Clumped Isotope data on calcite veins found in the fault core of Gubbio Fault, Italy

Thin sections were microsampled and powdered samples were analyzed (δ18O, δ13C, Δ47) in the Paleo3 Laboratory at North Carolina State University (NCSU). Samples (500-1500µg) were digested with phosphoric acid at 70°C on a Nu Carb automated carbonate device, and resultant CO2 was cryogenically separated and passed through a Porapak Q trap at -30°C, then transferred via dual inlet to a Nu Perspective IS isotope ratio mass spectrometer configured to measure m/z ratios for masses 44–49, which produced δ18O, δ13C, and Δ47 values reported relative to the Vienna Peedee Belemnite (VPDB) and the absolute reference frame (ARF/CDES; Dennis et al., 2011). The purpose of this study was to independently verify temperature estimates from calcite twinning thermometry.岩薄片经微取样后制成粉末样品，于北卡罗来纳州立大学（North Carolina State University，NCSU）Paleo3实验室开展δ¹⁸O、δ¹³C与Δ₄₇三项同位素分析。称取500~1500 μg的样品粉末，于70℃下在Nu Carb自动碳酸盐反应装置中以磷酸进行酸解；生成的二氧化碳经低温分离后，在-30℃下通过Porapak Q捕集阱，随后通过双进样系统导入Nu Perspective IS型同位素比值质谱仪。该仪器设置为检测质荷比为44至49的离子信号，由此得到的δ¹⁸O、δ¹³C及Δ₄₇数值均以维也纳佩迪箭石标准（Vienna Peedee Belemnite，VPDB）与绝对参考框架（absolute reference frame，ARF/CDES；Dennis等，2011）为参照基准。本研究旨在独立验证方解石双晶测温法（calcite twinning thermometry）所得的温度估算结果。