Neodymium Clause Samples

Neodymium. Nd isotopic ratios were carried out by thermal ionization mass spectrometry (Isoprobe- T, GV Instrument) at the Laboratory of analytical development for isotopic and elementary analysis and by multicollector inductively coupled plasma mass spectrometry (Neptune Plus, Thermo ▇▇▇▇▇▇ Scientific) at the LSCE (Laboratoire des Sciences du Climat et de l’Environnement) laboratory. Nd was isolated from the bulk sample using two different methods. In the first one (for the samples analysed by ▇▇▇▇) the protocol followed the method already described by ▇▇▇ et al. (1994, 1997). The second one isolated the rare earth element using a Tru-Spec resin (▇▇▇▇▇▇▇▇▇▇ et al., 2009) followed by a high performance liquid chromatography using a ▇▇▇▇ SCX (Strong Cation Exchange) analytical column with 2-hydroxy-2-methylbutyric acid (HMBA, Sigma–▇▇▇▇▇▇▇) complexing agent (▇▇▇▇▇▇▇▇▇ et al., 2009, ▇▇▇▇▇▇▇▇▇ et al., 2011). For ▇▇▇▇ measurements, Nd was acquired in multistatic mode and using the total evaporation method (▇▇▇▇▇▇ et al., 1992). This method was adapted to allow measurements of low quantity of Nd, between 1 and 5ng (▇▇▇▇▇▇ et al., 2011). The average value for 143Nd/144Nd for the JNd-1 was found to be 0.51204 ± 0.00089 (n=20). For MC-ICP-MS measurements, the instrument was equipped with an Apex system to increase the sensibility at a value of 420V/ppm. Nd sample were analysed at concentration around 2 ng·g-1. Data are corrected from mass bias using JNdi-1 and standard bracketing method. Data were also corrected from an residual Sm contamination using the ratio 147Sm/149Sm=1.08680 ± 0.00016 (▇▇▇▇▇▇, 2005). εNd(0) was determined using the value (143Nd/144Nd)CHUR=0.512638.