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Environmental Biogeochemistry Research Group | Research Themes

Ironstone-gossan discrimination
Observation of textures within the iron oxide deposit can be as valuable as a geochemical signature. This study demonstrated how examination of base-metal concentrations alone can be misleading when manganese oxides form a significant constituent of the ironstone, and derived textural and geochemical criteria to discriminate between gossans and barren ironstones.

NICHOLSON, K. (1987). Ironstone-Gossan discrimination: Pitfalls of a simple geochemical approach - A case study from NE Scotland. J. Geochem. Explor., 27, 239-257.

Manganese ores
An international authority on manganese deposits, Dr Nicholson has developed mineralogical, geochemical and statistical criteria to aid metallogenic interpretation of Mn ores. A wide range of studies have investigated supergene, sedex and hydrothermal ores as well as modern analogues in bog and soil deposits and geothermal precipitates. He has also demonstrated the genetic relationships between manganese ores with base metal and precious metal deposits. Mn minerals can therefore be used as a pathfinder to such deposits, and as a palaeo-environmental indicator. See the dedicated Manganese page for full details.

Gold deposits
The recognition of the characteristics of fossil hydrothermal systems is the key to epithermal gold exploration. By applying observations on active and recently extinct geothermal systems, diagnostic criteria have been developed to identify eruption breccia, silica sinters and palaeo-permeable zones of fossil systems. Through such methods at least six Devonian hot-spring systems have been identified in NE Scotland.

NICHOLSON, K. (1988). Geothermal deposits in ancient terrain as a tool in epithermal gold exploration: examples from Scotland. In: McKibbin (ed.) Proc. 10th New Zealand Geothermal Workshop, Auckland University Press, Auckland, ISBN 0-86869-026-0, 151-153.

NICHOLSON, K. (1989). Early Devonian geothermal systems in North-east Scotland: Exploration targets for epithermal gold. Geology, 17, 568-571.

NICHOLSON, K. and AQUINO, C. (1989). Life in geothermal systems. A key to sinter formation and recognition? In: Browne, P.R.L. and Nicholson, K. (eds), Proc. 11th NZ Geothermal Workshop, Auckland University Press, Auckland, ISBN 0-86869-071-6, 143-148.

PARKER, R.J. and NICHOLSON, K. (1990). Arsenic in geothemal sinters: Determination and implications for mineral exploration. In: Harvey C.C., Browne, P.R.L., Freestone, D.H. and Scott, G.L. (eds), Proc. 12th NZ Geothermal Workshop, Auckland University Press, Auckland, ISBN 0-86869-012-0, 35-39.

NICHOLSON, K. and PARKER, R.J. (1990). Geothermal sinter chemistry: Towards a diagnostic signature and a sinter geothermometer. In: Harvey C.C., Browne, P.R.L., Freestone, D.H. and Scott, G.L. (eds), Proc. 12th NZ Geothermal Workshop, Auckland University Press, Auckland, ISBN 0-86869-012-0, 97-102.

NICHOLSON, K. (1993). Geothermal fluids: Chemistry and Exploration Techniques. Springer-Verlag, Berlin 268pp, ISBN 0 387 56017 3.

NICHOLSON, K. (1994). Fluid chemistry and hydrological regimes in geothermal systems: a possible link between gold-depositing and hydrocarbon-bearing aqueous systems. In: Parnell, J., (ed), Geofluids: Origin, Migration and Evolution of Fluids in Sedimentary Basins. Geological Society Special Publication No. 78, Geological Society Publishing House, 221-232.

Hydrothermal systems
Modern terrestrial hydrothermal systems and their deposits have been studied in New Zealand and Papua New Guinea. Hydrothermal alteration assemblages, sinter geochemistry and fluid chemistry have all been examined in a series of projects. See the dedicated Geothermal page for more information.