Thermodynamic modeling of hydrothermal plumes forming processes in a submarine discharge zone

Abstract

The main methods are considered and results of the modeling of the geochemical processes in submarine hydrothermal solutions of mid-ocean ridges discharge zones are analyzed. Initial materials for modeling were received at several sea expeditions, including operations at the Russian-French expedition SERPENTINE on RV «Pourquoi Pas?» (2007). For carrying out a computer thermodynamic modeling, hydro-geochemical and physicochemical models of a zone of hydrothermal discharge are created. Verification of model is carried out on the change of concentration of manganese in a hydrothermal plume. The prevailing forms of manganese migration in a plume are Mn2+, MnCl+, MnCl2. In a plume’s geochemical structure two zones are allocated: 1) high temperatures (350-100 °C), with the prevalence of the chloride complexes - buoyant plume; 2) low temperatures (100-2 °C), with the domination of a transfer in a form of free bivalent ion - lateral plume. The sulphate complex is observed in insignificant quantities (1,5 %) in a lateral plume, hydroxide - is stable at temperatures 325-125 °C and can be observed only in the buoyant plume. The results of the modeling almost completely correspond to the natural observations. A verification of the thermodynamic model testifies to her working capacity and allows to pass to the following stage of researches - to studying the geochemical dispersion nature of the main ore components in hydrothermal solutions - Fe, Cu, Zn, etc.

Keywords

• срединно-океанический хребет
• регрессионная модель
• термодинамическое моделирование
• гидротермальный раствор
• формы миграции