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

Abstract: 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.