Malta is built from five layers of rock laid down in an ancient sea. Each one shapes the landscape, the buildings and the life above it.
Explore the rock layers →Choose a layer, from the youngest at the top to the oldest at the bottom. Swipe along the bar on a phone.
Yellow to pale-grey limestone made of the shells of tiny floating sea creatures, laid down in deeper water than the coralline layers. It covers about 70% of the islands and wears down into gently rolling countryside. This is franka, the honey-coloured building stone of Malta's temples, churches and towns.
All five rock layers began as limy mud and sand on the seabed between about 30 and 5 million years ago, in the Oligocene and Miocene. The future islands lay far from any coast, so almost nothing washed in from land: the rocks are made mainly of the shells and skeletons of sea creatures and algae. They lie stacked like a layer cake, oldest at the bottom.
The islands only rose above the sea much later, in the Quaternary period, the last 2.6 million years.
Malta's fresh water comes from its rocks. Rain soaks down through the porous limestone until it meets the Blue Clay, which water cannot pass through. There it forms "perched" groundwater, which seeps out as springs along the hillsides. Deeper down, rain that reaches the Lower Coralline Limestone floats on salty sea water as a lens of fresh water at sea level, the islands' main groundwater store.
The hard Lower Coralline Limestone forms the sheer sea cliffs of Dingli and the south-west coast, and the caves and arches carved by the waves.
Globigerina Limestone (franka) is soft when first quarried and hardens in the air. It gives Valletta, Mdina, the prehistoric temples and village churches their warm honey colour, and was once exported for building abroad.
Once the land was above water, new deposits built up on top of the five layers: tufa from springs, rock debris on slopes, river sediment in the valleys, old buried soils, wind-blown silt, and material filling caves and cracks. Cave deposits such as those at Għar Dalam hold bones of animals that once lived here, including dwarf elephants and hippos.
Gozo's famous limestone arch at Dwejra collapsed into the sea during a storm in March 2017, a reminder that the coast is always changing.
Source: Environment and Resources Authority, Maltese Geology.
Seen from a satellite, the islands are the colour of their rock. The yellow-grey is limestone: bare ground, quarries, and the towns built from it. The north of Malta is a run of ridges and valleys all pointing the same way, the work of faults (see below). The high, cliffed coast faces south-west; the drowned valleys that make Malta's harbours open to the north-east, because the islands tilt gently that way.
Free maps and data you can explore yourself, from Malta's geological survey, the University of Malta and the government.
The official map, resurveyed by the British Geological Survey in 2021–22 for the Continental Shelf Department, which acts as Malta's geological survey. Seven layers: bedrock, surface deposits, made ground, faults, folds, collapse hollows and bedding. Free to explore online; the GIS files can be downloaded.
Open the interactive map ↗About the map ↗Aircraft laser scans of the whole country, flown in 2012 and again in 2018 at about 40 points per square metre (4 billion and 38 billion points). The University of Malta turned them into 3D views of the terrain, buildings and trees, one square kilometre at a time.
Open CloudIsle ↗LiDAR in Europe (EU Joint Research Centre, 2021, PDF) ↗How the 2012 survey combined laser scans of land and seabed, aerial photos and sonar to build Malta's first national spatial baseline (ERDF156 project, Malta Environment and Planning Authority).
Read the report (PDF, 6.8 MB) ↗Library record ↗The government's national spatial data portal (Malta Spatial Data Infrastructure), where official map layers shared under the EU's INSPIRE rules can be viewed and downloaded.
Open the geoportal ↗A preliminary 3D geological model built from the new map, borehole records and a terrain model. It shows the broad structure only, so it is not published: it can be viewed on request at the Continental Shelf Department.
About the model ↗Source: Continental Shelf Department, History of the Geological Map ↗
From about five million years ago the sea floor around Malta began to stretch and crack, opening a rift between Pantelleria, Linosa and Malta. Large faults running north-west to south-east, such as the Magħlaq Fault at Għar Lapsi, shaped the coastline.
A second set of faults, running east-north-east, cut the islands into blocks of high ridges and low valleys. The Victoria Lines Fault crosses Malta from Fomm ir-Riħ to Baħar iċ-Ċagħaq, and the British built the Victoria Lines fortifications along its steep edge in the late 1800s. In Gozo, the Qala Fault follows the south-east coast.
Source: Continental Shelf Department, Geological Map of the Maltese Islands.
Once the islands rose from the sea, caves and cracks in the rock slowly filled with soil and bones. Għar Dalam, a cave near Birżebbuġa, holds layers more than 160,000 years old with bones of dwarf elephants, hippos, small mammals and birds. Other layers hold deer, giant tortoises, giant swans, dormice and horses.
Animals like these could only have walked here, so the bones suggest Malta was joined to Sicily at times of low sea level. The cave also holds the earliest signs of people in Malta, about 8,500 years ago. Today it is a museum run by Heritage Malta.
In February 2026 the Environment and Resources Authority proposed the Dwejra Protection and Management Regulations, making the Dwejra–Qawra area of western Gozo Malta's first Site of Geological Importance. Its cliffs, sea stacks, the Inland Sea, valleys and reefs would be protected, with limits on digging, dumping, taking fossils, off-roading, light and noise, and fires in sensitive areas. A Dwejra Steering Committee would help ERA look after the site. The public consultation closed on 3 March 2026.
The regulations and consultation (ERA) ↗ · TVMnews report ↗ · Aqra bil-Malti ↗
Peter Gatt, president of the Malta Chamber of Geologists, argues that Malta needs a national geological service to manage rockfall risk before accidents happen, not after.
Written after a fatal rock collapse at Comino, the editorial calls for a national geological survey to watch over coastal hazards and public safety.
Peter Gatt notes that only 13 wells have been drilled on the Maltese continental shelf since the 1950s, so most of what lies under the seabed is still unknown.
The Chamber of Geologists' president warns that building rules in Malta lack geological checks and lag behind European standards.
ERA launches a public consultation on rules that would make Dwejra–Qawra in Gozo a protected Site of Geological Importance.
The first full revision of the map in almost 30 years, surveyed in 2021–22 at 1:10,000 for the Continental Shelf Department and free to explore online.