Electrical resistivity anomalies offshore a carbonate coastline: Evidence for freshened groundwater?.

Haroon, Amir , Micallef, Aaron , Jegen, Marion , Schwalenberg, Katrin, Karstens, Jens , Berndt, Christian , Garcia, Xavier, Kuehn, Michel, Rizzo, Enzo, Fusi, Nicoletta Chiara, Ahaneku, Chibuzo Valeria, Petronio, Lorenzo, Faghih, Zahra, Weymer, Bradley A. , De Biase, Michele and Chidichimo, Francesco (2021) Electrical resistivity anomalies offshore a carbonate coastline: Evidence for freshened groundwater?. Open Access Geophysical Research Letters, 48 (14). e2020GL091909. DOI 10.1029/2020GL091909.

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Supplementary data:

Abstract

Carbonate lithologies host considerable quantities of the Earth’s freshwater resources and partially supply a quarter of the global population with drinkable water. Carbonates constitute substantial amounts of the global coastlines, yet it is not known if and how they can sustain freshened groundwater offshore. Here, we use controlled source electromagnetic, seismic reflection, and core sample data to derive a lithological model for the eastern margin of the Maltese Islands and identify four distinct resistivity anomalies within the Upper Coralline Limestone, Globigerina Limestone, and Blue Clay formations. The anomalies hosted in the former are likely associated to low porosities, whereas the anomaly within the latter is indicative of pore fluid freshening. Hydrogeological modeling suggests that freshened pore fluids, emplaced during sea-level lowstands and preserved in low permeability units, are potentially still found within carbonate shelves. However, resource potential is low due to its relict nature and low permeability host environment.

Key points
● Geophysical data and hydrogeological modeling are applied to detect offshore freshened groundwater in a semi-arid carbonate setting
● Globigerina Limestone and Blue Clay located offshore SE Malta likely host a disconnected offshore freshened groundwater body
● The resistive anomalies within the Upper Coralline Limestone are interpreted as
localized porosity variations.Accepted Article
This article is protected by copyright. All rights reserved.
● This OFG was emplaced during sea-level lowstands and preserved in low permeability
units

Document Type: Article
Funder compliance: info:eu-repo/grantAgreement/EC/H2020/677898
Keywords: Offshore groundwater, electromagnetics, Inversion, Hydrogeological modelling
Research affiliation: OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-GDY Marine Geodynamics
Main POF Topic: PT8: Georesources
Refereed: Yes
Open Access Journal?: No
Publisher: AGU (American Geophysical Union), Wiley
Related URLs:
Projects: MARCAN, SMART, Digital Earth
Date Deposited: 01 Jul 2021 13:30
Last Modified: 07 Feb 2024 15:46
URI: https://oceanrep.geomar.de/id/eprint/53152

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