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Environmental Chronology: Geological Formation of Malta (35–5 million years ago)

Tectonic Setting & Regional Context

Stratigraphic Sequence: Malta’s Bedrock Layers

Fossil Evidence and Paleoecology

Environmental and Climatic Conditions

Formation Processes and Land Emergence

Resulting Landscape Features

Geological Evidence Sites in Malta

Summary Table: Geological Formation Period (35–5 Ma)

Long-Term Legacy of This Period

Fossil remains - Seashells

Fossil remains in sedimentary rock at Tigne Point

The Maltese Islands during their Geological Formation (ca. 35–5 million years ago) is a time when tectonics, sedimentation, and sea-level change shaped the foundations of the modern Maltese landscape. This period spans the late Eocene, Oligocene, Miocene, and into the early Pliocene, and it is entirely pre-human.




Tectonic Setting & Regional Context


Where is Malta Geologically?

  • Malta lies on the Pelagian Block (African Plate), between the Sicily Channel Rift Zone and the Hellenic Arc.
  • The region was influenced by the collision of the African and Eurasian plates:
    • Led to uplift, faulting, and rifting.
    • Created shallow marine basins ideal for limestone deposition.




Stratigraphic Sequence: Malta’s Bedrock Layers


The Maltese Islands are made of marine sedimentary rock, mainly from the Oligocene to Miocene (33–5 million years ago):


Rock Formation Age (approx.) Main Composition Environmental Setting
Lower Coralline Limestone ~33–28 Ma (Oligocene) Hard limestone Shallow warm marine reefs
Globigerina Limestone ~28–16 Ma (Oligocene–Miocene) Soft, yellowish limestone Deeper, calmer marine environment (plankton‑rich)
Blue Clay ~16–12 Ma (Middle Miocene) Silty marl and clay Deeper marine basin, low energy
Greensand ~12–10 Ma (Miocene) Glauconitic sandstone Transition zone; shallow basin nearshore
Upper Coralline Limestone ~10–5 Ma (Late Miocene–Pliocene) Hard reef limestone Shallow reef platforms during uplift

Each layer reflects a specific marine environment, ranging from reef to deep ocean shelf.

Seashells embedded in sedimentary rock at Tigne Point

Various sea creatures embedded in sedimentary rock at Tigne Point




Fossil Evidence and Paleoecology

Fossils Found in Maltese Formations:

  • Lower & Upper Coralline Limestone: Corals, red algae, foraminifera, bryozoans.
  • Globigerina Limestone: Planktonic foraminifera (Globigerina species), mollusks, nummulites.
  • Blue Clay: Marine mollusks, microfossils, shark teeth.
  • Greensand: Fish bones, marine invertebrates.

These fossils tell us:

  • The region supported tropical to subtropical marine ecosystems.
  • High biological productivity, especially during the Globigerina phase.
  • No terrestrial animals — Malta was fully submerged during this period.




Environmental and Climatic Conditions


Period Climate Sea Level Environmental Effect
Oligocene (~34–23 Ma) Mild, cooling trend Moderate Reef‑building environments; widespread limestone formation
Miocene (~23–5 Ma) Warm, humid (early), then cooling High (early), falling (late) Sedimentation of clay and sand; shallow seas retreating by Late Miocene
Messinian Salinity Crisis (~5.96–5.33 Ma) Arid Catastrophic sea level drop Mediterranean Sea partially dried out; Malta may have briefly emerged



Formation Processes and Land Emergence


  • Malta’s layers accumulated under the sea for ~30 million years.
  • The rifting and uplift of the Pelagian Block raised the region.
  • By the end of the Miocene (~5 Ma), parts of the Maltese platform emerged above sea level, forming:
    • Ridges (Upper Coralline)
    • Depressions (Blue Clay valleys)

Key geological processes:

  • Faulting and tilting (e.g. Victoria Lines Fault)
  • Erosion of soft Blue Clay → created fertile valleys (e.g. Wied il-Għajn)
  • Karstification of limestones → caves, sinkholes, and fissures




Resulting Landscape Features


Feature Formed By
Dingli Cliffs Marine erosion of uplifted Upper Coralline Limestone
Victoria Lines Major fault zone (Great Fault) between limestone layers
Inland valleys Erosion of Blue Clay beneath Upper Coralline Limestone caps
Natural harbours Valleys later drowned by rising sea levels
Caves and sinkholes Limestone dissolution (karst processes)



Geological Evidence Sites in Malta


Site Significance
Dingli Cliffs Best exposure of Upper Coralline Limestone; dramatic uplift and marine erosion showcase Malta’s highest sea cliffs (~253 m).
Blue Clay at Għajn Tuffieħa Classic exposure of Blue Clay fostering slope instability and local spring formation where impermeable clay traps groundwater.
Globigerina quarries (e.g. Mqabba) Fossil‑rich Globigerina Limestone widely quarried and used as Malta’s traditional building stone (“franka”), renowned for its workability and heritage use.
Fomm ir‑Riħ Steep coastal section exposing Greensand and Blue Clay, as well as fault‑controlled syncline structure and varied stratigraphic layers.



Summary Table: Geological Formation Period (35–5 Ma)


Category Details
Plate tectonics African Plate collision led to rifting and uplift
Marine environments Varied from reefs to deep-sea basins
Rock types Mainly limestones, with clays and sands
Fossils Rich marine life: corals, mollusks, foraminifera
Sea-level effects Layers reflect both deep and shallow marine settings
Emergence of land Malta likely emerged ~5 Ma (Pliocene), after the Messinian Salinity Crisis



Long-Term Legacy of This Period


✔️ Landscape Structure:

  • All of Malta’s topography, coastlines, and soil distribution trace back to this geological foundation.

✔️ Building Stone:

  • Globigerina Limestone, used in temples and modern buildings, comes from this era.

✔️ Groundwater & Soil:

  • Blue Clay aquicludes and Upper Coralline aquifers drive today’s water supply and spring systems.



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