Geology of Malta and Gozo

Carolina Perez

The present is the key to the past. Charles LyellGeology of Malta and Gozo

General CaracteristicsMalta is entirely composed of sedimentary rocks.Indeed, all land comprising the territory of Malta was formed under water through the slow but steady stratification of sediment particles settle under water.The oldest sediments were deposited in the Mediterranean Sea around 35 million years ago while the most recent layers were only formed a mere 7 million years ago.

The Maltese rock layers are subdivided into five distinct types, starting from the bottom as follows:

Lower Coralline LimestoneGlobigerina LimestoneBlue ClayGreensandUpper Coralline Limestone

Upper Coralline Limestone (Il-Qawwi)Greensands (Il-Gebla s-Safra)Blue Clay (Tafal)Globigerina Limestone (Il-Franka)Lower Coralline Limestone (Zonqor)

Upper Coralline Limestone PlateauGreensandsBlue ClayGlobigerina LimestoneLower Coralline LimestoneQammieh, MaltaS. BajadaMaltese StratesLower Coralline Limstone: It is the oldest rock layer and forms the base of the entire Maltese rock succession. It is generally found exposed on cliff sides facing the sea, such as Ta Cenc (Gozo) and Dingli Cliffs. It is a very hard rock and thus forms a rugged and sharp pointed land surface. It reaches a maximum thickness of 140 metres. Its colour ranges from, pale grey to red.Globerina Limestone: This is the thickest layer and can be found in central and the south of Malta. It is harder than the Blue Clay but softer than the Upper Coralline Limestone. It is extracted from quarries and used for building purposes. It is also used for sculpture and decorative work in stone.Blue clay: It is very soft and erodes quickly giving rise to cone-shaped slopes.This rock can be found in the north western part of Malta and north east of Gozo. These slopes are turned into terraced fields with rubble walls to hold the soil in place. It is impermeable and so it holds water which can be used for irrigation purposes.Greensands: It has a greenish-yellow colour and when it is exposed it turns into orange. Its the thinnest layer and reaches a maximum thickness of 11 metres at Il-Gelmus in Gozo It is friable and contains many fragments of fossils.Upper Coralline Limestone: This is the youngest rock strata and is a very hard rock. It is used as filler for road surfacing. It can be found mainly in the northern part of Malta .

We can find many different conditions to form the rocks in differents ages:Depth of seaSunlightDistance from nearest landDirection and force of sea currentsDifferent species of organisms. It is important to appreciate the marine origin of these islands.It also helps explain why Malta lacks natural resources such as metals and why our fossils generally comprise marine organisms rather than land animals or plants.It is a clear example about uniformism law regarding to chronological events through the time.