Produced by: Mohsin Shaikh
Martite, a rusted form of magnetite, preserves the moment rocks were exposed to surface air and water—becoming nature’s forensic timestamp for deep time events.
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Using microscopic textures and (U-Th)/He thermochronometry, scientists can now date oxidation events that occurred over a billion years ago with stunning precision.
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These rusted rocks tell when buried formations reached Earth's surface. It’s the first method that directly traces near-surface exposure in deep geological history.
Martite dating cracks open Earth’s “missing chapters”—massive erosion gaps where rock layers spanning billions of years vanished from the record.
New data from Colorado show parts of the Great Unconformity may have formed 1.4 billion years ago—far earlier than theories tied to the Snowball Earth glaciation.
Though martite looks like its parent magnetite, inside it holds hematite micro-crystals—the key to unlocking geochemical histories masked for eons.
Credit: Jordan Jensen, USU
Electron backscatter imaging reveals martite’s basket-weave patterns—clues that survived burial, uplift, and tectonic chaos for a billion years or more.
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Martite is common in crustal rocks worldwide, making this method a breakthrough tool for dating erosion, weathering, and tectonic surface events everywhere.
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These ancient iron grains don’t just record when rocks surfaced—they’re rewriting Earth’s tectonic timeline and revealing how continents evolved.