@article{fdi:010081639,
  title = {{K}arelianite and vanadian phlogopite from the merelani hills gem zoisite deposits, {T}anzania},
  author = {{G}iuliani, {G}aston and {O}hnenstetter, {D}. and {P}alhol, {F}. and {F}eneyrol, {J}. and {B}outroy, {E}. and {B}oissezon de, {H}. and {L}homme, {T}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he {M}erelani deposits of gem-quality vanadian zoisite ("tanzanite") in {T}anzania occur in {P}roterozoic vanadium-rich sedimentary series metamorphosed to the amphibolite facies. {T}he gem-bearing assemblage consists of quartz, sulfides, graphite and "tanzanite" occurring in hydrothermal veins deposited in hydrothermally altered graphitic gneisses, marbles and calc-silicates. {T}wo rare vanadian oxide and silicate minerals crystallize on the margins of pyrite and {V}-bearing pyrrhotite lenses, which are cross-cut by graphite-"tanzanite"-bearing quartz veins. {K}arelianite has a nearly pure end-member composition in the karelianite-eskolaite solid-solution series, with 93 to 96 wt% {V}2{O}3. {V}anadian phlogopite closely associated with karelianite has high {M}g{O} (18.5 to 22.8 wt%), {F} (1.2 to 2.0 wt%) and {T}i{O}2 (up to 1.3 wt%). {T}he {V}2{O}3 content varies between 4.2 and 10.9 wt%. {T}he protolith of the host rock that contains the mineralization is a black shale; the hydrothermal graphite has a delta {C}-13 equal to-24.0%, which indicates a sedimentary source rich in organic matter. {D}uring hydrothermal alteration, {V} and {C}r were scavenged by fluids from the graphitic gneisses, and fixed by the oxide and silicates. {T}extural evidence of dissolution of karelianite indicates that vanadium was remobilized by the hydrothermal fluid during the formation of late-stage vanadian zoisite ("tanzanite"), found in veinlets that cross-cut both sulfides and vanadium-bearing minerals.},
  keywords = {karelianite ; vanadian phlogopite ; tanzanite ; graphitic gneiss ; {M}erelani ; {M}ozambique {B}elt ; {T}anzania},
  booktitle = {},
  journal = {{C}anadian {M}ineralogist},
  volume = {46},
  numero = {{P}art 5},
  pages = {1183--1194},
  ISSN = {0008-4476},
  year = {2008},
  DOI = {10.3749/canmin.46.5.1183},
  URL = {https://www.documentation.ird.fr/hor/fdi:010081639},
}