Public Release: 

The Deccan Traps: Double, double magma trouble

American Association for the Advancement of Science

A new study suggests that roughly 65 million years ago, not just one plume of magma, but two, fueled the mass eruption along the Deccan Traps, an event that contributed to one of the greatest extinction events on Earth. The Deccan Traps, located in west-central India, are one of the largest volcanic features on the planet. Yet reconstructing their historic mass eruptions has been difficult, in part because the mantle structure as it was 65 million years ago in this region remains unknown. To compensate for this missing puzzle piece, Petar Glišovi? and Alessandro M. Forte used time-reversed convection modeling, which includes present-day data that captures the three-dimensional (3D) structure of the mantle, and then worked backwards in time to reconstruct changes in the mantle. Their analysis identified a currently active hotspot, Réunion, that was also active 65 million years ago. The researchers found a second upwelling that likely contributed to the ancient eruption that is now associated with the currently active Comores hotspot. The volume of melted mantle that was potentially accessible to the Réunion and Comores hotspots was roughly 40 and 35 million km3, respectively, beginning at around 68 million years, decreasing to near zero around 20 and 40 million years ago, respectively, the authors say.

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