Formation of Fe rhodochrosite in a natural hydrothermal system from the aspect of thermodynamics

Abstract

The conditions of origin and stability in a natural hydrothermal system have been modeled thermodynamically on the basis of the chemical composition of rhodochrosite "rosettes" and reniform rhodochrosite from Stari Trg-Trepča. The changes in Gibbs free energy, enthalpy and entropy in the function of T p and ion concentration in the solution provided basis for the analysis. The results obtained indicate that in strong to moderate reduction conditions the formation of reniform rhodochrosite must have preceded the formation of rhodochrosite "rosettes".

Na osnovu hemijskog sastava, "rozeti" rodohrozita i bubrežastog rodohrozita iz Starog Trga-Trepča, izvršeno je termodinamičko modeliranje uslova nastanka i stabilnosti u prirodnom hidrotermalnom sistemu. Razmatranje je izvršeno na osnovu promene Gibbsove slobodne energije, entalpije i entropije u funkciji T, π i koncentracije jona u rastvoru. Dobijeni rezultati su pokazali da je prvo moralo doći do obrazovanja bubrežastog rodohrozita, a zatim do "rozeti" rodohrozita u jače do umereno redukcionim uslovima.