Problems in Estimation of the Formation Depth of Hydrothermal Deposits by Data on Pressure of Mineralizing Fluidsстатья
Информация о цитировании статьи получена из
Web of Science,
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 5 мая 2015 г.
Аннотация:In this paper, the formation depth of hydrothermal deposits is proposed to be roughly estimated by data on pressure variations in fluid inclusions from maximum Pmax to minimum Pmin values, taking into account the restrictions to the physical limits of this range based on lithostatic and hydrostatic fluid pressure. Under the assumption of a regressive trend in the PT conditions throughout the geological history of the deposits, it is possible to estimate the minimum depth at the beginning of the mineralization process, using a Pmax value and lithostatic fluid pressure gradient (~260 bar/km), and the maximum depth at the completion of mineralization process, using a Pmin value and hydrostatic gradient (~100 bar/km). If the mineral deposition depth estimated from the values of Pmax and lithostatic fluid pressure gradient is consistent with the depth estimate from the values of Pmin and hydrostatic fluid pressure gradient, then the resulting depth estimates correspond to the deposit formation depth unchanged throughout the mineral deposition process. In case of
the ratio Pmax/Pmin > 2.6–3.0, the deposit is mineralized under variable depth coordinates with an upward movement of mineral deposition level, according to obtained estimates, over a depth range of up to >15 km. In case of the ratio Pmax/Pmin < 2.6, the data on fluid pressure variations does not allow making any definite conclusions on the trends in the deposit formation depth. In deposits with an upward movement of the mineral deposition level, the trends in depth variations based on fluid pressure data are in qualitative agreement with the data on minimum temperature Tmin recorded in deposit fluid inclusions under the assumption of its physical restriction to geothermal field values.