Paired Sr isotope (⁸⁷Sr/⁸⁶Sr, δ^88/86Sr) systematic of pore water profiles: A new perspective in marine weathering and seepage studies

The simultaneous and independent determination of the radiogenic (87Sr/86Sr) and the fractionation reflecting stable (!88/86Sr) Sr isotope ratio on pore waters, sediments and precipitates (e.g. carbonates and sulfates) opens a new perspective in the field of submarine weathering and Sr contribution to the ocean chemistry. Four initial case studies covering (1.) CO2 seeps of the Okinawa Trough (OT), (2.) mud volcanoes (MV) and mounds in the Gulf of Cadiz (GoC) and the (3.) Central American Fore Arc as well as first results from the (4.) Black Sea are conducted and reflect a stable Sr perspective on seeps from a broad range of geological settings. Referred to NIST-SRM-987, in this study the IAPSO seawater (SW) standard has a !88/86Sr of 0.39 ‰ (±0.03, 2SD). As a prominent systematic deviation the OT pore water (PW) data from a site with CO2 hydrate and liquid CO2 occurence show values ranging from 0.27 to 0.59 ‰ (286 to 64 cm sediment depth), accompanied by a weak inversely correlated trend from 0.2 to 0.15 ‰ for the corresponding bulk sediment (286 to 36 cm). In contradiction to a simple fluid/SW-mixing approach as driving mechanism for the PW stable Sr trend the 87Sr/86Sr signature stays within analytical uncertainty constant with depth (0.70980 (1)) and differs significantly from SW (0.70917 (1)) and the more radiogenic, slightly heterogeneous sediment (0.71892-0.71731). Potential explanation for the observed !88/86Sr trend and PW signatures heavier than SW are (a) strong fractionation processes enriching light isotopes in secondary precipitates and remineralisation products and heavier signatures in the remaining fluid and/or (b) preferential dissolution of heavier mineral phases. Examples for the latter kind of sediment component are determined in a detailed study of the Mercator MV (GoC) by high !88/86Sr ratios of 0.72 for authigenic and 0.92 ‰ for potentially extruded gypsum crystals. Combined with PW data from the other seep settings (0.2 to 0.52 ‰) a broad range of Sr contribution and fractionation processes becomes evident

2nd AtlantOS progress report plus International Scientific and Technical Advisory Board minutes and AtlantOS Legacy document

Prior to the 3rd annual meeting in month 32 a project progress report for the external project boards will be prepared to enable them to as good as possible prepared for the meeting and to ensure consequently that AtlantOS receives as constructive as possible recommendations from the board. The report together with the external summary board meeting report will be part of D11.

AtlantOS Exploitation Plan

Strategy for knowledge management, protection and exploitation of result

AtlantOS Data Management Plan Framework

Version No.: 1 Date: 30. Sep 201

AtlantOS Data Management Plan Framework

Version No.:1.2. -Implementation of AtlantOS Catalogue and GEOSS requirement