The two headlands flanking it were known to the ancients as the Pillars of Hercules
The Rock of Gibraltar in Europe and, most often, Jebel Musa in Africa
Geography · Physical geography
The Strait of Gibraltar
refilled by the Zanclean flood about 5.3 million years ago
The 14 km gap between Spain and Morocco — the only natural link from the Atlantic to the Mediterranean
The narrow channel between the southern tip of Spain and the northern coast of Morocco, about 14 kilometres across at its narrowest and the only natural opening between the Atlantic Ocean and the Mediterranean Sea. The ancients called its flanking headlands the Pillars of Hercules and treated them as the edge of the known world. When it closed about six million years ago, the Mediterranean dried up.
How to spot them
- ▸The 14 km channel dividing Europe from Africa and the Atlantic from the Mediterranean
- ▸Quiz clue: 'Pillars of Hercules', 'Jebel Musa', 'Tarifa', 'Ceuta', 'Messinian salinity crisis'
- ▸Spain and Morocco face each other across it; Britain and Spain both hold territory on its shores
- ▸Water flows in on the surface and out at depth, because the Mediterranean evaporates faster than its rivers refill it
Key facts
About six million years ago it closed, and the Mediterranean evaporated almost to dryness
The Messinian salinity crisis, leaving kilometre-thick salt beds
It reopened around 5.3 million years ago in a catastrophic refilling of the sea beyond (5.3 Ma)
The Zanclean flood
At its narrowest it is only about 14 kilometres across, between Point Marroqui and Point Cires
Tarifa, on the European side, is the southernmost point of mainland Europe
Water pours in from the ocean on the surface while a saltier current slips out beneath
The Mediterranean loses far more to evaporation than its rivers supply
Two Spanish cities on the African shore face it, remnants of an older empire
Ceuta and Melilla, the EU's only land borders with Africa
Britain took the rock on its northern side in 1704 and was confirmed in possession in 1713 (1713)
Captured during the War of the Spanish Succession; ceded by the Treaty of Utrecht
A rail tunnel beneath it, linking two continents, has been studied by Spain and Morocco since the 1980s and never built
The proposed Gibraltar fixed link
Quick-fire facts
- •About 14 km wide at its narrowest and roughly 58 km long
- •It separates Spain and Gibraltar from Morocco and Spain's exclave of Ceuta
- •The only natural connection between the Atlantic Ocean and the Mediterranean Sea
- •The Pillars of Hercules were the Rock of Gibraltar (Calpe) and, usually, Jebel Musa (Abyla)
- •The Messinian salinity crisis, from about 5.96 to 5.33 million years ago, dried out the Mediterranean when the strait closed
- •The Zanclean flood refilled the basin, possibly within a couple of years
- •Tarifa, on the Spanish shore, is the southernmost point of continental Europe
- •Depths reach about 900 m, and a two-layer exchange of water drives Mediterranean circulation
- •A fixed rail link between Spain and Morocco beneath the strait has been studied since the 1980s but not built
Drill it — 8 cards
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Sources
- Encyclopaedia Britannica — Strait of Gibraltar
- D. Garcia-Castellanos et al., Nature 462 — Catastrophic flood of the Mediterranean after the Messinian salinity crisis