This project has received funding from the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No 702001.

The research has been carried out at the Institut de Physique du Globe de Paris, Équipe de Geochimie des Isotopes Stables.

Experienced researcher: Dr Hans Eggenkamp
Supervisor: Prof Pierre Agrinier

To understand the redox variations and interactions between hydro-, bio- and atmosphere: the power of bromine stable isotopes.

The stable isotope geochemistry of chlorine (Cl) and bromine (Br) are considerably different. While most Cl isotope data are in the range from -1.21 to +0.40‰, Br isotope data are from -0.06 to +1.48‰. Interesting is that Br isotope variations are of the same magnitude as Cl isotope variations. Also Br isotope values of ancient evaporites are very positive (+0.6‰), impossible to explain from oceans with a modern isotope composition. These data are unexpected considering the small fractionation factors for Br compared to Cl.
The research we propose aims at understanding these observations and developing halogen stable isotopes to study fluid transport processes in porous media. This research has a great potential to understand the history and the migration of fluids in deep porous reservoirs which are considered for geological storage of CO2, H2 and hydrocarbons.

In the BRISOACTIONS project we study historical variations of Br isotope compositions in the earth's surface reservoirs. We study Br isotope variations in ancient evaporites that reflect Br isotope ratios of the oceans at the moment they were deposited.

We also study the geochemical processes that affect Cl and Br isotope variations. Isotope fractionation during ion-filtration that has never been studied in detail. This process is important to understand subsurface fluid flow and fractionation of ions and isotopes during fluid transport. We aim at studying Cl and Br isotope variations during this process. Also redox processes have hardly been studied. Oxidation processes can increase Br isotopes values more than Cl in spite of Br's much smaller isotope fractionation factors. During the early stage of the BRISOACTIONS project it became obvious that large Br isotope variations can be obtained through precipitation of salt from saturated solutions. At that moment we started to focus on those studies and oxidation-reduction research was stalled for possible later stages.

The final stage of the BRISOACTIONS project is to combine the new data with pre-known Br isotope geochemistry. So our observations we will be compared to the data obtained during earlier studies in order to understand better the geochemical cycles of Cl and Br. This will allow us to develop future research to continue to improve our knowledge on Cl and Br isotope variations as proxies to understand chemical cycles on earth, especially in fluids in deep porous reservoirs. To facilitate the comparison of new with older data we prepared a database containing all samples (published and as yet unpublished) from which Cl and Br isotope data are known.

On this website we present the results from the BRISOACTIONS project. The results that are presented and that are based on this project will be available from this website.

Published papers:
HGM Eggenkamp & P Louvat (2018) A simple distillation method to extract bromine from natural water and salt samples for isotope analysis by multi collector inductively coupled plasma mass spectrometry. Rapid Communications in Mass Spectrometry, 32;612-618 DOI:10.1002/rcm.8080.

Conference presentations:
First EAGE Workshop on Geochemistry in Operations and Production; Doha, Qatar, 3 to 5 October 2016 - Application of Cl and Br stable isotope variations in understanding aqueous fluids in sedimentary basins.
Goldschmidt 2017; Paris, France, 13 to 18 August 2017 - Relationships between δ81Br and δ37Cl in natural water and salt samples.
European Geosciences Union; Vienna, Austria, 8-13 April 2018 - Bromine stable isotope fractionation in evaporites.
Benelux Association of Stable Isotope Scientists; Liège, Belgium, 19-20 April 2018 - The fractionation of the stable isotopes of bromine in evaporites. (50M!!)

Database of all samples from which both the Cl AND the Br isotope ratio has been published. The database also contains the chemcial compositions of the samples so that relationships between the chemsitry and isotope compositons can be studied too.