Sentences with phrase «oceanic crust»
Oceanic crust refers to the solid outer layer of the Earth's surface beneath the ocean. It is made up of rocks and minerals that formed through volcanic activity and is thinner and denser than continental crust. It plays an important role in forming the ocean floor and is constantly being created and destroyed through movements of tectonic plates. Full definition
If that's the reason, it could be because the crust is about 25 kilometers thick, resembling continental crust, compared with the 5 to 10 kilometers of oceanic crust elsewhere.
sciencemag.org
The vents were shown to be associated with the formation of new oceanic crust.
There is some evidence that the eruptions also brought up remnants of ancient oceanic crust, which had been forced deep into the mantle long ago.
It means the continents effectively «float» on the underlying oceanic crust, which in turn sits on the fluid material of the mantle.
Song and team believe that it may be subducted oceanic crust at unusually high levels of water saturation.
The scarps are cliffs that expose and provide access to the subseafloor, without the need for drilling, making it easier to tease out what is living at depth in oceanic crust.
To address that, Hubert Staudigel of the Scripps Institution of Oceanography at the University of California at San Diego and his colleagues studied cores extracted from oceanic crust of various ages and settings.
It's the first time this tectonic process has been discovered beneath land; all other known subduction zones occur underwater where oceanic crusts meet.
The relatively low - density continental crust of the North Island, which sits on the Australian plate, is forcing the dense oceanic crust on the Pacific plate beneath it in a process called subduction.
As a member of the American Miscellaneous Society, Munk helped initiate the Moho project to drill into oceanic crust.
Roughly 60 % of the Earth's outer surface is composed of oceanic crust formed by volcanic processes at mid-ocean ridges.
Five kilometers down is the beginning of a large magma chamber lying partially within old oceanic crust that had been buried by more than 8 km of eruptive rock layers.
The result explains several puzzles that have bothered scientists about the mantle beneath oceanic crust, Dasgupta said in a statement.
Carbonates are important constituents of marine sediments and are heavily involved in the planet's deep carbon cycle, primarily due to oceanic crust sinking into the mantle, a process called subduction.
But an open question is whether the flood also tore through the eastern Mediterranean, over a seafloor cliff separating the shallower continental crust in the west from the deeper oceanic crust in the east.
But volcanoes were still spewing into the atmosphere large amounts of carbon from recycled oceanic crust.
But geophysicists had thought that great subduction - zone earthquakes happened only where younger oceanic crust scrapes its way into the mantle.
This uranium isotope «fingerprint» of the altered oceanic crust provides a way to trace uranium that has moved from the surface and back into Earth's interior through subduction.
«This study is the first geophysical observation that large magma chambers exist in the deep oceanic crust below.»
Magma from the mantle forms oceanic crust when it rises from the mantle to the surface at spreading centers and cools into the rock that forms the very bottom of the seafloor.
This is consistent with the plate tectonic model: between Greenland and Scandinavia thick and heavy material rises up from the Earth's mantle along the mid-ocean ridge, cools down and creates fresh oceanic crust.
However, the mantle remained so hot that it softened the subducting oceanic crust too much for it to pull large areas of continental crust down behind it, as it does today.
Vast quantities of ocean water circulate through the seafloor, flowing through the volcanic rock of the upper oceanic crust.
The northwest Pacific crust that is subducting in this area is some of the oldest, coldest oceanic crust subducting on Earth.
In particular, the researchers found that a higher ratio of uranium - 238 to uranium - 235 is incorporated into the modern oceanic crust, when compared to the uranium isotope signature found in meteorites.
«Some material might be associated with former basaltic oceanic crust that got subducted deeply.
The surface rock of Mauritius is made from volcanic oceanic crust, or basalt.
Although a few of Earth's largest islands, such as Greenland, are composed of the same continental crust as the mainland, most islands are made of a denser, chemically distinct oceanic crust, created midocean by magma welling up beneath separating tectonic plates.
Those fragments, the researchers say, lie buried beneath more recent oceanic crust erupted by underwater volcanoes.
For instance, oceanic crust loaded with carbon - rich sediment could delve, or subduct, to mix with the upper mantle layer of hot rock that reaches about 410 miles (660 kilometers) down, or even to the lower mantle below that.
«There's a debate in the scientific community how oceanic crust forms,» Dygert said.
Hiking first through a barren landscape, women discover where the peridotite ends and ancient oceanic crust begins.
The trench is created by the subduction of some of the world's oldest oceanic crust, which plunges underneath the Mariana Isalnds so steeply at places that it is going almost straight down.
Geophysical data, they note, demonstrate that India's basement rock flexes and slides beneath the Himalaya much like the earthquake - ridden subducting oceanic crust.
Generally speaking, there are two types of crust on Earth: a lighter continental crust that is rich in silicon and constitutes the dry land above sea level, and a denser oceanic crust where water gathers in the form of large oceans.
It has long been suggested that Earth's mantle contains several different compositional reservoirs, including an ancient more - primitive reservoir at the lowermost mantle, recycled oceanic crust and depleted background mantle.
«These superdeep diamonds contained much less carbon - 13, which is most consistent with an origin in the organic component found in altered oceanic crust.»
This makes the continental crust lighter than the underlying oceanic crust, which is primarily silica and magnesium, Sima.
Magma that's mostly from the deeper mantle, however, doesn't produce a lot of lithium, neither does magma melted from oceanic crust.
There it will seek out new species and habitats; it may also study subduction zones, where oceanic crust is recycled back into the earth's mantle.
Cycling of oceanic crust through mantle reservoirs can therefore explain observations of different recycled oceanic crustal ages and explain the chemical complexity of hotspot lavas.
@Aashish Loknath Panigrahi: Yes, there are some plates that only consist of oceanic crust (especially in the Pacific); but more relevant is that all the continental plates also have portions of oceanic crust.