Dear Colleagues,

The call for abstracts for the upcoming Goldschmidt conference in Paris (13-18 August 2017; https://goldschmidt.info/2017/) has been opened on the first of January this year. For the first time this year Goldschmidt will host a session dedicated to the isotope geochemistry (both stable and radioactive) of the halogens (Cl, Br, I). The session will be convened by Masaaki Musashi (Shibaura Institute of Technology, Tokio) and myself (Hans Eggenkamp, Institut de Phyque du Globe de Paris). The keynote to the session will be given by Max Coleman (NASA Jet Propulsion Lab, Caltech). We already received messages that several well known halogen isotope geochemists plan to submit an abstract to this session.

The deadline to submit an abstract to this conference is April 1, 2017 (https://goldschmidt.info/2017/dates). We would like to invite all colleages working on halogen isotope subjects to consider submitting their abstract (https://goldschmidt.info/2017/abstracts) into this session.

The title of the session is 21g: Halogen Isotopes as Geochemical Tracers in Rocks, Sediments, Ground and Surface Waters on Earth and within the Solar System.

Convenors: Hans Eggenkamp, Masaaki Musashi
Keynote: Max Coleman (NASA Jet Propulsion Lab, Caltech)
Isotopes of halogens, especially chlorine, have been paid attention to not only as geochemical tracers of fluid flow during subduction processes at continental margins but also as signatures in aquifers that are essential to the occurrence of the life anywhere in the universe. Due to the fact that halogens (Cl, Br, I) in solution are normally present as conservative ions they are commonly used as tracers in all kind of aqueous fluids, rain-, pore-, ground- and formation waters, lakes, rivers and oceans. Isotopes of the halogens, both stable (δ37Cl, δ81Br) and radiogenic (36Cl, 129I) add an important layer of extra information beyond just the concentration data. Stable isotopes can for example be used as tracers for processes such as fluid flow, mixing, diffusion, dissolution/evaporation, ion-exchange, ion filtration and organic/inorganic reactions. Stable chlorine isotopes have even be measured, in-situ, on Mars. Radiogenic isotopes are important tracers to determine the age of groundwater (36Cl, t½= 301000y) or as tracer of man-produced nuclear fission (129I, t½=15.7Ma). Still the number of laboratories working with these isotopes is relatively limited. The reason for this is not very clear but may be related to either time consuming analytical procedures of the still not well understood processes that are responsible for their isotope distribution and fractionation. This session aims at bringing together both stable isotope and radiogenic isotope scientists in order to discuss new and improved analytical methods, new experimental data that will improve our understanding of these isotope systems and measurements of natural samples that show the usability of halogen isotopes as tracers. Further we hope that this session will improve contacts between the stable and radiogenic halogen isotope communities in order to improve their mutual understanding and hopefully to develop collaborative research projects.

We look forward to your abstracts   ;-)

With kind regards,

Masaaki Musashi
Hans Eggenkamp