F. Tera Rosalind Tuthill Helz R.J. Walker P.B. Tomascak 1999 <p><span>We report measurements of the isotopic composition of lithium in basalts using a multicollector magnetic sector plasma-source mass spectrometer (MC-ICP-MS). This is the first application of this analytical technique to Li isotope determination. External precision of multiple replicate and duplicate measurements for a variety of sample types averages ±1.1‰ (2σ population). The method allows for the rapid (∼8 min/sample) analysis of small samples (∼40 ng Li) relative to commonly used thermal ionization methods. The technique has been applied to a suite of samples from Kilauea Iki lava lake, Hawaii. The samples range from olivine-rich cumulitic lava to SiO</span>₂<span>− and K</span>₂<span>O-enriched differentiated liquids, and have δ</span>⁷<span>Li (per mil deviation of sample&nbsp;</span>⁷<span>Li/</span>⁶<span>Li relative to the L-SVEC standard) of +3.0 to +4.8. The data indicate a lack of per mil-level Li isotope fractionation as a result of crystal–liquid fractionation at temperatures greater than 1050°C. This conclusion has been tacitly assumed but never demonstrated, and is important to the interpretation of Li isotope results from such geochemically complex environments as island arcs.</span></p> application/pdf 10.1016/S0016-7037(98)00318-4 en Elsevier The absence of lithium isotope fractionation during basalt differentiation: New measurements by multicollector sector ICP-MS article