During Mesozoic and Cenozoic times, as the northwest corner of Africa converged on Iberia, it lifted the Betic-Rif mountain belts across southern Iberia and northwest Africa.
There the development of the intramontane Betic and Rif basins created two roughly-parallel marine gateways between the Atlantic Ocean and the Mediterranean Sea.
Dubbed the Betic and Rifian corridors, they gradually closed during the middle and late Miocene: perhaps several times.
In the late Miocene the closure of the Betic Corridor triggered the so-called "Messinian salinity crisis" (MSC), when the Mediterranean almost entirely dried out.
The start of the MSC was recently estimated astronomically at 5.96 mya, and it persisted for some 630,000 years until about 5.3 mya; see Animation: Messinian salinity crisis, at right.

After the initial drawdown and re-flooding, there followed more episodes—the total number is debated—of sea drawdowns and re-floodings for the duration of the MSC.
It ended when the Atlantic Ocean last re-flooded the basin—creating the Strait of Gibraltar and causing the Zanclean flood—at the end of the Miocene (5.33 mya).
Some research has suggested that a desiccation-flooding-desiccation cycle may have repeated several times, which could explain several events of large amounts of salt deposition.
Recent studies, however, show that repeated desiccation and re-flooding is unlikely from a geodynamic point of view.
During Mesozoic and Cenozoic times, as the northwest corner of Africa converged on Iberia, it lifted the Betic-Rif mountain belts across southern Iberia and northwest Africa. There the development of the intramontane Betic and Rif basins created two roughly-parallel marine gateways between the Atlantic Ocean and the Mediterranean Sea. Dubbed the Betic and Rifian corridors, they gradually closed during the middle and late Miocene: perhaps several times. In the late Miocene the closure of the Betic Corridor triggered the so-called "Messinian salinity crisis" (MSC), when the Mediterranean almost entirely dried out. The start of the MSC was recently estimated astronomically at 5.96 mya, and it persisted for some 630,000 years until about 5.3 mya; see Animation: Messinian salinity crisis, at right.
After the initial drawdown and re-flooding, there followed more episodes—the total number is debated—of sea drawdowns and re-floodings for the duration of the MSC. It ended when the Atlantic Ocean last re-flooded the basin—creating the Strait of Gibraltar and causing the Zanclean flood—at the end of the Miocene (5.33 mya). Some research has suggested that a desiccation-flooding-desiccation cycle may have repeated several times, which could explain several events of large amounts of salt deposition. Recent studies, however, show that repeated desiccation and re-flooding is unlikely from a geodynamic point of view.
Mediterranean Sea