Литосфера (Apr 2015)
Sources of the fluids for metasomatic magnesite of Ismakaevo deposit in the South Ural province (thermokryometry of fluid inclusions)
Abstract
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).
