Data for: Metamorphic evolution of Daqingshan supracrustal rocks and garnet-bearing granite from the North China Craton: constraints from phase equilibria modelling, geochemistry, and SHRIMP U-Pb geochronology
Description
3.1 Electron probe microanalysis of minerals The mineral compositions for the supracrustal rocks and the garnetbearing granite were analysed by using an electron microprobe at the Key Laboratory of Orogen and Crustal Evolution of the Ministry of Education, Peking University, Beijing, China, using operating conditions of 5 kv accelerating voltage, 1 × 10–8 A beam current, and 1 μm spot diameter. For calibration, 53 standard samples of well-defined natural minerals (SPI Supplies, West Chester, Pennsylvania, USA) were used. The results are presented in SupplementaryTables 1 to 5. 3.2 Whole-rock geochemistry The major-element compositions of the minerals were measured using an Axios X-ray fluorescence (XRF) spectrometer at the China National Research Center for Geoanalysis, Beijing, China. Trace-element analysis was conducted using an Elan 9000 inductively coupled plasma mass spectrometer (ICP–MS; PerkinElmer, Waltham, Massachusetts, USA) with better than 10% accuracy of analysis. The major and trace element compositions and analytical precisions for each element are given in Supplementary Table 6. 3.3 Zircon U–Pb dating Zircon crystals were obtained using standard crushing and separation techniques, and U–Pb dating was conductedusing the SIMS II ion microprobe at the Beijing SIMS Center, Chinese Academy of Geological Sciences (CAGS). The hand-picked crystals together with the TEMORA standard, having a conventionally determined 206Pb/238U age of 417 Ma (Black et al., 2003), were cast in epoxy resin discs and were polished. All grains were photographed in both transmitted and reflected light and were then imaged using cathodoluminescence (CL) to reveal the internal structure and to identify the preferred locations for SIMS analysis. The U–Pb dating information is given in Supplementary Table 7.