Micro-PIXE and micro-IBIL characterization of lapis lazuli samples from Myanmar mines and implications for provenance study

The provenance of raw lapis lazuli used since the Neolithic Age for the realization of carved artefacts can be pivotingfor the reconstruction of ancient trade routes. The role of main provider of this material in ancient times is generally attributed tothe Badakhshan quarries (Afghanistan), although other deposits could have been exploited as well since antiquity. The systematicmulti-technique analysis of lapis lazuli rocks coming from four known source areas (located in present-day Afghanistan, Tajikistan,Siberia and Chile) has led in the last years to the compilation of a protocol for provenance determination. The protocol is basedon differences in the physical-chemical properties measured with non-invasive techniques (Ion Beam Analysis (IBA)), making itsuitable also for precious ancient artefacts. In this work, 10 new reference samples from the Mogok quarry (Myanmar), previouslysubjected to a complete petrographic and mineralogical characterization, have been analysed employing ?-PIXE (Proton InducedX-ray Emission) and ?-IBIL (Ion Beam Induced Luminescence) techniques. The subdivision of Myanmar samples into three groups,previously suggested, is corroborated by diopside trace elements concentrations. The results also allow to include Myanmar as anew provenance in the analytical protocol, indicating that provenance markers such as presence/absence of wollastonite, alteredpyrites and Sr content are still valid to discriminate also the Myanmar lapis lazuli from Chilean or Siberian ones. New weakermarkers (Zn content in diopside, Se and Cu contents in pyrite) are proposed for the discrimination of Myanmar from Afghan orTajik provenances; however, from the analysis it arose the need of investigating new mineral phases with IBA to find strong markersfor a definitive discrimination with samples from Southwest Asia.