Primitive, low-silica and high-alkali magmas that erupt late in the evolution of most ocean island volcanoes are highly enriched in incompatible trace elements, yet their isotopic compositions require a time-integrated mantle source history of incompatible-element depletion. Reconciling these observations has traditionally required either extremely low degrees of partial melting of depleted man...

[1] The electrical conductivity of mantle minerals is highly sensitive to parameters that characterize the structure and state of the lithosphere and sublithospheric mantle, and mapping its lateral and vertical variations gives insights into formation and deformation processes. We review state‐of‐the‐art conductivity models based on laboratory studies for the most relevant upper mantle minerals...

Here we report the first set of thallium (Tl) isotope data in alkaline rocks from North China Craton to constrain nature recycled materials metasomatized subcontinental lithospheric mantle. Samples Hekanzi and Saima complexes display Tl compositions (ε205Tl) identical present-day upper mantle continental crust, suggesting that neither low-temperature altered oceanic crust nor pelagic sediments ...

Convection in an isolated planet is characterized by narrow downwellings and broad updrafts--consequences of Archimedes' principle, the cooling required by the second law of thermodynamics, and the effect of compression on material properties. A mature cooling planet with a conductive low-viscosity core develops a thick insulating surface boundary layer with a thermal maximum, a subadiabatic in...

Pipe-like ultramafic bodies, hosting Ni–Cu–PGE sulphide deposits, INTRODUCTION intrude the Main Gabbro and the roof metasediments of the Ivrea The Ivrea Zone, in NW Italy, is believed to represent an Zone, NW Italy. These bodies were emplaced at 287 ± 3 Ma exposed section of the lower continental crust (Mehnert, and represent the last mantle-derived melts associated with an 1975; Garuti et al.,...

Os-, Nd-, and Pb-isotope measurements were performed on a suite of eleven Kamchatka peridotite mantle xenoliths in volcanics from the southern (Avachinsky) and central (Sheveluch and Kharchinsky) segments of the Kamchatka peninsula. Peridotites with higher Os content (1.3–5.2 ppb) show a narrow Os / Os range between 0.1182 and 0.1272 while the xenoliths with lower Os content (b1 ppb) show a wid...

The volcanic hazard potential of Mount Etna volcano is currently nourished by longlasting , powerful eruptions of basaltic magmas coupled with increased seismicity and ground deformation, and the world’s largest discharge of volcanic gases. The current evolutionary cycle of Mount Etna activity is consistent with subduction-related chemical modifi cations of the mantle source. Arrival of a new m...