Orientation of the eruption fissures and composition of the lavas of the Miyakejima volcano is indicative of the competitive processes of the regional tectonic stress and the local stress generated by the activity of a magma plumbing system beneath the volcano. We examined the distributions and magmatic compositions of 23 fissures that formed within the last 2800 years, based on a field survey ...

Thin oceanic crust is formed by decompression melting of the upper mantle at mid-ocean ridges, but the origin of the thick and buoyant continental crust is enigmatic. Juvenile continental crust may form from magmas erupted above intraoceanic subduction zones, where oceanic lithosphere subducts beneath other oceanic lithosphere. However, it is unclear why the subduction of dominantly basaltic oc...

The straightforward but unexpected relationship presented here relates crustal thickness to magma type in the Izu-Ogasawara (Bonin) and Aleutian oceanic arcs. Volcanoes along the southern segment of the Izu-Ogasawara arc and the western Aleutian arc (west of Adak) are underlain by thin crust (10-20 km). In contrast those along the northern segment of the Izu-Ogasawara arc and eastern Aleutian a...

Quartz-rich xenoliths hosted in the basaltic–andesitic and andesitic lavas of Monte dei Porri, in the island of Salina, contain fluid and melt inclusions whose study makes it possible to trace back the magma ascent path of this volcano; moreover, they are a source of information about the anatectic processes that occurred under this island. The texture, mineralogy and whole-rock chemistry of th...

Abstract The volcanic Barva and Colima multiaquifer system is crucial for the drinking water supply of about 1.7 million people, 30% population in Costa Rica. complexity this simultaneous occurrence anthropogenic natural processes complicate understanding hydrochemical hydrogeological dynamics, both essential groundwater protection. This research aimed to develop a model discrimination groundwa...

Abstract An extensive deposit of agate occurs in Pedro González Island the Gulf Panama. Previous archaeological research showed that was exploited between 6200 and 5600 cal BP to make stone tools found at oldest known Preceramic human settlement Pearl archipelago. We constrain here origin geological context through a geochemical study island. show it includes primary volcanic breccias, lavas, t...

We report new petrographic and geochemical observations on magmatic sulfides occurring in different enclave types, including hornblende and/or clinopyroxene-rich cumulates, the host lavas, Nisyros (South Aegean volcanic arc). discuss our findings context of pre-existing petrological thermobarometry studies. Our results indicate that become less abundant Cu-richer (Cu median values) with magma d...