Researchers reveal enduring dike flow lasted under 10 years during supereruptions

In a groundbreaking study, researchers from Idaho State University, University of Oregon, University of Wyoming, and Columbia University uncovered important insights related to volcanic eruptions that have occurred within the past 300 million years in North America. Their investigation focused specifically on the Columbia River Basalt Province, a significant geological feature that covers regions of eastern Oregon and Washington, western Idaho, and part of northern Nevada. The area is known for its extensive coverage of volcanic rock formed during enormous supereruptions that happened rapidly, in periods of approximately 2 to 5 million years. To achieve their findings, the researchers employed a new methodology that combined diverse scientific techniques including thermochronology, paleomagnetic data, and stable isotopic analysis. This interdisciplinary approach allowed for more accurate measurements regarding how long segments of dikes within the province were actively transporting magma. Prior to this study, the understanding of volcanic activity related to flood basalts was limited by the merging of individual lava flows, making it difficult to assess the timeline of eruptive periods accurately. The study specifically analyzed a dike that was measured to be around 9 meters (30 feet) wide, providing insight into the dynamics of magma movement in these massive geological events. The results of the analysis indicate that the active flow of magma through the feeder dike occurred for less than 10 years and possibly even less than 2 years. This finding was surprising to researchers because it reveals that the flow rates during these eruptions are extraordinarily high—estimated at 1 to 6.1 km3/day—being orders of magnitude larger than historical eruptions like the 1783 Laki fissure eruption in Iceland. The implications of this rapid flow highlight a stark difference in how supereruptions function compared to more familiar historic volcanic events characterized by prolonged activity over extended timeframes. Overall, the study provides valuable new evidence that aids in the understanding of geological processes related to supereruptions and volcano formation. The revelation of the short-lived active magma flow connects the events to potential underlying geological activities drawing from deep mantle regions, suggesting that the magma responsible for these eruptions might originate from a hot spot in the mantle. As the North American plate moves, this hot spot is now speculated to be located beneath the Yellowstone volcano in northwest Wyoming, hinting at a complex interplay between tectonic activity and volcanic origins.