One-million-year-old glacial landforms revealed under North Sea

Researchers have uncovered 1-million-year-old glacial and ocean current landforms buried nearly 1 kilometer beneath the North Sea, using advanced seismic technology. This groundbreaking discovery, led by an international team sheds new light on past climate and ice sheet behavior, particularly during the Mid-Pleistocene Transition—a period of global cooling. Scientists believe that by revealing the history of the Sea, formerly known as Mare Germanicum, they will be able to use it as a foundation to design a valuable framework for predicting the future of ice sheets in a warming world.

The study identified exceptionally well-preserved glacial landforms, created when an ice sheet originating in Norway extended toward the British Isles. These features, as reported on by the SciTechDaily publication, were discovered using 3D seismic data, a technology initially developed for assessing sediment suitability for oil, gas, or renewable energy infrastructures. This high-resolution imaging allowed researchers to map the landforms in unprecedented detail.

The identified features include streamlined shapes carved beneath the former ice sheet and ridges that record the retreat of the ice. Despite being 1 million years old, these landforms closely resemble those formed by more recent ice sheets. The findings, published in the American Science Advances journal, highlight the mechanisms of ice sheet retreat, with evidence suggesting that the former ice sheet’s frontal margin lifted and floated, leading to rapid retreat.

In addition to glacial landforms, the study also uncovered elongated furrows in the former seabed. These features, interpreted as being formed by strong ocean currents, predate the advance of the ice sheet. The discovery rewrites previous interpretations that attributed these furrows to glacial processes, offering new insights into the history of the North Sea.

The findings provide valuable information about how ice sheets in northwest Europe responded to long-term climate cooling approximately 1 million years ago. Lead author Dr. Dag Ottesen, from the Geological Survey of Norway, noted that the availability of 3D seismic data was instrumental in revealing these buried landscapes. This data also enabled the identification of ocean current furrows, challenging prior interpretations and enriching our understanding of the North Sea’s geological evolution.

Dr. Christine Batchelor, a member of the research team at Newcastle University emphasized that studying these ancient ice sheets is crucial for understanding how current ice sheets might react to ongoing climate warming. The Mid-Pleistocene Transition marked a shift in Earth’s climatic patterns, and the preserved landforms serve as a record of how ice sheets adapted to such changes.

Adjusting the perspective of previous research

“With our high-resolution data, we can see that the shape and size of the furrows is consistent with an origin as ocean current furrows,” said Dr. Ottesen. “This differs from previous interpretations of these features as glacial landforms, re-writing our understanding of North Sea glacial history."

These findings bring a new level of detail to the study of buried landforms, offering insights into the North Sea's geological evolution. The data reveal that strong ocean currents dominated the region prior to about 1 million years ago, after which advancing ice sheets became the primary influence on the area.

However, the researchers acknowledged a limitation: the precise age of the landforms remains uncertain. Dr. Batchelor highlighted the importance of acquiring long sediment cores to better pinpoint the timing of glacial events. Future research will aim to integrate seismic data with core samples to create a more comprehensive timeline of glacial and oceanographic history.

By Nazrin Sadigova