Origin of Low-K Intermediate Lavas at Nekoma Volcano, NE Honshu Arc, Japan: Geochemical Constraints for Lower-Crustal Melts

at lower-crustal depths beneath the frontal arc is suggested by Extremely low-K basaltic andesite to andesite lavas at Nekoma geophysical observations. These observations further support lowervolcano, situated in the frontal volcanic zone of the NE Honshu crustal melting beneath Nekoma as the origin of the intermediate arc, were produced from melts that originated in the lower crust. low-K lavas. Multiple incompatible trace element model calculations suggest that extremely low-K basalt found in the same arc is a natural analog for the source composition. However, fractional crystallization, magma mixing, and crustal contamination models of primary lowK basalt cannot reproduce the Nekoma chemical composition.