Geochronology and Geochemistry of the Dismembered Ophiolites in the Xingshuwa Accretionary Complex in Southeastern Inner Mongolia
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Supporting data for "Petrology, Geochronology and Geochemistry of the Dismembered Ophiolites in the Xingshuwa Accretionary Complex in Southeastern Inner Mongolia: Implications for the Suture Zone between the Siberian and Sino-Korean Paleoplates in the Southeastern Central Asian Orogenic Belt" Table S1. Zircon U-Pb data of the metagabbro (P4B4-5) and tuffaceous sandstones (TD221-1 and TD221-3) in the Xingshuwa accretionary complex. Table S2. Major and trace elements of the mafic and ultramafic rocks in the Xingshuwa accretionary complex.
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1. Zircon U-Pb dating Zircons were extracted using conventional mineral separation techniques, including crushing, sieving, heavy liquid and hand picking. The separated zircons were then mounted in epoxy resin and polished to expose the cores of the grains for analysis. The detailed sample preparation is similar to that of sensitive high resolution ion microprobe (SHRIMP) U-Pb dating (Song et al., 2002). After carbon coating the resin disk, cathodoluminescence (CL) images of zircons were collected using a Nova Nano SEM 450 scanning electron microscope (SEM) at the Key Laboratory of Deep-Earth Dynamics of the Ministry of Natural Resources, China. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) U-Pb dating was performed at the Key Laboratory of Mineral Resources Evaluation in Northeast Asia, Ministry of Land and Resources, Changchun. Laser sampling was performed using a COMPexPro 102 ArF excimer system, and an Agilent 7900 ICP-MS instrument was used to acquire ion-signal intensities. Helium was used as a carrier gas for the ablated material. The detailed operating conditions for the laser ablation system and the ICP-MS instrument and the specifics of the data reduction process were the same as those described by Liu et al. (2008). During the experiment, sites for dating were selected on the basis of CL and photomicrograph images. A laser energy of 52 MJ, a frequency of 8 Hz and a spot size of 32 μm were used. The trace element compositions of zircon were calibrated against a multi-element reference material (SRM610) and an internal standard for Si. Zircon 91500 was used as the external standard for U-Pb dating and was analyzed twice every 5 analyses. Off-line selection, integration of the background, analyte signals, time-drift correction and quantitative calibration for the trace element analyses were performed using ICPMSDataCal (Liu et al., 2008, 2010). Concordia diagrams and weighted mean calculations were made using Isoplot (Ver 3.23) (Ludwig, 2003). 2. Major and trace element determinations Whole-rock major element contents were analyzed using a ZSX Primus II X-ray fluorescence spectrometer (XRF) at the Wuhan Shangpu Analysis Technology Co. LTD. The detailed analytical procedures were the same as those described in the national standard (GB/T 14506.28-2010) of China for 16 primary and secondary components in silicate rocks. The trace element compositions of the rocks were determined by ICP-MS at the Wuhan Shangpu Analysis Technology Co. LTD. The samples were digested by HF + HNO3 in Teflon bombs and analyzed with the laboratory’s Agilent 7700e ICP-MS. The detailed sample-digestion procedure for the ICP-MS analyses and the analytical precision and accuracy of trace element analyses were the same as those described by Liu et al. (2008). The international reference materials RGM-1 and BCR-2 were used to monitor the analyses, and the analytical uncertainties were estimated to be less than 5%.