@article{fdi:010060328,
  title = {{N}ew aspects and perspectives on tsavorite deposits},
  author = {{F}eneyrol, {J}. and {G}iuliani, {G}aston and {O}hnenstetter, {D}. and {F}allick, {A}. {E}. and {M}artelat, {J}. {E}. and {M}onie, {P}. and {D}ubessy, {J}. and {R}ollion-{B}ard, {C}. and {L}e {G}off, {E}. and {M}alisa, {E}. and {R}akotondrazafy, {A}. {F}. {M}. and {P}ardieu, {V}. and {K}ahn, {T}. and {I}changi, {D}. and {V}enance, {E}. and {V}oarintsoa, {N}. {R}. and {R}anatsenho, {M}. {M}. and {S}imonet, {C}. and {O}mito, {E}. and {N}yamai, {C}. and {S}aul, {M}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}savorite, the vanadian variety of green grossular, is a high value economic gemstone. {I}t is hosted exclusively in the metasedimentary formations from the {N}eoproterozoic {M}etamorphic {M}ozambique {B}elt. {T}he deposits are mined in {K}enya, {T}anzania and {M}adagascar and other occurrences are located in {P}akistan and {E}ast {A}ntarctica. {T}hey are located within metasomatized graphitic rocks such as graphitic gneiss and calc-silicates, intercalated with meta-evaporites. {T}savorite is found as primary deposits either in nodule (type {I}) or in quartz vein (type {II}), and in placers (type {III}). {T}he primary mineralizations (types {I} and {II}) are controlled by lithostratigraphy and/or structure. {F}or the {A}frican occurrences, the protoliths of the host-rocks were deposited at the beginning of the {N}eoproterozoic within a marine coastal sabkha environment, located at the margin of the {C}ongo-{K}alahari cratons in the {M}ozambique {O}cean. {D}uring the {E}ast {A}frican-{A}ntarctican {O}rogeny, the rocks underwent high amphibolite to granulite fades metamorphism and the formation of tsavorite deposits occurred between 650 and 550 {M}a. {T}he nodules of tsavorite were formed during prograde metamorphism, calcium coming from sulphates and carbonates, whereas alumina, silicates, vanadium and chromium probably came from clays and chlorite. {T}he veins were formed during the deformation of the metasedimentary platform units which experienced shearing, leading to the formation of fault-filled veins. {M}etasomatism developed during retrograde metamorphism. {T}he metasedimentary sequences are characterized by the presence of evaporitic minerals such as gypsum and anhydrite, and scapolite. {E}vaporites are essential as they provide calcium and permit the mobilization of all the chemical elements for tsavorite formation. {T}he {H}2{S}-{S}-8 metamorphic fluids characterized in primary fluid inclusions of tsavorites and the delta {B}-11 values of coeval dravite confirm the evaporitic origin of the fluids. {T}he {V}2{O}3 and {C}r2{O}3 contents of tsavorite range respectively from 0.05 to 7.5 wt.%, while their delta {O}-18 values are in the range of 9.5-21.1 parts per thousand. {T}he genetic model proposed for tsavorite is metamorphic, based on chemical reactions developed between an initial assemblage composed of gypsum and anhydrite, carbonates and organic matter deposited in a sabkha-like sedimentary basin.},
  keywords = {{N}eoproterozoic {M}etamorphic {M}ozambique ; {B}elt ; {T}savorite ; {G}raphitic ; gneiss ; {E}vaporites ; {M}etasomatism ; {G}enetic model},
  booktitle = {},
  journal = {{O}re {G}eology {R}eviews},
  volume = {53},
  numero = {},
  pages = {1--25},
  ISSN = {0169-1368},
  year = {2013},
  DOI = {10.1016/j.oregeorev.2013.01.016},
  URL = {https://www.documentation.ird.fr/hor/fdi:010060328},
}