Experimental production of K-rich metasomes through sediment recycling at the slab-mantle interface in the fore-arc.

Sediment contribution to the mantle is the key step for the generation of orogenic magmatism to produce its isotopic and geochemical inventory. Even though they are exceptional for the post-collisional settings, there are worldwide examples of arc-related ultrapotassic mafic magmas which require complex multi-stage processes along with sediment melting e.g.

Rapid quench piston cylinder apparatus: An improved design for the recovery of volatile-rich geological glasses from experiments at 0.5-2.5 GPa.

The accurate and precise determination of the compositions of silicate glasses formed from melts containing volatile components H2O and CO2 recovered from high-pressure, high-temperature experiments is essential to our understanding of geodynamic processes taking place within the planet. Silicate melts are often difficult to analyze chemically because the formation of quench crystals and overgrowths on silicate phases is rapid and widespread upon quenching of experiments, preventing the formation of glasses in low-SiO2 and volatile-rich compositions. Here, we present experiments conducted in a novel rapid quench piston cylinder apparatus on a series of partially molten low-silica alkaline rock compositions (lamproite, basanite, and calk-alkaline basalt) with a range of water contents between 3.

Origin of potassic postcollisional volcanic rocks in young, shallow, blueschist-rich lithosphere.

Potassium-rich volcanism occurring throughout the Alpine-Himalayan belt from Spain to Tibet is characterized by unusually high Th/La ratios, for which several hypotheses have brought no convincing solution. Here, we combine geochemical datasets from potassic postcollisional volcanic rocks and lawsonite blueschists to explain the high Th/La. Source regions of the volcanic melts consist of imbricated packages of blueschist facies mélanges and depleted peridotites, constituting a new mantle lithosphere formed only 20 to 50 million years earlier during the accretionary convergence of small continental blocks and oceans.

Melting of sediments in the deep mantle produces saline fluid inclusions in diamonds.

Diamonds growing in the Earth's mantle often trap inclusions of fluids that are highly saline in composition. These fluids are thought to emerge from deep in subduction zones and may also be involved in the generation of some of the kimberlite magmas. However, the source of these fluids and the mechanism of their transport into the mantle lithosphere are unresolved.

In vitro study on dental erosion caused by different vinegar varieties using an electron microprobe.

Background: Among health-conscious individuals, including vegetarians, salads dressed with vinegar are frequently consumed. Dental erosion can also be caused by an acidic diet, and occurs with increasing tendency. The aim of this study was to analyze the erosive potential of vinegar varieties on human enamel samples.

Evolution of the Archaean crust by delamination and shallow subduction.

The Archaean oceanic crust was probably thicker than present-day oceanic crust owing to higher heat flow and thus higher degrees of melting at mid-ocean ridges. These conditions would also have led to a different bulk composition of oceanic crust in the early Archaean, that would probably have consisted of magnesium-rich picrite (with variably differentiated portions made up of basalt, gabbro, ultramafic cumulates and picrite). It is unclear whether these differences would have influenced crustal subduction and recycling processes, as experiments that have investigated the metamorphic reactions that take place during subduction have to date considered only modern mid-ocean-ridge basalts.