This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Antarctica's glaciers were changing long before satellites, weather stations or cameras captured their transformations, and they left behind clues. Along Marguerite Bay on the western Antarctic Peninsula, ridges of rocks and debris mark former glacier margins.
For decades, scientists lacked direct evidence about when many of these ridges formed. Now, researchers have assigned dates to some of them, filling a key gap in the region's glacier history. The study presents the first direct surface-exposure ages for late-Neoglacial moraines, including Little Ice Age moraines, in Marguerite Bay, the largest bay on the western Antarctic Peninsula.
The scientists dated a moraine on Shoesmith Glacier on Horseshoe Island to 496 ± 79 years ago, placing its formation during the Little Ice Age. Published in Quaternary Science Reviews, these findings offer new physical evidence of how glaciers in this part of Antarctica responded during one of the peninsula's most recent cooling periods. "These ridges resemble ancient boundaries formed by ice.
Determining when the rocks were exposed allows us to map past glacier positions before direct observations. Marguerite Bay was a key missing piece in that historical puzzle," explained professor Attila Çiner of the Eurasia Institute of Earth Sciences at Istanbul Technical University. Scientists have extensive knowledge about the much older retreat of ice from Marguerite Bay after the Last Glacial Maximum, when large ice sheets covered the region.
However, understanding events that occurred over the past several thousand years remains limited. A key period is the Neoglacial, a cooling phase that began around 4,000 years ago and ended roughly 200 years ago. Its later part overlaps with the Little Ice Age, dated from A.D. 1300 to 1850, mainly documented in Northern Hemisphere records.
Previous studies indicate that glaciers advanced in parts of the Antarctic Peninsula during this period, as evidenced by lake and marine sediments, raised beaches, buried mosses and glacial landforms. Researchers have also dated glacier movements around the peninsula in the Little Ice Age. However, Marguerite Bay was still an unexplored area.
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