Ocean Drilling Program, United States

A tool to continuously monitor temperature, pressure, and conductivity (TPC) changes during Ocean Drilling Program (ODP) coring was tested at ODP Site 1226. TPC sensors are located on the face of the standard ODP advanced piston corer piston, and the data logging electronics and batteries are embedded within the piston. This tool operates autonomously and requires little shipboard attention. The objective is to monitor the TPC changes that occur in gas-rich and gas hydrate- bearing cores and to learn about the processes that occur during core collection. Gas evolution during core recovery alters the temperature and pressure conditions within the core barrel. By establishing families of ascent curves comprising TPC data from successive cores, variations in the relative amounts of gas and gas hydrates stored in sediments can be determined at individual sites and variations between sites can be assessed. Here, the performance of the TPC tool and the response of the tool at a site without significant quantities of sediment gas are described.