title: [Raman spectroscopic study on the fluid effects in dissolution and phase transition mechanisms of gypsum].
abstract: Raman spectroscopic studies on the process of dissolution and phase transition of gypsum in different fluids were taken. Gypsum took phase transition to be anhydrite in the range from 170 degrees C to 190 degrees C in pure water, and no more change happened with decreasing temperature to room temperature. Gypsum took phase transition to be anhydrite in the range from 170 degrees C to 190 degrees C too in Na2 SO4 solution, but anhydrite can regain to be gypsum when temperature decreases to room temperature. The process of phase transition of gypsum in pure water is not reversible, but it happens in Na2 SO4 solution. The study shows that fluid effects can influence the dissolution and phase transition mechanisms of minerals and cannot be ignored.
authors.affiliation: Laboratory of Isotope Geology, MLR, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China. wangshixia83@163.com
authors.forename: Shi-xia
authors.initials: SX
authors.lastname: Wang
authors.forename: Hai-fei
authors.initials: HF
authors.lastname: Zheng