Deep beneath the waves of the North Sea, scientists have made a remarkable discovery that challenges established geological principles. Researchers from the University of Manchester uncovered hundreds of extensive sand mounds, some spanning several kilometers, that exhibit a phenomenon known as stratigraphic inversion. This unexpected finding reveals that younger, denser layers of sand have sunk beneath older, lighter sediments, creating a geologically inverted landscape.
Geophysicist Mads Huuse from the University of Manchester describes the significance of this discovery, stating, “This discovery reveals a geological process we haven’t seen before on this scale.” The traditional understanding of geological layers is that they follow a chronological order, with older layers positioned at the bottom and progressively newer layers on top. Stratigraphic inversion, in contrast, involves younger layers sinking down while older layers rise, which can occur due to various geological processes like rockslides or tectonic movements.
Using detailed seismic data, Huuse and his colleague, geophysicist Jan Erik Rudjord from oil company Aker BP, identified these sinkites at the North Sea’s bottom. Seismic waves behave differently when traveling through materials of varying densities. By analyzing this data, the researchers determined that large sections of the North Sea floor appeared to be upside down. The denser younger layers of sand displaced the more porous, older material, which was forced upwards to sit atop the denser sinkite structures.
The researchers have introduced the term “floatites” to describe the porous rafts that emerged from this process. Their analysis suggests that this stratigraphic inversion likely occurred around the Miocene-Pliocene boundary approximately 5.3 million years ago. The older sediments primarily consisted of lightweight, rigid layers filled with microscopic marine fossils, which were disrupted by geological events such as earthquakes. This led to the formation of sand that sank, ultimately resulting in the inversion of the sediment layers.
As the study continues, the team aims to refine and validate their interpretations, which could enhance understanding of the Earth’s crust beneath the ocean. This research has implications for assessing the integrity of underground reservoirs, sealing, and fluid migration—all crucial factors for carbon capture and storage initiatives. Huuse emphasizes, “Understanding how these sinkites formed could significantly change how we assess underground reservoirs.”
While the findings have generated interest, Huuse notes that the scientific community remains divided. “As with many scientific discoveries, there are many skeptical voices, but also many who voice their support for the new model.” The research has been published in the journal Communications Earth & Environment, marking a significant step forward in geological studies beneath the ocean.
