China
Africa
Explore chapters and articles related to this topic
The base metal deposit of Jasenie-Soviansko (Nizke Tatry Mts., Slovakia): A fluid inclusion study
Published in Adam Piestrzyński, Mineral Deposits at the Beginning of the 21st Century, 2001
J. Luptáková, M. Chovan, M. Huraiová
Quartz coeval with galena stage mineralization contains two- or three-phase aqueous fluid inclusions at room temperature. Vapour bubble in the inclusions occupies less than 10 vol %. Solid phase is represented by halite crystal. In many cases, halite was not present at room temperature, however, it appeared after melting down of frozen inclusion. Eutectic temperatures vary within the range −56.0 and −49.6°C, which corresponds to the NaCl-CaCl2-H2O system (Borisenko 1977). The next phase transition between −30.0 and −22.3°C was melting of ice. Hydrohalite was metastable and melted down at the temperatures above zero. Frequently, halite appeared exactly in the moment of hydrohalite disappearance. The homogenisation temperatures ranged from + 170.4 to +322°C and the halite melting temperatures were between +161.2 and +290.7°C. Densities vary in a small interval, from 1.10 to 1.14 g/cm3. Salinities are in the range of 30.1-37.5 wt% NaCl eq. Contents of NaCl and CaCl2 are within 24.0-31.0 wt% and 8.1-16.5 wt%, respectively. However, with the increasing temperature, two modes of homogenisation were observed. In the first case, the halite crystal melted before the total homogenisation. And in the second case, the vapour bubble disappeared before melting of halite crystal. This allowed us to estimate minimal PT conditions of galena stage formation. Minimal temperature and pressure values are 292°C and 2.2 kbar.
Geochemical evolution of high-pH sodic salt pans in Central Otago, New Zealand
Published in New Zealand Journal of Geology and Geophysics, 2022
Dave Craw, Cathy Rufaut, Dhana Pillai, Gemma Kerr
The Na-sulphate mineral present in evaporites is dependent on the temperature and humidity at the time (Flatt 2002). Hence, daily and seasonal weather changes can cause rapid recrystallisation in situ, and local dissolution without a rain event on cool humid days. Similar processes can affect Na-carbonate mineralogy (Table 3; Jagniecki et al. 2015). Likewise, hydrohalite (NaCl.2H2O) can form from halite, and then decompose, under humid near-freezing temperature conditions (Braitsch 1971). These processes can contribute to localised differential mobility of evaporites on salt pans, and also can facilitate migration of the salts into, and out of, the underlying substrate to affect crust formation and structure (Figure 3D, H; Figure 7E, F).
A new approach to the solubility in aqueous salt solutions
Published in Chemical Engineering Communications, 2019
Elisabetta Arato, Cristina Moliner, Angelo Morro
The extent of a solubility of a substance is measured as the saturation concentration. Hence, of Figure 8 is just the solubility of salt, which is shown to vary from 0.231, at T = 252.3 K, to 0.283, at T = 374.5 K. The peritectic point P, between hydrohalite and halite, occurs at and T = 273.65 K.