Procedia Earth and Planetary Science最新文献

Sediments were taken from the Hetao basin to investigate effects of different lithologies and grain size distribution on As behaviors during oscillation of redox conditions. Total digestion and sequential extraction procedures showed that Fe and Mn oxide minerals played important roles for As accumulation. The co-variation of As, CIA (Chemical Index of Alteration), ICV (Index of Compositional Variability) and Al₂O₃/SiO₂ indicated that As were enriched in strongly chemical weathering sediments weathered from mature mudrocks. Two sediments samples with the same As contents (21.9 μg/g) but different lithologies (fine sand versus clay) were chosen for redox oscillation experiments. As released from clayey (C-1) suspension was lower than those in C-2 (grounded sand) and C-3 (sand). Under reducing conditions, the maximum As concentration in C-1 was 9.99 μg/L, however, it was 149 μg/L in C-2 and 120 μg/L in C-3. It inferred that the lithology and mineralogy play an important role in As fixation and mobilization. The grounded sands released more As in reducing conditions and sequestrated more As in oxic conditions relative to the pristine sands.

For almost 50 years Mike Edmunds pursued an accomplished and influential career in hydrogeochemistry. His research interests covered the gamut of groundwater quality issues ranging from the effects of acid rain on upland streams to the origin of deep basin brines, and spanned the globe. Almost from the start of his career he was involved with the IAGC's Water–Rock Interaction (WRI) Working Group, becoming a founding father of the triennial WRI symposia which commenced in 1974 and continue to this day. Mike was a geologist turned chemist but also, crucially, a ‘people person’. This combination of qualities created a tireless advocate for the subject of water–rock interaction in all its variety.

The origin of CO₂ in fluids from Icelandic high-temperature geothermal systems is predominantly magmatic. Emissions from producing areas have risen with increased production. Abnormal rises have been recorded due to magmatic activity and the onset of boiling due to increase in production. Natural flow is predominantly through soil but to a small extent via steam vents and steam heated pools. The extent of natural steam flow varies considerably between areas apparently due to the formation of carbonate deposits (mainly calcite) in relatively cool liquid dominated aquifers at shallow depths where these are present. The CO₂ concentration of fluids from aquifers at higher temperatures apparently decreases with temperature and is for instance very low (<1000 ppm) in fluid from IDDP-1, Krafla where the source temperature is 450 °C.

A hydrogeochemical study was completed in the south-eastern part of Poland on treatment waters. Waters occur in the region of city Solec-Zdrój. In brief, the hydrogeochemical characteristics of waters from boreholes (Szyb Solecki, Solec 2B, Solec II Karol, Dobrowoda, Wełnin) and springs (Senisławice, Gadawa, Szczerbaków, Piestrzec) are summarized. Types of therapeutic waters available in this area include: Ca-SO₄-HCO₃,H₂S, Na-Cl-SO₄,H₂S to Cl-Na,H₂S. These waters are found in the Cretaceous and Jurassic sedimentary rocks. Hydrogeochemical equilibrium of water - rock interactions in this environment in the area of Solec-Zdrój was assessed using the PHREEQC program.