On the Mediterranean coast west of the city of Alexandria, in Egypt, there is a belt of pumice embedded in the sedimentary stone that covers the landscape there. This article describes this belt and its possible origins.

Introduction:
On the Mediterranean coast west of the city of Alexandria, in Egypt, there is a belt of pumice embedded in the sedimentary stone that covers the landscape there.

As a youngster, I used to spend summers in Agami Abou Youssef, a resort area 18.5 km West of Alexandria, and I remember with curiosity wondering what this belt was.

Pumice is an unusually light rock due to the many bubbles inside it. Most pumice floats on water. It is formed by volcanic eruptions when molten lava is shot in the air with many bubbles of gas in it. As it cools, it solidifies into pumice.

Description:
The belt is about one meter or less wide, and is parallel to the coast line. It is about 600 meters away from the present coast line.

The pumice is visible on the surface, and is not covered by layers of any depth of the said sedimentary stone.

The pumice pieces are small, most being about 5 cm in diameter. Most are round or oblong. The color is mustard brownish.

The sedimentary stone that the pumice is embedded in is made of the exact same kind of sand that is on the coast there, hardening over the ages and composing this rock.

The width of the belt is unknown, and probably goes on for tens or hundreds of miles.

The area is now built up and the exact places where I saw this belt are now under gardens and villa foundations. However, there are still exposed areas a bit west of the original place. Perhaps on a future visit, I can try to find another area and get pictures and more exact measurements.

Origin:
Since the belt lies parallel to the sea coast, the pumice must have floated over the water, and then pushed by the waves to the shore. As the sand was transformed into stone, the pumice became embedded into it. Since pumice originates from volcanic eruptions, it is certain that an event like the Thera volcanic eruption is the source of this pumice.

Questions:
Some questions need to be answered in order to date this pumice correctly and identify its source: