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Luminescence chronology of loess-paleosol sequences from southern South Island, New Zealand
The loess-paleosol sequences in New Zealand are among the thickest in the southern hemisphere, and preserve an important terrestrial record of paleoclimatic changes. Unlike loess-paleosol sequences in North Island, most of those in South Island lack discrete chronostratigraphic marker ash beds, exce...
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Published in: | Quaternary science reviews 2002-09, Vol.21 (16), p.1899-1913 |
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Main Authors: | , , , |
Format: | Article |
Language: | English |
Citations: | Items that cite this one |
Online Access: | Get full text |
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Summary: | The loess-paleosol sequences in New Zealand are among the thickest in the southern hemisphere, and preserve an important terrestrial record of paleoclimatic changes. Unlike loess-paleosol sequences in North Island, most of those in South Island lack discrete chronostratigraphic marker ash beds, excepting perhaps the widespread ∼24
ka Kawakawa Tephra. Therefore, any specific correlation to marine isotope stage (MIS) proxy records or to loess-paleosol sequences in the northern hemisphere has been unknown. Hence, we applied luminescence sediment dating to four key loess-paleosol sequences from southern South Island.
Although these pioneering results suggest that further sampling and luminescence dating are needed, they do provide: (1) the first numeric age constraint (44±3
ka on overlying loess) for the end of deposition of the geomorphically and paleoclimatically important Edendale Terrace gravels; (2) the first numeric evidence that the youngest loess-paleosol unit (L1) at the near-coastal Romahapa and inland Stewarts Claim sites began to be preserved much earlier (at ∼60
ka) than at the inland Kingston Crossing site (∼35
ka); (3) the first direct evidence that the 6
m Romahapa sequence extends at least to ∼350
ka, the oldest yet TL-dated such sequence in South Island. Furthermore, the stratigraphically self-consistent (with one exception) luminescence ages between ∼60 and ∼350
ka conflict with a previous indirect chronostratigraphy inferred from trace concentrations of glass shards. This trace-shard chronology implies a major hiatus in loess-paleosol preservation (missing at least MIS 6–7) not recognized by luminescence dating. |
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ISSN: | 0277-3791 1873-457X |
DOI: | 10.1016/S0277-3791(02)00021-5 |