Sources of the fluids for metasomatic magnesite of Ismakaevo deposit in the South Ural province (thermokryometry of fluid inclusions)

• Main Authors: M. T. Krupenin, A. A. Garaeva
• Format: Article
• Language: English
• Published: A.N. Zavaritsky Institute of Geology and Geochemistry 2015-04-01
• Series: Литосфера
• Subjects: магнезит; кварц; рассолы; микрокриометрия флюидных включений; magnesite; quartz; brines; microkryometry of fluid inclusions
• Online Access: https://www.lithosphere.ru/jour/article/view/188

Bittern brine nature of fluid inclusions in magnesite of Ismakaevo deposits are confirmed not only by data of Cl-Br ion systematics, but also by methods of microthermometry. The mean value of salinity of inclusions in magnesite is 23.6 wt % NaCl eqiv. (variations 20.7-25.8). In the salt composition of the inclusions, according to the eutectic temperature at microkryometry study (-50.8...-56.2°C), dominate magnesium, sodium and calcium chlorides. Homogenization temperature of two-phase inclusions occurs within the interval 184-279°C (average 224°C). High salinity fluid inclusions (24.1-24.9 wt % NaCl eqiv.) and stable temperature homogenization (216-245°C) are observed also in metasomatic fine-grained (icy) quartz, syngenetic with magnesite. Giant-grained milky-white later quartz has a lower salinity (11.5-17.1 wt %) and homogenization temperature (169-245°C).