Abstract
The petrology and chemistry of the Behind the Volcanic Front (BVF) lavas from eastern Nicaragua illustrate the complex nature of sources and processes. The older, Early Miocene (~17 Ma) low-Ti basalts--andesites are characterized by a strong LILE/HFSE depletion.
They are interpreted as relics of Early Miocene volcanic arc, largely analogous to the extinct Coyol arc further W. The prevalent high-Ti lavas are represented both by alkaline (Quaternary trachybasalts: Volcán Azul and Kukra Hill) and subalkaline (basalts--basaltic andesites: Late Miocene, ~ 11 Ma Great Corn Island and Quaternary, Pearl Lagoon) volcanic rocks.
All probably represent small-volume decompression melts of an OIB-like source with a strong Galápagos mantle imprint. The positive Sr--Nd isotopic correlation indicates an interaction between this component and a depleted mantle modified slightly by subduction-related influx of mainly Sr and Li.
This feeble signal stems most likely from the Miocene convergence episode.