Whole-rock analyses of core samples from the 1967, 1975, 1979 and 1981 drillings of Kilauea Iki lava lake, Hawaii

Abstract

All of the analyses presented here were obtained by classical gravimetric analysis in U.S. Geological Survey laboratories in Denver and Reston. The earliest analyses [job nos. 955{DCS) and PD99 in the tables] were done in Denver, following the procedures described in Peck (1964). All subsequent analyses were done in Reston, following the procedures outlined in Kirschenbaum (1983). These analyses include FeO, H2O ±, and CO2 determinations, made as described in the references cited. in addition to those components determined by standard gravimetric analysis, most of these analyses include determinations of Cr, Cl and F. Cr was originally analyzed using a colorimetric determination (E. Engleman and H. Kirschenbaum analyses, plus the J.W. Marinenko analyses in jobs BD02 and BD25). The method used was that of Maxwell (1968) and Sandell (1959). Subsequently (in the later J. W. Marinenko analyses), Cr was determined by flame AA, as described in Aruscavage and Crock (1987). Cl was analyzed colorimetrically in the Engleman and Kirschenbaum analyses, while F was analyzed by ion-specific electrode, as described in Jackson and others (1987). Later analyses (major elements by J. W. Marinenko) used the ion specific electrode method for both Cl (as described in Jackson and others, 1987) and F (as modified by Kirschembaum, 1988). In addition, all samples in job 955(DCS), originally done in Denver, were reanalyzed by H. Kirschenbaum for F and Cl using the ion chromatograph in Reston (under new job no. BJ25). Samples in several of the earlier jobs (nos. PE74, PH48, BA23, BA56 and BD02, comprising 80 samples) were analyzed for total sulfur, as described in Jackson and others (1987). However, as sulfur was always found to be below the limit of detection, this determination was not made for subsequent samples. Many analytical chemists of the U.S. Geological Survey have been involved in obtaining this data set. The bulk of the analyses were the work of coauthors H. Kirschenbaum and J. W. Marinenko, including many of the Cr, Cl and F analyses. Other analysts who performed gravimetric analyses include G. Riddle [job no. 955(DCS)], and E. Engleman (job no. PD99). Some of the minor and trace element work involved other members of the Branch of Analytical Chemistry: some of the Cr determinations were done by J.G. Crock, M. Doughten and W.M. d'Angelo, while C. Skeen and D. Kobilis helped with the Cl and F analyses.

Magnesium isotopic composition of the Earth and chondrites

“…This is consistent with studies of the Kilauea Iki lava lake that suggest basalt differentiation does not fractionate Mg isotopes (Teng et al, 2007). A similar conclusion is drawn when our findings are compared with studies of coexisting olivines and pyroxenes in peridotite xenoliths from global locations, which suggest that no measurable Mg isotope Helz et al (1994), Frey et al (1994), Norman and Garcia (1999) and measured for this study.…”

Tin isotopic fractionation during igneous differentiation and Earth’s mantle composition

“…Sample KI79-3-150.4, with ~14 wt. % MgO (d 122 Sn = 0.46 ± 0.07 ‰), is close to the parental magma composition (Helz et al, 1994). As olivine crystallises and accumulates at the bottom of the sequence, d 122 Sn is unchanged, because D Fe , Zn ol/melt ≈ 0 (Fig.…”

“…Olivine is the dominant crystallising phase until the MgO content falls to ~7.4 wt. % in the melt, as noted in Helz et al (1994), at which point the liquid reaches the cpx + plg + ol cotectic, as shown by a change in slope of REE abundances against MgO (O'Neill, 2016; see Supplementary Information). Ilmenite then crystallises at the expense of olivine below ≈5 wt.…”

“…The differentiation sequence samples form a sub-alkali series with MgO content ranging from 25.83-2.37 wt. % (Helz et al, 1994) (see Supplementary Information). The four spinifex-textured komatiites have 23.54 < MgO (wt.…”

“…Sulphides are present in evolved basalts as isocubanite and bornite (having exsolved from high temperature intermediate solid solution), however their low modal abundance (<0.01 %; Stone and Fleet, 1991) means they have a negligible effect on the Sn budget of the magma. Furthermore, by analogy with Fe isotopes (Wawryk and Foden, 2017), Cu-bearing sulphides Helz et al (1994). b Maximum of either 2 times the standard deviation on the sample measurement or BCR-2 external reproducibility.…”