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Evolution of mineralizing fluids of greisen and fluorite veins, evidence from fluid inclusions

Research Authors
Hany H. El Hadek, Mohamed Abdel-Moneim Mohamed,Wagih W. Bishara, Galal H. El Habaak, Kamal A. Ali
Research Abstract

The late-Proterozoic Homrit Waggat granite complex contains Sn-F bearing quartzmuscovite
greisen zone as well as fluorite veins. Fluid inclusions study in quartz and
fluorite from greisen indicates the same fluid inclusion types. Fluid inclusions trapped in
greisenized granite are represented mainly by two–phase (L+V) aqueous and immiscible
three-phase (H2O-CO2) inclusions which probably trapped from one homogeneous fluid
(H2O˗CO2˗NaCl) due to immiscibility process. Two-phase aqueous inclusions (type 1)
are represented by three generations (subtype 1a, subtype 1b and subtype 1c). Immiscible
three-phase inclusions are conformable and coexisting with the three generations of
aqueous inclusions. Based on paragenetic distribution of the inclusions, subtype 1a and
subtype 2a are primary, subtype 1b and 2b are pseudosecondary, while subtype 1c and 2c
are secondary distributed. Microthermometric results for the first generation (subtypes 1a
and 2a) inclusions revealed that the greisenization probably starts at temperature >
330°C. Greisenization as well as cassiterite deposits probably continuous with
decreasing temperature (330°C - 270°C) and pressure estimated between 1.4 kb and 0.65
kb. Subtypes 1b and 2b as well as fluorite deposits may be taken place due to dilution at
temperature and pressure (260°C - 180°C and 536 - 441 bars). The latest fluid generation
is represented by high saline poly-phase, two-phase (subtype 1c) and mono-phase
aqueous inclusions. Such coexistence of inclusions is an evidence of boiling. In fluorite
veins only primary two-phase aqueous inclusions were observed. The minimum
pressures of trapping are between 181 and 212 bars at temperatures between 140°C and
200°C

Research Department
Research Journal
International Journal of Geophysics and Geochemistry
Research Publisher
American Association for Science and Technology
Research Rank
1
Research Vol
(5)3
Research Website
http://www.aascit.org/journal/ijgg
Research Year
2016
Research Pages
49-56