船载勘测捕捉地幔柱的脉动节拍

Seismic imaging and drilling cruises bolster a controversial explanation for ancient mass extinctions PAUL VOOSEN The textbook view of mantle plumes—the long-lived columns of hot rock that rise from deep in the planet—makes them seem like giant blowtorches, steadily searing the crust from below. But new studies of the sea floor around Iceland are pointing to a long-debated alternative: that plumes are actually more like blobs rising in a lava lamp, delivering intermittent pulses of heat. The studies could also help explain an abiding puzzle. Mantle plumes are thought to have caused several of the planet’s mass extinctions by driving massive volcanic eruptions that belched carbon dioxide and other greenhouse gases, disrupting the climate. …