Authigenic magnesite, hydromagnesite and huntite associated with intensely altered and serpentinized ophiolitic rocks in Attica (mainland Greece) occur predominantly as veinlets and nodules within a totally weathered former serpentinite groundmass. Carbonate δ ¹⁸ O values are consistent with post-geothermal fluid temperatures between 25 and 70°C, but mostly between 25 and 30°C, from a dominantly meteoric-sourced groundwater, indicating near-surface, low-temperature conditions. Despite the proximity of a volcanic centre with strong CO ₂ flux, 75% of the carbon isotope data imply little or no incorporation of this CO ₂ into the authigenic Mg-(hydro)carbonates. Indeed, many δ ¹³ C values are more negative than soil-zone calcrete values, and in this setting Mg-(hydro)carbonate δ ¹³ C values below −6‰ VPDB probably indicate disequilibrium effects in alkaline groundwaters. Geothermal fluids and groundwaters were mainly routed through structural conduits. Some of the low-temperature hydromagnesite subsequently dehydrated to magnesite under near-surface conditions, and huntite is probably a diagenetic transformation of hydromagnesite, forming close to the volcanic centre where fluid Mg/Ca ratios were low. The isotopic signatures are distinct from previously published Balkan–East Mediterranean magnesite data arrays but are consistent with many other ultramafic-associated magnesium carbonates worldwide; their association with likely fluid compositions provides important context for Mg-(hydro)carbonate formation as geothermal conditions cool to near-surface temperatures.

The raw materials sector is undergoing significant structural changes. Skills required by emerging technologies and ever more challenging mineral deposits are changing quicker than todays’ workforce can update them. Education mainly focusses on “classical” raw materials related topics (geology, mining and mineral processing), whereas there are deficiencies in emerging and non-technical skills like communication and management. There is a strong need for both sides to understand the necessities and constraints of the respective other partner in this business. This paper generates a knowledge base for future analysis of raw materials education, identifying currently taught skills and the structure of higher education. A definition of skills, knowledge and teaching areas is presented, leading to a comprehensive “skills catalogue”. It builds the basis for an inventory of raw materials education worldwide.

The project proposal for the Desierto de los Leones tunnels in the Poetas Highway in Mexico aims to improve the excavation and support systems and evaluate the safety levels during construction. The design is based on geological and geotechnical information from the original project and can be approached using various methods, including numerical simulations. The article includes a summary of the lithological characteristics, a reinterpretation of geotechnical properties, a description of new construction procedures, and the results of calculations using the finite data differences method. The proposed project aims to improve the safety and stability of the tunnels through advanced construction technologies and adapted procedures, generated by a redesign and the scientific application of new techniques developed for this project.