Late Triassic submarine alkali basalts and hawaiites were collected from
two superimposed tectonic slices belonging to the Kara Dere - Sayrun
unit of the Middle Antalya nappes, southwestern Turkey. New
determinations on conodont faunas allow to date this sequence to the
Lower Carnian (Julian). The volcanic rocks show rather homogeneous
compositions, with high TiO2 and relatively low MgO and Ni contents
which suggest olivine fractionation. Their primitive mantle-normalised
multi-elements plots show Nb and Ta enrichments relative to La, Pb
negative anomalies and heavy rare earth element and Y depletions typical
of intraplate ocean island basalts. These characteristics are consistent
with the major and trace element compositions of their primary
clinopyroxene phenocrysts, which do not show any feature ascribable to
crustal contamination. The studied lavas display a restricted range of
epsilon Nd (+4.6 to +5.2) which falls within the range of ocean island
basalts. Their initial (Nd-143/Nd-144)i ratios are too low to be
explained by a simple mixing line between depleted MORB mantle (DMM) and
HIMU components. Their Pb and Nd isotopic compositions plot along a
mixing line between HIMU component and an enriched mantle, the
composition of which could be the result of the addition of about 5 to
8% of an EM2 component (recycled marine sediments) to DMM. The lack of
evidence for any continental crustal component. in their genesis could
be consistent with their emplacement in an intra-oceanic setting.