Schematic of the drilling mud gas monitoring set-up onboard D/V Chikyu. Drilling mud gas monitoring set-up during IODP Exp. 338 (modified from ; 3D schematic © JAMSTEC). “Position D1” denotes the position of the SciGas degasser, whereas “Position D2” indicates the position of the Geoservices degasser. Sampling was either possible with the onboard IsoTube sampling system, or with a third-party sampling line including glass flask and Cu tubes. Prior to onboard measurements, the drilling mud gas was dried with a mist and moisture remover. The results of the measurements were stored in the onboard SSX datasystem.