Gibbs, H. S., Lowe, D. J., & Hogg, A. G. (1982). Parent materials of Yellow-brown loams in the Waikato-Coromandel district. In Soil Groups of New Zealand, Part 6. Yellow-brown loams. (pp. 12–13). Wellington: New Zealand Society of Soil Science.
Permanent Research Commons link: http://hdl.handle.net/10289/9060
The yellow-brown loams of the Waikato-Coromandel region are derived from weathered airfall volcanic materials. These materials may be either direct airfall deposits, or erosion products of these deposits, described as reworked ash in some publications. In the erosion products small amounts of other rocks may be included in the parent materials, and these additions may modify to a slight degree the chemical and physical properties of the soil as a yellow-brown loam. In larger amounts these additions result in the formation of intergrades to yellow-brown earths or gley soils.
New Zealand Society of Soil Science