Barren ground depressions, natural H and orogenic gold deposits: Spatial link and geochemical model.

A review of the localities in continental rocks where H-rich gases have been reported, showed that they are mainly located near orogenic gold deposits. Two types of geomorphological features known as markers of gas venting in sedimentary basins were also systematically observed near orogenic gold deposits on satellite images. They consist in both barren ground depressions and high densities of small (<20 m in diameter) circular- and comet-shaped white spots in 32 and 7 localities, respectively.

Real-time monitoring of aqueous Hg reduction dynamics by magnetite/iron metal composite powders synthesized hydrothermally.

An iron-based powder material composed of zerovalent iron (8 wt.%) and magnetite (92 wt.%), has been synthesized hydrothermally at 200 °C from zero-valent iron.