John Hardcastle and the Pink & White Terraces

The connections may be a bit tenuous; but we will attempt to make them. John Hardcastle lived most of his life in the South Island, at Timaru, but in 1886 he was living in Napier in the North Island. He was there when Mount Tarawera erupted- and he was moved to contribute a discussion about the event to the New Zealand Institute. One of the most important consequence of the Tarawera 1886 eruption appears to have been the destruction of the Pink & White terraces. The terraces were a famous landmark and tourist attraction in the volcanic part of the North Island; a series of terraced pools formed by the deposition of minerals from volcanic waters.

John Hardcastle 1888.  The Tarawera eruption, 10th June 1886. A criticism of Professor Hutton's (and others') explanations of the cause of the eruption.  Transactions & Proceedings of the New Zealand Institute 20, 277-282.

The Tarawera discussions did not touch on the phenomenon of the Pink & White terraces- that came much later and from an unexpected direction. Robin Wooding(1926-2007) was a very talented scientist, and a grandson of John Hardcastle. He had a long and distinguished career with CSIRO in Australia and DSIR in New Zealand.  He was interested in some observations that JH had made on the Mueller glacier. JH had noticed that a stream issuing from the glacier carried ice particles with it that made a dam trapping a pool of water. The formation of the ice dam retaining the glacial water had certain similarities to the formation of the pool walls in the pink & white terraces, holding back the volcanic waters. Here was a possible mechanism for the formation of the pink & white terraces; perhaps the ice model fitted with the volcanic situation.

John Hardcastle 1920.  Deposition of ice by a glacier spring. New Zealand Journal of Science & Technology  3, 26-28.

We do not know if Robin Wooding finished his appreciation of the JH glacier studies. The mechanism as outlined in the JH paper is realistic, and possibly has not been noted elsewhere. Many of JH's observations have turned out to be original.

Craig T Simmons, D.A.Nield  2009.  The life and work of Robin A.Wooding. Trans.& Porous Media 77, 133-142.

The main areas where Robin Wooding worked were: (1) the discovery of the occurrence of fingers in the context of mono-diffusive convection in a porous medium and an early body of associated papers on convection in porous media, (2) the development of a novel hydraulic model for the catchment-stream problem and (3) the mathematical solution to the problem of steady infiltration from a shallow circular pond that formed the basis for the disc permeameter method. The idea of steady infiltration from a shallow pond brings us round to the pink & white terraces and to JH's observations on the Mueller glacier.