Supplementary Materials
Lithosphere vs. Asthenosphere Mantle Sources at Big Pine Volcanic Field
E. Gazel1,2*; T. Plank2; D.W. Forsyth3; C. Bendersky2; C. T. A. Lee4; E. H., Hauri5
1. Department of Geosciences, Virginia Tech
2. Lamont-Doherty Earth Observatory of Columbia University
3. Department of Geological Sciences, Brown University
4. Department of Earth Science, Rice University
5. Department of Terrestrial Magnetism, Carnegie Institution
*Corresponding author (E. Gazel): E-mail: egazel@vt.edu, Phone: +1-540-231-2296
1. Data and Analytical Methods
1.1 Major element data
Melt inclusions and olivine phenocrysts were analyzed for major elements
using the Cameca SX100 microprobe at the American Museum of Natural History
(Tables S1 and S2). Analytical conditions for major element analyses of hydrous
glasses and olivine phenocrysts used a 10-nA beam current (4-nA for Na) and a
15kV accelerating potential with 12 μm diameter beam. Count times on peak for
major elements were 30s and 15s for backgrounds. Na2O was counted for 2s on
peak and 20s on background, FeOT count times were 20s on peak and 15s for
background. Replicate analyses of Lau Basin back-arc glass standards FR:ND-70-01
and FR:ND-60-01 (in the same session as the Big Pine melt inclusion analyses)
yielded average relative standard deviations (standard deviation/average; RSD) of
less than 5% for major elements (excluding MnO and Na2O, at ~ 10%, and P 2O5 at
~30%). Whole rock trace element composition of the host tephras and related lavas
were collected at Washington State University by XRF standard procedures
(Johnson et al., 1999) and are reported in Table S1.
Pyroxene separates from mantle xenoliths hosted in the Oak Creek flow (Lee
et al., 2005) were analyzed for major elements, Ni and Cr compositions at the AMNH
following the analytical conditions described above (Table S3). Replicate analyses
(n=10) of the Cr-Augite standard (USNM 164905; Jarosewich et al., 1987) yielded an
average RSD of less than 1.5% for major elements and Cr (excluding MnO at ~ 20%,
Na2O at at ~ 5% and Ni at ~ 30%,).
1.2. Trace elements
Trace element concentrations in melt inclusions and olivine (Tables S4 and S5)
were determined at LDEO by laser-ablation inductively coupled plasma mass
spectrometry (LA-ICP-MS). The analyses were performed with an ESI/New Wave
UP-193 Excimer laser ablation system coupled to a VG PQ ExCell quadrupole ICPMS. Samples were ablated in He at a flow rate of 1.5 L/min. The laser was operated
in spot-drill mode at 10 Hz, at 70% (irradiance of ~1.96 - 2.20 Gw/cm2 and fluence
of ~ 9.45 - 11.10 J/cm2). The laser spot sizes ranged from 40-50 µm (only melt
inclusions >50 µm were analyzed for trace element data) . Data were collected for
120s, including 60s of background. Dwell times for most elements were 10 ms,
except for the rare earth elements Hf, Pb, Th, and U, where dwell times were
increased to 50 ms. Laser data were acquired in time-resolved mode. Melt inclusion
data were calibrated against USGS standard glasses BHVO-2g, BCR-2g, and BIR-1g,
using
47Ti
as an internal standard and the standard values given in Kelley et al.
(2003). Olivines were calibrated against BIR-1g and San Carlos olivine (USNM
111312/44; Jarosewich et al., 1980) using 26Mg as an internal standard. The average
precision for three replicate analyses of BIR-1g (analyzed as an unknown with the
melt inclusions) was <5% RSD for most elements, except Pb, Th and U of ~10% RSD.
The whole rock trace element composition of the host tephras were collected at
LDEO with the VG PQ ExCell quadrupole ICP-MS using the sample preparation and
protocols detailed in Kelley et al. (2003). The results are in Table S4; the average
RSD for three replicate analyses was <3% for all elements with the exception of Rb
(<4%).
1.3. Volatiles
The concentrations of volatile species (H2O, CO2, Cl, F, and S) in melt
inclusions were obtained using the Cameca IMS 6f ion probe (SIMS) at the
Department of Terrestrial Magnetism of the Carnegie Institute of Washington (DTMCarnegie) following the procedures described by Hauri (2002) using a basaltic glass
calibration curve measuring H2O as 16O1H and CO2 as 12C. Supplementary Materials
Table X provides the concentrations of the glass standards used in the calibration
for the June 2009 session. A primary beam (5-10 nA) accelerated to 10 kV was used
to create a 20-40 μm spot size. Precision is assessed from replicate analyses of Lau
Basin glasses FR:ND-70-01 and FR:ND-60-01: 2-3% RSD for H2O, CO2, S, F and 5%
for Cl (Table S1).
Pyroxene separates from mantle xenoliths from the Oak Creek lava flow (Lee,
2005) were also analyzed at DTM-Carnegie for volatiles using the Cameca 6f ion
microprobe (Table S6). The ratios
16OH/30Si, 19F/30Si
and
31P/30Si
were monitored,
and concentrations were obtained following the procedures in Wade et al. (2008),
except separate calibrations were used for cpx and opx H2O. The cpx H2O calibration
was based on PMR-53, ROM271-10, -16, -21 (values in Aubaud et al., 2007), while
the opx H2O calibration was based on ROM273, KBH-1 (Aubaud et al., 2007 values)
and A288 (44 ppm H2O).
F and P concentrations were calibrated from glass
standards. The average RSD on 3 replicate analyses of ROM271-21 cpx was ~2% for
H2O and F, and ~0.2% for P.
2. References
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