characteristics of the R1 and R2 compositional endmembers after Deering et al. (2008) and Deering et al. (2010). Domes were classified first by their petrographic characteristics (if this data was available), and then by whether they fulfilled the majority of the chemical characteristics. Domes that did not clearly fall into either R1 or R2 were classified as R1 + 2
| Criteria . | R1 . | R2 . | |
|---|---|---|---|
| Petrographic characteristics | Ferromagnesian mineral phases | amphibole ± biotite | orthopyroxene |
| Phenocryst content | Crystal-rich (10–45%) | Crystal-poor (<10%) | |
| Chemical characteristics (whole-rock) | FeOT wt %/MgO wt %: | Low (<11.4) | High (>11.4) |
| Sr (ppm): | High (>103 ppm) | Low (<103 ppm) | |
| Y (ppm): | Low (<27.4 ppm) | High (>27.4 ppm) | |
| Zr (ppm): | Low (<188 ppm) | High (>188 ppm) | |
| Criteria . | R1 . | R2 . | |
|---|---|---|---|
| Petrographic characteristics | Ferromagnesian mineral phases | amphibole ± biotite | orthopyroxene |
| Phenocryst content | Crystal-rich (10–45%) | Crystal-poor (<10%) | |
| Chemical characteristics (whole-rock) | FeOT wt %/MgO wt %: | Low (<11.4) | High (>11.4) |
| Sr (ppm): | High (>103 ppm) | Low (<103 ppm) | |
| Y (ppm): | Low (<27.4 ppm) | High (>27.4 ppm) | |
| Zr (ppm): | Low (<188 ppm) | High (>188 ppm) | |
characteristics of the R1 and R2 compositional endmembers after Deering et al. (2008) and Deering et al. (2010). Domes were classified first by their petrographic characteristics (if this data was available), and then by whether they fulfilled the majority of the chemical characteristics. Domes that did not clearly fall into either R1 or R2 were classified as R1 + 2
| Criteria . | R1 . | R2 . | |
|---|---|---|---|
| Petrographic characteristics | Ferromagnesian mineral phases | amphibole ± biotite | orthopyroxene |
| Phenocryst content | Crystal-rich (10–45%) | Crystal-poor (<10%) | |
| Chemical characteristics (whole-rock) | FeOT wt %/MgO wt %: | Low (<11.4) | High (>11.4) |
| Sr (ppm): | High (>103 ppm) | Low (<103 ppm) | |
| Y (ppm): | Low (<27.4 ppm) | High (>27.4 ppm) | |
| Zr (ppm): | Low (<188 ppm) | High (>188 ppm) | |
| Criteria . | R1 . | R2 . | |
|---|---|---|---|
| Petrographic characteristics | Ferromagnesian mineral phases | amphibole ± biotite | orthopyroxene |
| Phenocryst content | Crystal-rich (10–45%) | Crystal-poor (<10%) | |
| Chemical characteristics (whole-rock) | FeOT wt %/MgO wt %: | Low (<11.4) | High (>11.4) |
| Sr (ppm): | High (>103 ppm) | Low (<103 ppm) | |
| Y (ppm): | Low (<27.4 ppm) | High (>27.4 ppm) | |
| Zr (ppm): | Low (<188 ppm) | High (>188 ppm) | |
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