Stratigraphic nomenclature for the cretaceous-lower Quaternary rocks of Buller and North Westland, West Coast, South Island, New Zealand

Abstract

In forthcoming geological maps of Buller and North Westland, the Cretaceous to lower Quaternary rocks are divided into formations of varying lateral extent. New formations are listed in the Appendix. The following six groups are used to divide the sequence into major lithological units of regional extent: Old Man (youngest), Blue Bottom, Nile, Rapahoe, Mawheranui, and Pororari (oldest) Groups. Within the Inangahua and Grey valleys the Blue Bottom Group grades laterally into nonmarine sediments, mainly coal measures, which constitute the Rotokohu Coal Measures, an independent formation not included in any of the above groups.