Andesites are refined and “cold” magmas compared to their basaltic parents, yet large volumes of andesites generated at continental arcs. We show that andesitic plutons favored when arc crust attains a thickness ~60 km while mafic small is thin. Using simple thermal models, we large, long-lived relatively cold partially molten zones, sustained by recharge hydrous magmas, depth thick due the red...

Concentrations of OH, and major and trace elements were determined in a suite of mantle-derived megacrysts that represent the crystallization products of a kimberlite-like magma at 5 GPa and 1400---1100 C. OH concentrations, determined by singlecrystal Fourier transform infrared spectroscopy, display the following ranges (ppmw H2O): olivine 54---262, orthopyroxene 215---263, garnet 15---74, cli...

Introduction: Evidence of cryomagmatism has been detected in some icy satellites such as Europa and Enceladus. Examples of cryomagmatic structures on Europa are domes of various sizes, flat materials covering older features and low albedo deposits around fractures. In Enceladus, the features are less obvious because the composition of the magmatic materials and the surrounding surface seems to ...

A megacrystal granodiorite, occurring in a pluton in the Monterey peninsula of California, is gradational south to quartz monzonite and then to tonalite and trondhjemite and southeast to granodiorite and then to tonalite. A primary magmatic origin for the pluton is indicated by normally zoned plagioclase crystals and by dikes that extend into biotite-hornblende quartz diorite southeast of Point...

A hot and acid crater lake is located in the Nakadake crater, Aso volcano, Japan. The volume of water in the lake decreases with increasing activity, drying out prior to the magmatic eruptions. Salt-rich materials of various shapes were observed, falling from the volcanic plume during the active periods. In May 2011, salt flakes fell from the gas plume emitted from an intense fumarole when the ...

Crustal extension at mature continental rifts and oceanic ridges occurs by a combination of normal faulting and magma injection, which interact to create rift morphology. Quantifying the relative roles of faulting and melt intrusion in accommodating extension at magmatic rifts remains difficult and requires studies at sufficient spatial and temporal scales to resolve the interaction between the...

Article history: Received 5 October 2016 Received in revised form 2 June 2017 Accepted 6 June 2017 Available online 8 June 2017 Following a cessation in eruptive activity it is important to understand how a volcano will behave in the future and when it may next erupt. Such an assessment can be based on the volcano's long-term pattern of behaviour and insights into its current state via monitori...

U-Pb dates on magmatic and detrital zircon from samples in the hinterland of the Taconic orogen place new constraints on the timing and plate tectonic geometry of terrane accretion and magmatic arc activity. The Moretown terrane, a Gondwanan-derived exotic block, extends from the Rowe Schist-Moretown Formation contact in the west to the Bronson Hill arc in the east. Arc-related plutonic and vol...