Garnier V. auteur aut IRD Ohnenstetter D. auteur aut IRD Giuliani G. auteur aut IRD Maluski H. auteur aut IRD Deloule E. auteur aut IRD Trong T. P. auteur aut IRD Van L. P. auteur aut IRD Quang V. H. auteur aut IRD text journalArticle eng Marble-hosted ruby deposits occur in the Lo Gam tectonic zone along the northeastern flank of the Day Nui Con Voi Range in the Red River Shear Zone, in the northern part of Vietnam. Crystals of zircon included in ruby and spinel from Luc Yen and An Phu deposits were dated in situ by the U-Pb method with an ion microprobe. The patchy zoning of the zircon crystals and the wide range of ages (266-38 Ma) provide evidence for a complex metamorphic history, with at least two main thermal events: (1) Zircon included in spinel crystals probably crystallized during the Permian (256.6 +/- 9.4 Ma), with a possible reopening of their U-Pb system in the early Triassic (231.7 +/- 5.6 Ma). (2) Ruby formed at about 38 Ma when the Red River Shear Zone was the site of ductile deformation during the peak of metamorphism. The dating of zircon and phlogopite syngenetic with ruby documents the temporal relationship between high-temperature metamorphism and the cooling history of the Red River metamorphic belt. Ruby deposits hosted by marble sequences, in central and southeastern Asia seem to be an excellent marker; they allow an interpretation of the timing of the activity of Cenozoic structures linked to the collision between Indian and Eurasian continents. specialized ruby deposits marble zircon in situ U Pb dating Cenozoic ages ion probe data electron microprobe data cathodoluminescence northern Vietnam 43 Part 4 1315-1329 2005 0008-4476 https://www.documentation.ird.fr/hor/PAR00000645 10.2113/gscanmin.43.4.1315 0008-4476 https://www.documentation.ird.fr/hor/PAR00000645 IRD - Base Horizon / Pleins textes 2006-03-30 2017-08-23 PAR00000645 fre