Limits...
Lithium isotope traces magmatic fluid in a seafloor hydrothermal system.

Yang D, Hou Z, Zhao Y, Hou K, Yang Z, Tian S, Fu Q - Sci Rep (2015)

Bottom Line: The δ(7)Li results vary from +4.5‰ to +13.8‰ for fluid inclusions and from +6.7‰ to +21.0‰ for the hosted gangue quartz(9 gangue quartz samples containing primary fluid inclusions).This δ(7)Li range, together with Li-O modeling , suggest that magmatic fluid played a significant role in the ore formation.This study demonstrates that Li isotope can be effectively used to trace magmatic fluids in a seafloor hydrothermal system and has the potential to monitor fluid mixing and ore-forming process.

View Article: PubMed Central - PubMed

Affiliation: Institute of Mineral Resources, CAGS, Beijing 100037, P. R. China.

ABSTRACT
Lithium isotopic compositions of fluid inclusions and hosted gangue quartz from a giant volcanogenic massive sulfide deposit in China provide robust evidence for inputting of magmatic fluids into a Triassic submarine hydrothermal system. The δ(7)Li results vary from +4.5‰ to +13.8‰ for fluid inclusions and from +6.7‰ to +21.0‰ for the hosted gangue quartz(9 gangue quartz samples containing primary fluid inclusions). These data confirm the temperature-dependent Li isotopic fractionation between hydrothermal quartz and fluid (i.e., Δδ(7)Liquartz-fluid = -8.9382 × (1000/T) + 22.22(R(2) = 0.98; 175 °C-340 °C)), which suggests that the fluid inclusions are in equilibrium with their hosted quartz, thus allowing to determine the composition of the fluids by using δ(7)Liquartz data. Accordingly, we estimate that the ore-forming fluids have a δ(7)Li range from -0.7‰ to +18.4‰ at temperatures of 175-340 °C. This δ(7)Li range, together with Li-O modeling , suggest that magmatic fluid played a significant role in the ore formation. This study demonstrates that Li isotope can be effectively used to trace magmatic fluids in a seafloor hydrothermal system and has the potential to monitor fluid mixing and ore-forming process.

No MeSH data available.


(a) Variation in δ7Li of the host quartz and fluid inclusions with the measured homogeneous temperatures. (b) Relationship of Li isotopic fractionation factor (△quartz-fluid) with homogeneous temperatures (1000/T) of fluid inclusions hosted in nine pure-quartz samples (containing primary fluid inclusions). All data from Table S1.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4561896&req=5

f2: (a) Variation in δ7Li of the host quartz and fluid inclusions with the measured homogeneous temperatures. (b) Relationship of Li isotopic fractionation factor (△quartz-fluid) with homogeneous temperatures (1000/T) of fluid inclusions hosted in nine pure-quartz samples (containing primary fluid inclusions). All data from Table S1.

Mentions: Fifty-three gangue quartz samples, collected across the main orebodies (Fig. 1) is divided into two groups: pure-quartz (n = 41) and quartz + sericite (n = 12). The former occurs in all three ore zones; the latter confines in the LSO and MSO. Li concentrations and isotopic compositions of 53 quartz samples and 29 fluid samples extraced from these host quartz are listed in Table S1 and plotted in Figs 2 and S1. The pure-quartz (n = 41) has Li concentrations of 0.03–1.61 μg/g and δ7Li varying from +4.1‰ to +22.5‰. The extracted fluids (n = 17) yield a range of δ7Li values from +3.7‰ to +15.0‰ (Fig. 2a). The quartz + sericite mixture has similar Li concentrations (0.02–1.75 μg/g) but lower δ7Li values (+0.8‰ to +4.2‰), the corresponding fluids (n = 12) have relatively high δ7Li varying from +1.3‰ to +10.2‰ (Fig. 2a). In general, the quartz samples from each ore zone have variable δ7Li values, laterally increasing outwards from a feeder zone (Table S1). The extracted fluids show average δ7Li values gradually increasing from +5.4‰ in the LSO to +9.8‰ in the UMO (Table S1).


Lithium isotope traces magmatic fluid in a seafloor hydrothermal system.

Yang D, Hou Z, Zhao Y, Hou K, Yang Z, Tian S, Fu Q - Sci Rep (2015)

(a) Variation in δ7Li of the host quartz and fluid inclusions with the measured homogeneous temperatures. (b) Relationship of Li isotopic fractionation factor (△quartz-fluid) with homogeneous temperatures (1000/T) of fluid inclusions hosted in nine pure-quartz samples (containing primary fluid inclusions). All data from Table S1.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4561896&req=5

f2: (a) Variation in δ7Li of the host quartz and fluid inclusions with the measured homogeneous temperatures. (b) Relationship of Li isotopic fractionation factor (△quartz-fluid) with homogeneous temperatures (1000/T) of fluid inclusions hosted in nine pure-quartz samples (containing primary fluid inclusions). All data from Table S1.
Mentions: Fifty-three gangue quartz samples, collected across the main orebodies (Fig. 1) is divided into two groups: pure-quartz (n = 41) and quartz + sericite (n = 12). The former occurs in all three ore zones; the latter confines in the LSO and MSO. Li concentrations and isotopic compositions of 53 quartz samples and 29 fluid samples extraced from these host quartz are listed in Table S1 and plotted in Figs 2 and S1. The pure-quartz (n = 41) has Li concentrations of 0.03–1.61 μg/g and δ7Li varying from +4.1‰ to +22.5‰. The extracted fluids (n = 17) yield a range of δ7Li values from +3.7‰ to +15.0‰ (Fig. 2a). The quartz + sericite mixture has similar Li concentrations (0.02–1.75 μg/g) but lower δ7Li values (+0.8‰ to +4.2‰), the corresponding fluids (n = 12) have relatively high δ7Li varying from +1.3‰ to +10.2‰ (Fig. 2a). In general, the quartz samples from each ore zone have variable δ7Li values, laterally increasing outwards from a feeder zone (Table S1). The extracted fluids show average δ7Li values gradually increasing from +5.4‰ in the LSO to +9.8‰ in the UMO (Table S1).

Bottom Line: The δ(7)Li results vary from +4.5‰ to +13.8‰ for fluid inclusions and from +6.7‰ to +21.0‰ for the hosted gangue quartz(9 gangue quartz samples containing primary fluid inclusions).This δ(7)Li range, together with Li-O modeling , suggest that magmatic fluid played a significant role in the ore formation.This study demonstrates that Li isotope can be effectively used to trace magmatic fluids in a seafloor hydrothermal system and has the potential to monitor fluid mixing and ore-forming process.

View Article: PubMed Central - PubMed

Affiliation: Institute of Mineral Resources, CAGS, Beijing 100037, P. R. China.

ABSTRACT
Lithium isotopic compositions of fluid inclusions and hosted gangue quartz from a giant volcanogenic massive sulfide deposit in China provide robust evidence for inputting of magmatic fluids into a Triassic submarine hydrothermal system. The δ(7)Li results vary from +4.5‰ to +13.8‰ for fluid inclusions and from +6.7‰ to +21.0‰ for the hosted gangue quartz(9 gangue quartz samples containing primary fluid inclusions). These data confirm the temperature-dependent Li isotopic fractionation between hydrothermal quartz and fluid (i.e., Δδ(7)Liquartz-fluid = -8.9382 × (1000/T) + 22.22(R(2) = 0.98; 175 °C-340 °C)), which suggests that the fluid inclusions are in equilibrium with their hosted quartz, thus allowing to determine the composition of the fluids by using δ(7)Liquartz data. Accordingly, we estimate that the ore-forming fluids have a δ(7)Li range from -0.7‰ to +18.4‰ at temperatures of 175-340 °C. This δ(7)Li range, together with Li-O modeling , suggest that magmatic fluid played a significant role in the ore formation. This study demonstrates that Li isotope can be effectively used to trace magmatic fluids in a seafloor hydrothermal system and has the potential to monitor fluid mixing and ore-forming process.

No MeSH data available.