Bidgood et al., 2026 - Hydrothermal Kyanite - Supporting Information 1: LAICPMS U-Pb Monazite
Description
LA-ICP-MS U-Pb data for Monazite sample KVOD14-266.6 (Menda, DRC).
Files
Steps to reproduce
Monazite from 3 samples were imaged in situ via backscattered electron (BSE) imaging using a Tescan TIGER MIRA3 FEG-SEM coupled to two Oxford Instruments X-Max 150 mm2¬ EDS detectors using an accelerating voltage of 20 kV. LA-ICP-MS U-Pb monazite data were acquired using a Photon Machines Iridia 193 nm ArF excimer laser-ablation system with a Cobalt two-volume ablation cell coupled to an Agilent 7900 ICP-MS at the Department of Geology, Trinity College Dublin. The instrument was tuned using NIST612 standard glass to yield Th/U ratios of unity and low oxide production rates (ThO+/Th+ typically <0.15%). A quantity of 0.4 l min-1 He carrier gas was fed into the laser cell, and the aerosol was subsequently mixed with 0.6 l min-1 Ar make-up gas and 11 ml min-1 N2. Data reduction of the raw U-Pb isotope data was performed through the “VizualAge” data reduction scheme73 in the IOLITE 3 package74. Sample-standard bracketing was applied after the correction of downhole fractionation to account for long-term drift in isotopic or elemental ratios by normalizing all ratios to those of the U-Pb reference standards. A repetition rate of 11 Hz and a circular spot of 20 μm were employed. Twenty nine isotopes (27Al, 29Si, 31P, 44Ca, 55Mn, 88Sr, 89Y, 139La, 140Ce, 141Pr, 146Nd, 147Sm, 153Eu, 157Gd, 159Tb, 163Dy, 165Ho, 166Er, 169Tm, 172Yb, 175Lu, 202Hg, 204Pb, 206Pb, 207Pb, 208Pb, 232Th, 235U and 238U were acquired during each analysis, which comprised 27.3 s of ablation (300 shots) and 8 s washout, the latter portions of which were used for the baseline measurement. Manangotry monazite (207Pb/235U TIMS age of 554.2 ± 0.7175) was used as the primary U-Pb age calibration standard. The secondary age reference material Moacir (Moacyr) monazite (207Pb/235U TIMS age of 506.7 ± 0.876 and 504.3 ± 0.277) yielded a LA-ICP-MS weighted average 207Pb/235U age of 510.5 ± 2.6 (MSWD = 0.92, n =41). Age data were plotted in IsoplotR78.
Institutions
- Trinity CollegeMadrid, San Sebastian de los Reyes
- Carnegie Institution for ScienceDC, Washington
Categories
Funders
- Science Foundation IrelandIrelandGrant ID: 16/RP/3849 and 13/RC/2092_P2