Volcanic geology of the Taupo Basin

Abstract

The Taupo Basin is situated around Lake Taupo which included the Lake Taupo Volcanic Centre and the northern part of the Tongariro Volcanic Centre. Four main rocks types from the basin are described; rhyolites and dacites from the Lake Taupo Volcanic Centre; andesites from the Tongariro Volcanic Centre and basic andesites from both centres. Rhyolite domes and flows and andesite cones and flows are described. The interpretations of the internal structure and manner of growths of rhyolite and dacite domes are discussed with the aid of field evidence and comparision to the other known domes. The petrographical, mineralogical and where the analyses are available, the petrochemical studies were carried out. Eight new achemical analyses and four partial Electron Micro Probe analyses are given. Diagrams showing the relationships of these rocks are also illustrated. The petrogenesis, relationships and correlation between subdivisions of rhyolites, dacites and andesites are also discussed.