Analytical methods and reproducibility of reference material dates for (U–Th)/He thermochronology at the geochronology laboratory of the IGGCAS, China

Abstract

The (U–Th)/He dating technique has been widely used for several decades to constrain the timing of low-temperature geological processes. In this contribution, we describe the detailed procedures developed and the dating results of reference materials obtained for over a decade in a low-temperature thermochronological laboratory at the Institute of Geology and Geophysics, Chinese Academy of Sciences (IGGCAS), which allows (U–Th)/He ages to be obtained with an analytical uncertainty of 1–3%. The (U–Th)/He geochronological data of U- and Th-bearing minerals at the IGGCAS laboratory are obtained through a combination of crystal selection, helium extraction by laser heating and measurement by noble-gas quadrupole mass spectrometry (QMS), and U and Th measurement by isotope dilution using inductively coupled plasma-mass spectrometry (ICP-MS). More specifically, the (U–Th)/He geochronological data of widely used reference materials, such as Durango apatite and Fish Canyon Tuff (FCT) zircon and titanite, are reported, which are consistent with previously published results. Moreover, newly developed potential reference minerals such as MK-1 apatite, Penglai zircon (PL) and M6635 vesuvianite are reported with a considerable precision of 1–3% for the single crystal/fragment of uncorrected (U–Th)/He date.