Antarctica is characterized by reaching the limits in everything, it is the coldest and driest of the continents, the most windy speed, as well as being the most isolated continent on earth, but beneath the surface of that frozen continent lies many secrets that may reveal the past and future of the region, one of which is the giant landslides that occurred millions of years ago and caused deep scars in the continental slope.
But what caused these landslides? And could it happen again in the future? What will be the consequences of their recurrence? These are the questions that an international team of scientists led by the University of Plymouth began to search for an answer to, by digging on the seabed and collecting sediment samples, and the team was able to identify 3 major landslides.
The results of their study, published in the journal Nature Communications on May 18, revealed that these landslides were caused by climate change in the past, when Antarctica was warmer and the ice sheets were smaller than they are today. The team also suggests that ongoing global warming could increase the risk of similar events in the future.
Landslides are important not only in their size, but also in their potential impact, as they can generate powerful tsunamis that travel across the Southern Ocean, reaching the coasts of South America, New Zealand and Southeast Asia, and disrupt marine ecosystems and ocean circulation patterns.
According to a press release on the Eurekalert website, the team first discovered landslides during the Odyssea's exploration voyage in the eastern Ross Sea in 2017, where the team visited the area as part of an International Ocean Discovery Program expedition, collecting sediment samples from areas hundreds of meters below the seabed.
By analyzing these samples, the team found microscopic fossils that contributed to a picture of the region's climate state millions of years ago, and how it created vulnerable layers in the depths of the Ross Sea that in turn led to landslides.
The key to understanding the phenomenon of landslides lies in understanding the composition of the sediments that cause them, as scientists have found that these deposits consist of alternating layers of diatomic clay deposits and marine snow deposits, those deposits are a mixture of mud, sand and gravel that is deposited by icebergs or meltwater, when the ice sheets are large and close to the coast.
The key to understanding the phenomenon of landslides lies in understanding the composition of sediments caused by Shutterstock.
Rapid climate changes millions of years ago
These layers reflect changes in climate dynamics and ice sheets that occurred in Antarctica over millions of years during warm periods, 2.6 to 23 million years ago, as Antarctica was more abundant in flora and wildlife on land and in the ocean, all the way to ice epochs when Antarctica became a frozen desert with huge ice layers covering most of the continent and extending into the sea.
Scientists have discovered that these climate changes have also affected the stability of the continental slope, due to the weakening, dense and high water content of diatomic deposits, as these deposits form weak layers that can slide along the slope when exposed to external forces, such as earthquakes or ice accumulation.
Scientists believe these vulnerable layers were likely to have resulted from the warm climate in the past, when they accumulated on the seabed. It was then stimulated by seismic activity associated with ice recycling, which is the rebound of the crust after it has been reduced by ice sheets. This process creates cracks and cracks that can activate landslides and landslides along weak layers.
The results of this study are important for assessing the probability of geographic danger to the edges of Antarctica (Shutterstock).
Future Risk Assessment
The results of this study are important because they help us assess the future geohazard probabilities of Antarctica's margins, as global warming continues to melt ice sheets and raise sea levels, ice changes may lead to increased seismic activity along the continental slope, leading to more subsea landslides. Furthermore, warm water may erode sediment or increase its water level, reducing its strength and stability.
Scientists warn that these factors could create certain backlash cycles that reinforce landslides and generate high-risk tsunamis in an increasingly warming world. Scientists recommend further research and monitoring to better understand the mechanisms and consequences of subsea landslides in Antarctica and other polar regions.