Connect with us

Alaska

Scientists Finally Solved a 620-Mile Geological Mystery Hidden Beneath Alaska

Published

on

Scientists Finally Solved a 620-Mile Geological Mystery Hidden Beneath Alaska


For decades, geologists have been puzzled by the Denali Fault, a sprawling 620-mile geological feature in Alaska. This massive strike-slip fault system, where tectonic plates slide past each other horizontally, has long hinted at a deeper story—one that shaped North America’s western edge over millions of years. Recent research has finally uncovered the truth behind this mysterious fault, revealing that three distant geological sites, once thought to be separate, were part of a unified suture zone that fused two ancient landmasses into the North American plate.

Led by Sean Regan of the University of Alaska Fairbanks, this study provides groundbreaking insights into the tectonic forces that tore these regions apart over time. Using cutting-edge analysis and a wealth of geological evidence, the team has pieced together a story of massive tectonic shifts, inverted metamorphism, and the power of Earth’s dynamic crust.

A Unified Geological History Revealed

The Denali Fault spans over 1,200 miles, cutting across Alaska and Canada’s Yukon Territory. Its geological complexity has made it a focal point for scientists seeking to understand the processes that shaped North America’s lithosphere. However, the mystery of three specific sites—Clearwater Mountains in Alaska, Kluane Lake in the Yukon, and the Coast Mountains near Juneau—remained unsolved. Were these regions formed independently, or did they share a common origin?

Sean Regan and his team’s research revealed that these sites were once part of a single terminal suture zone, the location where two tectonic plates collided and fused together. This zone, formed between 72 and 56 million years ago, marked the final integration of the Wrangellia Composite Terrane—an ancient oceanic plate—into North America. Over millions of years, tectonic forces caused horizontal movement along the fault, tearing the suture zone apart and scattering its fragments across hundreds of miles.

Advertisement

“Our understanding of lithospheric growth along the western margin of North America is becoming clearer,” Regan explained. “A big part of that is related to reconstructing strike-slip faults such as the Denali Fault.”

The Map Above Shows The Tectonic Plates That Influence Alaska’s Southeastern Fault Systems.
The map above shows the tectonic plates that influence Alaska’s southeastern fault systems. The Pacific Plate is actively subducting (sliding under) the North American Plate at a rate of about 2 inches per year. The Yakutat block (labeled YAK) prevents the Pacific Plate from subducting smoothly, causing the Wrangell Subplate to break off the North American Plate and rotate counterclockwise. The Denali and Totschunda Faults are located along the northeastern edge of the Wrangell Subplate. Image courtesy of the USGS

The Key Role of Inverted Metamorphism

One of the most striking pieces of evidence connecting these sites is the phenomenon of inverted metamorphism. Typically, rocks formed under higher temperatures and pressures are found deeper in the Earth’s crust, while those formed under lower conditions are closer to the surface. However, in these regions, the order is reversed—rocks formed at greater depths are found above those formed under less extreme conditions.

Regan noted: “We showed that each of these three independent inverted metamorphic belts formed at the same time under similar conditions. Not only are they the same age, but they all behaved in a similar fashion.”

By analyzing monazite, a mineral rich in rare earth elements, Regan’s team traced the geological evolution of rocks at each site. Monazite’s unique properties allowed the researchers to track changes in temperature and pressure over time, further confirming the shared history of these regions.

The Denali Fault’s Impact on North America

The Denali Fault’s significance extends beyond its geological intricacies. As a major strike-slip fault, it remains active and capable of generating powerful earthquakes. Understanding its history provides critical insights into the tectonic forces that continue to shape Alaska’s landscape today.

The fault also serves as a natural laboratory for studying plate tectonics. Its role in the accretion of the Wrangellia Composite Terrane illustrates the processes by which distant landmasses are integrated into larger continental plates. These insights are invaluable for reconstructing Earth’s tectonic history and understanding how continents evolve over time.

Advertisement

Decades in the Making

This breakthrough builds on decades of geological research. A 1993 study by scientists at the University of Alberta and the University of British Columbia first suggested similarities between the Denali Fault sites but stopped short of identifying them as a unified structure.

“It was amazing to me that the 1993 paper hadn’t caught more attention back in the day,” Regan remarked. “I had this paper hung up on my wall for the last four years because I thought it was really ahead of its time.”

Regan’s work combines modern techniques with earlier observations to provide a more complete picture of the fault’s history. By piecing together data from multiple regions, the team has connected the dots to reveal the larger tectonic story.

Implications for Geological Science

The Denali Fault study has significant implications for our understanding of plate tectonics and lithospheric growth. By identifying the suture zone that joined the Wrangellia Composite Terrane to North America, the research sheds light on the processes that create and reshape continents.

This work also underscores the importance of collaboration and interdisciplinary research in solving complex geological puzzles. By integrating field observations, mineral analysis, and tectonic reconstructions, Regan and his team have provided a model for studying other fault systems around the world.

Advertisement

“The dots don’t really get connected until you can reconstruct deformation on the Denali Fault,” Regan explained. This study serves as a reminder of the dynamic nature of Earth’s crust and the immense forces at work beneath our feet.

Got a reaction? Share your thoughts in the comments

Enjoyed this article? Subscribe to our free newsletter for engaging stories, exclusive content, and the latest news.



Source link

Advertisement
Continue Reading
Advertisement
Click to comment

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Alaska

Skiers Likely Dead After Avalanche In Alaska – Videos from The Weather Channel

Published

on

Skiers Likely Dead After Avalanche In Alaska – Videos from The Weather Channel




Source link

Continue Reading

Alaska

Alaska political leaders excited by President Trump’s backing of gas pipeline in address to Congress

Published

on

Alaska political leaders excited by President Trump’s backing of gas pipeline in address to Congress


President Donald Trump addresses a joint session of Congress at the Capitol in Washington, Tuesday, March 4, 2025. (AP Photo/Alex Brandon)

Alaska political leaders on Wednesday broadly welcomed President Donald Trump’s remarks to Congress talking up the prospects of the state’s long-sought but faltering natural gas pipeline.

In his speech to a joint session of Congress on Tuesday night, the president said, “It will be truly spectacular. It’s all set to go.”

Trump said South Korea and Japan want to partner and invest “trillions of dollars each” into the “gigantic” pipeline, which has been estimated to cost $44 billion. Japanese news outlets reported Tuesday that no final investment decisions had been made by either nation.

Gov. Mike Dunleavy — who earlier in his political career was skeptical of the pipeline — said that the president’s support “will ensure this massive LNG project is completed, and clean Alaska gas supplies our Asian allies and our Alaskan residents for decades to come.”

Advertisement

U.S. Sen. Dan Sullivan, R-Alaska, said on social media that “the stars are aligned like never before” for the project, which he called “a decades-long energy dream for Alaska.”

In a later post, Sullivan said that he and Dunleavy had urged Trump to give Alaska LNG a “shout out” in his congressional address.

U.S. Sen. Lisa Murkowski, who in recent days has been critical of Trump’s moves to fire federal employees en masse, freeze federal funding and publicly criticize Ukraine’s president, thanked Trump for promoting the pipeline on the national stage.

“This project can provide Alaska and the world with clean and affordable energy for decades to come, while creating thousands of new jobs and generating billions of dollars in new revenues,” Murkowski said.

U.S. Rep. Nick Begich said, “Alaska is poised to play a central role in America’s energy resurgence.”

Advertisement

The decades-long plan to construct an 800-mile pipeline to deliver natural gas from the North Slope for export has stalled in recent years.

In his speech to Congress, Trump said, “My administration is also working on a gigantic natural gas pipeline in Alaska, among the largest in the world, where Japan, South Korea and other nations want to be our partner with investments of trillions of dollars each. It has never been anything like that one. It will be truly spectacular. It’s all set to go. The permitting has gotten.”

The Alaska Gasline Development Corp. — the state agency leading the project — has state and federal permits, but it has not secured financing.

A corporation spokesperson thanked Trump on Wednesday for his “vocal advocacy” for the pipeline.

“There is tremendous momentum behind Alaska LNG from potential offtakers, financiers, and other partners eager to participate in this national energy infrastructure priority,” said Tim Fitzpatrick, an AGDC spokesperson, by email.

Advertisement

Conservative Republican state legislators have been more supportive and optimistic about the project in recent months. The Republican House minority caucus thanked Trump for prioritizing Alaska LNG.

“The proposed LNG project will not only be a huge boost to the economy of Alaska but provide the nation with long term energy security and provide our allies in the global marketplace with needed resources,” said Anchorage GOP Rep. Mia Costello, the House minority leader.

But Alaska state lawmakers have remained broadly skeptical.

The Legislature last year planned to shutter AGDC because it had failed to deliver a pipeline.

”There’s still a lot we need to learn,” said Anchorage Democratic Rep. Donna Mears, chair of the House Energy Committee.

Advertisement

Legislators have questioned who will finance the project, who will buy the gas, whether a connection would be built to deliver gas to Fairbanks, and if the state would need to invest some of its resources to see the pipeline built.

Members of the Senate majority recently estimated that the state had already spent well over $1 billion to advance the pipeline and related projects.

AGDC recently announced that Glenfarne, a New York-based company, in January signed an exclusive agreement with the state agency to lead development of the project.

Palmer Republican Sen. Shelley Hughes said at the time that the outlook for Alaska LNG was “more positive than it’s ever been.”

One factor that has revived interest: Trump’s tariff threats against Japan and South Korea, The New York Times reported.

Advertisement

Japanese news outlets reported on Tuesday that while South Korea and Japan’s governments are continuing to study the project, no final investment decisions have been made.

Prime Minister Shigeru Ishiba told Japan’s parliament on Tuesday that “we will carefully examine its technical possibilities and profitability,” The Japan Times reported.

Larry Persily, an oil and gas analyst and former Alaska deputy commissioner of revenue, said it would be significant if Japan and South Korea signed binding agreements to buy Alaska gas. Pledging to examine the project would be familiar to Alaskans, he said.

“We’ve had decades of that,” he said.

Nick Fulford, an analyst with the Legislature’s oil and gas consultant GaffneyCline, presented to legislative committees on Wednesday about the global gas market and Alaska LNG.

Advertisement

Fulford said Alaska LNG would be a “very expensive project” due to capital costs, but its operating costs would be relatively low. The Alaska project’s vulnerabilities — compared to gas developments in the Middle East — are based on “capital cost inflation,” he said.

GaffneyCline’s forecasts for natural gas demand in coming decades range widely, so do cost estimates for construction of the Alaska pipeline.

Persily said at lower demand levels, Alaska LNG does not seem to be needed in the global market. Wide-ranging cost estimates to complete the project are a cause for concern, he said.

“We’re far away from having a reasonable, confident estimate,” Persily said. “Is it a $44 billion project? Is it $50 billion? Is it $60 billion? We don’t know.”





Source link

Advertisement
Continue Reading

Alaska

Multiple heli-skiers trapped in Alaska’s remote backcountry after avalanche

Published

on

Multiple heli-skiers trapped in Alaska’s remote backcountry after avalanche


Multiple skiers were reported trapped in the Alaska backcountry after being swept up in an avalanche, Alaska State Troopers said Wednesday.

The number of skiers and their conditions were not immediately available.

The slide happened late Tuesday afternoon near the skiing community of Girdwood, located about 40 miles south of Anchorage, Austin McDaniel, a spokesperson for the Alaska State Troopers, said in a text to The Associated Press.

Multiple skiers were reported trapped in the Alaska backcountry after being swept up in an avalanche, Alaska State Troopers said Wednesday. Getty Images

“Troopers received a report of an avalanche that caught multiple individuals who were heliskiing yesterday afternoon near the west fork of 20 Mile River,” McDaniel said. “The company that they were skiing with attempted to recover the skiers but were unable to due to the depth of the snow.”

Advertisement

The size of the avalanche and the depth of the snow was not immediately known.

He said troopers will attempt to reach the site on Wednesday, and may need an aircraft to get to the remote spot well off the Seward Highway.

Girdwood is the skiing capital of Alaska, and home to the Hotel Alyeska, at the base of Mount Alyeska, where people ski or snowboard.

At the top of the mountain is the Seven Glaciers Restaurant, named for its view.

Each winter, 25 to 30 people die in avalanches in the U.S., according to the National Avalanche Center.

Advertisement

One person was killed in an avalanche in central Colorado on Feb. 22. Authorities in Grand County responded to what they described as a skier-triggered avalanche in a steep area known as “The Fingers” above Berthoud Pass.

It was the second reported avalanche in the county that day.


A group of people relaxing along a creek below the Byron Glacier near Portage Lake in Girdwood, Alaska during a record-breaking heatwave
The number of skiers and their conditions is still unknown, according to reports. Getty Images

That avalanche death was the third in Colorado this winter and the second fatality in less than a week in that state, according to the Colorado Avalanche Information Center.

A Crested Butte snowboarder was killed Feb. 20 in a slide west of Silverton.

Elsewhere, three people died in avalanches Feb. 17 — one person near Lake Tahoe and two backcountry skiers in Oregon’s Cascade Mountains.

On Feb. 8, a well-known outdoor guide was caught in an avalanche in Utah and was killed.

Advertisement



Source link

Continue Reading

Trending