Sample collection
The bulk of the dripwater data presented here is published, and full methods for sample collection and analyses can be found in the original publication (Treble et al. , 2016). Additional bulk dripwater samples were collected following that same method. Aliquots for SO4 dual isotope analyses of dripwaters were taken from those bulk samples. Bulk monthly rainfall samples were collected from April 2017 to January 2018 using a rain gauge. Both rain and dripwater samples were filtered using mixed cellulose 0.45 μm membrane filters and refrigerated at 5°C prior to analyses.
Soil samples were collected from the O and A horizons at 4 m intervals along a 20 m transect. Additional vertical samples were taken at 0.4 m and 1.4 m depth at one site. Soil samples were dried at 60 °C for 48 hours and sieved (2 mm) to remove the coarse fraction, roots, and other organic debris. O horizon samples were further separated into the > 0.5 mm and < 0.5 mm fractions. All soil samples were finely crushed using a ring grinder.
Three bedrock samples were collected for SO4 dual isotopic analyses.
Representative vegetation samples were collected from above Golgotha Cave (minimum three leaves and attached stems, with three replicates for each species). Samples were dried at 60°C for 48 hours and finely ground with a ball grinder. Where possible, leaves were separated from twigs and seeds for 34S analyses.
Speleothem GL-S4 was collected from Golgotha Cave in 2013. The sample is comprised of white porous calcite and has been dated with annual lamina counting via XFM mapping of Sr concentrations (unpublished data).