Guest “I couldn't think of this kind of slate if I tried” by David Middleton
By the American Association for the Advancement of Science of America…
While the Messinian salinity crisis and subsequent Zanclean megaflood represent one of the most incredible episodes in geological history… So incredible that the uppermost stage of the Miocene is called Messinian and the lowest stage of the Pliocene Zanclean… There were none mass extinction associated with it.
The AAAS of A article points to a very interesting paper:
Agiadi and her colleagues have now tracked the extinction and subsequent recovery with a comprehensive analysis of most fossils from this region, published today in Science Advances.
Fossils tell of a devastating mass extinction as the 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 move on to the thematic research work:
Biodiversity in the coral reef
Cooling directly affected temperature-sensitive organisms such as the tropical reef-building Z corals and their associated faunas (reef fishes and sharks), as well as bryozoans, and led to local extinctions of large populations, particularly in the eastern Mediterranean (Fig. 1) ( 40). Furthermore, the decline in water temperatures in the Mediterranean allowed an expansion of the distribution of boreal species in the basin during the Messinian, while highly thermophilic relict Tethyan species disappeared. Monegatti and Raffi ( 33 ) found that the MSC caused regional mass disappearances of molluscs but only a limited number of actual extinctions, and that the largest Messinian extinctions occurred in the Atlantic Ocean and were triggered by glaciers TG22, TG20, TG14, and TG12 during the MSC. In the Zanclean, the establishment of psychrospheric water masses in the Atlantic increased these effects (41). For example, the great white shark (Carcharodon carcharias) and the blue shark (Prionace glauca) first appeared worldwide at the Miocene/Pliocene boundary (42) and in the Mediterranean after the MSC (43).
The MSC played a critical role in the local extinction of shallow-water Z coral reefs, but was probably not the primary cause ( 40 , 44 ). As tropical reef corals, Z corals are very sensitive to temperature.
Agiadi et al., 2024
When is an extinction not an extinction? If it is a local extinction. The “limited number of actual extinctions” occurred in the Atlantic Ocean and were triggered by glacial episodes rather than the MSC.
The Messinian salinity crisis and the Zanclean megaflood are clearly “a story of upheaval and battles won and lost.” Gothic stories about profound changes, peaceful times and then great trauma.”
During the late Miocene, the Mediterranean literally dried up, depositing a layer of halite and gypsum about a mile thick (Messinian salinity crisis). Then, in the Early Pliocene, rapid flooding of the Mediterranean occurred (Zanclean megaflood), leading to the formation of the modern Mediterranean. The Zanclean Mega Flood was a doozy. If Gavin Schmidt's Silurian civilization had thrived on the Messinian Salt Flats during the late Miocene, the Zanclean megaflood would have wiped it 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 levels in the Mediterranean may have risen by 10 meters per day during the peak of water flow from the Atlantic to the Mediterranean basin.
That's what I call climate change!
“The greatest sea in history is dying”… because an unfounded reference to climate change
The MSC caused the deposition of a thick layer of evaporites (salt, gypsum, anhydrite, etc.) throughout the Mediterranean basin:
Schematic cross section of the Leviathan Basin (Bowman, 2011).
However, this is not a story of extinction and certainly not a story of a mass extinction. We can attribute this to a combination of good science journalism and bad science journalism.
References
Bowman, Steven. (2011). “Regional seismic interpretation of hydrocarbon potential offshore Syria”. GeoArabia. 16.
Konstantina Agiadi et al., Late Miocene transformation of biodiversity in the Mediterranean. Science. Adv. 10eadp1134 (2024). DOI:10.1126/sciadv.adp1134
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