ON THE BOROSILICATE FORMATION CONDITIONS IN THE PROCESS OF HALOGENESIS

A quantitative estimate of the datolite and danburite formation model in the interaction of buried brine with saltbearing series of the salt basin. The extimate was carried out by use of thermodynamic analysis. The formation conditions of named borosilicates are as following: 1) calcium enrichment of buried solutions in the process of direct metamo rphism; 2) silica saturation of solutions in the leacing of amorphous silica from the country sediments; 3) certain pH values of the solutio ns: not below 5.0-5.5 for datolite formation and not below 4.3-5.0 for danburite, formation. All these conditions are practically always sat isfied in nature, thus the borosilicates of the saltbearing series cou ld be considered as a natural product of salt rock diagenesis.