Geochemistry. — A: K₂O versus SiO₂ plot after Peccerillo and Taylor (1976) for ultra-potassic Vosges rocks. Labelled colour circles: dated rocks of the present study, and granite-gneiss GG4 (loc. Fig. 3A; analysis from Tabaud et al., 2015). Crêtes granite, Ballons granite, Visean volcanites: data from Tabaud et al. (2015) and André (1983). Vosges lamprophyres are 57 analyses from Soder and Romer (2018). Small circles: Crêtes Mg-K granites (18 anal. labelled “CS” and “CN” by Tabaud et al., 2015). Empty squares: Ballons vaugnerites PR1 and 4N from André (1983), and 19 Ballons Mg-K porphyritic granites, labelled “BA” by Tabaud et al. (2015). Black squares: Ballons basic rocks, labelled BAB5 and BAB4 (e and f, resp., as in Fig. 3B). Empty diamonds: Ballons Visean volcanic rocks (8 anal. “VO” from Tabaud et al., 2015).— B: REE profiles for the dated rocks of the present study (reference chondrite values from Anders and Grevesse, 1989) grouped with profiles of selected samples (see A for details) from Tabaud et al. (2015), with mention for each group of the sum of the rare earth element contents (in μg/g) and the normalized ratio (La/Yb)_N — C: spidergram of the dated vaugnerites, reference N-MORB values from Hofmann (1988) following J. Scarrow (pers. comm. to FG). Grey: vaugnerite compilation by Scarrow et al. (2008, their Fig. 2E). — D: Labelled colour circles: dated vaugnerites of the present study, plottted using factors fn1 and fn2 of Scarrow et al. (2008, their Tab. 3 and Fig. 8) with their compiled data of: sh, shoshonites (•) − K-la, K-lamprophyres (Δ) − vg, vaugnerites (+).