Aleutian subduction zone began 56 million years ago, study finds
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An international research team has found that the Aleutian subduction zone, one of Earth's most important plate boundaries, began at least 56 million years ago. The discovery, published in Nature Communications, pushes back the origin of this tectonic feature by millions of years. The finding may help scientists better understand ancient global climate change.
The Discovery
A chain of remote islands and underwater volcanoes between Alaska and Kamchatka, known as the Aleutian Arc, revealed a much older tectonic history than previously known. The Pacific Plate dives beneath the North American Plate along this arc, creating one of the most active subduction zones. The international team showed that this process began at least 56 million years ago, significantly earlier than previous models assumed.
Tectonic Implications
The finding sheds new light on a major reorganization of plate motions that occurred around that time. Earlier models had placed the start of the Aleutian subduction zone much later. The revised timeline aligns with other global tectonic events, suggesting a more interconnected planetary shift.
Climate Connection
The study may also help explain ancient global climate change. Subduction zones influence volcanic activity and carbon dioxide release, which can affect climate over geological timescales. The earlier start of the Aleutian subduction could imply a longer period of volcanic influence on Earth's climate.
Recent Earthquake Swarm
On March 4, 2026, a magnitude 6.4 earthquake struck the remote Aleutian Islands, part of a rapidly developing swarm that began days earlier. The event occurred along one of the most dangerous fault lines on Earth.
What's Next
Researchers plan to investigate whether other subduction zones also have older origins than currently known. It remains unclear how this revised timeline will affect models of past climate and plate tectonics.
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Aleutian subduction zone began 56 million years ago, study finds
