Plagiogranite zircons of Santa Elena and Nicoya yield SHRIMP 206Pb/238U ages of 125.3 ± 2.0 Ma and 90.9 ± 2.0 Ma to 88.5 ± 2.0 Ma, respectively.
Modeling suggests that Nicoya plagiogranites are ~ 10-15% residual liquids after fractional crystallization from its mafic parental source.
Plagiogranite chemistry is consistent with an oceanic arc and a MOR to oceanic plateau origin for Santa Elena and Nicoya, respectively.