Saturday, 1 February 2020

Loess in South Canterbury

South Canterbury is in the South Island of New Zealand. It is the region which John Hardcastle wrote about in his book 'Notes on the Geology of South Canterbury'- first published by the Timaru Herald in 1908, and re-published in an edited and illustrated version by Loess Letter in 2014.  South Canterbury contains some interesting loess deposits; the Dashing Rocks section has been examined by many scholars and is probably the best known.  Most of the following illustrations are of the Dashing Rocks exposures. The loess there sits on the Timaru basalt- volcanic material from Mount Horrible which determined the location of the town of Timaru. The Dashing Rocks loess appears to contain three fragipans; is this the only occurrence of multiple fragipan horizons? Fragipans were first observed by Hardcastle in the Dashing Rocks loess.


Most of these pictures are by Roger Fagg of Timaru; a few maps etc included for locational purposes.  The soils at Timaru were eventually classified as 'fragic pallic soils' acknowledging the presence of fragipan horizons.




The John Bruce map of loess soils in the South Island.





John Howarth stands on the Timaru basalt





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