Fig. 2
From: Fossil black smoker yields oxygen isotopic composition of Neoproterozoic seawater
(Eu/Eu*)CN ratio vs. (La/Yb)CN ratio in North Aït Ahmane serpentinites. Data are compared with global serpentinites and peridotites28,61,62,64,65 (in gray) and with black smoker-related serpentinites21,22,23,24 (in blue). Correlated enrichment in LREE and Eu in hydrothermalized serpentinites from Aït Ahmane tends toward those of black smoker fluids sampled at the sites of Rainbow19, Logatchev19, and Manus basin20 (in purple). Carbonates hosting tardi-orogenic mineralizations in Bou Azzer inlier, dated at 310 ± 5 Ma30, plot in a clearly different field (in yellow), discarding a post-obduction process18 for Eu and LREE enrichments in the serpentinites. Chondrite normalization values are from Barrat et al.66
