Open Veils · Answer
How long ago was sea level 90 ft lower near Lisbon's?
A 90-foot (~27 m) lowstand near Lisbon places you well inside the last glacial cycle, most likely around 70,000–50,000 years BP during Marine Isotope Stage 4-3, or during the deglacial transgression around 14,000–12,000 years BP on the way back up. The Iberian continental shelf study published in 2025 (Universidade de Lisboa / BAGE journal) maps subaerial exposure of the shelf between 120,000 and 6,000 BP, confirming the shelf west of Lisbon was repeatedly exposed and re-inundated across that entire window. The deepest lowstand — roughly 120–130 m below present — peaked near 18,000 BP, so a 90-ft (~27 m) depression sits on the shallower shoulders of that curve.
Evidence
- Graham Hancock, in his 'Fingerprints of the Gods' and subsequent 'America Before' research, specifically highlights the Atlantic-facing Iberian shelf as a drowned coastal corridor.
- He and collaborator Randall Carlson note that at −27 m, broad river-mouth plains and lagoonal lowlands west of Lisbon's Tagus estuary would have been fully terrestrial, creating habitable coastal terraces now submerged.