An Overview of the Geochemical Characteristics of Oceanic Carbonatites: New Insights from Fuerteventura Carbonatites (Canary Islands)

The occurrence of carbonatites in oceanic settings is very rare if compared with their
continental counterpart, having been reported only in Cape Verde and Canary Islands. This paper
provides an overview of the main geochemical characteristics of oceanic carbonatites, around which
many debates still exist regarding their petrogenesis. We present new data on trace elements in
minerals and whole-rock, together with the first noble gases isotopic study (He, Ne, Ar) in apatite,
calcite, and clinopyroxene from Fuerteventura carbonatites (Canary Islands). Trace elements show
a similar trend as Cape Verde carbonatites, almost tracing the same patterns on multi-element and
REE abundance diagrams. 3He/4He isotopic ratios of Fuerteventura carbonatites reflect a shallow
(sub-continental lithospheric mantle, SCLM) He signature in their petrogenesis, and they clearly
differ from Cape Verde carbonatites, i.e., fluids from a deep and low degassed mantle with a primitive
plume-derived He signature are involved in their petrogenesis.