2011-12-14

Computer animation: How did the Messinian Salinity Crisis start?

We have created a 50 secs. computer animation of what we think the early stages of the Messinian salinity crisis looked like (following the interpretation we publish tomorrow in Nature):
Animator: M. Mantero (license: CC-BY-SA)
EnglishGeography of the Gibraltar Arc during the early stages of the Messinian Salinity Crisis (the period of restricted connection between the Mediterranean and the Altlantic). Our interpretation (scientific paper here) proposes that, at a depth of about 100 km, a piece of dense lithosphere detached from Iberia and sunk in the Earth's mantle. As a result, southern Iberia uplifted and the seaways that connected both seas shrunk progressively. However, this uplift had to compete with the erosion produced by the inflow of Atlantic water into the Med that compensates the excess of evaporation in this sea. This allowed a long-lived inflow stage that explains the enormous amount of salt precipitated in the bottom of the Mediterranean. As the tectonic uplift exceeded the erosion capacity of the inflow, the last seaway emerged and the Med became isolated. The lack of oceanic water supply and the arid climate of the Mediterranean sea both lead to a kilometric drawdown of its level. 
Español: Geografía del Arco de Gibraltar al inicio de la Crisis Salina del Mesiniense (el periodo de incomunicación entre el Mediterráneo y el Océano Atlántico), de acuerdo con la  interpretación que hacemos en la publicación que aparecerá en Nature. En el sur de la Peninsula Ibérica, a unos 100 km de profundidad, una parte de la litosfera se desprendió de la corteza terrestre y debido a su mayor densidad se hundió en el manto terrestre. Como resultado, el sur de Iberia se levantó y los estrechos que comunicaban ambos mares se redujeron progresivamente en profundidad. Este levantamiento tuvo que competir con la erosión producida por la entrada de agua Atlántica (necesaria para alimentar el Mediterráneo, que recibe menos agua de lluvia que la que evapora). Esto explicaría porqué el periodo de entrada de agua Atlántica fue tan prolongado dando lugar a la enorme cantidad de sal que se acumuló en el fondo del Mediterrráneo. Cuando la erosión del fondo del estrecho fue superada finalmente por el levantamiento tectónico, el canal de entrada quedó clausurado por completo, provocando que el clima seco del Mediterráneo hiciera descender rápidamente de su nivel más de un kilómetro.

  • Available under Creative Commons BY-SA license, mentioning the authorship: Concept: D. Garcia-Castellanos, Animator: M. Mantero
  • Free access to the multimedia files here.
    Also available in Commons
  • Related scientific paper [pdf]: Garcia-Castellanos, D., A. Villaseñor, 2011. Messinian salinity crisis regulated by competing tectonics and erosion at the Gibraltar Arc. Nature, 480, 359-363, doi:10.1038/nature10651 
  • More info on the research.

3 comments:

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  2. The idea of a sinking piece of lithosphere is great. Is this something that can also happen below the Andes or other similar places? That would imply periods of accelerated uplift/erosion/basinal sedimentation. Do you know of any sedimentary record that has been related with similar events?

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  3. Hi. The best known places are the Calabrian Arc and the subCarpathian foreland basin. Both have been explained as the result of slab tear propagation.

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