EGU21-10216
https://doi.org/10.5194/egusphere-egu21-10216
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

On the lack of widespread bottom simulating reflectors in the Mediterranean Basin

Cristina Corradin1,2, Angelo Camerlenghi2, Michela Giustiniani2, Umberta Tinivella2, and Claudia Bertoni3
Cristina Corradin et al.
  • 1University of Trieste, Department of Mathematics and Geoscience, Trieste, Italy (cristina.corradin3@gmail.com)
  • 2National Institute of Oceanography and Applied Geophysics - OGS, Italy
  • 3Earth Sciences Department, University of Oxford, UK

In the Mediterranean Basin, gas hydrate bottom simulating reflectors (BSR) are absent, with very few and spatially limited exceptions occurring in Eastern Mediterranean mud volcanoes and in the Nile deep sea fan. This is in spite of widespread occurrence of hydrocarbon gases in the subsurface, mainly biogenic methane, from a wide range of stratigraphic intervals.
In this study we model the methane hydrate stability field using all available information on DSDP and ODP boreholes in the Western Mediterranean and in the Levant Basin, including the downhole changes of pore water salinity. The models take into account the consequent pore water density changes and use known estimates of geothermal gradient. None of the drilled sites were located on seismic profiles in which a BSR is present.
The modelled base of the stability field of methane hydrates is located variably within, below, or even above the drilled sedimentary section (the latter case implies that it is located in the water column). We discuss the results in terms of geodynamic environments, areal distribution of Messinian evaporites, upward ion diffusion from Messinian evaporites, organic carbon content, and the peculiar thermal structure of the Mediterranean water column.
We conclude that the cumulative effects of geological and geochemical environments make the Mediterranean Basin a region that is unfavorable to the existence of BSRs in the seismic record, and most likely to the existence of natural gas hydrates below the seabed.

How to cite: Corradin, C., Camerlenghi, A., Giustiniani, M., Tinivella, U., and Bertoni, C.: On the lack of widespread bottom simulating reflectors in the Mediterranean Basin, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-10216, https://doi.org/10.5194/egusphere-egu21-10216, 2021.

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