Trace and Rare Earth Element geochemical data

Brief description

Trace and rare earth element geochemical data analysed from glass mounts from samples collected from Heard Island, Kerguelen Plateau. Samples were analysed at the University of Tasmania LA-ICPMS Facilities between 2014-2019. ICPMS trace elements analysis in CODES, School of Physical Sciences (Earth Sciences), University of Tasmania (modified after P.Robinson by E.Lounejeva, August 2017) Digestion 100.00 ± 0.05 mg of rock powder was dissolved in a mixture of inorganic acids (HF:H2SO4=3:3) at 180°C in closed PTFE vessels in Digestion Acid System (DAS, PicoTrace®). The mixture was then evaporated to dryness. Solid residuals were dissolved in HClO4, evaporated, re-dissolved in HNO3 and then diluted to 100.000 ± 0.050 ml. The resulting final solution contained the completely dissolved sample diluted 1000 times in a weak acid (2v/v% HNO3), 10 μg/ml of a mixture of Rh, In and Re as internal standard and traces of HF added to stabilize Ta and Nb. Digestion reagents blanks and international standards were processed along samples. All the solutions were then analysed by inductively coupled plasma mass spectrometry (ICP-MS) on an Agilent®-7700x instrument within 48 hours of dilution. Calibration of the instrument involved high purity standards solutions (CHOICE Analytical ®) for quantification and for estimation of isobaric interferences from Ba, Ce, Nd, Pr and Zr, all prepared in the same matrix. Multi-elemental calibration solutions were prepared at concentrations 5, 10 and 20 μg/ml. Data reduction and Quality control Mass-spectral data were collected as counts per second using Mass Hunter (Agilent ®) software and reduced through home-developed spread sheet (CODES, UTAS) using Excel Software (Microsoft Corporation ®). Reduction includes corrections by isobaric interferences, background and digestion procedure blank contribution, instrumental drift and dilution. Quantification includes a secondary correction by linear regression on three standard referenced materials (SRM), namely TASGRAN, TASBAS and AGV-1. The overall analytical uncertainty was estimated for each analysis (see report). In addition, the data quality, precision and accuracy, can be estimated on replicates for the analysed unknown samples and a very well-known SRM, basalt BCR-2, as it has a similar matrix to the analysed samples. Elements analysed Li, Be, Sc, Ti, V , Cr, Mn, Co, Ni, Cu, Zn, As, Rb, Sr, Y , Zr, Nb, Mo, Ag, Cd, Sn, Sb, Te, Cs, Ba, REE (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu), Hf, Ta, W , Tl, Pb, Bi, Th, U Reagents used: Seastar BASELINE high purite grade (Seastar Chemicals Inc, USA), Type-I Mili-Q ultra-pure water (Merk Millipore) and high purity standards (HPS) (CHOICE Analytical). Environment for Sample preparation: Clean lab class ISO5. References: Agilent http://www.agilent.com/about/companyinfo/ CHOICE Analytical http://choiceanalytical.com.au/standards-and-crms/high-purity-standards/ GEOREM http://georem.mpch-mainz.gwdg.de/sample_query_pref.asp. PicoTrace http://www.picotrace.de/products-das.html