Palaeofluid flow in siliciclastic Lower Carboniferous rocks: Evidence from stable isotopes and fluid inclusions, Rhenohercynian Zone, Czech Republic

Author(s):  
Jan Kucera ◽  
Klàra Kucerovà-Charvàtovà ◽  
Phillipe Muchez ◽  
Walter Prochaska
2016 ◽  
Vol 23 (1-2) ◽  
Author(s):  
Michaela Kotlánová ◽  
Zdeněk Dolníček

Origin and chemical composition of fluids of hydrothermal ore veins at historical deposit Zlatý důl near Hlubočky (Lower Carboniferous of the Nízký Jeseník Upland) were studied using petrography, microthermometry and crush-leach analysis of fluid inclusions and analysis of stable isotopes of oxygen and carbon in carbonates, oxygen in quartz and sulphur in sulphides. Studied mineralization has epithermal and partly mesothermal character (Th = < 50 to 293 °C). The H2O-NaCl-CaCl2 system is mostly enclosed in the primary fluid inclusions in minerals of post-Variscan ore veins. These fluids had low to medium homogenization temperatures (68 to 293 °C) and moderate to high salinities (19–27 wt. % NaCl eq.). In contrast, low to moderate salinity (0–10 wt. % NaCl eq.) fluids of the system H2O-NaCl-KCl-(MgCl2-FeCl2) with low homogenization temperatures (< 50 to 110 °C) were enclosed in secondary fluid inclusions. The main source of water was probably evaporated seawater for older fluids. The source of carbon was in carbon of the homogenized Earth’s crust and partly in carbon of organic matter. Meteoric water is the main source for younger fluids. Origin of sulphur of sulphides is in the surrounding Lower Carboniferous sediments (shales). The high content of SO4 in fluids hosted by Fe-rich dolomite suggests the origin of the fluids in the evaporated Permian basins. Studied older quartz-galena vein is probably Variscan in age. Genetically similar mineralization can be found also at other localities in the Moravo-Silesian Lower Carboniferous (Culm, siliciclastics of the Lower Carboniferous age).


2014 ◽  
Vol 57 ◽  
pp. 351-362 ◽  
Author(s):  
Jinjie Yu ◽  
Jingwen Mao ◽  
Fuxiong Chen ◽  
Yonghui Wang ◽  
Linrui Che ◽  
...  

2017 ◽  
Vol 27 (6) ◽  
pp. 1363-1373 ◽  
Author(s):  
Jian-guo ZHANG ◽  
Yong-jun SHAO ◽  
Cheng WANG ◽  
Zhong-fa LIU ◽  
Yi-qu XIONG

1996 ◽  
Vol 60 (402) ◽  
pp. 813-819 ◽  
Author(s):  
Philippe Muchez ◽  
Marek Slobodnik

AbstractFerroan and non-ferroan calcites occur in fractures in the Lower Carboniferous of the Variscan foreland of southern Belgium. These fractures post-date the Variscan orogeny and the calcites have a telogenetic origin. The non-ferroan calcites formed by recrystallization of the ferroan calcites. Two types of monophase aqueous fluid inclusions are present in the ferroan calcite cement. Although both types of inclusions formed at a temperature not exceeding 50°C, one type contains a moderately saline fluid (3.6–16.3 eq. wt.% NaCl) and the other type fresh water (Tm ice = 0°C). The fluid inclusions in the non-ferroan calcite also contain fresh water.Detailed petrography of the fluid inclusions indicate that the fresh water migrated through the crystals along opened cleavage planes and microfractures. Therefore, they have a secondary origin. The recrystallization of the ferroan calcites to non-ferroan calcites occurred in this fresh water. The saline fluid inclusions are not related to the above mentioned microstructures and although their origin remains unknown, they could represent the ambient fluid from which the ferroan calcites precipitated. The study of the relationship between the occurrence of fluid inclusions and the microstructures seems promising for the identification of fluid inclusions representing post mineral formation fluid and temperature conditions in calcite cements.


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