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Fluid Inclusions Study of Trapiche and Non-Trapiche Rubies from the Mong Hsu Deposit, Myanmar

2018; Mineralogical Association of Canada; Volume: 56; Issue: 5 Linguagem: Inglês

10.3749/canmin.1800013

1499-1276

Gaston Giuliani, Jean Dubessy, Isabella Pignatelli, Dietmar Schwarz,

Geological and Geochemical Analysis

Research Article| September 01, 2018 Fluid Inclusions Study of Trapiche and Non-Trapiche Rubies from the Mong Hsu Deposit, Myanmar Gaston Giuliani; Gaston Giuliani § Université Paul Sabatier, GET/IRD, UMR CNRS-IRD-CNES 5563, 14 avenue Edouard Belin, F-31400 Toulouse, FranceUniversité de Lorraine, CRPG UMR 7358 CNRS-UL, 15 rue Notre-Dame-des-Pauvres, BP20, 54501 Vandœuvre-lès-Nancy cedex, France § Corresponding author e-mail address: giuliani@crpg.cnrs-nancy.fr Search for other works by this author on: GSW Google Scholar Jean Dubessy; Jean Dubessy Université de Lorraine, Géoressources UMR 7359 CNRS-UL, BP 70239, 54506 Vandœuvre-lès-Nancy cedex, France Search for other works by this author on: GSW Google Scholar Isabella Pignatelli; Isabella Pignatelli Université de Lorraine, Géoressources UMR 7359 CNRS-UL, BP 70239, 54506 Vandœuvre-lès-Nancy cedex, France Search for other works by this author on: GSW Google Scholar Dietmar Schwarz Dietmar Schwarz ICA Gemlab, 6th Floor, Jewelry Trade Center Silom Road, Khwaeng Silom, Khet Bang Rak, Bangkok 10500, Thailand Search for other works by this author on: GSW Google Scholar Author and Article Information Gaston Giuliani § Université Paul Sabatier, GET/IRD, UMR CNRS-IRD-CNES 5563, 14 avenue Edouard Belin, F-31400 Toulouse, FranceUniversité de Lorraine, CRPG UMR 7358 CNRS-UL, 15 rue Notre-Dame-des-Pauvres, BP20, 54501 Vandœuvre-lès-Nancy cedex, France Jean Dubessy Université de Lorraine, Géoressources UMR 7359 CNRS-UL, BP 70239, 54506 Vandœuvre-lès-Nancy cedex, France Isabella Pignatelli Université de Lorraine, Géoressources UMR 7359 CNRS-UL, BP 70239, 54506 Vandœuvre-lès-Nancy cedex, France Dietmar Schwarz ICA Gemlab, 6th Floor, Jewelry Trade Center Silom Road, Khwaeng Silom, Khet Bang Rak, Bangkok 10500, Thailand § Corresponding author e-mail address: giuliani@crpg.cnrs-nancy.fr Publisher: Mineralogical Association of Canada First Online: 29 Oct 2018 Online Issn: 1499-1276 Print Issn: 0008-4476 © 2018 Mineralogical Association of Canada The Canadian Mineralogist (2018) 56 (5): 691–703. https://doi.org/10.3749/canmin.1800013 Article history First Online: 29 Oct 2018 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Gaston Giuliani, Jean Dubessy, Isabella Pignatelli, Dietmar Schwarz; Fluid Inclusions Study of Trapiche and Non-Trapiche Rubies from the Mong Hsu Deposit, Myanmar. The Canadian Mineralogist 2018;; 56 (5): 691–703. doi: https://doi.org/10.3749/canmin.1800013 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyThe Canadian Mineralogist Search Advanced Search Abstract The Mong Hsu ruby deposit in Myanmar is a marble-type deposit. It is well-known for attractive crystals with dark violet/blue to black cores and ruby rims, as well as for trapiche rubies. These exceptional rubies have a texture composed of six growth sectors separated by six dendrites running from a central core to the six corners.Fluid inclusions (FI) have been studied in both types of ruby, i.e., trapiche and non-trapiche crystals. Microthermometry combined with Raman spectrometry investigations of primary and secondary FI proved the existence of CO2-H2S-COS-S8-AlO(OH)-bearing fluids with diaspore and native sulfur daughter minerals. The carbonic fluid belongs to the CO2–H2S system with CO2 as a dominant component. Minor COS (1–2 mol.%) and diaspore indicate that H2O (∼1 mol.%) was present in the paleofluid. The amount of H2S 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. The H2S content is approximately 10 mol.% in FI from non-trapiche rubies.The 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. The 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. Following this hypothesis, the FI assemblages in rubies would correspond to the trapping of two immiscible fluids, i.e., a carbonic phase in the CO2–H2S–COS–S8–AlO(OH)-system and molten salts. Such fluid phases are considered to be the product of metamorphism of evaporites during devolatilization of carbonates and thermal-sulfate reduction.The formation of trapiche ruby is discussed in terms of possible variations of the composition of the fluid, temperature, and pressure conditions. The 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. This variation led to episodically local fluid overpressure and hydraulic fracturing in the marble. During 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. Non-trapiche ruby in veinlets formed concurrently under thermodynamic conditions similar to those registered for the growth sectors in trapiche ruby. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.