Carbonic inclusions

Kerkhof, Alfons van den; Thiéry, Régis

doi:10.1016/s0024-4937(00)00038-4

Cited by 133 publications

(45 citation statements)

References 27 publications

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“…In some crys tals of the two-phase (LL) in clusions, cool ing caused nu cle ation of gas bub ble within the orig inal liq uid bub ble. This per fectly proves the pres ence of CO 2 in the liq uid phase (Sterner and Bodnar, 1991;Schmidt et al, 1995;Kirill and Gra ham, 1999;Bakker and Di a mond, 2000;Schmidt and Bodnar, 2000;Di a mond, 2001Di a mond, , 2003Van den Kerkhof and Thiéry, 2001). In such cases, ho mogeni sa tion tem per a tures (Th car ) var ied in a wide range (from -42 to 5.8°C), in di cat ing vari able den sity of CO 2 .…”

Section: Fluid Inclusions -Petrography and Microthermometric Datasupporting

confidence: 55%

Inclusions in anhydrite crystals from blue halite veins in the Kłodawa Salt Dome (Zechstein, Poland)

Toboła

2016

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The oc cur rence of both the blue and vi o let halites is one of the most in ter est ing phe nom ena in na ture. De spite nu mer ous labo ra tory and field works, their or i gin in nat u ral evaporitic en vi ron ments has not been sat is fac to rily ex plained. In the K³odawa Salt Dome (Zechstein, Cen tral Po land), blue or vi o let halites oc cur rel a tively fre quently. Their ac cu mu la tions dif fer in size and in ten sity of colours. In this pa per, pet ro log i cal fea tures of anhydrite crys tals de rived from one of the larg est out crops of the blue ha lite at the K³odawa Salt Mine are pre sented. Anhydrite is one of solid in clu sions en coun tered in blue-col oured halite crys tals. Spe cial at ten tion was paid to fluid in clu sions pres ent in this anhydrite. The microthermometric mea sure ments showed two di rec tions of ho mog e nisation, i.e., to wards the liq uid phase (LG®L, LL®L) or to wards the gas phase (LG®G). In the for mer case, the tem per a tures ranged from 174 to 513°C, whereas in the lat ter one, the val ues from 224 to 385°C were mea sured. The com po si tion of in clu sions is rel a tively vari able. We can ob serve trans par ent and opaque daugh ter min er als as well as CO 2 in the liq uid phase ac com pa nied by a vari able amount of meth ane or hy dro gen sul phide. These fea tures of inclu sions in di cate that anhydrite crys tals and, thus, blue ha lite were formed un der the in flu ence of hy dro ther mal con di tions. Ob ser va tions in the mine work ings com bined with pet ro log i cal stud ies en able to con clude that blue colouration of ha lite crystals is con trolled by three fac tors: a high tem per a ture, re duc ing con di tions and de fects in ha lite lat tice re lated to tec tonic stress.Key words: blue ha lite, hy dro ther mal en vi ron ment, salt domes, anhydrite, epigenetic salt.

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Section: Fluid Inclusions -Petrography and Microthermometric Datasupporting

confidence: 55%

Inclusions in anhydrite crystals from blue halite veins in the Kłodawa Salt Dome (Zechstein, Poland)

Toboła

2016

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“…The pressure-temperature trapping conditions of fluid inclusions can be constructed from the microthermometric data, in combination with mineral phase equilibrium, and Kerkhof and Thiéry (2001). As shown in Fig. 14, the trapping temperatures (270~390℃) and the pressures (100~400 MPa) were lower than the metamorphic P-T conditions of green schist-facies.…”

Section: Mineralizing P-t Conditions From Extremely Co 2 -Rich Fluidsmentioning

confidence: 99%

Carbonic fluids in the Hamadi gold deposit, Sudan: origin and contribution to gold mineralization

Cheng

Wang

et al. 2017

Can. J. Earth Sci.

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The Hamadi gold deposit is located in North Sudan, and occurs in the Neoproterozoic metamorphic strata of the Arabian–Nubian Shield. Two types of gold mineralization can be discerned: gold-bearing quartz veins and altered rock ores near ductile shear zones. The gold-bearing quartz veins are composed of white to gray quartz associated with small amounts of pyrite and other polymetallic sulfide minerals. Wall-rock alterations include mainly beresitization, epidotization, chloritization, and carbonatization. CO2-rich inclusions are commonly seen in gold-bearing quartz veins and quartz veinlets from gold-bearing altered rocks; these include mainly one-phase carbonic (CO2 ± CH4 ± N2) inclusions and CO2–H2O inclusions with CO2/H2O volumetric ratios of 30% to ∼80%. Laser Raman analysis does not show the H2O peak in carbonic inclusions. In quartz veins, the melting temperature of solid CO2 (Tm,CO2) of carbonic inclusions has a narrow range of −59.6 to −56.8 °C. Carbonic inclusions also have CO2 partial homogenization temperatures (Th,CO2) of −28.3 to +23.7 °C, with most of the values clustering between +4.0 and +20 °C; all of these inclusions are homogenized into the liquid CO2 state. The densities range from 0.73 to 1.03 g/cm3. XCH4 of carbonic fluid inclusions ranges from 0.004 to 0.14, with most XCH4 around 0.05. In CO2–H2O fluid inclusions, Tm,CO2 values are recorded mostly at around −57.5 °C. The melting temperature of clathrate is 3.8–8.9 °C. It is suggested that the lowest trapping pressures of CO2 fluids would be 100 to ∼400 MPa, on the basis of the Th,CO2 of CO2-bearing one-phase (LCO2) inclusions and the total homogenization temperatures (Th,tot) of paragenetic CO2-bearing two-phase (LCO2–LH2O) inclusions. For altered rocks, the Tm,CO2 of the carbonic inclusions has a narrow range of −58.4 to ∼−57.0 °C, whereas the Th,CO2 varies widely (−19 to ∼+29 °C). Most carbonic inclusions and the carbonic phases in the CO2–H2O inclusions are homogenized to liquid CO2 phases, which correspond to densities of 0.70 to ∼1.00 g/cm3. Fluid inclusions in a single fluid inclusion assemblage (FIA) have narrow Tm,CO2 and Th,CO2 values, but they vary widely in different FIAs and non-FIAs, which indicates that there was a wide range of trapping pressure and temperature (P–T) conditions during the ore-forming process in late retrograde metamorphism after the metamorphism peak period. The carbonic inclusions in the Hamadi gold deposit are interpreted to have resulted from unmixing of an originally homogeneous aqueous–carbonic mixture during retrogress metamorphism caused by decreasing P–T conditions. CO2 contributed to gold mineralization by buffering the pH range and increasing the gold concentration in the fluids.

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“…Nine curves in the diagram are isochores for the system CO 2 (After Van den Kerkhof and Thiéry, 2001), and the data above the isochors are Th ,CO2 of CO 2 fluids. The grey ellipse represents the P-T conditions of deformation of quartz obtained by X-ray petrofabric (Zang et al,2007), The blue and pink ellipses represent the P-T conditions of formation of biotite and garnet Zones , SR-Sarekoubu deposit, QX-Qiaxia deposit.…”

Section: Southern Chinese Altaidesmentioning

confidence: 99%

CO 2 -rich inclusions in vein gold–copper mineralization of the Sarekoubu–Qiaxia District, southern Altaides, China: Implication for ore genesis

Yang

Xing

et al. 2015

Journal of Geochemical Exploration

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Carbonic inclusions

Cited by 133 publications

References 27 publications

Inclusions in anhydrite crystals from blue halite veins in the Kłodawa Salt Dome (Zechstein, Poland)

Inclusions in anhydrite crystals from blue halite veins in the Kłodawa Salt Dome (Zechstein, Poland)

Carbonic fluids in the Hamadi gold deposit, Sudan: origin and contribution to gold mineralization

CO 2 -rich inclusions in vein gold–copper mineralization of the Sarekoubu–Qiaxia District, southern Altaides, China: Implication for ore genesis

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