Melting processes in small basaltic systems : the Auckland Volcanic Field, New Zealand

Abstract

Geochemical analyses of melts erupted in small basaltic volcanic fields have the power to reveal particulars of their magmatic system from the inception of melting, to the processes that affect magmas on their ascent. The Auckland Volcanic Field (AVF) of northern New Zealand is a Quaternary intraplate basaltic volcanic field of c. 50 eruptive centres located over an area c. 360km2. The field has been extremely well-sampled over the past few decades thus providing an excellent basis from which to study the inner workings of a small volume monogenetic system. New analyses of rocks have been added to the existing geochemical dataset of the AVF, including Sr-Nd-Pb isotopes and a subset of U-Th-Ra isotopes. In addition to a whole-field study, two case studies of well-exposed volcanic centres in the AVF are presented: Rangitoto and Motukorea.