Trace elements in three soil monosequences and iron-manganese concretions from Westland and Canterbury, New Zealand
Degree GrantorUniversity of Canterbury
Degree NameDoctor of Philosophy
This work is a study of the first row transition metals Ti, V, Cr, M, Fe, Co, Ni, Cu and Zn in three soil monosequences and iron-manganese concretions. Three wet chemical decomposition techniques, to be used for the dissolution of soil samples, were assessed. Analysis of the resulting solutions for the transition metals, except Ti, by atomic absorption spectroscopy was compared with the analysis of solid samples by X-ray fluorescence. The transition elements were also determined in three International Rock Standards, and spiking experiments were used to determine recovery of these elements after sample decomposition and analysis. The three monosequences studied were selected in order to examine separately, time, the biotic factor and topography as soil forming factors as soil development proceeded. The soils studied were from the Reefton area and Bealy catchment of the South Island of New Zealand. Data for the chronosequence soils were presented on both a mass per mass and mass per volume basis to facilitate a meaningful comparison of the trace elements, in soils of widely varying properties. Both chemical and mineralogical studies were carried out on iron-manganese concretions from an Irwell pasture in Canterbury, New Zealand. This data, together with data obtained from electron microprobe analyses, was used to demonstrate trace element enrichment in the concretions. It was found that Co and Zn were the trace elements most strongly enriched, and that generally, the transition metals were enriched more strongly in the Mn phases of the concretions than in the Fe phases. An analysis of possible explanations for this leads to the suggestion that sorption of trace elements on to Mn and Fe oxides is probably the major factor.