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| Titel |
Multiproxy Paleoenvironmental Records Spanning the INTIMATE Timescale from Auckland Maar Lakes, New Zealand |
| VerfasserIn |
Paul Augustinus, Donna D'Costa, Tom Stephens, Daniel Atkin, Phil Shane, Ursula Cochran, Ian Snowball, Andreas Nilsson, Alayne Street-Perrott, Sarah Davies |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250043892
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| Zusammenfassung |
| High-resolution Late Quaternary paleoclimate archives are preserved in the lake sediment
records contained in several maar craters from the Auckland region in northern New Zealand.
Tephrochronology, AMS 14C and Ar/Ar -based chronostratigraphies were developed with
several lakes containing laminated sediment records spanning much of the last glacial cycle.
A multi-proxy approach was taken to construct a reliable record of local and regional
paleoenvironments including: pollen and diatom paleoecology, environmental magnetism,
grain size, XRF geochemistry, TOC, TN, TS, organic matter δ13C, δ15N and δD, as well as
δ18O in biogenic silica.
Pollen and diatom analysis of records spanning the last ca 60 ka show marked vegetation
changes that reflect orbital forcing, although diatoms suggest significant hydrological
changes that are not reflected in the pollen. Reduction of forest with expansion of grass and
shrublands at the start of the LGM (29 ka BP), is accompanied by cool, dry and windy
conditions, although the situation is complex with multiple brief warmer phases punctuating
the LGM. Post-glacial warming commenced ca 17.9 ka BP and is reflected in several proxies,
although the pollen record does not display the marked changes displayed in many of the
other proxies during the LGIT and Holocene. Some of the inferred environmental
changes are similar to the nature and timing of short-duration events during the last
glacial cycle from the North Atlantic region, although others appear to reflect a
southern polar forcing. The multi-proxy approach used has produced one of the most
complete, well-dated and high-resolution paleoenvironmental records spanning the
INTIMATE timescale from the mid-latitude Southern Hemisphere with implications for
the nature, timing and forcings of climate change in the Southwest Pacific region. |
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