Scientific scope/objectives of project

The Mediterranean Salt Giant (MSG) was formed about 6 million years ago during the Messinian stage of the Miocene epoch when the restriction of water exchanges between the Atlantic Ocean and the Mediterranean Sea turned the Mediterranean into a hudge saline basin. The MSG exceeds a thickness of 3 km in the deep Mediterranean basins and contains more than one million cubic kilometres of evaporite salts (mainly halite and gypsum).

Extensive research has been carried out on the MSG since its discovery with deep-sea scientific drilling in 1970. SALTGIANT will train a new generation of 15 PhD students at the frontier between natural and social, fundamental and applied sciences with the aim to unravel what remains one of Earth Science’s most fascinating enigmas. The research objectives are organized into four research work packages.

Work packages

Work package 1 : Formation of the MSG

The aim of WP 1 is to develop a unified model that :

  • explains the formation of the MSG as a consequence of the tectonic and hydro-chemical evolution of the Mediterranean basin,
  • provides scenarios for the cycling of carbon and sulfur in the Mediterranean during the formation of the MSG.

WP 1 comprises ESR projects 1 to ESR 7 and is led by Wout Krijsman[MOU2] (Utrecht Universty).

ESR 1 : Late Miocene-Early Pliocene offshore onshore sedimentary records in the vicinity of Gibraltar

Supervised by Francisco Sierro(University of Salamanca).
The aim of ESR 1 project is to understand the evolution of the Strait of Gibraltar during the formation of the MSC.
Francesca Bulian will focus on the Gibraltar Strait and the potential role it played on the Atlantic-Mediterranean water exchange during the late Miocene. This project is based on boreholes already drilled in the Gulf of Cadiz and Guadalquivir, offshore Morocco and the Alboran Sea as well as outcrops near Gibraltar and the Gulf of Cadiz. These sites form a transect from the Atlantic to the Mediterranean along the Strait of Gibraltar along which Francesca will carry out micropaleontologic, sedimentary, geochemical and paleoceanographic studies aimed at reconstructing changes in the paleobathymetry and paleoenvironment along the Gibraltar Strait.

ESR 2 : Isostatic vertical motions during the Messinian salt giant or marginal vertical motions

Supervised by Daniel Garcia-Castellanos (CSIC).
The aim of ESR 2 project is to understand the vertical motions of the Mediterranean margins due to the extreme redistribution of isostatic load during the formation of the MSG.
Hanneke Heida will use large seismic data compilations with deep well logging, for 3 marginal regions: the Balearic promontory, the Alboran Basin, and the Po Basin. The seismic data will provide a detailed, 3D imaging of the erosion surface and salt cumulates characterizing the last stages of the formation of the MSG. Assessing the original vertical position of these features will test the consistency of competing proposed hypotheses on their formation across multiple study areas and will put the student in contact with top-quality, up-to-date data sources and geodynamic concepts.

ESR 3 : Balearic Basin Architecture

Supervised by Johanna Lofi and Philippe Pézard (CNRS Montpellier).
The aim of ESR 3 project is to understand the geological evolution of the Balearic promontory (Western Mediterranean) since the formation of the MSG by studying onshore and offshore sedimentary records and their post-deposition deformation.
The Balearic promontory is probably the only place in the Mediterranean basin where well-defined MSG deposits have been preserved. These MSG deposits are trapped in small basins lying at the present time at different depths between the present day coastline (including onshore outcrops) and the deep salt basins. Fadl Raad will focus on studying the MSG sedimentary records, both onshore and offshore, and on the post- MSG deformation (faults, vertical loading) over the promontory. Fadl will carry out a multidisciplinary research including sedimentary, petrophysical and geophysical investigations on a diverse dataset including onshore outcrops, core data (laboratory measurements), borehole geophysics (Techlog, Wellcad softwares), and seismic profiles (Petrel software).

ESR 4 : Sicilian Basin Architecture

Supervised by Antonio Caruso (UNIPA).
The aim of ESR 4 project is to acquire new insight from stratigraphic relationships between the evaporite series and the pre-Messinian sediments by carrying out detailed geological mapping of wedge-top basins of northwestern Sicily (Salemi-Calatafimi; Belice and Cimina) and the Hyblean plateau (Licodia Eubea).
Athina Tzevahirtzian will carry out a multidisciplinary stratigraphical, sedimentary and petrographical study on several key outcrops and mines located in wedge-top basins to understand their stratigraphic relation with the underlying pre-Messinian sediments. These wedge-top basins will be compared with the well-known Caltanissetta Basin and the Balearic basin by analyzing seismic profiles already available and those studied in marginal outcrops located in the Balearic promontory.

ESR 5 : Lago mare revisited

Supervised by Wout Krijgsman (Utrecht University).
The aim of ESR 5 project is to revisit the enigmatic Lago-mare interval and study the key sections on-land and in the deep sea (DSDP cores) on an E-W transect across the Mediterranean with a multi-disciplinary approach combining integrated bio- cyclostratigraphic analyses with high-resolution Sr-isotope records.
The transition from hypersaline evaporitic facies (gypsum and halite) to fresh-brackish Lago-mare facies implies a huge hydrological change in the region. Astronomical tuning of the sedimentary successions together with hydrological reconstructions will help to understand the paleoenvironmental variations in the basin that shows a progressive sequence of climate induced gypsum-marl cycles (Upper Evaporites of Sicily) towards brackish water deposits with fauna (mollusks and ostracods) originating from the Black Sea region. Strontium results will be coupled with salinity reconstructions through numerical models to obtain quantitative constraints.

ESR 6 : Hydrology of Mediterranean Marginal basins during the formation of the MSG

Supervised by Giovanni Aloisi (IPGP).
The aim of ESR 6 project is to reconstruct the hydrology of selected marginal basins of the Mediterranean Sea during the formation of the MSG using stable isotope tracers.
Laetitia Guibourdenche will work in tight collaboration with field-based ESRs (ESRs 1, 4, 5, 8), and mining sector partner KNAUF, to carry out a detailed sampling of primary gypsum deposits outcropping on land. The isotope composition of gypsum will be measured at the geochemical facilities of IPGP. In collaboration with ESR 7, Laetitia will apply simple numerical box models that simulate the isotopic composition of H2O and dissolved SO4 and Sr in marginal basins. In conjunction with the isotope composition of gypsum, these models will be used to deduce the hydrological cycle that dominated at the time of gypsum deposition in the marginal basins of the Mediterranean Sea, tackling the apparent contradiction of a marine-type evaporitic sequence bearing a continental isotope signal.

ESR 7 : Modelling the (bio-)geochemical evolution and circulation of Messinian brine

Supervised by Paul Meijer (Utrecht University).
The aim of ESR 7 project is to investigate the evolution of circulation, water properties and biogeochemistry of the Mediterranean basin during the formation of the MSG via numerical modelling.
This ESR project will achieve more refinement, both in terms of the water properties being modelled and their spatial distribution within the Messinian basins. Applying these refined models, Ronja Ebner will address the following fundamental questions that keep causing problems in the interpretation of observations from the sedimentary record of the MSG:
(a) how was salt distributed within the water column and between deep and shallow parts of the basin?;(b) was the water column density stratified and did it experience overturning (like the modern-day Dead Sea does)?; (c) did sulphate reduction inhibit gypsum formation in the deep part of a stratified Mediterranean during times of gypsum accumulation in the marginal basins?; (d) are marginal basins expected to be intrinsically different from the deeper parts?

Work package 2 : Deep life

The aim of WP 2 is to:

  • Explain the development of a exceptional and poorly-understood deep microbial biosphere in the MSG, providing a terrestrial analogue for the hypersaline environments of Mars where life forms might have been preserved ;
  • Characterize the microbial pathway for the formation of H2S (“sour gas”) via the microbial reduction of the mineral gypsum

WP 1 includes ESR 8 and ESR 9 projects and is led by Terry Mc Genity (University of Essex).

ESR 8 : The microbial sulphur-cycle in Messinian evaporites

Supervised by Jörn Peckmann (University of Hamburg).
The aim of ESR 8 project is to understand the development of a deep microbial biosphere in the MSG that (i) depends on the presence of the evaporitic sulphate-bearing minerals such as gypsum and (ii) produces toxic and corrosive hydrogen sulphide – “sour gas” – that is a drilling hazard in the hydrocarbon industry.
In close collaboration with the mining sector partner KNAUF and the University of Torino, Simon Rouwendaal will carry out a multidisciplinary petrographical, isotope geochemical and biomarker investigation of selected MSG rock samples that contain the traces of past microbial activity.
Simon will analyze microbial fossil-bearing samples using cutting-edge techniques to unravel the phylogenetic affiliation and biogeochemical functioning of ancient evaporitehosted microbes. This project is closely linked to ESR 5, 6 and 7, since the reconstruction of the depositional environment will greatly benefit from the conclusions on the paleo-hydrology and biogeochemical cycling of redox-sensitive element in the Mediterranean basins.

ESR 9 : Long-term survival of microbes in halite brine inclusions

Supervised by Terry Mc Genity(University of Essex).
The aim of ESR 9 project is to understand the survival of halophilic microbial communities inside the brine inclusions of halite, providing a model system for investigating the conditions that could have preserved traces of life in evaporites both on Earth (e.g. Messinian halite) and Mars.

The specific objectives are to:
1) Determine the influence of environmental conditions on the growth and survival of halophilic microbial communities and pure cultures inside halite crystals, by experimentally trapping cells inside brine inclusions, and periodically quantifying viable cells by a combination of labile molecular markers (such as mRNA), recultivation and microscopy. These experiments will be carried out both in Earth surface conditions and under Mars-simulation conditions (using the specialist facilities of partner DLR (German Aerospace Centre).
2) Develop a numerical model simulating fundamental energy flows in microbial cells in order to investigate survival in conditions of severe energy limitation when cells devote nearly all of their energy flow to somatic maintenance, rather than growth and reproduction.
3) Compare the halophilic microbiota living inside different types of halite crystals in Messinian evaporites and present-day analogues (e.g. sampled during a SALTGIANT field course based near the Dead Sea) by surface-sterilising halite followed by analysis of phylogenetic marker genes and cultivation in diverse media, in collaboration with the Icelandic biotechnology partner, MATIS.

Work package 3 : Drilling hazards

The aim of WP 3 is to develop a mechanistic and quantitative understanding of early salt deformation and sub-salt overpressure development that can be used by the oil industry to mitigate the risks associated with drilling in salt-capped hydrocarbon provinces.
WP 1 includes ESR 10 to ESR 13 projects and is led by Angelo Camerlenghi(OGS).

ESR 10 : Mediterranean Salt Structures
Supervised by Angelo Camerlenghi (OGS) and Anna Del Ben (University of Trieste).
The aim of ESR 10 project is to identify and classify salt structures in different geological environments of the Mediterranean basin making use of the available offshore multi-channel seismic reflection data including regional vintage public data, academic data, and industry data.
Salt deformation structures will be identified and classified through depth imaging in order to reconstruct geometries in detail. Seismic data and attributes will be used to identify evidence of overpressure below the salt and to link the deformation phases to gravitational spreading and gliding.
ESR 11 : Salt Tectonics in the Levantine Basin

Supervised by Zohar Gvirtzman (GSI).
The aim of ESR 11 project is to understand deformation in a young salt giant.
The Levant Basin provides a unique opportunity to model the early stage of salt tectonics when the sedimentary overburden is still relatively thin and the evaporitic unit is still intact.
The study will include a first phase of geological reconstruction and a second phase of numerical modelling.
The main scientific objectives are:

  1. to reconstruct the deformation history of the Levant basin since the formation of the MSG
  2. to understand how salt giants deform in response to basinward tilting and
    differential sedimentary loading
  3. to understand how deformation of subsurface salt affect overriding rocks
  4. and to understand strain partitioning within a multi-layered system of evaporites and clastics.
ESR 12 : Overpressure development in rapidly deposited salt basins. Application to the Salt Giant in the Mediterranean Basin

Supervised by Hector Marin-Moreno (NOC).
The aim of ESR 12 project is to quantify the amount and distribution of excess pore pressure below and within the Salt Giant on the Mediterranean basin; to evaluate the likely important role this plays on the evolution of the basin.
The objectives of this project are to constrain the petrophysical parameters of the salt, sub-salt and supra-salt formation from available seismic and borehole data from the Mediterranean Salt Giant and other analogous salt basins.
Then, using the available geochronological information, model the generation of overpressure by disequilibrium compaction, lateral movement of the salt, and mineral diagenesis at different Mediterranean geological environments from the Messinian to the present.
The ultimate aim is to better understand the role of overpressure in the evolution of basins containing rapidly deposited salt layers.

ESR 13 : Analogue modelling of combined crustal and Messinian salt deformation in Mediterranean

Supervised by Virginie Gaullierand Bruno Vendeville (CNRS Lille).
The aim of ESR 13 project is to use an analogue modeling approach combined with an analysis of natural Mediterranean examples to gain insight into the deformation styles of the MSG.
Gaia Travan will consider examples where there is active crustal tectonics and where the sedimentary cover comprises a mobile salt layer. The ESR will test various crustal tectonic settings (convergence, divergence, strike-slip) and observe how these basement movements are passed on at shallower levels (salt and sedimentary overburden). Experimental results will provide a set of shallow deformation patterns, each one associated with a specific crustal tectonic setting. These results, in return, will be applied to natural examples. This work will shed new light onto key tectonic regions of the MSG, including: regions of divergence (Northwestern Mediterranean basin, Tyrrhenian Sea), young or mature convergence (Algerian and Ligurian Margins, Ionian Sea, Mediterranean Ridge), oblique convergence (Eastern Cyprus Arc), and strike-slip (Levant Basin). Analogue modeling will also help understand the tectonic behavior of the sub-salt.

Work package 4 : Geo-Economics and History of Science and Technology

The aim of WP 4 is to:

  • Provide an integrated history of the discovery of the MSG, which contextualizes early researches in this field in relation with paradigm shifts of mid-twentieth century geosciences, international oceanographic and prospecting campaigns, and geopolitical tensions in the Mediterranean in the cold war ;
  • Study the economic and geopolitical implications of the mapping of big salt deposits because of their association with natural gas fields.

WP 4 includes ESR 14 and ESR 15 projects and is led by Nestor Herran (Sorbonne Université).

ESR 14 : Eastern Mediterranean oil and gas discoveries and regional geopolitics and economic development issues – Open position

Supervised by Eric Verdeil (SciencesPo).
The aim of ESR 14 project is to examine the impact of recent discoveries of natural gas under the MSG on the geopolitics and the economic development of the whole region.
The project asks whether the new resources and the cooperative/competitive strategies designed to exploit them can challenge the existing political and economic order at three levels: the regional one, between the region and the neighbouring ones, and the internal
country level. These discoveries can be a game changer at several levels. The research will carry in-depth fieldwork survey in one of the countries in order to connect the institutional (scientific, political and economical) framework built to exploit the new resources and the broader national and regional context regarding economic development, national unity and regional planning (relations between the Mediterranean shore region
and the whole country).

ESR 15 : Salt, Vessels and Maps: the Discovery of the Mediterranean Salt Giant

Supervised by Nestor Herranand David Aubin (Sorbonne Université).
The aim of ESR 15 project is to explore the history of the discovery of the MSG by framing it in a long-term perspective about salt research.
More specifically, it will provide a detailed case study of the Deep Sea Drilling Project (DSDP) campaigns that led to the discovery in the context of Cold War oceanography.
The project would involve the identification and compilation of key primary sources about research on the MSG and salt research in general, the inspection of relevant archives and the establishment of an oral history project to collect testimony of the main actors participating in 1960s drilling campaigns. The narrative will contextualize these researches in relation to post WW2 changes in the material culture of oceanography and geology, the development of prospecting campaigns, and the expansion of international cooperation during the Cold War. Indeed, the study will highlight the connections between key actors and research projects and technological, industrial and diplomatic concerns.