Iron isotope of the mineral separates from Damiao titanomagnetite deposit, China

The dataset presented is iron isotope of the mineral separates from Damiao titanomagnetite deposit, China. The samples were crushed to 80 – 100 mush using corundum jaw crusher to prevent Fe contamination. The disaggregated samples were introduced to a magnetic separator to divide magnetite from non-magnetic minerals (ilmenite and pyrite). Individual mineral phases were handpicked carefully under binocular microscope after the rinsing the magnetic separates in Milli-Q water.The mineral separates were dissolved in individual Teflon Parr bombs using a combination of ultra-pure 3:1:1 HNO3-HCl-HF on a hotplate. Once fully digested, samples were dried and redissolved in 9N HCl. Prior to iron chemical purification via ion exchange method, sample aliquots were analyzed on ICP-OES for major element concentrations. Then samples were loaded onto 1ml anion exchange resin (Bio-Rad AG MP-1M 200-400 mesh) preconditioned with 9N HCl. Interfering matrix elements including Cr and Ni were rinsed using 5ml 9N HCl. The columns were then washed with 5ml 6N HCl to remove Cu and possible residual Cr and Ni. Fe was collected using 2ml 1N HCl. The purified Fe aliquots were spiked with a GSB Ni standard solution (an ultrapure single element standard solution from the China Iron and Steel Research Institute) and diluted to match the standard Fe concentrations (~10 ppm Fe and ~14 ppm Ni). Prior to the Fe isotope analyses, the sample aliquots were analyzed on an Agilent 7500 ICP-MS to make sure all the Cr isotopes had been eluted, with results given in Table DR1.Fe isotope compositions were measured on a Nu-II MC-ICPMS with wet nebulization operating in medium-resolution mode (M/ΔM>8000) in order to partially resolve argides polyatomic interferences on iron masses. Backgrounds were measured and subtracted using electrostatic analyzer (ESA) deflection. Standard and sample solutions were introduced in 0.1N HCl medium in free-aspiration mode via a 100μm/min PFA nebulizer into a quartz dual cyclonic spray chamber. A 600s washout in Milli-Q water was conducted during each measurement. Individual measurement contained 30 blocks with 8s integration time. The Mass bias fractionation during analysis was corrected using Ni-doping method by 60Ni/58Ni with the 58Fe interference on 58Ni corrected based on 56Fe. Each individual sample was analyzed four times between individual GSB Fe (a substitution of IRMM-014) standard analyses. The GSB Fe standard has been reported relative to IRMM-014 (δ56FeIRMM-014 = δ56FeGSB + 0.729, δ57FeIRMM-014 = δ57FeGSB + 1.073; He et al., 2015).