A groundbreaking study indicates that the formation of mountains, especially in subduction zones like those found in southern Italy, could be greatly affected by the sinking of a tectonic plate into the Earth’s mantle and the subsequent changes it causes to mantle flow. This presents a contrast to the conventional idea of crustal compression and thickening, thereby broadening our comprehension of the process of mountain creation.
The research, spearheaded by Colorado State University, suggests that the keys to understanding how and why mountains emerge lie deeper than we previously thought.
“Mountain creation is a vital part of the Earth’s behavior,” stated Sean Gallen, the lead author and assistant professor of geosciences at CSU. “This study implies that our understanding of this might not be as comprehensive as we assumed.”
Gallen and his team developed new datasets and methods to leverage landscapes in the reconstruction of extensive mountain formation histories in Southern Italy. The outcomes of this novel approach were what Gallen referred to as “perplexing”.
In subduction zones like Calabria in southern Italy, one tectonic plate slides under another. It has been commonly believed that mountains form in these areas due to the Earth’s crust being compressed and thickened.
The team amalgamated measurements that accounted for both geologically short and long timescales, spanning thousands to tens of millions of years. The landscape provided the missing pieces to this geological puzzle, akin to a “geologic tape recorder”.
“In Southern Italy, the landscape serves as a bridge connecting these varied methodologies that we usually employ,” Gallen explained.
The flat, elevated portions of the landscape on the Italian peninsula’s “toe” correspond to a period when mountain formation was slow, whereas a sudden transition below indicates a fast-paced evolution. These landscape features enabled the researchers to establish a comprehensive, continuous record of rock uplift, the most exhaustive of its kind.
“We anticipated a correlation between the pace at which the plate descends beneath the other plate over time and our rock uplift history, but we didn’t observe this,” Gallen admitted.
The data suggested that the compression and thickening of the crust played a secondary role in the creation of the Calabrian mountains. Instead, the sinking of the lower plate into the Earth’s mantle and the resulting alteration of mantle flow appeared to be the primary factors affecting rock uplift.
“The findings question the standard view of mountain creation, particularly for Southern Italy,” Gallen said. “The process seems to be governed more by factors deeply embedded within the Earth’s system. Such behavior has been predicted in models, but this is potentially the first real-world observation.”
Although Gallen noted that additional data would help confirm their interpretation, existing numerical models support it. Scientists had previously linked mountain height to tectonic plate interactions within the Earth’s plastically flowing mantle, but this study suggests this is the leading process in mountain formation in subduction zones.
“The records we’ve created suggest that deep earth processes seem to have a dominant impact on surface activities,” Gallen explained. “Having worked in the Mediterranean for 15 years, this outcome has fundamentally altered my perspective on these subduction zones.”
Revolutionary, Open Research
The innovative techniques devised for this study signify a leap forward in developing long-term rock uplift histories.
The team assembled a cohesive framework, incorporating standard geomorphology measurements like thermochronology, cosmogenic nuclides, bedrock river profiles, and the records of past sea levels found in marine terraces. This distinctive approach provides a broader timescale than other methods and uses diverse datasets to uniquely inform modelling.
This methodology is particularly useful for active systems where the present landscape provides insights into its past. The further back a system’s activity in geological time, the more challenging it is to confidently reconstruct itshistory.
The software developed for this study, published in Nature Geoscience, is readily accessible for other researchers to utilize. Gallen anticipates that these fresh techniques will stimulate further research and discoveries in different fields.
Reference: “Calabrian forearc uplift paced by slab–mantle interactions during subduction retreat” by Sean F. Gallen, Nikki M. Seymour, Christoph Glotzbach, Daniel F. Stockli and Paul O’Sullivan, 1 June 2023, Nature Geoscience. DOI: 10.1038/s41561-023-01185-4
The National Science Foundation funded the study.
Table of Contents
Frequently Asked Questions (FAQs) about Mountain Formation Theories
What does the new study suggest about mountain formation?
The new study indicates that the formation of mountains, particularly in subduction zones like southern Italy, could be significantly affected by the sinking of a tectonic plate into the Earth’s mantle and the subsequent alteration of mantle flow. This contradicts the conventional understanding that mountain formation is primarily due to the compression and thickening of the Earth’s crust.
Who led the research on mountain formation?
The research was led by Sean Gallen, an assistant professor of geosciences at Colorado State University.
How did the researchers collect their data?
The researchers combined measurements that spanned geologically short and long timescales, from thousands of years to tens of millions of years. They used landscapes to reconstruct extensive histories of mountain formation in southern Italy.
What were the unexpected results of the study?
The unexpected result of the study was that the rate at which the tectonic plate descends did not correlate with their rock uplift history. Instead, the data suggested that the sinking of the lower plate into the Earth’s mantle and the alteration of mantle flow were the primary factors in the creation of the Calabrian mountains.
What do the study’s findings mean for our understanding of mountain building in subduction zones?
The study’s findings suggest that the dominant process in mountain formation in subduction zones might be linked to tectonic plate interactions within the Earth’s plastically flowing mantle. This presents a new understanding that these deep earth processes seem to have a major impact on surface activities.
More about Mountain Formation Theories
- Research Article in Nature Geoscience
- About Subduction Zones
- Information about Mountain Formation
- Sean Gallen’s Research Profile
- About the National Science Foundation
5 comments
i gotta say, pretty cool research. This Sean Gallen guy is onto something. Look forward to more of his work!
Sinking of a tectonic plate into the Earth’s mantle, now thats something. Science never fails to amaze me!!!
Guess our old mountains have more to their story. Makes u wonder what else we don’t know about earth…
whoa, this is mind blowing. Always thought mountains were just about crustal crumpling… deep earth mantle interactions, huh? Learning new stuff everyday!
This is why i love geology!! There’s always something new to discover. Can’t wait to see more research on this!!