Sentences with phrase «subducting slabs»

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.

Instead, subducting slabs would have sunk straight to the bottom of the mantle, establishing their final resting place just above the Earth's core.

For the most part, today's subducting slabs can only sink so far, to about 670 kilometers below the surface, before the mantle's makeup turns from a honey - like consistency, to that of paste — too dense for most slabs to penetrate further.

They looked to compare the density of subducting slabs at that time with the density of the surrounding mantle, the difference of which would determine how far slabs would have sunk.

«Tearing and breakoff of the subducted slabs as the result of a collision of the Panama arc - indenter with northwestern South America,» appears in the June 2013 issue of BSSA.

Klein used the composition of each rock sample to calculate the density of a typical subducting slab, for both the modern day and 3 billion years ago.

He then estimated the average temperature of a modern versus an ancient subducting slab, relative to the temperature of the surrounding mantle.

«We find that around 3 billion years ago, subducted slabs would have remained more dense than the surrounding mantle, even in the transition zone, and there's no reason from a buoyancy standpoint why slabs should get stuck there.

He explained that earthquakes aren't evenly spread within the subducting slab, meaning there are potentially areas where an earthquake is more or less likely to take place.

The subducted Pacific plate beneath the Sea of Okhotsk (located between the Kamchatka Peninsula and the Russian mainland) is a lot colder than the subducted slab where the 1994 Bolivia earthquake occurred.

The team found that the subducting slab — a portion of the oceanic plate that slides beneath a continental plate — is the dominant driving force behind the deformation of the mantle.

As a result, mantle plumes entrain a variable combination of relatively young oceanic crust directly from the subducting slab, older oceanic crust that has been stirred with ancient more primitive material and background, depleted mantle.

Some geologists think that subducted slabs of lithosphere have settled there.

Not exact matches

Now seismologists have identified the «Caldas tear,» which is a break in a slab that separates two subducting plates and accounts for curious features, including a «nest» of seismic activity beneath east - central Colombia and high grade mineral deposits on the surface.

Here, a slab of the Pacific Ocean floor called the Juan de Fuca plate slides eastward and downward, «subducting» underneath the continental plate of North America.

The combination of a hotter mantle and denser rocks likely caused subducting plates to sink all the way to the bottom of the mantle, 2,800 kilometers below the surface, forming a «graveyard» of slabs atop the Earth's core.

As the model helps explain, a volcano can form inland if the slab subducts at a shallower angle, and a hole in the shallow slab allows for a special type of magma to form by melting of the crust.

As the subducting plate sinks deeper into the earth, it encounters higher and higher temperatures and pressures, which release the significant amount of water trapped in waterrich minerals that exist within the slab.

The model showed that if there were varying amounts of salt in the surface ice shell, it could provide the necessary density differences for a slab to subduct.

The research, published in the journal Nature Geoscience, found that the Earth's largest flat slab, located beneath Peru, where the oceanic Nazca Plate is being subducted under the continental South American Plate, may be relatively weak and deforms easily.

This could change the friction between the subducting and the overlying slabs.