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TOPIC: Earth's mantle
Blobrana


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Taking Earth's Inner Temperature

A new study led by Woods Hole Oceanographic Institution (WHOI) suggests the mantle - the mostly solid, rocky part of Earth's interior that lies between its super-heated core and its outer crustal layer - may be hotter than previously believed. The new finding, published March 3 in the journal Science, could change how scientists think about many issues in Earth science including how ocean basins form.
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Blobrana


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New model of Earth's interior reveals clues to hotspot volcanoes

Scientists at the University of California, Berkeley, have detected previously unknown channels of slow-moving seismic waves in Earth's upper mantle, a discovery that helps explain "hotspot volcanoes" that give birth to island chains such as Hawaii and Tahiti.
Unlike volcanoes that emerge from collision zones between tectonic plates, hotspot volcanoes form in the middle of the plates. The prevalent theory for how a mid-plate volcano forms is that a single upwelling of hot, buoyant rock rises vertically as a plume from deep within Earth's mantle - the layer found between the planet's crust and core - and supplies the heat to feed volcanic eruptions.
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Blobrana


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Deep Earth Heat Surprise

The key to understanding Earth's evolution is to look at how heat is conducted in the deep lower mantle - a region some 660 to 2,900 kilometres below the surface. Researchers at the Carnegie Institution, with colleagues at the University of Illinois, have for the first time been able to experimentally simulate the pressure conditions in this region to measure thermal conductivity using a new measurement technique developed by the collaborators and implemented by the Carnegie team on the mantle material magnesium oxide (MgO). They found that heat transfer is lower than other predictions, with total heat flow across the Earth of about 10.4 terawatts, which is about 60 % of the power used today by civilization. They also found that conductivity has less dependence on pressure conditions than predicted. The research is published in the August 9, online Scientific Reports.
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Congestion in the Earth's Mantle

Mineralogists explain in the science magazine 'Nature Geoscience' why plate tectonics stagnates in some places
The Earth is the only planet in our solar system, conducting such a 'facelift' on a regular basis. But the continuous up and down on the Earth's crust doesn't run smoothly everywhere.
"Seismic measurements show that in some mantle regions, where one slab is subducted underneath another one, the movement stagnates, as soon as the rocks have reached a certain depth," says Prof. Langenhorst.
The causes of the 'congestion' of the subducted plate are still unknown. In the current issue of the science magazine 'Nature Geoscience' Prof. Langenhorst and earth scientists of Bayreuth University now explain the phenomenon for the first time (DOI: 10.1038/NGEO1772).
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 Delving inside Earth from space

ESA astronaut André Kuipers is running experiments on the International Space Station that are shedding light on conditions deep inside Earth. Orbiting some 400 km above us, Geoflow is offering insights into the inner workings of our planet.
Descending 3000 km under our feet, Earth's mantle is a semi-solid fluid under our thin outer crust. The highly viscous layers vary with temperature, pressure and depth.
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Using 2.8-billion-year-old rock, researchers overturn widespread belief about content of the Earth's mantle 

While searching for one scientific breakthrough, university geology professor Richard Walker and his research team stumbled across another - parts of Earth's mantle remained unchanged through the chaotic period after its formation.
From about 2.8 to 4.5 billion years ago, the Earth was experiencing growing pains. Collections of cosmic dust were bombarding the Earth, and until now, the scientific community widely believed Earth melted, erasing remnants of one of early Earth's interior layers - the mantle.
Using a 2.8 billion-year-old rock from Russia, Walker and his team of two researchers proved that this widespread belief was false.
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Building Blocks of Early Earth Survived Collision that Created Moon

Unexpected new findings by a University of Maryland team of geochemists show that some portions of the Earth's mantle (the rocky layer between Earth's metallic core and crust) formed when the planet was much smaller than it is now, and that some of this early-formed mantle survived Earth's turbulent formation, including a collision with another planet-sized body that many scientists believe led to the creation of the Moon.
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Journey to the Earth's Core - History Channel

Humans have mapped every corner of the globe -- from jungles and deserts to the depths of space. Yet we've gone only seven miles below the Earth's surface -- just one five hundredth of the way to the Core



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Title: Experimental and Theoretical Evidence for Pressure-Induced Metallisation in FeO with Rocksalt-Type Structure
Authors: Kenji Ohta, R. E. Cohen, Kei Hirose, Kristjan Haule, Katsuya Shimizu, and Yasuo Ohishi

Electrical conductivity of FeO was measured up to 141 GPa and 2480 K in a laser-heated diamond-anvil cell. The results show that rock-salt (B1) type structured FeO metallises at around 70 GPa and 1900 K without any structural phase transition.

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New discoveries resolve debate over oxygen in Earth's mantle

Recent discoveries by a University of Rhode Island scientist are bringing resolution to the debate among geologists about the availability of oxygen in the Earth's mantle.
Analysis of erupted rock from Agrigan volcano in the western Pacific near Guam has found it to be highly oxidized as a result of its exposure to oxygen when it formed in the Earth's mantle.
When, over millions of years, seafloor rocks are transported back into the Earth's mantle at subduction zones - sites on the seafloor where tectonic plates have collided, forcing one plate beneath the other - they deliver more oxygen into the mantle.
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