Abstract. The South Pole Ice Core (SPICEcore) was drilled in 2014–2016 to provide a
detailed multi-proxy archive of paleoclimate conditions in East Antarctica
during the Holocene and late Pleistocene. Interpretation of these records
requires an accurate depth–age relationship. Here, we present the SPICEcore (SP19) timescale for the age of the ice of SPICEcore. SP19 is synchronized to the
WD2014 chronology from the West Antarctic Ice Sheet Divide (WAIS Divide) ice
core using stratigraphic matching of 251 volcanic events. These events
indicate an age of 54 302±519 BP (years before 1950) at the
bottom of SPICEcore. Annual layers identified in sodium and magnesium ions
to 11 341 BP were used to interpolate between stratigraphic volcanic tie
points, yielding an annually resolved chronology through the Holocene.
Estimated timescale uncertainty during the Holocene is less than 18 years
relative to WD2014, with the exception of the interval between 1800 to 3100
BP when uncertainty estimates reach ±25 years due to widely spaced
volcanic tie points. Prior to the Holocene, uncertainties remain within 124 years relative to WD2014. Results show an average Holocene accumulation rate
of 7.4 cm yr−1 (water equivalent). The time variability of accumulation rate
is consistent with expectations for steady-state ice flow through the modern
spatial pattern of accumulation rate. Time variations in nitrate
concentration, nitrate seasonal amplitude and δ15N of N2 in turn are as expected for the accumulation rate variations. The highly
variable yet well-constrained Holocene accumulation history at the site can
help improve scientific understanding of deposition-sensitive climate
proxies such as δ15N of N2 and photolyzed chemical
compounds.
