Tephra layers in marine sediment cores from scientific ocean drilling largely record high-magnitude silicic explosive eruptions in the Japan arc for up to the last 20 million years. Analysis of the thickness variation with distance of 180 tephra layers from a global data set suggests that the majority of the visible tephra layers used in this study are the products of caldera-forming eruptions ...

Carbon dioxide released by arc volcanoes is widely considered to originate from the mantle and from subducted sediments. Fluids released from upper arc carbonates, however, have recently been proposed to help modulate arc CO2 fluxes. Here we use boron as a tracer, which substitutes for carbon in limestone, to further investigate crustal carbonate degassing in volcanic arcs. We performed laborat...

We investigate the genetic variation between populations of the American sweetgum (Liquidambar styraciflua), a tree species with a disjunct distribution between northeastern Texas and Mexico, by analyzing sequences of two chloroplast DNA plastid regions in Mesoamerica. Our results revealed phylogeographical structure, with private haplotypes distributed in unique environmental space at either s...

Semi-massive to massive sulfides with abundant late native sulfur were drilled in a shallowwater hydrothermal system in an island arc volcanic setting at the Palinuro volcanic complex in the Tyrrhenian Sea, Italy. Overall, 12.7 m of sulfide mineralisation were drilled in a sediment-filled depression at a water depth of 630 650 m using the lander-type Rockdrill I drill rig of the British Geologi...

Climate trends on timescales of 10s to 100s of millions of years are controlled by changes in solar luminosity, continent distribution, and atmosphere composition. Plate tectonics affect geography, but also atmosphere composition through volcanic degassing of CO2 at subduction zones and midocean ridges. So far, such degassing estimates were based on reconstructions of ocean floor production for...

We investigated calcite globules and veins in two spinel-garnet peridotite xenoliths from the subSierra Nevada mantle. The studied xenoliths were entrained in a Miocene (11 Ma) volcanic plug. These carbonates are associated spatially with silicate glass inclusions, suggesting that they are primary inclusions—inclusions that formed at high temperature in the mantle and not at or close to the Ear...

Oblique subduction at a high rate of convergence along much of the Middle America Trench results in northwest-directed trench-parallel block motion. Accommodation of this motion along northwest-striking dextral strike-slip faults has been postulated; however, in Nicaragua such faults are not well developed. We suggest instead that this motion is accommodated by bookshelf faulting that includes ...

The Johanson Lake project is a two-year bedrock mapping program initiated by the Geological Survey and Development Branch in 2003 as part of the Toodoggone Targeted Geoscience Initiative (TGI). The project is focused on a belt of Mesozoic arc volcanic and plutonic rocks of the Quesnel Terrane in the eastern part of the McConnell Creek (94D) map sheet. This area contains a number of MINFILE occu...