Contamination tracer testing with seabed drills: IODP Expedition 357

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

doi:10.5194/sd-23-39-2017

Abstract

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.

Highlights

International Ocean Discovery Program (IODP) Expedition 357 “Atlantis Massif Serpentinization and Life” aimed to collect intact sequences of shallow mantle core for examining serpentinization and deep biosphere processes (Früh-Green et al, 2015, 2016)
The use of synthetic tracers in drilling fluids to monitor for potential contamination of drill core samples for microbiological analysis has become fairly routine during microbiology-focused expeditions (Inagaki et al, 2015; Lever et al, 2006, 2013; Smith et al, 2000; Friese et al, 2017; Sauvage et al, 2016)
Orcutt et al.: Contamination tracer testing with seabed drills hole during seabed drilling (Früh-Green et al, 2017e). We describe such a drill-independent system and how it was used during seabed drilling by two seabed drill systems – the RD2 from the British Geological Survey, and the MARUMMeBo70 from the Center for Marine Environmental Sciences at the University of Bremen (MARUM; Germany) – during IODP Expedition 357 at the Atlantis Massif

Summary

Introduction

IODP Expedition 357 “Atlantis Massif Serpentinization and Life” aimed to collect intact sequences of shallow mantle core for examining serpentinization and deep biosphere processes (Früh-Green et al, 2015, 2016). To monitor PFC delivery during drilling operations, a variety of samples were collected from the seabed drills after drilling: core liner fluid samples, sensor package Niskin bottle samples, and exterior and interior core samples, as described in detail elsewhere (Früh-Green et al, 2017e).

Results

Conclusion