Almería Fossil Horizontal Reefs Reveal Pre-Messinian Mediterranean Conditions

Researchers from the University of Granada and the University of Almería have identified a unique assemblage of fossil coral reefs with horizontal growth forms in the Almería‑Níjar basin of southern Spain. Dated to about 6.5 million years ago, these bioherms reach up to 20 metres in height and were formed at depths of around 40 metres in exceptionally clear, warm waters.

The discovery, published in *Palaeogeography, Palaeoclimatology, Palaeoecology*, provides new insight into the marine environment that existed just before the Messinian Salinity Crisis, when the Mediterranean Sea largely evaporated. The horizontal layering of the corals indicates an adaptation to maximise light capture, suggesting high water transparency and elevated temperatures that differ from today’s conditions. These findings help scientists reconstruct ancient climate dynamics and improve understanding of how past reef ecosystems responded to environmental change.