A high-resolution record of atmospheric 14C based on Hulu Cave speleothem H82

John Southon, Alexandra L. Noronha, Hai Cheng, R. Lawrence Edwards, Yongjin Wang

Research output: Contribution to journalArticlepeer-review

107 Scopus citations

Abstract

The development of a calibration of atmospheric radiocarbon ({increment} 14C) is a significant scientific goal because it provides the means to link the numerous 14C dated paleoclimate records to a common timescale with absolutely dated records, and thereby improve our understanding the relationships between the carbon cycle and climate change. Currently, few calibration datasets that directly sample the atmospheric 14C reservoir are available beyond the end of the dendro-dated Holocene tree ring record at 12.6kyr BP (Before 1950 AD). In the absence of suitable true atmospheric records, 14C calibrations beyond this age limit are based largely on marine data, that are complicated by the marine reservoir effect, which may have varied over the glacial cycle. In this paper, we present a high-resolution record of U-Th series and 14C measurements from Hulu Cave speleothem H82, spanning 10.6-26.8kyr BP. Corrections for detrital 230Th are negligible, and the contribution of 14C-free geologic carbon to the speleothem calcite is small (5-6%) and is stable across major climate shifts. The time series provides a 16kyr record of atmospheric {increment} 14C as well as an updated age model for the existing Hulu Cave δ 18O record. The 14C data are in good overall agreement with existing marine and terrestrial 14C records, but comparisons with the Cariaco Basin marine {increment} 14C record through the deglacial interval reveal that the Cariaco reservoir age appears to have varied during parts of the Younger Dryas and Heinrich Stadial 1 cold events. This highlights the importance of developing extended high-resolution marine and terrestrial 14C records as a means of detecting changes in ocean circulation over the glacial cycle.

Original languageEnglish (US)
Pages (from-to)32-41
Number of pages10
JournalQuaternary Science Reviews
Volume33
DOIs
StatePublished - Feb 6 2012

Keywords

  • Climate change
  • Hulu Cave
  • Radiocarbon calibration
  • Speleothems
  • U-Th

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