Articles | Volume 23
Technical development
30 Nov 2017
Technical development |  | 30 Nov 2017

Contamination tracer testing with seabed drills: IODP Expedition 357

Beth N. Orcutt, Markus Bergenthal, Tim Freudenthal, David Smith, Marvin D. Lilley, Luzie Schnieders, Sophie Green, and Gretchen L. Früh-Green

Abstract. IODP Expedition 357 utilized seabed drills for the first time in the history of the ocean drilling program, with the aim of collecting intact sequences of shallow mantle core from the Atlantis Massif to examine serpentinization processes and the deep biosphere. This novel drilling approach required the development of a new remote seafloor system for delivering synthetic tracers during drilling to assess for possible sample contamination. Here, we describe this new tracer delivery system, assess the performance of the system during the expedition, provide an overview of the quality of the core samples collected for deep biosphere investigations based on tracer concentrations, and make recommendations for future applications of the system.

Short summary
This paper describes a new tracer delivery system designed for use with seabed drills. The motivation for this system was the need to assess for possible seawater contamination of hard rock cores intended for microbiological and geochemical assessment. During IODP Expedition 357, the system was tested and proven to deliver a synthetic tracer at target saturating concentrations, which was useful for assessing sample contamination and handling procedures.