Tephrochronostratigraphy in marine and terrestrial sediments of New Zealand: Benchmark for Miocene to Quaternary explosive volcanism
ACRONYM
Neuseeland Tephras
Title
Tephrochronostratigraphy in marine and terrestrial sediments of New Zealand: Benchmark for Miocene to Quaternary explosive volcanism
General information
During IODP Expeditions 372 and 375 the overarching aim was to assess the causes and impacts of slow slip earthquakes as well as to investigate large submarine slides associated with gashydrates offshore North Island, New Zealand. Sediments have been drilled and sampled down to the Cretaceous including intercalated tephra layers from the Miocene to Holocene. The drill sites are located in the Pacific, ~250 km downwind of the Taupo volcanic Zone (TVZ), one of largest and most frequently active silicic centers on earth, and also close to the Coromandel volcanic zone (CVZ) a sparsely investigated Neogene volcanic arc. The tephra inventories of these intermediate distant sites provide the missing link between the proximal (<~100 km) terrestrial and very distal (~1000 km) ODP sites to establish a nearly complete eruptive history from the early Miocene to recent for New Zealand´s explosive volcanism.This project focuses therefore on the volcanic products from highly explosive eruptions from New Zealand during the Neogene and Quaternary. Tephra deposits from Exp. 372&375 complemented by tephras found on land and in older and more distal ODP drill cores provide the unique opportunity to investigate and compare the history of highly explosive volcanic activity of both arc systems (CVZ and TVZ), and their signals in marine sediments over a time span of about at least 12 Myrs. Geochemical, petrological and volcanological approaches for tephra and sediment characterization will be used to quantitatively and qualitatively decrypt their provenance and the eruption succession even for smaller eruptions potentially available as cryptotephras. Especially the crucial gap in trace elements, in both, terrestrial and former marine samples, will be filled. Additionally, we will perform absolute age dating to improve and confirm the existing age models. Robust age models are needed to study the temporal and spatial changes in eruption processes, magnitudes and frequencies of large volcanic eruptions from both, the TVZ and CVZ.Finally the herewith-established compositional data and eruptive time series will serve as base to address questions regarding recurrence rates and cyclicities in both systems, covering the first time also a Neogene eruption time series. It will also facilitate the temporal and quantitative characterization of the sediment composition at the slope and at the incoming plate in relation to the volcaniclastic input and answer the question how this may influence the mechanical, frictional, and hydrogeological properties of the sediments. Additionally the data provide a tool to backtrack displaced sediment blocks of the Hikurangi margin on the base of sediment geochemistry and tephra layers.
Start
October, 2019
End
September, 2022
Funding (total)
217000
Funding (GEOMAR)
-
Funding body / Programme
-
DFG
/
Coordination
Helmholtz-Zentrum für Ozeanforschung Kiel (GEOMAR), Germany
Contact
Partners
University of Wellington, New Zealand
