By Clarence Oxford
Los Angeles CA (SPX) March 06, 2025
Channels carved by rivers, lava and ice exhibit sinuous, meandering patterns, but a new study from The University of Texas at Austin has identified a key difference in the way rivers curve compared to volcanic and ice-carved channels. This discovery could provide a new method for determining the origins of planetary channels where direct observation is not possible.
While the specific mechanisms that shape these bends remain unclear, previous models suggest a relationship between fluid flow and channel topography. In rivers, centrifugal force causes water to move faster along outer bends while slowing down along inner edges. This process erodes the outer banks and deposits sediment on the inner banks, progressively increasing the river’s curvature.
In contrast, channels formed by lava or ice are shaped by thermal erosion, without sediment deposition. As a result, only the outer bends undergo significant changes, leading to smaller, less pronounced bends compared to river channels.
“This distinction creates a great natural experiment to see if the shape, or size, of river bends is different from that of volcanic or ice channels,” said Tim Goudge, an assistant professor in the Jackson School’s Department of Earth and Planetary Sciences and a co-author of the study.
The study, published in Geology, suggests that this differentiation could serve as a tool for identifying the origins of meandering channels on extraterrestrial bodies. Scientists studying planetary surfaces often lack the ability to directly measure or sample channels, making remote diagnostic techniques valuable.
Lead researcher Juan Vazquez, a 2024 graduate of the Jackson School, has analyzed thousands of river and ice channels on Earth, as well as volcanic channels on the Moon. Initially mistaking an anomaly in the data for an error, he soon realized that river bends exhibited more exaggerated curvature than other channels.
“It wasn’t until the parameters for the code that we had set for volcanic channels on the Moon kept failing for rivers on Earth that we realized, ‘Oh, this isn’t a glitch in the code. This is an intrinsically different amplitude,’” Vazquez said.
Further analysis revealed that volcanic and ice channels tend to exhibit a higher frequency of downstream-biased bends compared to rivers.
On Earth, geologists can determine the origin of a channel by examining the presence of fluids or identifying geological markers left by past flows. However, on distant planetary bodies like Titan — where flows of ethane and methane carve channels through water ice — scientists struggle to determine whether such formations result from sediment transport or thermal erosion. A similar challenge exists on Mars, where both ancient rivers and volcanic activity shaped the landscape billions of years ago.
“There are these winding channels on the sides of Martian volcanoes. Some people have interpreted them as volcanic channels, and some people have interpreted them as rivers that formed when perhaps the snowpack on top of the volcano melted,” Goudge said. “We’re saying that because the curves of volcanic channels are so distinct, you can measure these channels to find out.”
However, Goudge cautioned that while the study provides valuable insights, it should not be used as an absolute classification system. Individual channels can vary significantly, and more research is needed to refine the method.
“But I think it has the potential to be that way if we understand it better,” she added.
Doctoral student Mariel Nelson of the Jackson School contributed to the study as a co-author.
