ANÁLISIS DE ÍNDICES DE DESEMPEÑO DEL SERVIDOR BASE DE DATOS

We present 176_Hf/177_{Hf measurements and Nd and Pb isotope replicates on 25 lavas}

from Kaua‘i and 35 lavas from Ni‘ihau (Fig. 3.1, Supplementary Table 1 of Béguelin et al., 2017) previously described for major, trace elements and Sr–Nd–Pb isotopes (Dixon et al., 2008, Cousens and Clague, 2015). Twenty-two of these samples are submarine and were collected by the ROV Tiburon of the Monterey Bay Aquarium Research Institute (MBARI) dives T316–T324 in 2001. Cruise and sampling information can be found in Cousens and Clague (2015).

Of the Kaua‘i lavas, nine belong to the shield stage (tholeiites and picrites from the Nāpali, Hā‘upu, Olokele, and Makaweli Members, 5.8–4.3 Ma), four to the post-shield stage (alkali basalts, hawaiites and mugearites from the Olokele, Makaweli and Nāpali Members, 4.4–3.9 Ma), and 12 to the rejuvenated stage (alkali basalts, basanites, nephelinites and melilitites from the Kōloa Volcanics, 3.7–0.15 Ma) (Cousens and Clague, 2015).

Figure 3.1. Maps of sample locations. (a) Ka‘ula, Ni‘ihau and Kaua‘i islands. See Dixon et al. (2008) and Cousens and Clague (2015) for detailed maps of Ni‘ihau and Kaua‘i sampling locations. (b) Hawaiian archipelago with the locations of samples from the North Arch submarine volcanic field (samples described in Frey et al., 2000). Contour lines: −2000 m.

Of the Ni‘ihau lavas, eight belong to the shield stage (tholeiites from the Pānī‘au Basalt, 5.6–5.4 Ma), eight to the late-shield stage (transitional basalts from the Pānī‘au Basalt, 5.4–4.8 Ma), four to the post-shield stage (basanites from the Submarine Alkalic Suite that were not dated; note: we reclassify two of these samples as rejuvenated), and 15 to the rejuvenated stage (alkali basalts from the Ki‘eki‘e Basalt, 2.3–0.3 Ma) (Dixon et al., 2008, Cousens and Clague, 2015).

We also present Sr, Nd, Pb and Hf isotope data for 12 samples dredged from the submarine North Arch volcanic field (basanites and nephelinites, 1.15–0.5 Ma) by the R/V Farnella of USGS in 1988 (cruise F11-88HW, Clague et al., 1990). These samples are described for major and trace elements in Frey et al. (2000).

Isotope measurements were carried out at the Center for Elemental Mass Spectrometry, University of South Carolina. For the North Arch samples, 100–200 mg of rock powder or chips were leached for 30 min in cold 2N HCl before dissolution in a 3:1 mixture of Teflon-distilled HF and HNO3. For Kaua‘i and Ni‘ihau samples, 60 mg of rock

were dissolved for 176_Hf/177_{Hf determinations, 20 mg for} 143_Nd/144_{Nd replicates, and 200}

mg after cold leaching in 2N HCl for Pb isotope replicates. Strontium, Nd, Pb and Hf fractions were subsequently purified using standard chromatographic separation techniques for this lab (Mallick et al., 2015, Frisby et al., 2016, Béguelin et al., 2017). Hafnium, Nd, Pb and Sr isotope ratios were measured on a Thermo Scientific Neptune MC-ICP-MS. The data are reported in the Supplementary Table 1 of Béguelin et al. (2019), along with measurements of the BHVO-2 and AGV-1 USGS reference materials.

Measured 176_Hf/177_{Hf ratios were corrected from mass fractionation using} 179_Hf/177_{Hf = 0.7325 and monitored for accuracy by repeated measurements of the JMC-}

475 standard (Patchett and Tatsumoto, 1980), which averaged 176_Hf/177_{Hf = 0.282147 ±}

0.000008 (two standard deviations, n = 29); values are reported relative to 176_Hf/177_{Hf =}

0.282160. Full procedural blanks averaged 95 pg. Measured 143_Nd/144_{Nd ratios were}

corrected from mass fractionation using 146_Nd/144_{Nd = 0.7219 and monitored for accuracy}

by repeated measurements of the JNdi-1 standard (Tanaka et al., 2000), which averaged

143_Nd/144_{Nd = 0.512110 ± 0.000017 (two standard deviations n = 16); values are reported}

relative to 143_Nd/144_{Nd = 0.512115. Full procedural blanks averaged 6 pg. Hf and Nd}

isotope ratios are expressed by εHf and εNd using 176Hf/177HfCHUR = 0.282785 and 143_Nd/144_{NdCHUR = 0.512630 (Bouvier et al., 2008).}

Measured 87_Sr/86_{Sr ratios were corrected for mass fractionation using} 86_Sr/88_{Sr =}

0.1194. Repeated measurements of the NIST SRM987 standard (Ehrlich et al., 2001), averaged 87_Sr/86_{Sr = 0.710312 ± 0.000011 (two standard deviations, n = 7); values are}

reported relative to 87_Sr/86_{Sr = 0.710250. Full procedural blanks averaged 118 pg.}

Measured Pb isotope ratios were corrected for mass fractionation following the method of Todd et al. (2015), which uses the correlation between all measured Pb isotope ratios of the NBS981 standard and the measured 205_Tl/203_{Tl of the added Tl spike in a given}

analytical session to calculate a theoretical measured NBS981 value for each measured sample, and correct measurements to the accepted values of Galer and Abouchami (1998). Average corrected NBS981 values are therefore identical to accepted values, with an average precision (2 standard deviations) of 0.3‰ on 206_Pb/204_{Pb, 0.4‰ on} 207_Pb/204_{Pb, and}

0.5‰ on 208_Pb/204_{Pb for a single analytical session. Full procedural blanks averaged less}

Replicate 143_Nd/144_{Nd measurements on Kaua‘i and Ni‘ihau lavas reported in}

Cousens and Clague (2015) are reproduced within error, however the older Nd isotope data for Ni‘ihau rejuvenated lavas reported in Dixon et al. (2008) could not be replicated and are supplanted by new values reported here for these samples. Also, 42 Pb isotope replicates for Kaua‘i and Ni‘ihau lavas originally reported in Dixon et al. (2008) and Cousens and Clague (2015) based on the TIMS method, cannot be reproduced using the Tl spike method. The replicate data plot within the range of the older TIMS data in Pb isotope diagrams (Supplementary Fig. 1 of Béguelin et al., 2019), however showing a smaller

207_Pb/204_{Pb variance and plotting as linear trends instead of clusters, akin to similar datasets}

for rejuvenated lavas from the islands of O‘ahu and Ka‘ula (Fekiacova et al., 2007, Bizimis et al., 2013). The new data therefore supplant the prior data.