Posts Tagged ‘Elements’

Scientists in Need of Arts Training

How can universities train our scientists, technologists and engineers to engage with society rather than perform as cogs in the engine of economic development? Author Richard Lachman asks for educational system to require STEM students to take art and humanities courses, not as an attempt to “broaden minds” but as a necessary discussion of morals, ethics and responsibility.

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Primordial black holes may have helped to forge heavy elements

San Diego CA (SPX) Aug 07, 2017

Astronomers like to say we are the byproducts of stars, stellar furnaces that long ago fused hydrogen and helium into the elements needed for life through the process of stellar nucleosynthesis.

As the late Carl …

Atmosphere of distant ‘warm Neptune’ fascinates astronomers

A mixture of images from NASA’s Hubble and Spitzer telescopes has resulted in fascinating observations of the exoplanet HAT-P-26b, which is classified as a ‘warm Neptune’. Water vapor and exotic clouds have been spotted in the atmosphere of the distant alien planet, which is 430 light-years away from Earth. The planet displayed a preponderance of […]

The post Atmosphere of distant ‘warm Neptune’ fascinates astronomers appeared first on Redorbit.

Jumping genes act like parasites in the cell?

From ScienceDaily: Nature is full of parasites — organisms that flourish and proliferate at the expense of another species. Surprisingly, these same competing roles of parasite and host can be found in the microscopic molecular world of the cell. A new study by two Illinois researchers has demonstrated that dynamic elements within the human genome […]

Implications for metal and volatile cycles from the pH of subduction zone fluids

The chemistry of aqueous fluids controls the transport and exchange—the cycles—of metals and volatile elements on Earth. Subduction zones, where oceanic plates sink into the Earth’s interior, are the most important geodynamic setting for this fluid-mediated chemical exchange. Characterizing the ionic speciation and pH of fluids equilibrated with rocks at subduction zone conditions has long been a major challenge in Earth science. Here we report thermodynamic predictions of fluid–rock equilibria that tie together models of the thermal structure, mineralogy and fluid speciation of subduction zones. We find that the pH of fluids in subducted crustal lithologies is confined to a mildly alkaline range, modulated by rock volatile and chlorine contents. Cold subduction typical of the Phanerozoic eon favours the preservation of oxidized carbon in subducting slabs. In contrast, the pH of mantle wedge fluids is very sensitive to minor variations in rock composition. These variations may be caused by intramantle differentiation, or by infiltration of fluids enriched in alkali components extracted from the subducted crust. The sensitivity of pH to soluble elements in low abundance in the host rocks, such as carbon, alkali metals and halogens, illustrates a feedback between the chemistry of the Earth’s atmosphere–ocean system and the speciation of subduction zone fluids via the composition of the seawater-altered oceanic lithosphere. Our findings provide a perspective on the controlling reactions that have coupled metal and volatile cycles in subduction zones for more than 3 billion years7.

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