Organic geochemical records of hydrothermal alteration at Idrija mercury deposit, Slovenia

A combined molecular and stable isotopes (C, N) investigation of the organic matter associated to the Idrija mercury deposit is being used to track the pathway of the mineralizing hydrothermal fluids and their interaction with the organic matter. The studied samples include regional barren rocks, and host rocks and ore from the mine. The Rock-Eval parameters indicate that the organic matter disseminated in regional and mine rocks is mature to post mature. The bitumens from mineralized samples are depleted in aliphatichydrocarbons and enriched in polycyclic aromatic hydrocarbons (PAH), aromatic sulfur compounds (S-PAH) and hydrogenated PAH. The isotopic compositions of kerogens, bitumens,and individual hydrocarbons point to thermal and oxidative degradation of indigenous and migrated bitumens during mineralization and later evolution of the Idrija deposit

Natural, cultural and industrial heritage as a basis for sustainable regional development within the Geopark Idrija project (Slovenia)

The Idrija Municipality, situated in the western part of Slovenia, extends over an area of 294 km2 with around 12,000 inhabitants. The area of Idrija is placed at the crossing of Dinaric and Alpine mountain ranges. This position is the reason for an exceptionally diverse surface with deep gorges, high Karst tablelands and mountain tops. Furthermore, the most important natural feature is Idrija mercury ore deposit which was exploited by the Idrija Mercury Mine Ltd. and was the leading force in the development of the region through centuries. Today, the mine is closed but it left an outstanding cultural and industrial heritage that needs to be conserved for future generations - local people to sustain their identity and for visitors. To present the richness of Idrija region the local authorities have put many efforts into establishment of the Geopark since 2007. In 2009 concrete steps were taken with the inventory, thematic trails, evaluation of geoheritage, educational programs, research thesis, etc. With this project the basis and guidelines for the establishment of the Geopark were set. In 2010, the activities have continued at the Municipality level by setting an organisation structure of the future Geopark.

The chemical species of mercury accumulated by Pseudomonas idrijaensis, a bacterium from a rock of the Idrija mercury mine, Slovenia

International audienceA mercury-resistant bacterial strain has been isolated from a rock of the Idrija mercury mine in Slovenia. The rock had 19 g carbon and 2952 mg mercury (Hg) per kg. Mass spectrometry and DNA sequencing showed that the bacterium belongs to the Pseudomonas genus. It is called Pseudomonas idrijaensis. This bacterial strain is sensitive to methylmercury (MeHg) like the reference P. aeruginosa strain PAO1, and is resistant to divalent mercury (Hg(II)) in contrast to PAO1. This difference could be attributed to the presence of the mer operon yet deprived of the merB gene encoding the organomercurial lyase, on the basis of whole genome sequencing. The P. idrijaensis mer operon displays the RTPCADE organization and is contained in the Tn5041 transposon. This transposon identified here occurs in other Gram-negative Hg-resistant strains isolated from mercury ores, aquatic systems and soils, including Pseudomonas strains from 15,000 to 40,000 years old Siberian permafrost. When P. idrijaensis was exposed to mercury chloride, two intracellular Hg species were identified by high energy-resolution XANES spectroscopy, a dithiolate Hg(SR)2 and a tetrathiolate Hg(SR)4 complex. P. idrijaensis had a much higher [Hg(SR)2]/[Hg(SR)4] molar ratio than bacteria lacking the mer operon when exposed to 4 µg Hg2+/L - resulting in an intracellular accumulation of 4.3 µg Hg/g dw. A higher amount of the Hg(SR)2 complex provides a chemical signature for the expression of the dicysteinate Mer proteins in response to mercury toxicity