Role of fluid mixing and wallrock sulfidation in gold mineralization at the Semna mine area, central Eastern Desert of Egypt: Evidence from hydrothermal alteration, fluid inclusions and stable isotope data

2008 ◽  
Vol 34 (4) ◽  
pp. 580-596 ◽  
Author(s):  
Basem Zoheir ◽  
Ahmed Akawy ◽  
Imbarak Hassan
Keyword(s):  
Stable Isotope ◽  
Hydrothermal Alteration ◽  
Fluid Inclusions ◽  
Gold Mineralization ◽  
Eastern Desert ◽  
Fluid Mixing ◽  
Mine Area ◽  
Central Eastern Desert ◽  
Stable Isotope Data

Manganoan fayalite and products of its alteration from the Strzegom pegmatites, Poland

1989 ◽  
Vol 53 (371) ◽  
pp. 315-325 ◽  
Author(s):  
J. Janeczek
Keyword(s):  
Hydrothermal Alteration ◽  
Fluid Inclusions ◽  
Iron Hydroxide ◽  
Silicate Phase ◽  
Second Stage ◽  
Multi Stage ◽  
Composite Mixture ◽  
Quartz Aggregates ◽  
Lower Silesia

AbstractNodules of manganoan fayalite occur in schlieren pegmatities in the vicinity of Strzegom, Lower Silesia. The fayalite, Na0.02(Fe1.812+Mn0.16Mg 0.03)Si0.99O4, is unzoned and non pleochroic. 2Va = 42° a 4.826(3), b 10.500(2), c 6.102(2) A, d130obs. = 2.83 Å, d130calc. = 2.833 Å, D = 4.35 g cm-3, Dcalc. = 4.353 g cm-3. The role of Na+ ions in the fayalite chemistry is discussed. The fayalite underwent multi-stage hydrothermal alteration beginning at the highest temperature (440°C) of homogenization of gaseous-fluid inclusions in quartz adjacent to the fayalite grains. Increase in fO2 and then in PH2O resulted in the formation of magnetite-quartz and Mn-grunerite-magnetite-quartz aggregates within the fayalite grains. The fayalite is mantled by a Mn-greenalite-magnetite rim, Mn-grunerite-magnetite-Mn-minnesotaite zone in a stilpnomelane or greenalite-rich groundmass. The minnesotaite is believed to have formed at the expense of grunerite. Stilpnomelane, the most abundant silicate phase in the rim, is the product of biotite and presumably greenalite alteration at the second stage of increasing Na activity (the crystallization of cleavelandite) in the pegmatites. The fayalite is also heavily altered to iddingsite—a composite mixture of amorphous FeOOH and silica. The iron-hydroxide recrystallized partially to poorly-crystalline goethite.

Genesis of two different types of gold mineralization in the Linglong gold field, China: Constrains from geology, fluid inclusions and stable isotope

2015 ◽  
Vol 65 ◽  
pp. 643-658 ◽  
Author(s):  
Bo-Jie Wen ◽  
Hong-Rui Fan ◽  
M. Santosh ◽  
Fang-Fang Hu ◽  
Franco Pirajno ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Fluid Inclusions ◽  
Gold Mineralization ◽  
Different Types
Sign in / Sign up

Export Citation Format

Share Document