Guest “I couldn’t make this sort of schist up, even if I was trying” by David Middleton
From the American Association for the Advancement of Science of America…
While the Messinian Salinity Crisis and subsequent Zanclean Megaflood comprise one of the most incredible episodes in geologic history… So incredible that the uppermost stage of the Miocene epoch is named the Messinian and the lowermost stage of the Pliocene epoch is named the Zanclean… There was no MASS extinction associated with it.
The AAAS of A article references a very interesting paper:
Agiadi and her colleagues have now traced the extinctions and subsequent recovery with a comprehensive analysis of most of the fossils from this region, published today in Science Advances.
Fossils tell tale of devastating mass extinction when Mediterranean dried up
So… Not only was it not a mass extinction.., It was an extinction from which there was a recovery. Why use the word “extinction” at all? Let’s go to the subject research paper:
Coral reef biodiversity
The cooling directly affected temperature-sensitive organisms such as the tropical reef-building z-corals and their associated faunas (reef fishes and sharks) and bryozoans, leading to local extinction of vast populations, particularly in the Eastern Mediterranean (Fig. 1) (40). In addition, the decrease of water temperatures in the Mediterranean allowed boreal species to expand their distribution to the basin during the Messinian, while strongly thermophilic Tethyan relic species disappeared. Monegatti and Raffi (33) noted that the MSC caused regional mass disappearances of molluscs but only a limited number of actual extinctions and that the greatest Messinian extinctions took place in the Atlantic Ocean and were triggered by the TG22, TG20, TG14, and TG12 glacials during the MSC. In the Zanclean, the establishment of psychrospheric water masses in the Atlantic further exacerbated this impact (41). For example, the great white shark (Carcharodon carcharias) and the blue shark (Prionace glauca) first appeared globally at the Miocene/Pliocene boundary (42) and in the Mediterranean after the MSC (43).
The MSC played a crucial role in the local extinction of shallow-water z-coral reefs, but it was probably not the main driver (40, 44). Z-corals, as tropical reef corals, are highly sensitive to temperature.
Agiadi et al., 2024
When is an extinction not an extinction? When it’s a local extinction. The “limited number of actual extinctions” occurred in the Atlantic Ocean and were triggered by glacial episodes, not the MSC.
The Messinian Salinity Crisis and Zanclean Megaflood clearly comprise “a tale of upheaval and battles won and lost. Gothic tales of sweeping change, peaceful times, and then great trauma again.“
During the late Miocene, the Mediterranean Sea literally dried up and deposited a layer of halite and gypsum about a mile thick (Messinian salinity crisis). Then in the early Pliocene Epoch, the Mediterranean rapidly flooded (Zanclean megaflood), leading to the formation of the modern Mediterranean Sea. The Zanclean megaflood was a doozy. If Gavin Schmidt’s Silurian civilization had been thriving on the Messinian salt flats during the Late Miocene, the Zanclean megaflood would have wiped them out without a trace. The transition from the MSC to the Zanclean megaflood marks the transition from the Miocene to the Pliocene. It left a serious mark on the stratigraphic record.
Some reconstructions of the Zanclean megaflood suggest that sea level in the Mediterranean could have risen at a rate of 10 meters per day during the peak flow of water from the Atlantic into the Mediterranean basin.
Now, that’s what I call climate change!
“History’s Greatest Sea is Dying”… Because Gratuitous Reference to Climate Change
The MSC caused the deposition of a thick layer of evaporites (salt, gypsum, anhydrite, etc.) across the Mediterranean basin:
However, this is not an extinction story, much less a mass extinction story. We can chalk this up to a combination of good science and bad science journalism.
References
Bowman, Steven. (2011). “Regional seismic interpretation of the hydrocarbon prospectivity of offshore Syria”. GeoArabia. 16.
Konstantina Agiadi et al., Late Miocene transformation of Mediterranean Sea biodiversity. Sci. Adv. 10, eadp1134 (2024). DOI:10.1126/sciadv.adp1134
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