Mantle Rock Drilled Up in Cores

[BillTre]

As reported in Science magazine, so maybe pay-walled.

This month, researchers onboard the JOIDES Resolution, the flagship of the International Ocean Discovery Program (IODP), say they have finally succeeded. Drilling below the seabed in the mid–Atlantic Ocean, they have collected a core of rock more than 1 kilometer long, consisting largely of peridotite, a kind of upper mantle rock.

Researchers on land are eagerly following the ship’s daily scientific logs as it continues to drill, says Jessica Warren, a mantle geochemist at the University of Delaware.

There’s still some room for debate about whether the rocks are a true sample of the mantle, says Donna Blackman, a geophysicist at the University of California, Santa Cruz. The seismic speedup at the Moho is thought to reflect the lack of water or calcium and aluminum minerals in mantle rocks. Because the samples still show some influence of seawater, Blackman says she might classify them as deep crust. “But the petrology is interesting and special regardless,” she says. And as the team continues drilling into deeper rocks, Lissenberg says, “They’re getting fresher.”Indeed, it appears the team is already sampling mantle rock that has never melted into magma, which then cools and crystallizes into different kinds of crustal rocks, says Vincent Salters, a geochemist at Florida State University. By capturing the rock at this point, he says, researchers should be able to learn how magma melts, flows, and separates—clues to the workings of volcanoes worldwide.

The rock cores contained veins of asbestos, necessitating extra safety protocols.Lesley Anderson/U.S. Antarctic Program & IODP

 

[pinball1970]

As reported in Science magazine, so maybe pay-walled.

It looks like marble! Wow!