Sinkites reveal inverted subsurface structures and may affect carbon storage strategies. Their formation remains under active investigation.
Scientists have identified hundreds of massive sand formations hidden beneath the North Sea that seem to challenge fundamental geological assumptions and may hold significant relevance for energy exploration and carbon storage strategies.
By combining high-resolution 3D seismic imaging (which uses sound waves) with well data and rock samples collected from hundreds of drilling sites, a research team from the University of Manchester, working alongside industry partners, uncovered immense sand mounds—some stretching several kilometers across. These structures appear to have sunk into the Earth, pushing aside older, softer, and less dense layers beneath them.
This process has led to what is known as stratigraphic inversion, where the typical sequence of geological layering is flipped, placing younger sand deposits below older material—a pattern rarely seen at this magnitude.
Although this phenomenon has been documented on much smaller scales in the past, the newly discovered formations, which researchers have named “sinkites,” represent the largest known occurrence of this type of geologic reversal.
A new subsurface process revealed
The discovery, published in Communications Earth & Environment, raises new questions about how the subsurface behaves and may influence future approaches to carbon storage.
Professor Mads Huuse, the study’s lead author from The University of Manchester, explained: “This discovery reveals a geological process we haven’t seen before on this scale. What we’ve found are structures where dense sand has sunk into lighter sediments that floated to the top of the sand, effectively flipping the conventional layers we’d expect to see and creating huge mounds beneath the sea.”
Researchers believe these sinkites formed several million years ago, between the Late Miocene and Pliocene epochs, when seismic activity or rapid shifts in underground pressure likely caused the sand to liquefy and descend through existing fractures in the seabed. As the sand moved downward, it displaced the more porous but structurally stiffer layers beneath—mainly composed of ooze rafts made up of microscopic marine fossils and held together by shrinkage cracks—causing them to rise. These buoyant, uplifted layers have been named ‘floatites’ by the research team.
Implications for carbon storage and reservoir prediction
The finding could help scientists better predict where oil and gas might be trapped and where it’s safe to store carbon dioxide underground.
Prof Huuse said: “This research shows how fluids and sediments can move around in the Earth’s crust in unexpected ways. Understanding how these sinkites formed could significantly change how we assess underground reservoirs, sealing, and fluid migration — all of which are vital for carbon capture and storage”.
Now the team are busy documenting other examples of this process and assessing how exactly it impacts our understanding of subsurface reservoirs and sealing intervals.
Prof Huuse added: “As with many scientific discoveries, there are many skeptical voices, but also many who voice their support for the new model. Time and yet more research will tell just how widely applicable the model is.”
Reference: “Km-scale mounds and sinkites formed by buoyancy driven stratigraphic inversion” by Jan Erik Rudjord, and Mads Huuse, 21 June 2025, Communications Earth & Environment.
DOI: 10.1038/s43247-025-02398-8
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3 Comments
What it God’s name are you talking about, “carbon storage?” This is a joke. Great publication but your lack of discernment about reality and actual science is crippling. Let’s suck the atmosphere of Earth into a big set of pipes or tubes or whatever and then separate the carbon, and pump it into reservoirs. Great idea. Great.
Up there with cutting off balls on kids who are going through a phase in life. Quit ruining articles with poison pills.
The CO2 plans are real and test projects are already underway. I am disturbed by the idea the parties doing the CO2 “burial” profit from this. Fifty years later when some geological event induces massive outgassing from some CO2 burial site, will those who profited refund our money? No. They will socialize costs – once again – while privatizing profit.
I don’t know anything at all about any of this stuff.