Marine regression

A marine regression is a geological process occurring when areas of submerged seafloor are exposed during a drop in sea level.

[1] According to one hypothesis, regressions may be linked to a "slowdown in sea-floor spreading, leading to a generalized drop in sea level (as the mid-ocean ridges would take up less space)...."[2] That view considers major marine regressions to be one aspect of a normal variation in rates of plate tectonic activity, which leads to major episodes of global volcanism like the Siberian Traps and the Deccan Traps, which in turn cause large extinction events.

The accumulation of all major landmasses into one body could have facilitated a regression by providing "a slight enlargement of the ocean basins as the great continents coalesced.

At the height of the last ice age, around 18,000 years ago, the global sea level was 120 to 130 m (390-425 ft) lower than today.

A cold spell around 6 million years ago was linked to an advance in glaciation, a marine regression, and the start of the Messinian salinity crisis in the Mediterranean basin.