Sentences with phrase «upper mantle rocks»

That's because the rising magma that produced the lavas probably mixed with upper mantle rocks, which have been contaminated with isotopically heavy surface water that got dragged down by subducting slabs of tectonic plates.

Senior author Barbara Romanowicz, a UC Berkeley professor of earth and planetary science, noted that the connections between the lower - mantle plumes and the volcanic hotspots are not direct because the tops of the plumes spread out like the delta of a river as they merge with the less viscous upper mantle rock.

Not exact matches

Professor Damon Teagle, from Ocean and Earth Science at the University of Southampton and a veteran of numerous scientific ocean drilling expeditions, said: «It is very exciting for IODP to be using a British ship and new technologies to investigate the strange reactions that occur when seawater meets rocks of the upper mantle.

Looking at the entire upper mantle, the scientists found that the most powerful process causing rocks to flow happens in the upper part of the lithosphere as new sea floor is created at a mid-ocean ridge.

The researchers say this indicates an upper crust made of a mixture of rock and ice — in which small craters could be carved — supported by a more viscous mantle of ice lower down, which would allow the biggest impact basins to relax away with time, like silly putty returning to its original shape.

Earth's upper mantle, which makes up much of the lithosphere, is a relatively simple mix, consisting primarily of two rock types, olivine and pyroxene.

Everything on the surface of the Earth rests on massive tectonic plates that resemble a jelly sandwich, with two rigid pieces — the upper crust and the upper mantle — enclosing a gooey middle layer of very hot rocks, which is the lower crust.

Romanowicz, who uses seismic waves to study Earth's interior, had previously worked with French, then a graduate student, on a tomographic model of the upper 800 kilometers of the mantle, which showed periodic hot and cold regions of rock underlying hotspot volcanoes.

Although the heat of the upper mantle might help the olivine or pyroxene crystals within the rocks grow larger again, or «heal,» the two rock types are competing for space: Each is actually inhibited in its growth by the other's presence.

That's the conclusion from experiments on rocks typical of those in the mantle transition zone, a layer 410 to 660 kilometres beneath us that separates the upper from the lower mantle.

«Melting of rock at this depth is remarkable because most melting in the mantle occurs much shallower, in the upper 50 miles,» said Schmandt, a co-author of the paper.

During the last glacial maximum, Wiens explained, the weight of the ice bent the Earth's crust, forcing the plastic rock in the upper layer of the Earth's mantle to flow away from the loaded region.

A small fraction of the magnetic field comes from magnetised rocks in the upper lithosphere, which includes Earth's rigid crust and upper mantle.

massive slab of solid rock made up of Earth's lithosphere (crust and upper mantle).

By examining the cooling rate of rocks that formed more than 10 miles beneath the Earth's surface, scientists led by The University of Texas at Austin Jackson School of Geosciences have found that water probably penetrates deep into the crust and upper mantle at mid-ocean spreading zones, the places where new crust is made.

Lithosphere - The upper layer of the solid Earth, both continental and oceanic, which comprises all crustal rocks and the cold, mainly elastic part of the uppermost mantle.