@article{fdi:010044073,
  title = {{M}arble-hosted ruby deposits from {C}entral and {S}outheast {A}sia : towards a new genetic model},
  author = {{G}arnier, {V}. and {G}iuliani, {G}aston and {O}hnenstetter, {D}. and {F}allick, {A}. {E}. and {D}ubessy, {J}. and {B}anks, {D}. and {V}inh, {H}. {Q}. and {L}homme, {T}. and {M}aluski, {H}. and {P}echer, {A}. and {B}akhsh, {K}. {A}. and {V}an {L}ong, {P}. and {T}rinh, {P}. {T}. and {S}chwarz, {D}.},
  editor = {},
  language = {{ENG}},
  abstract = {{M}arble-hosted ruby deposits represent the most important source of colored gemstones from {C}entral and {S}outh {E}ast {A}sia. {T}hese deposits are located in the {H}imalayan mountain belt which developed during {T}ertiary collision of the {I}ndian plate northward into the {E}urasian plate. {T}hey are spatially related to granitoid intrusions and are contained in platform carbonates series that underwent high-grade meta morph ism. {A}ll occurrences are located close to major tectonic features formed during {H}imalayan orogenesis, directly in suture zones in the {H}imalayas, or in shear zones that guided extrusion of the {I}ndochina block after the collision in {S}outh {E}ast {A}sia. {A}r-{A}r dating of micas syngenetic with ruby and {U}-{P}b dating of zircon included in ruby gives evidence that these deposits formed during {H}imalayan orogenesis, and the ages document the extensional tectonics that were active, from {A}fghanistan to {V}ietnam, between the {O}ligocene and the {P}liocene. {T}he petrography shows that ruby-bearing marbles formed in the amphibolite facies ({T}=610 to 790 degrees {C} and {P}-6 kbar). {A} fluid inclusion {S}tudy defines the conditions of gem ruby formation during the retrograde metamorphic path (620<{T}<670 degrees {C} and 2.6<{P}<3.3 kbar) for the deposits of {J}egdalek, {H}unza and northern {V}ietnam. {W}hole rock analyses of non-ruby-bearing marbles indicate that they contain enough aluminum and chromiferous elements to produce all the ruby crystals that they contain. {I}n addition, ({C}, {O})-isotopic analyses of carbonates from the marbles lead to the conclusion that the marbles acted as a metamorphic closed fluid system that were not infiltrated by externally-derived fluids. {T}he carbon isotopic composition of graphite in marbles reveals that it is of organic origin and that it exchanged {C}-isotopes with the carbonates during metamorphism. {M}oreover, the {O}-isotopic composition {O}f ruby was buffered by metamorphic {CO}2 released during devolatilisation of marble and the {H}-isotopic composition of mica is consistent with a metamorphic origin for water in equilibrium with the micas. {T}he ({C}, 0, {H})-isotopic compositions of minerals associated with marble-hosted ruby are all in agreement with the hypothesis, drawn from the unusual chemistry of {CO}2-{H}2{S}-{COS}-{S}-8-{A}l{O}({OH})-bearing fluids contained in fluid inclusions, that gem ruby formed at {P}-3 kbar and 620<{T}<670 degrees {C}, during thermal reduction of evaporite by organic matter, at high temperature-medium pressure metamorphism of platform carbonates during the {T}ertiary {I}ndia-{A}sia collision, {T}he carbonates were enriched in {A}l- and chromiferous-bearing detrital minerals, such as clay minerals that were deposited on the platform with the carbonates, and in organic matter. {R}uby formed during the retrograde metamorphic path, mainly by destabilization of muscovite or spinel. {T}he metamorphic fluid system was rich in {CO}2 released from devolatilisation {O}f {C}arbonates, and in fluorine, chlorine and boron released by molten salts ({N}a{C}l, {KC}l, {C}a{SO}4). {E}vaporites are key to explaining the formation of these deposits. {M}olten salts mobilized in situ {A}l and metal transition elements contained in marbles, leading to crystallization {O}f ruby.},
  keywords = {{A}sia ; {R}uby ; {M}arble ; {E}vaporite ; {M}etamorphism ; {G}eochemistry ; {S}table isotopes ; {G}enetic model},
  booktitle = {},
  journal = {{O}re {G}eology {R}eviews},
  volume = {34},
  numero = {1-2 {S}pecial {I}ssue},
  pages = {169--191},
  ISSN = {0169-1368},
  year = {2008},
  DOI = {10.1016/j.oregeorev.2008.03.003},
  URL = {https://www.documentation.ird.fr/hor/fdi:010044073},
}