On-line Gas Monitoring during Drilling - Data from the ICDP Expedition 5071, DIVE (Drilling the Ivrea-Verbano zonE), boreholes 5071_1_A and 5071_1_B

The drillings of the ICDP-DIVE project located in the Central part of the Ivrea-Verbano Zone at the Linea Cadorna in Migiandone near Ornavasso were accompanied by On-Line Gas Monitoring. During the drilling of both boreholes 5071_1_A (IGSN ICDP5071EH10001) and 5071_1_B (IGSN ICDP5071EH30001) O2, N2, 40Ar, 38Ar, 36Ar, CO2, CH4, H2, He and 222Rn were measured. The dataset contain for each species its concentration over time and depth. Gases were continuously recovered by degassing the drilling mud and quantified using two quadrupole mass spectrometers (QMS): an Omnistar GSD 300 (Pfeiffer Vacuum®, Germany) and a miniRUEDI (Gasometrix®, Switzerland) and an AlphaGUARD radon monitor (Bertin Technologies®, France). Baselines were corrected using the asymmetric least squares smoothing method from Eilers and Boelens (2005) resulting in an uncertainty not exceeding 3% for all the concentrations. All data provided are lag-time (and lag-depth) corrected with an error of less than 1 m.