Holocene ash fall from both local and distal volcanoes has affected Auckland more frequently than previously documented, with a possible average frequency of at least once every 424 years.
A study involving experts from New Zealand and Britain analysed and correlated microscopic pieces of volcanic ash known as ‘cryptotephra’ that had been preserved in Lake Pupuke/Pupuke Moana.
The work also highlights the importance of identifying the extent of the deposit reworking to establish the veracity of the cryptotephra record.
Geochemical fingerprinting, stratigraphic correlation, 14C ages, X-ray fluorescence and magnetic susceptibility core scanning have all been utilised to filter reworked tephra and establish a new Holocene chronological framework for the Lake Pupuke region.
