Advanced search
1 file | 6.37 MB Add to list

Mixing of magmatic-hydrothermal and metamorphic fluids and the origin of peribatholitic Sn vein-type deposits in Rwanda

(2018) ORE GEOLOGY REVIEWS. 101. p.481-501
Author
Organization
Abstract
The fluid sources of granite-related Sn-quartz vein deposits are commonly obscured by fluid mixing or fluid-rock interactions. As a result, fluid inclusions, minerals and isotopes in these veins indicate an intermediate composition between magmatic and metamorphic, but the degree of mixing between these endmembers is currently unquantified. This study presents a novel quantitative approach to assess the degree of mixing between magmatic-hydrothermal and external metamorphic fluids in the formation of peribatholitic Sn-quartz veins. In particular, fluid mixing in the Sn-mineralized Rwamagana-Musha-Ntunga pegmatite-quartz vein field in East Rwanda has been evaluated by the following four methods: quartz stable isotopes, muscovite geochemistry, fluid inclusion microthermometry and LA-ICP-MS, and geochemical modelling. The quartz stable isotope data (delta O-18: +13.1 to +15.8 parts per thousand V-SMOW; delta D: -27.6 to -59.7 parts per thousand V-SMOW) cannot uniquely differentiate between a metamorphic fluid origin or an initial magmatic hydrothermal fluid origin with subsequent metamorphic fluid mixing or host-rock interaction. However, granitophile element concentrations in magmatic muscovite from pegmatites and hydrothermal muscovite from associated Sn-quartz veins are equally high, indicating a close genetic link (Rb: 530-8740 ppm, Li: 110-1990 ppm, Sn: 87-810 ppm, Cs: 62-420 ppm). Primary H2O-CO2-N-2-NaCl medium saline magmatic fluid inclusions in quartz of pegmatites (similar to 12.7 wt% NaCleq) and H2O-CO2-(N-2)-NaCl low saline fluid inclusions in barren metamorphic quartz veins (similar to 4.9 wt% NaCleq) were analyzed by LA-ICP-MS. These results show an enrichment in Li, Rb, Sn and Cs for the magmatic fluid, while the metamorphic fluid is characterized by low granitophile element concentrations and high Sr and Ba contents. The expected Rb-Cs and Rb-Sn signature of the Sn-quartz vein muscovite was modelled using the measured fluid endmember compositions, confirming mixing between magmatic and metamorphic fluids in the formation of the veins. The quantification suggests that the hydrothermal Sn-quartz vein fluid contains 5-80% of an external metamorphic fluid component.
Keywords
Leucogranite mineralization, Pegmatites, Cassiterite, Quartz veins, Fluid mixing, Geochemical modelling, CENTRAL-IBERIAN ZONE, LA-ICP-MS, BEARING PEGMATITES, STABLE-ISOTOPE, GATUMBA AREA, U-PB, EXTREME FRACTIONATION, GRANITIC PEGMATITES, CENTRAL-AFRICA, SILICATE MELT

Downloads

  • (...).pdf
    • full text
    • |
    • UGent only
    • |
    • PDF
    • |
    • 6.37 MB

Citation

Please use this url to cite or link to this publication:

MLA
Van Daele, J, N Hulsbosch, Stijn Dewaele, et al. “Mixing of Magmatic-hydrothermal and Metamorphic Fluids and the Origin of Peribatholitic Sn Vein-type Deposits in Rwanda.” ORE GEOLOGY REVIEWS 101 (2018): 481–501. Print.
APA
Van Daele, J, Hulsbosch, N., Dewaele, S., Boiron, M.-C., Piessens, K., Boyce, A., & Muchez, P. (2018). Mixing of magmatic-hydrothermal and metamorphic fluids and the origin of peribatholitic Sn vein-type deposits in Rwanda. ORE GEOLOGY REVIEWS, 101, 481–501.
Chicago author-date
Van Daele, J, N Hulsbosch, Stijn Dewaele, M-C Boiron, K Piessens, A Boyce, and Ph Muchez. 2018. “Mixing of Magmatic-hydrothermal and Metamorphic Fluids and the Origin of Peribatholitic Sn Vein-type Deposits in Rwanda.” Ore Geology Reviews 101: 481–501.
Chicago author-date (all authors)
Van Daele, J, N Hulsbosch, Stijn Dewaele, M-C Boiron, K Piessens, A Boyce, and Ph Muchez. 2018. “Mixing of Magmatic-hydrothermal and Metamorphic Fluids and the Origin of Peribatholitic Sn Vein-type Deposits in Rwanda.” Ore Geology Reviews 101: 481–501.
Vancouver
1.
Van Daele J, Hulsbosch N, Dewaele S, Boiron M-C, Piessens K, Boyce A, et al. Mixing of magmatic-hydrothermal and metamorphic fluids and the origin of peribatholitic Sn vein-type deposits in Rwanda. ORE GEOLOGY REVIEWS. 2018;101:481–501.
IEEE
[1]
J. Van Daele et al., “Mixing of magmatic-hydrothermal and metamorphic fluids and the origin of peribatholitic Sn vein-type deposits in Rwanda,” ORE GEOLOGY REVIEWS, vol. 101, pp. 481–501, 2018.
@article{8570378,
  abstract     = {The fluid sources of granite-related Sn-quartz vein deposits are commonly obscured by fluid mixing or fluid-rock interactions. As a result, fluid inclusions, minerals and isotopes in these veins indicate an intermediate composition between magmatic and metamorphic, but the degree of mixing between these endmembers is currently unquantified. This study presents a novel quantitative approach to assess the degree of mixing between magmatic-hydrothermal and external metamorphic fluids in the formation of peribatholitic Sn-quartz veins. In particular, fluid mixing in the Sn-mineralized Rwamagana-Musha-Ntunga pegmatite-quartz vein field in East Rwanda has been evaluated by the following four methods: quartz stable isotopes, muscovite geochemistry, fluid inclusion microthermometry and LA-ICP-MS, and geochemical modelling. 
The quartz stable isotope data (delta O-18: +13.1 to +15.8 parts per thousand V-SMOW; delta D: -27.6 to -59.7 parts per thousand V-SMOW) cannot uniquely differentiate between a metamorphic fluid origin or an initial magmatic hydrothermal fluid origin with subsequent metamorphic fluid mixing or host-rock interaction. However, granitophile element concentrations in magmatic muscovite from pegmatites and hydrothermal muscovite from associated Sn-quartz veins are equally high, indicating a close genetic link (Rb: 530-8740 ppm, Li: 110-1990 ppm, Sn: 87-810 ppm, Cs: 62-420 ppm). Primary H2O-CO2-N-2-NaCl medium saline magmatic fluid inclusions in quartz of pegmatites (similar to 12.7 wt% NaCleq) and H2O-CO2-(N-2)-NaCl low saline fluid inclusions in barren metamorphic quartz veins (similar to 4.9 wt% NaCleq) were analyzed by LA-ICP-MS. These results show an enrichment in Li, Rb, Sn and Cs for the magmatic fluid, while the metamorphic fluid is characterized by low granitophile element concentrations and high Sr and Ba contents. The expected Rb-Cs and Rb-Sn signature of the Sn-quartz vein muscovite was modelled using the measured fluid endmember compositions, confirming mixing between magmatic and metamorphic fluids in the formation of the veins. The quantification suggests that the hydrothermal Sn-quartz vein fluid contains 5-80% of an external metamorphic fluid component.},
  author       = {Van Daele, J and Hulsbosch, N and Dewaele, Stijn and Boiron, M-C and Piessens, K and Boyce, A and Muchez, Ph},
  issn         = {0169-1368},
  journal      = {ORE GEOLOGY REVIEWS},
  keywords     = {Leucogranite mineralization,Pegmatites,Cassiterite,Quartz veins,Fluid mixing,Geochemical modelling,CENTRAL-IBERIAN ZONE,LA-ICP-MS,BEARING PEGMATITES,STABLE-ISOTOPE,GATUMBA AREA,U-PB,EXTREME FRACTIONATION,GRANITIC PEGMATITES,CENTRAL-AFRICA,SILICATE MELT},
  language     = {eng},
  pages        = {481--501},
  title        = {Mixing of magmatic-hydrothermal and metamorphic fluids and the origin of peribatholitic Sn vein-type deposits in Rwanda},
  url          = {http://dx.doi.org/10.1016/j.oregeorev.2018.07.020},
  volume       = {101},
  year         = {2018},
}

Altmetric
View in Altmetric
Web of Science
Times cited: