An international team of researchers, including a glaciologist from Newcastle University, UK, has made an extraordinary discovery beneath the North Sea: remarkably well-preserved glacial landforms buried almost a kilometer below the seabed. These landforms, which date back approximately one million years, were revealed using advanced seismic (sound wave) data, marking a significant breakthrough in understanding the glacial history of northern Europe and its relationship to climate change.
The study, published in the prestigious journal Science Advances, suggests that these landforms were formed during a critical period of global cooling, known as the Mid-Pleistocene Transition. During this time, an ice sheet centered over Norway expanded significantly toward the British Isles. The discovery is crucial because the timing of this ice advance corresponds with a period of dramatic climate shifts, helping to refine our understanding of how ancient ice sheets responded to global cooling events.
Understanding past ice sheet behavior is essential for predicting how modern ice sheets, such as those in Greenland and Antarctica, might respond to current climate warming. Ice sheets play a central role in global climate systems and contribute to sea-level changes. Therefore, the preservation of these glacial landforms, despite their burial under thick layers of sediment, provides valuable insights into the dynamic interaction between ice sheets and climate.
A key contributor to the research, Dr. Christine Batchelor, Senior Lecturer in Physical Geography at Newcastle University, emphasized the importance of studying past ice sheet behavior to understand how these vast frozen systems responded to long-term climate changes. “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,” said Dr. Batchelor. “Using modern seismic data, our results suggest that ice sheets in northwest Europe expanded significantly in response to climate cooling about 1 million years ago.”
The team’s findings were made possible by the use of 3D seismic technology, which was originally developed for oil and gas exploration but has since been repurposed for geological research. Seismic data, which uses sound waves to map the subsurface of the Earth, allowed the researchers to uncover detailed images of the buried landforms. These data revealed a landscape that includes streamlined features carved by ice as it moved across the land, as well as ridges that mark the retreat of the ice sheet.
Dr. Dag Ottesen, from the Geological Survey of Norway and the paper’s lead author, highlighted how the 3D seismic data provided unprecedented detail about these landforms. “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,” Dr. Ottesen explained. The high resolution of the seismic data provided an opportunity to map and interpret the landforms with a level of clarity that was previously impossible.
The researchers identified several distinctive glacial features buried beneath the seabed, including streamlined forms that indicate how the ice sheet once advanced and reshaped the landscape. These features are similar in appearance to those created by ice sheets in more recent geological periods, suggesting that despite their ancient age, the landforms have remained remarkably well preserved.
One of the most fascinating aspects of the discovery is the nature of the ice sheet’s retreat. The researchers concluded that the ice sheet likely retreated rapidly by a process known as “lift-off,” where the front edge of the ice sheet rose off the ground and began to float on the underlying water. This process is essential for understanding how ice sheets can undergo dramatic changes in response to warming climates. The fact that the landforms remain so well preserved suggests that the retreat occurred relatively quickly, before these features could be significantly modified by other processes.
In addition to the glacial landforms, the research team also discovered elongated furrows carved into the former seabed. These furrows, which were interpreted as having been formed by strong ocean currents, are even more deeply buried than the glacial landforms. Their presence suggests that the North Sea was influenced by powerful ocean currents prior to the advance of the ice sheet. This discovery challenges previous interpretations of these features, which were thought to have been created by glacial activity, and offers new insights into the environmental conditions that existed before the ice sheets expanded across the region.
Dr. Ottesen explained, “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. This differs from previous interpretations of these features as glacial landforms, re-writing our understanding of North Sea glacial history.” This new interpretation has profound implications for how scientists view the evolution of the North Sea’s geological history and the factors that shaped its landscape.
The study also sheds light on the broader changes in the North Sea region’s environment over the past million years. Prior to the expansion of the ice sheets, the area was likely characterized by strong ocean currents that shaped the seabed. After the ice sheets began to expand, these currents were increasingly influenced by the advancing glaciers, leading to the landforms that have now been uncovered.
Despite the groundbreaking nature of the findings, the researchers acknowledge that there is still much to be learned about the precise timing of these glacial events. The seismic data provides a detailed image of the buried landforms, but the exact age of these features remains uncertain. As Dr. Batchelor noted, “A wealth of seismic data are now available for the North Sea. The next step is to acquire long sediment cores that can allow researchers to better understand the timing of glacial events.” These sediment cores, which could be extracted from the seabed, will help scientists date the landforms more accurately and provide a clearer picture of the timing and progression of ice sheet advances and retreats.
The research team also emphasized the broader implications of their findings for our understanding of climate and glacial dynamics. The study highlights the importance of using modern technology and data analysis techniques to uncover buried landforms and refine our understanding of past climate events. By studying ancient ice sheets, scientists can better predict how today’s ice sheets will respond to warming temperatures, which has significant implications for global sea-level rise.
This discovery not only enriches our understanding of the Earth’s climatic history but also underscores the power of new technologies in unraveling the mysteries of our planet’s past. By combining seismic data with detailed geological analysis, researchers are able to unlock information that was previously hidden beneath thick layers of sediment, providing new insights into the behavior of ice sheets, the impact of climate changes, and the evolution of the North Sea region.
The research team behind this groundbreaking discovery includes several notable scientists, including Helge Løseth from Equinor ASA and Harald Brunstad from Aker BP ASA. Their collaboration, alongside the contributions of Dr. Batchelor and Dr. Ottesen, has led to a deeper understanding of the glacial processes that shaped the North Sea and provides new tools for studying past climates and ice sheet dynamics.
Source: Newcastle University