Roser, B.P.; Johnston, M.R.; Christie, A.B.; Turnbull, R.J.; Brathwaite, R.L.; Allwood, K.J. 1994 Sheet QM340 Motueka : geological resource map of New Zealand 1:250 000. Lower Hutt: Institute of Geological & Nuclear Sciences Institute of Geological & Nuclear Sciences science report 94/16 90 p.
Abstract: The area shown on Sheet QM340 Motueka contains a large variety of minerals, both metallic and non-metallic. It was the scene of the first major alluvial gold rush, to Collingwood in 1857, in New Zealand. Chromite was extracted from the 'mineral belt' of east Nelson in the 1860s. The sheet area has been a significant producer of a number of minerals in addition to alluvial gold, including aggregate, asbestos, building stone, chromite, clay, coal, dolomite, iron ore, limestone, marble, reef gold, serpentinite, and talc-magnesite. Other minerals and mineral groups present include barite, copper, fluorite, graphite, lead, molybdenite, nickel, platinum-group metals, silica sand, silver, tungsten, wollastonite, and zinc. Current mineral production is restricted to aggregate, clay, coal, dolomite, limestone, rock for ornamental use and protection works, and minor alluvial gold. The region is geologically complex, with several assemblages of Paleozoic and Mesozoic sedimentary and volcanic rocks intruded by granite, diorite, gabbro, and ultramafic rocks, which are geologically favourable for hosting a variety of base and precious metal deposits. The recently discovered gold-quartz mineralisation in a peralkaline granite dike at Sams Creek has potential for future mine development. Mineral exploration is currently at a low level because of a number of factors including environmental constraints. However, the wide variety of minerals present in the map area, the recent discovery of the Sams Creek gold deposit, the apparent high prospectivity of the area, and future changes in target concepts and commodities will no doubt attract further exploration. High-volatile bituminous coal is mined in the Buller Coalfield, mainly from the Brunner Coal Measures (Eocene). Estimates of recoverable resources indicate that this area is likely to produce coal well into the 21st century. Collingwood, Takaka, Nelson-Richmond, Baton, and Karamea coalfields have produced coal in the past but remaining resources are small. The Heaphy Coal Deposit has never been worked. The highest potential for commercial quantities of hydrocarbons within the Motueka sheet area is offshore in the Late Mesozoic-Cenozoic sequences west and north of Cape Farewell. Groundwater is utilised in the horticultural areas adjacent to Tasman Bay and to a lesser extent in the lower Takaka valley. Most groundwater comes from Late Quaternary sediments but, except near Motueka, the resource is fully committed. The deeper parts of the Moutere Gravel beneath the Moutere valley contain appreciable quantities of water. The gravel further east, beneath the water-poor Waimea plains, has yet to be tested. (auth)