[1] We measure all stable noble gases (He, Ne, Ar, Kr, Xe) in spring waters in the Oregon Cascades volcanic arc and in eastern Oregon, USA. We show that in order to estimate magmatic helium (He) contributions it is critical to simultaneously consider He isotopic ratios, He concentrations, and mixing of He components. Our component mixing analysis requires consideration of all measured noble gas...

Widespread ash dispersal poses a significant natural hazard to society, particularly in relation to disruption to aviation. Assessing the extent of the threat of far-travelled ash clouds on flight paths is substantially hindered by an incomplete volcanic history and an underestimation of the potential reach of distant eruptive centres. The risk of extensive ash clouds to aviation is thus poorly...

Shallow submarine volcanoes have been newly discovered near the Tokara Islands, which are situated at the volcanic front of the northern Ryukyu Arc in southern Japan. Here, we report for the first time the volatile geochemistry of shallow hydrothermal plumes, which were sampled using a CTD-RMS system after analyzing water column images collected by multi-beam echo sounder surveys. These surveys...

Abstract The Payenia region of Argentina (34.5–38°S) is a large Pliocene‐Quaternary volcanic province basaltic compositions in the Andean Cordillera foothills representing northernmost extent back‐arc volcanism Southern Volcanic Zone (SVZ). Although chemical diversity basalts has been characterized previously, processes and sources responsible for such variation remain controversial. Here, we r...

This paper presents the new geochemical isotopes Sr and Nd, and the mineralization data for the south Neyshabour volcanic rocks located in NE Iran. Based on the chemical classifications, the studied rocks are basaltic trachy andesite, trachy andesite, trachyte, and trachy dacite in composition. All the analyzed volcanic rocks display enrichment in light rare earth elements (LREE) relative to th...

Tectonic collision between South America and Panama began at 23–25 Ma. The collision is signifi cant because it ultimately led to development of the Panamanian Isthmus, which in turn had wide-ranging oceanic, climatic, biologic, and tectonic implications. Within the Panama Canal Zone, volcanic activity transitioned from hydrous mantle-wedge−derived arc magmatism to localized extensional arc mag...

Late Miocene (7–9 Ma) basaltic rocks from the Monbetsu-Kamishihoro graben in northeast Hokkaido have chemical affinities to certain back-arc basin basalts (referred to herein as Hokkaido BABB). Pb-, Ndand Sr-isotopic compositions of the Hokkaido BABB and arc-type volcanic rocks (11–13 Ma and 4–4.5 Ma) from the nearby region indicate mixing between the depleted mantle and an EM II-like enriched ...

a r t i c l e i n f o a b s t r a c t Keywords: full-wave ambient noise tomography the Cascadia subduction zone low-velocity anomaly decompressional melting Melt generation and volcanism at subduction zones may result from several possible processes: hydration of the mantle wedge by fluid released from the slab, subduction-induced mantle upwelling beneath the back-arc, and heating of downgoing ...