@article{fdi:010085359,
  title = {{I}nsights from mineral trace chemistry on the origin of {NYF} and mixed {LCT} plus {NYF} pegmatites and their mineralization at {M}angodara, {SW} {B}urkina {F}aso},
  author = {{B}onzi, {W}. {M}. {E}. and {V}an {L}ichtervelde, {M}arieke and {V}anderhaeghe, {O}. and {A}ndre-{M}ayer, {A}. {S}. and {S}alvi, {S}. and {W}enmenga, {U}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he {M}angodara district (southwestern of {B}urkina {F}aso, {W}est {A}frican {C}raton) consists of a regional-scale {E}burnean dome cored by granitoid-gneisses comprising rafts of migmatitic paragneisses and amphibolites of the {P}aleoproterozoic {B}irimian series. {T}he occurrence of rare metal-bearing pegmatites in diffuse contact with these migmatitic and granitoid gneisses suggests that they originated from the segregation of a residual melt of these partially molten hosts. {I}n this paper, we constrain the petrogenetic link between pegmatites and their hosts, and the mechanisms of rare metal fractionation in {L}ithium-{C}esium-{T}antalum ({LCT}) vs {N}iobium-{Y}ttrium-{F}luorine ({NYF}) petrogenetic signatures by the geochemistry of micas, apatite, columbite-group minerals, garnet, and zircon. {T}itanite-allanite pegmatites (containing titanite, allanite, epidote, zircon, and apatite as accessory minerals) and their evolved equivalent, apatite-zircon pegmatites (richer in apatite, lower {K}/{R}b and {F}e/{M}n ratio in biotite but {L}i-depleted) are poorly mineralized metaluminous pegmatites. {T}hey display a continuous evolution trend in {K}/{R}b and {F}e/{M}n in biotite and similar {REE} patterns in apatite, which favor an origin by segregation of residual melt within tonalitic-trondhjemitic gneiss in the core of the {M}angodara dome. {G}arnet-columbite pegmatites containing {REE}-bearing phosphates and {Z}r-{U}-{T}h-bearing metamict minerals are mixed {LCT} + {NYF} pegmatites. {T}heir micas, slightly enriched in {L}i, {LREE}-rich apatite, and {N}b-{T}a-{U}-rich garnet, are consistent with an origin by partial melting of a metasedimentary source, with dehydration of biotite (reservoir of {L}i, {R}b, {N}b) and dissolution of apatite-monazite (reservoir of {REE}). {A}patite crystals in one garnet-columbite pegmatite reveal an inherited {REE} signature typical of apatite-zircon pegmatite, which suggests mingling of a {LCT} pegmatite-forming melt with the residual melt derived from crystallization of metaluminous pegmatites. {G}arnet-{REE} pegmatites, containing ilmenite-pyrophanite and euxenite-aeschynite), are {NYF} pegmatites that should originate from melt segregation within granodioritic gneiss associated with breakdown/entrainment of amphibole (reservoir of {REE}, {Y}) and {LREE} segregation by allanite and phosphates in the source. {T}hese data show that the {LCT} vs {NYF} signature of pegmatites of the {M}angodara district results primarily from the chemical composition of the partially-molten source and the minerals involved in the partial melting reactions, which vary as a function of increasing depth (mica, phosphate, amphibole, garnet). {T}he trace-element signature of anatectic peraluminous pegmatite-forming melt might then be affected by mingling with residual {N}b-enriched metaluminous melt.},
  keywords = {{R}are metal-bearing pegmatite ; {W}est {A}frica {C}raton ; {G}eochemistry ; {M}icas ; {A}ccessory minerals ; {M}ixed {LCT} plus {NYF} pegmatites ; {BURKINA} {FASO} ; {MANGODARA}},
  booktitle = {},
  journal = {{M}ineralium {D}eposita},
  volume = {[{E}arly access]},
  numero = {},
  pages = {[30 p.]},
  ISSN = {0026-4598},
  year = {2022},
  DOI = {10.1007/s00126-022-01127-x},
  URL = {https://www.documentation.ird.fr/hor/fdi:010085359},
}