Genesis of the volcanic-related Be-U-Mo Baiyanghe deposit, West Junggar (NW China), constrained by mineralogical, trace element and U-Pb isotope signatures of the primary U mineralisation

•Be-U-Mo mineralisation is hosted in Devonian rhyolitic tuff and Carboniferous granite.•Fractionated peralkaline A1-type rhyolitic tuffs are the dominant U and Be source.•The hydrothermal U mineralisation stage paragenetically postdates the Be ore stage.•The primary U mineralisation is charaterised by Pb-Nb-Ti-Zr-Mo-rich pitchblende.•Pitchblende has an in situ U-Pb isotopic minimum crystallisation age of 240 ± 7 Ma.