News — DALLAS () – A study published in the challenges whether glaciers are eroding mountains faster now than in the past.
According to global research, glacier erosion has increased significantly over the past 5 million years. Scientists have typically attributed this acceleration to the greater climate fluctuations that have defined the recent Cenozoic era—the period encompassing both the Ice Age and our current warming, post-glacial phase.
These more extreme shifts between cold and warm conditions may have intensified glacial activity and their resulting impact on landscapes. To determine if glaciers are eroding mountains faster now than in the past, SMU researchers traveled to Lake Argentino in Patagonia. They found that glaciers move a lot of rock over time, with periods of intense erosion followed by timespans of little activity.
By studying these mechanisms, scientists hope to understand the interaction between climate and tectonic plate movement, which could help predict landscapes' response to future climate shifts.
“Glaciers are sensitive to climate and are also counterbalancing the mountain building of tectonic uplifts,” said SMU seismologist . “While the Earth’s crust pushes mountains up from below, glaciers wear them down from above. How glaciers move material across the Earth’s surface affects many things, from river systems to coastal environments.”
Anastasia Fedotova, who completed her Ph.D. in Geophysics and Seismology at SMU, is the lead author and currently works at Geospatial Consulting Group International.
Connection Between Lake Argentino and Glaciers
Lake Argentino was created by glacial melt. During the Ice Age, the Argentino Glacier blanketed the area where the lake now sits. Scientists track its history by studying moraines, distinctive ridges of rock and debris that form at glacier edges.
Moraines serve as natural time markers, revealing not only a glacier's past boundaries but also the timing and patterns of its retreat as warmer periods trigger melting. Like geological footprints preserved in the landscape, moraines tell researchers how Lake Argentino emerged as the ice gradually receded.
The newly formed lake became a collection basin, capturing sediments, rocks and debris trapped within the melting ice or scraped from the surrounding mountains. This process built up layers on the lake’s bed, creating a detailed record of past climate conditions. Lake Argentino now contains specimens of glaciers that have shifted over the past 20,000 years.
To study the layers, SMU researchers used seismic imaging technology to see beneath the lake floor. They mapped five layers of sediments deposited by the Argentino Glacier and its modern remnant, the Upsala Glacier. Each layer matched a different historical glacial cycle, showing patterns that provided a greater understanding of how the glaciers shaped mountains.
Underwater ridges visible in the seismic data were identified and compared to dated moraines (rock piles left by glaciers) found on land. This comparison helped the researchers determine the ages of different sediment layers beneath the lake. The team collected and examined samples from the lake's bottom to further analyze these layers.
Glacial Erosion Happens in Episodes
The researchers used a dated record to calculate erosion rates during specific time windows throughout the 20,000-year period. When they compared erosion rates across similar time intervals – for example, comparing 100-year periods from different times in history – they found a consistent pattern: glaciers erode mountains in bursts regardless of the time period.
This key finding demonstrated that glaciers weren't actually eroding faster in modern times than they did thousands of years ago - the pattern of erosion has remained consistent, but happens in bursts of activity separated by quieter periods. The stop-and-go pattern explains why erosion rates appear different when measured over decades versus millennia – not because glaciers behaved differently in the past, but because longer measurements capture intense and quiet phases.
"These findings will help other scientists interpret climate records preserved in glacial deposits worldwide and also lend to us better-predicting landscape evolution," said Magnani.
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