Monday 10 March 2014

JH in NZ: Loessic intimations of John Hardcastle

JH in NZ: Loessic intimations of John Hardcastle

John Hardcastle (1847-1927) was born in Yorkshire, England. There is some dispute about whether he was born in Beverley, or in Wakefield;  East Riding vs.West Riding. Wakefield is probably right. He went to New Zealand as a child and spent much of his life at Timaru, on the east coast of the South Island. He spent many years associated with the Timaru Herald newspaper. He was a scholar and a scientist and in the years 1889-1890 published two very significant papers on loess.(see Smalley et al.2001).
He had access to the Dashing Rocks section at Timaru, described by J.D.Raeside as the chief candidate to be the type section of the NZ loess. JH was a meticulous field scientist and he recorded his observations on the loess in his papers in the Transactions and Proceedings of the New Zealand Institute. He was a member of the Philosophical Institute of Canterbury, part of the NZ Institute, which met in Christchurch, not too far from Timaru.

His 1890 paper was the first to point out that loess could act as a 'climate register' - the loess contained a record of the changing climate. This must have been one of the first real observations in the science of palaeoclimatology. These climatic observations are being recognized but it is becoming apparent that some other of his observations and considerations deserve to be more fully examined. In the 1889 paper he examined the processes of loess deposit formation and he was the first to propose the breaking down of the process into defineable stages or events. This was not proposed again until 1966, and is still being refined. The event sequence P1T1D1T2D2 should be named the Hardcastle sequence- this is the default sequence for the formation of a basic loess deposit.
P1  formation of material by cold processes in mountains
T1  transportation of material by rivers
D1 deposition on flood plains
T2  aeolian transportation of loess material
D2 formation of open structured metastable loess deposit

This sequence works well for the Timaru loess, with the Southern Alps providing the P1 provenance action. JH was perceptive at the P1 level and was probably the first to emphasize the role of glacial action in loess formation. He reported climatic effects recorded in the loess and in the course of doing so made the first description of a fragipan horizon. The fragipan is a hard, diagnostic soil horizon, associated with loess deposits and essentially named and defined by Guy Smith around 1948. Smith defined it but JH had already provided a beautiful description; the fragipans at Dashing Rocks are impressive and accessible. This first fragipan description should be recognized. JH was also very perceptive on the observation of bird crop stones distributed in the loess; he felt that these had stratigraphic and climatic value- and this is a topic which has not been fully explored even now. Perhaps more pertinent in NZ because moa crop stones are observed and these could offer useful information in various fields.

The Timaru loess should be recognized as a very significant deposit; steps should be taken to preserve and appreciate it. This could be a major geoheritage/geotourism site. The site should be recognized and so should John Hardcastle.  He had an annus mirabilis in 1889-1890 and wrote two brilliant papers which unfortunately were not appreciated at the time Albert Einstein had an annus mirabilis in 1905 and the papers he wrote changed the world. That short burst of brilliance perhaps characterises the outstanding scholar and JH should certainly be seen as outstanding, and given much credit in the development of loess science.

Fagg, R. 2001. John Hardcastle (1847-1927) A gifted amateur.  Geological Society of New Zealand Historical Studies Group Newsletter 22, 21-25.

Smalley, I.J.  1983.  John Hardcastle on glacier motion and glacial loess.  Journal of Glaciology 29, 480-484.

Smalley, I.J., Jefferson, I.F., Dijkstra, T.A., Derbyshire, E.  2001.  Some major events in the development of the scientific study of loess.  Earth Science Reviews 54, 5-18.