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On the deep-mantle origin of the Deccan Traps

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Science  10 Feb 2017:
Vol. 355, Issue 6325, pp. 613-616
DOI: 10.1126/science.aah4390

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Double trouble for the Deccan Traps

The continental flood basalts in India known as the Deccan Traps formed from a massive outpouring of lava around the time that dinosaurs went extinct. The event dramatically reshaped the landscape and altered the climate. Glišović and Forte used time-reversed convection modeling to reconstruct the origin of this giant magmatic event. They found that two different deep mantle hotspots joined forces about 65 million years ago to produce one of the largest volcanic features on Earth.

Science, this issue p. 613

Abstract

The Deccan Traps in west-central India constitute one of Earth’s largest continental flood basalt provinces, whose eruption played a role in the Cretaceous-Paleogene extinction event. The unknown mantle structure under the Indian Ocean at the start of the Cenozoic presents a challenge for connecting the event to a deep mantle origin. We used a back-and-forth iterative method for time-reversed convection modeling, which incorporates tomography-based, present-day mantle heterogeneity to reconstruct mantle structure at the start of the Cenozoic. We show a very low-density, deep-seated upwelling that ascends beneath the Réunion hot spot at the time of the Deccan eruptions. We found a second active upwelling below the Comores hot spot that likely contributed to the region of partial melt feeding the massive eruption.

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