@article{fdi:010074801, title = {{F}luid inclusions study of trapiche and non-trapiche rubies from the {M}ong {H}su deposit, {M}yanmar}, author = {{G}iuliani, {G}aston and {D}ubessy, {J}. and {P}ignatelli, {I}. and {S}chwarz, {D}.}, editor = {}, language = {{ENG}}, abstract = {{T}he {M}ong {H}su ruby deposit in {M}yanmar is a marble-type deposit. {I}t is well-known for attractive crystals with dark violet/ blue to black cores and ruby rims, as well as for trapiche rubies. {T}hese exceptional rubies have a texture composed of six growth sectors separated by six dendrites running from a central core to the six corners. {F}luid inclusions ({FI}) have been studied in both types of ruby, i.e., trapiche and non-trapiche crystals. {M}icrothenuometry combined with {R}aman spectrometry investigations of primary and secondary {FI} proved the existence of {CO}2-{H}2{S}-{COS}-{S}-8-{A}l{O}({OH})-bearing fluids with diaspore and native sulfur daughter minerals. {T}he carbonic fluid belongs to the {CO}2-{H}2{S} system with {CO}2 as a dominant component. {M}inor {COS} (1-2 mol.%) and diaspore indicate that {H}2{O} (similar to 1 mol.%) was present in the paleofluid. {T}he amount of {H}2{S} in {FI} from trapiche ruby is between 6.9 and 7.4 mol.% for the dendrites and from 7.2 to 15.7 mol.% for the growth sectors. {T}he {H}2{S} content is approximately 10 mol.% in {FI} from non-trapiche rubies. {T}he presence of dawsonite and previous crushing data carried out on well-cleaned crystals of non-trapiche ruby indicate that an ionic salt melt was present at the time of ruby formation. {T}he non-detection of this melt in trapiche ruby is attributed to the small size of the remnants of molten salts, making it difficult to observe them under the microscope. {F}ollowing this hypothesis, the {FI} assemblages in rubies would correspond to the trapping of two immiscible fluids. i.e.. a carbonic phase in the {CO}2-{H}2{S}-{COS}-{S}-8-{A}l{O}({OH})system and molten salts. {S}uch fluid phases are considered to be the product of metamorphism of evaporites during devolatilization of carbonates and thermal-sulfate reduction. {T}he formation of trapiche ruby is discussed in terms of possible variations of the composition of the fluid, temperature, and pressure conditions. {T}he variation in density of the carbonic fluids from the dendrites (0.70 < ds < 0.78) to the growth sectors (0.56 < ds < 0.68) records variation of fluid pressure in the metamorphic system. {T}his variation led to episodically local fluid overpressure and hydraulic fracturing in the marble. {D}uring such episodes, changes in driving-force conditions allowed for the formation of the trapiche texture in ruby: the development of dendrites and growth sectors occurred under high and low driving-force conditions, respectively. {N}on-trapiche ruby in veinlets formed concurrently under thermodynamic conditions similar to those registered for the growth sectors in trapiche ruby.}, keywords = {{M}ong {H}su deposit ; {M}yanmar ; ruby ; trapiche texture ; fluid inclusions ; microthermometry ; {R}aman spectrometry ; {CO}2-{H}2{S}-{COS}-{S}-8-{A}l{O}({OH}) system ; texture formation ; {MYANMAR}}, booktitle = {}, journal = {{C}anadian {M}ineralogist}, volume = {56}, numero = {5}, pages = {691--703}, ISSN = {0008-4476}, year = {2018}, DOI = {10.3749/canmin.1800013}, URL = {https://www.documentation.ird.fr/hor/fdi:010074801}, }