A University of Wisconsin Oshkosh geologist and a University of Colorado Boulder thermochronologist have uncovered critical insights into Antarctica’s evolution by employing complex chemical analysis of the bedrock beneath its ice sheets.
The findings include new insights into the evolution of a hidden 3,500-kilometer-long mountain range named the Transantarctic Mountains. The researchers believe that studying the history and dynamics of Antarctica’s ancient past could play a crucial role in understanding the climate dynamics of Earth’s most remote continent.
In Antarctica, Studying an Ancient Lost Landscape Means Getting Creative
“The Antarctic ice sheets blanket and mask the bedrock geology of Antarctica,” University of Colorado Boulder thermochronologist Jeff Benowitz, a coauthor on the paper detailing their research, explained.
For Benowitz and the paper’s lead author, University of Wisconsin-Oshkosh geologist Timothy Paulsen, this meant trying to understand the evolution of one of the most enigmatic and largest hidden mountain ranges on Earth, according to a statement highlighting the research team’s findings.
“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,” Paulsen explained. “This range was known as the ‘great Antarctic horst’ and is recognized today as the Transantarctic Mountains.”
Although this ancient lost landscape remains hidden from view, the researchers say it is critical to the continent’s ecosystem. For example, the Transantarctic Mountains restrict the East Antarctic ice sheet as it flows from East Antarctica to lower elevations within the Ross Sea. Still, the research team said scientists have had a hard time understanding the “rugged under-ice topography of Antarctica” and how these ancient lost landscapes could have shaped the growth and behavior of the ice sheets over long periods of time.
Chemical Analysis of the Transantarctic Mountains
Since directly accessing the mountain range wasn’t an option, the researchers collected rock samples known to come from the Transantarctic Mountains and examined their internal chemistry. According to Benowitz, they hoped these tests could uncover several key insights into the ancient lost world, including how it evolved over various periods and how temperature changes affected that evolution.
“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 UC Boulder thermochronologist explained.
Following the tests, the team analyzed what they described as an “exceptionally large data set from igneous rocks recovered from the Transantarctic Mountains.” As hoped, that analysis found compelling evidence of a previous glacial period in Antarctica around 300 million years ago. The chemical breakdown of igneous rocks also showed evidence for changes over time, creating a “much more dynamic Antarctic landscape history than previously recognized.”
“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.”
Geologic History May Have “Profoundly Shaped the Patterns of the Modern Landscape”
While further research may answer even more questions about Antarctica, the team believes their analysis showed that the evolution of that landscape, including the Transantarctic Mountains, could be vital to understanding the continent’s modern environment.
“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,” Paulsen concluded.
Christopher Plain is a Science Fiction and Fantasy novelist and Head Science Writer at The Debrief. Follow and connect with him on X, learn about his books at plainfiction.com, or email him directly at christopher@thedebrief.org.