Mineralogy and origin of the Yellow-Brown sands and related soils Journal Paper
- Author
- Claridge, G.G.C.
- Year
- 1961
- Journal / Source
- New Zealand Journal of Geology and Geophysics
- Volume
- 4
- Pages
- 48-72
- Summary
- Soils formed from wind-blown sand are found throughout New Zealand. In order to study their genesis the mineralogy of a large number of these soils from the Manawatu, Waverley, Dargaville, Ruakaka, Ahipara and the Canterbury Plains has been examined. The Manawatu and Waverley soils were similar in clay mineralogy, the clay minerals being micas, hydrous micas and vermiculite, with traces of halloysite. The pattern of clay content was consistent with the theory that most of the clay in these soils is derived from loess-like material blown in from the beaches after being eroded from older soils in the vicinity. A similar picture was found in a sequence from Dargaville, for the younger soils which were clearly wind-blown and had a clay mineral distribution very like the Manawatu soils. The older soils, however, appeared to be derived from water-deposited rather than wind-blown sand, and contained kaolin and gibbsite, but these also were derived from the sediment and not formed in situ. The Ruakaka soils were very similar to the youngest members of the Manawatu soils, except there was a little more kaolin because of the greater prevalence of kaolin in the soils of North Auckland. Although only one site was examined from Houhora in the far north, and so no sequence was possible, the one profile examined could be related to the Dargaville sequence. The Canterbury Plains soils are derived from sands of river origin as well as marine sands, but the similarity between the soils showed that all these sands must have a common origin. The mineralogy differed from that of the North Island sites in that the dominant clay mineral was clay vermiculite but this was to be expected as this mineral is more prominent in the soils of the hill country from which debris and clay is carried by the rivers.