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.