Stratigraphy, age and correlation of middle Pleistocene silicic tephras in the Auckland region, New Zealand: A prolific distal record of Taupo Volcanic Zone volcanism

摘要: Abstract Coastal sections in the Auckland region reveal highly carbonaceous and/or weathered clay‐dominated cover‐bed successions with numerous discrete distal volcanic ash (tephra) layers, fluvially reworked siliciclastic (tephric) deposits, and two widely distributed pyroclastic density current (PDC) deposits generated from explosive silicic volcanism within Taupo Volcanic Zone (TVZ). The younger of PDC (informally named Waiuku tephra) is glass‐isothermal plateau fission‐track (ITPFT) dated at 1.00 ± 0.03 Ma occurs a normal polarity interval interpreted as Jaramillo Subchron. tephra correlated Unit E sourced Mangakino Centre TVZ. can be subdivided into distinctive units enabling unequivocal field correlation: lower stratified unit (dominantly surge fall component) an upper massive to weakly (pyroclastic flow). At many sites south Auckland, retains basal...