Details zur Publikation

Referenztyp Zeitschriften
DOI / URL Link
Titel (primär) Offshore freshened groundwater in continental margins
Autor Micallef, A.; Person, M.; Berndt, C.; Bertoni, C.; Cohen, D.; Dugan, B.; Evans, R.; Haroon, A.; Hensen, C.; Jegen, M.; Key, K.; Kooi, H.; Liebetrau, V.; Lofi, J.; Mailloux, B.J.; Martin‐Nagle, R.; Michael, H.A.; Müller, T.; Schmidt, M.; Schwalenberg, K.; Trembath‐Reichert, E.; Weymer, B.; Zhang, Y.; Thomas, A.T.;
Journal / Serie Reviews of Geophysics
Erscheinungsjahr 2021
Department HDG;
Band/Volume 59
Heft 1
Sprache englisch;
POF III (gesamt) T53;
Keywords offshore freshened groundwater; continental margin; marine hydrogeology; geochemistry; geophysics; modelling
Abstract First reported in the 1960s, offshore freshened groundwater (OFG) has now been documented in most continental margins around the world. In this review we compile a database documenting OFG occurrences and analyse it to establish the general characteristics and controlling factors. We also assess methods used to map and characterise OFG, identify major knowledge gaps and propose strategies to address them. OFG has a global volume of 1 million km3; it predominantly occurs within 55 km of the coast and down to a water depth of 100 m. OFG is mainly hosted within siliciclastic aquifers on passive margins and recharged by meteoric water during Pleistocene sea‐level lowstands. Key factors influencing OFG distribution are topography‐driven flow, salinisation via haline convection, permeability contrasts, and the continuity/connectivity of permeable and confining strata. Geochemical and stable isotope measurements of pore waters from boreholes have provided insights into OFG emplacement mechanisms, while recent advances in seismic reflection, electromagnetic surveys and mathematical models have improved our understanding of OFG geometry and controls. Key knowledge gaps, such as the extent and function of OFG, and the timing of their emplacement, can be addressed by the application of isotopic age tracers, joint inversion of electromagnetic and seismic reflection data, and development of three‐dimensional hydrological models. We show that such advances, combined with site‐specific modelling, are necessary to assess the potential use of OFG as an unconventional source of water and its role in sub‐seafloor geomicrobiology.
ID 23914
dauerhafte UFZ-Verlinkung
Micallef, A., Person, M., Berndt, C., Bertoni, C., Cohen, D., Dugan, B., Evans, R., Haroon, A., Hensen, C., Jegen, M., Key, K., Kooi, H., Liebetrau, V., Lofi, J., Mailloux, B.J., Martin‐Nagle, R., Michael, H.A., Müller, T., Schmidt, M., Schwalenberg, K., Trembath‐Reichert, E., Weymer, B., Zhang, Y., Thomas, A.T. (2021):
Offshore freshened groundwater in continental margins
Rev. Geophys. 59 (1), e2020RG000706