@article{fdi:010070894,
  title = {{A}ge and origin of the tsavorite and tanzanite mineralizing fluids in the neoproterozoic {M}ozambique metamorphic belt},
  author = {{F}eneyrol, {J}. and {G}iuliani, {G}aston and {D}emaiffe, {D}. and {O}hnenstetter, {D}. and {F}allick, {A}. {E}. and {D}ubessy, {J}. and {M}artelat, {J}. {E}. and {R}akotondrazafy, {A}. {F}. {M}. and {O}mito, {E}. and {I}chan{G}'{I}, {D}. and {N}yamai, {C}. and {W}amunyu, {A}. {W}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he genetic model previously proposed for tsavorite-(and tanzanite-) bearing mineralization hosted in the {N}eoproterozoic {M}etamorphic {M}ozambique {B}elt (stretching from {K}enya through {T}anzania to {M}adagascar) is refined on the basis of new {S}m-{N}d age determinations and detailed {S}r-{O}-{S} isotope and fluid-inclusion studies. {T}he deposits are hosted within meta-sedimentary series composed of quartzites, graphitic gneisses, calc-silicate rocks intercalated with meta-evaporites, and marbles. {T}savorite occurs either in nodules (also called "boudins') oriented parallel to the metamorphic foliation in all of the deposits in the metamorphic belt or in quartz veins and lenses located at the hinges of anticlinal folds ({L}elatema fold belt and {R}uangwa deposits, {T}anzania). {G}em tanzanite occurs in pockets and lenses in the {L}elatema fold belt of northern {T}anzania. {T}he {S}m-{N}d isotopic data for tsavorites and tanzanites hosted in quartz veins and lenses from {M}erelani demonstrate that they formed at 600 {M}a, during the retrograde metamorphic episode associated with the {E}ast {A}frican {O}rogeny. {T}he tsavorites hosted in nodules do not provide reliable ages: their sedimentary protoliths had heterogeneous compositions and their {S}m-{N}d system was not completely rehomogenized, even at the local scale, by the fluid-absent metamorphic recrystallization. {T}he initial {S}r-87/(86) {S}r isotopic ratios of calcite from marble and tanzanites from {M}erelani fit with the strontium isotopic composition of {N}eoproterozoic marine carbonates. {S}eawater sediment deposition in the {M}ozambique {O}cean took place around 720 {M}a. {T}he quartz-zoisite {O}-isotopic thermometer indicates a temperature of formation for zoisite between 385 and 448 degrees {C}. {T}he sulfur isotopic composition of pyrite (between -7.8 and -1.3% {V}-{CDT}) associated with tsavorite in the {L}elatema fold belt deposits suggests the contribution of reduced marine sulfate. {T}he sulfur in pyrite in the marbles was likely derived from bacterial sulfate reduction which produced {H}2{S}. {F}luid inclusion data from tsavorite and tanzanite samples from the {M}erelani mine indicate the presence of a dominant {H}2{S}-{S}-8 +/-({CH}4)+/-({N}-2)+/-({H}2{O})-bearing fluid. {I}n the deposits in {K}enya and {M}adagascar, the replacement of sulfate by tsavorite in the nodules and the boron isotopic composition of tourmaline associated with tsavorite are strong arguments in favor of the participation of evaporites in garnet formation.},
  keywords = {{N}eoproterozoic {M}etamorphic {M}ozambique {B}elt ; tsavorite ; tanzanite ; {S}m/{N}d ; dating ; {S}r-{O}-{S}-isotopes ; fluid inclusion ; origin of the fluids. ; {KENYA} ; {TANZANIE} ; {MADAGASCAR}},
  booktitle = {},
  journal = {{C}anadian {M}ineralogist},
  volume = {55},
  numero = {4},
  pages = {763--786},
  ISSN = {0008-4476},
  year = {2017},
  DOI = {10.3749/canmin.1600085},
  URL = {https://www.documentation.ird.fr/hor/fdi:010070894},
}