GISP2 ice-core volcanic sulfate concentration and deposition between 2635 and 2638 m depth (c. 80 ka BP)

We present continuous records of 1 cm resolved sodium, sulfur, non-sea-salt sulfur, size-resolved insoluble particle concentrations and liquid conductivity using a Continuous Flow Analysis (CFA) system (McConnell et al., 2017) from the Greenland Ice Sheet Project Two (GISP2; 72.97°N, 38.80°W) ice core and estimated volcanic sulfate mass depositions for the depth interval 2635-2638 m (equivalent to an age of c. 80 ka BP on GICC05modelext (Seierstad et al., 2014) and 79.5 ka BP on AICC2012 (Veres et al., 2013). The reconstruction is based on sulfur measurements employing high-resolution continuous flow analysis coupled to inductively coupled plasma mass spectrometry performed at the Desert Research Institute (Reno, NV, USA) under (class 100) cleanroom conditions. Volcanic eruptions are detected when annual sulfur concentrations exceeded the background concentrations + 4 times the median of the absolute deviation. Background concentrations are estimated using a 101-point running median. Volcanic sulfate deposition rates are calculated by subtracting the background concentrations from total sulfate equivalent (i.e. sulfur x 3) concentrations using thinning corrected estimates of mean ice accumulation rates at the ice-core site.