Collaborative Research Project in the Framework of the Trilateral Program of the German Research Foundation

"Stable isotopes of strontium as a new proxy for continental weathering, pedogenesis processes and seawater temperature"

First phase: June 2010 - June 2012
Second phase: June 2013 - May 2016

Participants

Helmholtz-Zentrum für Ozeanforschung Kiel (GEOMAR), Germany (Coordination)
AlQuds University, AQU, Palestinian Authority
Geological Survey of Israel, GSI, Israel
The Hebrew University of Jerusalem, HUJI, Israel
Graz University of Technology, TU Graz, Austria
Christian-Albrechts-Universität zu Kiel, CAU, Germany

Abstract

Identifying the modes of traditional radiogenic strontium isotope ratios (⁸⁷Sr/⁸⁶Sr-Norm) and of non-traditional stable strontium isotope fractionation (δ^88/86Sr) in continental weathering products as well as in marine calcium carbonate is critical for interpreting the chemical and climatic history of the Earth. Following this approach a group of Palestinian, Israeli and German scientists initiated the TRION project to test the application of paired radiogenic and stable Sr isotopes (⁸⁷Sr/⁸⁶Sr*-δ^88/86Sr) for their potential to study continental weathering processes and biomineralization pathways as well as to determine the degree of temperature and rate dependent Sr isotope fractionation during the precipitation of organic and inorganic carbonates. This will extend and complete the conventional applications of the radiogenic Sr isotope ratios (⁸⁷Sr/⁸⁶Sr-Norm) in the field of the environmental and geosciences. Beyond the scientific goal, the TRION project is expected to contribute to the peace process in the Middle East by actively generating scientific communication, collaboration and sustainable networking among scientists from the Palestinian Authority and Israel. In order to achieve this societal goal TRION project is extended by a program of education and training for a group of joint Palestinian, Israeli and German students, sustainable capacity building and public outreach.

Scientific Goals

The findings (see publications) that there is natural and temperature dependent Sr isotope fractionation indicate that the origin of seawater Sr and its isotope composition is more complex than previously thought. In particular, we have to assume that fractionated Sr from continental sources as well as fractionated Sr from hydrothermal sources together with the temperature dependent Sr isotope fractionation during carbonate precipitation/dissolution exerts control on the paired ⁸⁷Sr/⁸⁶Sr*-δ^88/86Sr seawater ratios. Concerning the sources of Sr there is neither detailed information about the degree and mechanisms of Sr fractionation in rocks and soils nor in hydrothermal vents at mid ocean ridges. Similar to that the temperature dependency of Sr isotope fractionation of biologically precipitated carbonates and its species dependency are also not constrained and have still to be examined in more detail. All the information is important in order to understand the Sr isotope balance in the ocean and may help to better elucidate the link between continental weathering and atmospheric pCO₂.

1. Determine the mechanisms and degree of Sr isotope fractionation in continental rocks and soils being a major Sr source for the ocean.
2. Determine the mechanisms and degree of temperature dependent Sr isotope fractionation during the precipitation of organic and inorganic marine carbonates being a major sink for Sr in the ocean.