Determination of ²³⁰Th dating age of uranium-series standard samples by multiple collector inductively coupled plasma mass spectrometry

Five Quaternary standard samples were dated, and isotope ratios of U and Th contained in standard solutions were measured by Neptune Plus multiple collector inductively coupled plasma mass spectrometry (MC-ICP-MS). The results show that the ²³⁴U/²³⁸U atomic ratios of CRM 112A and Harwell Uraninite-1 (HU-1) are (52.860±0.042)×10^-6 (δ²³⁴U=(-38.36±0.77)‰, n=17) and (54.911±0.007)×10^-6 (δ²³⁴U=(-1.04±0.13)‰, n=27), respectively, which are in excellent agreement with the data previously reported by other laboratories within 2σ error; samples of 0.6 pg ²³⁰Th (NBS Th standard) give the precisions less than 3‰; the ages of five carbonate standards are (47 520±220) y, (86 880±340) y, (130 830±550) y, (129 380±480) y and (197 970±1 590) y for 76001, GBW04412, RKM-6, RKM-5 and RKM-4, respectively. These data are in accordance with the replicates measurements in the laboratories of Minnesota University and Xi'an Jiaotong University within uncertainties. All errors herein quote at the 2σ level, and all samples above are performed in the Uranium-series chronology laboratory of Institute of Geology and Geophysics, Chinese Academy of Sciences. This approach can be applied to dating various materials since late-middle Pleistocene, materials, such as speleothems, corals, deep-sea sulfides and so on.