An independently dated 2000-yr volcanic record from Law Dome, East Antarctica, including a new perspective on the dating of the 1450s CE eruption of Kuwae, Vanuatu

Abstract

Volcanic eruptions are an important cause of natural climate variability. In order to improve the accuracy of climate models, precise dating and magnitude of the climatic effects of past volcanism are necessary. Here we present a 2000-yr record of Southern Hemisphere volcanism recorded in ice cores from the high accumulation Law Dome site, East Antarctica. The ice cores were analysed for a suite of chemistry signals and are independently dated via annual layer counting, with 11 ambiguous years at 23 BCE, which has presently the lowest error of all published long Antarctic ice cores. Independently dated records are important to avoid circular dating where volcanic signatures are assigned a date from some external information rather than using the date it is found in the ice core. Forty-five volcanic events have been identified using the sulphate chemistry of the Law Dome record. The low dating error and comparison with the NGRIP (North Greenland Ice Core Project) volcanic records (on the GICC05 timescale) suggest Law Dome is the most accurately dated Antarctic volcanic dataset, which will improve the dating of individual volcanic events and potentially allow better correlation between ice core records, leading to improvements in global volcanic forcing datasets. One of the most important volcanic events of the last two millennia is the large 1450s CE event, usually assigned to the eruption of Kuwae, Vanuatu. In this study, we review the evidence surrounding the presently accepted date for this event, and make the case that two separate eruptions have caused confusion in the assignment of this event. Volcanic sulphate deposition estimates are important for modelling the climatic response to eruptions. The largest volcanic sulphate events in our record are dated at 1458 CE (Kuwae?, Vanuatu), 1257 and 422 CE (unidentified)

A glaciochemical study of the 120 m ice core from Mill Island, East Antarctica

“…The layer counting method using this multi-proxy approach was subsequently confirmed by the non-sea-salt sulfate (nssSO 2− 4 ) record, which matches the timing of volcanic eruptions (Pinatubo (1991), El Chichón (1982, and Agung (1963)) at LD (Plummer et al, 2012) and at other ice core sites (Cole-Dai et al, 1997, 2000. Figure 2 is attributed to calibration problems.…”

“…MI0910 and MIp0910 were dated by counting annual layers using H 2 O 2 , water isotopes (δ 18 O, δD), and D-ex according to the methods presented in (Plummer et al, 2012). The layer counting method using this multi-proxy approach was subsequently confirmed by the non-sea-salt sulfate (nssSO 2− 4 ) record, which matches the timing of volcanic eruptions (Pinatubo (1991), El Chichón (1982, and Agung (1963)) at LD (Plummer et al, 2012) and at other ice core sites (Cole-Dai et al, 1997, 2000.…”

A revised 1000 year atmospheric δ13C‐CO2 record from Law Dome and South Pole, Antarctica

“…The previously used DSS ice core age scale (LD1) [van Ommen et al, 2004] has been recently updated [Plummer et al, 2012] and shows a difference of less than 2 years from LD1 back to year 1000 A.D. The model estimated gas-age/ice-age difference for DSS is 54.8 years for our best case, with a range of 52.7-59.3 years from an ensemble of model parameters.…”

Climatic and societal impacts of a volcanic double event at the dawn of the Middle Ages

“…Available total sulfate flux (kg/km 2 ) derived for the 536 and 540 events from Antarctic and Greenland ice cores (Traufetter et al 2004;Larsen et al 2008;Plummer et al 2012;Sigl et al 2013) are listed in Table S1. To account for potential sampling bias from the small number of available ice cores available for this time period, and the spatial variability of sulfate deposition to the surface (e.g., Sigl et al 2014), Antarctic and Greenland averages are corrected using scaling factors derived from MAECHAM5-HAM simulations (Supplementary Methods, (Niemeier et al 2009;Toohey et al 2011;Toohey et al 2013)).…”