Coupled hydrodynamic and thermodynamic model for a convecting hydrothermal system: 1. The marker method of modelingстатья
Информация о цитировании статьи получена из
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 28 мая 2015 г.
Аннотация:A combined model was developed for a convecting hydrothermal system in a mid-ocean ridge, The modeling includes two computation stages, At the first stage, paths are calculated for the movement of "markers" that are point-sized portions of solutions with given initial coordinates, Temperature, pressure, and filtration rate are determined for each part of the marker paths, Ar. the second stage, the compositions of metasomatic mineral assemblages and equilibrium hydrothermal solutions are calculated for each part of the system. Temperature and pressure are included directly into the thermodynamic calculations, while filtration rate is used to estimate the intensity of interaction between the solution and the host rock. The hydrodynamic part of the model uses the numerical solution of Darcy's law and heat transfer equations by the finite-element method, The thermodynamic stage utilizes the technique of a flow-type stepwise reactor, Local equilibrium between solution and rock was calculated for each step of this reactor. The modeling demonstrated that a convection cell forms in the hydrothermal system with a wide region of descending flow and a narrow ascending parcel in the fracture zone above the intrusive body. Near the ascending limb, there is a region of circular flow, but it is non-steady state and degenerates with time, Isotherms in the system are near parallel to the contact of the magma chamber, The rock/solution ratio increases in the contact part of the system and is highest above the top of the magma chamber, The calculated distribution of metasomatic minerals is similar to that observed in ophiolite sequences. The time required for a portion of seawater to pass through the convection system was estimated to be about 1000 years for the whole system and only n x 10 years for the segment with active solution-rock interaction.