Mantle control on silicic volcanism

Mantle updrafts and mechanisms of oceanic volcanism.

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...

Silicic volcanism on Mars evidenced by tridymite in high-SiO2 sedimentary rock at Gale crater.

Tridymite, a low-pressure, high-temperature (>870 °C) SiO2 polymorph, was detected in a drill sample of laminated mudstone (Buckskin) at Marias Pass in Gale crater, Mars, by the Chemistry and Mineralogy X-ray diffraction instrument onboard the Mars Science Laboratory rover Curiosity The tridymitic mudstone has ∼40 wt.% crystalline and ∼60 wt.% X-ray amorphous material and a bulk composition wit...

Silicic Volcanism on Io? Evidence from Tohil Mons and Other Possible Volcanic Cones

INTRODUCTION Recent volcanic activity of Io generally does not produce conical mountains. Instead, their lava run out in thin, long flows. Volcanic centers are typically large, deep calderas cut into the interpatera plains. Bright lava flows on Io can mostly be associated with sulfur lavas, with no visible escarpments that would indicate higher viscosity material. From temperature measurements ...

Possible distinguishing characteristics of very deepwater explosive and effusive silicic volcanism

Recent seafloor exploration has shown that volcanic-hosted massive sulfides (VHMS) occur in modern silicic calderas formed by highly explosive eruptions at substantial water depths. Sampling of these has so far been restricted to surficial deposits. Ancient analogs provide a time-integrated view of the structure and fill of deepwater calderas, but constraints on paleo-water depths have previous...

Understanding silicic volcanism: Constraints from elasticity and failure of vesicular magma