Hundreds of millions of years, in minutes

Cryogenian · about 720–635 Ma

Ice ages leave their mark

Glaciers left glacial deposits that are preserved in Oman, including in the Jabal Akhdar area, where two glacial episodes are recorded around 740–700 and 650–630 million years ago. They are part of the evidence for the global “Snowball Earth” ice ages.

Evidence of ancient glaciation is part of our Jabal Akhdar geology and cultural hike.

Ediacaran · about 635–539 Ma

Microbial reefs: stromatolites

In warm shallow seas, mats of microbes trapped sediment layer by layer, building stromatolites that occur in Oman’s Neoproterozoic carbonate rocks.

Permian to Cretaceous

Tropical seas build a limestone platform

For a long span from the Permian to the Cretaceous, the edge of Arabia lay under shallow seas where thick limestones accumulated. Known as the Hajar Supergroup, these fossil-bearing limestones now form much of Jabal Akhdar.

See the layered super-sequences and fossils on our Jabal Akhdar route.

Late Cretaceous · about 96–95 Ma

New ocean floor is born

Magma rising at an oceanic spreading centre created the crust and mantle section now called the Samail (Semail) ophiolite. Zircon crystals in its gabbros have been dated to about 96–95 million years ago.

Our Muttrah GeoTrek stop explains the ophiolite sequence.

Late Cretaceous · from about 95 Ma

Ocean floor thrust onto Arabia

Soon after it formed, the slab of ocean floor was thrust (obducted) onto the edge of the Arabian continent. Rocks at its base — the metamorphic sole — formed at about the same time as its crust.

Late Cretaceous · about 80 Ma

The continental edge goes deep

Part of the Arabian continental margin was carried to great depth and transformed into high-pressure rocks, such as the eclogites near As Sifah, before returning to the surface — strongly folded on the way.

See the Sifah eclogite and the Wadi Al Mayh sheath fold on our Muscat route.

Paleogene · 66–23 Ma

Seas return: younger limestones

After the ophiolite was emplaced, shallow seas again covered parts of northern Oman and deposited younger, fossil-rich limestones, seen today around Muscat.

See fossils in Tertiary limestone on our Muscat route.

Cenozoic to today

Mountains rise, wadis cut down

Later uplift and folding shaped the Oman Mountains, including the great dome of Jabal Akhdar, while erosion carved deep wadis and canyons. Field guides of the Geological Society of Oman relate this mountain building to the collision of Arabia with Eurasia from about the Oligocene–Miocene onwards; the exact timing is still studied by geologists.

Grand Canyon View on our Muscat route looks across the super-sequences of Oman.

Today

Rocks still changing today

Where groundwater reacts with mantle peridotite, new carbonate minerals and travertine are still forming — a natural process studied for capturing carbon dioxide.