Alaska

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

Published

1 year ago

January 2, 2025

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.

“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.

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.

“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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Alaska

Alaska House advances bill to boost free legal aid for vulnerable Alaskans

Published

7 hours ago

March 2, 2026

Press Room

Alaska House advances bill to boost free legal aid for vulnerable Alaskans

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Alaska

Marten visits are a glimpse into mystery

Published

19 hours ago

March 1, 2026

Press Room

Marten visits are a glimpse into mystery

A trapper fresh out of the Cosna River country in Interior Alaska said he can’t believe how many martens he had caught in a small area so far this winter.

Friends are talking about the house-cat size creatures visiting their wood piles and porches. Could this be a boom in the number of these handsome woodland creatures?

Since the late 1970s, the University of Alaska Fairbanks’ Geophysical Institute has provided this column free in cooperation with the UAF research community. Ned Rozell is a science writer for the Geophysical Institute. Portions of this story appeared in 2000.

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Alaska

Alaska Sports Scoreboard: Feb. 28, 2026

Published

1 day ago

March 1, 2026

Press Room

High school

Basketball

Girls

Monday

Kenai Central 63, Nikiski 33

Colony 68, Grace Christian 46

Tuesday

South 33, East 22

Service 62, Dimond 47

Redington 47, Houston 17

Wasilla 60, Mountain City Christian Academy 44

Kenai Central 54, Homer 27

Bartlett 53, Chugiak 29

Mt. Edgecumbe 59, Sitka 50

Wednesday

Shishmaref 82, Aniguiin 34

Shaktoolik 73, Anthony Andrews 25

Savoonga 61, White Mountain 56

Glennallen 68, Nenana 26

Seward 72, Houston 8

Service 65, South 26

Brevig Mission 65, Koyuk Malimiut 47

Chief Ivan Blunka 67, Manokotak 30

Thursday

White Mountain 76, Anthony Andrews 50

Hoonah 44, Skagway 21

Koyuk Malimiut 53, Aniguiin 51

Nunamiut 74, Kali 17

Glennallen 25, Delta 20

Birchwood Christian 42, Nanwalek 24

Ninilchik 33, Lumen Christi 30

Dimond 59, Chugiak 54

Shaktoolik 57, Savoonga 24

Colony 43, Mountain City Christian 41

Alak 67, Meade River 66

Lathrop 42, West Valley 34

Seward 78, Nikiski 32

Grace Christian 56, Soldotna 41

Kenai Central 56, Houston 10

Wasilla 72, Palmer 27

Bristol Bay 55, Chief Ivan Blunka 30

Nome-Beltz 33, Bethel 24

Scammon Bay 46, Ignatius Beans 28

Aniak 83, Akiachak 45

Shishmaref 53, Brevig Mission 51

Metlakatla 64, Haines 21

Friday

Chief Ivan Blunka 68, Togiak 38

Meade River 80, Nuiqsut Trapper 34

Nunamiut 68, Alak 50

Cook Inlet Academy 33, Birchwood Christian 32

Meade River 71, Kali 46

Kalskag 62, Akiachak 47

Hoonah 39, Kake 37

Soldotna 36, Palmer 23

Delta 54, Valdez 45

Unalakleet 61, Chevak 45

Minto 46, Hutchison 26

West 71, Bartlett 65

Seward 63, Homer 19

North Pole 61, West Valley 25

Newhalen 78, Chief Ivan Blunka 40

Birchwood Christian 43, Nanwalek 28

Bethel 42, Nome-Beltz 35

Aniak 65, Tuluksak 50

Scammon Bay 49, St. Mary’s 38

Monroe Catholic 84, Galena 42

Ketchikan 57, Redington 24

Meade River 69, Alak 62

Fort Yukon 60, Jimmy Huntington 19

Grace Christian 50, Kenai Central 45

Shaktoolik 44, Shishmaref 34

Wrangell 44, Petersburg 31

Saturday

Unalakleet 41, Chevak 37

Meade River 54, Nunamiut 51

Monroe Catholic 68, Galena 32

Newhalen 32, Bristol Bay 26

Cook Inlet Academy 65, Birchwood Christian 32

Soldotna 55, Palmer 42

Nunamiut 48, Meade River 46

Boys

Sunday

SISD 51, Yakutat 18

Monday

Eagle River 54, Birchwood Christian 52

Colony 69, Grace Christian 64

Kenai Central 68, Nikiski 30

Tuesday

Susitna Valley 48, Lumen Christi 46

Dimond 54, Service 47

South 50, East 46

Houston 53, Redington 40

Wasilla 63, Mountain City Christian Academy 50

Kenai Central 74, Homer 47

Chugiak 66, Bartlett 45

Wednesday

SISD 59, Yakutat 17

Shishmaref 85, Savoonga 45

Hydaburg 58, Hoonah 51

Shaktoolik 103, Martin L Olson 49

Skagway 68, Gustavus 24

Davis-Romoth 108, Kobuk 31

Klawock 68, SISD 27

Glennallen 61, Nenana 57

Gambell 46, James C Isabell 31

South 63, Service 60

Seward 81, Houston 73

Bristol Bay 80, Chief Ivan Blunka 61

Mt. Edgecumbe 68, Sitka 59

Scammon Bay 79, Ignatius Beans 34

Brevig Mission 73, Aniguiin 67

Thursday

Savoonga 69, James C Isabell 61

Hoonah 64, Yakutat 45

Alak 88, Meade River 38

Shaktoolik 110, Brevig Mission 30

Chief Ivan Blunka 62, Tanalian 39

Nunamiut 66, Kali 48

Davis-Romoth 91, Buckland 45

Ninilchik 83, Lumen Christi 38

Monroe Catholic 43, North Pole 42

King Cove 57, Bristol Bay 41

Metlakatla 52, Haines 46

Nome-Beltz 62, Bethel 45

Skagway 79, Angoon 30

Birchwood Christian 69, Nanwalek 63

Dimond 60, Chugiak 57

Colony 75, Mountain City Christian Academy 49

Wasilla 66, Palmer 40

Klawock 63, Hydaburg 49

Shishmaref 58, Gambell 47

Grace Christian 63, Soldotna 52

Seward 66, Nikiski 51

Kenai Central 61, Houston 48

Nuiqsut Trapper 64, Alak 51

West Valley 51, Lathrop 44

Akiachak 83, Akiak 64

Scammon Bay 62, Marshall 54

Friday

Hoonah 71, SISD 38

Hydaburg 61, Kake 50

Chief Ivan Blunka 73, Bristol Bay 68

Kali 63, Meade River 45

Nunamiut 80, Nuiqsut Trapper 62

Service 58, East 50

Angoon 61, Hoonah 56

Cook Inlet Academy 73, Birchwood Christian 34

King Cove 75, Newhalen 39

Petersburg 53, Wrangell 20

Skagway 46, Klawock 43

Metlakatla 50, Haines 42

Nome-Beltz 71, Bethel 43

Juneau-Douglas 67, Tri-Valley 45

Wasilla 73, Chugiak 43

West 83, Bartlett 36

Colony 73, Kodiak 32

Delta 62, Valdez 54

West Valley 72, North Pole 46

Palmer 57, Soldotna 47

Nenana 55, Cordova 53

Chief Ivan Blunka 63, Manokotak 48

Scammon Bay 67, St. Mary’s 54

Unalakleet 87, Chevak 64

Shaktoolik 73, Shishmaref 54

Saturday

Unalakleet 95, Chevak 44

Cook Inlet Academy 95, Birchwood Christian 50

South 73, Eagle River 35

Palmer 45, Soldotna 40

• • •

College

Hockey

Friday

UAF 2, UAA 0

Saturday

UAA vs. UAF (Late)

• • •

Women’s basketball

Thursday

UAA 79, Western Oregon 58

Saint Martin’s 99, UAF 59

Saturday

Western Oregon 73, UAF 58

UAA vs. Saint Martin’s (Late)

• • •

Men’s basketball

Thursday

Saint Martin’s 77, UAF 65

UAA 80, Western Oregon 59

Saturday

UAF 82, Western Oregon 74

UAA vs. Saint Martin’s (Late)

• • •

NAHL

Friday

Anchorage Wolverines 5, Chippewa Steel 4

Saturday

Anchorage Wolverines vs. Chippewa Steel (Late)

• • •

2026 Fur Rondy Frostbite Footrace

5K Women

1. Courtney Spann, Anchorage, AK 26:05; 2. Racheal Kerr, Alakanuk, AK 26:07; 3. Anne-Marie Meyer, Yakima, WA 27:06; 4. Riann Anderson, Anchorage, AK 27:09; 5. Nevaeh Dunlap, Anchorage, AK 27:47; 6. Rita McKenzie, Anchorage, AK 27:55; 7. Marta Burke, Anchorage, AK 28:08; 8. Rachel Penney, Eagle River, AK 29:24; 9. Victoria Grant, Eagle River, AK 29:33; 10. Gretchen Klein, Craig, AK 29:36; 11. Penny Wasem, Willow, AK 29:42; 12. Chantel Van Tress, JBER, AK 29:51; 13. Janet Johnston, Anchorage, AK 30:18; 14. Dianna Clemetson, Anchorage, AK 31:33; 15. Sarah Hoepfner, Anchorage, AK 32:02; 16. Ireland Hicks, Seward, AK 33:21; 17. Lilly Schoonover, Seward, AK 33:21; 18. Suzanne Smerjac, Anchorage, AK 33:32; 19. Mindy Perdue, Wasilla, AK 34:12; 20. Oxana Bystrova, Anchorage, AK 34:23; 21. Charlene Canino, Anchorage, AK 34:49; 22. Tami Todd, Wasilla, AK 34:50; 23. Kaiena Tuiloma, Anchorage, AK 34:57; 24. Meg Kurtagh, Anchorage, AK 35:05; 25. Larue Groves, Chugiak, AK 35:13; 26. Rose Van Hemert, Anchorage, AK 36:12; 27. Morgan Daniels, Crestview, FL 36:25; 28. Elle Kauppi, Anchorage, AK 37:31; 29. Miranda Gibson, Wasilla, AK 37:46; 30. Caroline Secoy, JBER, AK 37:46; 31. Jordyn McNeil, Palmer, AK 38:29; 32. Ryan Plant, Palmer, AK 38:30; 33. Samantha Williams, Anchorage, AK 39:00; 34. Wendy Heck, Willow, AK 39:33; 35. Stephanie Kesler, Anchorage, AK 43:29; 36. Denise Wright, Anchorage, AK 43:50; 37. Brie Flores, Anchorage, AK 46:14; 38. Anabell Lewis, Anchorage, AK 46:15; 39. Jessica Lose, Anchorage, AK 46:18; 40. Kaylie Bylsma, Anchorage, AK 46:18; 41. Alicyn Giannakos, Anchorage, AK 46:38; 42. Natasha Henderson, Anchorage, AK 46:39; 43. Shannon Thompson, Anchorage, AK 48:40; 44. Heather Holcomb, Palmer, AK 48:40; 45. Debora Milligan, Iron Mountain, MI 57:36; 46. Rondy McKee, Puerto Vallarta, Jalisco, Mexico, 57:37

5K Men

1. James Miller, Anchorage, AK 18:28; 2. Barefoot Bogey, Woburn, MA 18:37; 3. Keaden Dunlap, Anchorage, AK 19:22; 4. Maximus Tagle-Martinez, JBER, AK 20:03; 5. Gavin Hanks, Eagle River, AK 20:59; 6. Patrick McAnally, Anchorage, AK 21:37; 7. Anthony Gomez, Anchorage, AK 22:37; 8. Christopher Hilliard, JBER, AK 23:20; 9. Terry Schimon, University Place, WA 23:37; 10. Ryan Moldenhauer, Anchorage, AK 24:12; 11. Matthew Haney, Anchorage, AK 24:24; 12. Dan Burke, Anchorage, AK 25:44; 13. Paul Chandanabhumma, Seattle, WA 25:52; 14. Woods Miller, Wasilla, AK 26:51; 15. Bill Grether, Anchorage, AK 27:10; 16. Charles Simmons, Anchorage, AK 27:15; 17. Jacob Cassianni, Anchorage, AK 27:32; 18. John Brewer, Anchorage, AK 28:09; 19. Dustin Whitcomb, Eagle River, AK 28:14; 20. Greg MacDonald, Anchorage, AK 28:28; 21. Kevin Redmond, Anchorage, AK 28:38; 22. Olin Jensen, Anchorage, AK 28:45; 23. Michael Loughlin, Anchorage, AK 29:18; 24. Daryl Schaffer, Anchorage, AK 30:30; 25. Aaron Paul, Anchorage, AK 30:37; 26. Mark Ireland, Anchorage, AK 30:37; 27. Christopher Pineda, Eagle River, AK 30:39; 28. Eric Jostsons, Anchorage, AK 31:07; 29. Justin Fitzgerald, Anchorage, AK 31:36; 30. Steve Lambert, Anchorage, AK 32:09; 31. Justin Atteberry, Anchorage, AK 32:21; 32. Matthew Beardsley, Anchorage, AK 34:07; 33. Caleb Penney, Eagle River, AK 34:21; 34. Evgenii Ivanov, Anchorage, AK 34:22; 35. Eliezer Rivera, Anchorage, AK 35:12; 36. David Massey, Anchorage, AK 35:38; 37. Zachary Todd, Wasilla, AK 35:39; 38. Ed Hills, Anchorage, AK 36:52; 39. Chucky Williams, Anchorage, AK 36:54; 40. Rick Taylor, Wasilla, AK 39:32; 41. Steven Shamburek, Anchorage, AK 43:48; 42. Dave Jones, Anchorage, AK 46:46; 43. Tom Meacham, Anchorage, AK 46:47; 44. Russell Martin, Ventura, CA 47:34; 45. David Martin, Ventura, CA 47:45; 46. Zachary Lounsberry, Palmer, AK 48:41

2.5K Women

1. Kelsey Kramer, Wilmington, NC 13:50; 2. Alannah Dunlap, Anchorage, AK 15:09; 3. Kelsea Johnson, Anchorage, AK 15:45; 4. Kirsten Kling, Anchorage, AK 16:05; 5. Miriam Hayes, Anchorage, AK 16:55; 6. Brianna Slayback, Anchorage, AK 17:04; 7. Haley Hoffman, Alexandria, VA 18:01; 8. Kathryn Hoke, Anchorage, AK 18:32; 9. Rachel Stein, Palmer, AK 18:51; 10. Shayla Harrison, Anchorage, AK 19:29; 11. Danielle Harrison, Anchorage, AK 19:30; 12. Nikki Withers, Tacoma, WA 19:32; 13. Michele Robuck, Anchorage, AK 20:20; 14. Jess Adams, Anchorage, AK 20:20; 15. Ashley Martinez, Miami, FL 20:24; 16. Laura Casanover, Houston, TX 20:31; 17. Adylaine Hacker, Eagle River, AK 21:59; 18. Mary Stutzman, Tallahassee, FL 22:59; 19. Jean Bielawski, Anchorage, AK 23:24; 20. Cheryl Parmelee, Mount Dora, FL 25:45; 21. Ruth Anderson, Anchorage, AK 26:56; 22. Morgan Withers, Tacoma, WA 27:17; 23. Terri Agee, Anchorage, AK 27:31; 24. Chyll Perry, Anchorage, AK 27:35; 25. Denice Withers, Yakima, WA 28:09; 26. Sarah Camacho, Anchorage, AK 28:20; 27. Katheryn Camacho, Anchorage, AK 28:21; 28. Brooke Whitcomb, Eagle River, AK 28:41; 29. Kristine Withers, Tacoma, WA 31:19; 30. Penny Helgeson, Anchorage, AK 33:56; 31. Kimberly Halstead, Eagle River, AK 34:02; 32. Julianna Halstead, Eagle River, AK 34:09

2.5K Men

1. Riley Howard, Anchorage, AK 10:54; 2. Julian Salao, Anchorage, AK 12:26; 3. Mitch Paisker, Anchorage, AK 16:05; 4. Kaden Bartholomew, Anchorage, AK 16:24; 5. Brandon Bartholomew, Anchorage, AK 16:25; 6. Michael Hayes, Anchorage, AK 16:30; 7. Calvin Stein, Anchorage, AK 18:51; 8. Jesse Ackerson, Anchorage, AK 19:42; 9. Clinton Hacker, Eagle River, AK 21:59; 10. Daniel Hjortstorp, Gakona, AK 22:20; 11. Atlas Hjortstorp, Gakona, AK 22:20; 12. Craig Withers, Tacoma, WA 27:18; 13. Jordan Ralph, Tacoma, WA 27:19; 14. Scott King, Anchorage, AK 28:20; 15. Shawn Withers, Yakima, WA 31:18; 16. John Ruthe, Anchorage, AK 35:53

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