Unique kind of valley discovered by geologists in the Maltese islands

Geologists have a documented a unique type of valley in the Maltese Islands.

This valley, which has a theatre-shaped head, wide and flat bed, and vertical side slopes, is formed by groundwater seepage rather erosion by surface water, which is the case for most valleys worldwide.

There are 30 such valleys spread across the Malta and Gozo, with the most prominent examples located in Mgarr (including Gnejna Valley), Mellieha and Nadur. These kinds of valleys can also be located on the seafloor, with the north eastern coast being the largest hotspot.

It is the first time groundwater seepage has demonstrated to form valleys in rock.

The international team of scientists behind the project have concluded such a discovery will help reconstruct environmental and water conditions in the past, which is very useful in places where the geological record is poor, such as in desert environments or potentially even Mars, where similar valleys have been documented.

The scientists have also show that the valleys are retreating at a rate of about 2cm per year in the form of block landslides. “This is an important consideration when assessing the hazard associated with these valleys, especially for owners of fields located above or within the valleys.”

The study, which is a product of the MARCAN project and was led by Prof. Aaron Micallef from the Department of Geosciences, has now been published in the international journal Geology.