A late glacial Antarctic climate teleconnection and variable Holocene seasonality at Lake Pupuke, Auckland, New Zealand

Research output: Contribution to journalArticle

Abstract

We present the first continuous paleolimnological reconstruction from the North Island of New Zealand (37A degrees S) that spans the last 48.2 cal kyr. A tephra- and radiocarbon-based chronology was developed to infer the timing of marked paleolimnological changes in Lake Pupuke, Auckland, New Zealand, identified using sedimentology, magnetic susceptibility, grain size and geochemistry (carbon, nitrogen and sulphur concentrations and fluxes, carbon and nitrogen stable isotopes). Variable erosional influx, biomass and benthic REDOX conditions are linked to changing effective precipitation and seasonality within three inferred broad intervals of climatic change: (1) the Last Glacial Coldest Phase (LGCP) of reduced effective precipitation and cooler temperatures, from 28.8 to 18.0 cal kyr BP, (2) the Last Glacial Interglacial Transition (LGIT) of increasing effective precipitation and warmer conditions, from 18.0 to 10.2 cal kyr BP, and (3) a Holocene interval of high effective precipitation, beginning with a warm period of limited seasonality from 10.2 cal kyr BP and followed by increasing seasonality from 7.6 cal kyr BP. The LGCP and LGIT also contain millennial-scale climate events, including the coldest inferred glacial conditions during the LGCP from 27.8 to 26.0 and 22.0-19.0 cal kyr BP, and a climate reversal in the LGIT associated with lower lake level, from 14.5 to 13.8 cal kyr BP, coeval with the Antarctic Cold Reversal. The onset of seasonal thermal stratification occurred at 5.7 cal kyr BP and was linked to natural eutrophication of Lake Pupuke, which produced enhanced organic sedimentation.

Details

Authors
  • Thomas Stephens
  • Daniel Atkin
  • Paul Augustinus
  • Philip Shane
  • Andrew Lorrey
  • Alayne Street-Perrott
  • Andreas Nilsson
  • Ian Snowball
Organisations
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Geology

Keywords

  • Climate and environmental change, Antarctic teleconnection, Seasonality, Elemental flux, Stable isotope, Erosion, Biological productivity, Mixing
Original languageEnglish
Pages (from-to)785-800
JournalJournal of Paleolimnology
Volume48
Issue number4
Publication statusPublished - 2012
Publication categoryResearch
Peer-reviewedYes