Why in news?
A study published in 2025 in the journal Global and Planetary Change reported the discovery of 117‑million‑year‑old mud waves buried under the Atlantic seabed near Guinea‑Bissau. The finding offers a glimpse into early ocean dynamics.
What are mud waves?
Mud waves are large, rhythmic sedimentary structures on the ocean floor. They form when persistent bottom currents push and pile up layers of fine sediments, creating wave‑like ridges that can extend over kilometres.
The Atlantic discovery
- Age and size: The newly described waves are about 117 million years old. Each wave stretches more than one kilometre and stands hundreds of metres high.
- Formation: In the early Cretaceous period, the North Atlantic was separated from the south. A spillover of dense, salty water from the young North Atlantic into southern basins stirred up massive quantities of mud and organic material. Powerful underwater currents then sculpted the mud into towering waves.
- Location: The waves lie roughly a kilometre beneath the sea floor west of present‑day Guinea‑Bissau.
Why it matters
Studying ancient mud waves helps scientists understand past ocean circulation, climate conditions and sediment transport. The Atlantic discovery sheds light on how connections between basins evolved and influenced marine ecosystems. It also highlights the dynamic nature of the ocean floor, which preserves records of Earth’s history.