The global flux of sulfur dioxide (SO2) emitted by passive volcanic degassing is a key parameter that constrains the fluxes of other volcanic gases (including carbon dioxide, CO2) and toxic trace metals (e.g., mercury). It is also a required input for atmospheric chemistry and climate models, since it impacts the tropospheric burden of sulfate aerosol, a major climate-forcing species. Despite i...

The Earth formed through accretion of planetesimals in 1–100 million years. Planetesimal impacts induce degassing, melting, and vaporization during accretion. The impact degassing, as well as the gravitational capture of the surrounding solar nebula gas, formed the proto-atmosphere on a growing Earth. The impact of heating and the blanketing effect of the proto-atmosphere resulted in the meltin...

Understanding the mechanisms that control the start-up of volcanic unrest is crucial to improve the forecasting of eruptions at active volcanoes. Among the most active volcanoes in the world are the so-called persistently degassing ones (e.g., Etna, Italy; Merapi, Indonesia), which emit massive amounts of gas during quiescence (several kilotonnes per day) and erupt every few months or years. Th...

Release of hypolimnetic water from man-made reservoirs can be a problem for downstream rivers. These effects can be significant mainly during the first years after the reservoir impoundment, especially in thermally stratified reservoirs favouring the release of anoxicmethane-richwater. In tropical areas, higher temperatures decrease the oxygen solubility and enhance chemical processes responsib...

Degassing of planetary interiors through surface volcanism plays an important role in the evolution of planetary bodies and atmospheres. On Earth, carbon dioxide and water are the primary volatile species in magmas. However, little is known about the speciation and degassing of carbon in magmas formed on other planets (i.e., Moon, Mars, Mercury), where the mantle oxidation state [oxygen fugacit...

The Moon contains chlorine that is isotopically unlike that of any other body yet studied in the Solar System, an observation that has been interpreted to support traditional models of the formation of a nominally hydrogen-free ("dry") Moon. We have analyzed abundances and isotopic compositions of Cl and H in lunar mare basalts, and find little evidence that anhydrous lava outgassing was import...

Many volcanoes exhibit temporal changes in their degassing process, from rapid gas puffing to lava fountaining and long-lasting quiescent passive degassing periods. This range of behaviors has been explained in terms of changes in gas flux and/or magma input rate. We report here a simple laboratory experiment which shows that the nonNewtonian rheology of magma can be responsible, alone, for suc...

11 The Orapa Diamond Mine (Republic of Botswana) exposes a bi-lobate kimberlite 12 pipe that erupted during the Late-Cretaceous epoch (∼93 Ma) through Archaean 13 basement and volcano-sedimentary rocks of the Karoo Supergroup. Geological map14 ping of the crater zone of the South Pipe has revealed a 15–25 m thick in-situ 15 kimberlite pyroclastic flow deposit. The pyroclastic deposit fills in t...