Development of CA-ID-TIMS zircon U–Pb dating technique at Guangzhou Institute of Geochemistry, Chinese Academy of Sciences

Abstract

U–Pb geochronology using isotope dilution-thermal ionization mass spectrometry (ID-TIMS) is by far the most precise analytical technique. It affords the opportunity to determine 206Pb/238U dates with unprecedented precision often <1‰ on single analyses or weighted mean dates derived from multiple analyses. Pretreatment protocols for zircon analysis, and community-wide innovations spurred on by EARTHTIME tends to be at the leading edge of technological development. Also, more and more Chinese researchers perform lots of laboratory work in improving the technique in China. Here we present the running condition, procedural blanks and zircon standards measurement results in the clean laboratory of the Guangzhou Institute of Geochemistry, Chinese Academy of Sciences (GIGCAS). The results show the total procedural blanks (Pbc) are below ∼1 pg mostly, suitable for the sample pretreatment and operation. The 206Pb/238U dates of R33 and 500 Ma solution are 419.88 ± 0.94 Ma (n = 7; MSWD = 6.8) and 500.50 ± 0.19 Ma (n = 9; MSWD = 0.84), respectively. These results demonstrate that the CA-ID-TIMS procedure is well established at GIGCAS. Our efforts are beneficial to the development of EARTHTIME-CN program. In particular, when this technique is combined with the SIMS technique, it provides an efficient way to solve a number of geochronological problems encountered in China and worldwide.

Keywords

• CA-ID-TIMS
• Zircon U–Pb geochronology
• Total procedural blank
• Common Pb
• Single zircon crystal