The geological and depositional setting of the Brunner coal measures, New Zealand, and the influence of these factors on seam thickness and petrological characteristics of Brunner coals

The Brunner Coal Measures comprise up to 300 metres of sandstone, mudstone, coal and conglomerate at the base of an Eo-Oligocene transgressive sequence in North Westland. They generally contain one laterally extensive coal seam that is locally up to fifteen metres thick. Seam-splitting is generally simple but in places complex multiple splitting occurs and coal of mineable thickness may be absent. Regional differences in total thickness and local variations in seam thickness largely reflects variations in local rates of subsidence and syn-depositional faulting.