Deep beneath the North Sea, scientists have made a remarkable discovery that challenges established geological principles. Researchers from the University of Manchester have identified hundreds of extensive sand mounds, some spanning several kilometers, which appear to be inverted. This phenomenon, described as “defying fundamental geological principles,” has never before been observed on such a large scale.
Geophysicist Mads Huuse of the University of Manchester stated, “This discovery reveals a geological process we haven’t seen before on this scale.” The mounds sit atop formations known as sinkites, resulting from a process called stratigraphic inversion. This occurs when younger, denser layers of sediment sink beneath older, lighter materials, effectively flipping the expected order of geological layers.
Geological formations typically follow a chronological order, with older layers situated at the bottom and progressively newer ones on top. Stratigraphic inversion disrupts this order, causing younger layers to displace older ones. Various factors, including rockslides and tectonic movements, can contribute to this inversion.
Using detailed seismic data, Huuse and his colleague, Jan Erik Rudjord from oil company Aker BP, mapped the seafloor of the North Sea. By analyzing how acoustic waves travel through different materials, the researchers discovered large sections of the seafloor exhibiting an unusual upside-down arrangement, with younger sand layers buried beneath their older counterparts.
The younger sand layers, which are denser and heavier, have gradually sunk over time. This process displaced the older, more porous materials, pushing them upward. The researchers have referred to these lighter, buoyant layers as “floatites.” They believe this geological activity likely occurred around 5.3 million years ago, marking the transition between the Miocene and Pliocene epochs.
The older materials primarily consist of lightweight, rigid, and porous layers formed from microscopic marine fossils, which were disrupted by seismic events. These disruptions likely fragmented the upper layer into sand, leading to the observed inversion. Over millions of years, sediment accumulation has further obscured the original structure, resulting in the undulating seafloor seen today.
As the research progresses, Huuse and his team aim to refine their interpretation of this geological phenomenon. Understanding the formation of these sinkites could provide valuable insights into the Earth’s crust beneath the ocean, including its weaknesses and stability, as well as the processes that can significantly alter these characteristics.
“This research shows how fluids and sediments can move around in the Earth’s crust in unexpected ways,” Huuse explained. “Understanding how these sinkites formed could significantly change how we assess underground reservoirs, sealing, and fluid migration—critical factors for carbon capture and storage.”
While some skeptics voice concerns regarding the new model, many support the innovative approach. Ongoing research will be essential to determine the broader applicability of these findings. This groundbreaking study has been published in the journal Communications Earth & Environment, marking a significant step forward in geophysical research.
