AlaskaITG 1735882401181

'620-mile fault mystery': Scientists uncover tectonic secrets beneath Alaska’s terrain

Produced by: Mohsin Shaikh

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Alaska 1ITG 1735882523203

Fault enigma

Beneath Alaska lies the Denali Fault, a 620-mile mystery that has puzzled geologists for decades, now revealed as the key to ancient tectonic events.

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Unified history

Sean Regan’s research uncovers how three regions—Clearwater Mountains, Kluane Lake, and Coast Mountains—once formed a single suture zone on North America’s plate.

Credit: Wikimedia Commons

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Inverted puzzle

Inverted metamorphism in these regions reveals rocks formed at great depths now lie above shallower ones, offering clues to tectonic activity.

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Plate fusion

The Wrangellia Composite Terrane, an ancient oceanic plate, fused with North America 72 million years ago, driven by massive tectonic forces.

Credit: Wikimedia Commons

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Dynamic shifts

Over millions of years, strike-slip movements along the Denali Fault tore the unified suture zone apart, scattering fragments across hundreds of miles.

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Critical insights

Monazite analysis helped Regan’s team trace temperature and pressure changes, confirming a shared history of these regions under identical conditions.

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Seismic risks

The Denali Fault remains active today, capable of triggering powerful earthquakes, shaping Alaska’s rugged landscape.

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Decades untangled

Building on a 1993 study, Regan’s findings combine modern techniques and historical data to reconstruct the Denali Fault’s tectonic story.

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Global lessons

This study provides a model for understanding how continents evolve and offers a framework for studying similar fault systems worldwide.

Credit: Wikimedia Commons