Synopsis
The research paper titled “A radiocarbon spike at 14 300 cal yr BP in subfossil trees provides the impulse response function of the global carbon cycle during the Late Glacial” presents new findings on radiocarbon ages measured on subfossil Scots Pines recovered in the Southern French Alps. The researchers analyzed about 400 new radiocarbon ages on 15 trees sampled at an annual resolution. The resulting radiocarbon record exhibits an abrupt spike occurring in a single year at 14 300–14 299 cal yr BP and a century-long event between 14 and 13.9 cal kyr BP.
The researchers compared the radiocarbon record with simulations of radiocarbon based on the 10Be record in Greenland ice used as an input of a carbon cycle model. The correspondence with 10Be anomalies allowed them to propose the 14.3 cal kyr BP event as a solar energetic particle event. The 14 cal kyr BP event, which lasted about a century, is most likely a common Maunder-type solar minimum linked to the modulation of galactic cosmic particles by the heliomagnetic field.
The researchers also discussed and speculated about the synchronicity and the possible causes of the 14 cal kyr BP event with the brief cold phase called Older Dryas, which separates the Bølling and Allerød millennium-long warm phases of the Late Glacial period.
The research contributes to the understanding of the global carbon cycle during the Late Glacial period and the role of solar energetic particles in radiocarbon production.
