Scientists Found Astonishing Lost Landforms Hidden a Half-Mile Beneath the Sea

• During the Mid-Pleistocene Transition (MPT), the Earth adopted a 100,000-year glacial-interglacial cycle compared to the previous 41,000-year cycle.

• Scientists have now discovered landforms created during the MPT, as glaciers retreated across what is now the North Sea.

• The new study relied on seismic data to locate possible areas for fossil fuel and green energy infrastructure.

For the past 12,000 years, human civilization has enjoyed generally warmer global temperatures during what’s known as the Holocene epoch. But when you delve deeper into Earth’s recent past, the climate has been far from uniform—especially in the northern hemisphere.

Today, for example, the planet experiences 100,000-year-long glacial-interglacial cycles. But earlier in the Quaternary Period, during the early Pleistocene epoch, the planet warmed and cooled on 41,000-year cycles (on average). This glacial change occurred around 1.2 to 0.8 million years ago, and is known today as the Mid-Pleistocene Transition, or MPT. Although some theories explain why this change occurred (a change in CO₂ levels, mostly), scientists still don’t know definitively why Earth changed up its glacial-interglacial cycle.

Now, an international team of scientists relying on seismic data gathered for surveying locations for oil, gas, and renewable energy infrastructure have spotted remarkable glacial landforms located one kilometer beneath the muddy bottom of the North Sea. Incredibly, a new study published in the journal Science Advances reports that these submerged landforms likely formed roughly 1 million years ago—smack dab in the middle of the MPT. This discovery could hopefully lead to insights on how ice sheets respond to climate change, as well as information about this mysterious climate transition itself.

“To fully understand the linkages between ice sheets and climate, we need to study how past ice sheets responded to long-term changes in climate,” Christine Batchelor, a co-author of the study and glaciologist from Newcastle University, said in a press statement. “Using modern seismic data, our results suggests that ice sheets in northwest Europe expanded significantly in response to climate cooling about 1 million years ago.”

The North Sea is a fascinating glacial region, which switches between wet and dry in step with the glacial-interglacial cycle. Previous investigations (also using seismic data gathered for fossil fuel extraction) have unearthed artifacts created by ancient humans who once inhabited the dry seabed, which is known to archaeologists more commonly as Doggerland. In this particular study, the ice sheet responsible for these newly-discovered formations centered over Norway and extended toward the British Isles.

“This study was made possible by the availability of 3D seismic data from the North Sea, which allowed us to examine the buried landforms in striking detail,” Dag Ottesen, lead author of the study from the Geological Survey of Norway, said in a press statement.

One of the biggest finds of the study details how features carved beneath the retreating ice sheet bear a striking resemblance to features formed by glaciers more recently. The submerged landforms’ unmodified states also illustrate exactly how the ice sheet retreated a million years ago.

And one layer below this glaciated geological “cake,” researchers discovered furrows formed by strong ocean currents that were once believed to be features formed by glaciers. These furrows highlight that the North Sea experienced strong ocean currents over 1 million years ago before becoming encased in ice.

Although these seismic scans create an incredible opportunity to understand this intensely dynamic geologic region, other measurements will be vital to fully flesh out our understanding of the changing geology of the North Sea region during the ever mysterious Mid-Pleistocene Transition.

“A wealth of seismic data are now available for the North Sea,” said Batchelor. “The next step is to acquire long sediment cores that can allow researchers to better understand the timing of glacial events.”

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