碱交代与铁矿形成的地球化学机理探讨

GEOCHEMICAL MECHAMISM OF ALKALI METASOMATISM AND THE FORMATION OF IRON DEPOSITS

Discussions are given to the processes of albitization and iron activation during the formation of iron deposits, the transportation and hydrolysis of iron, chemical reactions characteristic of wall rock alteration responsible for the localization of iron deposits, the dynamic factors affecting these reactions as well as the systematic pH variation of ore forming solutions. A metasomatic series of Na→Ca→Fe is noticed when diorite and dark minerals + anorthite + quartz are reacted with 1--3N NaCl solution at 400-500℃。Hydrolysis of FeCl3 is experimentally studied as a function of temperature and pressure.The authors suggest that the pH of ore forming solution varies in the direction of alkalic→ intermediate→acid→intermediate→alkalic from eariler to later stages.

Discussions are given to the processes of albitization and iron activation during the formation of iron deposits, the transportation and hydrolysis of iron, chemical reactions characteristic of wall rock alteration responsible for the localization of iron deposits, the dynamic factors affecting these reactions as well as the systematic pH variation of ore forming solutions. A metasomatic series of Na→Ca→Fe is noticed when diorite and dark minerals + anorthite + quartz are reacted with 1-3N NaCl solution at 400-500℃. Hydrolysis of PeCl2 is experimentally studied as a function of temperature and pressure. The authors suggest that the pH of ore forming solution varies in the direction of alkalic → intermediate → acid → intermediate→ alkalic from eariler to later stages.