Researchers reveal a dynamic geologic past for Antarctica’s Transantarctic Mountains, uncovering ancient mountain-building and glaciation events hidden beneath the ice.
A new study led by University of Wisconsin-Oshkosh geologist Timothy Paulsen and University of Colorado Boulder thermochronologist Jeff Benowitz offers fresh insights into the geologic history of the Transantarctic Mountains. Their research sheds light on the evolution of the ancient landscapes hidden beneath Antarctica’s massive ice sheets.
The team analyzed the chemistry of mineral grains commonly found in igneous rocks, such as granite, from the Transantarctic Mountains. Other scientists from the University of Arizona, Saint Louis University, The Ohio State University, and the University of Alaska Fairbanks also contributed to the research.
Their study was published in Earth and Planetary Science Letters.
The “Great Antarctic Horst”
“Early exploration of the Antarctic continent revealed a surprising result, a 3500 km long mountain range with peaks over 4500 m crossing the Antarctic continental interior,” said Paulsen, the lead author on the paper. “This range was known as the ‘great Antarctic horst’ and is recognized today as the Transantarctic Mountains. These mountains currently restrict the East Antarctic ice sheet as it flows from East Antarctica to low elevations in the Ross Sea.”
Yet there are significant questions about the past uplift history of the Transantarctic Mountains, as well as the rugged under-ice topography of Antarctica, which may have influenced the growth and behavior of ice sheets over time.
Unveiling Antarctica’s Ancient Bedrock
“The Antarctic ice sheets blanket and mask the bedrock geology of Antarctica,” said Benowitz, a coauthor on the paper. “The time-temperature evolution of Transantarctic basement rocks can provide important clues for understanding the development of the under-ice bedrock topography of Antarctica, especially ancient landscapes that predated the Cenozoic rise of the Transantarctic Mountains and how these older mountains possibly influenced glacial cycles.”
The researchers’ findings, based on an analysis of an exceptionally large data set from igneous rocks recovered from the Transantarctic Mountains, may signify a much more dynamic Antarctic landscape history than previously recognized, including added support for a glacial period around ~300 million years ago.
“Our new results suggest Transantarctic Mountain basement rocks experienced several punctuated mountain-building and erosion events, creating surfaces along which ancient rocks are missing,” Paulsen said. “These events are curiously associated with major plate tectonic changes along the margins of Antarctica. Based on our analyses, the older geologic history of the continent may have profoundly shaped the patterns of the modern landscape, which likely influenced cycles of glacial advance and retreat, and perhaps evolutionary steps in Earth’s global ocean-atmosphere system.”
Reference: “Antarctic Phanerozoic landscape evolution along the Transantarctic basin from thermochronology” by Timothy Paulsen, Jeffrey Benowitz, Stuart Thomson, John Encarnación, Anne Grunow, Paul Layer and Maddie Young, 21 May 2025, Earth and Planetary Science Letters.
DOI: 10.1016/j.epsl.2025.119445
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