Melt-carbonate interaction in the Sulu orogen: Implications for CO2 release in the continental subduction zone
Description
This dataset presents geochemical analyses including U-Th-Pb geochronology and trace element concentrations for titanite, alongside major element compositional data for all minerals analyzed in the study.
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4.1. In-situ U-Pb dating and trace element dating of titanite Fifteen titanite grains with one hundred and thirty-three test points were selected for U-Pb dating and trace element dating. The determinations were performed at Wuhan SampleSolution Analytical Technology Co., Ltd. (Wuhan, China) utilizing laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Ablation was achieved using a GeolasPro HD system equipped with a COMPexPro 102 ArF excimer laser (193 nm wavelength, 200 mJ maximum energy) and a MicroLas optical setup. Ion signal detection employed an Agilent 7900 ICP-MS. Analyses utilized a spot size of 44 μm, repetition rate of 3 Hz, and laser fluence fixed at 5 J/cm². Following established protocols (Luo et al., 2018), helium served as the carrier gas within the ablation cell, merging with argon (makeup gas) downstream. Signal stability was enhanced and mercury interference minimized using a dedicated signal-smoothing and mercury-removal apparatus (Hu et al., 2015). Each analysis comprised a 20-second background acquisition phase followed by 50 seconds of sample ablation. External standardization for U-Pb dating involved zircon 91500 (Wiedenbeck et al., 1995) to correct for Pb/U fractionation and instrumental mass bias, with titanite MKED1 analyzed as an unknown. Data processing, encompassing background and analyte signal selection/integration, time-drift correction, and quantitative calibration for both trace elements and U-Pb ages, was conducted using ICPMSDataCal software (Liu et al., 2010). Concordia diagram construction and weighted mean age calculations were performed with Isoplot/Ex_ver3 (Ludwig, 2003). 4.2. In-situ major element dating of minerals Major element compositions of minerals (K-feldspar, plagioclase, diopside, tremolite, olivine, serpentine, phlogopite, calcite, dolomite) were determined using a JEOL JXA-8230 electron probe microanalyzer equipped with four wavelength-dispersive spectrometers (WDS) at the Center for Global Tectonics, School of Earth Sciences, China University of Geosciences (Wuhan). Analytical conditions (15 kV accelerating voltage, 20 nA probe current, 1 µm beam diameter) followed Wang et al. (2019) and Ning et al. (2019). Dwell times were 10s on element peaks and half that on background locations adjacent to peaks. Raw X-ray intensities underwent ZAF (atomic number, absorption, fluorescence) correction. The following standards were used: Sanidine (K), Pyrope Garnet (Fe, Al), Diopside (Ca, Mg), Jadeite (Na), Rhodonite (Mn), Olivine (Si), Rutile (Ti) and Apatite (P).
Institutions
- China University of Geosciences