Share
The extrusion of fresh ocean crust at midocean ridges began to slacken 15 million years ago, perhaps cooling the planet. geogphotos/Alamy Stock Photo
Slowdown in plate tectonics may have led to Earth’s ice sheets
Dec. 22, 2020 , 11:05 AM
In seafloor trenches around the world, slabs of old ocean crust fall in slow motion into the mantle, while fresh slabs are built at midocean ridges, where magma emerges at the seams between separating tectonic plates. The engine is relentless but maybe not so steady: Beginning about 15 million years ago, in the late Miocene epoch, ocean crust production declined by one-third over 10 million years to a slow pace that pretty much continues to today, says Colleen Dalton, a geophysicist at Brown University who presented the work this month at a virtual meeting of the American Geophysical Union. “It’s a global phenomenon.”
Суд в Уссурийске рассмотрит дело о мошенничестве с муниципальной землей
iz.ru - get the latest breaking news, showbiz & celebrity photos, sport news & rumours, viral videos and top stories from iz.ru Daily Mail and Mail on Sunday newspapers.
El robot cuadrúpedo Spot se prepara para explorar las cuevas y cráteres de Marte
elcomercio.pe - get the latest breaking news, showbiz & celebrity photos, sport news & rumours, viral videos and top stories from elcomercio.pe Daily Mail and Mail on Sunday newspapers.
In early March, a gleaming white submarine called
Alvin surfaced off the Atlantic coast of North Carolina after spending the afternoon thousands of feet below the surface. The submarine’s pilot and two marine scientists had just returned from collecting samples around a methane seep, an oasis for carbon-munching microbes and the larger species of bottom dwellers that feed on them. It was the final dive of a month-long expedition that had taken the crew from the Gulf of Mexico up the East Coast, with stops along the way to explore a massive deep sea coral reef that had recently been discovered off the coast of South Carolina.