Table 1.
Bulk compositions of pre-experimental pseudo-ash samples measured with X-ray fluorescence.
| Bulk oxide abundance (wt %) | LW-NINW | LW-ONW | R-1 | K38-PC2 | SHV347-B | OBS1 | ECF2LAP* |
|---|---|---|---|---|---|---|---|
| Basic samples | Intermediate samples | Acidic samples | |||||
| SiO2 | 48.78 | 49.12 | 53.56 | 53.43 | 58.11 | 76.19 | 72.75 |
| TiO2 | 1.96 | 1.90 | 0.78 | 0.61 | 0.64 | 0.14 | 0.32 |
| Al2O3 | 17.13 | 17.14 | 17.98 | 19.39 | 18.21 | 12.71 | 14.19 |
| Fe2O3 | 11.29 | 11.36 | 9.21 | 8.79 | 7.34 | 1.32 | 2.10 |
| MnO | 0.18 | 0.18 | 0.16 | 0.23 | 0.19 | 0.05 | 0.05 |
| MgO | 5.90 | 5.73 | 6.06 | 4.37 | 2.95 | 0.15 | 0.68 |
| CaO | 8.27 | 8.46 | 7.80 | 9.74 | 7.70 | 0.44 | 1.66 |
| Na2O | 3.49 | 3.22 | 2.40 | 2.83 | 3.61 | 4.40 | 3.81 |
| K2O | 1.82 | 1.73 | 0.99 | 0.56 | 0.79 | 4.59 | 4.35 |
| P2O5 | 1.19 | 1.16 | 0.12 | 0.13 | 0.14 | 0.02 | 0.09 |
| Total | 100 | 100 | 99 | 100 | 100 | 100 | 100 |
| Rb/a | 0.45 | 0.44 | 0.37 | 0.36 | 0.29 | 0.12 | 0.14 |
Each value is an average of five individual measurements. Based upon these values, the two basic samples (LW-NINW and LW-ONW) are classified as trachybasalts, the three intermediate samples (R-1, K38-PC2, and SHV347-B) are considered basaltic andesites/andesites, and the acidic samples (OBS1 and ECF2LAP) are classified as rhyolites. Rb/a is the ratio of basic to acidic oxides and is calculated as Rb/a = (CaO + Fe2O3 + MgO + K2O + Na2O + MnO)/(SiO2 + Al2O3 + TiO2 + P2O5) following previous methods32. *Values for ECF2LAP are not those of the exact sample used in the experiments, but for a different pyroclast derived from the same eruptive sequence.