Cooling and changing seasonality in the Southern Alps, New Zealand during the Antarctic Cold Reversal

A comprehensively 14C AMS dated pollen and chironomid record from Boundary Stream Tarn provides the first chironomid-derived temperature reconstruction to quantify temperature change during Lateglacial times (17,500–10,000 cal yr BP) in the Southern Alps, New Zealand. The records indicate a ca 1000-...

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Bibliographic Details
Published in:Quaternary Science Reviews
Main Authors: Vandergoes, MJ, Dieffenbacher-Krall, AC, Newnham, RM, Denton, GH, Blaauw, Maarten
Format: Article in Journal/Newspaper
Language:English
Published: Uppsala universitet, Paleobiologi 2008
Subjects:
Geology
Geologi
Antarctic
New Zealand
The Antarctic
Antarc*
Antarctica
Online Access:http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-87622
https://doi.org/10.1016/j.quascirev.2007.11.015
Description
Summary:A comprehensively 14C AMS dated pollen and chironomid record from Boundary Stream Tarn provides the first chironomid-derived temperature reconstruction to quantify temperature change during Lateglacial times (17,500–10,000 cal yr BP) in the Southern Alps, New Zealand. The records indicate a ca 1000-year disruption to the Lateglacial warming trend and an overall cooling consistent with the Antarctic Cold Reversal (ACR). The main interval of chironomid-inferred summer temperature depression ( 2–3 °C) lasted about 700 years during the ACR. Following this cooling event, both proxies indicate a warming step to temperatures slightly cooler than present during the Younger Dryas chronozone (12,900–11,500 cal yr BP). These results highlight a direct linkage between Antarctica and mid-latitude terrestrial climate systems and the largely asynchronous nature of the interhemispheric climate system during the last glacial transition. The greater magnitude of temperature changes shown by the chironomid record is attributed to the response of the proxies to differences in seasonal climate with chironomids reflecting summer temperature and vegetation more strongly controlled by duration of winter or by minimum temperatures. These differences imply stronger seasonality at times during the Lateglacial, which may explain some of the variability between other paleoclimate records from New Zealand and have wider implications for understanding differences between proxy records for abrupt climate change.

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