Laboratory of Geochemical Cycles and resources - LGC

Biogeochemical interactions between hydrosphere and oceanic lithosphere ©Ifremer

The axes of the « Laboratory of Geochemical Cycles and resources » (LGC) have been developed through a long-term research strategy aiming at understanding chemical exchanges between the hydrosphere and the oceanic lithosphere.

The laboratory studies the transport and transformation of chemical species (gas, metals, organic compounds) in different geological oceanic systems (e.g. passive and active margins, ridges). We apply an approach combining geology and geochemistry in order to understand the great elementary oceanic cycles (e.g. metals, carbons) which are involved in environmental issues that society faces (global change, energy and mineral resources and the potential impact associated with their exploitation). The laboratory works around two scientific research axes and a technical axis centered on the development and monitoring of in situ sampling and  measuring tools and also geochemical analyses, at sea, and at home in the lab. Our activities therefore work around three axes:

Axe 1: The study of hydrothermal processes and interaction in the deep and their impact on oceanic biochemistry

Ancient hydrothermal vents - MIR area ©HERMINE 2017, Ifremer

 This is an historical activity for the lab, studies focus on hydrothermal circulation and its consequences on metallic and organic element cycles.

TAG area - HERMINE cruise ©HERMINE 2017, Ifremer

Snake Pit - HERMINE cruise ©HERMINE 2017, Ifremer

Axe 2: Fluid migration in a sedimentary context

Carbonates sample on cold seeps ©MARSITECRUISE 2014, Ifremer Since the beginning of the years 2000 and the start of margin exploration through an interdisciplinary approach, the laboratory has opened up to the geochemical study of cold seeps and has developed considerable scientific expertise in carbonates and gas hydrates.

RAMAN spectroscopic measurement on bacterial mat ©MARSITECRUISE 2014, Ifremer

Vent carbonate chimney at cold seeps ©MARSITECRUISE 2014, Ifremer

Axe 3: In situ measures and geochemical tracers

This component plays a structural role in the organisation and functioning of the lab as it federates researchers and their similar analytical needs and uses similar exploration strategies and in situ measures to those used during at-sea expeditions. It ensures the generation and processing of measures and analyses and their quality control. An important part of the activity is devoted to the development, optimisation and validation of methodologies to resolve the technological and analytical issues at the heart of the laboratory's research.