated active speleothems near the entrance. This evidence supports the hypothesis that the spectacular speleothems were successively formed in the conventional way, corroded by bat guano, and then covered by new calcite. This recent calcite was eventually dissolved when increasing numbers of visitors were responsible for the development of unfavourable climatic conditions.