Atmospheric <sup>14</sup>C/<sup>12</sup>C changes during the last glacial period from Hulu Cave.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 30545886.
- Also identified by DOI 10.1126/science.aau0747.
- No licence information is recorded for this record.
- Because redistribution is not established, this page shows the abstract only. Follow the links below for the full text.
Abstract
Paired measurements of <sup>14</sup>C/<sup>12</sup>C and <sup>230</sup>Th ages from two Hulu Cave stalagmites complete a precise record of atmospheric <sup>14</sup>C covering the full range of the <sup>14</sup>C dating method (~54,000 years). Over the last glacial period, atmospheric <sup>14</sup>C/<sup>12</sup>C ranges from values similar to modern values to values 1.70 times higher (42,000 to 39,000 years ago). The latter correspond to <sup>14</sup>C ages 5200 years less than calibrated ages and correlate with the Laschamp geomagnetic excursion followed by Heinrich Stadial 4. Millennial-scale variations are largely attributable to Earth's magnetic field changes and in part to climate-related changes in the oceanic carbon cycle. A progressive shift to lower <sup>14</sup>C/<sup>12</sup>C values between 25,000 and 11,000 years ago is likely related, in part, to progressively increasing ocean ventilation rates.