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

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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.

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“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.

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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.

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“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.

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Opinion: As he starts his final two years, Alaska Gov. Dunleavy’s mixed legacy

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Opinion: As he starts his final two years, Alaska Gov. Dunleavy’s mixed legacy


Gov. Mike Dunleavy is in the last two years of his two terms as governor. He must be thinking of his legacy, of what he accomplished.

It’s time for all of us to give the governor a report card, too. Like a student in the final semester, it’s not too late to bring up the grade.

What’s on the legacy ledger so far? I see three negatives, one partly corrected. This was the governor’s disastrous first-term budget cuts, when he took a meat ax to state programs and the University of Alaska.

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I think the new governor got bad advice. He changed out his advisers and reversed course on many of the cuts. He is now supporting the university, for example, in restoring its funding. But the damage was done.

Two other blemishes are still on Dunleavy’s ledger. One is his refusal, so far, to increase school funding to offset several years of inflation. He has agreed to one-time increments of money, but that doesn’t count. We can’t hire teachers with one-time money.

A second stain on the ledger is Dunleavy’s ambivalence toward repairing public-sector pensions. There is an exodus of skilled state and local government workers who are recruited to other states with better benefits and salaries.

But the governor has some positives, too. One is his record on energy. He has strongly supported innovations, alternative energy and conservation. His annual conferences on energy — another one is planned in June — have attracted a lot of attention.

I’m impressed with a focused drive in Dunleavy’s administration to establish carbon sequestration, both forest-based and by underground injection and storage. These will help the planet by storing carbon dioxide, a leading cause of climate change. They also give Alaska industries a way to burnish their image among major financiers who score their loans for management of carbon emissions.

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The carbon programs are complex and it took a sustained, two-year push by the governor and his Department of Natural Resources to get buy-in from the Legislature.

Another plus for Dunleavy: The streamlining, long-delayed, of regulation of long-distance power transmission. That will make larger regional renewable energy projects possible because new power can be moved through the grid with less delay.

This took another two-year push to get the Legislature’s buy-in, and this time the governor’s office led the effort along with the Alaska Energy Authority. Getting Alaska’s utilities to work together was an accomplishment. It was like herding cats.

So far on the report card: Two positives and three negatives, one partly repaired (the big budget cut).

There’s still time for Dunleavy to repair his record on school funding and pensions. Another legislative session looms. However, I see potential for a third positive for the governor in his advocacy of food security and agriculture. Dunleavy has always talked about food security, and this year he has a proposal for a new state Department of Agriculture.

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This has prompted some head-scratching because many Alaskans don’t even know we have farms and many children don’t understand where food really comes from.

The governor talks about food security, but I think of agriculture for its economic development potential. There’s business here, and jobs.

We now have a small agriculture industry that’s highly regional, in the Mat-Su, Kenai Peninsula and Interior Alaska, and it really springs to life in summer. Farmers are the ultimate entrepreneurs as the vibrant summer farmers markets in many parts of the state demonstrate.

Can we build on the energy and entrepreneurship Alaskans show in those farmers markets? They prove Alaskans will buy locally made products and pay a premium for fresh and quality food.

Consumers show this nationwide, too. I think Dunleavy is on to something.

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What could a Department of Agriculture do that our present Division of Agriculture, now part of the Department of Natural Resources, doesn’t do? The division, which is based in Palmer, does a lot now. Its Plant Materials Center does research on crops and inspects for the quality of food products. The division also administers loans for farmers.

But the Department of Natural Resources has a lot of other things on its plate. DNR looks after oil and gas, mining, forest firefighting and caretaking of Alaska’s 100 million acres of state lands.

Plucking a division out of a department with a lot on its plate can have benefits. We saw this when the governor reorganized the former Department of Health and Social Services into two new departments. The new Department of Health was able to focus attention on public health.

Raising the profile for farming (this includes ocean farming, or mariculture) has benefits in focusing attention in the Legislature. I saw this in the last legislative session when several worthy farm-related bills didn’t get the attention they deserved.

“Food security” is a nice goal, but is it just a sound-bite? Some worry about this because Dunleavy has talked agriculture before and not much seems to happen. Just creating a new state department won’t change anything without specific plans, and budgets.

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I have a list of things the governor could do. It starts with making sure food banks and food assistance have support. Dunleavy could also press school districts to buy healthy local food rather than the processed stuff kids are fed.

Also on my list: Jaw-boning managers of big grocery chains so they’ll give locally grown products more shelf space over their own corporate food brands. Alaskans will buy local, but they need to see the products on store shelves.

I remember when we had dairy farms in the Mat-Su and Interior. Juneau once had its own dairy. Alaska-made milk was in the stores. Now we have corporate dairies in the Pacific Northwest supplying our milk. The worst part of this is that imported milk often goes sour, even before the “sell by” date on the milk carton.

We must do better if we really want food security.

Tim Bradner is publisher of the Alaska Economic Report and Alaska Legislative Digest.

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The views expressed here are the writer’s and are not necessarily endorsed by the Anchorage Daily News, which welcomes a broad range of viewpoints. To submit a piece for consideration, email commentary(at)adn.com. Send submissions shorter than 200 words to letters@adn.com or click here to submit via any web browser. Read our full guidelines for letters and commentaries here.





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Warm up heading toward Alaska

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Warm up heading toward Alaska


ANCHORAGE, Alaska (KTUU) – After days of intense cold and sometimes dangerous wind chills, a warm-up is on the way for Alaska by early next week. Anchorage will go from daytime highs in the teens to highs in the mid-30s and a chance of rain and snow.

While the Interior will warm up, it probably won’t get above freezing anytime soon. Expect temperatures to warm to near 20 degrees by Tuesday of next week.

Before then the clear skies mean better chances to view the Aurora. The aurora forecast shows times for Friday and Saturday with KP index of 4 to 5, meaning active aurora. Don’t forget! We love to see your best photos and videos (or the aurora or just our beautiful state). Upload them at Alaska’s News Source.com.

See a spelling or grammar error? Report it to web@ktuu.com

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In Alaska, air travel is a fact of life. But what happens when someone dies on a plane?

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In Alaska, air travel is a fact of life. But what happens when someone dies on a plane?


It was just before Thanksgiving two years ago that Jim Haugom died on a flight to Alaska.

Haugom and his wife, Patty, were returning from a family visit on Oahu and looking forward to the holidays at home.

Jim Haugom got up to use the lavatory about 45 minutes out of Anchorage on the early-morning flight. He lost consciousness and couldn’t be revived, despite the immediate efforts of the flight crew and their fellow passengers.

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Two years later, Patty Haugom still expresses only gratitude for the compassion and care she experienced on one of the worst days of her life.

Flight attendants and medical professionals she’d never met before tried to save her husband. Strangers prayed with her. Responders on the ground guided her to a private space to grieve.

“The crew was heroic,” Haugom said. “In that little tiny area … there was four flight attendants and passengers in there, and they had the right equipment. They were on top of it. They never stopped. Even as we landed, they were still working on him.”

In a geographically isolated state like Alaska where flying is often a necessity, midair medical emergencies are a stark reminder of how vulnerable air travelers can be.

A death on a plane brings into sharp focus the snap decisions facing the flight crew and medical professionals who step up to help, the trauma inflicted on other passengers in such a cramped space — and the bond they all share around someone’s last moments.

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“It’s hard for everybody involved: family, crew, passengers,” said Seth Heiple, a flight attendant and union safety chair of the Association of Flight Attendants-CWA.

Midair rarities

The odds of someone dying on a plane are extremely low, even as medical emergencies have become more common with billions of passengers flying every year and “an increasing aging of air travelers” with significant health issues, according to a 2021 study published in The American Journal of Emergency Medicine.

Since 2022, there have been an average of two midair fatalities a year involving flights landing in Anchorage, according to Cpl. Daniel Harmeling, with the Anchorage Airport Police & Fire Department. That statistic reflects scheduled flights as well as those diverted due to in-flight emergencies.

The 2021 study found there were 0.21 deaths on planes for every million passengers.

Don Young, Alaska’s lone United States representative for years and the longest-serving Republican member of Congress in history, was one of those rare cases.

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Young — seated with his wife, Anne — died on a flight from Los Angeles to Seattle in March 2022 after losing consciousness as the plane descended into Seattle. Medics on the ground were unable to revive him. Young’s communications director, Zack Brown, was also on the plane.

“Felt like the longest day of my life and I can’t believe it’s been an entire year,” Brown posted on X a year later, in March 2023. “Always grateful for our Alaska Airlines crew and everyone who helped me get my boss’s remains & Mrs. Young back to DC. There was no playbook for what happened, but I had an amazing support system.”

Coming home

Patty Haugom said there was little indication of anything wrong with her husband’s health before they got on that 2022 flight. He’d been falling a little more than usual, she realized later.

The Haugoms moved to Alaska from South Dakota in 1971. Haugom, 76 when he died, worked at the Mat-Su Valley Frontiersman before moving to a lineman position at Matanuska Telephone Association. He retired by 2007, a loving grandfather, yard-proud gardener and woodworker who could fix anything.

The Haugoms have six children, including a son who lives on Oahu. On that 2022 trip, other family members flew in from Alaska. They all spent just over a week together.

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The long flight over the North Pacific Ocean back to Anchorage was nearing its end when Jim Haugom rose to use the restroom. Their daughter, her husband and their children were seated farther back.

Patty Haugom got the attention of a flight attendant when she realized he’d been gone too long. When the attendant unlocked the lavatory door, Haugom could see immediately that something was wrong. Her husband was slumped over, unconscious.

The flight attendant got on the intercom to ask for help transferring the big man from the confined space.

“She announced that they had a medical emergency, and she needed three strong guys,” Patty Haugom recalled. “There was three guys up there, got him out on the floor, and right across the aisle from us was a heart specialist.”

As the lights remained low, a flurry of activity surrounded her husband. Someone started CPR compressions as passengers helped Patty Haugom shield the scene with blankets.

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“I remember standing in that archway, holding my shirt open, trying to see if I could get people not to see,” she said. “I was just in shock.”

‘It leaves a mark’

Flight attendants are trained to handle such medical emergencies, according to Heiple.

There are recurrent trainings every year and CPR training twice a year, he said. Aircraft carry AEDs — defibrillators that can deliver a shock to restore regular heart rhythm — and medical kits that include everything from blood-pressure cuffs and bandages to controlled substances that require a doctor’s permission to open.

If a passenger requires medical help, a flight crew will generally notify the pilot and call for assistance from any medical professionals on board, Heiple said. Airlines contract with third parties such as MedAire to provide real-time advice from nurses and doctors on the ground.

If someone is experiencing a cardiac arrest or stroke, the crew will continue life-saving procedures until a medical professional makes an official death pronouncement, Heiple said. Flight attendants will try to move passengers, especially those with children, who are seated near someone having a medical emergency.

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Heiple has helped with in-flight CPR three times in his career. The people doing compressions will trade off; the procedure is exhausting as well as emotionally draining. Sometimes CPR may continue for hours.

“It can be really traumatic for the crews,” he said. “In fact, I’m getting a little emotional talking about it.”

Flight crews who work on a flight where a death occurs get seven days of paid leave, according to Heiple. They will usually receive a confidential mental health debriefing session.

“Even years later, it leaves a mark,” he said.

Compassion and respect

The family doesn’t know exactly what caused Jim Haugom’s medical emergency, but whatever it was happened very fast, his wife said.

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At the time, she could barely process what was happening. As her daughter started texting family members that Haugom was receiving CPR on the plane, a passenger sitting in the seat in front of Patty Haugom and her daughter turned around.

She held Haugom’s hand and asked, “Do you want us to pray with you?”

Haugom, who attends St. Michael Catholic Church in Palmer, found solace in that small gesture.

“It just meant a lot to me and my daughter,” she said.

Once the plane landed, Haugom accompanied her husband as medics moved him into the airport, where he was pronounced dead. A police officer escorted her. She and her daughter were allowed to stay with Haugom’s body for as long as they wanted.

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Her daughter has stayed in touch with the crew from that flight since.

“The passengers were wonderful, they really were. And everybody was just so respectful,” Patty Haugom said. “Flight crews put up with so much these days. Those people deserve every ounce of credit they can get.”

• • •





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