Hydrothermal deposits "sensu stricto" have been recovered during the FAMOUS cruise and Leg 54 of the Deep Sea Drilling Project near the Galapagos Spreading Centre. The studied sediments, mainly composed of clay material, have very poor REE concentrations, below about ten ppm. The shale-normalized patterns are characterized by a significant enrichment in heavy rare earths and show a negative Ce anomaly. The magnitude of this anomaly fluctuates but is generally lower than the seawater Ce anomaly. The geochemical characteristics of these hydrothermal deposits are in contrast with those of metalliferous sediments which are more enriched in trace elements, especially in REE.

Surface data from FAMOUS-Project (Heirtzler, J.R. and Van Andel, T.H., 1977, doi:10.1130/0016-7606(1977)882.0.CO;2), geographical position estimated from map.

Supplement to: Bonnot-Courtois, Chantal (1981): Distribution des terres rares dans les depots hydrothermaux de la zone FAMOUS et des galapagos-Comparaison avec les sediments metalliferes. Marine Geology, 39(1-2), 1-14